Background Accurate prediction of the mesiodistal widths of canines and premolars in children with primary dentition facilitates interception of malocclusion at an early age. Boston University (BU) approach is one, that is, based on primary teeth for predicting canine and premolar dimensions. Aim The aim was to evaluate the size of unerupted canines and premolars using BU approach in comparison to Tanaka and Johnston (T/J) analysis in a sample of Egyptian children. Materials and Methods A total of 300 children (150 boys and 150 girls) with an average age (7–10) years with existence of primary maxillary and mandibular canines and primary first molars and eruption of all permanent mandibular incisors, free from caries, restoration or any abnormalities in size, shape or structure of teeth. The mesiodistal widths of the required teeth were measured using digital caliper from which widths of permanent canines and premolars were predicted using both T/J analysis and BU approach. Results There was a strong positive correlation between BU approach and T/J analysis when used for children in mixed dentition stage. Conclusion Application of BU approach as a prediction method of permanent teeth dimension in a sample of Egyptian children from Tanta city in the mixed dentition stage revealed a strong correlation with the widely applied T/J analysis.

Introduction: Teeth eruption is a dynamic, genetically process which is a part of the odontogenesis and comprises all the tooth movement from the bone crypt until reaching the occlusal plane and starting its function. Objectives: The present study was carried out to determine the eruption dates of permanent teeth, also to study bilateral and maxillo-mandibular differences in the eruption of teeth and finally to assess sequence of permanent teeth eruption among a group of children in El Gharbia governorate. Methods: The study sample consisted of 1000 healthy Egyptian children of both sexes aged from (5-12 years) were selected from different urban and rural primary schools. They were examined by tongue depressors in the day light, mouth mirrors and light torch for recording presence or absence of teeth. Results: The first permanent tooth to erupt was the lower first molar, erupted at 7.30, 7.41 years in girls and boys respectively and the last tooth to erupt was the maxillary second molar, erupted at 11.23, 11.26 years in girls and boys respectively. Also there were no statistically significant gender differences in mean eruption ages of permanent teeth except lower canine and no significant jaw differences except incisors in both girls and boys &canines and lower second molar in girls. Finally there were insignificant differences between right and left sides in permanent dentition. Conclusion: The eruption dates of permanent teeth are delayed in EL-Gharbia governorate compared to other studies. Girls preceded boys only in lower canine.

Aims This work aimed to assess the salivary and urinary levels of nickel and chromium ions in children with stainless steel crowns and band and loop space maintainers. Settings and design The study was conducted as a clinical trial. The clinical part was carried out at Pediatric Dentistry Department, Faculty of Dentistry, Tanta University and the laboratory work was carried out at Biochemistry Department, Faculty of Medicine, Tanta University. Patients and methods Sixty children of both sexes aged between 5 and 8 years old were included in the study. The selected children were divided into two groups; group 1 included 30 children received stainless steel crowns and group 2 included 30 children received band and loop space maintainers. Salivary and urinary samples were collected from the participating children at the beginning of the study and then after 1 week, 2 weeks, 1 month, 3 months, 6 months and 9 months of receiving the appliances. The samples were prepared and analyzed for measuring nickel and chromium ions release using inductively coupled plasma optical emission spectrometry. Statistical analysis used All test statistics were performed using the SPSS software statistical package and the significance was set at P value less than or equal to 0.001. Results Salivary metal ions release reached its peak on the first week then diminished with time and urinary release increased on the first week, nearly remained stable till the first month then it decreased with time. Ions levels were higher in urine than in saliva with statistically significant differences. The release is slightly higher in group 2 but without statistically significant differences between both groups. Conclusions The maximum levels of released ions were significantly below their average dietary intake levels and did not reach their upper tolerable intake levels.