[Long-term treatment outcome and influencing factors of teeth receiving modified crown lengthening].

Objective: To observe the long-term clinical treatment outcome and the influencing factors of the outcome for the teeth receiving modified crown lengthening surgery combined with root canal treatment and post-core crown restoration. To summarize the clinical guidelines of modified crown lengthening surgery in selection of indications and for mulation of treatment planning. Methods: Fifty-seven patients with a total of 67 teeth receiving modified crown lengthening surgery combined with root canal treatment and post-core crown restoration for at least a 6 months' follow-up period between July 2004 and July 2013 were recruited in this retrospective study by phone call interviews. The patients' clinical outcomes were evaluated by the combination of clinical examination, radiograph and questionnaire regarding patient-reported outcome of the last follow up (≥9 months post modified crown lengthening surgery and ≥6 months after definite crown restorations). All of the treated teeth were classified into two groups, group A (teeth with good clinical treatment outcome) and group B (teeth with poor clinical treatment outcome), based on the defined criteria including patients' satisfaction with the function and esthetics of the teeth and absence of periodontal, endodontic and prosthodontic complications. The potential influencing factors of clinical treatment outcome were also determined by Logistic regression analysis. Results: Vertical root fracture in 1 tooth was found on its periapical film and the tooth was deemed hopeless. Thus, the survival rate is 99% (66/67) for the multidisciplinary treatment approach. Seventy-two percent (48/67) of the teeth achieved good clinical treatment outcome and 28% (19/67) of the teeth developed one or several complications. In group B (teeth with poor clinical treatment), 16 out of teeth exhibited periodontal complications with bleeding on probing (BOP) positive mostly found. Logistic regression analysis demonstrated that plaque control (OR=21.392, P=0.014), edge form (OR=7.610, P=0.011), and smoking experience (OR=7.315, P=0.018) were the risk factors influencing the clinical treatment outcome of modified crown lengthening surgery combined with root canal treatment and post-core restoration. Conclusions: Modified crown lengthening surgery combined with root canal treatment and post-core restoration has a good and stable clinical effect in the observational time of 6-114 months. Plaque control, smoking status and edge form of the tooth appeared to be the influencing factors of this multidisciplinary treatment approach.目的：观察改良牙冠延长术联合根管治疗及桩核冠修复治疗后的长期临床疗效，并探索可能影响临床治疗效果的相关风险因素，以期为临床适应证的选择及治疗计划的制定提供参考。方法：纳入2004年7月至2013年7月于北京大学口腔医学院·口腔医院牙周科就诊并接受改良牙冠延长术联合根管治疗及桩核冠修复后≥6个月的患者57例、患牙67颗，通过电话随访召回复查，根据末次随访复查时（改良牙冠延长术后≥9个月且永久性修复≥6个月时）的临床检查、影像学检查和问卷调查结果，按拟定标准包括患者无主观症状、对患牙功能及美学效果满意，患牙牙周、牙体及修复体状况良好等将患牙分为临床疗效良好组和临床疗效欠佳组，对影响两组患牙长期临床疗效的因素进行统计学分析。结果：纳入研究的67颗患牙中1颗因出现根纵裂需要拔除，患牙治疗后6至114个月时的存留率为99%（66/67），其中临床疗效良好的患牙占72%（48/67），临床疗效欠佳的患牙占28%（19/67）。临床疗效欠佳组内出现牙周并发症的患牙占16/19。Logistic回归分析结果显示，菌斑控制情况（OR=21.392，P=0.014）、断端形态（OR=7.610，P=0.011）及吸烟状态（OR=7.315，P=0.018）是影响改良牙冠延长术联合根管治疗及桩核冠修复长期临床疗效的风险因素。结论：改良牙冠延长术联合桩核冠修复后6至114个月的观察时间内临床效果良好稳定；患者菌斑控制情况、是否吸烟及患牙断端形态影响改良牙冠延长术的长期临床疗效。.