الفهرس 
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Abstract
Crown inclination (crown torque) is one of Andrews’ six keys to normal occlusion and the serious item for the construction of pre-adjusted appliance.1 Modification of anterior teeth torque is a main concern in orthodontics; the variety of adequate anterior teeth inclination affects many factors, such as stability, function, patient’s satisfaction, esthetics, and phonetics.2 guidelines for anterior teeth inclination correction is consequently related to esthetically and functionally satisfactory outcomes in un-treated persons with normal occlusion (NO).2 The Aim of this study: was to evaluate the crown inclination of anterior and posterior teeth on dental casts by using manual device; tooth inclination protractor TIP and advanced 3-D laser scanner, also estimating the correlation of the two methods in their measurements, and measuring the reliability for the two techniques. Materials and methods: this study was accompanied on a sample of thirty six casts of good aligned normal Class I occlusions (18 males and 18 females) of both upper and lower casts (864 teeth). The labio-lingual inclinations of anterior teeth (incisors, canines) and the bucco-lingual inclinations of posterior teeth (premolars, and first molars) was evaluated using the tooth inclination protractor ( TIP ) and the 3-D laser scanner (3Shape A/S, Copenhagen, Denmark). The dental casts were taken for volunteering subjects from the community and students of Faculty of Dentistry, Mansoura University, Egypt. Results : overall the comparison of the torque measurements between 3-D laser scanner and TIP device the readings showed that there is a statistically non-significant difference in all male study group except in upper central incisor and lower canine. While in female study group the readings obtained there is a statistically significant difference in all teeth between the two methods except upper and lower incisors. Conclusion: the correlation between the 3-D laser scanner and TIP was highly agreement for all teeth measurements. The reliability of the 3-D laser scanner was higher than TIP with ICC=0.987 and ICC=0.884 respectively. Upper and lower incisors were found to have larger positive torque; while upper and lower canines were have less negative torque.