Oral Functional Behaviors and Tooth Factors Associated with Cracked Teeth in Asymptomatic Patients

Introduction A cracked tooth may occur due to excessive applied force or tooth weakness. However, there is scant information concerning the cracked tooth risk factors. This study aimed to explore the oral functional behaviors and tooth factors associated with posterior cracked teeth. Methods Fifty-six patients underwent their oral functional behavior assessment via a questionnaire. The intraoral parameters at the patient level (remaining teeth, occluding tooth pairs, overbite, overjet, and occlusal guidance type) and tooth level (remaining marginal ridge number, restored surface number, restorative materials, and cuspal inclination) were examined. The posterior teeth were stained with methylene blue dye and inspected for cracks using a microscope. The correlations between each patient-level parameter and the cracked tooth number/subject were determined using linear regression analysis. The cracked teeth were matched with their contralateral noncracked teeth, and binary regression analysis was used to analyze the association between tooth-level parameters and a cracked tooth. Multivariate regression analysis was performed if more than 1 parameter had a P value ≤.1. Results One hundred thirty-five cracked teeth were found. Eating hard food was significantly related to the cracked tooth number (P < .05). In molars, the occlusal surface restoration and cuspal inclination were significantly related to a cracked tooth, except the mesiobuccal cusp. In the multivariate analysis, the distolingual cusp inclination significantly predicted a cracked tooth (P < .05). In premolars, the lingual cusp inclination was associated with a cracked tooth (P < .05). Conclusions Eating hard food, occlusal surface restoration, and steep cuspal inclination were associated with posterior cracked teeth.