Minju Song

Prognostic factors for clinical outcomes in endodontic microsurgery: a retrospective study.

INTRODUCTION This retrospective study examined the potential prognostic factors on the outcome after endodontic microsurgery and compared the predictors of isolated endodontic lesion with those of both isolated endodontic lesions and endodontic-periodontal lesions. METHODS 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. Surgical procedures were performed by the endodontic faculty and residents. 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). RESULTS Of 907 cases, 491 were retained at follow-up. At the 0.05 level of significance, age, sex (female), tooth position (anterior), root-filling length (inadequate), [corrected] lesion type (endodontic lesion), root-end filling material (mineral trioxide aggregate and Super EBA; Harry J. Bosworth, Skokie, IL), and restoration at follow-up appeared to have a positive effect on the outcome. On the other hand, with an isolated endodontic lesion, the tooth position (anterior), root-filling length (inadequate), [corrected] and restoration at follow-up were significant factors at the 95% confidence level. CONCLUSIONS Under the control of the significant variables in logistic regression, the potential prognostic factors on the outcome were sex, tooth position, lesion type, and root-end filling material. On the other hand, the tooth position was a pure predictor of an endodontic lesion affecting the clinical outcome.

Outcomes of Endodontic Micro-resurgery: A Prospective Clinical Study

INTRODUCTION This study examined the outcomes of endodontic resurgery by using current microsurgery techniques on failed teeth with previous endodontic surgery. Another goal was to determine any significant outcome predictors of endodontic surgery by determining the causes of failure in the first endodontic surgery. METHODS The data were collected from patients in the Department of Conservative Dentistry at the Dental College, Yonsei University in Seoul, Korea between March 2001 and May 2009. All 54 teeth that required surgical retreatment were included in this study. All surgical procedures were performed by using an operating microscope and biocompatible root-end filling materials such as mineral trioxide aggregate (MTA) or Super EBA. The patients were recalled every 6 months for 2 years and every year thereafter to assess the clinical and radiographic signs of healing. RESULTS The recall rate was 77.8% (42 of 54 patients). Of the 42 cases recalled, 39 cases were included in the success category, giving an overall success rate of 92.9%. The most common possible causes of failure were no root-end filling and incorrect root-end preparation. CONCLUSIONS The use of microsurgical techniques and biocompatible materials such as MTA and Super-EBA resulted in a high clinical success rate, even in endodontic resurgery.

Analysis of the cause of failure in nonsurgical endodontic treatment by microscopic inspection during endodontic microsurgery.

INTRODUCTION This study examined the clinical causes of failure and the limitation of a previous endodontic treatment by an inspection of the root apex and resected root surface at 26× magnification during endodontic microsurgery. METHODS The data were collected from patients in the Department of Conservative Dentistry at the Dental College, Yonsei University in Seoul, Korea between March 2001 and January 2011. All root-filled cases with symptomatic or asymptomatic apical periodontitis were enrolled in this study. All surgical procedures were performed by using an operating microscope. The surface of the apical root to be resected or the resected root surface after methylene blue staining was examined during the surgical procedure and recorded carefully with 26× magnification to determine the state of the previous endodontic treatment by using an operating microscope. RESULTS Among the 557 cases with periapical surgery, 493 teeth were included in this study. With the exclusion of unknown cases, the most common possible cause of failure was perceived leakage around the canal filling material (30.4%), followed by a missing canal (19.7%), underfilling (14.2%), anatomical complexity (8.7%), overfilling (3.0%), iatrogenic problems (2.8%), apical calculus (1.8%), and cracks (1.2%). The frequency of possible failure causes differed according to the tooth position (P < .001). CONCLUSIONS An appreciation of the root canal anatomy by using an operating microscope in nonsurgical endodontic treatment can make the prognosis more predictable and favorable.

Long-term Outcome of the Cases Classified as Successes Based on Short-term Follow-up in Endodontic Microsurgery

INTRODUCTION In a previous study, we evaluated the outcomes of endodontic microsurgery by comparing the healing success of cases involving a lesion of endodontic origin with cases involving a lesion of combined endodontic-periodontal origin. Of the 188 teeth over the 5-year period, 172 (91.5%) were considered to be successes. The purpose of this study was to evaluate the outcomes, up to 10 years, of the cases that were classified as successes in the previous study. METHODS The 172 cases that were considered to have successful outcomes in the previous study were included. Patients were followed up every 6 months for 2 years and every year up to 10 years. On every follow-up visit, clinical and radiographic evaluations were performed according to the same criteria as in the original study by the same 2 examiners. RESULTS A follow-up rate of 60.5% (104/172 cases) was obtained. Of the 104 followed-up cases, 97 cases were included in the successful group, 91 with complete healing and 6 with incomplete healing. The overall maintained success rate was 93.3%. The failure group, which meant a reversal to disease, included 7 cases with unsatisfactory healing. CONCLUSIONS In this study, 93.3% of endodontic microsurgery cases that were considered healed in a prior 5-year study remained healed after more than 6 years.

Pulp-dentin Regeneration: Current State and Future Prospects

The goal of regenerative endodontics is to reinstate normal pulp function in necrotic and infected teeth that would result in reestablishment of protective functions, including innate pulp immunity, pulp repair through mineralization, and pulp sensibility. In the unique microenvironment of the dental pulp, the triad of tissue engineering would require infection control, biomaterials, and stem cells. Although revascularization is successful in resolving apical periodontitis, multiple studies suggest that it alone does not support pulp-dentin regeneration. More recently, cell-based approaches in endodontic regeneration based on pulpal mesenchymal stem cells (MSCs) have demonstrated promising results in terms of pulp-dentin regeneration in vivo through autologous transplantation. Although pulpal regeneration requires the cell-based approach, several challenges in clinical translation must be overcome—including aging-associated phenotypic changes in pulpal MSCs, availability of tissue sources, and safety and regulation involved with expansion of MSCs in laboratories. Allotransplantation of MSCs may alleviate some of these obstacles, although the long-term stability of MSCs and efficacy in pulp-dentin regeneration demand further investigation. For an alternative source of MSCs, our laboratory developed induced MSCs (iMSCs) from primary human keratinocytes through epithelial-mesenchymal transition by modulating the epithelial plasticity genes. Initially, we showed that overexpression of ΔNp63α, a major isoform of the p63 gene, led to epithelial-mesenchymal transition and acquisition of stem characteristics. More recently, iMSCs were generated by transient knockdown of all p63 isoforms through siRNA, further simplifying the protocol and resolving the potential safety issues of viral vectors. These cells may be useful for patients who lack tissue sources for endogenous MSCs. Further research will elucidate the level of potency of these iMSCs and assess their transdifferentiation capacities into functional odontoblasts when transplanted into the root canal microenvironment.

Periapical status related to the quality of coronal restorations and root fillings in a Korean population.

INTRODUCTION The purpose of this study was to assess the prevalence of apical periodontitis in root canal-treated teeth from the Korean population and to evaluate the relationship between the quality of root canal fillings and coronal restorations and the periapical status of these teeth. METHODS Full-mouth periapical radiographs at the Dental Hospital of Yonsei University, Seoul, South Korea, were examined. A total of 1030 endodontically treated teeth restored with full veneer crown-type restorations were evaluated by 2 independent examiners. Teeth were classified as healthy or diseased according to the periapical status. The quality of endodontic treatment and coronal restorations were also classified via radiographic and clinical evaluation. The data were analyzed using the chi-square test and logistic regression. RESULTS Forty-one percent of all endodontically treated teeth were classified as diseased. Approximately 35.6% of the teeth had endodontic treatments that were rated as adequate. The diseased teeth rate for cases with adequate endodontic treatment was 24.5%, which was significantly lower when compared with teeth with inadequate endodontic treatment (49.9%). The number of teeth with adequate coronal restorations was 706 (68.5%). Teeth with adequate coronal restorations had a significantly decreased prevalence of diseased teeth (34.7%) compared with teeth with inadequate coronal restorations (54.3%). Teeth with both adequate root fillings and restorations showed a significantly better outcome (82.3%) than the others, and teeth with both inadequate root fillings and restorations showed a significantly worse outcome (41.2%) than the others. CONCLUSIONS Data from this Korean population showed a relatively high prevalence of apical periodontitis. The quality of endodontic treatment and coronal restorations were of equal importance and were strong independent predictors of the periapical status.

Cytotoxicity of newly developed pozzolan cement and other root-end filling materials on human periodontal ligament cell

Objectives The purpose of this study was to evaluate in vitro cytotoxicity of the pozzolan cement and other root-end filling materials using human periodontal ligament cell. Materials and Methods Endocem (Maruchi), white ProRoot MTA (Dentsply), white Angelus MTA (Angelus), and Super EBA (Bosworth Co.) were tested after set completely in an incubator at 37℃ for 7 days, Endocem was tested in two ways: 1) immediately after mixing (fresh specimens) and 2) after setting completely like other experimental materials. The methods for assessment included light microscopic examination, cell counting and WST-1 assay on human periodontal ligament cell. Results In the results of microscopic examination and cell counting, Super EBA showed significantly lower viable cell than any other groups (p < 0.05). As the results of WST-1 assay, compared with untreated control group, there was no significant cell viability of the Endocem group. However, the fresh mixed Endocem group had significantly less cell viability. The cells exposed to ProRoot MTA and Angelus MTA showed the highest viability, whereas the cells exposed to Super EBA displayed the lowest viability (p < 0.05). Conclusions The cytotoxicity of the pozzolan cement (Endocem) was comparable with ProRoot MTA and Angelus MTA. Considering the difficult manipulation and long setting time of ProRoot MTA and Angelus MTA, Endocem can be used as the alternative of retrofilling material.

The Role of ORAI1 in the Odontogenic Differentiation of Human Dental Pulp Stem Cells

Pulp capping, or placing dental materials directly onto the vital pulp tissues of affected teeth, is a dental procedure that aims to regenerate reparative dentin. Several pulp capping materials are clinically being used, and calcium ion (Ca2+) released from these materials is known to mediate reparative dentin formation. ORAI1 is an essential pore subunit of store-operated Ca2+ entry (SOCE), which is a major Ca2+ influx pathway in most nonexcitable cells. Here, we evaluated the role of ORAI1 in mediating the odontogenic differentiation and mineralization of dental pulp stem cells (DPSCs). During the odontogenic differentiation of DPSCs, the expression of ORAI1 increased in a time-dependent manner. DPSCs knocked down with ORAI1 shRNA (DPSC/ORAI1sh) or overexpressed with dominant negative mutant ORAI1E106Q (DPSC/E106Q) exhibited the inhibition of Ca2+ influx and suppression of odontogenic differentiation and mineralization as demonstrated by alkaline phosphatase (ALP) activity/staining as well as alizarin red S staining when compared with DPSCs of their respective control groups (DPSC/CTLsh and DPSC/CTL). The gene expression for odontogenic differentiation markers such as osteocalcin, bone sialoprotein, and dentin matrix protein 1 (DMP1) was also suppressed. When DPSC/CTL or DPSC/E106Q cells were subcutaneously transplanted into nude mice, DPSC/CTL cells induced mineralized tissue formation with significant increases in ALP and DMP1 staining in vivo, whereas DPSC/E106Q cells did not. Collectively, our data showed that ORAI1 plays critical roles in the odontogenic differentiation and mineralization of DPSCs by regulating Ca2+ influx and that ORAI1 may be a therapeutic target to enhance reparative dentin formation.

Comparison of Clinical Outcomes of Endodontic Microsurgery: 1 Year versus Long-term Follow-up

INTRODUCTION The purpose of this study was to examine and compare the clinical outcome of endodontic microsurgery after 1 year of follow-up and over a period of 4 years. METHODS The database of the Department of Conservative Dentistry, Yonsei University, Seoul, South Korea, was searched for patients who had undergone endodontic microsurgery and had been evaluated 1 year after surgery and over a period of 4 years. Two examiners independently evaluated the postoperative radiographs taken 1 year after surgery and over a period of 4 years using Ruds criteria. To analyze and compare the success rate based on the observation period, the McNemar test was performed with a significance level of 0.05. RESULTS The study included 115 cases. Using Ruds criteria, the overall success rate of cases with 4 or more years of follow-up was 87.8% compared with 91.3% at 1 year of follow-up. There was no significant difference between the follow-up periods (P = .344). CONCLUSIONS There was no significant difference in the clinical outcome after endodontic microsurgery when comparing 1-year follow-up periods with longer follow-up periods.

The influence of bone tissue deficiency on the outcome of endodontic microsurgery: a prospective study.

INTRODUCTION This study assessed the influence of deficiencies of the periapical and marginal bone tissue on clinical outcomes after endodontic microsurgery. METHODS Data were collected from the Microscope Center of the Department of Conservative Dentistry at the Dental College of Yonsei University, Seoul, South Korea, between August 2004 and March 2011. In total, 199 teeth that required endodontic surgery were included in the study. During the surgical procedure, deficiencies of the periapical and marginal bone tissue were measured immediately before the flap was repositioned. The patients were recalled 6 months and 1 year after the surgical procedure to assess the clinical and radiographic signs of healing. The Students t test or the Mann-Whitney U test and logistic regression were performed to evaluate the parameters. Significant associations between the outcome and all the evaluation parameters were analyzed using the Pearson chi-square test or the Fishers exact test with a significance level of 0.05. RESULTS A recall rate of 67.8% (135/199 teeth) was obtained. The height of the buccal bone plate was the only significant predictor (P = .040) of the healing outcome, suggesting that teeth with a buccal bone plate >3 mm presented a higher success rate than teeth with a buccal bone plate that was ≤3 mm high (94.3% vs 68.8%, P < .001). CONCLUSIONS These data suggest that a favorable prognosis can be expected when teeth are covered with a buccal bone plate that is >3 mm in height regardless of the amount of marginal bone loss.