Management of endodontic failures

Effect of handpiece light and material used in pulp chamber on dentin removal during root canal retreatment

This study evaluated the effect of the use of glass ionomer cement (GIC) and flowable bulk-fill resin composite (BFRC) for filling pulp chambers and the type of high-speed handpiece light used on dentin removal during access preparation for endodontic retreatment in molar teeth. Twenty maxillary molars were treated endodontically. BFRC (Opus Bulk Fill Flow APS, FGM) was used to fill the pulp chamber and replace coronal dentin (n = 10). In the remaining teeth, the pulp chamber was filled with GIC (Maxion R, FGM). Conventional resin composite (Opallis, FGM) was used to restore the enamel layer in all teeth. The samples in each group were divided into two subgroups, and the root canals were reaccessed using a handpiece with white or ultraviolet light. The teeth were scanned using micro-CT before and after root canal reaccess. The dentin volume removed was calculated and analyzed using 2-way analysis of variance and Tukey's test (α = 0.05). The crown and pulp chamber locations with dentin removal are described using frequency distribution. During the access, fewer pulp chamber walls were affected and a lower volume of dentin was removed from the pulpal floor in the group restored with GIC than in the group restored with BFRC. No effect was observed on the coronal dentin walls with respect to the filling protocols and type of light used. For dentin removal from the pulp chamber, handpieces with white light performed better than those with ultraviolet light, irrespective of the filling protocol used. The use of GIC to fill the pulp chamber and use of white handpiece light reduced dentin removal from the pulpal floor and resulted in fewer affected dentin walls.

Evaluation of Related Factors in the Failure of Endodontically Treated Teeth: A Cross-sectional Study

INTRODUCTION

The aim of this study was to review the factors related to the failure and extraction of unsuccessful endodontically treated teeth.

METHODS

A total of 1000 teeth treated with nonsurgical root canal therapy were analyzed, and the following information was recorded for each patient: reasons for failure and extraction, type of tooth, presence and type of coronal restoration, smoking status, age, gender, and level of education. One main reason was recorded for each failed tooth. The associations between reasons for failure, patient, and tooth were tested by using χ² analysis.

RESULTS

Of the 1000 endodontically failed teeth analyzed in this study, 28.1% (n = 281) were extracted, 66% (n = 660) were re-treated, and 5.9% (n = 59) were treated with apical surgery. Among the reasons for failure, restorative and endodontic reasons were seen most frequently (43.9%, n = 439), whereas orthodontic reasons were seldom seen (0.1%, n = 1). The most common reason for extraction was for prosthetic reasons (40.8%), and perforation/stripping was the least common (2.9%). The mandibular first molars were the most frequently extracted teeth (27.4%, n = 77).

CONCLUSIONS

The most common reason for the extraction of endodontically treated teeth was for prosthetic reasons. Among the reasons for failure, restorative and endodontic reasons were the most frequently seen, and orthodontic reasons were the most seldom. The teeth that failed most frequently were mandibular first molars, and the teeth that failed least frequently were maxillary third molars. The most common reason for the extraction of failed endodontically treated teeth was for prosthetic reasons.

Endodontic re-treatment associated with the elimination of amalgam root-end filling through sinus tracts: a report of two cases

Two patients presented with complaints of recurrent drainage of purulent exudate from sinus tracts, inflammation and pain after endodontic re-treatment of the maxillary left (Case 1) and right (Case 2) lateral incisors. The periapical lesions persisted after apical curettage, apicectomy and root-end filling with silver amalgam. Radiographic examination exposed the poor quality of the endodontic treatments and the silver amalgam root-end fillings, which were associated with periapical radiolucent areas in both teeth. The sinus tract persisted after root canal cleaning and shaping, followed by a calcium hydroxide root canal dressing. The root-end fillings were periapically dislodged with endodontic K-files, and showed progressive displacement by sinus tracts up to elimination in the oral cavity. Follow ups of 42 and 65 months post procedure revealed clinical disappearance of the symptoms, sinus tracts and exudates, and radiographs revealed that the repair process of the periapical radiolucent areas was quite advanced.

Removal of Two Types of Root Canal Filling Material Using Pulsed Nd:YAG Laser Irradiation

OBJECTIVE

The aim of this study was to examine the usefulness of a pulsed Nd:YAG laser in removing two types of endodontic obturation material from the root canal in vitro.

BACKGROUND DATA

Recently, a fine flexible glass fiber made of quartz has been developed to transmit the laser beam more effectively and permit its concentration in a specific area. This has increased the potential usefulness of the Nd:YAG laser in root canal treatment.

METHODS

The time required for removing the root canal obturation material (Gutta-percha cones and, Sealapex or AH26) by means of either Nd:YAG laser irradiation or a conventional method (Gates Glidden drills and K files) was measured. Contact microradiography was used to assess the radiopacity of the root canals before and after the removal of obturation material. The surfaces of the root canal after removal of the obturation materials were also observed by scanning electron microscopy.

RESULTS

Although none of the methods used in this study resulted in complete removal of debris from the root canal wall, the time required for the removal of any of the root canal obturation materials using laser ablation was significantly shorter than that required using the conventional method (p < 0.05). It appeared that some orifices of the dentinal tubules were blocked with melted dentin following laser irradiation.

CONCLUSIONS

Nd:YAG laser irradiation is an effective tool for the removal of root canal obturation materials, and may offer advantages over the conventional method.

Radiographic evaluation of cases referred for surgical endodontics

AIM

The aim of this study is to test the hypothesis that more patients with failed root-canal treatment or other endodontic problems are referred for periradicular surgery rather than nonsurgical re-treatment.

METHODOLOGY

Three sets of 100 periapical radiographs representing typical cases referred for surgical treatment were collected in three departments of oral and maxillo-facial surgery situated in different parts of the Netherlands. Of these, a total of 278 radiographs were evaluated to determine whether endodontic surgery was indicated or whether the primary endodontic treatment or endodontic re-treatment was a realistic option. An oral and maxillo-facial surgeon, an endodontist and a general dental practitioner viewed the radiograph independently under standard conditions.

RESULTS

Overall, orthograde root-canal (re-)treatment was considered possible in 63% of the cases. The results differed between the three examiners with the oral surgeon reporting that 41% of cases were amenable to conventional treatment, for the general dental practitioner and the endodontists the figures were 67 and 80%, respectively.

CONCLUSIONS

Based on these observations, it is concluded that most of the teeth referred for surgical treatment to an oral surgeon could be treated by orthograde nonsurgical root-canal treatment.

The outcome of endodontic resurgery: a systematic review

AIM

The aim of this paper is to establish an outcome standard for the assessment of healing radiographically after resurgery of persistent periradicular lesions by systematically reviewing the results from published studies.

METHODOLOGY

The systematic review process requires the definition of predetermined criteria delineating the inclusion parameters of studies reviewed. Of 42 papers that were reviewed, eight qualified for inclusion. A weighted-average was calculated from the results taken from the eight eligible, peer-reviewed studies, published between 1970 and 1997.

RESULTS

Three hundred and thirty patients out of 2375 (14%) from the included studies underwent resurgery for failure of healing as determined radiographically. Of this population, 35.7% healed successfully after resurgery, 26.3% healed with uncertain results and 38% did not heal at the one-year follow-up.

CONCLUSIONS

Although there is nearly equal distribution of results between all categories, a 35.7% rate of healing as assessed radiographically is essentially equivalent to the 38% failure rate. This paper will allow an evaluation of current research results to establish an outcome standard and enable techniques and filling materials to be evaluated and compared. Furthermore, the outcome standard can assist in defining demographic and aetiological factors that contribute to the potential outcome of resurgery cases.

Management Of Post-Treatment Endodontic Disease: A Current Concept Of Case Selection

Over 30% of root filled teeth in the population present with endodontic infective disease, which has either persisted or emerged after treatment. Management of these "failed" cases is a challenge to the clinician, at the levels of diagnosis, case selection, communication and decision, and that is even before techniques are considered. Diagnosis should differentiate between endodontic and other aetiologies, and focus on the site of infection. Case selection should be based on how best to control the infection, but also on the benefit-risk balance of the alternative treatment modalities, the attitudes of the patient and the capability of the clinician. All of the above must be communicated to the patient, who then should make the informed decision regarding the selected treatment. This article discusses the treatment rationale, diagnosis, case selection and communication related to post-treatment endodontic disease.

Endodontic retreatment decisions: no consensus

AIM

The objectives of the present study were to: (i) evaluate the consensus, if any, amongst dental schools, students and their instructors managing the same clinical cases, all of which involved endodontically treated teeth; and (ii) determine the predominant proposed treatment option.

METHODOLOGY

Final year students, endodontic staff members and instructors of 10 European dental schools were surveyed as decision makers. Fourteen different radiographic cases of root canal treated teeth accompanied by a short clinical history were presented to them in a uniform format. For each case the decision makers were requested to: (i) choose only one out of nine treatment alternatives proposed, from 'no treatment' to 'extraction' via 'retreatment' and 'surgery' (ii) assess on two 5-point scales: the difficulty of making a decision, and the technical complexity of the retreatment procedure.

RESULTS

The results indicate wide inter- and also intra-school disagreements in the clinical management of root canal treated teeth. Analysis of variance showed that the main source of variation was the 'school effect', explaining 1.8% (NS) to 18.6% (P < 0.0001) of the treatment variations. No other factor explained as much variance. Decision difficulty was moderately correlated to technical complexity (Pearsons' r ranging from 0.19 to 0.35, P < 0.0001).

CONCLUSIONS

No clear consensus occurred amongst and within dental schools concerning the clinical management of the 14 cases. The lack of consensus amongst schools seems to be due mainly to chance or uncertainty, but can be partly explained by the 'school effect'.

Efficacy, cleaning ability and safety of different devices for gutta-percha removal in root canal retreatment

The purpose of this study was to evaluate the efficacy, cleaning ability and safety of five different devices and techniques to remove gutta-percha root canal fillings. One hundred and twenty extracted single-rooted anterior and premolar teeth were enlarged to ISO size 35 and obturated with laterally condensed gutta-percha using AH 26 as the sealer. Removal of gutta-percha was performed with the following devices and techniques: (a) Gates-Glidden and Hedstrom files, (b) only Hedstrom files, (c) Hedstrom files and chloroform, (d) the Endotec and Hedstrom files, and (e) the XGP drill and Hedstrom files. The following data were recorded: time taken to reach the desired working length, time required for the removal of the gutta-percha, and the amount of material extruded apically. The teeth were split longitudinally and photographed. Cleanliness of the root canal walls was scored using the projected slides with a total magnification of approximately 70x. The fastest technique to reach the working length was using the XGP drill (e), followed by the Gates-Glidden drills (a), Hedstrom files and chloroform (c), and the Endotec device (d). The use of Hedstrom files (b) without any additional support proved to be most time-consuming. Differences were statistically significant (U-test, P > 0.05) between the rotary devices and the manual techniques. Time for complete removal of gutta-percha was again shortest with the XGP drills (e), followed by the Gates-Glidden burs (a), the Endotec device (d), Hedstrom files with chloroform (c), and Hedstrom files alone (b). The XGP burs and the Gates-Glidden drills worked significantly faster than the other techniques. The amount of debris and filling material extruded apically in most cases did not exceed 0.1 mg. No significant differences could be detected between the groups (U-test, P > 0.05). Root canal cleanliness proved best following the use of Hedstrom files without additional support (b) and the Gates-Glidden drills (a), followed by Hedstrom files in combination with chloroform (c), the XGP-gutta-percha remover (e), and the Endotec device (d). When using the XGP two instrument fractures occurred in the apical parts of the root canals preventing further instrumentation to the apical foramen. When using the Gates-Glidden burs four instrument fractures occurred, but all fragments could be removed with forceps immediately. The results suggest that the XGP gutta-percha remover and the Gates-Glidden drills are efficient and time saving devices to remove gutta-percha but include a certain risk of instrument breakage and may leave some filling material inside the root canal. The best root canal cleanliness was achieved with Hedstrom files alone which, on the other hand, were shown to be the most time-consuming.

Retreatment decision making by a group of general dental practitioners in Germany

The aim of this study was to evaluate whether retreatment of root fillings was judged necessary or not and which kind of retreatment was preferred among a group of general dental practitioners in Germany. A questionnaire comprising 19 cases of endodontically treated teeth with different case histories and several treatment options was sent to all general practitioners in Göttingen (Germany). The cases included teeth with periapical radiolucencies, pain, apical resorption, under- and overfilling, and unfilled root canals. Results obtained from 43 questionnaires returned indicate that non-intervention or further radiographic monitoring were preferred by the majority of general practitioners in 10 of 19 cases, even in the presence of periapical pathosis. Only five cases were judged to require conservative endodontic retreatment and, in four cases, root resection. The results revealed large inter- and intraindividual discrepancies in the estimation of endodontic retreatment need.

Retreatment or radiographic monitoring in endodontics

The aim of this clinical study was to assess 1032 endodontically treated roots in relation to: (i) the success rate of retreatment (612 roots)--only cases that had recall examinations of 6 months or longer were evaluated; (ii) the influence of various factors on the technical and clinical results of the retreatment; and (iii) the consequences of radiographic monitoring of 420 asymptomatic roots when the root filling was radiographically deficient (short, overextended and/or permeable root fillings). Technical assessment of the retreatment showed that the root was adequately sealed in 52.3% of cases, the root filling was improved in 33.8%, was identical with the initial treatment in 11.1% and was worse than the first treatment in 2.8% of the canals. Clinical assessment of the retreatment of symptomatic roots showed that 71.8% of the retreatments were judged successful, 18.9% showed some healing and 9.3% had failed. The initial size of the periapical lesion, the use of rubber dam, the root filling technique and the apical level of the root filling had a statistically significant influence on the result of the retreatment. Monitoring radiographically (median time span 6 years) led to maintenance of the status quo in 94.8% of cases, healing in 2.4% and failure in 2.8% of the canals. Retreatment is clearly indicated when periapical radiolucency, clinical signs and/or symptoms are present with relative success of up to 91%. When no or little radiographic evidence of periapical pathology was present, when clinical signs and symptoms were absent or when the root filling was radiographically deficient, radiographic monitoring led to complications in only a limited number of cases.

KEYWORDS

clinical decision, endodontic retreatment, radiographic evaluation.

Methods for removing metal obstructions from the root canal

The removal of metallic obstructions is an important part of endodontic retreatment procedures and encounters a number of serious problems. Sometimes removal procedures are extremely easy and can be performed in rather short time, but often it is a very tedious and time-consuming operation with a high number of failures, especially with fractured instruments. Using special devices such as the Masserannkit, the Canal-Finder-System, or ultrasonic systems some fractured instrument cases can be managed successfully. The retreatment of dowel-obturated root canals or failing silver cone cases has a good prognosis and a fairly good success rate. The Masserannkit, post pullers, the Canal-Finder-System and ultrasonic systems have been shown to be helpful devices in removal of root posts and silver cones. Additionally a large number of special devices and techniques for the removal of metal obstructions from the root canal have been described in the literature and will be critically reviewed.