Published online Jan 26, 2020. doi: 10.12998/wjcc.v8.i2.284
Peer-review started: September 23, 2019
First decision: December 4, 2019
Revised: December 17, 2019
Accepted: December 21, 2019
Article in press: December 21, 2019
Published online: January 26, 2020
Prevention of relapse of the dentition to their respective pretreatment positions plays an essential role in the success of orthodontic treatment. Rotated teeth are more susceptible to revert back toward their original positions after removal of the orthodontic appliances compared to teeth displaced in other directions. This might be due to the lack of reorganization and subsequent reorientation of the supra-crestal periodontal fibers and gingival fibers after tooth rotation and retention appear to be torn, ripped, disorganized, laterally spaced, and of increased diameter. Various procedures have been proposed in order to overcome this problem and to reduce this relapse, which include the circumferential supracrestal fiberotomy (CSF) procedure. Very few studies have examined the frequency of rotational relapse in relation to CSF.
There are only a few articles that have addressed the association between CSF and tooth rotation following orthodontic treatment. Few have measured the prevalence of rotational relapse following this approach. This information is essential for patients to understand outcome of treatment as well as to guide orthodontists in the proper management of cases requiring teeth rotation.
The purpose of this study was to assess the amount of relapse following the CSF of the orthodontically derotated anterior teeth and to find out if there is any potential effect of CSF in reducing rotational relapse by measuring the prevalence of relapse in post-CSF orthodontically derotated teeth.
Subjects were recruited who underwent derotational alignment of maxillary and mandibular anterior teeth during orthodontic treatment. The CSF surgery was performed after completion of orthodontic treatment and placement of a fixed retainer. Angles of the rotation correction and relapse were measured on three different set of casts obtained from the patients (pretreatment, post-treatment with retainer, and post-treatment with no retainer). Relapse percentage of each derotated tooth, which results as a post-treatment adverse outcome was calculated and determined from the post-treatment casts. Rotational relapse was categorized as follows: Unnoticeable relapse (0°), barely noticeable relapse (1°-3°), noticeable relapse (4°-9°), and clearly noticeable relapse (≥ 10°). The percent relapse that had occurred 1 year after teeth were aligned to their ideal position was calculated. Data were analyzed by dental arch type and tooth type. Wilcoxon test was used to determine if there were any significant differences between rotational degree angles.
Eleven subjects with a mean age of 23 years old and a total of 90 teeth were included. In regard to frequency of rotational relapse following CSF and retainer placement at the 12 mo follow-up assessment, 57.8% of the teeth maintained their corrected position, and no statistically significant relapse had occurred, which confirms the effectiveness of CSF. When relapse was evaluated and categorized among subjects, overall mean relapse was 1.1° (10.8%). More than half (n = 52, 57.8%) of teeth were categorized as having unnoticeable relapse (0°). Of the remaining teeth, 34.5% (n = 31) had barely noticeable relapse (1°-3°), 6.6% (n = 6) had noticeable relapse (4°-9°), and 1.1% (n = 1) had clearly noticeable relapse (≥ 10°). When analyzed by arch, 54.5% (n = 6) of the relapsed maxillary teeth had barely noticeable relapse (1°-3°), 37.5% (n = 3) of the mandibular teeth had noticeable relapse (4°-9°), and 12.5% (n = 1) had clearly noticeable relapse (≥ 10°).
Minimal amount of rotational relapse was shown after CSF surgery if used in conjunction with an adequate period of post-treatment retention. Thus, CSF surgery is a possible adjunctive treatment modality for minimizing the rotational relapse of the anterior teeth. Furthermore, rotational relapse was more frequent in the maxillary arch than in the mandibular arch. Approximately 42% of teeth showed some degree of rotational relapse. Only one tooth had clearly noticeable relapse (≥ 10°). Relapse was most frequent in the maxillary lateral incisors and mandibular canines. This can be essential when planning for orthodontic rotation of maxillary teeth as it might need an increased amount of rotation compared to mandibular. However, further studies with larger sample sizes and longer follow-up periods are needed to confirm this conclusion.
Identifying post orthodontic rotational relapseâs frequency following fibrotomy can aid in proper prognosis and decision-making or further orthodontic correction when needed. Future controlled studies with larger sample sizes and long follow-ups are warranted to evaluate the present findings.