There is currently no consensus regarding the survival rate of osseointegrated implants in patients with osteoporosis. A systematic review with meta-analysis was performed to evaluate the survival rate of implants in such patients. The PubMed/MEDLINE, Web of Science, Cochrane Library, and SciELO databases were used to identify articles published up to September 2016. The systematic review was performed in accordance with PRISMA/PICO requirements and the risk of bias was assessed (Australian National Health and Medical Research Council scale). The relative risk (RR) of implant failure and mean marginal bone loss were analyzed within a 95% confidence interval (CI). Fifteen studies involving 8859 patients and 29,798 implants were included. The main outcome of the meta-analysis indicated that there was no difference in implant survival rate between patients with and without osteoporosis, either at the implant level (RR 1.39, 95% CI 0.93-2.08; P=0.11) or at the patient level (RR 0.98, 95% CI 0.50-1.89; P=0.94). However, the meta-analysis for the secondary outcome revealed a significant difference in marginal bone loss around implants between patients with and without osteoporosis (0.18mm, 95% CI 0.05-0.30, P=0.005). Data heterogeneity was low. An increase in peri-implant bone loss was observed in the osteoporosis group. Randomized and controlled clinical studies should be conducted to analyze possible biases.

The performance of the dentine bonding systems was material dependent. CHX did not improve immediate bond strength; however, CHX negatively affected the bond strength of the self-etching system, especially in the third apical.

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Objective: To evaluate the ability of different periods of salivary exposure and two different removable appliances to rehardening initial erosive lesions. Material and Methods: This randomized, single blind in situ study was conducted with 2 crossover phases. The factors under study were: period of salivary exposure (15 minutes, 30 minutes, 1 hour and 2 hours) and type of oral appliance (maxillary or mandibular). Two hundred enamel blocks were selected by initial surface hardness (SHi). Enamel blocks were demineralized in vitro (0.05M citric acid; pH2.5 for 15 seconds), surface hardness (SHd) was remeasured and 160 blocks were selected and randomized among groups. Thus, there were 2 blocks per period of salivary exposure in each type of oral appliance for each one of the 10 volunteers. In each phase, one of the removable appliances was tested. The response variable was percentage of surface hardness recovery (%SHR=[(SHf-SHd)/SHi)]x100). Two-way ANOVA and Tukey's post hoc test were applied adopting 5% of significance. Results: No difference was found among oral appliances on enamel rehardening (p>0.01). Salivary exposure of 2 hours promoted similar enamel rehardening when compared to 1 hour (p>0.05), which showed similar rehardening to 30 min. All mentioned period of salivary exposure promoted superior rehardening than 15 min (p>0.01). Conclusion: The salivary time exposure between erosive attacks might be 2 hours to achieve a feasible maximum rehardening. In addition, both maxillary and the mandibular appliance have presented a similar rehardening ability.

Background: The aim of this study was evaluated the eroded enamel rehardening potential using upper palatal and lower buccal removable appliances in different times of salivary exposure (30 min, 1h, 2h, 12h) after a single erosive challenge event. Material and Methods: After initial surface hardness evaluation, bovine enamel blocks were eroded in vitro (0.01 M hydrochloric acid, pH 2.3, 30 seconds), selected (n = 160) and randomly assigned to the two appliance designs and twenty volunteers. Four enamel blocks were inserted in each removable appliance. On the in situ phase, the volunteers were instructed to use the upper palatal and lower buccal appliances simultaneously for 12 nonconsecutive hours. After each predetermined period of time of salivary exposure, the enamel blocks were removed from the appliances for immediate evaluation of surface hardness, enabling percentage of surface hardness recovery calculation (%SHR). The data were analyzed using two-way ANOVA and Tukey's test (α=5%). Results: The results showed no difference in the degree of enamel rehardening by the upper palatal or lower buccal appliances (p> 0.0001). Regarding the time of use of the appliances, it was demonstrated that 30 minutes (upper = 21.12%, lower = 19.84%) and 1 hour (upper = 35.69%, lower = 30.50%) promoted lower hardness recovery than two hours (upper = 44.65%, lower 40.80%) of salivary exposure (p <0.0001). The use of 12 hours (upper = 49.33%, lower = 49.00%), including the sleeping time of the volunteers did not increase the %SHR. Conclusions: The location of the appliance does not influence the re-hardening ability of saliva and the use of intraoral appliances for 2 hours seems to be appropriate for partial rehardening of the softened enamel surface.