To date, numerous materials in the dental field are marketed to ensure stable adhesive cementation of zirconia ceramics (Y-TZP). The aims of this study were to assess the shear bond strength of the new experimental cement Surgi Dual Flo’ Zr to Y-TZP compared to Panavia V5 cement, and to evaluate the effect of 10-MDP (10-methacryloyloxydecyl dihydrogen phosphate) containing primer on their bond strength. Twenty composite cylinders and Y-TZP disks were adhesively luted and divided into four groups based on cement type used and application or not of 10-MDP. The groups (n = 5 each) were S 10MDP (Surgi Dual Flo’ Zr with 10-MDP); S no 10MDP (Surgi Dual Flo’ Zr without 10-MDP); P 10MDP (Panavia V5 with 10-MDP); P no 10MDP (Panavia V5 without 10-MDP). Maximum load resistance (ML) and shear bond strength (SBS) were tested and mode of failure qualitative documented via scanning electron microscopy. The data were analyzed with one-way ANOVA, Holm-Sidak method, and Bayesian analysis. ML and SBS were significantly higher in S 10MDP than in S no 10MDP; and in P 10MDP than in P no 10MDP (p < 0.05). No significant differences were found between S 10MDP and P 10MDP; S no 10MDP and P no 10MDP (p > 0.05). Cohesive, adhesive, and mixed failure occurred among the groups. Bond strength between the experimental resin-based cement and Y-TZP was adequate for clinical application when 10-MDP was added. 10-MDP containing primer was effective improving the bond strength to Y-TZP more than the different type of resinous cement.

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The purposes of this study were to evaluate the efficacy of water–airborne-particle abrasion (WAPA) as pre-etching procedure for tooth surfaces to increase bond strength, and to compare the survival rate of WAPA vs. non-WAPA glass–ceramic restorations with a 15-year follow-up. The occlusal surfaces of 20 human molars were sectioned and flattened. The prepared surfaces areas were subdivided into two parts: one received WAPA treatment (prophy jet handpiece with 50 µm aluminium oxide particles) followed by acid etching (37% phosphoric acid for 20 s/3-step etch-and-rinse); the other one was only acid-etched. In total, 108 specimens were obtained from the teeth, of which 80 were used to measure the micro-tensile bond strength (μTBS) in the WAPA (n = 40) and control (n = 40) groups, while the remaining specimens (n = 28) were investigated via SEM to evaluate the micromorphology and roughness (Ra) before and after the different treatment steps. The survival rate (SR) was performed on 465 glass–ceramic restorations (131 patients) comparing WAPA treatment (n = 183) versus non-WAPA treatment (n = 282). The bond strength was 63.9 ± 7.7 MPa for the WAPA group and 51.7 ± 10.8 MPa for the control group (p < 0.001). The Ra was 98 ± 24 µm for the enamel control group, 150 ± 35 µm for the enamel WAPA group, 102 ± 27 µm for the dentin control group and 160 ± 25 µm for the dentin WAPA group. The Ra increase from the WAPA procedure for enamel and dentin was statistically significant (p < 0.05). Under SEM, resin tags were present in both groups although in the WAPA they appeared to be extended in a 3D arrangement. The SR of the WAPA group (11.4 years) was 94%, while the SR of the non-WAPA group (12.3 years) was 87.6% (p < 0.05). The WAPA treatment using aluminium oxide particles followed by a 3-step etch-and-rinse adhesive system significantly improved bioadhesion with an increased bond strength of 23.6% and provided superior long-term clinical performance of glass–ceramic restorations.

BackgroundThe aim of this study was the comparison of male and female upper and lower dental arch form in untreated Italian patients by 3D analysis, to find differences in shape, in transversal and longitudinal diameters between sexes, and to give a representative set of population’s dental arch to clinicians in order to provide suitable orthodontic treatment.MethodsThe sample consisted of 3D scans of dental casts deriving from 104 Italian untreated patients (Male = 35, Female = 69) in permanent dentition. An evaluation of the arch form was performed by angular and linear values on every patient using a 3D software (SolidWorks®). A Student’s two-tailed t test was used to determine if the differences in measurements between the male and female groups were significant and the level of significance was set at P < 0.05.ResultsStatistically significant differences in upper and lower transversal and longitudinal diameters were found. Male arch widths were significantly larger than those of females. Male intercanine, intermolar, and interpremolar diameters were significantly greater than females. Dental arch depth was significantly smaller in the female group. Anterior upper dental arch form was flatter, wider, and less sharp in the female group.ConclusionsBasing on the anatomical arches differences found between sexes concerning Italian patients, it is suggested to have regard to each patient pre-treatment arch form, width, and depth during orthodontic treatment according to gender.Electronic supplementary materialThe online version of this article (10.1186/s40510-018-0233-1) contains supplementary material, which is available to authorized users.

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