Objectives: This work aimed to evaluate and compare the surface roughness, contact angle, and C. albicans adhesion in three materials for removable denture bases: polymethylmethacrylate and the thermoplastic resins polypropylene and polyolefin. Methods: Nine samples were manufactured, three of each material (n=3): polypropylene, polyolefin, and polymethylmethacrylate (control group). The thermoplastic resins were fabricated by injection technique and the polymethylmethacrylate by compression technique. After laboratory polishing, the surface roughness (Ra and Rz) was assessed with the 3D optical roughness meter NPFLEX, and the contact angle was measured with the optical tensiometer Contact angle system OCA15. C. albicans adhesion was assessed through colony- forming unit assays (n=9). ANOVA and Kruskal-Wallis tests were done to compare groups, considering a significance level of 0.05. Results: All values obtained for the control group were lower than those obtained for the thermoplastic resins. Statistically significant differences were found: for Ra between polypropylene (0.15±0.072 μm) and polymethylmethacrylate (0.03±0.006 μm) (p=0.045); for the contact angle between the three groups (p<0.001) – polymethylmethacrylate (26.57±6.719°), polypropylene (57.57±11.098°), and polyolefin (69.06±8.955°); and for C. albicans adhesion between polymethylmethacrylate and polypropylene (p=0.007) and polymethylmethacrylate and polyolefin (p=0.013). Conclusions: In the tested conditions and for the materials assessed, polymethylmethacrylate showed the lowest roughness, contact angle, and C. albicans adhesion, thus exhibiting better properties for removable denture bases than the thermoplastic materials.

Implant-supported overdentures are an alternative predictable rehabilitation method that has a high impact on improving the patient's quality of life. However, some biological complications may interfere with the maintenance and survival of these overdenture implants. The goal of this article was to assess the factors that affect peri-implant success, through a hypothetical prediction model for biological complications of implant overdentures. A retrospective observational, prevalence study was conducted in 58 edentulous Caucasian patients rehabilitated with implant overdentures. A total of 229 implants were included in the study. Anamnestic, clinical, and implant-related parameters were collected and recorded in a single database. "Patient" was chosen as the unit of analysis, and a complete screening protocol was established. The data analytical study included assessing the odds ratio, concerning the presence or absence of a particular risk factor, by using binary logistic regression modeling. Probability values (p values) inferior to 0.05 were considered as representing statistically significant evidence. The performed prediction model included the following variables: mean probing depth, metal exposure, IL1B_allele2, maxillary edentulousness, and Fusobacterium nucleatum. The F. nucleatum showed significant association with the outcome. Introducing a negative coefficient appeared to prevent complications or even boost the biological defense when associated with other factors. The prediction model developed in this study could serve as a basis for further improved models that would assist clinicians in the daily diagnosis and treatment planning practice of oral rehabilitation with implant overdentures.

Background/Objectives: This study aimed to compare the cost and time implications for implant-supported prosthesis comparing three digital impression techniques: digitization with an intraoral scanner, digitization of the conventional impression (without dental casts) and digitization of the stone models. Methods: To assess the time and cost of digital impression techniques on implants, time records on intraoral scans were consulted and three models were created with one, two and six implants to assess extraoral procedures time. Costs were evaluated based on material consumption, time expenditure and operator-related expenses. Time was recorded in three stages: (1) impression-taking, (2) model fabrication and (3) overall workflow completion. Statistical analysis was performed using ANOVA to compare cost and time differences across workflows. Results: Intraoral scanning presented a reduction in chair-side time between 4 and 20% when compared to extraoral techniques. For the three clinical situations evaluated, the intraoral scanning always presented the lowest cost. The extraoral digitization of impressions showed a reduction between 51.9% and 53.6% in laboratory time and between 3.5% and 7.6% in total cost compared to stone models digitization. Conclusions: The findings of this study indicate that intraoral scanning is a more cost-effective and time-efficient alternative to traditional impression methods, providing advantages in terms of reduced material use and shorter procedural durations.

The aim of this in vitro study was to evaluate the accuracy of impressions made using two different silicones and corresponding stone casts in full-arch implant rehabilitation, using two laboratory scanners. A master model with six dental implants was created, scanned with a 12-megapixel scanner and used as digital master model. Ten implant impressions were obtained via two silicone impressions systems—Coltene^® and Zhermack^®—using the open-tray technique and poured gypsum. Two extraoral scanning systems (S600 ARTI Zirkonzhan^® and Identica T500 Medit^®) were used to scan the impressions and stone casts. Best-fit superimpositions were conducted between the master model and the virtual models obtained. A significance level of p < 0.05 was considered. The accuracy of the Medit^® scanner was 82.26 [53.18; 111.34] µm for Coltene^® silicone and 87.43 [72.00; 102.86] µm for Zhermack^® silicone, and the accuracy of the Zirkonzhan^® scanner was 69.90 [62.37; 77.43] µm for Coltene^® silicone and 80.67 [65.77; 95.57] µm for Zhermack^® silicone, without significant differences between scanners. When comparing the two silicones, no significant differences were found for the Medit^® (p = 0.112) or Zirkonzhan^® scanners (p = 0.162). The Zhermack^® scanner showed better accuracy than the corresponding stone casts in the two scanners, Medit^® (p = 0.019) and Zirkonzahn^® (p = 0.002). The extraoral digitalization of impressions in edentulous dental arches with six implants proves to be a valid technique.

This pilot study aimed to compare the fit accuracy of cobalt–chromium (Co-Cr) and polyether ether ketone (PEEK) removable partial denture frameworks, produced by digital technologies. Two study models of previously prepared Kennedy’s Class I and Class III mandibular dental arches were scanned. For each model, two frameworks were digitally designed and manufactured using a Co-Cr alloy via the selective laser melting (SLM) technique, and using PEEK via the milling technique. A qualitative assessment of the framework’s fit accuracy to the corresponding study models was carried out using calibrated endodontic instruments and image amplification. Best-fit superimpositions between the reference design and the scanned frameworks were performed using the Geomagic Control X version 2018, 3D Systems software, allowing the expression of trueness by calculating the root mean square (RMS) value. Higher fit accuracy was observed for the milled frameworks, with the Class I PEEK framework showing the best fit accuracy to the corresponding model. RMS values were Class I—148.3 μm for Co-Cr and 69.2 μm for PEEK; Class III—107.2 μm for Co-Cr and 59.7 μm for PEEK. In the experimental conditions used, the milled PEEK frameworks showed better fit accuracy and higher trueness than the SLM-printed Co-Cr ones in both Kennedy classes.