Survival Rate of Teeth with a C-shaped Canal after Intentional Replantation: A Study of 41 Cases for up to 11 Years.

INTRODUCTION: Teeth with a C-shaped canal have been regarded as a challenge for nonsurgical root canal treatment (RCT) and apical microsurgery because of their anatomic variations and low accessibility. For such teeth, intentional replantation might be a treatment option. The purpose of this study was to investigate the prognostic factors for the clinical outcome of intentionally replanted teeth with a C-shaped canal. METHODS: We retrospectively investigated patients who had undergone intentional tooth replantation at the Department of Conservative Dentistry, Yonsei University Dental Hospital, Seoul, Korea, from June 2002 to November 2015. Consequently, 41 intentionally replanted teeth with C-shaped canals were identified. The cumulative survival rate and related prognostic factors were assessed based on clinical and radiographic examination using survival analysis. RESULTS: The cumulative survival rate of intentionally replanted teeth with a C-shaped canal was 83.4% at 4 years and 73.0% at 11 years postoperatively. Based on Cox proportional hazard regression analysis, extraoral time (≤15 minutes vs >15 minutes) and retrofilling material (ProRoot MTA [Dentsply, Tulsa, OK] vs others) were significantly associated with tooth survival (P < .05). CONCLUSIONS: Extraoral time exceeding 15 minutes and the use of ProRoot MTA as a retrofilling material were significantly associated with a lower survival of intentionally replanted teeth with C-shaped canals. With improved clinical procedures based on an understanding of the prognostic factors, intentional replantation would be a favorable treatment option for treating teeth with a C-shaped canal.

Influence of Size and Volume of Periapical Lesions on the Outcome of Endodontic Microsurgery: 3-Dimensional Analysis Using Cone-beam Computed Tomography.

INTRODUCTION: The purpose of this study was to examine the size, volume, and other parameters of preoperative periapical lesions measured from cone-beam computed tomographic (CBCT) images as potential prognostic factors in endodontic microsurgery. METHODS: A clinical database was searched for patients who had received endodontic microsurgery with preoperative CBCT examination between March 2010 and December 2014. The CBCT images were analyzed with the OnDemand3D software program (Cybermed, Seoul, South Korea). The mesiodistal (Lx), apicocoronal (Ly), and buccolingual (Lz) diameter and the volume (V) of the periapical lesions, destruction of the cortical bone, and height of the buccal bone plate (Lb) were measured independently by 2 examiners. The outcome was classified as a success or failure based on the clinical and radiographic evaluation at least 1 year after the operation. Univariate analyses using the chi-square or Fisher exact test were performed to show the correlation of the outcomes with variables to identify the potential predisposing factors. Multivariate analysis using a logistic regression model was performed with the associated variables. RESULTS: Ninety-five cases were evaluated after a period of at least 1 year, and 2 were extracted before the 1-year follow-up. The interexaminer agreements were excellent for the linear and volume measurement of the preoperative periapical lesion. A lesion volume above 50 mm(3) was found to be a significant negative predictor in the univariate analysis (P = .028) and the logistic regression model (P = .038). CONCLUSIONS: Within the limitations of this study, the volume of the preoperative periapical lesion had a significant effect on the outcome of endodontic microsurgery. It is suggested that further studies on endodontic microsurgery should be performed and that quantitative measurements using CBCT imaging may be useful for the analyses.

Healing of Horizontal Intra-alveolar Root Fractures after Endodontic Treatment with Mineral Trioxide Aggregate.

INTRODUCTION: The purpose of this retrospective study was to evaluate the healing type and assess the outcome of horizontal intra-alveolar root fractures after endodontic treatment with mineral trioxide aggregate (MTA) as filling material. METHODS: The clinical database of the Department of Conservative Dentistry at Yonsei University Dental Hospital, Seoul, Korea, was searched for patients with histories of intra-alveolar root fractures and endodontic treatments with MTA between October 2005 and September 2014. Radiographic healing at the fracture line was evaluated independently by 2 examiners and was classified into 4 types according to Andreasen and Hjørting-Hansen. RESULTS: Of the 22 root-fractured teeth that received endodontic treatment with MTA, 19 cases participated in the follow-up after a period of at least 3 months. Seventeen of the 19 teeth (89.5%) exhibited healing of the root fractures. For each healing type, 7 teeth (36.8%) showed healing with calcified tissue, 8 teeth (42.1%) showed interposition of connective tissue, 2 teeth (10.5%) showed interposition of connective tissue and bone, and 2 teeth (10.5%) showed interposition of granulation tissue without healing. CONCLUSIONS: Within the limitations of this study, intra-alveolar root fractures showed satisfactory healing outcomes after endodontic treatment with MTA. MTA could be considered to be suitable filling material for the endodontic treatment of horizontal intra-alveolar root fractures.

Smear layer production by 3 rotary reamers with different cutting blade designs in straight root canals: a scanning electron microscopic study.

OBJECTIVES: The design of the cutting blade of rotary instruments may affect the outcome of root canal instrumentation in terms of cleanliness. The aim of this scanning electron microscopic study was to compare the quality and amount of smear layer generated in the apical third of straight root canals by 2 rotary nickel-titanium reamers and 1 rotary steel reamer with different cutting blade designs. STUDY DESIGN: Seventy intact, single-rooted human mandibular premolars with straight, fully developed roots were selected for this study. Before instrumentation, the cervical portion of all teeth was removed by using a microtome (Isomet), leaving 13-mm-long roots. Automated preparation was performed with ProFile (n = 20) and Hero 642 (n = 20) reamers by using the crown-down technique and with a stainless steel engine reamer (Mani; n = 20) by using a reaming motion. All root canals were instrumented to No. 40. A control group (pulp extirpation with barbed broaches; n = 10) was also included. Irrigation with 3 mL of a 1% sodium hypochlorite (NaOCl) solution was performed after each instrumentation. After the instrumentation, each root was split longitudinally, and a scanning electron microscope was used to examine the selected areas of the canal walls at the apical third from 2 different perspectives. A 4-category scoring system for smear layer was used, and the resulting scores were statistically analyzed. RESULTS: The least smear layer remained in the Hero 642 group at the selected apical third of straight root canals (P < .05). However, all instruments left a smear layer. The surface texture of the smear layer, in addition to the depth and the frequency of packed materials into the dentinal tubules, varied with instrument type. CONCLUSION: These data revealed that the design of the cutting blade of rotary instruments can affect root canal cleanliness in straight root canals. This information may be useful in the selection of nickel-titanium rotary reamers.