BACKGROUND: Different processing techniques are employed to obtain poly (methyl methacrylate) (PMMA) with consistent surface quality in terms of topography and tribological function. The purpose of this research is to evaluate its influence on the surface height distribution. METHODS: In this research, samples of conventional and CAD/CAM acrylic resins were prepared. The following surface roughness parameters were extracted from the profilometric readings: arithmetic mean roughness (Pa), skewness (Psk) and kurtosis (Pku). Profilometric profiles were additionally obtained. RESULTS: The average roughness (Pa) with the conventional technique was significantly higher compared to CAD/CAM (t = 4.595; P < 0.001). Heat-cured resins presented the highest mean Pa (F = 6.975; P = 0.06). Heat-cured and milled resins show lower coefficient variation (CV) values, indicating more consistent surface finishing. The surface profiles revealed distinct characteristics in terms of skewness and kurtosis. CONCLUSIONS: The surface processing method, chemical composition and resin type significantly influence the surface finishing of the resin. The CAD/CAM resins exhibited superior results in terms of surface arithmetic mean roughness (Pa). However, heat-cured resin revealed to present the better surface consistency.
Acrylic Resins , Computer-Aided Design , Materials Testing , Polymethyl Methacrylate , Surface Properties , Acrylic Resins/chemistry , Polymethyl Methacrylate/chemistry , Dental Materials/chemistry , Humans , Hot Temperature
PURPOSE: This study aimed to assess the accuracy and precision of prosthetically-driven implant placement achieved through static computer-aided implant surgery. The primary objective was to analyze the linear and angular deviations of dental implants in patients treated at a university dental clinic. Various types of surgical techniques and templates were utilized to optimize implant positioning. MATERIALS AND METHODS: A total of fiftythree dental implants were included in this study. The implants were positioned using either tooth-supported templates or tooth-tissue-supported templates with fixation pins. Two distinct guided surgery approaches were used, these being pilot drill guided and fully guided. Three-dimensional (3D) data from the implant planning phase was superimposed with the 3D data from the final implant positions using the 'Treatment Evaluation' tool within CoDiagnostix. implant planning software (Straumann AG). This enabled the automatic calculation of deviations in implant placement accuracy. RESULTS: Average angular deviation observed was 3.90 degrees. For linear deviations, the mean 3D deviation at the most coronal point of the implants was 1.04 mm, while at the implant apex it was 1.56 mm. CONCLUSION: This research demonstrates the feasibility of a digital workflow for guided implant surgery, offering a promising treatment option. Nonetheless, it is important to note that deviations do occur, with the apical region of the implant being the most affected area. Care should be taken, particularly in cases of limited bone availability.
This investigation aims to determine the effect of the same polishing protocol on the surface roughness (Ra) of different resins obtained by different processing techniques. Acrylic resins obtained by CAD/CAM technology overcame the disadvantages identified in conventional materials. A total of thirty samples (six of each resin): self-cured, heat-polymerized, injection molded, CAD/CAM 3D-printed and CAD/CAM milled were prepared. JOTA® Kit 1877 DENTUR POLISH was used to polish the samples by two techniques: manual and mechanized, with a prototype for guided polishing exclusively developed for this investigation. The Ra was measured by a profilometer. The values were analyzed using ANOVA, Games−Howell post-hoc test and One-sample t-test, with p < 0.05. Manual polishing produces lower values of Ra compared to mechanized polishing, except for injected molded resins (p = 0.713). Manual polishing reveals significant differences between the resin pairs milling/3D-printing (p = 0.012) and thermopolymerizable/milling (p = 0.024). In the mechanized technique only, significant differences regarding the Ra values were found between the self-cured/3D-printed (p = 0.004) and self-cured/thermopolymerizable pair resins (p = 0.004). Differences in surface roughness values can be attributed to the inherent characteristics of the resin and the respective processing techniques.
