牙撕脱的辅助治疗方法

牙再植术是牙撕脱最基本的治疗方法,主要并发症为牙髓坏死和牙根吸收。牙撕脱的临床治疗涉及到牙髓病学、牙周治疗学、创伤外科、正畸与美学等多个学科,总体疗效较差。近年来,一些相应的辅助治疗方法,在提高患牙再植成功率和预防其术后并发症方面显示了较为优良的疗效。     

Relationship between root caries and coronal decay

The relationship between caries on root surfaces and untreated coronal lesions was analyzed. A representative sample of 5028 persons was examined, their mean ages being 47.3 years for men and 47.7 for women. Poor dental health on root surfaces was associated with poor dental health in the coronal areas of the teeth. Subjects with root caries had fewer teeth and fewer fillings, more retained roots and more teeth with untreated coronal decay than did people with no root caries. Compared with the subjects without untreated coronal decay, those with from one to three decayed coronal surfaces showed an odds ratio of 4.5 of having caries on root surfaces. This ratio was 10.1 for the subjects who had more than three decayed coronal surfaces. It was concluded that factors related to the occurrence of decay are of a similar type whether caries is situated on root surfaces or in the coronal areas of the teeth, and therefore the prevention of caries in both sites may be accomplished by similar means.     

Coronal and Root Decay Experience in Older Adults in Ontario, Canada

This paper describes the coronal and root caries experience of subjects aged 50 years and older living in four communities in Ontario, Canada. The data were obtained as part of a comprehensive epidemiologic study of the oral health and treatment needs of this population. Caries experience was defined as the number of decayed and filled coronal and root surfaces per subject. Of 907 subjects interviewed and clinically examined, 78.3 percent were dentate and retained a mean of 18.9 teeth. The mean number of coronal decayed and filled surf aces was 23.9; 95.6 percent of subjects had at least one coronal DFS. The mean number of decayed and filled root surfaces was 3.6; 70.9 percent had at least one root DFS. The percent D/DFS was 3.5 for coronal and 20.0 for root caries. In linear regression analysis the number of teeth, making regular preventive visits, being born in Canada, and educational status emerged as predictors of coronal DFS. Predictors of root DFS were the number of surf aces with recession, the number of coronal DFS, the number of teeth, age, sex, and smoking status. These variables accounted for 42 percent and 35 percent of the variance in the number of coronal and root DFS, respectively.     

3种技术诊断离体第一第二磨牙根管系统对比研究

目的以透明牙技术为参照,探讨牙科数字成像系统（radiovisiography,RVG）和显微CT（micro-computed tomography,MCT）扫描两种检查技术在研究离体磨牙根管系统解剖结构中的作用,为磨牙根管治疗提供影像学依据。方法253颗离体磨牙分别摄颊舌向、近远中向RVG和行MCT扫描,再制作根管染色透明牙,应用RVG、MCT和透明牙对各牙根中上2/3、根尖1/3区根管系统结构和管间交通支进行分类统计,以评估RVG、MCT技术在根管结构诊断中的应用价值。结果透明牙、MCT两组显示牙根中上2/3区根管系统均显著优于RVG（P〈0.05）;MCT与透明牙对磨牙中上2/3区根管系统的显示差异无统计学意义（P〉0.05）。MCT、透明牙、RVG对磨牙根尖1/3区根管系统的显示差异有统计学意义（P〈0.05）,根管显示率透明牙为100%,MCT为89.84%,RVG为77.97%。结论MCT与透明牙在显示牙根中上2/3区根管系统方面基本等效;在根尖1/3区透明牙对变异细小分歧根管的显示优于MCT及RVG技术,MCT技术在根尖1/3区细小分歧的显示明显优于RVG。     

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.     

Periapical status and quality of root fillings and coronal restorations in a Danish population

AIM: The aim of this study was to investigate the quality of endodontic and coronal restorations and the association with periapical status in a Danish population. METHODOLOGY: A total of 614 randomly selected individuals (20-60+ years of age) from Aarhus County had a full-mouth radiographic examination. The quality of endodontic and coronal restorations and the periapical status of endodontically treated teeth were assessed by radiographic criteria. Root fillings were categorized as 'adequate' or 'inadequate' with regard to root filling length and lateral seal. Coronal restorations were categorized into 'adequate' and 'inadequate', defined by the absence or presence of radiographic signs of overhangs or open margins. Results were analysed statistically using the chi-squared test. RESULTS: The total number of endodontically treated teeth was 773, and 52.3% had apical periodontitis (AP). Root-filled teeth with an adequate lateral seal had a lower incidence of AP than teeth with an inadequate seal (44.3% vs. 57.8%), and teeth with an adequate root filling length were associated with a better periapical status than teeth with inadequate length of the root filling (42.0% vs. 67.6%). Similarly, adequate coronal restorations were associated with better periapical status than inadequate restorations (48.0% vs. 63.9%). When both root filling and coronal restoration quality were assessed, the incidence of AP ranged from 31.2% (optimal quality) to 78.3% (all parameters scored as inadequate). CONCLUSIONS: Inadequate root canal and coronal restorations were associated with an increased incidence of AP.     

Periapical status and quality of root fillings and coronal restorations in an adult Spanish population

AIM: To investigate the quality of root fillings and coronal restorations and their association with periapical status in an adult Spanish population. METHODOLOGY: A total of 180 subjects, aged 37.1 +/- 15.7 years, who presented as new patients at the Faculty of Dentistry, Seville, Spain, were examined. All participants underwent a full-mouth radiographic survey incorporating 14 periapical radiographs. The periapical region of all root filled teeth, excluding third molars, were examined. The technical quality of root fillings was evaluated in terms of length in relation to the root apex and lateral adaptation to the canal wall. Radiographic signs of overhang or open margins associated with coronal restorations were also evaluated. Periapical status was assessed using the Periapical Index score. Statistical analyses were conducted using the Cohen's kappa test and logistic regression. RESULTS: The total number of root filled teeth was 93, and 60 (64.5%) had apical periodontitis (AP). Presence of AP in root filled teeth was associated with inadequate adaptation of the filling (OR = 2.29; P = 0.06), inadequate length of the root filling (OR = 2.44; P = 0.048), and with poor radiographic quality of the coronal restoration (OR = 2.38; P = 0.054). Only 34.4% of the root fillings were adequate from a technical perspective. When both root fillings and coronal restorations were adequate the incidence of AP decreased to 31.3% (OR = 5.50; P < 0.01). CONCLUSIONS: The incidence of AP in root filled teeth was high. Many root fillings were technically unsatisfactory. Adequate root fillings and coronal restorations were associated with a lower incidence of AP; an adequate root filling had a more substantial impact on the outcome of treatment than the quality of the coronal restoration.     

Conservative endodontic treatment of teeth fractured in the middle or apical part of the root

Abstract –  According to treatment type, root-fractured teeth with pulp necrosis or exposed pulps were divided into five groups, group 1: 17 teeth in which the root canal of the coronal fragment only was filled with gutta-percha (GP); group 2: seven teeth in which the root canals of the coronal and apical fragments were both filled with GP; group 3: 19 teeth in which the coronal fragment was filled with GP and the apical fragment was surgically removed; group 4: 68 teeth where the root canal of the coronal fragment was treated with calcium hydroxide and subsequently filled with GP; and group 5: five vital teeth with root and concomitant crown fractures in which the exposed pulps were treated by partial pulpotomy. The frequency of periodontal healing was 76% in group 1, zero in group 2, 68% in group 3 and 86% in group 4. Compared with groups 1 and 2 combined, healing in group 4 was significantly more frequent. In groups 1, 2 and 4, failures occurred significantly more often in teeth showing overfilling, i.e. protrusion of GP into the space between the fragments, compared with teeth without overfilling. All five teeth in group 5 showed healing. It was concluded that root canal filling with GP of the coronal fragment only, with or without surgical removal of the apical fragment, can be successful in selected cases. Treatment of the root canal with calcium hydroxide followed by GP filling appears to be the treatment of choice in root-fractured non-vital teeth. Partial pulpotomy of exposed pulps in five teeth showed results similar to root-unfractured teeth with pulp exposure treated with this technique.     

Investigation of the effect of the coronal restoration quality on the composition of the root canal microflora in teeth with apical periodontitis by means of T-RFLP analysis

AIM: To investigate the effect of the radiographic and clinical quality of coronal restorations on the composition of the root canal flora of teeth with necrotic pulps and teeth with root fillings associated with apical periodontitis. METHODOLOGY: Twenty-eight necrotic pulps and 35 root filled canals with signs of apical periodontitis were studied. Both the coronal filling (presence of radiographically or clinically deficient margins and/or secondary caries) and the root filling (homogeneity and length) were scored. Bacterial root canal samples were taken with sterile paper points under rubber dam and using measures to prevent contamination. A DNA-based nonculture bacterial identification technique was used, namely terminal restriction fragment length polymorphism (T-RFLP) analysis. RESULTS: Twelve samples were negative for bacterial DNA. A total of 33 different terminal restriction fragments (TRFs) were detected. The Fusobacterium nucleatum/Streptococcus mitis group was the most frequently encountered TRF. The mean number of TRFs per necrotic pulp was 6.2 and 5.8 for the groups with acceptable and unacceptable coronal restorations, respectively. This difference was not significant. In the root filled group, these values (respectively, 5.2 and 8.6) were statistically significantly different (P < 0.05). The following parameters in root filled teeth had no significant influence on the mean numbers of TRFs detected: the length and homogeneity of the root filling and the type of tooth (anterior-premolar-molar). CONCLUSION: T-RFLP allowed the rapid assessment of bacterial biodiversity in root canal samples. The technique revealed the presence of bacteria that have rarely been described in the root canals of teeth with apical periodontitis. Biodiversity in the root filled group was high, as compared with culture-dependent studies where monoinfections were more frequently reported. Only in root filled teeth did defective coronal restorations have a statistically significant influence on the mean numbers of detected TRFs per sample.     

Periapical health related to the quality of coronal restorations and root fillings

AIMS: To evaluate the impact of the quality of coronal restorations scored on a clinical and radiographic basis and the quality of root fillings on periapical health. METHODOLOGY: Periapical radiographs were taken of 745 root-filled teeth, randomly selected from patients attending the Ghent University Dental School. The teeth had not received restorative treatment in the previous year. The coronal status was scored both clinically according to modified Ryge's criteria, and radiographically by evaluating the presence of signs of marginal leakage or decay. The quality of the root filling was scored according to criteria of length and homogeneity and the periapical status was categorized on the basis of presence or absence of radiographic signs of apical periodontitis. The relationship between coronal status, quality of root filling and periapical health was determined. The data were analyzed using Chi2 test, Odds ratio, Spearman's r(S) and logistic regression. RESULTS: Thirty-three percent of the teeth had apical periodontitis as diagnosed radiographically. Teeth with good and poor coronal restorations scored clinically had apical periodontitis in 31.1 and 36.8%, respectively; this difference was not statistically significant. The quality of the coronal restorations scored radiographically had a statistically significant influence on the periapical condition (P<0.001) with apical periodontitis in 23.8 and 49.1%, respectively, for acceptable and unacceptable restorations. Marginal decay did not influence the periapical status. Teeth restored without a base under the coronal filling had apical periodontitis in 41.3%, whereas teeth with a base had significantly less (P<0.005) apical periodontitis (25.9%). Composite-restored teeth exhibited apical periodontitis in 40.5% of cases whilst amalgam-restored teeth had apical periodontitis in 28.4% of cases; this difference was statistically significant (P<0.01). Root-canal posts had no influence on periapical health. The length and homogeneity of the root-canal fillings had a significant influence (P<0.01 and P<0.001, respectively) on the presence of apical periodontitis, as well as the quality of the coronal restoration scored radiographically (P<0.001). CONCLUSION: The importance of a good coronal restoration, as well as of a good root filling should be emphasized as the technical quality of both influencing the periapical status.     

Caries prevalence in Dutch elderly people

In 1986 a nationwide oral survey was carried out in the Netherlands. One of the aims of this study was to assess the prevalence of oral diseases in adults. The present paper describes the prevalence of coronal and root caries in elderly Dutch subjects (45-74 years). The oldest age group (65-74 years) had, on average, the least number of teeth remaining; the posterior oral segment contained fewer teeth than the anterior segment. The anterior segment had the higher percentage of teeth with coronal caries and the posterior segment a higher percentage of filled teeth. The reverse was the case for root caries; a higher percentage of teeth had root caries in the posterior segment and the anterior segment a higher percentage of filled teeth.     

Endodontic failure caused by inadequate restorative procedures: review and treatment recommendations

A review of the literature was performed to determine whether prompt placement of coronal restorations, including sealing and placement of posts and cores, can positively influence the long-term prognosis of teeth after root canal therapy. Both hand and MEDLINE searches were employed to identify peer-reviewed articles on radicular apical integrity after coronal restorations, especially where root canal space was used for post and core fabrication. A total of 41 articles published between 1969 and 1999 (the majority from the 1990s) were reviewed. The literature suggests that the prognosis of root canal-treated teeth can be improved by sealing the canal and minimizing the leakage of oral fluids and bacteria into the periradicular areas as soon as possible after the completion of root canal therapy.     

An in vitro investigation of the bulk flow of fluid through apical foramina during simulated tooth extraction: a potential confounder in microbiological studies?

Aim The ‘pumping action’ induced during tooth extraction may cause bacteria suspended in tissue fluids to be transposed from one anatomical compartment to another. Apart from causing bacteraemia, this may lead to inaccuracies in studies evaluating the presence and distribution of bacteria in and around tooth apices. The aim was to investigate the bulk flow of fluid through apical foramina during simulated extraction of teeth in an in vitro model. The influence of the presence or absence of a coronal restoration was also evaluated. Methodology Twenty extracted single‐rooted, human, mature, permanent teeth were used. Standard access cavities were prepared and the root canals located. Standardized micrographs of the apical foramina were obtained and their area (µm²) was calculated by image analysis software. The teeth were then set and sealed into polyvinylsiloxane (rubber base) impression material. Crystal violet dye was inoculated into the coronal half of the root canal system. Tooth extraction movements were simulated in the impression matrix and the leakage of dyes with and without the presence of a coronal restoration was examined. The procedure was repeated, following application of safranin dye in a coronal trough within the simulated rubber base gingival margin at the CEJ. The results were analysed statistically with the independent‐samples t‐test and the McNemar test. Results In the absence of a coronal restoration crystal violet leaked out of the apical foramina in 18/20 teeth; conversely safranin leaked into the teeth through the apical foramina in 11/20 cases when applied to the external root surface. In the presence of an intact coronal restoration crystal violet dye leaked out in 6/20 teeth and conversely safranin leaked into 7/20 teeth. The presence of a coronal restoration significantly reduced (P = 0.002) dye leakage out of the root canal system. No associations were found for leakage of dye into the root canal system when applied externally. In addition, the amount of dye leakage was positively correlated with the area of the apical foramen in the presence of a coronal restoration (P = 0.009). Conclusion The presence of a coronal restoration significantly reduced leakage of dye out of the apical foramen. Microbiological studies on root canals and periapical lesions using extracted teeth should take potential contamination from this source into account.     

Models for coronal caries and root fragments in an elderly population.

A random sample of 809 dentate, home-dwelling people 65 years of age or older participated in a study to determine the prevalence of dental diseases in the elderly. Part of the study investigated the determinants of coronal caries and root fragments in these older adults. Using a wide array of potentially explanatory variables available, logistic regression models were developed to identify relationships between these variables and coronal caries and root fragments. The variables with the most explanatory power in the coronal caries model were the presence of decayed root surfaces, lower salivary flow rate, lack of regular dental care and an interaction variable including race and a perception of financial well-being. When a subsequent model was created that did not include decayed root surfaces or root fragments as potential explanatory variables, an additional variable relating to self-perception of mouth appearance emerged. The strongest variables in the model for root fragments were episodic (vs. regular) dental visits, presence of root caries, lack of replacement for lost teeth, high levels of Streptococcus mutans and number of teeth present in the mouth.     

Prevalence of Apical Periodontitis in Root Canal–Treated Teeth From an Urban French Population: Influence of the Quality of Root Canal Fillings and Coronal Restorations

This cross-sectional study determined the prevalence of apical periodontitis in 1035 root canal–treated teeth from adult French patients and investigated the influence of the quality of canal fillings and coronal restorations on the periradicular status. Periapical radiographs were used for analyses, and teeth were classified as healthy or diseased according to the periapical index scoring system. Overall, the prevalence of apical periodontitis in root canal–treated teeth was 33%. Only 19% of the teeth had endodontic treatments rated as adequate. The success rate (number of healthy teeth) for cases with adequate endodontic treatment was 91%, which was significantly higher when compared with teeth with inadequate treatment (61%). Teeth with adequate restorations had significantly decreased prevalence of apical periodontitis (29%) as compared with teeth with inadequate restorations (41%). The combination of adequate endodontic treatment and adequate restorations yielded the highest success rate (93.5%). The quality of the endodontic treatment was the most important factor for success, although the quality of the coronal restoration also influenced the treatment outcome.     

Modified Apexification Procedure for Immature Permanent Teeth with a Necrotic Pulp/Apical Periodontitis: A Case Series

The current American Association of Endodontists clinical considerations for a regenerative endodontic procedure state that a regenerative procedure is suitable for immature permanent teeth with necrotic pulp when the pulp space is not needed for a post/core in the final restoration. Therefore, many immature permanent teeth with necrotic pulp that have sustained a substantial loss of coronal tooth structure either from caries or trauma are treated by apexification or mineral trioxide aggregate/Biodentine (Septodent, Lancaster, PA) apical barrier techniques in which no further root maturation would occur. This case series presents 10 immature permanent teeth with necrotic pulp in which a post/core was likely required in the future for adequate coronal restoration because of loss of substantial coronal tooth structure and a modified apexification procedure was used. All 10 cases after the modified apexification procedure showed no clinical symptoms/signs and showed radiographic evidence of healed/healing of periapical lesion after a 2-year review. Eight cases showed increased thickness of the apical root canal walls, increased apical root length, and apical closure. The overall percentage change in root length was 7.52%, in root width at the apical one third it was 18.89%, and in radiographic root area it was 15.04% at the 24- to 72-month follow-up period. This modified apexification procedure allows for the tooth to be restored with a post/core if required for the final restoration in the future as well as continued root development.     

Polymicrobial coronal leakage of super EBA root-end fillings following two methods of root-end preparation

The aim of this study was to compose in vitro coronal leakage of a super EBA root-end filling material after two root-end cavity preparation techniques. A mixed anaerobic microbial marker was used. Forty-five extracted human teeth with straight, single root canals were prepared chemo-mechanically to a size 40 master apical file. The teeth were divided into experimental groups (35 teeth) and control groups (10 teeth). Forty teeth (35 experimental teeth and five negative control teeth) were obturated by lateral condensation of cold gutta-percha with Tubliseal EWT sealer. The remaining five teeth were not obturated and served as positive controls. These teeth were stored for 6 months in artificial saliva. The apical 3-4 mm of each root was resected perpendicular to the long axis of the root and a root-end cavity prepared to a depth of 3 mm using either a size 008 rosehead burr or an ultrasonic retroprep tip. Freshly mixed EBA cement was placed into the root-end cavity. The entire root surface of each tooth, except the cutting surface of the apical end, was sealed with nail varnish. The coronal part of each root canal was sealed with the cut end of a tube and placed in a bottle containing sterile Brain Heart Infusion Broth (BHIB). A marker consisting of Anaerobic streptococci and Fusobacterium nucleatum in BHIB was placed in each coronal chamber at 7-day intervals and daily observations were made for bacterial growth in the apical chamber for 60 days. All positive control teeth exhibited bacterial leakage within 48 h, whilst the apical chamber of negative control teeth remained uncontaminated throughout the test period. Fifty-nine percent ( n = 10) of the specimens prepared with a burr showed leakage after 90 days, whilst only 22% ( n = 4) of the ultrasonically prepared group showed leakage after the same time. The group prepared with ultrasonic tips showed statistically significant less specimens with leakage ( P < 0.05) than the group prepared with burrs.     

An evaluation of endodontically treated vertical root fractured teeth: impact of operative procedures

Vertical root fractures of endodontically treated teeth are a frustrating complication that leads to extraction. The aim of the current survey was to evaluate the role of operative procedures in the etiology of this complication. A total of 154 endodontically treated vertical root fractured teeth were cleaned and washed after extraction and maintained in individual vials. Periapical radiographs before extraction, clinical findings and previous operative procedures were recorded. A post was observed in 95 teeth (61.7%), with 66 of these ending at the coronal third of the root. Most were screw posts of the Dentatus type (n = 64) and tapered cast posts (n = 14). A full crown was observed in 118 teeth, and 65 of these (55%) were extracted between 1 to 5 yr after final restoration. In 24 crowned teeth extraction was conducted within 1 yr after restoration and in 28 teeth after >5 years. It was concluded that post placement and root canal treatment are the major etiological factors for root fractures. Because signs and symptoms can appear years after the operative procedures in the root have been completed, coronal restorations would not interfere with the correct clinical diagnosis of vertical root fractures. Frequent recalls are recommended to diagnose vertical root fractures early, especially in susceptible teeth, such as premolars and mesial roots of mandibular molars.     

Different clinical outcomes following root fractures of adjacent incisors: a case report

AIM: To report different patterns of root fracture healing in adjacent maxillary central incisors with distinct post-treatment outcomes. SUMMARY: To describe the case of a 12-year-old girl who presented with an avulsed coronal fragment of tooth 11 and root fractures in the middle thirds of teeth 11 and 21. Four months after initial treatment, she was referred for specialized endodontic care. Tooth 11 presented no clinical or radiographic signs of pulp breakdown. However a sinus tract was found related to the middle root third of tooth 21, indicating pulp necrosis in the coronal fragment. The coronal fragment was root filled and periapical surgery was performed to remove the apical fragment. Twelve months after the clinical procedures and 16 months after trauma, hard tissue healing was evident in tooth 11 region. Bone healing was also satisfactory in the periapical region of tooth 21. *Even adjacent teeth may display different reaction patterns after trauma. *The prognosis of root fractures is variable and different clinical approach may be required to preserve teeth with fractured roots.     

An in vitro study of the coronal leakage of two root canal sealers using an obligate anaerobe microbial marker

The aim of this in vitro study was to investigate the coronal leakage of obligate anaerobes into root canals obturated with lateral condensation of cold guttapercha with two root canal sealers. Sixty extracted human teeth with straight, single root canals were prepared using the modified double-flared technique with balanced force under copious irrigation until the master apical file was size 40. The teeth were divided randomly into experimental groups (40 teeth) and control groups (20 teeth). In the experimental groups, 20 teeth were obturated with lateral condensation of cold gutta-percha and AH26 sealer and 20 teeth were obturated with the same technique using TubliSeal EWT sealer. In the control groups, 10 teeth were obturated with the same technique either with AH26 or TubliSeal EWT sealer. These teeth were completely sealed to serve as negative controls. The remaining 10 teeth were not obturated and served as positive controls. The root surface of each tooth was sealed with nail varnish except the apical 2 mm. The coronal part of each root canal was sealed with the cut end of polypropylene tube and placed in a glass bottle containing sterile Fastidious Anaerobe Broth (FAB). Aliquots of 0.5 mL of FAB were injected into the polypropylene tube and the model system was centrifuged at 168 g. An inoculum of Fusobacterium nucleatum in FAB was placed in each coronal chamber at 7-day intervals and daily observations were made for bacterial growth in the apical reservoir for 12 weeks. All positive control teeth showed bacterial leakage within a week, while the negative control teeth remained uncon-taminated throughout the test period. All the experimental teeth exhibited leakage of bacterial metabolites within 12 weeks, ranging from 1 to 12 weeks. The mean time for complete leakage in the AH26 and the TubliSeal EWT groups was 8.4 and 8.2 weeks respectively. There was no statistically significant difference (P > 0.05) in leakage between the AH26 and the TubliSeal EWT groups.