Co-distribution of cysteine cathepsins and matrix metalloproteases in human dentin

It has been hypothesized that cysteine cathepsin's (CTs) along with matrix metalloproteases (MMPs) may work in conjunction in the proteolysis of mature dentin matrix. The aim of this study was to verify simultaneously the distribution and presence of cathepsins B (CT-B) and K (CT-K) in partially demineralized dentin; and further to evaluate the activity of CTs and MMPs in the same tissue. The distribution of CT-B and CT-K in sound human dentin was assessed by immunohistochemistry. A double-immunolabeling technique was used to identify, at once, the occurrence of those enzymes in dentin. Activities of CTs and MMPs in dentin extracts were evaluated spectrofluorometrically. In addition, in situ gelatinolytic activity of dentin was assayed by zymography. The results revealed the distribution of CT-B and CT-K along the dentin organic matrix and also indicated co-occurrence of MMPs and CTs in that tissue. The enzyme kinetics studies showed proteolytic activity in dentin extracts for both classes of proteases. Furthermore, it was observed that, at least for sound human dentin matrices, the activity of MMPs seems to be predominant over the CTs one. (C) 2016 Elsevier Ltd. All rights reserved.Peer reviewe

Direct restorative treatment of dental erosion caused by gastroesophageal reflux disease associated with bruxism: a case report

Gastroesophageal reflux disease (GERD) is a gastrointestinal disorder in which stomach acids are chronically regurgitated into the esophagus and oral cavity. Continual exposure of the teeth to these acids can cause severe tooth wear. Dentists are often the first healthcare professionals to diagnose dental erosion in patients with GERD. This article presents a case report of a 27-year-old male smoker with tooth wear and dentin sensitivity caused by GERD associated with bruxism. After diagnosis, a multidisciplinary treatment plan was established. The initial treatment approach consisted of medical follow-up with counseling on dietary and smoking habits, as well as management of the gastric disorders with medication. GERD management and the dental treatment performed for the eroded dentition are described, including diagnosis, treatment planning, and restorative therapy

Changes in the stiffness of demineralized dentin following application of tooth whitening agents

Objective. The purpose of this study was to evaluate the effect of the bleaching agents on the elastic modulus of bovine demineralized dentin matrix (EMDM). Materials and methods. Eighty-five slices were obtained from 17 bovine teeth. The slices were divided randomly into five experimental groups (n = 17): unbleached control group (CG), 4% hydrogen peroxide (HP4), 4% hydrogen peroxide + 0.05% Ca (HP4 + Ca), 7.5% hydrogen peroxide + ACP (HP7.5) and 10% carbamide peroxide (CP10). The HP4, HP4 + Ca and CP10 groups were treated with the bleaching agents for 8 h/day (14 days), while the samples of HP7.5 group were exposed to bleaching agent for 30 min twice a day (14 days). The CGwas kept in 100% humidity. After bleaching treatments, the enamel of the samples was removed and 85 dentin beams (0.5 x 1.7 x 7.0 mm) were prepared. Afterwards, the beams were immersed in 10% phosphoric acid solution (5 h) and rinsed with water (10 min). The beams were tested after 24 h, 7 and 14 days of storage in distilled water, using three-point bend method. Data were statistically analyzed using ANOVA and Fisher's test. Results. All bleaching treatments reduced the EMDM. After 14 days post-bleaching, the EMDM increased for HP4 and HP4+Ca groups. Conclusions. The use of bleaching agents promoted a decrease in EMDM, which indicates that the bleaching treatment interacts with the dentin organic matrix. The EMDM measurement for the specimens of the 7.5% hydrogen peroxide group that were immersed in water at 14 days post-bleaching did not recover the EMDM values when compared to the control group.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Effect of chemical and natural irrigant solutions on microhardness of root dentin an in vitro study

ction: Modifications in the mechanical properties of dentin may reduce the fracture resistance of tooth, especially after endodontic treatment. The aim of present study was to evaluate the effect of the irrigation with different root canal irrigants on the microhardness of root dentin. Methods: The coronal portion of 60 single-rooted bovine incisors was sectioned and the pulpal tissue removed using endodontic K-files. The roots were cut transversely to obtain 2 fragments, which were embedded in acrylic resin and randomly distributed into six groups (n=20) according to the irrigation protocol: distilled water (DW) (control); 2% chlorhexidine solution (CHX); 6% sodium hypochlorite (NaOCl); 6% calcium hypochlorite (Ca[OCl]2); QMix; and 6.5% grape seed extract solution (GSE). The solutions were kept in contact with the root dentin specimens for 30 min. After that, irrigation with 5 mL of DW was performed. The Vickers microhardness was determined by performing three indentations in all specimens, using 300-g load and 20-second dwell time. The first indentation was made 1.000 µm from the root canal entrance, and two other indentations were made at a distance of 200 µm from each other. The microhardness value for each specimen was obtained as the average of the results for the three indentations. Data were statistically analyzed using one-way ANOVA with 5% significance level. Results: All the tested irrigant solutions maintained the same microhardness level of the root dentin when compared to the control group, with no statistically significant differences between them (p<0.05) Conclusion: The tested irrigant solutions did not present ability to modify the microhardness of root dentin

Bond strength between fiber posts and root dentin treated with natural cross-linkers

He aim of this study was to investigate the effects of a proanthocyanidin-rich extract (grape seed extract [GSE]) on the bond strength and stability of the adhesion of fiber posts to the root dentine using 2 adhesive systems: a total-etch and a self-etch adhesive system. Single-rooted human teeth were randomly divided into 6 groups: G1 (control), untreated + total-etch adhesive Adper Scotchbond Multi-Purpose (3M ESPE, St Paul, MN); G2, 6.5% GSE for 5 minutes + SB; G3, 10% GSE for 5 minutes + SB; and G4 to G6 groups were similar to previous ones; however, the self-etch adhesive system Clearfil SE Bond (Kuraray, Kurashiki, Japan) was used. Fiber posts were cemented with RelyX ARC (3M ESPE), and the specimens were immediately tested for push out or stored for 12 months. The bond strength means were analyzed by analysis of variance and Games-Howell post hoc tests (alpha = 0.05). Additionally, matrix metalloproteinase inhibition by 0.65%, 0.065%, and 0.0065% GSE was examined with gelatin zymography. The use of GSE did not affect immediate bond strength to dentin and contributed to preserve the bond strength after 12 months (P < .05) for both adhesives. The bond strength of SB was significantly higher than Clearfil SE Bond (P < .05). Gelatin zymography showed reduced matrix metalloproteinase activity when recombinant enzymes were incubated with both 0.65% and 0.065% GSE, with complete inhibition at the highest concentration. The pretreatment with GSE can be used as a natural alternative to improve bond strength stability of dentin adhesive interfaces in root canals411016671671COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESBEX 17910/12-