Can universal adhesive systems bond to zirconia?

OBJECTIVE: To measure the bond strength to zirconia subjected to different surface treatments of universal bonding agents. MATERIALS AND METHODS: Eighty blocks of zirconia were obtained by CAD/CAM milling. The blocks were embedded into PVC tubes, polished sequentially with increasing granulation sandpapers and divided into two groups according to surface treatment: polished or grit-blasted with alumina particles. Each group was then subdivided by bonding agent employed: Z-Prime Plus (control); Scotchbond Universal; All Bond Universal; and Z-Prime Plus + All Bond Universal. Cylindrical composite resin build-ups were constructed atop the blocks using a two-part metal die. Specimens were stored for 24 hours and subjected to microshear bond strength testing. Statistical analyses were performed by means of the F-test (ANOVA), Student's t and Tukey's test. After sputter coating, zirconia surfaces and adhesive interfaces were analyzed by scanning electron microscopy (SEM). RESULTS: Bond strength was superior for grit-blasted zirconia. In specimens with this surface treatment, there were no significant differences between experimental groups. On SEM, blasted surfaces exhibited areas of micromechanical retention and adhesive interfaces exhibited areas of zirconia-adhesive interlocking. CONCLUSION: Universal adhesive systems were able to bond to zirconia. The interlocking promoted by grit-blasting enhanced bond strength. CLINICAL SIGNIFICANCE: Universal adhesive systems simplify bonding to zirconia and enable intraoral repair of fractures.

Canal Transportation, Centering Ability, and Dentin Removal after Instrumentation: A Micro-CT Evaluation.

AIM: The aim of this study is to evaluate and compare root canal transportation, centering ability, and amount of dentin removed after root instrumentation with different rotary and reciprocating systems, using micro-computed tomography (micro-CT). MATERIALS AND METHODS: Forty curved mesial canals of lower molars were selected and divided into four experimental groups (n = 10) according to the system used: protaper next (PTN), wave one gold (WOG), prodesign logic (LOG), and vortex blue (VTX). The roots were scanned before and after instrumentation using micro-CT, with a 16 µm isotropic resolution. RESULTS: Data were statistically analyzed using the Bioestat and the significance level was set at 0.05. For canal transportation, no significant differences were verified between the groups at 6 mm or 9 mm from the apex. At the apical third, LOG had a smaller mesial deviation when compared with PTN. A significant difference was found at the apical and coronal thirds, though with LOG having the best centering ability at the apical third and the worst one at the coronal third. All systems caused a greater wear at the coronal third (9 mm), decreasing at the apical one (3 mm), with statistically significant differences. LOG removed less dentin from the apical third (3 mm) than did the other instruments. CONCLUSION: The systems evaluated presented different results for canal transportation, centering ability, and dentin removal at each third. CLINICAL SIGNIFICANCE: The systems were evaluated together to evaluate neither the marked dental deviations nor the long-term signifiers of the databases and they were evaluated within the limits of normality. Therefore, they can be used without risks of embrittlement of the dental roots.

Treatment of an Acute Apical Abscess in a Patient With Autoimmune Hepatitis Taking Alendronate: A Case Report.

INTRODUCTION: The aim of this study was to report a patient's clinical case who was diagnosed with severe apical abscess and with autoimmune hepatitis (AIH) using immunosuppressive drugs and bisphosphonate. METHODS: A 32-year-old man of black African descent urgently sought dental surgery because of an increase in volume in the right genic region and a nuisance in the region of the lower right second premolar when chewing. After intraoral and radiographic clinical examination, the patient was diagnosed with pulp necrosis and an acute apical abscess. Because he had AIH and was taking corticosteroids and bisphosphonate (alendronate), he was submitted to endodontic therapy as a minimally invasive treatment, considering his systemic state. RESULTS: After 3 years of follow-up treatment with periapical and tomographic radiographic control, bone repair of the periapical region of the tooth was observed. CONCLUSIONS: Through this report, we can infer that it is possible to reverse the condition of a periapical lesion in a tooth with an acute apical abscess and necrotic pulp in an AIH patient who is using alendronate without the need for more invasive procedures and that would put at risk the patient's general and oral condition in the postoperative period.

Universal cements: dual activated and chemically activated.

Objective: The aim of the present study was to assess the bond strength of universal cements cured either dually or chemically only. Methods: Three cements were assessed using different types of application: dual activated (DA) or chemically activated (CA). In total 80 dentin blocks were used, obtained through the enamel wear of the lingual and buccal surfaces of bovine incisors. Standard cone-shaped cavity preparations were created using diamond burs. Subsequently, indirect restoration blocks were designed with Filtek Z350 (3M ESPE) composite resin. The teeth were divided into two groups (DA and CA) and then subdivided into four subgroups (n = 10) prior to cementation with the respective products: Duo-Link (Bisco); RelyX Ultimate (3M ESPE); Nexus 3 (Kerr) and conventional RelyX ARC (3M ESPE) as the control. The cementation in the PA group was applied following the manufacturer's instructions. The CA group was cemented in a darkroom to avoid exposure to light. They were stored in distilled water at 37 °C for 24 h and submitted to the push-out test. Data were analyzed by two-way ANOVA and Tukey's post-hoc test (p < .05). Results: The greatest bond strength results were obtained for photoactivated universal cements. Conclusion: Chemical activation is not sufficient to ensure acceptable bond strength.

Pre-treating dentin with chlorhexadine and CPP-ACP: self-etching and universal adhesive systems.

Objective: The aim of the present study was to compare the effect of pre-treating dentin with chlorhexidine, at concentrations of 0.2% and 2%, and remineralizing paste containing CPP-ACP (MI Paste - GC) on the bond strength of adhesive systems. Material and methods: In total, 80 slides of dentin were used. These slides were 2 mm thick and were obtained from bovine incisors. Standard cavities were created using diamond bur number 3131. In the control groups, a Scotchbond Universal Adhesive (SUA) self-etching adhesive system of 3M ESPE and a Clearfil SE Bond (CSE) adhesive system of Kuraray were applied, following the manufacturer's instructions. In the other groups, dentin was pretreated with chlorhexidine (0.2% and 2%) for 1 min and with MI Paste for 3 min. The cavities were restored with Z350 XT resin (3M ESPE). After 24 h of storage, the push-out test was applied at a speed of 0.5 mm/min. Results: The different dentin pretreatment techniques did not affect the intra-adhesive bond strength. There was a difference between treatment with MI Paste and chlorhexidine 0.2% in favor of the SUA, with values of 15.22 and 20.25 Mpa, respectively. Conclusions: The different pretreatment methods did not alter the immediate bond strength to dentin. Differences were only recorded when comparing the adhesives.