Journal of Dental Medicine

The root trunk (RT) of molar teeth is important diagnostic parameter that has a key roll in diagnosis and treatment planning.The purpose of this study is presenting a normal index of RT in mandibular molar teeth in different buccal (B). distal (D), Lingual (Li) and mesial (M) entrances, and to compare them with each other.It is a case series study that 351 extracted molar teeth, after removal of soft tissue and debridement of calculus, evaluated with gauge (with accuracy 0.1 mm) According to our measurement:In maxilla: M-side: 3.88± 0.15 mm, B-side: 4.7± 1.7. D- side: 4.87± 0.13mm. So with P.value <0.05 M and D RT are longer than and M RT is shorter than D RT.In mandibule: B- side: 2.73± 0.11mm and L side: 4.03±- 0.13mm. So with P.value < 0.01 Li RT is longer than B RT.According to ochsenbine classification our studying teeth have medium to long RT. We prescribe for educating the crater therapy in periodontal surgery the emphasize must be focused on craters with medium and long RT.The shortness of RT in B-side of lower molars needed the most attention during osteoctomy in resective procedures. Because RT not depended to underlying factors such as age, social and economic situation,and for large amount of sample size in our study, the result could be extended in Tehran.