[The effect of curing time and curing method on microleakge of conservative adhesive resin restorations: an in vitro study]

Using the conservative adhesive resin restoration [CAR] in uncooperative children lead to numerous problems because of being time consuming. The purpose of this study was to compare the microleakage of conservative adhesive resin restoration under separate curing and co-curing. In this experimental study, 120 intact premolar teeth were collected and 120 vertical grooves were prepared on them. Then the teeth were divided into four groups: group 1, separated curing of bonding agent, flowable composite and sealant; group 2, co-curing of all materials for 60 seconds; group 3, co-curing of all materials for 40 seconds and group 4, co-curing of all materials for 20 seconds. Then the specimens were thermocycled and immersed in basic fuchsin solution. The teeth were sectioned horizontally and dye penetration was evaluated with stereomicroscope. Date were analyzed using one-way ANOVA and Scheffe test. Mean value of dye penetration in groups 1, 2, 3, and 4 was 1.53 +/- 0.6, 2.06 +/- 0.6, 2.5 +/- 0.7 and 3.53 +/- 0.6, respectively. There was a statistically significant difference between group 1 and the other groups [P=0.0001]. Considering the problems caused by microleakage in conservative resin adhesive restorations, co-curing method should not be used. In the case of using co-curing method, 60 second curing time is suggested for sufficient polymerization

prevalence of bruxism and correlated factors in children referred to dental schools of Tehran, based on parents' report

Bruxism is defined as the habitual nonfunctional forceful contact between occlusal tooth surfaces. The aim of this study was to determine the prevalence of bruxism and correlated factors in children referred to dental schools of Tehran, based on parents' report. This cross-sectional descriptive study was conducted on 600 4-12 year-old children with a mean age of 7.4 +/- 2.4 years, who were referred to four dental schools in Tehran. After collecting information with questionnaire filled out by parents, chi[2] Fisher Test, Mann-Whitney and t-Test were used to analyze the data. The prevalence of bruxism was 26.2%. Bruxism begun in average at the age of 4.9 +/- 2 years. Also it occurred 2.6 times more in children who had a family history of bruxism [father-mother], compared to children who didn't have such a history. 87% of children with bruxism had a history of distressing events in their life, and 13% of children with bruxism did not report any history of distressing events in their life. In this study most common oral habit was nail biting. In study of parasomnias, drooling was the most, and snoring the least reported sleep disorder. Bruxism in children with drooling was twice more than in other children. The prevalence of bruxism in children with temporomandibular disorder was 63.6% and in children without TMD was 24.7%. Based on parents' report, 26.2% of children showed bruxism and there was a significant relation between bruxism and mother's job, family history, distressing event in life, parasomnias, especially drooling and sleep walking, TMD, hyperactivity, depression, acrophobia and lygophobia