Dental caries is the most common chronic childhood disease. Deep caries and dental trauma are the two main etiologic factors responsible for pulp involvement. Better knowledge of the morphology of the root canals of deciduous teeth can improve the outcome of pulp treatment. In this study, 90 deciduous molar teeth (27 first mandibular molars, 27 first maxillary molars, 22 second mandibular molars and 14 second maxillary molars) were prepared using the clearing technique, and then dye was injected into the pulp cavity of each tooth. The roots of the teeth were examined under a stereomicroscope at × 10 magnification from different aspects. Measurements of root length and angulation were also recorded, and the data were analyzed using SPSS-16 software. Deciduous molar teeth in all four classes showed variability in the number of roots and root canals, and also differed in mean root length and angulation. Type I and IV root canal configurations were observed in the samples, and different types of curvature were recorded for the root canals in all four classes. As deciduous molar teeth exhibit morphologic differences from permanent teeth, a thorough knowledge of the root canals in the former can improve the outcome of pulp treatment.

Radiographs of developing teeth are commonly used to assess dental maturity. The method for assessment of dental maturity first described by Demirjian is widely used and accepted. The aim of this study was to assess the accuracy of the Demirjian method in an Iranian population in order to compare the difference in dental maturity between these children with the data obtained in Canadian children and to determine whether there is a correlation between dental maturity and BMI-for-age. In this study, the orthopantomographs of 519 healthy children (264 boys and 255 girls) aged 3.5-13.5 years were reviewed and the dental age was determined by the Demirjian method. The chronological ages of the children were obtained by subtracting their birthdates from the date of taking the radiograph. Height and weight measurements were also recorded and the data were analyzed using SPSS-16 software. The Demirjian method overestimated the age by 0.15 and 0.21 years in boys and girls, respectively. Paired t-test analysis showed that these differences were statistically significant (P = 0.001). The increase in mean age difference initiated from the underweight group towards the overweight group, but this correlation was not statistically significant (P = 0.094). Based on the amount of differences between estimated dental age and chronological age in this investigation, the Demirjian method seems to be clinically applicable in the Iranian population. (J Oral Sci 53, 37-42, 2011)

The higher mean resting salivary pH and better buffering capacity found in children without ECC are probably the contributing factors that protect against caries development; but further studies are needed to understand the effects of saliva and its characteristics and components on ECC.

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The above results suggest that HLA-DRB1*04 is associated with the susceptibility to ECC. Thus HLA-DRB1*04 detection as a molecular marker for early diagnosis of ECC may be recommended.