This study aimed to evaluate support (the resistance to tissue-ward movement) and strain distribution in unilateral obturators with four designs using Digital Image Correlation (DIC) and Finite Element Analysis (FEA). Twelve epoxy-resin models were prepared to receive removable obturators that have four designs, including acrylic resin-based obturators (ARO), linear (LDO), tripodal (TDO), and a newly modified one termed fully tripodal design obturator (FTDO) were used for DIC. The models were installed in a DIC set to receive a vertical load of 150N. The strain on the dentate and defect sides was evaluated using DIC software. Mathematically, four finite element models were prepared to receive vertical and lateral loads of 100N on two points. The support and strain were assessed using the ANSYS workbench. Using DIC, the ARO demonstrated the highest strain values on the defect area and as an entire prosthesis, followed by the LDO on the defect side. Using FEA, the TDO produced the highest strain value with anterior (oblique) and posterior loads. LDO produced the lowest support and highest strain on the anterior teeth compared to TDO and FTDO. ARO resulted in the highest total strain, while the TDO produced the lowest. Both TDO and FTDO were comparable in terms of strains and support.

Studies on the biomechanics of obturators in the currently used designs of Aramany class I defect are lacking. Also, modifications of the designs presently used in unilateral palatal defects are needed to produce a prosthesis with more retention and less stress on the abutments.

The purpose of part I of this study was to differentiate among Aramany class I obturators of 4 designs regarding retention and associated stress using numerical and experimental methods.

Four finite element models and 36 different base obturators were fabricated and divided into 9 acrylic resin bases retained with Adams clasps and 9 linear, 9 tripodal, and 9 fully tripodal design obturators from casts obtained from a scanned skull. After modification, the prostheses were fabricated on the casts obtained from a 3-dimensionally printed cast. The retention was evaluated, and the data were collected and analyzed using a statistical software program (α=.05). The displacement and associated stress in the assorted casts were compared by using 5-N displacing force at 3 points using finite element analysis. The quantitative assessment was made by measuring the displacement and von Mises stress distribution on the prostheses and their supporting structures. The qualitative analysis was done by using a visual color mapping to depict stress location and intensity.

No significant differences were found between fully tripodal (4.478 ±2.303 MPa) and tripodal obturators (4.478 ±2.286 MPa; P=.153), although fully tripodal showed more resistance to anterior displacement (4.522 ±0.979 and 3.553 ±1.58 MPa for fully tripodal and tripodal designs, respectively; P=.007), and tripodal obturators produced more resistance to middle displacement (5.441 ±1.778 and 2.784 ±0.432 MPa for tripodal and fully tripodal design respectively; P=.001). The fully tripodal obturator showed more retention (3.736 ±1.182 MPa) than the linear one (2.493 ±1.052 MPa; P=.001). The maxillary central incisor was the most stressed abutment, followed by the lateral incisor, while the second molar was the least.

Regarding retention, the fully tripodal obturator produces retention comparable with the tripodal and significantly more than the linear. Acrylic resin prostheses retained with Adams clasps may be similar to metal-based prostheses regarding retention and stress distribution on the supporting structures.

Oral rehabilitation of head and neck cancer patients is an integral component of the care pathway. Maxillectomy procedures can cause significant defects, such as oronasal fistulas, loss of support for the cheek and lip, aesthetic defects in the middle third of the face and functional impairments. Orofacial rehabilitation plays a fundamental role in restoring aesthetics and functional capabilities, such as speech, mastication and deglutition.Rehabilitation of maxillectomy patients poses a challenge for both clinicians and patients. This paper utilises case examples to demonstrate the treatment options for the oral rehabilitation of these patients. We will summarise the treatment pathways for conventional obturators, delayed (secondary) implant retained fixed rehabilitation following composite free flap and early rehabilitation using a zygomatic implant perforated flap technique. This paper aims to highlight the challenges in treatment planning and the importance of a multidisciplinary approach in improving patient outcomes.

This systematic review is aimed at investigating the biomechanical stress that develops in the maxillofacial prostheses (MFP) and supporting structures and methods to optimize it. Design and Methods. A literature survey was conducted for full-text English articles which used FEA to examine the stress developed in conventional and implant-assisted MFPs from January 2010 to December 2020.

87 articles were screened to get an update on the desired information. 74 were excluded based on a complete screening, and finally, 13 articles were recruited for complete reviewing. Discussion. The MFP is subjected to stress, which is reflected in the form of compressive and tensile strengths. The stress is mainly concentrated the resection line and around the apices of roots of teeth next to the defect. Diversity of designs and techniques were introduced to optimize the stress distribution, such as modification of the clasp design, using materials with different mechanical properties for dentures base and retainer, use of dental (DI) and/or zygomatic implants (ZI), and free flap reconstruction before prosthetic rehabilitation.

Using ZI in the defective side of the dentulous maxillary defect and defective and nondefective side of the edentulous maxillary defect was found more advantageous, in terms of compression and tensile stress and retention, when compared with DI and free flap reconstruction.

A surgical obturator may need to be modified during the healing process after tissue resection. Apart from relining the fitting surfaces to accommodate the healing wound and changes in the surrounding tissues, other modifications such as adding teeth are sometimes required to improve esthetics and speech. This article describes a chairside technique to add customized acrylic resin teeth to an existing surgical obturator.