Influence of Different Surface Treatments on the Bond Strength of Yttria-Stabilized Tetragonal Zirconia Ceramic.

Objective: This in vitro study evaluates the shear bond strength (SBS) of yttria-stabilized tetragonal zirconia (Y-TZP) and resin cement after different surface treatments. Materials and methods: Forty-eight ceramic cubes were divided into four groups (n = 12): G1 (control) sandblasting with Al2O3; G2-sandblasting with silica-coated Al2O3 (Rocatec); G3-Rocatec + CO2 laser; and G4-CO2 laser + Rocatec. A metallic primer was applied to the pretreated ceramic. A rubber ring was adapted on the central area, and then, the resin cement was inserted into the matrix and photoactivated. The samples were evaluated regarding surface roughness (Ra), SBS, failure type, and qualitatively with scanning electron microscopy (SEM). The data were analyzed by one-way analysis of variance followed by Tukey's test (p < 0.05). Results: The mean values of Ra (µm) were as follows: G1-4.52a, G2-4.24a,b, G3-4.10a,b, and G4-2.90b and the mean values of SBS (MPa) were as follows: G1-7.84a , G2-4.41b , G3-4.61b and G4-6.14a,b. SEM analyses showed superficial irregularities for all groups, being more prominent for G1. The presence of silica deposits was observed for G2, G3, and G4, but in the last two groups there were some linear areas, promoted by the fusion of silica, due to the thermomechanical action of the CO2 laser. Conclusions: The surface treatment with CO2 laser + Rocatec, using one MDP-based cement, can be an alternative protocol for the adhesion cementation of Y-TZP ceramic since it was as effective as the conventional pretreatment with aluminum oxide sandblasting.

Association of salivary parameters and erosive tooth wear in preschool children.

The aims of this study were to 1) assess the association between erosive tooth wear (ETW) according to the BEWE (Basic Erosive Wear Examination) scoring system and salivary parameters and 2) compare salivary parameters according to ETW severity in the subgroup of children with ETW. This cross-sectional study included 52 preschool children aged 5 years paired by sex. A calibrated examiner assessed ETW using BEWE criteria, and stimulated saliva was collected to determine salivary flow, osmolality, pH, and buffering capacity. The children were divided into two groups: without ETW (n=26; BEWE score 0) and with ETW (n=26; BEWE scores 1 and 2). Logistic regression analysis was used to determine the magnitude of the association between ETW and salivary parameters and estimates of odds ratios (OR). In the unadjusted analysis, the ETW group was more likely to have lower salivary flow (OR = 0.079; 95%CI = 0.013-0.469; p = 0.005) and lower osmolality (OR = 0.993; 95%CI = 0.985-1.000; p = 0.049). In the adjusted analysis, salivary flow remained significantly associated with ETW (OR = 0.087; 95%CI = 0.014-0.533; p = 0.008). Lower salivary osmolality values were observed in ETW, especially in preschool children with more severe ETW (BEWE score 2). Receiver operating characteristic (ROC) determined a salivary osmolality cutoff point of < 201 for the presence of ETW. In conclusion, salivary flow rate was significantly associated with ETW prevalence. Lower values of salivary osmolality were observed in preschool children with distinct erosive lesions with significant loss of tooth structure (BEWE 2).

Association of salivary parameters and erosive tooth wear in preschool children

Abstract The aims of this study were to 1) assess the association between erosive tooth wear (ETW) according to the BEWE (Basic Erosive Wear Examination) scoring system and salivary parameters and 2) compare salivary parameters according to ETW severity in the subgroup of children with ETW. This cross-sectional study included 52 preschool children aged 5 years paired by sex. A calibrated examiner assessed ETW using BEWE criteria, and stimulated saliva was collected to determine salivary flow, osmolality, pH, and buffering capacity. The children were divided into two groups: without ETW (n=26; BEWE score 0) and with ETW (n=26; BEWE scores 1 and 2). Logistic regression analysis was used to determine the magnitude of the association between ETW and salivary parameters and estimates of odds ratios (OR). In the unadjusted analysis, the ETW group was more likely to have lower salivary flow (OR = 0.079; 95%CI = 0.013-0.469; p = 0.005) and lower osmolality (OR = 0.993; 95%CI = 0.985-1.000; p = 0.049). In the adjusted analysis, salivary flow remained significantly associated with ETW (OR = 0.087; 95%CI = 0.014-0.533; p = 0.008). Lower salivary osmolality values were observed in ETW, especially in preschool children with more severe ETW (BEWE score 2). Receiver operating characteristic (ROC) determined a salivary osmolality cutoff point of < 201 for the presence of ETW. In conclusion, salivary flow rate was significantly associated with ETW prevalence. Lower values of salivary osmolality were observed in preschool children with distinct erosive lesions with significant loss of tooth structure (BEWE 2).