Clinical assessment of occlusal contact variables on coronal tooth microstrain: A cross-sectional study

The influence of different occlusal contact variables on tooth strain has been less explored in the literature. The purpose of this study was to investigate the influence of different occlusal contact locations in mandibular molars on occlusal bite force, bite force distribution, and the resultant coronal microstrain.

A split-mouth, cross-sectional study was planned. Twenty-nine participants aged between 20 and 40 years with healthy dentition were studied. A 100-µm articulating paper and an iTero digital scan were used to locate occlusal contacts in mandibular molars. The control group included samples with only functional cusp contacts. The test group included samples with functional and nonfunctional cusp contacts. Upon sample categorization, the bite force at the maximum intercuspation position was evaluated in the mandibular molar region using a Tekscan B201 FlexiForce sensor for all patients. In contrast, 14 patients were evaluated by T-Scan 10 Novus to check occlusal bite force distribution. Subsequently, buccal and lingual coronal microstrain after a bite load was evaluated in all the selected mandibular molars using strain gauges.

The occlusal bite force (N) and the bite force distribution values (%) of the test group and control group were not significantly different (p = 0.96; 0.09). The lingual coronal microstrain (150.96 ± 15.84 με) in the control group was significantly lower than the buccal coronal microstrain (253.36 ±40.65 με) (p = 0.001). The test group had significantly higher lingual coronal microstrain (356.00 ± 42.43 με) than the buccal coronal microstrain (286.68 ± 44.01 με) (p = 0.001). The test group showed significantly higher lingual coronal microstrain compared to that of the control group (p = 0.001). There was no significant difference in buccal microstrain between the test and control groups (p = 0.111).

Occlusal contact characteristics displayed varying strain values, indicating that nonfunctional occlusal contacts have a significant impact on mandibular molar strain values. Excessive strain can lead to changes in the structure of the tooth, potentially resulting in the development of cracks. The present findings may improve the clinical assessment of occlusal contacts and related conditions for effective prevention of crack formation and cuspal fracture in mandibular molars.