Levels of evidence for the outcome of endodontic surgery

Treatment of an apical cyst with platelet concentrate - a case report

Apical cysts are typically caused by dental pulp disease and are difficult to treat. In the majority of cases, surgical intervention is required. The rate of success after apical osteotomy varies between 60% and 91%. The introduction of platelet concentrates in treating chronic apical periodontitis is a promising direction for achieving quick and secure results. This article examines the healing of a sizable apical cyst after conservative surgical intervention and the application of platelet concentrate.

Present Status and Future Directions - Surgical Endodontics

Endodontic surgery encompasses several procedures for the treatment of teeth with a history of failed root canal treatment, such as root-end surgery, crown- and root resections, surgical perforation repair, and intentional replantation. Endodontic microsurgery is the evolution of the traditional apicoectomy techniques and incorporates high magnification, ultrasonic root-end preparation and root-end filling with biocompatible filling materials. Modern endodontic surgery uses the dental operating microscope, incorporates cone-beam computed tomography (CBCT) for preoperative diagnosis and treatment planning, and has adopted piezoelectric approaches to osteotomy and root manipulation. Crown- and root resection techniques have benefitted from the same technological advances. This review focuses on the current state of root-end surgery by comparing the techniques and materials applied during endodontic microsurgery to the most widely used earlier methods and materials. The most recent additions to the clinical protocol and technical improvements are discussed, and an outlook on future directions is given. While non-surgical retreatment remains the first choice to address most cases with a history of endodontic failure, modern endodontic microsurgery has become a predictable and minimally invasive alternative for the retention of natural teeth.

Endodontic Periapical Lesion: An Overview on the Etiology, Diagnosis and Current Treatment Modalities

Nonsurgical and surgical endodontic treatments have a high success rate in the treatment and prevention of apical periodontitis when carried out according to standard and accepted clinical principles. Nevertheless, endodontic periapical lesions remain in some cases, and further treatment should be considered when apical periodontitis persists. Although several treatment modalities have been proposed for endodontically treated teeth with persistent apical periodontitis, there is a need for less invasive methods with more predictable outcomes. The advantages and shortcomings of existing approaches for the diagnosis and treatment of endodontic periradicular lesions are discussed in this review.

Magnification devices for endodontic therapy

BACKGROUND

After the introduction of microsurgical principles in endodontics involving new techniques for root canal treatment, there has been a drive to enhance the visualisation of the surgical field. It is important to know if the technical advantages for the operator brought in by magnification devices such as surgical microscopes, endoscopes and magnifying loupes, are also associated with advantages for the patient in terms of improvement of clinical and radiographic outcomes. This version updates the review published in 2009.

OBJECTIVES

To evaluate and compare the effects of endodontic treatment performed with the aid of magnification devices versus endodontic treatment without magnification devices. We also aimed to compare the different magnification devices used in endodontics with one another.

SEARCH METHODS

The following electronic databases were searched: the Cochrane Oral Health Group Trials Register (to 13 October 2015), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2015, Issue 9), MEDLINE via OVID (1946 to 13 October 2015) and EMBASE via OVID (1980 to 13 October 2015). We searched the US National Institutes of Health Trials Register (http://clinicaltrials.gov) and the WHO Clinical Trials Registry Platform for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases.

SELECTION CRITERIA

We considered all randomised controlled trials (RCTs) and quasi-randomised controlled trials comparing endodontic therapy performed with versus without one or more magnification devices, as well as randomised and quasi-randomised trials comparing two or more magnification devices used as an adjunct to endodontic therapy.

DATA COLLECTION AND ANALYSIS

We conducted screening of search results independently and in duplicate. We obtained full papers for potentially relevant trials. The Cochrane Collaboration statistical guidelines were to be followed for data synthesis.

MAIN RESULTS

No trials met the inclusion criteria for this review.

AUTHORS' CONCLUSIONS

No article was identified in the current literature that satisfied the criteria for inclusion. It is unknown if and how the type of magnification device affects the treatment outcome, considering the high number of factors that may have a significant impact on the success of endodontic surgical procedure. This should be investigated by further long-term, well-designed RCTs that conform to the CONSORT statement (www.consort-statement.org/).

Outcome of endodontic surgery: a meta-analysis of the literature--Part 2: Comparison of endodontic microsurgical techniques with and without the use of higher magnification

INTRODUCTION

The aim of this study was to investigate the outcome of root-end surgery. It identifies the effect of the surgical operating microscope or the endoscope on the prognosis of endodontic surgery. The specific outcomes of contemporary root-end surgery techniques with microinstruments but only loupes or no visualization aids (contemporary root-end surgery [CRS]) were compared with endodontic microsurgery using the same instruments and materials but with high-power magnification as provided by the surgical operating microscope or the endoscope (endodontic microsurgery [EMS]). The probabilities of success for a comparison of the 2 techniques were determined by means of a meta-analysis and systematic review of the literature. The influence of the tooth type on the outcome was investigated.

METHODS

A comprehensive literature search for longitudinal studies on the outcome of root-end surgery was conducted. Three electronic databases (ie, Medline, Embase, and PubMed) were searched to identify human studies from 1966 up to October 2009 in 5 different languages (ie, English, French, German, Italian, and Spanish). Review articles and relevant articles were searched for cross-references. In addition, 5 dental and medical journals (ie, Journal of Endodontics, International Endodontic Journal, Oral Surgery Oral Medicine Oral Pathology Oral Radiology and Endodontics, Journal of Oral and Maxillofacial Surgery, and International Journal of Oral and Maxillofacial Surgery) dating back to 1975 were hand searched. Following predefined inclusion and exclusion criteria, all articles were screened by 3 independent reviewers (S.B.S., M.R.K., and F.C.S.). Relevant articles were obtained in full-text form, and raw data were extracted independently by each reviewer. After agreement among the reviewers, articles that qualified were assigned to group CRS. Articles belonging to group EMS had already been obtained for part 1 of this meta-analysis. Weighted pooled success rates and a relative risk assessment between CRS and EMS overall as well as for molars, premolars, and anteriors were calculated. A random-effects model was used for a comparison between the groups.

RESULTS

One hundred one articles were identified and obtained for final analysis. In total, 14 studies qualified according to the inclusion and exclusion criteria, 2 being represented in both groups (7 for CRS [n = 610] and 9 for EMS [n = 699]). Weighted pooled success rates calculated from extracted raw data showed an 88% positive outcome for CRS (95% confidence interval, 0.8455-0.9164) and 94% for EMS (95% confidence interval, 0.8889-0.9816). This difference was statistically significant (P < .0005). Relative risk ratio analysis showed that the probability of success for EMS was 1.07 times the probability of success for CRS. Seven studies provided information on the individual tooth type (4 for CRS [n = 457] and 3 for EMS [n = 222]). The difference in probability of success between the groups was statistically significant for molars (n = 193, P = .011). No significant difference was found for the premolar or anterior group (premolar [n = 169], P = .404; anterior [n = 277], P = .715).

CONCLUSIONS

The probability for success for EMS proved to be significantly greater than the probability for success for CRS, providing best available evidence on the influence of high-power magnification rendered by the dental operating microscope or the endoscope. Large-scale randomized clinical trials for statistically valid conclusions for current endodontic questions are needed to make informed decisions for clinical practice.

Top-cited articles in endodontic journals

INTRODUCTION

The purpose of this study was to identify the 100 top-cited articles published in journals dedicated to endodontology and analyze their characteristics to describe the quality and evolution of research in the field of endodontology.

METHODS

The Institute for Scientific Information Web of Knowledge Database and the Journal Citation Report Science Editions were used to retrieve the 100 most cited articles published in journals dedicated to endodontics. The top-cited articles were selected and analyzed with regard to journals, authors, institution, country of origin, publication title and year, number of citations, article type, study design, level of evidence, and field of study.

RESULTS

The top 100 articles were cited between 87 and 554 times. These articles appeared in 4 different journals, with more than half in the Journal of Endodontics, followed by the journals Oral Surgery Oral Medicine Oral Pathology Oral Radiology and Endodontology, the International Endodontic Journal, and Endodontics & Dental Traumatology. Forty-eight articles were published between 1990 and 1999. All articles were published in English and primarily originated from the United States (n = 52). The majority of articles were basic science articles (n = 55), followed by clinical research studies (n = 28) and nonsystematic reviews (n = 17). Uncontrolled case series with level IV of evidence and narrative reviews with level V of evidence were the most frequent types of study design. The main topics covered by the top-cited articles were microleakage and endodontic microbiology.

CONCLUSIONS

This analysis of citation rates reveals useful and interesting information about scientific progress in the field of endodontics. Basic research and observational studies published in high-impact endodontic journals had the highest citation rates.

Comparison of the success rate of endodontic treatment and implant treatment

Dentists and patients are facing a perplexity between saving a compromised tooth through endodontic treatment and restoration or by extraction and replacement with an implant. The purpose of this paper was to compare the success rates of these two treatments. Success was measured as the longevity of the tooth or implant. Studies which met strict inclusion criteria to ensure best evidence were included. Searches were performed in Ovid Medline, Pubmed, Scopus database, and the Cochrane Library. Evidence-based groups were formed following the assessment of inclusion/exclusion criteria. The overall success rates for primary endodontic, nonsurgical retreatment, and surgical treatment were (86.02%), (78.2%), and (63.4%), respectively, implants was 90.9%. In conclusion, choice between implant and endodontic therapy cannot be exclusively based on outcome as both treatments differ in the biological process, diagnostic modalities, failure patterns, and patients preferences. More research is required with improved study designs before long-term success rates can be compared.

Clinical evaluation of a modified marginal sulcular incision technique in endodontic surgery

The authors evaluated periodontal parameters following apical surgery using a new marginal sulcular incision. In 65 cases, surgical access was achieved by means of a sulcular incision technique without the involvement of the adjacent periodontia and the interproximal papillae and in 33 cases by means of a submarginal trapezoidal technique. Periodontal parameters (probing pocket depth, gingival recession, clinical attachment loss, and tooth mobility [periotest]) were recorded at baseline and after 6 months. Scar formation and the loss of papilla height were evaluated photographically. No significant changes in the attachment level and no loss of papilla height were found in either group. A slight gingival recession (0.2 +/- 0.4 mm) corresponding to the decrease in pocket depths occurred on the buccal aspect with the sulcular incision. Tooth mobility was significantly increased in both groups immediately and 6 months after surgery. Scar formation was more unfavorable with the submarginal incision.

Magnification devices for endodontic therapy

BACKGROUND

After the introduction of microsurgical principles in endodontics, involving new techniques for root canal treatment, there has been a continuous search for enhancing the visualisation of the surgical field. It would be interesting to know if the technical advantages for the operator brought in by magnification devices like surgical microscope, endoscope and magnifying loupes, are also associated with advantages for the patient, in terms of improvement of clinical and radiographic outcomes.

OBJECTIVES

The purpose of this systematic review was to evaluate and compare the effects of endodontic treatment performed with the aid of magnification devices versus endodontic treatment without magnification devices. We also aimed at comparing among them the different magnification devices used in endodontics (microscope, endoscope, magnifying loupes).

SEARCH STRATEGY

The Cochrane Oral Health Group Trials Register, CENTRAL, MEDLINE and EMBASE were searched with appropriate search strategies. Handsearching included nine dental journals. The bibliographies of relevant clinical trials and relevant articles were checked for identifying studies outside the handsearched journals. Seven manufacturers of instruments in the field of endodontics and/or endodontic surgery, as well as the authors of the identified randomised controlled trials (RCTs) were contacted in order to identify unpublished or ongoing RCTs. There were no language restrictions. The last electronic search was conducted on 2nd April 2009, and the last handsearching was undertaken on 31st January 2009.

SELECTION CRITERIA

All randomised and quasi-randomised trials comparing endodontic therapy performed with or without using one or more types of magnification device, as well as randomised and quasi-randomised trials comparing two or more magnification devices used as an adjunct to endodontic therapy were considered.

DATA COLLECTION AND ANALYSIS

Screening of studies and data extraction were conducted independently and in duplicate. The Cochrane Collaboration statistical guidelines were to be followed for data synthesis.

MAIN RESULTS

No trial could be included in the present review. All of the prospective trials that were identified, all dealing with endodontic surgery, had to be excluded for various reasons. Only one RCT was identified comparing three magnificators (magnifying loupes, surgical microscope, endoscope) in endodontic surgery. No RCT was found that compared the outcome of endodontic therapy using or without using a given magnification device.

AUTHORS' CONCLUSIONS

No objective conclusion can be drawn from the results of this review as no article was identified in the current literature that satisfied the criteria for inclusion. It is unknown if and how the type of magnification device affects the treatment outcome, considering the high number of factors that may have a significant impact on the success of endodontic surgical procedure. This should be investigated by further long-term RCTs with large sample size. Technical advantages of magnificators have been widely reported in low evidence level studies, but they should be systematically addressed to know if there can be the clinical indication for using a given magnification device for specific clinical situations, such as for molar teeth, or if they can all be used interchangeably. Well-designed RCTs should also be performed to determine the true difference in terms of treatment success rates between using or not using a magnification device in both conventional and surgical endodontic treatment, if any exist.

A prospective clinical study of periradicular surgery using mineral trioxide aggregate as a root-end filling

A prospective outcome study of periradicular surgery using microsurgical techniques and root-end filling with mineral trioxide aggregate (MTA) was performed. Nonhealing endodontically treated teeth (n = 321) were included in the study. Surgery was completed under local anesthesia using a standardized clinical protocol. Patients were recalled periodically and examined for signs and symptoms of failure. Thirty-nine teeth were lost from recall. Of the 276 teeth examined, 163 showed complete healing radiographically with no other signs and symptoms; 82 teeth had no symptoms but incomplete or uncertain healing, and 31 teeth showed nonhealing (three had persistent pain despite evidence of complete radiologic healing and eight teeth did not heal for reasons unrelated to the surgical treatment). The overall success rate was 88.8%, including all teeth with no clinical symptoms. In this study, the use of MTA as a root-end filling, following microsurgical techniques, showed a high success rate.

Implant or the natural tooth--a contemporary treatment planning dilemma?

An assessment of whether to rehabilitate a tooth requiring endodontic treatment or to replace it with a dental implant can often involve a challenging and complex decision-making process. This paper reviews the literature pertaining to both treatment modalities and identifies key issues that need careful consideration in planning the most appropriate course of care in a given clinical situation. A need to appreciate advances across both disciplines is highlighted, allowing the development of effective interdisciplinary evidence-based treatment strategies to maximize treatment outcome.

Surgical versus non-surgical endodontic re-treatment for periradicular lesions

BACKGROUND

Though success rates of endodontic initial treatment have been improving over the years, persistence of periapical disease is far from being a rare condition. The most common therapeutical options for the re-treatment of teeth with periapical pathosis are non-surgical orthograde treatment and surgical treatment. Selection between alternative treatments should be based on assessment of respective benefits (mainly healing) and risks from studies consistent with a high level of evidence.

OBJECTIVES

To test the null hypothesis of no difference in outcome between surgical and non-surgical therapy for endodontic re-treatment of periradicular lesions.

SEARCH STRATEGY

The Cochrane Oral Health Group Trials Register, CENTRAL, MEDLINE and EMBASE were searched with appropriate search strategies. Handsearching included eight dental journals. The bibliographies of relevant clinical trials and relevant articles were checked for identifying studies outside the handsearched journals. Seven manufacturers of instruments in the field of endodontics or endodontic surgery or both, as well as the authors of the identified randomised controlled trials (RCTs) were contacted in order to identify unpublished or ongoing RCTs. No language restriction was placed. The last electronic search was conducted on 3rd April 2007.

SELECTION CRITERIA

All RCTs about re-treatment of teeth with periapical pathosis in which both surgical and non-surgical approaches were used and having a follow up of at least 1 year were considered for the analysis.

DATA COLLECTION AND ANALYSIS

A quality assessment of the included RCTs was carried out and the authors were contacted for missing information. We independently extracted the data in duplicate. We followed the Cochrane Oral Health Group's statistical guidelines.

MAIN RESULTS

Three RCTs were identified, two of them reporting different data from the same clinical study. The risk of bias was judged as moderate for one study and high for the other one. 126 cases were followed up for at least 1 year, and 82 had a follow up of 4 years. At the 1-year follow up the success rate for surgical treatment was slightly better than non-surgical (risk ratio (RR) 1.13; 95% confidence interval (CI) 0.98 to 1.30). When the follow up was extended to 4 years (only one RCT made it) the outcome for the two procedures became similar.

AUTHORS' CONCLUSIONS

The finding that healing rates can be higher for cases treated surgically as compared to those treated non-surgically, at least in the short term, is based on two RCTs only. A single RCT reported that in the medium to long term healing rates for the two procedures are very similar. There is currently scarce evidence for a sound decision making process among alternative treatments for the re-treatment of a periradicular pathosis. More well-designed RCTs should be performed with follow up of at least 4 years, and with a consistent sample size, to detect a true difference in the long term between the outcomes of the two alternative treatments, if any exist.

Prospective Study of Periapically Infected Teeth Treated With Periapical Surgery Including Ultrasonic Preparation and Retrograde Intermediate Restorative Material Root-End Fillings

PURPOSE

The aim of this prospective study was to evaluate the current method of periapical surgery at the Maxillofacial Unit, Halmstad Hospital, which included ultrasonic root-end preparation and the use of intermediate restorative material as a root-end filling material.

PATIENTS AND METHODS

Fifty-five consecutive patients with a total of 56 treated teeth, within the close vicinity of the hospital, were included in the study during a period of 10 months in 2002. Teeth with advanced periodontal bone loss or presence of root fractures were excluded from the study.

RESULTS

All teeth but 1 were followed up after 1 year (12-19 months). Radiological evaluation (complete or incomplete healing) and clinical examination showed an 80% success rate. Twenty percent of the patients were stated as failures (uncertain healing and unsatisfactory healing). The success rate was highest among incisors (100%) and lowest among molars and premolars (78% and 69%, respectively).

CONCLUSION

Compared with other studies, these findings seemed to be a bit inferior regarding success rate. However, our study population was not selected for the study purpose but rather represented the true clinical variety taken care of in our practice.

The potential association between smoking and endodontic disease

The aim of this review was to analyse the literature to assess the possibility of an association between smoking and endodontic disease and the prognosis of endodontically treated teeth. The review of the prognosis of endodontically treated teeth involved taking account of any potential associations with smoking and endodontic disease and marginal periodontitis, and smoking and prosthodontic outcomes. In addition, the role of smoking in implant failure and surgical wound healing was analysed with a view to drawing parallels regarding the possible implications of smoking on the outcome of surgical endodontics. A MEDLINE and Cochrane library search including smoking and various endodontic keyword searches identified three papers which discussed the variables, and did not just mention them separately in the text. The literature demonstrates a paucity of evidence relating smoking with endodontic disease and prognosis, but nevertheless presents evidence of a possible influence on the prognosis of endodontically treated teeth in smokers and a likely increase in surgical complications. The possible merits of a smoking cessation protocol prior to surgical endodontics are also discussed.

Intentional Replantation: A Case Report

Nonsurgical retreatment and surgical endodontics are not always viable solutions to endodontic disease. Access for retreatment may be limited by posts. Surgical endodontics may be limited by anatomical features including bone thickness and nerve and sinus proximity. Anatomical limitations and complex restorations may prevent implant placement. Intentional replantation is considered by many as a procedure of last resort when nonsurgical or surgical endodontics is contra-indicated. The treatment described demonstrates intentional replantation as a procedure to be considered when endodontic procedures or a dental implant are not possible.

Retrospective Evaluation of Surgical Endodontic Treatment: Traditional versus Modern Technique

The aim of this retrospective study was to compare the outcome of surgical endodontic treatment preformed using the traditional versus modern techniques. There were 110 patients who were treated by surgical endodontic treatment between 2000 and 2002 and evaluated from their dental charts. The surgical endodontic treatment was preformed using a traditional or modern technique. The traditional technique included root-end resection with a 45 degrees bevel angle, and retrograde preparation using a carbide round bur. The modern technique included root-end resection with minimal or no bevel, and retrograde preparation using ultrasonic retro-tips with the aid of a dental operating microscope. The retrograde filling material for both techniques was intermediate restorative material. There were 71 patients with 88 treated teeth that were compatible with the inclusion criteria. Complete healing rate for the teeth treated with the modern technique (91.1%) was significantly higher than that for teeth treated using the traditional technique (44.2%) (p < 0.0001). In the traditional technique a significant (p = 0.032) negative influence of the tooth type was found. Modern surgical endodontic treatment using operative microscope and ultrasonic tips significantly improves the outcome of the therapy compared to the traditional technique.

The management of periapical lesions in endodontically treated teeth

When root canal therapy is done according to accepted clinical principles and under aseptic conditions, the success rate is generally high. However, it has also been reported that 16% to 64.5% of endodontically treated teeth are associated with periapical radiolucent lesions. There are great variations among clinicians when suggesting treatment of these failed endodontic cases. This article will discuss factors influencing treatment decisions on these particular cases, and the pros and cons of nonsurgical retreatment versus surgical retreatment. The advancement of modern endodontic microsurgery will also be discussed.

Capillary Flow Porometry to Assess the Seal Provided by Root-End Filling Materials in a Standardized and Reproducible Way

This in vitro study evaluated the root-end sealing ability of gutta-percha + AH26 (GP), Ketac-Fil, Fuji IX (FIX), tooth-colored MTA (MTA), IRM, Ketac-Fil + conditioner (Ketac-FilC), and Fuji IX + conditioner (FIXC). A total of 140 standardized bovine root sections were divided into seven groups, filled with the mentioned root-end filling materials, and, at 48 h, submitted to capillary flow porometry to assess minimum, mean flow and maximum pore diameters. Results were statistically analyzed using nonparametric Kruskal-Wallis and Dunn tests. Level of significance was set at 0.05. Using the Kruskal-Wallis tests we found that there was no significant difference between the minimum pore diameters of the different materials, but significant differences between the mean flow (p < 0.001) and maximum (p < 0.001) pore diameters could be demonstrated. For the mean flow pore diameters, there was a significant difference between FIX and all other materials, between Ketac-Fil and IRM and between Ketac-FilC and IRM. Concerning maximum pore diameters, there was a significant difference between FIX and all other materials, between Ketac-Fil and MTA, GP and IRM, FIXC and IRM, and Ketac-FilC and IRM. The data showed that each sample had leaked. Glass ionomer cements leaked more than other materials, although dentin conditioning diminished the maximum through pore diameters. This maximum pore diameter, which corresponds to the largest leak in the sample, together with the size of bacteria and their metabolites, will be indicative of the eventual leakage along the root-end filling materials.

Endodontics and Implants, a Catalog of Therapeutic Contrasts

Dentists may be faced with the choice to retain a tooth by performing endodontic therapy and restoration or to extract the tooth and replace it with an implant and restoration. The purpose of this study was to catalog areas where implant and endodontic therapies differ so as to assist dentists in making treatment decisions and in identifying areas deserving of future research. Differences in diagnostic procedures and prognostic indicators were listed. With respect to treatment outcomes, study designs, success criteria, treatment results, systematic reviews, complications, clinician expertise, and the use of patient-based measures were discussed. The need for clinically applicable consensus statements and treatment protocols was noted. It was concluded that at this time, choices between implant and endodontic therapies cannot be solely based on outcomes measurement evidence; that different modes of outcome measure frustrate direct comparison; that endodontic and implant therapies profoundly differ in many ways; that although rigorous and clearly defined outcome measures have been proposed for use in endodontic and implant outcomes studies, they are very rarely used; that long-term, large, clearly defined studies, with simple and clear outcome measures, for example survival in combination with defined treatment protocols, are needed to measure the clinical performance of endodontic and implant therapies; and it was recognized that broad outcomes data may not be sufficiently specific to directly impact clinical decision making.

Endodontic Surgery Using 2 Different Magnification Devices: Preliminary Results of a Randomized Controlled Study

PURPOSE

The introduction of microsurgical instruments and magnification devices has brought advantages in root-end management and the application of root-end filling materials. The main purpose of this prospective clinical study was to monitor the outcome of ultrasonic root-end preparation using magnification loupes or an endoscope. Tooth location and the presence of post restoration were also examined as potentially affecting the outcome.

MATERIALS AND METHODS

Teeth treated surgically showed a periradicular lesion of strictly endodontic origin. A total of 59 patients were included in the study, according to specific selection criteria. Following the reflection of a full mucoperiosteal tissue flap, residual soft tissues were curetted, root ends were resected, and root-end cavities were prepared ultrasonically with a zirconium nitrate tip, and zinc oxide EBA-reinforced cement root-end fillings were placed. Thirty-two root-end management procedures were performed using magnification loupes and 39 using an endoscope. All cases followed for a period of 1 year were classified into 3 groups (success, uncertain healing, and failure) according to radiographic and clinical criteria.

RESULTS

Of the 71 teeth evaluated at 1-year follow-up, 67 teeth (92.95%) successfully healed, 3 teeth had uncertain healing, and 2 failed. In the group using endoscopy, 94.9% of successful healing was achieved, while for the other group, 90.6% was recorded. We found no statistically significant differences in treatment results related to the arch (P = .20), post restoration (P = .21), or type of magnification device (P = .08).

CONCLUSIONS

In the present study, adherence to a strict endodontic surgical protocol and the use of modern surgical endodontic procedures, together with visual magnifications, resulted in an overall high success rate.

Levels of Evidence for the Outcome of Nonsurgical Endodontic Treatment

The purpose of this systematic review was (a) to search for clinical articles pertaining to success and failure of nonsurgical root canal therapy, and (b) to assign levels of evidence to these studies. Electronic and manual searches were conducted to identify studies published between January 1966 and September 2004 with information on the success and failure of nonsurgical root canal therapy. Articles were reviewed and graded for strength of level of evidence (LOE) from one (highest level) to five (lowest level). This review resulted in the identification of 306 clinical studies related to this topic area. Six articles were randomized controlled trials (RCTs, LOE 1). This search also identified 12 low-quality RCTs (LOE 2), 14 cohort studies (LOE 2), five case-control and eight cross sectional studies (LOE 3), four low-quality cohort studies (LOE 4), and five low-quality case-control studies (LOE 4). The majority (73) of the often-quoted "success and failure" studies were case series (LOE 4). The rest of the articles were descriptive epidemiological studies (42), case reports (114), expert opinions (18), literature reviews (4), and one meta-analysis. Based on these findings, it appears that a few high-level studies have been published in the past four decades related to the success and failure of nonsurgical root canal therapy. The data generated by this search can be used in future studies to specifically answer questions and test hypotheses relevant to the outcome of nonsurgical root canal treatment.

Essential Elements of Evidenced-Based Endodontics: Steps Involved in Conducting Clinical Research

Endodontists have the opportunity to apply relevant research findings to the care of their patients using the principles and methods of evidence-based treatment. Finding evidence begins with a specific, well-built clinical question. Once a specific question is framed, the validity and relevance of the evidence need to be appraised. The best levels of evidence can then be used to inform decisions regarding care. The purpose of this paper is to discuss the history of evidence-based treatment and to clarify the process of conducting a systematic review. The various types of research designs appropriate for answering clinical questions most commonly encountered in dental practice, including a description of the strengths and weaknesses of each, are also presented. Finally, the implications of evidence-based research on endodontics and future research are outlined.