The purpose of this study was to determine the pH values of calcium hydroxide mixtures in combination with either distilled water, two different local anaesthetic solutions or physiological saline solution, which are commonly used as a dressing materials during endodontic treatment. The pH of each vehicle prior to mix with calcium hydroxide and subsequently each prepared combination was determined using a digital pH meter. The pH measurements were determined at 3 min, 10 min, 1 h, 24 h, 48 h and 7 days. The results of this study indicated that four different water-based vehicles demonstrated similar pH changes range within pH 11-12 when mixed with calcium hydroxide.
One common negative side effect of orthodontic treatment with fixed appliances is the development of white spot lesions (WSLs) around brackets. This study is aimed at comparing the efficacy of various oral hygiene practices in preventing enamel demineralization around orthodontic brackets under similar in vitro conditions. The study included 90 extracted bovine incisors, which were randomized into six groups: fluoride toothpaste (FT), nonfluoride toothpaste (NFT), fluoride varnish plus fluoride toothpaste (FV+FT), CPP-ACP varnish plus fluoride toothpaste (CPP-ACP+FT), medical minerals gel plus nonfluoride toothpaste (MMG+NFT), and no intervention (control). All groups were subjected to demineralization and remineralization cycles. Visual appraisals were used to evaluate the changes in the enamel surface appearance at the beginning and end of the experiment. The changes in the demineralization degree were evaluated by measuring the Ca+2 concentration in the demineralization solution at different time points. The majority of teeth in the CPP-ACP+FT group exhibited no shift in appearance, whereas in the other groups, a slight change in enamel translucency was observed. At all the time points, the Ca+2 concentration in the demineralization solution in the CPP-ACP+FT group was the least among all other groups. At day 5, MMG+NFT’s preventive efficacy was significantly higher than FV+FT’s, but at days 10, 15, and 19, their efficacy was similar. However, at all the time points, MMG+NFT’s efficacy was significantly higher than that of control, whereas FV+FT’s efficacy was decreased at days 10, 15, and 19 and was close to the efficacy of control. To fight WSLs, early diagnosis was of great importance and examination of the tooth surface after air-drying for 5 s was recommended.
Objectives:The aim of this study was to investigate the influence of salivary contamination on bond strength to dentin during different application stages of 3 different adhesive systems Materials and Methods: Twenty-four caries-free human molars were sectioned horizontally with a diamond saw to expose 1 mm thick dentin disks. Totally 48 disks (two dentin disks from each tooth) were obtained and these disks were randomly divided into 3 groups according to adhesives used (Prime Bond NT, Clearfil SE Bond, Clearfil S3 Bond). Each adhesive group was further subdivided into 4 groups according to contamination methods as follows: no contamination which was the control group, contamination before adhesive application, contamination after adhesive application and contamination after polymerization of the adhesive. Transparent plastic cylindrical molds with an internal diameter of 0.7 mm and a height of 1 mm were used to place composite resin on dentin disks in order to test the microshear bond strength of the groups Three resin cylinders were attached on each dentin surface and 12 specimens were made for each group. Data were analyzed by one way ANOVA and Tukey's post hoc test. Results: Except when contamination occurred after the polymerization of two step self-etch adhesive, bond strength values of all groups showed statistically significant reduction compared with control groups (p<0.05). Conclusions: Within the limitations of this study, it can be concluded that, saliva contamination affects the bond strength to dentin of all adhesives used in this study and the type of adhesive and the stage of contamination can be effective on the bond strength of adhesive contaminated with saliva.
This method uses the same principle of transillumination as FOTI and DIFOTI. Instead of using visible light, this device uses a near-infrared (wave length: 780 to 1310nm) light to transilluminate the tooth. NIDIT is the digital system consists of a CCD sensor to capture the images, connected to a computer, special soft-
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