Prediction of the size of unerupted canines and premolars in an Iranian population.

Background and Aim: One of the important aspects of diagnosis and treatment planning in the mixed dentition is estimation of the size of unerupted permanent canines and premolars. One of the most commonly used the prediction methods are Tanaka and Johnston, which are based on data from a sample of Northern European descent children. The accuracy of this method when applied to a different ethnic population is questionable. The aim of this study was to determine the modified equations from Tanaka and Johnston for Iranian population. Materials and Methods: This study was an analytic and cross-sectional investigation with the randomized cluster sampling in Ahwaz. Fifty four students of 14-18 years age (32 girls, 22 boys) were selected between 320 students and plaster models of their maxillary and mandibular arches were prepared. Subjects had fully erupted teeth, class I canine and molar relationship and presented no proximal caries or fillings, morphological anomalies, missing teeth or occlusal abrasion, and bruxism. The mesiodistal crown diameters of the permanent teeth were measured with using the sharpened boley gauge (accuracy 0.01 mm). The data were analyzed by using the regression correlation analyses and t-test. Results: The size of permanent canines and premolars were larger in maxilla than mandible and males than females. These values in Iran were different from other countries. Conclusion: In this study to predict the space (in mm) required for alignment of unerupted canine and premolars in Iranian children, halve the sum of mesiodistal dimension of the four mandibular incisors and add the respective constants 10.5 for upper jaw and 10 for lower jaw.

An in vitro comparison of microleakage of two self-etched adhesive and the one-bottle adhesive used in pit and fissure sealant with or without saliva contamination.

Aims and Objectives: To minimize the deleterious effects of contaminated enamel on bonding, some authors have advocated the use of adhesive systems under the sealant. The aim of this study was to compare the microleakage of two self-etch and the one-bottle adhesive used in pit and fissure sealant with or without saliva contamination. Materials and Methods: Sixty extracted premolar teeth were assigned to the six groups. Group 1: Acid +saliva +single bond +sealant, Group 2: Acid +single bond +sealant, Group 3: Saliva +S 3 bond +sealant, Group 4: S 3 bond +sealant, Group 5: Saliva +protect bond +sealant, Group 6: Protect bond +sealant. The teeth were thermocycled and immersed in 2% basic fuchsine dye for 24 h, then sectioned and examined with a stereomicroscope under ×40 magnification. The results were evaluated with Kruskal-Wallis and Dunn tests. Results: Group 2 has the lower microleakage scores than Groups 4 and 6. Also, Group 6 has the lower microleakage scores than Group 4, and generally an increase in microleakage was observed in each group related to contamination. Conclusion: The best technique of sealant therapy in saliva contaminated and non- contaminated condition is the use of acid-etching and bonding agent.