CBCT Study Of Proximal Enamel Thickness Of Permanent Teeth

Introduction: Interproximal reduction(IPR)can solve many common clinical problems of orthodontic treatment.Athough the amount of enamel removed is closely related to the thickness of proximal enamel thickness,few literatures have reported that.To measure the distal and mesial interproximal enamel thickness of permanent tooth by the cone beam computerized tomography(CBCT)and clinical guidance.Methods:856 teeth were selected from 30 patients between 18 and 30 years old by CBCT and Three-dimensional measurement software In Vivo Dental was applied to respectively measure the distal and mesial proximal enamel thickness and statistical analysis was performed.Results: The distal proximal enamel thickness is greater than The mesial proximal enamel thickness.There was no significant difference in the distal and mesial enamel thickness of central incisor,lateral incisor,canine,first premolar,second premolar and first molar,however,the mesial enamel thickness of maxillary or mandibular second molars was significantly different from the distal enamel thickness of second molars(P<0.05).The enamel thickness of maxillary lateral incisor is the thinnest in the proximal distal and mesial enamel thickness of the upper dentition,which is 0.79±0.26 mm.The enamel thickness of mandibular central incisor and lateral incisor was the thinnest in the lower dentition.The enamel thickness of lower central incisor was 0.55±0.14 mm,and that of lateral incisor was 0.61±0.16 mm.There was significant difference in total enamel thickness between maxilla and mandible(P<0.01),The total enamel thickness of maxilla was 1.05 +0.30 mm,and that of mandible was 0.94 +0.34 mm.Comparing the difference of mesial and distal enamel thickness between male and female,There was gender difference in the thickness of the mesial enamel of the maxillary second premolar and the mandibular canine,as well as the thickness of the distal enamel the maxillary first premolar,maxillary second molar and the mandibular incisor had gender difference.The enamel thickness of female was greater than that of male and it is statistically significant(P<0.05).The average enamel thickness of each tooth was compared between male and female.The male enamel thickness of the mandibular canine was 0.90±0.21 mm,and the female enamel thickness was 0.81±0.29 mm.The enamel thickness of the maxillary first premolar,the maxillary second premolar,the mandibular central incisor,and the mandibular second molar was gender difference(P<0.05),which female enamel thickness was greater than that of the male.There are no gender differences in the remaining tooth enamel thickness.There was no statistical difference in gender between the proximal and distal enamel thickness of the mandible(P>0.05).In terms of numerical values,the thickness of the mandibular enamel was still greater than that of the male.Conclusions: The enamel thickness of different teeth is different,and the enamel thickness of the incisor area is the smallest relative to the enamel thickness of the whole dentition.The enamel thickness of the mandibular incisor and the maxillary incisor should be paid attention when performing interproximal reduction.0.5 mm of the proximal area of two adjacent teeth is usually used to remove enamel clinically.0.25 mm has accounted for 50% of the thickness of the enamel of the lower incisor.Lower incisors should be reduced amount of IPR.It is suggested that the amount of removal enamel thickness in the proximal area of lower anterior teeth should be 0.4 mm.It is safe to remove 0.5mm enamel thickness from the proximal areas of the upper teeth and lower posterior teeth,and even could increase amount of IPR appropriately.The maximum space of the upper dentition was 10.2 mm by IPR,and that of the lower dentition was 9 mm.There are many factors affecting enamel thickness and large individual differences.CBCT should be taken before designing a large number of interproximal reduction,and the scheme should be set according to the actual enamel thickness.