R Shariatmadar Ahmadi
P Torkzaban
L Gholami

Statement of the problem: Early detection of periodontal disease and distruction is important for prevention of further destruction of the tissues. We carried out this study to determine the normal cement enamel junction (CEJ) to alveolar bone crest (ABC) distance in the interproximal area of primary molars on bitewing (B. W) radiographs in healthy ۷-۹ year old girls living in Hamadan, Iran. Materials and Methods: Four hundred healthy ۷-۹ year old junior school girls with no clinical evidence of dental caries, diastema and fillings in intermolar areas (D, E) were selected by cluster method and ۸۰۰ bitewing radiographs were taken and examined. Results: From ۳۲۰۰ measurements, only ۲۵۸۲ sites were included in the study. The mean cementoenemal junction- alveolar bone crest distance of all primary teeth was ۱.۱ mm. ۷.۷% of the total examined surfaces showed distances of greater than ۲mm indicating the prevalence of alveolar bone loss. The mean distances measured in the maxilla were greater than the mandible which was statistically significant (P<۰.۰۵). Conclusion: This study provides useful base line data on alveolar bone height in assessment by radiographical examination. It is important to establish proper diagnostic measurements to identify patients at risk and further studies are recommended.