Computer-aided design and computer-aided manufacturer indirect versus direct composite restorations: A randomized clinical trial.

OBJECTIVE: This study compared the clinical performance of large indirect restorations (IRs) versus direct restorations (DRs) in posterior teeth. METHODS: Thirty subjects received two class II restorations (n = 60), one fabricated from a precured composite block (Grandio Blocs, VOCO) for the indirect technique (IT) and the other with light-cured composite (GrandioSO, VOCO) for the direct technique (DT). For IT, the restoration was created using the computer-aided design and computer-aided manufacturer (CAD/CAM) system. For DT, the material was applied light-cured by using a layering technique. All restorations were evaluated by using the World Dental Federation criteria. RESULTS: Twenty-three subjects attended the 2-year recall, and 46 restorations were evaluated. No significant differences were detected between the techniques for most parameters analyzed (p > 0.05). For "color match" at 7 days and 6 months, better results were observed for the DT. In relation to the overall scores, all restorations were esthetically acceptable after 2 years, while 93.3% of DT and 90% of IT showed acceptable function. For biological scores, 96.67% of DRs and 100% of IRs was acceptable after 24 months. Considering all properties, the success rates were 93.3% for DRs and 90% for IRs. CONCLUSIONS: After 2 years, both restorations presented similar and good clinical behavior for all the properties analyzed. CLINICAL SIGNIFICANCE: Light-cured direct posterior composite restorations may perform similarly to indirect composite restorations made with precured CAD/CAM composite blocks up to 2 years.

Color masking prediction of posterior white spot lesions by resin infiltration in vitro.

OBJECTIVE: To investigate parameters that could predict the color masking effect (ME) of white spot lesions (WSLs) after resin infiltration (RI). METHODS: Sixty extracted human teeth with natural WSLs were selected (28 premolars, 29 molars and 3 incisors). At baseline, the laser fluorescence (LF) of surrounding sound enamel (SE) and the WSLs were analyzed with DIAGNOdent. Standardized photographs were obtained under D65 and UV illuminants, from which the CIE L*a*b* color coordinates and natural fluorescence (NF) of the WSLs and SE were obtained. The color difference (ΔE00) and differences of NF and LF between the SE and WSLs were calculated. The lesion dimensions (area, perimeter, width, and height) were determined. After RI, the assessments were repeated. ME was considered as the reduction of ΔE00 values after RI. One-way ANOVA and the Tukey tests were used to analyze the absolute means of the LF and NF values. The t test was used to compare the ΔE00 values and lesion dimensions before and after infiltration. The correlations between all parameters at baseline and ME were analyzed. RESULTS: The absolute mean values of LF at the baseline (B) and after infiltration (I) were SE/B-3.98a, WSL/B-13.28c, SE/I-3.36a, WSL/I-7.95b (p = 0.001). The mean values for NF were SE/B-7.93a; WSL/B-6.29b, SE/I-7.93a, WSL/I-7.27a (p = 0.001). The results for ΔE00 were B-11.74a, I-8.66b (p = 0.001). RI significantly reduced lesion dimensions. No correlations were observed between the baseline parameters and the ME. CONCLUSIONS: The WSLs presented higher LF and smaller NF than SE, which were respectively reduced and increased after RI. Prediction of the masking effect by the parameters evaluated at baseline was not possible, which could be due to the choice of mainly caries lesions in posterior teeth. Nonetheless, infiltration was found suitable to mask most of the WSL. CLINICAL SIGNIFICANCE: The color masking effect of white spot lesions after resin infiltration cannot be predicted by a previous analysis of fluorescence, color, or dimensions of the lesion.

Influence of desensitizing and anti-erosive toothpastes on dentine permeability: An in vitro study.

OBJECTIVE: This study analyzed the effect of desensitizing and/or anti-erosive toothpastes on dentine permeability. METHODS: One-mm dentin discs were prepared from human molars and exposed to EDTA solution (5 min, 17%). Initial dentine permeability was measured, under constant pressure. Specimens were randomly allocated into 10 groups: four anti-erosive toothpastes (calcium silicate + sodium phosphate, potassium nitrate, stannous chloride + chitosan, oligopeptide-104); four desensitizing toothpastes (arginine + calcium carbonate, calcium sodium phosphosilicate, strontium acetate, stannous fluoride); and two controls (regular fluoridated toothpaste, and human saliva). They were submitted to a 5-day erosion-abrasion cycling model. Erosion consisted of immersion in citric acid (2 min, 0.3%, natural pH ˜ 2.6, 4x/day), followed by 1 h exposure to human saliva. Specimens were brushed for 15 s (2 N, 45 strokes) with the toothpaste slurries (total exposure time of 2 min). After 5 cycles, the final dentine permeability was determined. Dentine permeability change was calculated as a percentage of the initial hydraulic conductance (%Lp). Data were analyzed with one-way ANOVA and Tukey tests (α=0.05). RESULTS: The toothpastes calcium silicate + sodium phosphate and potassium nitrate, showed significant decrease in %Lp, with no difference between them. The regular fluoridated toothpaste also decreased the %Lp, not differing from potassium nitrate. No desensitizing toothpaste showed change in %Lp. Human saliva, oligopeptide-104 and stannous chloride + chitosan presented significant increase in %Lp, without difference between them. CONCLUSION: Calcium silicate + sodium phosphate, potassium nitrate, and the regular fluoridated toothpaste decreased dentine permeability, whereas the desensitizing toothpastes tested did not. CLINICAL RELEVANCE: Toothpastes had distinct impacts on dentine permeability, which may reflect a variable effect on the treatment of dentine hypersensitivity. Within the limitations of a laboratory-based study, toothpastes with an anti-erosive claim could also be effective in reducing the pain in dentine hypersensitivity.

Influence of application methods of self-etching adhesive systems on adhesive bond strength to dentin.

PURPOSE: To assess the influence of variations in the application technique of self-etching adhesive systems on the shear bond strength to dentin. MATERIALS AND METHODS: The buccal surface of 255 extracted bovine teeth was ground to expose a flat dentin surface; the teeth were divided into four experimental groups. The self-etching adhesive systems One Up Bond F Plus, Clearfil SE Bond, Xeno III, and FuturaBond NR were used, and the etch-and-rinse adhesive Adper Single Bond 2 was used as the control group. One or two layers of the self-etching systems were actively or passively applied. Cylinders of composite resin were bonded to dentin, and after 24 h, specimens were shear tested in a universal testing machine at a crosshead speed of 1 mm/min. The data were submitted to two-way ANOVA, Dunnett's and Tukey's test (5%). RESULTS: There were significant differences for the factors adhesive type, application method, and their interaction. All adhesive systems showed significant differences. The active application of two layers of self-etching bonding systems resulted in a significantly higher mean than the passive application method. CONCLUSION: The active application of self-etching adhesive systems tends to increase the dentin shear bond strength, and the influence of the application method depends on the tested adhesive.