Effect of a cross-linking antioxidant agent on the bond strength of adhesive resin to irradiated dentin.

It has been shown that irradiation can cause structural changes in dentin that may reduce the bond strength of adhesives to dentin. Applying cross-linking or antioxidant agents may help reverse this detrimental effect and improve adhesion to dentin. This in vitro study aimed to evaluate the effects of epigallocatechin-3-gallate (EGCG) pretreatment and the time of adhesive bonding (24 hours vs 1 month) on the shear bond strength (SBS) of All-Bond Universal (ABU) to irradiated dentin using etch-and-rinse (ER) and self-etching (SE) modes. Flat dentin surfaces prepared from 96 extracted intact human molars were divided into 8 groups (n = 12) and bonded with ABU. In the control (CO) groups (CO/ER and CO/SE), bonding was performed on nonirradiated dentin; in the irradiated (IR) groups (IR/ER and IR/SE), bonding was performed on irradiated dentin; in the irradiated pretreated groups (IR/EGCG/ER and IR/EGCG/SE), irradiated dentin received a 0.1% EGCG pretreatment before bonding; and in the irradiated delayed bonding (DL) groups (IR/DL/ER and IR/DL/SE), bonding on irradiated dentin was performed 1 month after completion of radiotherapy. The irradiation protocol consisted of a total dose of 60 Gy with 2-Gy exposure applied 5 days per week for a period of 6 weeks. After bonding procedures were completed, the specimens were stored in 100% humidity at 37°C for 24 hours and then the SBS was tested in a universal testing machine. Data were analyzed using 1-way analysis of variance and Tukey tests. There was a statistically significant difference among the 8 groups (P < 0.001). Irradiation diminished the SBS in the IR/ER and IR/SE groups compared with their controls (P < 0.001). Pretreatment with EGCG significantly increased the SBS in the IR/EGCG/ER group only (P < 0.001). The difference between the IR/ER and IR/DL/ER groups was not statistically significant, and the difference between the IR/SE and IR/DL/SE groups was marginally significant (P = 0.056). Pretreatment with EGCG after acid etching restored the SBS of ABU to irradiated dentin, resulting in an adhesive performance equivalent to that observed with nonirradiated dentin. A 1-month delay between irradiation and bonding did not improve the SBS.

The public attitude towards selecting dental health centers.

STATEMENT OF THE PROBLEM: No published literature was found studying the people's reasons on why to choose or not to choose a dental care setting in south Iran, while understanding their attitude towards choosing their dental care center is consequential for planning a successful oral health care service system.    PURPOSE: To determine the factors affecting how people of the city of Shiraz choose their dental health services. MATERIALS AND METHOD: A cross-sectional analytic study was designed. A self-administered questionnaire was produced, tested and then distributed among 570 multistage randomly selected parents of schoolchildren of the city of Shiraz. Independent t-test, paired t-test and Spearman correlation were used to analyze the factors influencing participants in choosing clinics for their esthetic and non-esthetic dental treatments. RESULTS: 400 questionnaires were complete and analyzed. The recommendation from others was found to be the most encouraging factor to choose a dentist or a dental clinic. More importance was reported for various factors affecting participants' choice of dental clinic when seeking non-esthetic treatments, while recommendation and reputation of dentist/dental clinic played a vital role in esthetic treatments. The cost was more important for respondents living in more deprived districts (p= 0.05), for unemployed group (p< 0.001) and for those with less education (p< 0.001). CONCLUSION: Factors affecting people's choice for dental care proved to be highly complicated. Recommendation was found playing an important role. Dental patients consider various factors when looking for non-esthetic treatment but would go for the best possible when seeking esthetic treatments. Findings of this study indicate that patients' choice and utilization of dental service can be improved if dental clinics provide high quality of dental care with reasonable fees.