Evaluation of Coronal Microstrain and Bite Force in Patients with Tooth Wear – An In Vivo Study

AIM: This clinical study investigated coronal microstrain values in mandibular first molars of patients with tooth wear. MATERIALS AND METHODS: Thirty patients (40-60 years) with and without occlusal tooth wear in mandibular first molars were selected and categorised into three groups (n = 10 each). Group 1 was the control group with Tooth Wear Index 0 (TWI: 0); Group 2 had TWI grade 1-2; and Group 3 had TWI grade 3. Initially, the maximum physiologic bite force in the first molar regions were determined using Flexiforce sensors, followed by the occlusal contact area. Next, the buccal and lingual microstrain values of mandibular first molars were recorded after a physiologic bite load. Additionally, all parameters were recorded for Group 3 after composite restoration and adjustments of non-functional occlusal contacts. Data were analysed using the Kruskal-Wallis test with Bonferroni correction (P < 0.05). RESULTS: Mean bite force values were similar between groups (P = 1.000). Mean buccal and lingual microstrain values in Group 3 were significantly higher than those of controls (P = 0.003, 0.021). Mean lingual microstrain values of Group 3 were significantly higher than those of Group 2 (P = 0.009). Restoration of molars in Group 3 resulted in reduced mean microstrain values that were similar to those of the controls (P = 0.190). CONCLUSION: Coronal microstrain values of mandibular molars increased with severe tooth wear but reduced after placement of composite restorations and elimination of non-functional contacts. Severe occlusal wear increases coronal strain, and placement of a bonded restoration and occlusal correction can limit further wear and fracture.