Prognostic factors for clinical outcomes in endodontic microsurgey : three cohort studies and a randomized controlled study

Abstract

This dissertation aimed to examine the potential prognostic factors generally and investigate the effect of specific factors, root-end filling materials, and deficiency of periapical and marginal bone tissue, on the outcome of endodontic microsurgery. 1. Prognostic factors in endodontic microsurgery: a retrospective and a prospective cohort studies The first purpose of this study was to examine the potential prognostic factors on the outcome of endodontic microsurgery and compared the predictors of an isolated endodontic lesion with those of both an isolated endodontic lesion and endodontic-periodontal lesion retrospectively and prospectively. For a retrospective study, the data were collected from patients with a history of endodontic microsurgery performed between August 2004 and December 2008 and at least 1 year before being evaluated. Of the 907 cases, 491 were retained at follow-up. For a prospective study, data were collected between March 2001 and March 2011, a total number of 584 teeth requiring endodontic surgery were included in the study. Of the 584 cases treated, 431 cases came for recall after a period of at least 12 months. After surgery, an operation record form was made with the preoperative, intraoperative, and postoperative factors from the clinical and radiographic measures. For statistical analysis of the predisposing factors, the dependent variable was the dichotomous outcome (ie, success vs failure).As a results, sex (female), tooth position (anterior), arch type (maxilla), lesion type (isolated endodontic lesion), and root-end filling material (mineral trioxide aggregate (MTA) and Super ethoxy-benzoic acid (Super EBA) were found to have a positive effect on the outcome. An isolated endodontic lesion might reduce the effect of many variables in the outcome of endodontic microsurgery, the tooth position (anterior), arch type (maxilla) and type of restoration (single/splinted crown, short bridge and RPD abutment) were found to be a pure positive predictor of an endodontic lesion affecting the clinical outcome. 2. MTA and Super EBA as root-end filling materials: a prospective randomized controlled studyThe second purpose was to evaluate the clinical outcomes of endodontic microsurgery when Super EBA and MTA were used as the root-end filling materials in a prospective randomized controlled study. Of the 388 teeth eligible for endodontic microsurgery between February 2003 and October 2010, 128 teeth were excluded from the study, and 260 teeth were randomly assigned to either the Super EBA group or the MTA group with equal numbers using the ‘‘minimization method.’’ Endodontic microsurgical procedures were performed according to the Yonsei protocol reported in a previous study and were carried out by a single operator. The patients were followed up at 3, 6, and 12 months. The primary outcome measure was the change in the apical bone density at 12 months, and the secondary outcome measures were the presence of clinical symptoms or abnormal findings at 12 months. A total of 192 teeth were examined at the 12-month follow-up; 102 teeth were in the Super EBA group, and 90 were in the MTA group. The overall success rate was 94.3%, with a success rate of 95.6% (86/90 teeth) for MTA and 93.1% (95/102 teeth) for Super EBA. The statistical analysis of the success rate results did not show any significant difference between the groups (P =0.472)3. Influence of deficiency of periapical and marginal bone tissue on clinical outcome: a prospective cohort studyThe last purpose was to assess the influence of deficiency of periapical and marginal bone tissue on clinical outcome after endodontic microsurgery.A total number of 199 teeth requiring endodontic surgery were included in the study between August 2004 and March 2011. During the surgical procedure, deficiencies of periapical and marginal bone tissue were measured just before the flap repositioned. With regard to the evaluated parameters, t-test and Mann-Whitney U test were performed to find differences between the 2 groups (success versus failure) for all parameters. In addition to these analyses, logistic regression model was performed with significant parameters which are assumed to be relevant clinically and statistically. And all measurements categorized, significant associations between the outcome and all the evaluation parameters were examined by a Pearson chi-square test or Fisher’s exact test with a significance level of 0.05. A recall rate of 67.8% (135 of 199 teeth) was obtained and overall success rate was 85.2% (115 of 135 teeth). Absence or presence of buccal bone plate is potential predictors of the healing outcome, teeth with complete loss of buccal bone plate showed lower healing rate than those which are not (70.4% vs 88.9%, P = 0.029). And teeth with the buccal bone plate with > 3 mm showed a higher success rate than teeth with ≤ 3 mm (94.3% vs 66.7%, P = 0.002). Factors influencing the outcomes of endodontic microsurgery may be diverse, but standardization of procedures can minimized its range. Patient and tooth-related factors such as sex, periodontal status and toot position are found to be prognostic, root-end filling material and type of postoperative restoration were also considered. More randomized controlled studies or prospective cohort studies concerning are needed to confirm these findings.