Load-bearing capacity of CAD/CAM milled polymeric three-unit fixed dental prostheses: Effect of aging regimens

OBJECTIVE: This study tested the fracture load of milled and conventionally fabricated polymeric and glass-ceramic three-unit fixed dental prostheses (FDPs) after aging. MATERIALS AND METHODS: FDPs were fabricated (N = 1,050) from four computer-aided design and computer-aided manufacturing (CAD/CAM) resins: (1) AT (artBlock Temp); (2) TC (Telio CAD); (3) ZP (ZENO PMMA); (4) CT (CAD-Temp); two conventionally fabricated resins, (5) IES (integral esthetic press), (6) CMK (CronMix K), and a glass-ceramic (control) (7) PG (IMAGINE PressX). Specimens of each group were tested immediately after fabrication (n = 15 per material). Seventy-five FDPs per material type were stored in artificial saliva (37°C) and 15 of them were randomly selected after aging (1, 7, 28, 90, and 180 days) for fracture load measurement. The remaining specimens (n = 60 per material) were subjected to chewing simulation (×120.000-1.200.000, 49 N, 5°C/50°C). The data were analyzed using two-way and one-way ANOVA followed by Scheffé test. RESULTS: The interactions between FDP materials and aging time in both storage media showed a significant impact on the results (p < 0.001). Among saliva storage groups, TC and ZP showed the highest, and PG the lowest fracture load (p < 0.05). AT and CT were not affected from chewing simulation. TC, ZP, and AT presented the highest in ascending order (p < 0.05), PG and CMK showed the lowest fracture load after chewing simulation (p < 0.001). CONCLUSIONS: Aging did not influence the fracture load of FDPs made of CAD/CAM resins. FDPs made of glass-ceramic showed significantly lower fracture load than those of all resin FDPs. Clinical relevance: Considering fracture load measurements, CAD/CAM resins tested could be alternative materials to glass-ceramic for FDP construction

Patient-reported outcome measures focusing on aesthetics of implant- and tooth-supported fixed dental prostheses: A systematic review and meta-analysis.

OBJECTIVES The aim of this systematic review and meta-analysis was to summarize the existing evidence on patient-reported aesthetic outcome measures (PROMs) of implant-supported, relative to tooth-supported fixed dental prostheses. MATERIAL AND METHODS In April 2017, two reviewers independently searched the Medline (PubMed), EMBASE, and Cochrane electronic databases, focusing on studies including patient-reported aesthetic outcomes of implant- and tooth-supported fixed dental prostheses (FDPs). Human studies with a mean follow-up period of at least 1 year, a minimum of ten patients, and English, German, or French publication were included. For the comparison of subgroups, random-effects meta-regression for aggregate-level data was used. RESULTS The systematic search for implant-supported prostheses focusing on patient-reported outcomes identified 2,675 titles, which were screened by two independent authors. Fifty full-text articles were analyzed, and finally, 16 publications (including 19 relevant study cohorts) were included. For tooth-supported prostheses, no studies could be included. A total of 816 implant-supported reconstructions were analyzed by patients. Overall aesthetic evaluation by the patients' visual analogue scale (VAS) rating was high in implant-supported FDPs (median: 90.3; min-max: 80.0-94.0) and the surrounding mucosa (median: 84.7; min-max: 73.0-92.0). Individual restorative materials, implant neck design (i.e., tissue or bone level type implants), and the use of a fixed provisional had no effect on patients' ratings of the definitive implant-supported FDPs. CONCLUSIONS Aesthetics is an important patient-reported measure, which lacks in standardized methods; however, patients' satisfaction was high for implant-supported FDPs and the surrounding mucosa

Repairability of CAD/CAM high-density PMMA- and composite-based polymers

OBJECTIVE The study aimed to analyse the shear bond strength of computer-aided design and computer-aided manufacturing (CAD/CAM) polymethyl methacrylate (PMMA)- and composite-based polymer materials repaired with a conventional methacrylate-based composite after different surface pretreatments. METHODS Each 48 specimens was prepared from six different CAD/CAM polymer materials (Ambarino high-class, artBloc Temp, CAD-Temp, Lava Ultimate, Telio CAD, Everest C-Temp) and a conventional dimethacrylate-based composite (Filtek Supreme XTE, control) and aged by thermal cycling (5000 cycles, 5-55 °C). The surfaces were left untreated or were pretreated by mechanical roughening, aluminium oxide air abrasion or silica coating/silanization (each subgroup n = 12). The surfaces were further conditioned with an etch&rinse adhesive (OptiBond FL) before the repair composite (Filtek Supreme XTE) was adhered to the surface. After further thermal cycling, shear bond strength was tested, and failure modes were assessed. Shear bond strength was statistically analysed by two- and one-way ANOVAs and Weibull statistics, failure mode by chi(2) test (p ≤ 0.05). RESULTS Shear bond strength was highest for silica coating/silanization > aluminium oxide air abrasion = mechanical roughening > no surface pretreatment. Independently of the repair pretreatment, highest bond strength values were observed in the control group and for the composite-based Everest C-Temp and Ambarino high-class, while PMMA-based materials (artBloc Temp, CAD-Temp and Telio CAD) presented significantly lowest values. For all materials, repair without any surface pretreatment resulted in adhesive failures only, which mostly were reduced when surface pretreatment was performed. CONCLUSIONS Repair of CAD/CAM high-density polymers requires surface pretreatment prior to adhesive and composite application. However, four out of six of the tested CAD/CAM materials did not achieve the repair bond strength of a conventional dimethacrylate-based composite. CLINICAL RELEVANCE Repair of PMMA- and composite-based polymers can be achieved by surface pretreatment followed by application of an adhesive and a conventional methacrylate-based composite