Gul P, et al. J Adv Prosthodont. 2020 Jun;12(3):131-139. https://doi.org/10.4047/jap.2020.12.3.131

Objective: The aim of this study was to evaluate the trueness of 3D-printed dental inlays fabricated using different permanent dental resins and subjected to distinct postcuring times. Materials and methods: A total of 180 inlay specimens were fabricated and divided into nine groups of 20 specimens each. The inlays were first designed using 3D design software (Ansys SpaceClaim) and then transferred to a 3D printer. Using LCD technology, 60 inlays were fabricated from Senertek P-CrownV3 Ceramic (Senertek) resin, another 60 inlays from VarseoSmile Crown Plus (Bego) resin and the final 60 inlays from Saremco Print Crowntec (Crowntec) resin. Each of these three groups was divided into three equally sized subgroups (n = 20) cured with 2,000, 4,000 and 6,000 flashes, respectively, using the Otoflash G171 device (NK Optik, Germany). Then, the specimens were scanned and digitised using an intraoral digital scanner, and their trueness was evaluated by superimposing the digital measurements on the reference design and calculating their root mean squares (RMSs) and total overlap ratios (TORs). MANOVA was used to compare the measurements, and Tukey’s test was utilised for the post hoc analysis. Results: Significant differences in trueness were observed among the inlays fabricated with different resin types (p < 0.001). The Crowntec resin had the lowest RMS (0.08 ± 0.018 mm) and the highest TOR (94.59 ± 2.49%), indicating the best trueness, while Senertek had the highest RMS (0.114 ± 0.017 mm) and the lowest TOR (80.15 ± 5.95%), reflecting the lowest trueness. The postcuring time also significantly affected the trueness of the inlays. The 6,000-flashes group had the lowest RMS (0.095 ± 0.02 mm), and the 4000-flashes group had the highest TOR (89.81 ± 0.5%). The interaction between the resin type and the postcuring time was significant for the TOR (p = 0.01), suggesting that trueness improvements are material dependent. Conclusion: Both the resin type and the postcuring time significantly influenced the trueness of the 3D-printed dental inlay restorations. The Crowntec resin consistently exhibited superior trueness, and the Senertek resin demonstrated the lowest trueness. The optimal postcuring time varied by material, but 4,000 flashes generally provided favourable trueness outcomes. These findings highlight the importance of selecting an appropriate resin and optimising the postcuring parameters to enhance the trueness of dental inlays, potentially improving their clinical fit and longevity. Clinical relevance: Appropriate resin selection and adherence to optimised postcuring protocols are essential for achieving clinically true 3D-printed restorations, ultimately improving their adaptations in dental applications.

Background: This study investigated the effects of whitening mouthwashes containing active ingredients on a nanohybrid resin composite’s surface roughness (Ra) and Vickers microhardness (VHN) under distinct brushing conditions. Methods: Fifty-four disc-shaped specimens (10 mm diameter × 2 mm thickness) were fabricated and randomly assigned to three experimental conditions (n = 18): distilled water (Control), Patent Blue V-containing mouthwash (Colgate Optic White, COW), and activated charcoal-containing mouthwash (Colgate Plax White + Charcoal, CPWC). Each group was subdivided into brushed and non-brushed subgroups (n = 9). Non-brushed specimens were immersed in 20 mL of the assigned solution at 37 °C for 6 h (T1) and 12 h (T2). Brushed specimens underwent 5 000 and 10 000 brushing cycles before immersion at T1 and T2, respectively. Surface roughness was measured using a contact profilometer, and microhardness was assessed with a Vickers hardness tester. Data were analyzed using three-way mixed ANOVA, one-way ANOVA, repeated measures ANOVA, and Bonferroni correction (α = 0.05). Results: Significant differences were observed in Ra values based on mouthwash type and brushing (p < 0.05), while VHN remained unaffected (p > 0.05). In non-brushed specimens, CPWC exhibited the highest Ra increase (31.2%, + 0.296 μm), significantly higher than Control (1.6%, + 0.015 μm, p = 0.001) and COW (5.9%, + 0.055 μm, p = 0.001). Under brushed conditions, CPWC again showed the most significant increase (33.3%,+ 0.311 μm,p = 0.012). Microhardness showed no statistically significant changes across time points or groups (p > 0.05). However, at T2, CPWC (non-brushed) presented the most significant reduction (− 3.38%, − 1.4 VHN), which was significantly lower than Control (+ 1.98%, + 0.8 VHN) and COW (+ 3.3%, + 1.3 VHN) (p = 0.001). A 5.33% increase (+ 2.1 VHN, p = 0.756) was observed in the brushed CPWC group. Conclusions: Activated charcoal-containing whitening mouthwashes significantly increased surface roughness, particularly under brushing conditions, indicating a synergistic effect of chemical and mechanical wear. Microhardness values remained stable, suggesting the preservation of the internal structure. These findings highlight the need for cautious recommendation of charcoal-based mouthwashes for patients with resin restorations due to potential surface degradation risks.

The objective of this in vitro study is to examine the effect of antioxidants on the bonding strength of composite resin to bleached enamel. One hundred twenty non decay teeth were used in this study. Specimens were cut from the enamel cement junction. Then the specimens were randomly assigned into two groups-office bleaching and home bleaching. Bleaching antioxidants were applied to the first 12 subgroups. The specimens in the remaining 12 groups were kept in artificial saliva for 14 days and antioxidants were applied. Composite resin restoration was applied to all specimens. A cutting device was employed to obtain six specimens (0.9mm) from each tooth, and the microtensile bond strength (μTBS) test was performed. Data were analyzed using one-way ANOVA, the paired t-test, and Duncan’s post hoc test (p=0.05). In office bleaching specimens, immediate antioxidant application increased the μTBS values (p<0.05). Comparisons of the antioxidants individually revealed that bonding values increased after two weeks in specimens subjected to antioxidant application (p0.05). Mean μTBS values in the groups to which antioxidants were applied two weeks after home bleaching were higher than those in the groups in which antioxidants were applied immediately. The use of antioxidants after bleaching may increase the MTBS value. The clinician should take this into account especially in immediate restoration applications after bleaching.

Aim: Many pulp capping materials are commercially available, but the radiopacity levels of these materials are not clearly known. In this study, the radiopacity values of ten different pulp capping materials were evaluated by digital radiography. Material and Methods: Ten different pulp capping materials were prepared and placed in 3 mica plate moulds according to the manufacturer's instructions. In addition, a 1 mm thick molar crown section and an 11-step aluminium penetrometer were prepared for use in this study. After initial setting, the materials were kept at 37 °C in a humid environment. One specimen from each group was radiographed with an aluminium penetrometer and a 1 mm thick molar crown section. The digital radiographic images were transferred to the computer and the radiographic densities of the specimens were determined using the computer programme. After these values were converted to millimetre aluminium (mmAl), one-way ANOVA and post-hoc Tamhane tests were applied as statistical analysis. Results: Neoputty (5.19 mmAl) group showed the highest radiopacity values, while Dycal (1.23 mmAl) group showed the lowest radiopacity value (p < 0.05). While the radiopacity values of Dycal, Calcimol LC, Theracal LC, Therecal PT were lower than enamel (p < 0.05); there was no statistically significant difference with dentin (p > 0.05). Conclusion: Among the pulp capping materials tested, MTA-containing pulp capping materials showed acceptable radiopacity and may allow radiological detection during vital pulp treatment.