Background: The relevance of root's convergence with trauma from occlusion has not been widely studied. Anatomically, alveolar bone support can be divided into several levels. The root which is convergent gives a critical mass of alveolar bone support to the teeth so that it is inadequate to stabilize the tooth.
Aims: The purpose of the study is to observe the relevance of root's convergence with traumatic from occlusion.
Settings and design: This was an observational retrospective design.
Subjects and methods: Samples in this study consist of periapical radiograph of the maxillary and mandibular first molar teeth from the patients with periodontitis, which are aggravated with trauma from occlusion. For the root's convergence measurement, we use a line on the outer edge of the mesial, distal, occlusal, and apical planes of the tooth. To get the cutoff point of the root convergence value, receiver operating characteristic-curve test is performed.
Statistical analysis used: Spearman test results, based on the analysis of gingival recession and loss of attachment, indicating that each increase of root convergence value will be followed by a decrease of attachment.
Conclusions: Tooth which has a convergent/very convergent root contour can contribute to trauma from occlusion.
Keywords: First molar teeth; the root's convergence; trauma from occlusion.