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

Questions and answers in evidence-based patient care

Evidence-based healthcare has become the mainstream of current healthcare practices, yet there seem to be many misunderstandings concerning this concept. This paper reviews several aspects of the concept of evidence-based healthcare in a simple question-and-answer format. The areas considered include: the significance of the evidence-based concept in clinical practice, the method of conducting a detailed electronic search of the literature, and the interpretation and application of research evidence to patients and immediate clinical applications.

Parallel post-space preparation in different tooth types ex vivo: deviation from the canal centre and remaining dentine thickness

AIM

To determine the deviation of parallel-sided twist-drills during post-channel preparation and relate this to tooth type and position.

METHODOLOGY

Human teeth with single root canals were selected: maxillary second premolars (group i); maxillary lateral incisors (group ii); mandibular canines (group iii); mandibular first premolars (group iv; all groups n = 16). The teeth were reduced to 17 mm length by sectioning the crown, and the root canals prepared and filled. Microradiographs were made in two directions. The teeth were individually embedded in a gypsum jaw and placed in a phantom head. Two operators performed parallel post-space preparation (12 mm length, 1.25 mm diameter) to the following protocol: gutta-percha removal with Gates Glidden drills numbers 2 and 3 and post-space enlargement with parallel drills numbers 3, 4 and 5, consecutively. Subsequently, microradiographs were re-exposed. The original and post-operative microradiographs were digitized and superimposed, and deviation of the post-space from the filled canal and remaining dentine thickness measured.

RESULTS

Overall, the mean deviation was 0.07 mm to the mesial (95% CI: 0.01-0.12), and 0.27 mm to the buccal (95% CI: 0.18-0.35). Group ii had significantly more buccal deviation than other groups (P = 0.004-0.008). A remaining dentine thickness of <0.5 mm occurred 16 times in 14 teeth, and of <1 mm occurred 97 times in 52 teeth.

CONCLUSIONS

Deviation during parallel post-preparation was common, predominantly in mesial and buccal directions, especially in maxillary incisors. This deviation increased the risk of perforation considerably.

Leakage of 4 resin-based root-canal sealers used with a single-cone technique

OBJECTIVE

The aim of this study was to measure leakage of 4 resin-based sealers.

STUDY DESIGN

Four groups of premolars (n = 60) were prepared using GT Rotary files and the crown-down technique and filled by the single-cone technique with AH26, AHPlus, EndoREZ, and an experimental MBP as sealer. Leakage was measured using the fluid filtration method after 15, 30, and 60 days and determined as microL/min(-1) x 10 psi.

RESULTS

Statistical analysis by ANOVA and Tukey HSD test indicated that root fillings with AH Plus and the MBP showed lower leakage values after 15 days (P < .05). At 30 days, AH26 presented higher leakage values when compared to other sealers (P < .05). At 60 days, MBP and AH Plus presented the lower leakage values, differing significantly from EndoREZ (P < .05).

CONCLUSION

It was observed that AH Plus and the experimental MBP showed lower leakage after 60 days than AH 26 and EndoREZ.

Association between intra-radicular posts and periapical lesions in endodontically treated teeth

Introduction:

A significant number of endodontically treated teeth restored with posts have associated periapical lesions, and several authors have discussed the probable causes of the development of these. Attention has been focused on restorative procedures performed after endodontic treatment and their association with the prognosis of endodontic therapy because a number of root-filled teeth will require post- and core-retained restorations.

Purpose:

The purpose of this study was to evaluate, by examination of periapical radiographs, whether the placement of intra-radicular posts in endodontically treated teeth may act as a risk factor for development of periapical lesions.

Material and Methods:

This case-control study analyzed periapical radiographs of 72 endodontically treated teeth with coronal restorations. All radiographs were obtained from a single private practice. Specimens were assigned to 2 groups: Group 1 (control) was composed of teeth without periapical lesions and Group 2 (case) was composed of teeth with periapical lesions. The number of teeth with and without posts in each group was recorded. Three calibrated examiners analyzed the radiographs visually under X4 magnification.

Results:

In Group 1, 28 (65.1%) out of 43 teeth were restored with posts. In Group 2, 24 (82.8%) out of 29 teeth had intra-radicular posts. The interpretation of chi-square test showed that these percentages were not significantly different (x²=2.687; p=0.101). Odds ratio was 2.571 (0.8158.118), which indicates that there was no statistically significant association between periapical lesions and posts.

Conclusion:

Intra-radicular posts placed in endodontically treated teeth were not a significant risk factor for development of periapical lesions in the practice where the cohort of patients was treated.

Sealing properties of two contemporary single-cone obturation systems

AIM

To compare the sealing of root canals filled with two single-cone obturation systems and a warm vertical compaction technique.

METHODOLOGY

Forty-two single-rooted teeth were decoronated to obtain 17-mm-long root segments. The root canals were cleaned and shaped to size 40, 0.06 taper and filled with: (i) warm vertical compaction with AH Plus (control); (ii) ActiV GP and (iii) GuttaFlow with single master cones. Leakage was evaluated by fluid filtration at 10 psi before root resection, and after 3, 6, 9 and 12 mm apical resections. Repeated measures anovas on ranks and Dunn's multiple comparison tests were performed to examine differences in fluid flow rates amongst different resection lengths for each filling technique. The surface and interior aspects of glass-ionomer filler-coated ActiV GP gutta-percha cones was evaluated with SEM.

RESULTS

No statistical difference amongst the filling techniques was seen at 0 and 3 mm root resections. ActiV GP and GuttaFlow exhibited more leakage than AH Plus at 6, 9 and 12 mm resections. AH Plus recorded the best overall results. A nonhomogeneous coating of glass-ionomer fillers on the surface of ActiV GP cones was detected.

CONCLUSIONS

The two single-cone techniques examined are as effective in sealing the apex as AH Plus when the latter was used with warm vertical compaction. It is further hypothesized that the inferior coronal seal of these single-cone techniques may be improved with the placement of accessory cones to reduce sealer thickness or an immediate coronal adhesive restoration.

Treatment planning the endodontic case

Following a definitive diagnosis of the need for root canal treatment, the treatment planning stage should be straightforward if a logical sequence of decision-making is followed. Very few contra-indications exist for providing root canal treatment, but the planning must include several aspects. Firstly, is root canal treatment best for the patient to maintain a functional dentition long term? Secondly, who should provide the treatment? Thirdly, what are the restorative options that will ensure the best long-term prognosis? The sequencing of root canal treatment generally occurs early in a typical treatment plan, and prompt restoration after treatment is crucial to long-term survival of the tooth.

Effect of Chemical Irrigants on the Bond Strength of a Self-Etching Adhesive to Pulp Chamber Dentin

The aim of this study was to evaluate the influence of endodontic irrigants on adhesion to pulp chamber dentin. Seventy crowns of bovine incisors were cut to expose the pulp chamber. Specimens were divided into seven groups, according to the irrigant solution used: G1, 0.9% sodium chlorite (control); G2, 5.25% NaOCl; G3, 5.25% NaOCl + 17% EDTA; G4, 2% chlorhexidine solution; G5, 2% CHX solution + 17% EDTA; G6, 2% chlorhexidine in a gel base; and G7, 2% CHX gel + 17% EDTA. After irrigation, Clearfil SE Bond was applied to pulp chamber dentin, followed by Filtek Z250 composite. Six rectangular sticks were obtained from each specimen and dentin/resin interface was tested in tension. Bond strength means were analyzed by ANOVA and Tukey test. There was a significant decrease in bond strength associated to NaOCl, whereas chlorhexidine irrigation showed no effects on adhesion. It was concluded that endodontic irrigants affected differently bond strength to pulp chamber dentin.

Endodontic status amongst 35-year-old Oslo citizens and changes over a 30-year period

AIM

To determine the prevalence of apical periodontitis and quality of root fillings in 35-year-old citizens of Oslo, Norway in 2003, and to compare the results with data from the same age cohort collected by repetitive cross-sectional studies in 1973, 1984 and 1993.

METHODOLOGY

A random sample of 250 35-year-old Oslo inhabitants was drawn from The National Bureau of Statistics Recordings. Attendance rate was 64%. Root filled teeth and teeth with periapical pathology were detected from panoramic radiographs and additional periapical radiographs of affected teeth were processed. The preriapical status was evaluated by applying the periapical index system (PAI). Chi-square and Student's t-tests were used for the evaluation of differences between the groups.

RESULTS

Twenty-three per cent of the individuals examined had root filled teeth and 16% had at least one tooth with apical periodontitis. Root filled teeth were associated with PAI values of 1 and 2 (health) in 57% of cases. Prevalence of root filled teeth and apical periodontitis remained unchanged during the past 10 years. An increase in the proportion of root filled teeth with apical periodontitis from 18% in 1973 to 43% in 2003 was observed.

CONCLUSIONS

Despite continuous improvement in dental health (reduced DMF-values) compared with the previous Oslo studies; there was no improvement in endodontic status from 1993 to 2003.

Endodontic Treatment Outcome: Survey of Oral Health Care Professionals

This study assessed the opinion of oral health care professionals regarding the predictability of initial endodontic treatment, expected long-term outcome and the importance of placing a coronal coverage after completion of treatment. An eight-item questionnaire was distributed among oral health care professionals. There were 49% of participants who responded that the expected retention rate of teeth 5 to 10 yr after endodontic treatment was more than 90%, whereas 44% responded that such retention rate was between 70 to 80%. The majority of the participants also responded that the need for additional treatment, such as retreatment, apical surgery or extraction, was expected to occur within the first 3 yr after endodontic treatment if initial treatment has failed. About 87% of participants responded that placing coronal coverage after completion of endodontic treatment in premolars and molars was very important for long-term tooth retention and 92% responded that overall, endodontic treatment was a predictable procedure with long-term tooth retention rate. Statistically significant associations were found between years of experience and expected rate of retention for both the total group of respondents (p < 0.001) and for general practitioners when examined separately (p < 0.002). Statistically significant associations were only found for general practitioners between years of experience and their responses regarding the need for additional treatment (p < 0.05) and overall predictability of endodontic treatment (p < 0.02). A trend was found between the professionals' years of experience and their opinion regarding the importance of coronal coverage. Of the group who had more than 20 yr of experience, about 87% considered coronal coverage to be very important for long-term tooth retention. In conclusion, it appears that most clinicians participating in this study consider endodontic therapy to be a predictable procedure with long-term tooth retention rate. Their opinions also reflect the variations that currently exist in the literature regarding the reported outcome of endodontic treatment.

Microleakage evaluation of intraorifice sealing materials in endodontically treated teeth

OBJECTIVE

Evaluate intraorifice sealing materials Cavit, Vitremer, and Flow-It for the prevention of coronal microleakage in root-canal treatment.

STUDY DESIGN

Root-canal treatment was performed on 80 extracted human molars. Three millimeters of coronal gutta-percha was removed from the coronal aspect of the root canal and replaced with one of the 3 filling materials. After thermocycling (5 degrees C to 55 degrees C) and 5 days of immersion in dye, the teeth were cleared for stereomicroscope evaluation for evidence of dye penetration into the sealing material and along canal walls.

RESULTS

All groups showed dye penetration into the root canal. Cavit sealed significantly better than the other groups (P < .01), preventing the coronal leakage in 90% of the specimens. Flow-It exhibited the highest leakage (65% of specimens) and did not differ significantly from the Vitremer group, which showed dye penetration in 55% of specimens.

CONCLUSION

Cavit sealed significantly better than Vitremer and Flow-It when used as intraorifice filling materials.

The relation between apical periodontitis and root-filled teeth in patients with periodontal treatment need

AIM

To investigate a number of clinical and treatment variables that might have influenced the prevalence of apical periodontitis in root-filled teeth in a population of periodontally compromised patients.

METHODOLOGY

This investigation was a retrospective cross-sectional study on data collected from periodontal charts in addition to intra-oral full-mouth radiographs from patients attending the Department of Periodontology of the Dental School of the Ghent University Hospital. Periodontal parameters (clinical attachment loss and the lowest marginal bone level, the history of periodontal treatment), endodontic treatment (length, homogeneity and overall quality of the root filling) and the quality of coronal restorations were related to the prevalence of apical periodontitis. A total of 272 root-filled teeth in 94 patients were evaluated.

RESULTS

The periapical condition was significantly influenced by the quality of the root filling and the coronal filling (P < 0.05). More apical periodontitis was seen when the coronal level of the root filling exceeded the marginal bone level (P < 0.005). The marginal periodontal condition seemed to influence the periapical status. Teeth with apical periodontitis were associated with significantly more extended marginal bone loss (P < 0.001). Significantly less apical periodontitis was seen in patients that had received marginal periodontal treatment (P < 0.005), compared with untreated periodontal patients.

CONCLUSIONS

Signs of periodontal disease, as reflected by marginal bone loss, are of importance for the periapical condition of root-filled teeth. Efforts should be taken in preventing spread of infection through the periodontal-endodontic pathway by periodontal infection control and a high quality of root filling and coronal filling. Care should also be taken to seal the coronal cavity up to the level of the root filling, where it is advisable to reduce the coronal level of the root filling below or at least at the level of the surrounding marginal bone.

Technical quality of root canal treatment and detection of iatrogenic errors in an undergraduate dental clinic

AIM

To evaluate the technical quality of root canal treatment (RCT) and detect iatrogenic errors in an undergraduate dental clinic.

METHODOLOGY

Three-hundred and eighty-eight root-filled teeth from the records of the Department of Endodontology at the Aristotle University of Thessaloniki, Greece were evaluated. Evaluation of root-filled teeth was based on two variables: length and presence of voids within the root filling. The technical standard of root fillings was categorized as: < or = 2 mm from the apex with no voids (acceptable); >2 mm from the apex with no voids; overfilling with no voids; < or = 2 mm from the apex with voids; >2 mm from the apex with voids and overfilling with voids. Iatrogenic errors that were detected included ledges, root perforations, furcation perforations, strip perforations and presence of fractured instruments. Chi-squared analysis was used to determine statistically significant differences between frequencies of root fillings between each tooth type. Significant differences were also determined between frequencies of ledges and root perforations according to tooth type and separately in molars according to tooth number, canal location and root canal curvature. Results Three-hundred and forty-three out of 620 root canals (55.3%) had a root filling that was classified as 'acceptable'. The frequency of root canals with an 'acceptable' filling was significantly greater in the anterior teeth (72.1%) than in pre-molars (55.2%) (P < 005) or in molars (46.7%) (P < 0.001). One-hundred and fifty-four (24.8%) root canals had ledges and 17 (2.7%) had a root perforation. The frequency of ledged root canals was significantly greater (P < 0.001) in molars than in anterior teeth. In molars, 105 out of 270 root canals (38.9%) had been ledged. Mesiobuccal, mesiolingual and distobuccal root canals were the most frequently ledged. Canal curvature was found to be the most important factor associated with ledges and root perforations. Conclusions Technical quality was found to be acceptable more often in anterior teeth. Ledges were identified more often in curved canals in molar teeth.

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.

Periradicular status related to the quality of coronal restorations and root canal fillings in a Brazilian population

OBJECTIVE

This cross-sectional study was undertaken to determine the prevalence of periradicular lesions in root-filled teeth from an urban adult Brazilian population, and to investigate the quality of root canal fillings and coronal restorations and their association with the periradicular status of these teeth.

STUDY DESIGN

Root canal fillings from 2,051 teeth were categorized as adequate or inadequate on the basis of root canal filling length and homogeneity. Coronal restorations from the same teeth were categorized into adequate, inadequate, or absent. Results were analyzed statistically using the chi-squared test.

RESULTS

The overall success rate of root-filled teeth was 49.7%. Cases with adequate endodontic treatment and adequate restorations had a success rate of 71%. When cases with adequate treatment and inadequate restoration were evaluated, the success rate was 65%. Cases with adequate treatment and absent restoration showed a success rate of 48%. Teeth with inadequate treatment combined with adequate restoration yielded a success rate of 38%, whereas the combination of inadequate treatment and inadequate restoration resulted in a success rate of 25%. Teeth with inadequate treatment and absent restoration showed the lowest success rate of this study (18%). Data analysis revealed that when the root canal filling appeared to be adequate, the quality of the restoration did not significantly influence the treatment outcome. However, when a coronal restoration was absent, the success rate of adequately treated canals was significantly reduced. The quality of the coronal restoration significantly affected the outcome of inadequately treated teeth.

CONCLUSIONS

Our results revealed a high prevalence of periradicular lesions in root-filled teeth, which was comparable to that reported in other methodologically compatible studies from diverse geographical locations. In addition, even though the coronal restoration had a significant impact on the periradicular health, the quality of the root canal filling was found to be the most critical factor in this regard.

The Effect of Thermocycling on a Colored Glass Ionomer Intracoronal Barrier

The purpose of this study was to evaluate the effect of thermocycling on a colored glass ionomer intracoronal barrier used for the prevention of microleakage. Thirty single canal premolars were decoronated, standardized in length, instrumented, obturated, and randomly assigned to three groups. Group 1 received a 1 mm intracoronal barrier of Triage glass ionomer, group 2 received a 2 mm Triage barrier, and group 3 received no barrier. After incubation for sealer set, teeth were thermocycled. Microleakage was measured using the fluid transport model. Groups 1, 2, and 3 demonstrated 1.68 mm, 0.60 mm, and 23.24 mm of movement, respectively. Using ANOVA and Student-Neumann-Keuls, group 3 leaked significantly more (p < 0.05) than groups 1 and 2, with no difference between groups 1 and 2. A 1 or 2 mm intracoronal barrier of Triage significantly reduced coronal microleakage in thermocycled endodontically treated teeth.

Prevalence of apical periodontitis and the quality of endodontic treatment in an adult Belarusian population

AIM

To estimate the prevalence of teeth with apical periodontitis (AP) and technically failed root fillings in an adult Belarusian population.

METHODOLOGY

Panoramic radiographs of all 1423 patients over 15 years of age not seeking emergency dental care, and attending the Dental School of the Belarusian Medical University for the first time during the period from 1 January to 31 December 2001 were examined. The quality of root fillings was scored according to criteria of length proposed by De Moor et al. [International Endodontic Journal 33 (2000) 113] and the periapical status of all teeth (except third molars) was categorized on the basis of presence or absence of radiographic signs of AP. The data were analysed using the chi-square test and odds ratio.

RESULTS

Radiographs indicated that 8632 teeth (22% in the maxilla; 21% in the mandible) were missing leaving a total of 31,212 teeth to be assessed. Twenty per cent of the teeth had some filling material in the root canal(s). AP was found in 1141 subjects (80%) and 12% of the teeth. AP was more frequently associated with molar teeth (23%) than premolar (14%), canine (4%) and incisor teeth (6%). AP was diagnosed in 45% of root filled teeth, the remaining cases with AP had not been root filled. Statistical analysis showed that the probability of radiological detection of AP in root filled teeth was 25-fold higher than when the root canals had not been filled (chi2 = 8636.04, P < or = 0.001, odds ratio with 95% confidence intervals: 23.01 < 25.17 < 27.45). Periapical radiolucencies with adequately filled root canals occurred significantly less often than with teeth in which the root canal was filled more than 2 mm from radiographic apex or when filling material was extruded through the apex.

CONCLUSION

The prevalence of AP in all age groups in Belarus was higher than in other populations. The probability of AP increased significantly after root canal treatment and was closely correlated with the quality of the root filling.

Adhesive Dentistry and Endodontics: Materials, Clinical Strategies and Procedures for Restoration of Access Cavities: A Review

The complexity of restorative dentistry has increased greatly in recent years, with the myriad of products used in "adhesive dentistry." So too has the "simple" matter of restoring access cavities after completion of endodontic treatment. This review discusses current methods of "bonding" to tooth structure, ceramic materials, and metals, with emphasis on those aspects that are important to endodontics. Specific materials, procedures and major decision making elements are discussed, as well as how to avoid problems in compatibility between endodontic and restorative materials.

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.

Cultivable microbial flora associated with persistent periapical disease and coronal leakage after root canal treatment: a preliminary study

AIM

To identify the cultivable bacterial flora in root filled teeth with persistent periapical lesions and to locate their distribution within the root canal system using an in vitro sampling protocol.

METHODOLOGY

Eight freshly extracted root filled teeth were collected from the Oral and Maxillo-facial Surgery Department, Eastman Dental Hospital. Seven teeth were associated with persistent apical periodontitis and also showed evidence of coronal leakage. Teeth were transferred to an anaerobic chamber immediately after careful extraction and sectioned transversely to give a crown (in all but one case) and two root segments (coronal and apical). Two samples were obtained from each segment, one from dentine and the other from the restoration or gutta-percha (GP) root filling (46 sites in total). The samples were dispersed, serially diluted and cultured on blood agar and fastidious anaerobic agar (with 5% defibrinated horse blood). The primary growth was subcultured to obtain pure isolates, which were identified by routine microbiological techniques and commercial enzyme tests.

RESULTS

A total of 252 strains were isolated from all the teeth. Of all the isolates, the most prevalent bacteria were Gram-positive facultative anaerobes 189/252 (75%) with staphylococci (48/252, 19%), streptococci (44/252, 17%), enterococci (20/252, 8%) and Actinomyces species (20/252, 8%) being found in most of the teeth (6/8, 6/8, 5/8, 5/8 and 7/8, respectively). Of the obligate anaerobes (17%), peptostreptococci (7%) were also present in most teeth (7/8). A statistical association between bacterial flora and site (crown/coronal/apical) or surface (dental/GP/restoration) could not be shown.

CONCLUSIONS

The predominant group of bacteria in root filled teeth with persistent apical periodontitis and coronal leakage was Gram-positive facultative anaerobes of which staphylococci followed by streptococci and enterococci were the most prevalent.

Increased width of the apical periodontal membrane space in endodontically treated teeth may represent favourable healing

AIM

To examine cases showing increased width of the periodontal space (IW) at a long-term follow-up examination and to determine whether this finding could be explained by endodontic or nonendodontic factors.

METHODOLOGY

A series of intraoral radiographs was obtained from 131 patients 20-27 years after root canal treatment. The same individuals had been examined 10 years earlier, and radiographs taken immediately after treatment were also available. Fourteen roots (5.6%) demonstrated increased width of the apical periodontal space at the end of the study period. These were subjected to further analysis in an attempt to disclose possible explanatory factors.

RESULTS

Two of the 14 cases had reduced marginal bone levels interpreted as the origin of the IW. In three cases, overextended root filling material present 10 years earlier had disappeared and the persistent IW was interpreted as representing a remodelling process. In six cases the findings were explained as being caused by physical and anatomical factors that represented healing without complete re-formation of the apical periodontal structures, or both. Three cases were judged as unfavourable, on the basis of lacking progress in healing, unsatisfactory obturation of the apical portion of the root canal or dentine resorption close to the apical end of the root filling.

CONCLUSION

Most of the 14 IW cases examined after 20-27 years could be explained by reduced marginal bone support, or by physical and anatomical factors or they might represent incomplete reformation of the typical apical morphology and were thereby recorded as favourable outcomes.

Post placement and restoration of endodontically treated teeth: a literature review

The restoration of endodontically treated teeth is a topic that is extensively studied and yet remains controversial from many perspectives. This article reviews the major pertinent literature on this topic, with an emphasis on major decision-making elements in post placement and restoration of endodontically treated teeth. Recommendations are made for treatment planning, materials, and clinical practices from restorative and endodontic perspectives.

Anin vitrocomparison of adhesive systems to seal pulp chamber walls

AIM

To compare in vitro the sealing properties of five different dentine adhesive materials (Prime&Bond NT (PBNT); Prompt L-Pop (PLP); Clearfil SE Bond (CSEB); Scotchbond Multi Purpose Plus (SMPP); EBS-Multi (EBSM)) inside the pulp chamber.

METHODOLOGY

Seventy-five recently extracted human molar teeth were used. The roof of the pulp chambers and roots were removed under water cooling. Pulp tissue was removed, and the canal orifices were sealed. The pulp chambers were then treated with 5% sodium hypochlorite (NaOCl) for 1 min. The teeth were randomly divided into five groups of 15 teeth each. Adhesive systems were applied to the pulp chamber walls according to the manufacturers' instructions. The samples were connected to Plexiglass plates, and a fluid filtration method was used for quantitative evaluation of leakage. Measurements of fluid movement were made at 2-min intervals for 8 min. The quality of seal of each specimen was measured immediately, after 24 h, 1 week and 1 month. The data were statistically analysed by repeated-measurements multivariate anova, Friedman test, Wilcoxon signed rank test, Kruskal-Wallis of one-way anova and Mann-Whitney U-tests. The pulp chamber wall with and without NaOCl and resin-dentine interfaces of specimens were observed under a scanning electron microscope (SEM).

RESULTS

The leakage values of the materials were significantly different at different measurement periods. In all groups, leakage values decreased with time (P < 0.05). PBNT and PLP had the least leakage during immediate measurements (P < 0.05). After 1 month, leakage of all adhesive systems was not significantly different (P < 0.05). SEM observation of pulp chamber walls demonstrated that the irregular dentine surface without smear layer was present in the nontreated group. However, NaOCl application removed the collagen fibrils leaving the dentine surface smooth. At resin-dentine interfaces of specimens, no hybridization zone was observed.

CONCLUSIONS

None of the materials had created a perfect seal to the pulp chamber walls. PBNT and PLP had better sealing over the short term, but over the long term, there were no differences between the materials.

The use of glass ionomer cements in both conventional and surgical endodontics

The capacity to bond to dental tissues, especially to dentine, their long-term fluoride release and their biocompatibility make glass ionomer cements (GICs) advantageous for use in endodontics, as well as in restorative dentistry. This review provides information on the basic properties of GICs, such as adhesion, antimicrobial effects and biocompatibility, particularly as they relate to use in endodontics. Indications for the use of GICs in endodontics are orthograde root canal sealing, root-end filling, repair of perforations and root resorption defects, treatment of vertical fractures and maintenance of the coronal seal. The paper includes a review on each of these indications. It is concluded that in spite of the critical handling characteristics and the inconclusive findings regarding sealing ability and antimicrobial activity, there is substantial evidence to confirm their satisfactory clinical performance. Both soft tissue and bone compatibility make them suitable for use during endodontic surgery.

Relationship of Radiologic and Histologic Signs of Inflammation in Human Root-filled Teeth

The aim of this study was to determine the relationship between histologic and radiologic signs of inflammation in human root-filled teeth. In addition, other factors with possible importance for apical inflammation were assessed. Fifty-three block sections of root-filled teeth were gathered from human cadavers. The blocks were radiographically exposed, sectioned, and stained with hematoxylin and eosin. Histologic sections were categorized as inflamed or uninflamed. Radiographically, the roots were assigned as apical lucency, widened periodontal ligament (PDL), or no lucency. Presence and contents of accessory canals were recorded (empty, tissue, or filling material). Statistical analysis was performed with the Chi-square test. All roots had accessory canals; 12 showed tissue remnants, and the others were empty. Of the cases, 49% were histologically uninflamed at the apex, and 52% appeared radiographically intact. The odds ratio of finding a histologically inflamed apex with radiologic lucency versus a radiographically intact apex was 9.2 (p = 0.002). The odds ratio of finding a histologically uninflamed apex with a radiologically tight coronal seal versus an unacceptable seal was 3.7 (p = 0.053). It may be concluded that there are relationships between radiologic and histologic signs of inflammation in human root canal-treated teeth. There appears to be a tendency that the radiologically determined quality of the coronal seal has an impact on the histologic state of the root-filled tooth. No relationship was detected between unfilled lateral or accessory canals and the status of inflammation at the periapex (51% inflamed, 49% uninflamed).

Bacterial status in root-filled teeth exposed to the oral environment by loss of restoration and fracture or caries - a histobacteriological study of treated cases

AIM

To describe histological and microbiological findings in teeth where root fillings had been exposed to caries and the oral environment for a prolonged period.

METHODOLOGY

For inclusion in the study, only teeth with a follow-up period of 3 years or more and those that had been without proper restoration for at least a period of 3 months were considered. Some root fillings had been without restoration for several years. In all, 39 roots representing 32 teeth were examined by histology.

RESULTS

The majority of the specimens were without a discernible periapical bone lesion as assessed by radiography. Osteolytic lesions were seen with five roots. Longitudinal tissue sections stained with a modified Brown/Brenn staining technique revealed presence of stainable bacteria in abundance at the canal entrance and in dentinal tubules but were absent mid-root and apically in all but two specimens. Soft tissue attached to the root tip and in apical ramifications displayed distinct inflammatory cell infiltrates, suggesting microbial exposure in 7 of the 39 roots examined. In all other specimens, inflammatory cell infiltrates were either nonexistent or sparse and then associated with extruded sealer material.

CONCLUSIONS

Well-prepared and filled root canals resist bacterial penetration even upon frank and long-standing oral exposure by caries, fracture or loss of restoration.

Root canal treatment performed by Flemish dentists. Part 1. Cleaning and shaping

AIM

To gather information on root canal treatment carried out by dentists working in Flanders (Belgium).

METHODOLOGY

A questionnaire was handed to 312 dentists attending peer review sessions organized by the Flemish Universities. Basic information (age, gender, year of graduation, practice profile) and information on various issues relating to the cleaning and shaping of root canals was collected.

RESULTS

A total of 310 questionnaires were returned. The majority (85.7%) of respondents categorized themselves as general practitioners; 25.7% mentioned a clinical interest or speciality in practice. Most practitioners (64.5%) did not use rubber dam routinely during root canal treatment and performed treatment over two visits irrespective of the number of root canals. The majority of respondents (82.4%) used sodium hypochlorite as an irrigant, but 10.6% did not know the concentration they used; EDTA was used by 61.6%. The vast majority exposed a radiograph with an instrument of known length in situ to gauge the working length; only 3.6% relied on tactile sense; electronic root canal length determination was seldom used. Amongst the root canal instruments, K-files were used solely or in combination with other instruments by 60.3% of the respondents, reamers were used solely or in combination with other instruments by 55.4%. The stepback technique was used by 31.2% of the participants, a combination of stepdown and stepback by 26.4%, a reaming technique by 26.1% and the step-down technique by 14.7%. The majority were familiar with mechanical root canal Instruments. Almost half of the practitioners believed their preparation technique could be improved: only 1.3% felt that their procedures were poor.

CONCLUSIONS

The results of this study indicate that the theoretical knowledge of dentists working in Flanders is good. However, the use of rubber dam remained low, half believed their preparation technique could be improved.