Evaluation and comparison of retention and patient satisfaction with milled polyetheretherketone versus metal maxillary obturators.

STATEMENT OF PROBLEM: Metal and polyetheretherketone (PEEK) have been used to rehabilitate maxillary defects with obturators, each having advantages and disadvantages. However, patient satisfaction with the obturator retention of each material is unclear. PURPOSE: The purpose of this crossover clinical study was to compare retention and patient satisfaction between a milled cobalt chromium and a milled PEEK framework, each with a hollow bulb extension in polymethyl methacrylate (PMMA). MATERIAL AND METHODS: Twenty patients who had received unilateral total maxillectomy and were treated in the prosthodontic department's maxillofacial clinic were enrolled in this crossover study. Each participant wore 2 different types of obturators for 6 months after insertion. Type CoCr received a milled cobalt chromium framework with a hollow bulb extension in PMMA first, and type Pk received a milled modified PEEK (BioHPP) framework with a hollow bulb extension in PMMA first. Patient satisfaction and retention force were measured immediately, at 3 months, and at 6 months after obturator insertions. The Fischer exact, chi-squared, and Monte Carlo tests were used to compare qualitative data. One-way ANOVA with the post hoc Tukey test was used for pair-wise comparison, and repeated measures ANOVA was used to compare before and after treatment at 3 and 6 months. RESULTS: No significant difference was found between types in obturator insertion (P>.999), appearance of the upper lip (P>.999), mouth feeling (P=.301), pronunciation of words (P=.217), and talking in public (P=.589). A significant difference between types was found in speech after 6 months of obturator insertion (P=.016), swallowing liquids and food (P=.04), masticating foods (P=.007), appearance of clasps on anterior teeth (P=.002), satisfaction with appearance (P=.005), or avoidance of family events (P=.014) after 6 months of insertion. Types of obturators showed a statistically significant decrease in retention force with time (P<.001). CONCLUSIONS: Although the retention force was less with PEEK than with Co-Cr clasps engaging the same undercuts, this retention force was adequate for retaining removable partial dentures. Co-Cr clasps can be considered better than PEEK clasps because they engage the same undercuts regarding loss of retention with time. Quality of life in patients after maxillary resection could be improved by using maxillary obturators. Type Pk was better than type CoCr in terms of esthetics, but the retention of the PEEK obturator after 6 months decreased because of wear, leading to difficulty swallowing food or liquids, mastication, and speech.

Peri-implant strain around mesially inclined two-implant-retained mandibular overdentures with Locator attachments.

This study aimed to evaluate the peri-implant strain around mesially inclined implants used to retain mandibular overdentures with Locator resilient attachments. Four mandibular edentulous acrylic resin models received two implants in the canine areas with 0°, 5°, 10°, and 20° mesial inclinations. Overdentures were connected to the implants using Locator attachments. Pink nylon inserts (light retention) were used for all implant inclinations, and red inserts were used for 20° inclination (20°red). Four strain gages were bonded on the mesial (M), distal (D), buccal (B), and lingual (L) surfaces of each implant. Peri-implant strains were measured during bilateral and unilateral loading. The 20° inclination showed the highest strain, followed by 10° and 5°, and both 0° and 20°red presented with the lowest strain. Site D was associated with the highest strain, followed by M, B, and L, which showed the lowest strain values. Unilateral loading and the loading side presented with significantly higher strain values than bilateral loading and the nonloading side, respectively. Hence, in this study, strains around the two-implant-retained overdentures with Locator attachments increased with increases in mesial implant angulation, except when red male inserts were used.

Effect of two designs of implant-supported overdentures on peri-implant and posterior mandibular bone resorptions: a 5-year prospective radiographic study.

OBJECTIVES: The aim of this study was to evaluate and compare the effect of two designs of implant-supported overdentures on peri-implant and posterior mandibular bone resorptions after 5 years of follow-up. MATERIALS AND METHODS: Twenty edentulous patients were randomly assigned into two equal groups: Group I (GI), patients received overdentures supported and retained by cantilevered bars on two canine implants and Group II (GII), patients received overdentures retained by straight bars on two canine implants and supported by two-first molar implants. Peri-implant vertical (VBL) and horizontal (HBLO) bone losses were assessed on periapical radiographs at the time of overdenture insertion (T0), 6 months (T6 m), 1 year (T1), 3 years (T3), and 5 years (T5) after insertion. Posterior mandibular bone resorption was evaluated using proportional measurements (posterior area index, PAI) made on panoramic radiographs at T0 and T5. RESULTS: Group I recorded significant higher VBL than GII. VBL increased significantly with advance of time in both groups. Posterior implant recorded significant higher VBL than anterior implants in GII. HBLO did not differ significantly between groups or between observation times. Group I recorded significant higher PAI than GII at T5. Group, age, and initial height of the mandibular ridge were significantly correlated with PAI. CONCLUSION: Within the limitations of this study, regarding the small sample size, it could be concluded that overdentures retained by straight bars on two canine implants and supported by two-first molar implants present a clinical advantage in terms of peri-implant and posterior mandibular bone preservation compared to overdentures supported and retained by cantilevered bars on two canine implants after 5 years.

Comparison of immediate complete denture, tooth and implant-supported overdenture on vertical dimension and muscle activity.

PURPOSE: To compare the changes in the occlusal vertical dimension, activity of masseter muscles and biting force after insertion of immediate denture constructed with conventional, tooth-supported and Implant-supported immediate mandibular complete denture. MATERIALS AND METHODS: Patients were selected and treatment was carried out with all the three different concepts i.e, immediate denture constructed with conventional (Group A), tooth-supported (Group B) and Implant-supported (Group C) immediate mandibular complete dentures. Parameters of evaluation and comparison were occlusal vertical dimension measured by radiograph (at three different time intervals), Masseter muscle electromyographic (EMG) measurement by EMG analysis (at three different positions of jaws) and bite force measured by force transducer (at two different time intervals). The obtained data were statistically analyzed by using ANOVA-F test at 5% level of significance. If the F test was significant, Least Significant Difference test was performed to test further significant differences between variables. RESULTS: Comparison between mean differences in occlusal vertical dimension for tested groups showed that it was only statistically significant at 1 year after immediate dentures insertion. Comparison between mean differences in wavelet packet coefficients of the electromyographic signals of masseter muscles for tested groups was not significant at rest position, but significant at initial contact position and maximum voluntary clench position. Comparison between mean differences in maximum biting force for tested groups was not statistically significant at 5% level of significance. CONCLUSION: Immediate complete overdentures whether tooth or implant supported prosthesis is recommended than totally mucosal supported prosthesis.