The Influence of Dentine on the pH of Calcium Hydroxide, Chlorhexidine Gel, and Experimental Bioactive Glass-Based Root Canal Medicament.

OBJECTIVES: To evaluate the influence of dentine on the pH of different medications in standardized simulated canals. MATERIALS AND METHODS: Forty resin blocks were divided into groups with and without dentine powder, as follows: 2% chlorhexidine gel; 2% chlorhexidine gel associated with calcium hydroxide PA; calcium hydroxide PA delivered in propylene glycol 600; and NPG delivered in distilled water. The dentine powder was obtained from the root dentine of bovine teeth and added to the medications. The simulated canals were placed in containers with 1.5 mL of deionized water and pH was monitored in multiple intervals, up to 30 days. The mean pH values were calculated and submitted to statistical analysis using paired Student's t-test and ANOVA complemented by the Tukey test (p < 0.05). RESULTS: There was no statistical difference between the groups with and without dentine powder (p > 0.05). The pH values of calcium hydroxide were significantly higher than those of NPG in the first 24 hours (p < 0.05). After 7 days, both behaved in a similar manner. CONCLUSION: The addition of dentine powder to the medications evaluated did not alter the pH of the external solution in any of the time points tested.

Micro Push-out Bond Strength and Bioactivity Analysis of a Bioceramic Root Canal Sealer.

INTRODUCTION: Bioactive endodontic sealers have been developed to improve the quality of root canal obturation. EndoSequence Bioceramic (BC) Sealer is amongst calcium silicate-based materials recently developed for permanent root canal filling. The objective of this study was to evaluate the bioactivity of BC Sealer and its micro push-out bond strength to dentin compared to AH-Plus (AH) sealer. METHODS AND MATERIALS: To perform the micro push-out test, 24 root canals of mandibular premolars were instrumented and divided into two groups (n=12). Each root was cut into 4 slices and lumens of the canals were filled with the sealers and submitted to micro push-out test. Failure mode was assessed using scanning electron microscopy (SEM). Bioactivity of BC sealer was investigated with scanning electron microscopy/energy-dispersive X-ray (SEM/EDS) and X-ray diffraction (XRD). Bioactivity assessments were reported descriptively. Bond strength data were analyzed by parametric t-test (α=5%). RESULTS: In micro push-out test AH had higher bond strength mean values (16.29 MPa) than BC sealer (9.48 MPa) (P<0.05). Both groups had low amount of adhesive failure. SEM showed the presence of a mineral precipitate after 30 days and EDS analysis showed that those precipitates have high proportion of Ca. XRD showed peaks of crystalline phases of calcium carbonate compatible with the bioactivity. CONCLUSION: BC sealer showed indications of bioactivity and lower bond strength to dentine compared to AH.

Analyses of Budget Impact Considering the Use of the Picture Archiving and Communication System.

OBJECTIVE: To analyze the budget impact of using the picture archiving and communication system (PACS) in comparison to the screen/film system. METHODS: The budget impact analysis was conducted on the basis of registry data from the Clinics Hospital of the Faculty of Medicine, University of São Paulo, Ribeirão Preto, Brazil. The budget impacts were compared between the PACS, with high- and low-cost PACS architectures, and the screen/film system by considering reference and alternative scenarios over the course of 5 years. RESULTS: The budget impact associated with the use of PACS was lower than that associated with the use of the screen/film system in all the evaluated scenarios. The low-cost PACS architecture (mini-PACS) had an even lower budget impact, especially in the scenario in which a simulation of lower numbers of medical examinations was performed. CONCLUSIONS: The screen/film system had a high budget impact in all the scenarios evaluated, wherein its costs were higher than the available budget. In contrast, the PACS (high- and low-cost architectures) showed a budget impact that allowed for savings in resources, especially the mini-PACS. Therefore, we recommend the implementation and use of the PACS in health services with any volume of examinations performed.