Caspian Journal of Dental Research

Introduction: Internal bleaching is a treatment option for wightening endodontically treated discolored teeth. Cervical resorption is one of the side effects of this method.The aim of this study was to compare the sealing ability of resin composite and light-cured resin modified glass ionomer (RMGI) as intra-orifice barriers in internal bleaching.

Materials &Methods: In this study, 34 single-canal anterior teeth were used. All samples were endodontically prepared and divided into two experimental groups (n=12) and two control groups (n=5). In the experimental groups, Gutta-percha was removed up to 3 mm below the cemento enamel junction (CEJ). RMGI and composite resin was placed over gutta-percha in the experimental groups up to the level of CEJ. After 24-hours incubation period, the bleaching agent (a mixture of sodium perborate and 30% hydrogen peroxide) was placed in the access cavities. The bleaching agents were replaced every 3 days over 9 days. Then, the access cavity was filled with 2% methylene blue for 48 hours. All samples were longitudinally sectioned and the dye penetration range was evaluated using stereomicroscope. Data was statistically analyzed by using T-student test and variance analysis.

Results: The microleakage in RMGI group was 0.945mm and in composite resin group was 0.641mm. Statistically, no significant difference was observed in microleakage between the experimental groups (p=0.121).

Conclusion: Both materials can be applied as the intra-orifice barriers for internal bleaching.

Introduction: Debridement of root canal using appropriately safe and effective irrigants is the key factor for long-term success. Purpose of this study was to compare the antibacterial effect of propolis with 5.25% sodium hypochlorite, and 2% chlorhexidine against enterococcus faecalis.

Materials &Methods: In this study, 36 single-canal roots were used. The crown was removed and instrumentation was prepared by step-back technique, then teeth were sterilized and contaminated with E. Faecalis, and divided into four groups with 9 cases: group1: Propolis, group2: 5.25% sodium hypochlorite, group3: 2% chlorhexidine and group4: controls. Irrigants were injected by a 27-gauge syringe and roots were incubated in 37°C for one week. Sampling was done and inoculated to tryptone soy broth media, after 24 hours the turbidity was measured. Samples were also cultured on agar plates, and colony-forming units were counted as CFU/ml. Data were analysed using the Mann-Whitney test.

Results: The difference between propolis with mean value of 246.77 colonies and chlorhexidine with mean value of zero colonies, was significant (P=.002). Similarly, the difference between chlorhexidine and sodium hypochlorite with mean value 203.55 of colonies was significant and they had significant difference in turbidity (P=.002), too. No significant difference was observed between propolis and sodium hypochlorite with regard to the induced colonies (P=0.781) and their turbidity (P=0.495).

Conclusion: It can be concluded that antibacterial activity of 2% chlorhexidine against E. faecalis is more obvious than propolis or 5.25% sodium hypochlorite. But antibacterial activity of propolis over 5.25% sodium hypochlorite or vice versa was not confirmed.

Introduction: Cervical root resorption is one of the most important complications of intra coronal bleaching. A way of preventing this type of resorption is using a coronal barrier under the bleaching materials. The aim of this study was to compare the sealing ability of glass ionomer cement and Pro Root Mineral Trioxide Aggregate (MTA) as a coronal barrier in intra coronal bleaching.

Materials &Methods: In this study, 40 single-root maxillary anterior teeth were endodontically prepared and divided into two experimental groups (n= 15) and two positive and negative control groups (n=5). In the experimental groups, gutta percha was removed up to 3 mm below the cemento enamel junction (CEJ).RMGI and MTA were placed over gutta percha up to the level of CEJ. After a 24-hour incubation period, the bleaching agent (a mixture of sodium perborate and 30% hydrogen peroxide) was placed in the access cavities. The bleaching agents were replaced every 3 days over 9 days. Then, the access cavity was filled with 2% methylene blue for 48 hours. All samples were longitudinally sectioned and the dye penetration range was evaluated using a stereomicroscope. Data were statistically analyzed using Kruskal-Wallis and Mann–Whitney tests (α=0.05).

Results: Leakage mean indicated that there was a significant difference between these two groups and leakage was less in ProRoot than glass ionomer.

Conclusion: It seems that the MTA can provide a better coronal seal during the bleaching.