Morphology Characteristics And Clinical Research Of The Maxillary Second Molars

Objective: To study the morphology characteristics of tooth and root canal provided some knowledge to help the clinical work.Methods: Sixty-one teeth of seventy-two extracted maxillary second molars were collected and numbered. Then using caliper measured some morphology characteristics: the length of tooth, crown and root, the width of the crown. The number of roots and the location of apical foramen were recorded. The same sample had their crowns cut off at the level of the cemento- enamel junction, the parts of the roots were chosen as the experimental samples to observe the morphology characteristics of the developmental root fusion lines and orifices. Results: The averages of the length of the tooth, crown and root were 19.46±1.65mm, 8.19±0.77mm and 11.43±1.78mm. The averages of the width of crown were 9.57±0.99mm and 11.58±0.74mm. The tooth length had significant relation with the root length and the crown length, the same as the mesiodistal width and buccolingual width (P<0.05). The percentages of the three separate roots and fused roots were 49.18% and 47.54%. The most apical foramen located on the lateral of root canal point (62.42%). The incidences of the developmental root fusion lines with the type"Y"and"7"were 52.46% and 26.23%. There were 21.31% of the other types. The most number of orifices were the three orifices (68.85%), simultaneously having 16.39% of the four orifices.Conclusions: The anatomy of maxillary second molars was more complicated and X-ray film didn't accurately display the morphology of tooth and root canal. So it should examine carefully in order to prevent omitting root canal in clinical working.