RESUMEN

PURPOSE: To evaluate the effect of 6 irrigant regimens on the microshear bond strength of different adhesives to pulp chamber dentin and to determine their interfacial morphology by SEM. MATERIALS AND METHODS: Forty-three human molars were split into halves and ground to provide flat pulp chamber dentin. Eighty-five halves were used. The specimens were assigned to 6 groups according to the irrigant regimen used. Group I (n=10) was irrigated with distilled water (control). The remaining 5 groups (n=15 each) were irrigated with 5.25% NaOCl followed by either 5.25% NaOCl, 17% EDTA, benzalkonium chloride (Tubilcid Plus) or MTAD (Biopure), either rinsed or not. Irrigated specimens were bonded using Clearfil S3 Bond or Adper Single Bond 2, which was employed with or without etching. Resin composite cylinders were bonded using tygon tubes for microshear bond strength testing. Data were analyzed using two-way ANOVA followed by Tukey's post-hoc test. Representative specimens of each group were prepared from 17 further molars for interfacial SEM examination. RESULTS: The different irrigant regimens used did not significantly alter the microshear bond strength values using either of the bonding systems, except NaOCl, which significantly reduced the microshear bond strength values with Adper Single Bond 2. Bonding irrigated specimens directly using the Adper Single Bond 2 without prior etching provided significantly reduced values. CONCLUSION: The irrigant regimens examined could be used safely prior to bonding except for the NaOCl, which should be negated if it is to be followed by Adper Single Bond 2, and the etching step cannot be omitted if an etch-and-rinse adhesive system is the adhesive of choice.

Asunto(s)

RESUMEN

UNLABELLED: This study was conducted to evaluate different regimens of 0.12% chlohexidine (CHX) rinse on the salivary parameters and Mutans Streptococci (MS) for a group of Egyptians. Twenty one females were recruited based on inclusive exclusive criteria. They were assigned to three different groups according to the CHX regimen specified. Salivary parameters (unstimulated salivary flow rate, stimulated salivary flow rate, pH and buffering capacity) and salivary mutans streptococci were evaluated at base line for all participants. Diet recording was done for 4 days in a supplied chart. DMFS and DS scores were also determined. This was followed by the use of 0.12% CHX mouth rinse once daily for 60 seconds before bedtime for either 3,7 or 14 days. Salivary parameters were re-evaluated in the early morning after the use of the mouth rinse, after 1 month and 3months. Mutans Streptococci (MS) were also evaluated at the same intervals. The salivary parameters did not show any difference throughout the study. The majority of the participants belonged to the moderate low fermentable CHO diet content category and they consumed five meals of cariogenic intake per day. Their DMFS scores ranged between 2 and 50 whereas the DS scores ranged between 2 and 10. The 3 day regimen was not statistically significantly different from the 7 and 14 days regimens and the maximum efficacy of CHX was obtained immediately after its use and lasted throughout the first week after stopping it. The effect of the CHX disappeared after 1 month and gradually reached the base line and surpassed this level sometimes. CONCLUSION AND RECOMMENDATIONS: A regimen of once daily use of 15 ml of 0.12% CHX mouth rinse for 3 days is effective in reducing MS below critical values. It is recommended to reuse the CHX rinse after 1 month owing to the cessation of its effect. Patients who start using CHX should not discontinue it.