Related Factors Affecting the Survival Status of the Cracked Teeth After Root Canal Therapy: A Retrospective Study

Introduction: Cracked teeth are an important cause of pulp diseases and tooth loss. When a cracked tooth causes a pulp reaction, it can lead to tooth pain. Root canal therapy (RCT) is an effective treatment for cracked teeth with pulp exposure. However, few studies have investigated the factors affecting the prognosis of patients receiving this treatment. This retrospective study aimed to analyze the potential factors that may influence the survival rate of cracked teeth with pulp exposure after RCT. Methods A total of 221 cracked teeth that had undergone a complete RCT and met the inclusion criteria were included in the final analysis. The evaluated factors included 10 preoperative factors: age, gender, arch type, tooth type, initial diagnosis (pulpitis or periapical periodontitis), location and direction of cracks, periodontal probing depth, bite test and percussion test results, crown integrity, and 4 postoperative factors: whether full crown restoration was performed after RCT, the frequency of chewing hard foods with the affected side, whether there was a habit of rapidly alternating hot and cold foods, and unilateral chewing habit. Statistical analysis was performed via Cox multivariate proportional hazards modeling. Results The follow-up duration for 221 cracked teeth ranged from 1–8 years, with an overall tooth survival rate of 76.5%. The maxillary first molar was the most frequently (39.4%) affected tooth. Multivariate analysis revealed that preoperative periapical lesions (HR = 3.887; 95% CI, 1.864–8.106; P  < 0.001), deeper probing depths (per 1 mm. HR = 1.682; 95% CI, 1.181–2.395; P  = .004), absence of full crown restoration (HR = 7.052; 95% CI, 3.782–13.15; P  < .001), and unilateral chewing on the affected side (HR = 2.116; 95% CI, 1.165–3.843; P  = .014) were the independent influencing factors of cracked teeth after RCT. Conclusion Preoperative deeper probing depth, the presence of periapical lesions, the absence of postoperative full crown restoration, and the occurrence of postoperative unilateral chewing on the affected side were significantly associated with a reduced survival rate of cracked teeth after RCT.