Providing a monolithic zirconia fixed partial denture with rigid and nonrigid connectors to overcome nonparallel abutment teeth.

This clinical report describes the fabrication of a monolithic zirconia fixed partial denture using rigid and nonrigid connectors to overcome nonparallel abutment teeth. A precise key and keyway in the ceramic material was designed with digital technology, reducing material costs, improving biocompatibility, and using esthetically superior nonmetallic materials.

Design of palatal and lingual augmentation prostheses by using an intraoral scanner for a patient after a glossectomy: A clinical report.

Computer-aided design and computer-aided manufacturing was used to fabricate palatal and lingual augmentation prostheses for a patient with dysphagia after a glossectomy. The function of these prostheses was comparable with that of those fabricated by conventional methods. The patient outcome suggests that an intraoral scanner can be effectively used for the fabrication of augmentation prostheses for patients with dysphagia and a high risk of aspiration.

Fabrication of a nonmetal clasp denture supported by an intraoral scanner and CAD-CAM.

This clinical report describes the management of a patient who had a metal allergy and had difficulty sitting in a dental chair for an extended period. The presented treatment used an intraoral scanner and computer-aided design and computer-aided manufacturing (CAD-CAM) to fabricate a nonmetal clasp denture. The described procedure may reduce patient discomfort and chair-time.

Shear bond strength of ultraviolet-polymerized resin to 3D-printed denture materials: Effects of post-polymerization, surface treatments, and thermocycling.

PURPOSE: The purpose of this study is to compare the shear bond strength of ultraviolet (UV)-polymerized resin to 3D-printed denture materials, both with and without post-polymerization. Moreover, the effects of surface treatment and thermocycling on shear bond strength after post-polymerization were investigated. METHODS: Cylindrical 3D-printed denture bases and teeth specimens were prepared. The specimens are subjected to two tests. For Test 1, the specimens were bonded without any surface treatment or thermal stress for comparison with and without post-polymerization. In Test 2, specimens underwent five surface treatments: untreated (CON), ethyl acetate (EA), airborne particle abrasion (APA) with 50 µm (50-APA) and 110 µm alumina (110-APA), and tribochemical silica coating (TSC). A UV-polymerized resin was used for bonding. Half of the Test 2 specimens were thermocycled for 10,000 cycles. Shear bond strength was measured and analyzed using Kruskal-Wallis and Steel-Dwass tests (n = 8). RESULTS: In Test 1, post-polymerization significantly reduced shear bond strength of both 3D-printed denture materials (P < 0.05). No notable difference was observed between the denture teeth and the bases (P > 0.05). In Test 2, before thermocycling, the CON and EA groups exhibited low bond strengths, while the 50-APA, 110-APA, and TSC groups exhibited higher bond strengths. Thermocycling did not reduce bond strength in the latter groups, but significantly reduced bond strength in the EA group (P < 0.001). CONCLUSIONS: Post-polymerization can significantly reduce the shear bond strength of 3D-printed denture materials. Surface treatments, particularly APA and TSC, maintained bond strength even after thermocycling.

Effects of ytterbium laser surface treatment on the bonding of two resin cements to zirconia.

Monolithic zirconia crowns bonded to zirconia abutments have become more commonly used in the construction of cement-retained implant superstructures. The present study aimed to examine the effects of laser surface treatments on the bond strength of two resin cements to zirconia. Three types of surfaces were examined: untreated, alumina blasted, and ytterbium laser treated; and two types of resin cements: 4-META/MMA-TBB resin cement and composite resin cement. Half of the specimens were subjected to a thermocycling process. Subsequently, a shear bond test was carried out. In addition, surface roughness was measured for each surface type. The results showed that laser treatment increased zirconia surface roughness and that laser treatment significantly increased shear bond strength after the thermocycling of both cement types compared to no treatment. Our experimental results suggested that ytterbium laser surface treatment of zirconia increased the bond strength of resin cements.

Use of Digital Technology to Improve Objective and Reliable Assessment in Dental Student Simulation Laboratories.

The aim of this study was to assess inter-and intra-grader agreement with the use of digital scanning and a tooth preparation assessment software program in comparison to the current traditional visual grading method in a dental student simulation laboratory. Students' typodont teeth preparations from previous practical examinations were used (cast crown n=50; cast fixed partial denture abutments n=50). Five preclinical instructors received calibration training and evaluated each of the preparations by the traditional visual grading method using a rubric. The same preparations were assessed by the same instructors using a tooth preparation assessment software program (PrepCheck, Sirona). The results showed that intra-grader agreement was significantly higher when grades were determined by PrepCheck compared to the traditional visual grading method. The traditional method was associated with significantly greater inter-grader disagreement in comparison to grading using PrepCheck (p<0.05). When the average final grade for students' crown preparations by each grader was compared for the traditional method and PrepCheck, significant differences were found for all graders (p<0.001). In this study, the use of the PrepCheck software program greatly improved intra-and inter-grader agreement during grading in a student simulation laboratory. Digital technology may improve the objectivity and reliability of assessments by preclinical evaluators.

CAD/CAM-Fabricated Nonmetal Clasp Denture: In Vitro Pilot Study.

PURPOSE: The purpose of this study was to fabricate a prototype nonmetal clasp denture using computer-aided design/computer-assisted manufacture (CAD/CAM) technology. MATERIALS AND METHODS: A partially edentulous mandibular working cast was scanned using an optical scanner. A sectional denture separated by two parts was designed on the scanned cast. These parts were milled and combined, and adhered using an adhesive luting agent. RESULTS: The completed denture was delivered on the working cast and provided an excellent level of fitness. CONCLUSION: A prototype nonmetal clasp denture could be fabricated using CAD/CAM technology.