جستجوی مقالات مرتبط با کلیدواژه « Micro leakage » در نشریات گروه « پزشکی »

Microorganisms are the main cause of pulpal and periapical diseases. The most important failure factor is the lack of proper seals for the canal, resulting in microbial leakage. Therefore, the purpose of this study was to evaluate the sealing ability of ProRoot MTA and Bio MTA in canal obturation using fluid infiltration.
In this experimental study, 46 extracted mandibular premolar single canal teeth were used. After preparing and disinfecting the teeth with 3% sodium hypochlorite, their crowns were cut off from the cement-enamel junction. The teeth were then randomly divided into four groups: Group 1 (n=20) Bio MTA, Group 2 MTA ProRoot (n=20), negative and positive control groups, each of them contained 3 teeth. The preparation of teeth was performed using the step back method. The filled teeth were then evaluated by fluid filtration for leakage prevention. Data were analyzed by Mann-Whitney test and Tukey test (α=0.05).
The results of statistical analysis showed that there was no significant difference between the MTA ProRoot and Bio MTA in sealing ability (P>0.05). That micro leakage is less in the Bio MTA group than in the ProRoot MTA group, but the difference was not significant.
This study showed that MTA ProRoot and Bio MTA can be used as appropriate canal filling materials.

One of the orthodontic treatment problems, which causes marginal gaps and microleakage between tooth and composite is microleakage of composite bonding of orthodontic brackets. The microleakage formation permitting the passage of bacteria and oral fluids, which may cause white spot lesions under the brackets surface area.This is a clinical problem during orthodontic treatment. Few studies have been conducted in this area. The aim of this study was comparison of microleakage of composite silorane base and methacrylate base composite in orthodontic brackets. Thirty human premolar were collected and divided into 2 groups. In group 1, 15 orthodontic brackets were bonded using silorane base composite, in group 2, 15 orthodontic brackets were bonded using methacrylate base composite. Then the teeth were kept in water and thermo cycled(500×, 5-55°C). Specimens were further sealed with nail varnish, stained with 5% basic fuchsin for 24 hours. Then, all teeth sectioned and dye penetration rate were examined by an esteriomicroscope, and scored 0 to 3 for marginal microleakage for the bracket- adhesive and adhesive-enamel interfaces. The data collected analyzed with SPSS16 software, and fisher exact and Mann Whitney tests. Microleakage values were lower in silorane composite than in the methacrylate group, and this difference was found to be statistically significant(P-value =0.03). Also, the rate of microleakage between adhesive-bracket than adhesive-enamel interface was meaningful(P-value=0.025). The results of the current relealed that silorane-bass silorane-base composite provided low microleakage for orthodontic brackets, for this reason, it could be used it for bonding brackets.

Back ground &

Post and core requires removal of a portion of the gutta-percha from the root canal space. When gutta- percha is removed some factors may have a negative effect on obturating material seal. the purpose of this study compare different methods of gutta percha removal immediately after obturation on apical leakage.

Samples randomly divided into 4 experimental groups (N=15) and two positive & negative control groups (n =5). In group 1 post space were prepared immediately with counter clock wise rotating GG. In group 2 post space were prepared immediately with clock wise rotating GG. In group 3post space were prepared immediately with post space bur. In group 4 post space were prepared immediately with heat carrier. Leakage was measured by using bovin serum albumin, immediately٬ 48 hours and 1 week after obturation. The mean of apical microleakage is evaluated by ANOVA & Post Hoc statistial analysis in each group & in different times.

Heat carrier group showed significantly less leakage than Other groups in all intervals (p< 0/05). Then, revers rotating GG showed less leakage and forward rotating GG showed the greatest leakage. The difference between these two groups was significant at immediate and 48 hours after obturation. Post space bur showed more leakage than reverse rotating GG but less leakage than forward rotating GG. This difference was not significant in all intervals (p>0/05).

According to this study heat carrier technique recommended for immediate post space preparation.

Micro leakage is one of the most important complications of direct tooth-colored restorations. the purpose of this investigation was to evaluate the effect of delayed placement of composite and delayed curing of two step self etch adhesive on microleakage of class V composite restorations.

72 class V cavities were prepared in buccal and lingual surfaces of 36 premolars. the specimens randomly assigned into 6 groups. adhesive was photocured in 3of the groups immediately and then composite was applied immediately, with 2min and 5min delay.in the other 3 groups, adhesive was photocured after a 30 second delay and then composite was placed immediately, with 2min and 5min delay. After thermocycling and immersion in 2% methylene blue, the teeth were sectioned and dye penetration was observed under a stereomicroscope and results were analyzed using SPSS17, kruskal wallis and mann whitney test.

kruskal wallis test showed significant difference between groups immediately, 2 and 5minutes delay placement of composite(P =0.001), no significant difference was found between groups immediately and 30 second delaye curing of adhesive(P=0.748). mann whitney test showed significant difference between groups immediately and 2minutes delay placement of composite (P=0.002),and groups immediately and 5minutes delay placement of composite (P=0.001).there was no significant difference between groups with 2 and 5minutes delay in composite placement(P=0.815).

Delayed placement of composite increased micro leakage of class V composite restorations. there was no significant difference between 2 and 5 minutes delay placement of composite.30second delayed curing of adhesive had no significant difference on micro leakage, compared to immediately curing of it.

The aim of this in vitro study was to investigate the microleakage of fissure sealant in isolated state and non isolated state. 32 extracted human premolars were stored in a saline solution at room temperature. Two grooves preparations longitudinally occlusal-gingival were prepared in buccal surface of each tooth, one of these grooves in each tooth were filled by fissure sealant, and the other groove has been contaminated with saliva after washing up acid, then filled by fissure sealant. The teeth were thermocycling between 5° C and 55° C for 2000 cycles, then the teeth were immersed in a 0.5% basic fuchsine solution for 24 h. Teeth sectioned longitudinally in a buccal-lingual direction, the sections were examined and a ranked scale was used to score dye penetration. Mann–Whitney U –test and Pearson chi-squared test were used to compare the groups for statistically significant differences at 5% significance level. Statistical analysis did not demonstrate any significant difference in the degree of microleakage of sealants in isolated state and non isolated state (P=0.35). This in vitro study demonstrated that micro leakage was evident in the test group as well as the control group, so saliva contamination for five seconds or less didn’t have any effect in sealants’ microleakage.