Study of morphological characteristics of molars by X-ray

Objective To discuss the morphological characteristics of the molar crown and the root of the third molar,and to offer the theoretical basis for whether extracting or keeping the third molar.Methods Using the panoramic film to measure the crown width,crown height,root length,tooth neck width and the distance of apex of the first molar(M1),second molar(M2) and the third molar(M3),and t test among them was performed to get the differences.Results In male,there were differences among the crown width,root length,neck width of the first molar and the second molar,and the differences between the second molar and the third molar existed in the root length and the distance of apex in the maxillary; there were differences among the crown width,root length and the distance of apex the of the first molar and the second molar,and there were statistically significances between the crown height and the root length in the second molar and the third molar; but in the female,the differences existed in the crown height in the M1 and the M2,there were differences among the crown width,crown height and the root length in the M2 and M3 in maxillary.In the mandibular,the differences existed in the crown width,the root length and the distance of apex between M1 and M2,and there are differences between the root length and the distance of apex in the M2 and the M3.Conclusion In female,the differences between M2 and M3 is more remarkable than the differences between the M2 and the M3 in the maxillary.and the differences between the M1 and the M2 is more notable than the differences between the M2 and the M3; but in male,the differences between the M2 and the M3 is less remarkable than the differences between the M2 and M1.