Anatomical Measurement of the Vertical Length of the Root Trunk of Maxillary and Mandibular First and Second Molar Teeth in Shiraz in Year 1999

Today, the relationship between the classification of F.I.*1 and some factors such as, the amount of horizontal and vertical bone loss, the pattern of the interradicular bone and root morphology is revealed. Recently, some attention has been paid to the importance of the length of R.T.*2 in identifying the diagnosis and prognosis of F.I. So, the length of R.T. may be included in some F.I. classifications in the future. In the present study, the R.T. length of the first and second maxillary and mandibular molarteeth was measured and the prevalence of short, long and medium sized root trunks aswell as type A, B, and C was estimated.

The sample consisted of 322 first and second extractedmaxillary and mandibular molar teeth because of various reasons in Shiraz. All of theteeth were intact from C.E.J. up to the apex of the root without any fracture, filling,restoration or caries. At first, a series of reference points including C.E.J. top of thefornix on the furcation area and apex of the root were marked. The distance betweenC.E.J., and the furcation area was measured in order to determine the root trunk length,while the distance between C.E.J and the apex was measured to determine the total root length. The study was single blind and all the measurements were made by the sameoperator. Different types of R.T. were identified based on the root trunk length to thetotal root length ratio on individual aspects.

The R.T. length of buccal and mesial aspects was markedly more than that of the distal aspect in maxillary molars. Although a major proportion of RTs of all of the teeth, was included in the medium sized group, the buccal aspect of the mandibular first molars had a shorter vertical length than the others.

The results revealed that the incidence of type B, R.T. in all aspects of both maxillary and mandibular molars were more than type A and C. More incidence of F.I. on the buccal side of the mandibular first molars is related to shorter R.T. of this area than the others. Further investigations are suggested about the relationship between the amount of periodontal attachment loss and the type of the R.T.