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Meade MJ, Dreyer CW. Tooth agenesis: An overview of diagnosis, aetiology and management. JAPANESE DENTAL SCIENCE REVIEW 2023; 59:209-218. [PMID: 37645267 PMCID: PMC10461125 DOI: 10.1016/j.jdsr.2023.07.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Revised: 06/25/2023] [Accepted: 07/02/2023] [Indexed: 08/31/2023] Open
Abstract
Patients with one or more developmentally absent teeth are routinely encountered in dental practice. Tooth agenesis can be associated with significant functional, aesthetic and psycho-social problems. The present article provides an overview of the prevalence and aetiology of tooth agenesis, as well as the condition's clinical characteristics and management options with reference to the evidence base. A timely diagnosis can facilitate the appropriate planning and management which might not be straightforward, and patient care will likely require multi- and inter-disciplinary input. It is critical that dental care practitioners are aware of the clinical characteristics and management options for tooth agenesis.
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Affiliation(s)
- Maurice J. Meade
- Orthodontic Unit, Adelaide Dental School, The University of Adelaide, South Australia, Australia
| | - Craig W. Dreyer
- Orthodontic Unit, Adelaide Dental School, The University of Adelaide, South Australia, Australia
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Kjær I, Svanholt M, Svanholt P. The location of the permanent mandibular canine as identified in orthopantomograms from children younger than 5 years of age: a case series study. Eur Arch Paediatr Dent 2023; 24:613-619. [PMID: 37615811 PMCID: PMC10600042 DOI: 10.1007/s40368-023-00825-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 07/08/2023] [Indexed: 08/25/2023]
Abstract
AIM The aim of this case series study is to describe where the crowns of the permanent mandibular canines are located in early childhood in relation to the preceding primary canines. MATERIALS AND METHODS From a sample of 31 orthopantomograms from children, younger than 5 years of age, the location of the mandibular canines was analysed by visual inspection. The radiographs were taken due to different deviations in the dentition and forwarded during a period of 28 years for elucidating different diagnostic questions. From an embryological point of view, the primary canine was considered as a stable structure in the jawbone. A longitudinal axis through the primary canine was named the canine axis. The initial site of the permanent crown was the site, where the permanent lamina "placed" the tooth bud for final development. A normal site was determined when the canine axis passed though the permanent crown and a pathological site was determined when this did not happen. RESULTS Normal sites for the permanent crowns were observed in 19 cases and abnormal sites in 8 cases. In four cases, the interrelationship between the canine axis and the permanent crown could not be decided. The study demonstrated that the tooth germ for the permanent canine can start initial formation misplaced distally or mesially to the preceding primary tooth. CONCLUSION The study demonstrates different malpositions of the initial crowns of the permanent mandibular canines in children younger than 5 years of age. The results are considered of importance for future understanding of the aetiology behind ectopic mandibular canines.
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Affiliation(s)
- I Kjær
- Department of Odontology. Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
| | - M Svanholt
- Section of Orthodontics, Department of Odontology, Faculty of Health and Medical Sciences, Copenhagen, Denmark
- Copenhagen Municipal Clinic of Orthodontics, Copenhagen, Denmark
| | - P Svanholt
- Section of Orthodontics, Department of Odontology, Faculty of Health and Medical Sciences, Copenhagen, Denmark
- Guldborgsund Municipal Clinic of Orthodontics, Nykøbing Falster, Denmark
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Duke A, Paterson M, P Ashley M, MacNab L. The genetic basis of hypodontia in dental development. Br Dent J 2023; 235:525-528. [PMID: 37828195 DOI: 10.1038/s41415-023-6384-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 07/05/2023] [Accepted: 07/06/2023] [Indexed: 10/14/2023]
Abstract
Dental agenesis is one of the most common developmental anomalies in humans, characterised by the developmental absence of one or more teeth. It can present as an isolated condition (non-syndromic hypodontia) or associated with a syndrome (syndromic hypodontia). This paper aims to review the genetic basis of hypodontia with reference to aetiology, classification and the subsequent clinical features.Significant progress has been made to identify the developmental basis of tooth formation, though there is still a lack of knowledge within the literature of the aetiological basis of inherited tooth loss.Gene anomalies or mutations in WNT10A, MSX1, PAX9, AXIN2 and EDA appear to be most critical during tooth development, leading to various forms of tooth agenesis.
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Affiliation(s)
- Alice Duke
- Aberdeen Dental Hospital and Institute of Dentistry, Aberdeen, Scotland, UK.
| | - Michael Paterson
- James Cook University Hospital, South Tees Hospital NHS Foundation Trust, UK
| | | | - Lorna MacNab
- Glasgow Dental Hospital and School, Glasgow, Scotland, UK
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Kjær I. Abnormal premolar eruption: classification, aetiology, and treatment based on a case series study. Eur Arch Paediatr Dent 2021; 22:1077-1086. [PMID: 34520002 DOI: 10.1007/s40368-021-00658-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 08/10/2021] [Indexed: 11/26/2022]
Abstract
AIM The aim of this case series study is to classify deviations in mandibular and maxillary premolar eruption according to aetiology, with a focus on the resorption pattern in the preceding primary molars. The purpose is also to give treatment guidance based on aetiology. MATERIALS AND METHODS Radiographic material from 64 cases with abnormal premolar eruptions were grouped into three eruptions phases: Phase 1, from tooth bud to early root formation, sub-grouped according to "ankylosis" or "not ankylosis" of the primary molars; Phase 2, from start of eruption to the penetration of gingiva, sub-grouped according to normal or abnormal resorption of the primary molars and Phase 3, eruption after penetration of gingiva. RESULTS Phase 1: early ankylosis of primary molars, ectopic locations of the premolar crown, including occlusally displacement in relation to the primary molar, are demonstrated. Not ankylosed primary molar: different positions, even an upside-down position of the premolar, are demonstrated. The conditions are explained in relation to the early migration pattern of the premolar tooth bud. Regarding treatment, in cases with ankylosed primary molars these should be extracted as soon as diagnosed and in cases with not ankylosed primary molars these should be extracted when root formation of the premolars has started. The premolars should be observed and saved if possible. Phase 2: non-exfoliation of primary molar, aetiology and treatment of premolars depend on tissue types involved. In bone dysplasia, the eruption of premolars is delayed. In these cases, the primary molars should be extracted when eruptive movements of the premolars have started. In cases with ectoderm deviation, the crown follicle does not function normally during the resorption of the primary molars and the recommended treatment is extraction of primary molars before root closure of premolars. In cases in Phase 2 where the premolars were ankylosed these should be surgical removed. Phase 3: different aetiologies are highlighted, with focus on abnormal innervation and enzyme defects. The premolars are seemingly ankylosed, and surgery might be the only treatment. CONCLUSION The case series presented demonstrate how ectopic and arrested premolars have different aetiologies and as a consequence, different treatments. The study highlights several aspects in pathological eruption, which still need to be elucidated.
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Affiliation(s)
- I Kjær
- Department of Odontology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
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Use of a Modified Nance Appliance for Esthetic Rehabilitation of a Child Patient with Rare Nonfamilial and Nonsyndromic Oligodontia. Case Rep Dent 2021; 2021:5444257. [PMID: 34336303 PMCID: PMC8318745 DOI: 10.1155/2021/5444257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 07/10/2021] [Indexed: 11/18/2022] Open
Abstract
Congenital absence of more than 6 teeth except the third molar is known as oligodontia. It can affect both primary and permanent dentitions. The affected individuals usually demonstrate esthetic, functional, and psychological concerns. The present case report is about a 4-year-old female patient with multiple missing (both primary and permanent) teeth with esthetic and social problems. On extraoral examination, the patient demonstrated upper lip relapse due to missing anterior teeth. On physical examination, no other abnormality was detected in relation to the hair, appendages, or presence of a cleft. On intraoral and radiographic examination, 21 teeth were missing, which included both the primary and the permanent tooth buds. To encourage a positive behavioral change, it was decided to carry out prosthetic intervention using a modified fixed Nance appliance and acrylic teeth. After the replacement of the missing teeth, a marked improvement in the profile and esthetics was seen.
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Kjær I. New diagnostics of the dentition on panoramic radiographs—Focusing on the peripheral nervous system as an important aetiological factor behind dental anomalies. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/j.odw.2011.10.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- Inger Kjær
- Department of Orthodontics, Institute of Odontology, Faculty of Health Sciences, University of Copenhagen, 20 Nørre Alle, DK-2200 Copenhagen N, Denmark
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Arai K. Tooth agenesis patterns in Japanese orthodontic patients with nonsyndromic oligodontia. Am J Orthod Dentofacial Orthop 2019; 156:238-247. [DOI: 10.1016/j.ajodo.2018.09.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2018] [Revised: 09/01/2018] [Accepted: 09/01/2018] [Indexed: 12/31/2022]
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Localised scleroderma en coup de sabre affecting the skin, dentition and bone tissue within craniofacial neural crest fields. Clinical and radiographic study of six patients. Eur Arch Paediatr Dent 2019; 20:339-350. [DOI: 10.1007/s40368-019-00427-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 02/27/2019] [Indexed: 10/27/2022]
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Patterns of congenitally missing teeth of non-syndromic and syndromic patients treated at a single-center over the past thirty years. Arch Oral Biol 2018; 98:140-147. [PMID: 30496934 DOI: 10.1016/j.archoralbio.2018.11.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 11/14/2018] [Accepted: 11/15/2018] [Indexed: 11/21/2022]
Abstract
OBJECTIVES Literature regarding congenitally-missing-teeth (CMT) is lacking especially on CMT-patterns. Thus, the aim of this study was to present an in-depth analysis of 843 patients with CMT treated at a single-center over the past thirty years. DESIGN Age, date-of-birth-year, gender, medical- and family-history, CMT-types, -numbers, -severity, -region, -symmetry, -patterns using the tooth agenesis code (TAC), and -growth types of all clinically and radiographically diagnosed CMT-patients were collected. Age and occurrence of syndromes were used to divide CMT-patients into non-syndromic patients older than nine years (group1) and syndromic CMT-patients (group2). Groups were compared especially regarding gender and CMT-severity. RESULTS The average CMT-number per patient was 5.5 (group1, n = 816, 59.9% female) and 15.1 (group2, n = 27, 29.6% female). There were significant less male (40.1% vs. 70.4%, respectively; P = 0.002) as well as significantly less male-oligodontia (44.8% vs. 73.9%, respectively; P = 0.009) in group1 than in group2. Group1 resulted in decreased prevalence of similar CMT-patterns with severity; the most prevalent CMT was the 2nd premolar; there were no significant differences between the right and left side, whereas more CMT affected the maxilla; the majority of patients presented with bilateral-CMT (82.8%); females were more affected by CMT but more males had severer forms; certain single CMT differed by gender, and CMT was related to first-grade-relatives. CONCLUSION The majority of CMT-patients presented with hypodontia. Furthermore, same CMT-patterns seem more like to be present in patients with milder forms of tooth agenesis. Gender-specific association regarding CMT-number, severity groups, and single CMT were detected.
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Higashihori N, Takada JI, Katayanagi M, Takahashi Y, Moriyama K. Frequency of missing teeth and reduction of mesiodistal tooth width in Japanese patients with tooth agenesis. Prog Orthod 2018; 19:30. [PMID: 30123921 PMCID: PMC6098995 DOI: 10.1186/s40510-018-0222-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 06/05/2018] [Indexed: 11/10/2022] Open
Abstract
Background Tooth agenesis can involve one or more congenitally missing teeth (CMT) and is the most common congenital dental anomalies in humans. Tooth agenesis and reduction of mesiodistal tooth width are reportedly associated, suggesting that the pathogenesis of the two conditions is related. The current study analyzed the frequency of tooth agenesis and mesiodistal tooth width in cases of hypodontia (1–5 CMT) and oligodontia (≥ 6 CMT) in Japanese patients based on the hypothesis that reductions in mesiodistal tooth width are more frequently associated with oligodontia than hypodontia. Methods Japanese patients with tooth agenesis were divided into hypodontia cases (60 female and 25 male, mean age 19.6 years, mean CMT number 1.31 ± 1.65) and oligodontia cases (26 female and 25 male, mean age 14.6 years, mean CMT number 8.07 ± 2.39). Controls included patients with a skeletal class I relationship and no CMT (female and 60 male, mean age 20.8 years). Dental casts and orthopantomograms were used to analyze the CMT frequency and mesiodistal tooth width for each group. The Kruskal-Wallis test, the Mann-Whitney U test, and Spearman’s rank correlation were used for statistical analysis. Results In the hypodontia group, mandibular second premolars were the most frequently missing tooth type (25.9%), followed by mandibular and maxillary lateral incisors (19.4 and 17.1%, respectively). In the oligodontia group, mandibular second premolars were the most frequently missing tooth type (88.2%), followed by maxillary second premolars (87.3%) and first premolars (63.7%). In female subjects in the hypodontia group, only maxillary lateral incisors and mandibular first molars were significantly smaller than those of the female control subjects. In contrast, in the oligodontia group, more tooth types were significantly smaller than those of the control, for both sexes. Except for maxillary second premolars in female subjects, correlations were apparent for all tooth types in both sexes. Conclusions Compared to hypodontia, more tooth types exhibited reduced mesiodistal tooth width in oligodontia. Correlations between CMT number and mesiodistal tooth width support the hypothesis that reduction of mesiodistal tooth width are more frequently observed in Japanese oligodontia patients than in Japanese hypodontia patients.
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Affiliation(s)
- Norihisa Higashihori
- Section of Maxillofacial Orthognathics, Department of Maxillofacial/Neck Reconstruction, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan.
| | - Jun-Ichi Takada
- Section of Maxillofacial Orthognathics, Department of Maxillofacial/Neck Reconstruction, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan
| | - Minami Katayanagi
- Section of Maxillofacial Orthognathics, Department of Maxillofacial/Neck Reconstruction, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan
| | - Yuki Takahashi
- Section of Maxillofacial Orthognathics, Department of Maxillofacial/Neck Reconstruction, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan
| | - Keiji Moriyama
- Section of Maxillofacial Orthognathics, Department of Maxillofacial/Neck Reconstruction, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan
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Al-Ani AH, Antoun JS, Thomson WM, Merriman TR, Farella M. Hypodontia: An Update on Its Etiology, Classification, and Clinical Management. BIOMED RESEARCH INTERNATIONAL 2017; 2017:9378325. [PMID: 28401166 PMCID: PMC5376450 DOI: 10.1155/2017/9378325] [Citation(s) in RCA: 127] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2016] [Revised: 02/14/2017] [Accepted: 02/19/2017] [Indexed: 11/28/2022]
Abstract
Hypodontia, or tooth agenesis, is the most prevalent craniofacial malformation in humans. It may occur as part of a recognised genetic syndrome or as a nonsyndromic isolated trait. Excluding third molars, the reported prevalence of hypodontia ranges from 1.6 to 6.9%, depending on the population studied. Most affected individuals lack only one or two teeth, with permanent second premolars and upper lateral incisors the most likely to be missing. Both environmental and genetic factors are involved in the aetiology of hypodontia, with the latter playing a more significant role. Hypodontia individuals often present a significant clinical challenge for orthodontists because, in a number of cases, the treatment time is prolonged and the treatment outcome may be compromised. Hence, the identification of genetic and environmental factors may be particularly useful in the early prediction of this condition and the development of prevention strategies and novel treatments in the future.
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Affiliation(s)
- Azza Husam Al-Ani
- Department of Oral Sciences, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
| | - Joseph Safwat Antoun
- Department of Oral Sciences, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
| | - William Murray Thomson
- Department of Oral Sciences, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
| | - Tony Raymond Merriman
- Department of Biochemistry, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
| | - Mauro Farella
- Department of Oral Sciences, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
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Berniczei-Roykó Á, Tappe JH, Krinner A, Gredes T, Végh A, Gábor K, Linkowska-Świdzińska K, Botzenhart UU. Radiographic Study of the Prevalence and Distribution of Hypodontia Associated with Unilateral and Bilateral Clef Lip and Palate in a Hungarian Population. Med Sci Monit 2016; 22:3868-3885. [PMID: 27767023 PMCID: PMC5077290 DOI: 10.12659/msm.897957] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Background Cleft defects are one of the most frequent birth-deformities of the orofacial region and they are commonly associated with anomalies of the tooth structure, size, shape, formation, eruption, and tooth number. The aim of our study was to evaluate the prevalence, distribution, and potential association of combined hypodontia in cleft-affected patients with regard to all types of teeth in both jaws in the permanent dentition. Material/Methods This retrospective radiographic analysis included patients with various types of clefts treated orthodontically in the Department of Orofacial Orthopedics and Orthodontics at Heim Pàl Children’s Hospital, Budapest. There were 150 patients (84 males, 66 females) with non-syndromic unilateral (UCLP; n=120 patients) or bilateral (BCLP; n=30 patients) cleft formation (lip, alveolus and palate) who met the inclusion criteria. Statistical analysis was performed using the chi-square test and Fisher’s exact test (significance level p<0.05). Results Hypodontia was significantly more frequent in patients with cleft-sided lateral incisor (104 patients, 69%), with a total of 235 missing teeth, followed by the second premolars of the upper and lower jaw. A significant correlation of congenital missing teeth was observed in left-sided clefts between the upper and lower second premolar in the cleft area. Conclusions Hypodontia inside and outside the cleft area was frequently observed. This should affect the therapy plans, especially if the cleft-sided premolar is also absent. Further comprehensive research including numerous random samples is necessary for better estimating other possible associations.
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Affiliation(s)
- Ádám Berniczei-Roykó
- Department of Orthodontics, Faculty of Medicine Carl Gustav Carus, TU Dresden, Dresden, Germany
| | - Jan-Hendrik Tappe
- Department of Orthodontics, Faculty of Medicine Carl Gustav Carus, TU Dresden, Dresden, Germany
| | - Axel Krinner
- Institute for Medical Informatics and Biometry (IMB), Faculty of Medicine Carl Gustav Carus, TU Dresden, Dresden, Germany
| | - Tomasz Gredes
- Department of Orthodontics, Faculty of Medicine Carl Gustav Carus, TU Dresden, Dresden, Germany
| | - András Végh
- Department of Orofacial Orthopedics and Orthodontics, Heim Pàl Children's Hospital, Budapest, Hungary
| | - Katona Gábor
- Department of Oto-Rhino-Laryngology and Bronchology, Heim Pàl Children's Hospital, Budapest, Hungary
| | | | - Ute Ulrike Botzenhart
- Department of Orthodontics, Faculty of Medicine Carl Gustav Carus, TU Dresden, Dresden, Germany
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Kjær I. [Ectoderm, mesoderm and neuroectoderm are tissue types of importance for understanding and preventing root resorption. Clinical guidelines]. Orthod Fr 2016; 87:309-319. [PMID: 27726839 DOI: 10.1051/orthodfr/2016028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 06/22/2016] [Indexed: 06/06/2023]
Abstract
INTRODUCTION This three-part article summarizes ideas already described elsewhere by the author. Part 1. New way of diagnosing the dentition. For diagnostic purposes origin and appearance of the three tissue types - ectoderm, mesoderm (ectomesenchyme) and peripheral nerves - are depicted on orthopantomograms. Same tissue types are marked on the root surface (peri-root sheet). Part 2. Factors provoking root resorption. Resorption can be explained from the composition of the peri-root sheet. Deviations (inborn or acquired) in each of the three tissue layers can provoke inflammation, resulting in resorption. Orthodontic forces resulting in resorption can occur in normal peri-root sheets, but also in peri-root sheets with inborn deviations, important to diagnose. Part 3. How to prevent root resorption - Clinical guidelines. General diseases and different dental morphologies are signs predisposing for root resorption (ectoderm and mesoderm), so are local or general virus attacks (neuroectoderm). Resorption often occurs in dentitions never treated orthodontically. MATERIAL AND METHOD The author performed a review of the literature in order to present a new diagnostic approach incorporating histological and embryological concepts. RESULTS The review revealed different etiologies and sites involved in root resorption. Patients presenting variations of the peri-root sheet are most exposed to root resorption. DISCUSSION At this stage, it is difficult to diagnose these variations. The author offers diagnostic recommendations to be followed prior to orthodontic treatment. Even when no orthodontic treatment is given, root resorption can occur unexpectedly. In these cases, resorption prevention is currently impossible.
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Micro-CT assessment of changes in the morphology and position of the immature mandibular canal during early growth. Surg Radiol Anat 2016; 39:185-194. [PMID: 27177907 DOI: 10.1007/s00276-016-1694-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 05/09/2016] [Indexed: 10/21/2022]
Abstract
PURPOSE The mandibular canal contributes to the development and growth of the mandible, as it acts as a conduit for the growing inferior alveolar neurovascular structures. A clear understanding of the canal's pathway is, therefore, important in interpreting the growth pattern of the inferior alveolar neurovascular bundle. This study investigated the position of the mandibular canal within the body of the mandible and its general dimensions within a pediatric collection of mandibles. METHODS The sample included 45 mandibles and was subdivided into three: group 1 (30 gestational weeks to birth), group 2 (birth to 12 months), and group 3 (1 to 4 years). Mandibles were scanned using a Nikon XTH 225L micro-CT unit. Scanning conditions ranged between 85 kV/83 µA and 100 kV/100 µA. Measurements included: the maximum width and height of the mandibular canal and distances between the mandibular canal and the relevant surfaces of the mandible. Data analysis included an ANOVA, MANOVA, and principal component analysis. RESULTS The mandibular canal increased significantly in size from 30 gestational weeks to 12 months relative to the deciduous molar crypts. Postnatally, the mandibular canal increased significantly in height at the level of the second deciduous molar crypt. The canal lies closer to the buccal surface in the region of the first and second deciduous molar teeth. CONCLUSION The consistency in the positioning of the mandibular canal within the body of the mandible may assist in predicting the occurrence of aberrant growth patterns, particularly during the initial stages of growth.
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Accessory mandibular foramen during dental implant placement: case report and review of literature. IMPLANT DENT 2016; 23:116-24. [PMID: 24637530 DOI: 10.1097/id.0000000000000056] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Accurate knowledge of vital anatomical structures, such as the inferior alveolar nerve, mental nerve, and mental foramen, is critical to achieve favorable results during oral surgical procedures and dental implant placement. Although uncommon, variations in mandibular foramina have been reported and if unnoticed and, as a result, injured, may lead to patient morbidity, neurosensory disturbances, and other undesired complications. We present a case report of identification of an accessory mandibular foramen (AMF) encountered during placement of 2 dental implants for a mandibular implant-retained overdenture and demonstrate appropriate management. In addition, we propose a more reasonable terminology for such accessory foramina so as to facilitate communication through common terminology among health care providers. As conventional radiography (periapical and panoramic films) may not allow for proper identification of such anatomical variations, cone-beam computed tomography may be useful in the diagnosis of AMF during treatment planning of dental implants in the mandible.
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Jasemi A, Sonnesen L. Tooth agenesis and craniofacial morphology in pre-orthodontic children with and without morphological deviations in the upper cervical spine. World J Stomatol 2016; 5:15-21. [DOI: 10.5321/wjs.v5.i1.15] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 10/14/2015] [Accepted: 12/02/2015] [Indexed: 02/06/2023] Open
Abstract
AIM: To analyze differences in prevalence and pattern of tooth agenesis and craniofacial morphology between non syndromic children with tooth agenesis with and without upper cervical spine morphological deviations and to analyze associations between craniofacial morphology and tooth agenesis in the two groups together.
METHODS: One hundred and twenty-six pre-orthodontic children with tooth agenesis were divided into two groups with (19 children, mean age 11.9) and without (107 children, mean age 11.4) upper spine morphological deviations. Visual assessment of upper spine morphology and measurements of craniofacial morphology were performed on lateral cephalograms. Tooth agenesis was evaluated from orthopantomograms.
RESULTS: No significant differences in tooth agenesis and craniofacial morphology were found between children with and without upper spine morphological deviations (2.2 ± 1.6 vs 1.94 ± 1.2, P > 0.05) but a tendency to a different tooth agenesis pattern were seen in children with morphological deviations in the upper spine. In the total group tooth agenesis was associated with the cranial base angle (n-s-ba, r = 0.23, P < 0.01), jaw angle (ML/RLar, r = 0.19, P < 0.05), mandibular inclination (NSL/ML, r = -0.21, P < 0.05), mandibular prognathia (s-n-pg, r = 0.25, P < 0.01), sagittal jaw relationship (ss-n-pg, r = -0.23, P < 0.5), overjet (r = -0.23, P < 0.05) and overbite (r = -0.25, P < 0.01).
CONCLUSION: Etiology of tooth agenesis in children with upper spine morphological deviations was discussed. The results may be valuable for the early diagnosis and treatment planning of non syndromic children with tooth agenesis.
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Pannu P, Galhotra V, Ahluwalai P, Gambhir RS. Non-syndromic oligodontia in permanent dentition: a case report. Ghana Med J 2015; 48:173-6. [PMID: 25709129 DOI: 10.4314/gmj.v48i3.10] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Tooth agenesis is one of the most common congenital anomalies seen in humans. Although absence of one or more teeth is common but absence of multiple teeth is rare. Oligodontia is a rare developmental anomaly, involving agenesis of six or more permanent teeth, excluding the third molars. The reported prevalence of oligodontia in permanent dentition is 0.14%. Oligodontia can present as an isolated condition or as a part of a syndrome. The present case report highlights a unique case of non syndromic oligodontia, with agenesis of four permanent incisors, left permanent canine and right second premolar in the mandibular arch and its management with a novel fixed functional prosthetic appliance. Prosthetic rehabilitation is an urgent need for these kind of patients so that they do not suffer from masticatory and esthetic problems which can eventually lower the self esteem of individuals.
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Affiliation(s)
- P Pannu
- Gian Sagar Dental College and Hospital - Pediatric and Preventive Dentistry, Rajpura, India
| | - V Galhotra
- Gian Sagar Dental College and Hospital - Pediatric and Preventive Dentistry, Rajpura, India
| | - P Ahluwalai
- Gian Sagar Dental College and Hospital - Pediatric and Preventive Dentistry, Rajpura, India
| | - R S Gambhir
- Sector 7C, Chandigarh, Chandigarh 160019, India
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Guilleminault C, Abad VC, Chiu HY, Peters B, Quo S. Missing teeth and pediatric obstructive sleep apnea. Sleep Breath 2015; 20:561-8. [PMID: 26330227 DOI: 10.1007/s11325-015-1238-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 07/30/2015] [Accepted: 08/04/2015] [Indexed: 12/19/2022]
Abstract
BACKGROUND Missing teeth in early childhood can result in abnormal facial morphology with narrow upper airway. The potential association between dental agenesis or early dental extractions and the presence of obstructive sleep apnea (OSA) was investigated. METHODS We reviewed clinical data, results of polysomnographic sleep studies, and orthodontic imaging studies of children with dental agenesis (n = 32) or early extraction of permanent teeth (n = 11) seen during the past 5 years and compared their findings to those of age-, gender-, and body mass index-matched children with normal teeth development but tonsilloadenoid (T&A) hypertrophy and symptoms of OSA (n = 64). RESULTS The 31 children with dental agenesis and 11 children with early dental extractions had at least 2 permanent teeth missing. All children with missing teeth (n = 43) had clinical complaints and signs evoking OSA. There was a significant difference in mean apnea-hypopnea indices (AHI) in the three dental agenesis, dental extraction, and T&A studied groups (p < 0.001), with mean abnormal AHI lowest in the pediatric dental agenesis group. In the children with missing teeth (n = 43), aging was associated with the presence of a higher AHI (R (2) = 0.71, p < 0.0001). CONCLUSION Alveolar bone growth is dependent on the presence of the teeth that it supports. The dental agenesis in the studied children was not part of a syndrome and was an isolated finding. Our children with permanent teeth missing due to congenital agenesis or permanent teeth extraction had a smaller oral cavity, known to predispose to the collapse of the upper airway during sleep, and presented with OSA recognized at a later age. Due to the low-grade initial symptomatology, sleep-disordered breathing may be left untreated for a prolonged period with progressive worsening of symptoms over time.
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Affiliation(s)
- Christian Guilleminault
- Stanford University Sleep Medicine Division, Stanford Outpatient Medical Center, 450 Broadway Street, Pavilion B 2nd floor, MC 5730, Redwood City, CA, 94063-5730, USA.
| | - Vivien C Abad
- Stanford University Sleep Medicine Division, Stanford Outpatient Medical Center, 450 Broadway Street, Pavilion B 2nd floor, MC 5730, Redwood City, CA, 94063-5730, USA
| | - Hsiao-Yean Chiu
- Stanford University Sleep Medicine Division, Stanford Outpatient Medical Center, 450 Broadway Street, Pavilion B 2nd floor, MC 5730, Redwood City, CA, 94063-5730, USA
| | - Brandon Peters
- Stanford University Sleep Medicine Division, Stanford Outpatient Medical Center, 450 Broadway Street, Pavilion B 2nd floor, MC 5730, Redwood City, CA, 94063-5730, USA
| | - Stacey Quo
- Department of Orthodontics, University of California San Francisco Dental School, San Francisco, USA
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Ceyhan D, Kirzioglu Z, Calapoglu NS. Mutations in the MSX1 gene in Turkish children with non-syndromic tooth agenesis and other dental anomalies. Indian J Dent 2015; 5:172-82. [PMID: 25565750 PMCID: PMC4260382 DOI: 10.4103/0975-962x.144717] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Aim: To search for mutations on the MSX1 gene and to present a genetic basis for non-syndromic tooth agenesis in conjunction with dental anomalies in a Turkish population. Materials and Methods: The patients included in this study were otherwise healthy, with ages ranging from seven to eighteen years. Eighty-two of them had one to six teeth missing (Group I) and 26 had more than six teeth missing (Group II), except for the third molars,. The missing teeth and dental anomalies were examined clinically and radiographically. The MSX1 gene was sequenced from the blood samples of patients who consented to the study. Results: Mutations or polymorphisms on the MSX1 gene were identified in six patients. Taurodontism was seen in patients from both groups I and II. The nucleotide changes were identified by mutation screening. Conclusions: Performing family studies, screening other candidate genes, and investigation of interactions between genes will provide a basis for better analysis of tooth agenesis models and their association with other dental anomalies.
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Affiliation(s)
- Derya Ceyhan
- Department of Pediatric Dentistry, Faculty of Dentistry, Süleyman Demirel University, Isparta, Turkey
| | - Zuhal Kirzioglu
- Department of Pediatric Dentistry, Faculty of Dentistry, Süleyman Demirel University, Isparta, Turkey
| | - Nilufer Sahin Calapoglu
- Department of Medical Biology, Faculty of Medicine, Süleyman Demirel University, Isparta, Turkey
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Hassan DA, Abuaffan AH, Hashim HA. Prevalence of hypodontia in a sample of Sudanese orthodontic patients. J Orthod Sci 2014; 3:63-7. [PMID: 25143929 PMCID: PMC4138788 DOI: 10.4103/2278-0203.137683] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Objective: The aims of this study were to determine the prevalence of hypodontia in the permanent dentition in a sample of Sudanese patients who sought orthodontic treatment and to compare the results with the reported findings of other populations. Materials and Methods: Orthodontic files including orthopantomographs of 1069 patients (760 females and 309 males - more than 8 years old) were examined and inspected for evidence of hypodontia. Results: The prevalence of hypodontia of the present sample was 5.1%. Hypodontia was found considerably more frequently in the mandible than in the maxilla. The distribution of missing teeth was noticed in the left side more than in the right side. The most frequently missing teeth were the maxillary lateral incisors, followed by the mandibular second premolars, maxillary second premolars and mandibular left lateral incisor. The majority of patients had two or three teeth missing, but rarely more than 5 teeth missing. Conclusions: The prevalence of hypodontia of this study was within the range of that reported in the literature. The incidence of hypodontia in the anterior segment requires great need for orthodontic and prosthodontic treatment. With early detection of hypodontia, alternative treatment modalities can be planned and performed with a multidisciplinary team approach restoring the esthetic and function.
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Affiliation(s)
- Duaa Abdulrahman Hassan
- Hamad Medical Corporation, Rumaila Hospital Dental Centre, Orthodontic Division, Doha, Qatar
| | | | - Hayder A Hashim
- Hamad Medical Corporation, Rumaila Hospital Dental Centre, Orthodontic Division, Doha, Qatar
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Lee HS, Kim SH, Kim SO, Lee JH, Choi HJ, Jung HS, Song JS. A new type of dental anomaly: molar-incisor malformation (MIM). Oral Surg Oral Med Oral Pathol Oral Radiol 2014; 118:101-109.e3. [DOI: 10.1016/j.oooo.2014.03.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Revised: 03/07/2014] [Accepted: 03/12/2014] [Indexed: 10/25/2022]
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Kjær I. Mechanism of human tooth eruption: review article including a new theory for future studies on the eruption process. SCIENTIFICA 2014; 2014:341905. [PMID: 24688798 PMCID: PMC3944225 DOI: 10.1155/2014/341905] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Accepted: 12/24/2013] [Indexed: 06/03/2023]
Abstract
Human eruption is a unique developmental process in the organism. The aetiology or the mechanism behind eruption has never been fully understood and the scientific literature in the field is extremely sparse. Human and animal tissues provide different possibilities for eruption analyses, briefly discussed in the introduction. Human studies, mainly clinical and radiological, have focused on normal eruption and gender differences. Why a tooth begins eruption and what enables it to move eruptively and later to end these eruptive movements is not known. Pathological eruption courses contribute to insight into the aetiology behind eruption. A new theory on the eruption mechanism is presented. Accordingly, the mechanism of eruption depends on the correlation between space in the eruption course, created by the crown follicle, eruption pressure triggered by innervation in the apical root membrane, and the ability of the periodontal ligament to adapt to eruptive movements. Animal studies and studies on normal and pathological eruption in humans can support and explain different aspects in the new theory. The eruption mechanism still needs elucidation and the paper recommends that future research on eruption keeps this new theory in mind. Understanding the aetiology of the eruption process is necessary for treating deviant eruption courses.
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Affiliation(s)
- Inger Kjær
- Orthodontics Section, Department of Odontology, Faculty of Health and Medical Sciences, University of Copenhagen, 20 Nørre Allé, 2200 Copenhagen N, Denmark
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Jacobsen PE, Henriksen TB, Haubek D, Østergaard JR. Prenatal exposure to antiepileptic drugs and dental agenesis. PLoS One 2014; 9:e84420. [PMID: 24416231 PMCID: PMC3885552 DOI: 10.1371/journal.pone.0084420] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 11/14/2013] [Indexed: 12/25/2022] Open
Abstract
OBJECTIVE The aim of the study was to investigate the association between prenatal exposure to AEDs and the risk of dental agenesis and to differentiate between the possible effects of the different drugs used. METHODS Data on 214 exposed and 255 unexposed children, aged 12-18 years, were extracted from the Prescription Database of the Central Denmark Region and North Denmark Region and the Danish Medical Birth Registry. The children's dental charts were examined for the presence of dental agenesis. RESULTS Overall, children exposed to AED in utero had an increased risk of developing dental agenesis, but as a group, the difference was not significant (OR = 1.7; [95% CI: 0.8-3.6]). The risk of developing dental agenesis was three-fold increased (OR = 3.1; [95% CI: 1.3-7.4]) in children exposed to valproate in mono- or in poly-therapy with other AEDs than carbamazepine or oxcarbazepine. The risk was further increased (OR = 11.2; [95% CI: 2.4-51.9]) in children exposed to valproate and carbamazepine or oxcarbazepine in combination. CONCLUSIONS The present study shows that dental agenesis is a potential congenital abnormality that is related to prenatal exposure to valproate, and dental agenesis may be considered a sensitive marker for the teratogenicity of valproate.
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Affiliation(s)
- Pernille E. Jacobsen
- Section of Pediatric Dentistry, Department of Dentistry, Health, Aarhus University, Aarhus, Denmark
| | - Tine B. Henriksen
- Perinatal Epidemiology Research Unit, Department of Pediatrics, Aarhus Universty Hospital, Aarhus, Denmark
| | - Dorte Haubek
- Section of Pediatric Dentistry, Department of Dentistry, Health, Aarhus University, Aarhus, Denmark
| | - John R. Østergaard
- Center for Rare Diseases, Department of Pediatrics, Aarhus University Hospital, Aarhus, Denmark
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Aesthetic rehabilitation of oligodontia in primary dentition with adhesive partial denture. Case Rep Dent 2013; 2013:872476. [PMID: 24319602 PMCID: PMC3835716 DOI: 10.1155/2013/872476] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 09/25/2013] [Indexed: 11/17/2022] Open
Abstract
The primary teeth are essential for bone development and establishment of the arches on occlusion. Thus, the congenitally absence of teeth may trigger a shift in the balance of the occlusion, promoting disharmony in the structures of the maxilla-mandibular system. However, some interventions are possible to be performed in these cases even in pediatric patients, to redirect growth, preventing growth deviations and reestablishing the aesthetic. The aim of this paper is to report the treatment of a 4-year-old child presenting congenitally absence of mandibular central and lateral incisors and maxilla lateral incisors, which consequently compromises aesthetics, occlusal function, and the development and the functional growth of the bones. The oral rehabilitation was performed with an adhesive partial denture, which was able to restore the aesthetic and the occlusal function, therefore being a viable alternative in the treatment of this patient of little age.
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Andersson EMM, Axelsson S, Austeng ME, Overland B, Valen IE, Jensen TA, Akre H. Bilateral hypodontia is more common than unilateral hypodontia in children with Down syndrome: a prospective population-based study. Eur J Orthod 2013; 36:414-8. [DOI: 10.1093/ejo/cjt063] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Riis LC, Kjær I, Mølsted K. Dental anomalies in different cleft groups related to neural crest developmental fields contributes to the understanding of cleft aetiology. J Plast Surg Hand Surg 2013; 48:126-31. [DOI: 10.3109/2000656x.2013.831767] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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Kenrad JB, Christensen IJ, Kjær I. Gender differences in patterns of second premolar agenesis observed in 4,756 individuals. Eur Arch Paediatr Dent 2013; 14:397-403. [DOI: 10.1007/s40368-013-0041-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Accepted: 04/13/2013] [Indexed: 12/22/2022]
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Abstract
OBJECTIVE To evaluate and compare the sizes of teeth in mild and severe hypodontia patients with those of healthy controls. MATERIALS AND METHODS Dental casts of 154 patients with two or more congenitally missing teeth were obtained. Patients were divided into two groups according to severity of hypodontia. Group I (mild) consisted of 118 patients with two to five missing teeth. Group II (severe) consisted of 36 patients with six or more missing teeth. In addition, a control group was included, which consisted of 50 patients who had an Angle Class I jaw relationship and no missing teeth. Mesiodistal and labiolingual dimensions of the teeth were measured with a digital caliper on dental casts. The independent-samples t-test was used to evaluate the effect of gender on measurements. Intergroup differences for mesiodistal and labiolingual dimensions were evaluated with analysis of variance and post hoc Tukey tests. RESULTS Statistically significant differences were found between girls and boys with hypodontia in the mesiodistal dimension of the mandibular first premolar and the labiolingual dimension of the mandibular lateral incisor (P < .01). Mesiodistal and labiolingual width measurements of the teeth of hypodontia patients showed statistically significant differences compared with the control group (P < .05). Most teeth showed significant dimensional reductions in severe hypodontia compared with mild hypodontia (P < .05). CONCLUSIONS The mesiodistal and labiolingual dimensions of teeth in both mild and severe hypodontia groups were smaller than those in control subjects. The reduction in size was more excessive in the severe hypodontia group. The teeth showing the greatest difference in tooth dimensions were the maxillary lateral incisor (in mesiodistal dimension) and the mandibular canine (labiolingual dimension).
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Affiliation(s)
- Ahmet Yalcin Gungor
- Department of Orthodontics, Faculty of Dentistry, University of Akdeniz, Antalya, Turkey.
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29
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Pegelow M, Alqadi N, Karsten ALA. The prevalence of various dental characteristics in the primary and mixed dentition in patients born with non-syndromic unilateral cleft lip with or without cleft palate. Eur J Orthod 2011; 34:561-70. [DOI: 10.1093/ejo/cjr074] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Bilateral asymmetry of tooth formation is elevated in children with simple hypodontia. Arch Oral Biol 2011; 56:687-94. [DOI: 10.1016/j.archoralbio.2010.12.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Revised: 11/23/2010] [Accepted: 12/01/2010] [Indexed: 11/22/2022]
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Kjaer I. Orthodontics and foetal pathology: a personal view on craniofacial patterning. Eur J Orthod 2009; 32:140-7. [PMID: 19635743 DOI: 10.1093/ejo/cjp059] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
This article summarizes the essentials of studies on the craniofacial skeleton performed over 17 years. It presents data from research into foetal pathology resulting in new views on craniofacial patterning and/or fields for further discussion. The fields described cover all areas seen on profile, frontal, and panoramic radiographs. The fields are the theca, frontonasal, maxillary, palatine, and mandibular together with the cerebellar field and cervical spine. Regional fields in the dentition are described according to the pattern of peripheral nerve innervation. Studies on severely malformed foetuses show that the malformation can occur solely within a single field or in several fields. This is the background for these personal views on craniofacial patterning. These new views may assist in the diagnosis and interpretation of malformations in the cranium and dentition.
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Affiliation(s)
- Inger Kjaer
- Department of Orthodontics, School of Dentistry, Faculty of Health Sciences, University of Copenhagen, Denmark.
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Kær I. Can the location of tooth agenesis and the location of initial bone loss seen in juvenile periodontitis be explained by neural developmental fields in the jaws? Acta Odontol Scand 2009. [DOI: 10.3109/00016359709091945] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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De Coster PJ, Marks LA, Martens LC, Huysseune A. Dental agenesis: genetic and clinical perspectives. J Oral Pathol Med 2008; 38:1-17. [PMID: 18771513 DOI: 10.1111/j.1600-0714.2008.00699.x] [Citation(s) in RCA: 159] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Dental agenesis is the most common developmental anomaly in humans and is frequently associated with several other oral abnormalities. Whereas the incidence of missing teeth may vary considerably depending on dentition, gender, and demographic or geographic profiles, distinct patterns of agenesis have been detected in the permanent dentition. These frequently involve the last teeth of a class to develop (I2, P2, M3) suggesting a possible link with evolutionary trends. Hypodontia can either occur as an isolated condition (non-syndromic hypodontia) involving one (80% of cases), a few (less than 10%) or many teeth (less than 1%), or can be associated with a systemic condition or syndrome (syndromic hypodontia), essentially reflecting the genetically and phenotypically heterogeneity of the condition. Based on our present knowledge of genes and transcription factors that are involved in tooth development, it is assumed that different phenotypic forms are caused by different genes involving different interacting molecular pathways, providing an explanation not only for the wide variety in agenesis patterns but also for associations of dental agenesis with other oral anomalies. At present, the list of genes involved in human non-syndromic hypodontia includes not only those encoding a signaling molecule (TGFA) and transcription factors (MSX1 and PAX9) that play critical roles during early craniofacial development, but also genes coding for a protein involved in canonical Wnt signaling (AXIN2), and a transmembrane receptor of fibroblast growth factors (FGFR1). Our objective was to review the current literature on the molecular mechanisms that are responsible for selective dental agenesis in humans and to present a detailed overview of syndromes with hypodontia and their causative genes. These new perspectives and future challenges in the field of identification of possible candidate genes involved in dental agenesis are discussed.
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Affiliation(s)
- P J De Coster
- Department of Paediatric Dentistry and Special Care, Paecamed Research, Ghent University, Ghent, Belgium.
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Yamaguchi T, Tomoyasu Y, Nakadate T, Oguchi K, Maki K. Allergy as a possible predisposing factor for hypodontia. Eur J Orthod 2008; 30:641-4. [PMID: 18687988 DOI: 10.1093/ejo/cjn043] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The aim of this retrospective study was to identify general health problems as potential predisposing factors for hypodontia in a population of Japanese orthodontic patients. The study included 3683 individuals (1312 males and 2371 females, 13-42 years of age; mean, 23 years 7 months). Dental pantomograms (DPTs) were used to diagnose hypodontia. Health histories were obtained through a questionnaire administered by the dentist in charge. The Mantel-Haenszel test was used to determine the significance of the differences in the prevalence of health problems. The overall frequency of hypodontia was 5.8 per cent. The average number of missing teeth per patient was 1.7. There was a high prevalence of systemic complications, which included allergy, asthma, atopy, and enlarged adenoids associated with hypodontia. Only allergy showed a significant relationship with hypodontia (P < 0.01). The environmental aetiology of hypodontia is not yet fully understood. However, based on the results of this retrospective study, predisposing general health problems, especially allergy, seem to be involved.
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Kjaer I, Nielsen MH, Skovgaard LT. Can persistence of primary molars be predicted in subjects with multiple tooth agenesis? Eur J Orthod 2008; 30:249-53. [DOI: 10.1093/ejo/cjm123] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Swinnen S, Bailleul-Forestier I, Arte S, Nieminen P, Devriendt K, Carels C. Investigating the etiology of multiple tooth agenesis in three sisters with severe oligodontia. Orthod Craniofac Res 2008; 11:24-31. [PMID: 18199077 DOI: 10.1111/j.1601-6343.2008.00410.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVES To describe the dentofacial phenotypes of three sisters with severe non-syndromic oligodontia, to report on the mutation analysis in three genes, previously shown to cause various phenotypes of non-syndromic oligodontia and in two other suspected genes. Based on the phenotypes in the pedigree of this family, the different possible patterns of transmission are discussed. METHODS Anamnestic data and a panoramic radiograph were taken to study the phenotype of the three sisters and their first-degree relatives. Blood samples were also taken to obtain their karyotypes and DNA samples. Mutational screening was performed for the MSX1, PAX9, AXIN2, DLX1 and DLX2 genes. RESULTS The probands' pedigree showed evidence for a recessive or multifactorial inheritance pattern. Normal chromosomal karyotypes were found and - despite the severe oligodontia present in all three sisters - no mutation appeared to be present in the five genes studied so far in these patients. CONCLUSIONS In the three sisters reported, their common oligodontia phenotype is not caused by mutations in the coding regions of MSX1, PAX9, AXIN2, DLX1 or DLX2 genes, but genetic factors most probably play a role as all three sisters were affected. Environmental and epigenetic factors as well as genes regulating odontogenesis need further in vivo and in vitro investigation to explain the phenotypic heterogeneity and to increase our understanding of the odontogenic processes.
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Affiliation(s)
- S Swinnen
- Department of Orthodontics, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Catholic University Leuven, Leuven, Belgium
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Suri S, Ross RB, Tompson BD. Mandibular morphology and growth with and without hypodontia in subjects with Pierre Robin sequence. Am J Orthod Dentofacial Orthop 2006; 130:37-46. [PMID: 16849070 DOI: 10.1016/j.ajodo.2005.09.026] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2005] [Revised: 08/25/2005] [Accepted: 09/01/2005] [Indexed: 11/25/2022]
Abstract
INTRODUCTION Mandibular micrognathia is the hallmark of Pierre Robin sequence (PRS). A high prevalence of mandibular hypodontia has been reported in subjects with PRS. The hypothesis of this study is that the morphology of the mandible in subjects with PRS and mandibular hypodontia is different from that in subjects with PRS but without mandibular hypodontia. METHODS The study was conducted at the craniofacial center of The Hospital for Sick Children in Toronto. The study sample comprised 16 caucasian children with nonsyndromic PRS (7 boys, 9 girls) with mandibular hypodontia and 18 white children with nonsyndromic PRS (6 boys, 12 girls) without hypodontia. Longitudinal lateral cephalograms were available before orthodontic treatment (T1; mean age, 11.7 years) and after orthodontic treatment but before orthognathic surgery (T2; mean age, 16.6 years). A new, customized cephalometric analysis with additional landmarks and measurements to study mandibular morphology was performed. Differences in measurements were studied by using analysis of variance adjusted for age and sex. RESULTS Cephalometric measurements were smaller in the group with mandibular hypodontia at T1: mandibular length (3.36 mm, P = .04), ramal length (2.78 mm, P = .04), posterior facial height (3.97 mm, P = .03), and mandibular molar eruption (1.96 mm, P = .02). At T2, the differences increased: mandibular length (4.56 mm, P = .02), ramal length (4.04 mm, P = .002), posterior facial height (5.98 mm, P = .001), and mandibular molar eruption (2.08 mm, P = .04). Comparison of growth increments between the 2 groups from T1 to T2 showed a greater cranial base deflection increment in the group with mandibular hypodontia (0.88 degrees, P = .02) and a larger posterior facial height increment in the group without mandibular hypodontia (2.02 mm, P = .04). CONCLUSIONS Children with nonsyndromic PRS with mandibular hypodontia had smaller mandibles than children with nonsyndromic PRS and normal complements of mandibular teeth. Their patterns of growth did not improve during adolescence, and the magnitude of differences increased.
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Affiliation(s)
- Sunjay Suri
- Division of Orthodontics, Oral Health Sciences Center, Postgraduate Institute of Medical Education and Research, Chandigarh, 160012,
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Polder BJ, Van't Hof MA, Van der Linden FPGM, Kuijpers-Jagtman AM. A meta-analysis of the prevalence of dental agenesis of permanent teeth. Community Dent Oral Epidemiol 2004; 32:217-26. [PMID: 15151692 DOI: 10.1111/j.1600-0528.2004.00158.x] [Citation(s) in RCA: 565] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To gain more insight into the prevalence of dental agenesis. METHODS Data from Caucasian populations in North America, Australia and Europe were included in a meta-analysis. For the prevalence of African American, Chinese and Arab groups only indications could be reported because of a limited number of studies. RESULTS Agenesis differs by continent and gender: the prevalence for both sexes was higher in Europe (males 4.6%; females 6.3%) and Australia (males 5.5%; females 7.6%) than for North American Caucasians (males 3.2%; females 4.6%). In addition, the prevalence of dental agenesis in females was 1.37 times higher than in males. The mandibular second premolar was the most affected tooth, followed by the maxillary lateral incisor and the maxillary second premolar. The occurrence of dental agenesis was divided into three main groups: common (P2(i) > I2(s) > P2(s)), less common (I1(i) > I2(i) & P1(s) > C(s) & M2(i)) and rare (M2(s) & M1(s) > C(i) > M1(i) & I1(s)). Unilateral occurrence of dental agenesis is more common than bilateral occurrence. However, bilateral agenesis of maxillary lateral incisors is more common than unilateral agenesis. The overall prevalence of agenesis in the maxilla is comparable with that in the mandible, but a marked difference was found between both jaws regarding tooth type. Absence of one or two permanent teeth is found in 83% of the subjects with dental agenesis. A practical application of the results of the meta-analysis is the estimation of dental treatment need.
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Affiliation(s)
- Bart J Polder
- Department of Orthodontics and Oral Biology, University Medical Centre Sint Radboud, PO Box 9101, 6500 HB Nijmegen, The Netherlands.
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Mraiwa N, Jacobs R, van Steenberghe D, Quirynen M. Clinical Assessment and Surgical Implications of Anatomic Challenges in the Anterior Mandible. Clin Implant Dent Relat Res 2003; 5:219-25. [PMID: 15127992 DOI: 10.1111/j.1708-8208.2003.tb00204.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACKGROUND The anterior mandible is generally considered a rather safe surgical area, involving few risks of damage to vital anatomic structures. Nevertheless, both neurosensory disturbances and hemorrhages have been reported after implant surgery in that particular area. PURPOSE With the increasing demand for oral implant placement, the anatomy of the anterior mandible should receive more attention. This review will focus on the anatomic peculiarities of the anterior mandible and the related clinical implications. METHODS The scientific evidence on the anatomic, histologic, physiologic, and clinical aspects of the neurovascularization of the anterior mandible will be reviewed. RESULTS Surgical complications may be attributed to the existence of a mandibular incisive canal with a true neurovascular supply. Potential risks may also be related to the presence of the lingual foramen and anatomic variations, such as an anterior looping of the mental nerve. CONCLUSIONS Preoperative radiographic planning for oral implant placement in the anterior mandible should therefore not only consider all esthetic and functional demands but should also pay particular attention to the anatomic peculiarities of this region to avoid any neurovascular complications.
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Affiliation(s)
- Nuri Mraiwa
- Department of Periodontology, School of Dentistry, Oral Pathology and Maxillo-Facial Surgery, Faculty of Medicine, Catholic University of Leuven, Leuven, Belgium
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Abstract
The frequency, gender, and maxillary/mandibular occurrences of third molar agenesis have been studied in a Danish population of Down syndrome individuals (39 F and 31 M). The study was based on radiological examination and compared with 2 control groups of normal Caucasian populations. We found that the occurrence of third molar agenesis in Down syndrome individuals was around 4 times greater than in a normal population and higher than in corresponding previous studies. The agenesis occurred more often in the maxilla than in the mandible, and the frequency was not significantly higher in females than in males. The present study stresses the importance of focusing on the dental germs in the phenotypic discussion, as different genes are involved in tooth formation. The absence of teeth can contribute to an understanding of the interaction between genotype and phenotype.
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Affiliation(s)
- Jens Fog Lomholt
- Department of Orthodontics, School of Dentistry, Faculty of Health Sciences, University of Copenhagen, Denmark
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Kjær I, Hansen N, Becktor KB, Birkebæk N, Balslev T. Craniofacial Morphology, Dentition, and Skeletal Maturity in Four Siblings With Seckel Syndrome. Cleft Palate Craniofac J 2001. [DOI: 10.1597/1545-1569(2001)038<0645:cmdasm>2.0.co;2] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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Kjaer I, Hansen N, Becktor KB, Birkebaek N, Balslev T. Craniofacial morphology, dentition, and skeletal maturity in four siblings with Seckel syndrome. Cleft Palate Craniofac J 2001; 38:645-51. [PMID: 11681999 DOI: 10.1597/1545-1569_2001_038_0645_cmdasm_2.0.co_2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVE To describe the craniofacial morphology, dentition, and hand maturity in four siblings with Seckel syndrome. PATIENTS Two boys and two girls, with Seckel syndrome. The children studied showed extreme growth retardation, severe microcephaly, bird-headed profile with receding chin, prominent nose, mental retardation, and extremely delayed skeletal maturation. The growth hormone axis and pituitary thyroid function was normal. METHODS Skeletal and dental development were investigated from radiographic material, and a cephalometric analysis was performed from profile radiographs. RESULTS The craniums were remarkably small with an extremely short anterior cranial base (-4.3 to -5.5 standard units) and maxillary length (-3.8 to -4.7 SU). Differences in the morphology of the sella turcica were observed in girls and boys. Tooth maturity progressed normally. Tooth agenesis and tooth malformations were observed. Taurodontic root morphology was observed only in the girls. The approximate skeletal maturity showed retardation from 4 years 3 months to 4 years 11 months. Malformations of the hand-wrist skeleton occurred in the epiphyseal ossification centers of the middle phalangeal bone in the second, third, and fourth finger and in the distal phalangeal bone in the fifth finger. The epiphyseal ossification centers were lacking in the middle and distal phalangeal bones of the fifth finger. CONCLUSION The underlying gene defect in the affected children seemingly affects bone development and growth but not dental maturation and eruption.
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Affiliation(s)
- I Kjaer
- Department of Orthodontics, Faculty of Health Sciences, University of Copenhagen, Nørre Allé 20, DK-2000 Copenhagen, Denmark.
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Abstract
OBJECTIVES To establish the prevalence of numerical and morphological variations of permanent teeth in Swedish 7-year-olds and to accept or reject the hypothesis of a higher prevalence for these conditions in northern Sweden compared to other areas. DESIGN Cross-sectional. SETTING Department of Odontology/Pedodontics, Umeå University, Sweden. SAMPLE AND METHODS A total of 739 healthy Caucasian 7-year-olds residing in the city of Umeå, northern Sweden in 1976. The children were examined clinically and radiographically. RESULTS The prevalence of hypodontia (excluding third molars) in girls was 8.4%, in boys 6.5%, and in both sexes combined 7.4%. Of the children with hypodontia, the majority (90.9%) lacked one or two teeth. Lower second premolars were the teeth most frequently missing. The prevalence of hyperdontia was 1.9%; 11 girls and three boys were affected; 78% of the supernumerary teeth were mesiodenses. Of the morphological variations, peg-shaped upper lateral incisors were found in 0.8% of the children, double-formation (gemination) in 0.3%, taurodontism in 0.3% and dens invaginatus in 6.8%. One diagnosis was found in 18% of the children, and in almost 8% of them more than one diagnosis was found. CONCLUSIONS The results agree with those obtained in similar populations and are considered representative of this ethnic group. The hypothesis of a genetically determined higher prevalence of numerical and morphological variations in the study population was not verified.
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Affiliation(s)
- B Bäckman
- Faculty of Medicine and Odontology, Department of Odontology, Pedodontics, Umeå University, S-901 87 Umeå, Sweden.
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Kjaer I, Bagheri A. Prenatal development of the alveolar bone of human deciduous incisors and canines. J Dent Res 1999; 78:667-72. [PMID: 10029465 DOI: 10.1177/00220345990780020601] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The formation of the human alveolar process around the incisors and canines is a hitherto unreported aspect of fetal oral development. The question is how, where, and when the alveolar process is formed. The purpose of this study was to elucidate the questions where and when and hence to analyze the pattern of formation of the alveolar bone around developing human deciduous canine and incisor teeth. The study was conducted with material selected from a sample of 61 normal human fetuses, legally or spontaneously aborted. Fertilization ages ranged from 9 to 22 weeks, crown-rump Length from 25 to 205 mm, and foot length from 4 to 34 mm. From this material, 7 maxillae and 10 mandibles were selected for the study according to developmental stages of the canines and incisors and according to the orientation of the histological sections. The skeletal investigation consisted of macroscopic and microscopic analysis of the mandibles and maxillae. The investigations revealed the absence of bone between the central and lateral incisors in the mandibles and maxillae of fetuses below the ages of 21 and 22 weeks, respectively. In three specimens, alveolar bone between the central and lateral incisors was recorded (21, 21, and 22 weeks of fertilization). Absence of bone labial to the canine was recorded in all fetuses investigated. In all other regions, alveolar bone occurred as a regular finding. The present study has shown that alveolar bone formation is strictly coordinated with tooth formation. Alveolar bone occurs later in the area labial to the canine and in the region between the central and lateral incisors than it does in other areas associated with the incisor/canine regions. Knowledge of this pattern in the formation of the alveolar process seems to be of importance for a future elucidation of how the alveolar process is initially formed.
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Affiliation(s)
- I Kjaer
- Department of Orthodontics, School of Dentistry, Faculty of Health Sciences, University of Copenhagen, Denmark
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Abstract
The interrelation between the development of the brain/peripheral nerves and that of the surrounding bone tissue is termed neuro-osteology. In orthodontic and pediatric practice the development of the hard tissues is evaluated radiographically, but the development of the neural tissue within the bone tissue is not evaluated. In this review the emphasis is placed on two neuro-osteologic interrelations that can be observed on profile radiographs and orthopantomograms, respectively. One is the connection between the pituitary gland of the central nervous system and the sella turcica (profile radiograph), and the other is the association between the peripheral nerves and the development of the dentition (orthopantomogram). Pituitary gland/sella turcica: The correlation between prenatal malformation in the pituitary gland/sella turcica and the postnatal morphology of the sella turcica in holoprosencephaly, spina bifida/myelomeningocele, and cri-du-chat syndrome is demonstrated. Peripheral nerves/dentition: The prenatal innervation of the dentition is presented. Agenesis and tooth malformation occur in constant patterns within the dental arch fields that share the same innervation. The findings demonstrate that in postnatal diagnosis of the cranium and the teeth, traces of prenatal aberrations can be found that are important for neurofacial growth.
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Affiliation(s)
- I Kjaer
- Department of Orthodontics, School of Dentistry, Faculty of Health Sciences, University of Copenhagen, Denmark
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Kjaer I. Neuro-osteology. CRITICAL REVIEWS IN ORAL BIOLOGY AND MEDICINE : AN OFFICIAL PUBLICATION OF THE AMERICAN ASSOCIATION OF ORAL BIOLOGISTS 1998; 9:224-44. [PMID: 9603237 DOI: 10.1177/10454411980090020501] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Neuro-osteology stresses the biological connection during development between nerve and hard tissues. It is a perspective that has developed since associations were first described between pre-natal peripheral nerve tissue and initial osseous bone formation in the craniofacial skeleton (Kjaer, 1990a). In this review, the normal connection between the central nervous system and the axial skeleton and between the peripheral nervous system and jaw formation are first discussed. The early central nervous system (the neural tube) and the axial skeleton from the lumbosacral region to the sella turcica forms a unit, since both types of tissue are developmentally dependent upon the notochord. In different neurological disorders, the axial skeleton, including the pituitary gland, is malformed in different ways along the original course of the notochord. Anterior to the pituitary gland/sella turcica region, the craniofacial skeleton develops from prechordal cartilage, invading mesoderm and neural crest cells. Also, abnormal development in the craniofacial region, such as tooth agenesis, is analyzed neuro-osteologically. Results from pre-natal investigations provide information on the post-natal diagnosis of children with congenital developmental disorders in the central nervous system. Examples of these are myelomeningocele and holoprosencephaly. Three steps are important in clinical neuro-osteology: (1) clinical definition of the region of an osseous or dental malformation, (2) embryological determination of the origin of that region and recollection of which neurological structure has developed from the same region, and (3) clinical diagnosis of this neurological structure. If neurological malformation is the first symptom, step 2 results in the determination of the osseous region involved, which in step 3 is analyzed clinically. The relevance of future neuro-osteological diagnostics is emphasized.
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Affiliation(s)
- I Kjaer
- Department of Orthodontics, School of Dentistry, Faculty of Health Sciences, University of Copenhagen, Denmark
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Abstract
The purpose of this study was to examine radiographs of a large sample of children who had congenital absence of primary teeth and to determine the number and distribution of the missing teeth. Radiographs collected within the Danish Municipal Child Oral Health Care System were available of 193 children, all of whom had congenital absence of one or more primary teeth but no other abnormalities in the jaws or dentition. More than half of the children (54.9%) had agenesis of only one primary tooth, and 7.8% of more than two primary teeth. Agenesis was found twice as frequently in the maxillary lateral incisor region (119 children) than in the mandibular lateral incisor region (53 children). Congenital absence of primary molars, canines and maxillary central incisors was extremely rare. However, agenesis of one maxillary primary central incisor was found in two cases. A follow-up study will compare the agenesis patterns recorded with the pattern of agenesis in the permanent dentition of the same group of children.
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Affiliation(s)
- J Daugaard-Jensen
- Department of Paediatric Dentistry, University of Copenhagen, Denmark
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Chávez-Lomeli ME, Mansilla Lory J, Pompa JA, Kjaer I. The human mandibular canal arises from three separate canals innervating different tooth groups. J Dent Res 1996; 75:1540-4. [PMID: 8906121 DOI: 10.1177/00220345960750080401] [Citation(s) in RCA: 105] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The purpose of this study was to describe the prenatal formation of the human mandibular canal. Since bony canals develop in prenatal life around the nerve paths, it was assumed that the canal pattern could reflect the pattern of innervation of the dentition. Mapping of this early canal pattern does not appear to have been undertaken before. The material consisted of anthropological mandibles from the National Institute of Anthropology and History, Mexico City. A total of 302 human hemimandibles from the latter half of the prenatal period was investigated. The length, measured from the mental symphysis to the mandibular condyle, ranged from 28 to 60 mm. The dento-alveolar maturity was classified in two stages according to the appearance of alveolar sockets of deciduous and first permanent molars. The mandibles were radiographed with guttapercha points inserted into the canal openings (foramina) on the lingual surfaces of the mandibular rami. The study showed that the canal to the incisors appeared first, followed by the canal to the primary molars, and last by the one or more canals to the first permanent molars. In the most mature group, three different canals always occurred in each hemimandible. The canals were directed from the lingual surface of the mandibular ramus toward the different tooth groups. The inferior alveolar nerve presumably occurs in the mandible as three individual nerve paths originating at different stages of development. It is suggested that rapid prenatal growth and remodeling in the ramus region result in a gradual coalescence of the canal entrances that is obvious at birth. It is hypothesized that the pattern of tooth agenesis within the three groups of teeth is related to the three separate paths of innervation of the dentition.
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Affiliation(s)
- M E Chávez-Lomeli
- Center for Craniofacial Biology, Latin American University, Mexico City, Mexico
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Kjaer I. Human prenatal craniofacial development related to brain development under normal and pathologic conditions. Acta Odontol Scand 1995; 53:135-43. [PMID: 7572088 DOI: 10.3109/00016359509005963] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A survey is given of current knowledge of the interrelationship between facial, cranial and brain development in humans. First, normal facial, cranial (mandible, maxilla, palatine bone, cranial base, theca cranii, dentition), and brain development are described separately. Then, developmental interrelationships are illustrated under normal and pathologic conditions (cleft lip and palate, holoprosencephaly, anencephaly, amniotic band sequence). New observations are described in detail, and references are given to previously published articles. A close interconnection exists between the development of the face, the craniofacial skeleton, and the brain. This is illustrated by new observations in cleft palate fetuses and new theories about the etiology of holoprosencephaly and tooth agenesis. The survey focuses, moreover, on the importance of the face and the cranial base in endocrine development. Borderlines between face regions and cranial regions with different developmental origin are set up for future elucidation of the etiology behind syndromes involving the craniofacial regions.
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Affiliation(s)
- I Kjaer
- Department of Orthodontics, School of Dentistry, Faculty of Health Sciences, University of Copenhagen, Denmark
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