Congenital Morphology and Occlusion in Cracked Teeth: A Combined T-Scan and Finite Element Analysis.

INTRODUCTION: To investigate the biomechanical characteristics of innate occlusal contact patterns in cracked teeth (CT) using T-Scan analysis combined with finite element analysis (FEA), and to establish a theoretical foundation for clinical prevention and restorative strategies. METHODS: Twelve patients with cracked maxillary first molars (MFMs) exhibiting mesial marginal ridge cracks and twelve controls were enrolled. Occlusal contacts were recorded using T-Scan, with categorical variables analyzed via Fisher's exact test (p < 0.05). Patient-specific finite element models were constructed from CBCT data of three cracked and three intact MFMs. Stress distribution under different loadings was compared using two-way ANOVA (p < 0.05). RESULTS: T-Scan analysis demonstrated a significantly higher incidence of abnormal occlusal contact points in the CT group compared with controls (p < 0.05), along with bilateral occlusal imbalance. FEA revealed that maximum von Mises stress values on the mesial surfaces were consistently higher than those on the distal surfaces in the CT group under vertical loading (p < 0.05). Abnormal contact sites contributed to increased stress on the mesial surfaces in both CT and controls. A significant intergroup difference in maximum von Mises stress was observed on the mesial surfaces (p < 0.05), whereas no significant difference was detected on the distal surfaces. CONCLUSIONS: Patients with CT exhibited bilateral occlusal imbalance, characterized by abnormal occlusal contact points on the affected teeth. Congenital morphological discrepancies represent the primary etiological factor for CT, whereas aberrant contact points further exacerbate crack progression. Early occlusal adjustment and crown-supported protection is recommended to compensate for underlying morphological abnormalities.