Prevalence and pattern of congenital missing teeth in a group of Iranian adolescents

Congenital missing tooth in the condition of having genetically one or more missing teeth which cannot be observed clinically or in radiographic images. This is one of the most prevalent anomalies in dental development that occurs either individually or as symptoms of a syndrome. Moreover, for permanent teeth, it is common with a reported prevalence of between 1.6-9.6%. The aim of this study was to assess the prevalence rate and the pattern of congenital missing teeth in adolescents referring to Mashhad School of Dentistry. In this cross-sectional study, a total of 600 panoramic radiographs related to the subjects aged 9-14 years [351 girls and 249 boys] were analyzed. The data were recorded in the related forms, and the analyzed using Chi-square and Exact rests. Among 600 panoramic radiographs, 94 teeth were found to be missing. The most and the least frequent missing teeth were the mandibular second premolars and the maxillary central incisors [observed in only 1 subject], respectively. The most commonly absent teeth were the mandibular second premolars, the mazillary lateral incisors, the mandibular central incisors, and the maxillary second premolars in order of the frequency. This study revealed that the frequency o missing tooth in girls to higher than that in boys. Thus, due to the girls' more aesthetic sensibility and also intricate treatment of such anomaly, accurate and frequent examination of adolescents' particularly girls' teeth for on-time diagnosis is crucial

[Evaluation of the effect of pre- and post-topical fluoride treatment on marginal microleakage of resin composite and glass ionomer restorations]

Fluoride has popularly been used as a caries prevention agent. This study evaluates the effect of fluoride gel [APF] on microleakage before and after restoration placement of tooth colored restorations. Eighty-four standard class V cavities were prepared and the specimens were randomly divided into three groups [n=14]: Group 1-APF employed before cavity preparation; Group2-APF employed after completed restoration: Group3- without APF application [control]. Buccal cavities were restored with OptiBond Solo adhesive system and Herculite XRV composite resin and lingual cavities were restored with Fuji II LC Glass ionomer. After finishing and polishing, thermal cycling followed by immersion in 0.5% basic fuchsin dye was performed. Then, the specimens were sectioned and microleakage was ranked under magnification [x40]. Two teeth of each group were treated for SEM observation. Data were subjected to statistical analysis using Kruskal Wallis and Wilcoxon tests. There were significant differences in enamel marginal microleakage of composite [14.68] and glass ionomer [16.00] restorations [p=0.02], but they similarly proceeded in dentinal margins [0.921]. The dentinal margins [2.50] of the glass ionomer in control group showed more leakage than the enamel margins [0.00] [p=0.04]. All experimental groups; either before or after fluoride therapy, showed similar microleakage in the enamel and dentinal margins. APF employed was ineffective on microleakage before and after composite resin restoration placement. Microleakage could increase in enamel margins of resin modified glass ionomer restoration with fluoride therapy protocol