Application of Polyvinyl chloride sheet as delayed surgical obturator in maxillectomy defects secondary to mucormycosis- A case series.

It was a great challenge for the prosthodontist to rehabilitate and sustain the prosthesis in patients with bilateral maxillectomy defects due to mucormycosis seen with Covid-19 during second wave in India. In such extensive defects there was difficulty in retaining the obturator due to the absence of soft tissue or anatomical undercuts, condition of existing dentition, retained inferior turbinates and limitation in taking retention from defect side during healing phase. In such extensive maxillectomy defects, retention, stability and support can be enhanced by maximum preservation of hard and soft tissues, skin grafting and removal of inferior turbinates to provide a larger surface area for stress distribution. But here, in this case series, maxillectomy defects with retained inferior turbinates presented a problem in retaining the obturator prosthesis due to limitation in taking retention from the defect side. The conventional method of fabrication of obturator using autopolymerizing acrylic failed in terms of weight of the prosthesis and in gaining retention from the defect side during healing phase. Therefore, thermoplastic vacuum pressed Polyvinyl chloride sheet (PVC) was used for fabrication of delayed surgical obturator due to many merits conferred by it. Its light weight, non porous nature, easy adaptability, patient comfort, efficient undercut engagement, hygienic nature makes it a good treatment option. The main cocern was to close oro-nasal communication to eliminate the need of nasogastric tube and to prevent nasal regurgitation. In all cases, patients were comfortable with the obturator prosthesis in terms of adaptation and function.

Comparative Evaluation of Load-Bearing Capacity and Fracture Analysis of PEEK and Zirconia Three-Unit Fixed Dental Prostheses: An In Vitro Study.

PURPOSE: The purpose of this exploratory in vitro study was to compare and evaluate the load-bearing capacity (LBC) of ceramic-veneered zirconia and composite-veneered polyetheretherketone (PEEK) three-unit fixed dental prostheses (FDPs) with and without thermocycling (TC). MATERIALS AND METHODS: The study included 40 samples of three-unit FDPs replacing mandibular first molars. The four groups included were: ceZIR (feldspathic ceramic-layered zirconia), ceZIR TC (feldspathic ceramic-layered thermocycled zirconia), cPEEK (composite-layered PEEK), and cPEEK TC (composite-layered thermocycled PEEK) (n = 10 per group). All frameworks were CAD/CAM milled. Ten PEEK and 10 zirconia samples were subjected to TC (6,000 cycles). All 40 FDP specimens were loaded by applying static load, using a universal testing machine. The maximum load required to fracture the specimens denoted the LBC. The comparison of LBC between the four groups was done by using two-way ANOVA with Tukey's post-hoc analysis (α = .05). RESULTS: There was no statistically significant difference between LBC of cPEEK and ceZIR (P > .001) without thermal aging. LBC values decreased considerably for thermally aged specimens. Statistically significant differences were observed between LBC of cPEEK TC and ceZIR TC (P < .001), cPEEK TC and cPEEK (P < .001), and ceZIR TC and ceZIR (P = .001). On fracture analysis, cPEEK showed delamination failures whereas ceZIR displayed catastrophic connector fractures. CONCLUSION: This comparative evaluation offers preliminary data highlighting substantial depreciation in the LBC of layered PEEK under simulated intraoral conditions, thus raising a question regarding the clinical longevity of layered PEEK multi-unit restorations. In contrast, feldspathic-layered zirconia can be suitable for use in posterior FDPs.

Role and influence of growth factors on early osseointegration in animal jaw bone: A meta-analysis.

AIM: Growth factors (GFs) are polypeptides, which are intricately involved in the regulation of bone formation, preservation, and regeneration through gene expression. However, the role of these bioactive agents in osseointegration of dental implants has not been substantially proven. The objective of this systematic review (SR) and meta-analysis was to explore the effect of GFs on early osseointegration of dental implants in animal jaws. An attempt to decipher an adjunctive role of GFs in modulating predictable bone growth in peri-implant areas was done. MATERIALS AND METHODS: An electronic and manual search of different databases was performed. Only randomized controlled trials (RCTs) were included and reviewed. The risk of bias (ROB) of the selected studies was assessed using the SR Centre for Laboratory Animal Experimentation (Cochrane) tool. A meta-analysis was also performed to evaluate the different study characteristics quantitatively. STATISTICAL ANALYSIS USED: The total Weighted mean difference was evaluated using the Rev-Manv5.3 algorithm. Chi-square test and I2 test were done to assess the heterogeneity between the studies. RESULTS: Seven RCTs were included in the study. These were associated with a high ROB. The total weighted mean difference (WMD) of the percentage of bone-implant contact was 3.25% (95% confidence interval [CI] = 1.49%-6.03%; P = 0.001; I2 = 91%) between groups with and without exogenous application of GFs. The total WMD of the percentage of newly formed bone area was 4.48% (95% CI = 2.31%-5.90%; P < 0.00001, I2 = 84%). A high level of heterogeneity (P < 0.001 for Chi-square test; I 2>50 %) among comparable studies was observed. CONCLUSION: The ancillary application of external GFs exhibited evidence of early osseointegration, resulting in more predictable and faster results. However, a careful discernment of conclusions drawn from this SR is a must before conducting any human trials.

Fabrication of a bicomponent hybrid orbital prosthesis.

This clinical report describes the management of the retention of an orbital prosthesis in a patient with uncontrolled diabetes. The patient, who underwent left orbital exenteration subsequent to severe mucormycosis, posed a challenge for implant placement and for use of adhesives as a method of retention because of the high likelihood of reinfection. Inaccessibility to severe anatomic undercuts along with their arbitrary block out would have caused diminished retention. As a result, an orbital prosthesis composed of a digitally produced hollow conformer and traditionally produced silicone prosthesis was provided using 3-dimensional imaging and rapid prototyping, with optimum retention.