Rabilitação protética de indivíduos maxilectomizados com prótese obturadora: análise pelo método de elementos finitos e revisão sistemática

Abstract

The obturator prosthesis (OP) allows the restoration of speech, aesthetics, and oral function in patients with maxilectomized individuals. The objectives of the study were: 1. to evaluate, using the finite element analysis (FEA) methodology, the biomechanical behavior of metallic infrastructures of removable partial denture obturator (RPDO) for a maxilla with Aramany Class II resection, varying the type of major connector; 2. carry out a systematic review with network meta-analysis on the effectiveness of the OP and other treatments on the quality of life of its users. In the first study, a virtual model simulating an Aramany Class II maxilla with bone resection on the maxillary left side and absence of teeth 24, 25, 26 and 27 was developed using the Rhinoceros® 7.0 program based on two tomography scans. After obtaining the virtual model, three infrastructures digital RPDOs were created varying the type of major connector: major connector with reduced coverage (RPDO1), major connector with extensive coverage (RPDO2) and major connector with anteroposterior bar (RPDO3). The FEA analysis was carried out using the Optistruct 2022 software, and the results were analyzed using the HyperView 2022 software. The results were evaluated qualitatively through visual observation of graphic images with variation of color gradients according to the stress distribution and quantitative von Mises stress (σVM), maximum principal stress (σmax), minimum principal stress (σmin) and displacement (mm). For the second study, the systematic review with network meta-analysis (PROSPERO #CRD42023430827). Randomized controlled trials (RCTs) and non-randomized studies of intervention (NRSIs) with obturator prosthesis as one of the treatments were included. Seven patient-reported outcomes were analyzed separately for each study design, according to the QOL questionnaires: appearance, chewing, pain, social contact, speech, swallowing and general QOL. Data were converted to the UW-QOL v4 questionnaire, except social contact, which was converted to the EORTC QLQ-H&N35. Network meta-analysis (NMA) Bayesian random model was used to calculate mean differences (MD) and 95% credibility intervals (Crl) for each treatment comparison. Interpretation followed the certainty of evidence through the GRADE approach for NMA and the least important difference (DMI). The review included 4 RCTs and 9 NRSIs. Seven treatments were evaluated: presurgical (considered no treatment), surgical obturator, interim obturator, obturator, implant-supported obturator, magnet obturator, and flap, totaling 120 treatment comparisons in all seven outcomes. The results of the first study indicate that RPDO1 and RPDO3 showed similar behaviors, while RPDO2 presented the highest stress values for all system components. None of the groups presented significant displacement values. In the systematic review, it was observed that the effect estimates of some treatments reached the DMI, however, for all treatment comparisons, the credibility interval crossed the null effect line with very low certainty of evidence. No treatment showed superiority compared to another for any outcome. For both studies, further laboratory studies and RCTs are encouraged to confirm the evidence.