Clinical efficacy of nano-hydroxyapatite in dentin hypersensitivity: A systematic review and meta-analysis.

OBJECTIVES: To evaluate the desensitizing effect of nano-hydroxyapatite (n-HAP) on dentine hypersensitivity (DH). SOURCES: Seven electronic databases were searched on April 27, 2018. STUDY SELECTION: Randomized clinical trials (RCTs) were included based on the PICO strategy: Participants - Humans with DH; Intervention - n-HAP-containing desensitizing; Comparison -n-HAP-free treatments or placebo/negative control; and Outcomes - relief of DH. The risk of bias was classified by the Cochrane guidelines. Five meta-analyses were performed to evaluate the efficacy of n-HAP with regard to pain assessment stimuli (primary outcome); comparison of n-HAP with other treatments or placebo/negative control, and effectiveness of at-home and in-office n-HAP use (secondary outcomes). The quality of the evidence was evaluated using the GRADE. DATA: Six RCTs with 4 weeks of follow-up were included in the meta-analysis. For the primary outcome, n-HAP showed a better desensitizing effect for evaporative stimuli (SMD -1.09 [-1.24, -0.94], p < 0.00001) and tactile stimuli (SMD -0.93 [-1.42, -0.43]) than other treatments (p = 0.0002). However, there was no difference between n-HAP and other treatments for the cold stimuli (SMD -0.17 [-0.81, 0.48], p = 0.61). In an overall analysis, n-HAP-containing treatment showing the most significant desensitizing effect (SMD -0.93 [-1.19, -0.68], p < 0.00001) with a high quality of evidence for pooled results. In the secondary outcomes, n-HAP showed the best effect in the overall analysis (p < 0.05) with moderate quality evidence. CONCLUSIONS: The n-HAP-containing treatment showed better clinical performance than other treatments for DH relief. However, long-term follow-up RCTs are required in the future before definitive recommendations can be made. CLINICAL SIGNIFICANCE: Dentin hypersensitivity is a common global condition and its multifactorial etiology has led to the development of several treatments. The n-HAP-containing treatment showed greater DH relief when compared to other desensitizing agents, placebo or negative control.

A clinical, randomized, double-blind study on the use of toothpastes immediately after at-home tooth bleaching.

PURPOSE: To evaluate the effect of 5% potassium nitrate containing 2% sodium fluoride and 10% strontium chloride on tooth sensitivity and color change after at-home bleaching treatment across 3 months of follow-up. METHODS: 60 subjects were randomly allocated by numerical draw into three groups (n= 20): (1) Control, treated with 22% carbamide peroxide (CP) followed by application of a toothpaste without active ingredient: (2) Nitrate, treated with 22% CP followed by application of a toothpaste containing 5% potassium nitrate and 2% sodium fluoride: (3) Strontium, treated with 22% CP followed by application of a toothpaste containing 10% strontium chloride. An air jet was used to evaluate post-bleaching sensitivity associated with a modified visual analogue scale (VAS). A spectrophotometer was used to measure the color of the maxillary incisors. RESULTS: The Friedman vs Kruskal-Wallis tests showed that the tooth sensitivity associated with the experimental groups during 10 days of bleaching treatment was lower than that reported with the Control (P= 0.043). ANOVA showed that variation in ΔE revealed no significant difference in tooth color among the groups for the different evaluation times (P= 0.923). CLINICAL SIGNIFICANCE: The use of a toothpaste containing 5% potassium nitrate associated with 22% carbamide peroxide improves symptoms of dentin sensitivity after 10 days of bleaching treatment.

Chemical Composition and Microhardness of Human Enamel Treated with Fluoridated Whintening Agents. A Study in Situ.

BACKGROUND: Dental whitening has been increasingly sought out to improve dental aesthetics, but may cause chemical and morphological changes in dental enamel surfaces. OBJECTIVE: Assess in situ the effects of high-concentration hydrogen peroxide with and without fluoride on human dental enamel using the ion chromatography test (IC) and the Knoop hardness test (KHN). MATERIAL AND METHODS: Nineteen enamel specimens were prepared using third human molars. These specimens were fixed on molars of volunteers and were divided into groups: OP38-Opalescence Boost PF38%, PO37-Pola Office 37.5% and CO-Control group. For chemical analysis (n= 3), the dentin layer was removed, keeping only the enamel, which was subjected to acidic digestion by microwave radiation. It was necessary to perform sample dilutions for the elements fluorine (F), calcium (Ca) and phosphorus (P) for quantification using the IC test. The KHN (n= 5) was performed before and after the treatments. Five indentations were made, separated by 100 µm, for each specimen using a load of 25 gf for 5 seconds in the microdurometer. The data were analyzed using ANOVA with a 5% significance level. RESULTS: The OP38 group had the largest concentrations of F, Ca and P ions. The PO37 group showed the lowest concentrations of F and Ca ions. The average KHN was not significantly different between the OP38 and PO37 groups. CONCLUSION: Enamel whitened with hydrogen peroxide containing fluoride had greater concentrations of F, Ca and P ions. The presence of fluoride in the whitening agent did not influence the enamel microhardness.