The aim of this study was to evaluate and compare the resistance to fracture of interim restorations obtained through additive techniques (3D impressions) and subtractive techniques (milling) using a computer-aided design and manufacture (CAD/CAM) system of a three-unit fixed dental prosthesis (FDP) to ascertain its clinical importance. (1) Materials and methods: In total, 40 samples were manufactured and divided into two groups (n = 20) using: (1) light-curing micro hybrid resin for temporary crowns and bridges (PriZma 3D Bio Prov, MarketechLabs, São Paulo, Brazil) for the rapid prototyping group (RP) and (2) a polymethylmethacrylate (PMMA) CAD/CAM disc (Vipiblock Trilux, VIPI, São Paulo, Brazil) for the computer-assisted milling (CC). The resistance to fracture was determined with a universal testing machine. (2) Results: The strength and the standard deviation for the computer-assisted milling group were higher (1663.57 ± 130.25 N) than the rapid prototyping (RP) group, which had lower values of (1437.74 ± 73.41 N). (3) Conclusions: The provisional restorations from the computer-assisted milling group showed a greater resistance to fracture than the provisional restorations obtained from the rapid prototyping group.
Dental implant placement is crucial in oral rehabilitation, requiring precision for successful outcomes. Digital technologies, including surgical guides, enhance predictability and efficiency in implant procedures. However, their impact on implant positioning accuracy is still under investigation. This systematic review aimed to evaluate the literature on implant accuracy using digital prosthetically-derived surgical guides. Registered in PROSPERO (CRD 42023483194), the review employed a PICO strategy and searched PubMed for English-language, in vivo studies from 2013 to 2023 on restrictive digital prosthetically-derived surgical guides. Two reviewers independently assessed records, with a third verifying the decisions. PRISMA guidelines were followed, yielding 24 results after excluding nine duplicates. Ten studies met the criteria after title, abstract, and keyword review, with three included after verification. These studies showed coronal deviations of 0.44 mm to 0.56 mm, apical deviations of 0.64 mm to 1.03 mm, angular deviations of 2.03° to 2.42°, and vertical deviations of 0.19 mm to 0.45 mm. Superior accuracy was noted with static guided techniques, while bilateral guides offered stability and printed guides were cost-effective. A surgical guide that comes from a planning with a primary wax-up of the prosthesis leads to the placement of a dental implant that can be functionally and esthetically rehabilitated. Further research is needed to standardize outcomes and improve implant protocols and patient outcomes.
The objective of the study was to evaluate the volumetric wear of four composite materials for CAD/CAM (computer-aided design/computer-aided manufacturing) systems. The materials evaluated were: Cerasmart (CER), Shofu Block HC (SBH), Tetric CAD (TEC) and Brava (BRA). All the samples (n = 40) were subjected to simulated brushing (100,000 cycles). Wear was evaluated by superimposing pre-and post-brushing scans obtained with an intraoral optical scanner (CEREC Primescan; Dentsply Sirona, Germany), which were subsequently imported into the OraCheck software 5.0 (Dentsply Sirona, Germany). The data were analyzed by ANOVA test and Tukey’s HSD test was used for multiple comparisons. Cerasmart showed the least wear after brushing. All the tested materials exhibited mass loss.
An in vitro study evaluated the fracture resistance of four CAD/CAM restorative materials: lithium disilicate ceramic (IPS e.max CAD, EM), hybrid ceramic (Vita Enamic, VE), a polymer-based composite (Cerasmart, CS), and a novel 3D-printed resin (Ceramic Crown, CC) fabricated using digital press stereolithography (DPS) technology. Standardized full-coverage crowns were designed and manufactured for each material. All specimens underwent thermocycling and fracture testing using a universal testing machine. EM exhibited the highest fracture resistance (mean: 440.49 N), while VE showed the lowest (173.82 N). CS (265.49 N) and CC (306.76 N) presented intermediate values without statistically significant differences between them. Stereomicroscopic analysis revealed differences in fracture patterns, with IPS e.max CAD showing smooth, brittle fractures, while hybrid and polymer-based materials exhibited tortuous fracture surfaces. These results suggest that DPS technology achieves mechanical performance for Ceramic Crown comparable to that of milled polymer-based composites, while offering production advantages in terms of time efficiency. As one of the first studies to evaluate Ceramic Crown and DPS technology, these findings provide initial insights into their mechanical behavior. However, further studies are required to validate their clinical performance before widespread use can be recommended.
Background: Digital technologies, particularly CAD/CAM workflows, have transformed implant prosthodontics by improving the accuracy and efficiency of impression procedures, facilitating clinician–laboratory communication, and supporting the preservation of peri-implant tissues. Objective: To compare the three-dimensional accuracy (trueness) and passive fit of five conventional and digital impression techniques for fixed prostheses supported by two implants. Methods: An in vitro experimental study was conducted using a partially edentulous maxillary model with two implants supporting a three-unit zirconia bridge. Five impression workflows were evaluated: conventional techniques (open-tray and closed-tray, splinted and non-splinted) and digital impressions using plastic and titanium scan bodies. Three-dimensional accuracy was assessed by digital superimposition analysis, and passive fit was evaluated by marginal gap measurements using digital microscopy and ImageJ (version 1.54r) software. Statistical analyses were performed using exploratory ANOVA with Welch’s correction and Games–Howell post hoc tests (p < 0.05), complemented by effect size analysis. Results: Three-dimensional superimposition analysis revealed that digital impression workflows and the splinted conventional open-tray technique exhibited the highest trueness, with minimal spatial deviations relative to the reference model, together with the lowest marginal gap values (<1 µm). The non-splinted open-tray technique presented higher discrepancies (7.37 ± 0.94 µm), although all techniques remained within clinically acceptable tolerance ranges (60–150 µm). Conclusions: Under controlled in vitro conditions, both digital impression techniques and conventional splinted protocols achieve high three-dimensional accuracy and clinically acceptable passive fit for multi-implant-supported fixed prostheses. Digital workflows represent a predictable and efficient alternative, while conventional splinted impressions remain a reliable option depending on clinical and technological considerations.
To evaluate the effect of copper and zinc oxide nanoparticles (CuZnONps) added into a universal adhesive on the antimicrobial and bonding properties under a cariogenic challenge (CC). An experimental adhesive containing 0.2% CuNps and 5% ZnONps (0.2/5% CuZnNps), and a control (0% CuZnONps) were applied to enamel-free molars (n = 56), distributed into four groups (n = 14) based on adhesive strategy (etch and rinse [ER] and self-etch [SE]). Restored molars were sectioned into specimens and allocated to immediate evaluation (IM) or to a 42-day in situ (CC) [14 volunteers]. Antimicrobial properties were assessed by CFU counts, SEM, bacterial viability, and mineral loss (ML). Bonding properties were evaluated by microtensile bond strength (µTBS), nanoleakage (NL) and degree of conversion (DC). Data were analyzed using ANOVA and Tukey's post-hoc test (α = 0.05). CuZnONps significantly reduced CFU counts for mutans streptococci (p < 0.003) and total fungi (p < 0.03). SEM showed biofilm with complex morphology. Bacterial viability and ML significantly decrease in CuZnONps groups (p < 0.001; p < 0.0002). After CC, μTBS significantly decreased in ER groups (p < 0.002), while SE CuZnONps showed no significant difference between IM and CC (p > 0.35). Control NL significantly increased after CC (p < 0.001). DC values were unaffected (p = 0.29). Under a cariogenic challenge, a universal adhesive containing CuZnONps demonstrated localized antimicrobial activity and reduced dentin mineral loss and nanoleakage. Importantly, the incorporation of these nanoparticles did not compromise bond strength or the degree of conversion.