Assessment of the root and canal morphology in the permanent dentition of Saudi Arabian population using cone beam computed and micro-computed tomography - a systematic review

INTRODUCTION

Root canal treatment procedures require a thorough understanding of root and canal anatomy. The purpose of this systematic review was to examine the morphological differences of teeth root and their canals assessed using cone-beam computed and micro-computed tomography in Saudi Arabian population.

METHODOLOGY

An electronic search was conducted in PubMed / Medline, Scopus, Google Scholar, and Web of Science databases until January 2023 to retrieve related studies. "Root canal morphology," "Saudi Arabia," "Micro-CT," and "cone-beam computed tomography" were used as keywords. A modified version of previously published risk of bias assessment tool was used to determine the quality assessment of included studies.

RESULTS

The literature search revealed 47 studies that matched the criteria for inclusion, out of which 44 studies used cone beam computed tomography (CBCT) and three were micro-computed tomography (micro-CT) studies. According to the modified version of risk of bias assessment tool, the studies were categorized as low, moderate, and high risk of bias. A total of 47,612 samples were included which comprised of either maxillary teeth (5,412), or mandibular teeth (20,572), and mixed teeth (21,327). 265 samples were used in micro-CT studies while 47,347 teeth samples were used in CBCT studies. Among the CBCT studies, except for three, all the studies were retrospective studies. Frequently used imaging machine and software were 3D Accuitomo 170 and Morita's i-Dixel 3D imaging software respectively. Minimum and maximum voxel sizes were 75 and 300 μm, Vertucci's classification was mostly used to classify the root canal morphology of the teeth. The included micro-CT studies were in-vitro studies where SkyScan 1172 X-ray scanner was the imaging machine with pixel size ranging between 13.4 and 27.4 μm. Vertucci, Ahmed et al. and Pomeranz et al. classifications were applied to classify the root canal morphology.

CONCLUSION

This systematic review revealed wide variations in root and canal morphology of Saudi population using high resolution imaging techniques. Clinicians should be aware of the common and unusual root and canal anatomy before commencing root canal treatment. Future micro-CT studies are needed to provide additional qualitative and quantitative data presentations.

Evaluation of endodontically treated teeth and related apical periodontitis using periapical and endodontic status scale: Retrospective cone-beam computed tomography study

The purpose of this study was to evaluate the technical treatment quality and the status of apical pathology of endodontically treated teeth, as well as apical periodontitis (AP) prevalence, in a Turkish population using cone-beam computed tomography (CBCT). The CBCT images obtained between January 2018 and April 2020 were retrospectively examined. The quality of the endodontic treatments and the related periapical inflammatory lesions were classified according to the periapical and endodontic status scale (PESS). The data were statistically analysed using logistic regression, crosstabs and chi-square tests. AP was detected in 41% of 429 endodontically treated teeth. The prevalence of AP was significantly higher in teeth with inadequate root canal treatment compared with those with adequate treatment, 70.8% and 29.3%, respectively. Inadequate canal length and homogeneity, and complications were significantly associated with the prognostic periapical status scores of higher risk.

Effects of an individualized training course on technical quality and periapical status of teeth treated endodontically by dentists in the Public Dental Service in Norway: An observational intervention study

AIM

To investigate the effect of a continuing education course on technical quality and treatment outcome for root filled permanent teeth in Møre and Romsdal County, Norway.

METHODOLOGY

Fifty-two dentists employed in the Public Dental Service in Møre and Romsdal county, Norway, completed a two-day continuing education course in root canal treatment. Periapical radiographs of root filled teeth treated before and after the course, with at least one-year follow-up were identified and scored for technical quality and periapical status. Technical root filling quality was assessed by density and length and the treatment outcome by PAI scores. Treatment information was achieved from the county's electronic dental record system. Information regarding the dental practitioners' background and treatment procedure routines was collected by a questionnaire. Descriptive statistics analyses and mixed-effect logistic regression analyses were performed to evaluate the effect of the course.

RESULTS

Radiographs were available for 224 teeth root filled before and for 221 teeth after the course. The proportion of teeth with adequate root filling quality was significantly lower after the course (p = .006), associated mainly with short root fillings (p < .001). No significant differences were observed in treatment outcome. There were, however, large differences in treatment outcome amongst subgroups of dentists. Further, there was evidence of effect modification by the continuing education course on periapical outcome by patient's age (p_interaction  = .0023) suggesting that teeth in patients ≤18 years healed relatively better post-course compared to patients >18 years.

CONCLUSIONS

A two-day continuing education course in root canal treatment attended by Public Dental Service dentists in Norway did not improve the technical quality of root fillings or periapical status associated with root filled teeth.

Health status in patients hospitalised for severe odontogenic infections

OBJECTIVE

Previous findings refer to certain predisposing medical conditions that compound the risk of developing severe and potentially lethal acute odontogenic infections (OI). The objective of this study was to clarify this rationale and infection severity in general.

MATERIAL AND METHODS

Records of patients aged ≥18 years requiring hospital care for deep OI were retrospectively investigated. The main outcome variable was need for intensive care unit (ICU) treatment. Additional outcome variable was occurrence of infection complications and/or distant infections. Several parameters describing patients' prior health and recent dental treatment were set as independent variables.

RESULTS

Of the 303 acute OI patients included, 71 patients (23%) required treatment in the ICU, with no significant difference between previously healthy and patients with disease history. OIs originating from teeth in the mandible compared with maxilla had 7.8-fold risk (p = .007) for ICU treatment in binary logistic regression analyses. Elevated levels of infection parameters at hospital admission predicted further ICU stay. Infection complications and/or distant infections occurred in 7.6% of patients, of which septicaemia and pneumonia were the most common. The mortality rate was 0.3%. Infection complications and/or distant infections occurred significantly more often in smokers (p = .001) and in patients with excessive consumption of alcohol or drugs (p = .025), however smoking showed 3.5-folded independent risk for infection complications and/or distant infections (p = .008) in logistic regression.

CONCLUSIONS

Severe OIs often occur in previously healthy patients. Smokers in particular are prone to the most serious OIs.

Effects of an individualised training course in endodontics on the knowledge and insights of dentists in Public Dental Service in Norway

OBJECTIVE

To evaluate the knowledge and insights of general dental practitioners regarding endodontic diagnosis and treatment principles before and after attending a 2-days continuing education course.

MATERIALS AND METHODS

Sixty-seven dentists employed in the Public Dental Service in Møre and Romsdal county, Norway, were invited to a continuing education course in endodontics. Before and after the course, they answered a questionnaire weighing the importance of factors influencing the prognosis of endodontic treatment. The same questionnaire was answered by specialists in endodontics (n = 56; Spec Group) and a reference group consisting of general dental practitioners from both private and public practice (n = 21; Ref Group). The Test Group answered both before and after the course, while the Spec and Ref Groups completed the questionnaire once. The responses were compared using the Wilcoxon Sign test and Mann-Whitey U test.

RESULTS

Of the 67 dentists in the Test Group, 49 (73%) completed the course and answered both questionnaires. Before attending the course, the Test Group differed significantly from the Spec Group in 18 out of 27 prognostic factors (p ≤ .05). After the course, there was only moderate improvement in the Test Group responses. On only three factors, they agreed significantly more with the specialists than before attending the course (p ≤ .05). After the Test Group participants had attended the course, their responses were comparable to the responses of the Ref Group.

CONCLUSIONS

A two-days continuing education course only marginally improved dentists' level of knowledge and insights regarding the influence of prognostic factors in endodontics.

YouTube as an information source for instrument separation in root canal treatment

Objectives

The reliability and educational quality of videos on YouTube for patients seeking information regarding instrument separation in root canal treatment were evaluated.

Materials and Methods

YouTube was searched for videos on instrument separation in root canal treatment. Video content was scored based on reliability in terms of 3 categories (etiology, procedure, and prognosis) and based on video flow, quality, and educational usefulness using the Global Quality Score (GQS). Descriptive statistics were obtained and the data were analyzed using analysis of variance and the Kruskal-Wallis test.

Results

The highest mean completeness scores were obtained for videos published by dentists or specialists (1.48 ± 1.06). There was no statistically significant difference among sources of upload in terms of content completeness. The highest mean GQS was found for videos published by dentists or specialists (1.82 ± 0.96), although there was no statistically significant correlation between GQS and the source of upload.

Conclusions

Videos on YouTube have incomplete and low-quality content for patients who are concerned about instrument separation during endodontic treatment, or who experience this complication during endodontic treatment.

Radiographic outcome of root canal treatment in general dental practice: tooth type and quality of root filling as prognostic factors

OBJECTIVE

This study evaluated the radiographic outcome of root canal treatments (RCTs) performed by general dental practitioners (GDPs) with focus on tooth type and quality of root filling.

MATERIALS AND METHODS

The target population included all patients receiving root filling by GDPs in City of Helsinki in 2010-2011. Equal numbers of each tooth type (anteriors, premolars, molars) by jaw were included, resulting in 426 teeth. Pre- and post-operative periapical radiographs were assessed to evaluate periapical status and quality of root filling. Statistical evaluation utilized Chi-squared tests, Cohen's kappa and logistic regression modelling.

RESULTS

The overall success rate of RCT was 67.4%, being 76.8%, 69.7% and 55.6% (p < .001) for anteriors, premolars and molars, respectively. The quality of root fillings varied by tooth type (p < .001); optimal fillings were least frequent (43%) in molars. In multifactorial analysis, RCTs were more likely to succeed in non-molars (OR = 1.8), in teeth with optimal root fillings (OR = 3.6) and in teeth without apical periodontitis (OR = 3.2).

CONCLUSION

The quality of root fillings and radiographic outcome of RCTs varied considerably according to tooth type; success was least likely in molars. Improvement is needed in quality of RCTs by GDPs.

Controversies in Endodontics

Diseases of the dental pulp often have an infectious origin, and treatments are aimed to control infections of the root canal system. Endodontic treatment principles originally evolved on the basis of trial and error, and only in recent decades have scientific methods been adopted to support clinical strategies. Yet, relevant research on the disease processes, their diagnoses, and efficient treatment are rare in the endodontic literature. Hence, the advancement of biologically based knowledge significant to clinical endodontics has been slow. Therefore, many differences of opinion still prevail in this field of dentistry. This review highlights and analyzes the background of some of the more heavily debated issues in recent years. Specifically, it deals with disagreements regarding the clinical management of pulpal exposures by caries in the adult dentition, definitions of success and failure of endodontic therapy, and causes of and measures to control infections of the root canal system. Clearly, a most apparent gap in the published endodontic literature is the lack of randomized clinical trials that address the more significant controversial matters relating to the management of pulpal wounds, medication, and the number of appointments required for the treatment of infected root canals. However, trials in endodontics require extremely long follow-up periods if valid conclusions are to be generated. Therefore, it is not to be expected that there will be rapid solutions to these issues in the foreseeable future.

Apical periodontitis and the technical quality of root canal treatment in an adult sub-population in London

AIM

To assess the prevalence of apical periodontitis (AP) and the technical quality of root canal treatment in an adult sub-population in London.

METHODOLOGY

Panoramic radiographs of 136 patients who attended a dental hospital were collected. The periapical health of teeth present was assessed radiographically and the presence or absence of AP noted. The technical quality of the root canal treatment was scored as adequate or inadequate, based on the European Society of Endodontology (2006) guidelines.

RESULTS

A total of 3,396 teeth were assessed; AP was detected in 4.1% of the teeth. Forty-nine percent of patients had at least one tooth with radiographic evidence of AP. The percentage of root filled teeth with AP was 38.3%. AP was significantly more frequently found in root treated, compared with non-root treated, teeth (p <0.001). In 44.3% of the cases, the technical quality of the root canal filling was inadequate. AP was detected in 14% of adequately, compared with 68.6% of inadequately, root filled teeth. There is a significant negative correlation between the technical quality of root canal treatment and the presence of AP (p <0.001).

CONCLUSIONS

There was a high prevalence of AP and poor technical quality root canal treatment; a strong association between AP and root filled teeth, and between the periapical health and the technical quality of the root canal treatment. The results are consistent with previous studies using similar methodology and re-confirmed that high technical quality root canal treatment is crucial to ensure a favourable treatment outcome.

Effect of education intervention on the quality and long-term outcomes of root canal treatment in general practice

AIM

To compare the technical quality and long-term outcomes of root canal treatment by general practitioners of a Swedish Public Dental Service, before and after an endodontic education including Ni-Ti rotary technique (NiTiR).

METHODOLOGY

A random sample was compiled, comprising one root filled tooth from each of 830 patients, treated by 69 general practitioners participating in the education: 414 teeth root filled in 2002, pre-education, using primarily stainless steel instrumentation and filling by lateral compaction, and 416 teeth root filled post-education (2005), using mainly NiTiR and single-cone obturation. Follow-up radiographs taken in 2009 were evaluated alongside immediate post-filling radiographs from 2002 to 2005. The density and length of the root fillings were registered. Periapical status was assessed by the Periapical Index (PAI), using two definitions of disease: apical periodontitis (AP) (PAI 3 + 4 + 5) and definite AP (PAI 4 + 5). Tooth survival was registered. Root fillings pre- and post-education were compared using chi-square and Fisher's exact tests. Crude extraction rates per 100 years were calculated for comparison of tooth survival. Explanatory variables (type of tooth, root filling quality, periapical status, marginal bone loss, type and quality of coronal restoration) in relation to the dependent variable (AP at follow-up) were analysed by multivariable logistic regression.

RESULTS

Follow-up data were available for 229 (55%) of teeth treated pre- and 288 (69%) treated post-education: both tooth survival (P < 0.001) and root filling quality were significantly higher (P < 0.001) in the latter. However, there was no corresponding improvement in periapical status. Both pre- and post-education, root fillings with definite AP on completion of treatment had significantly higher odds of AP or definite AP at follow-up. For teeth treated post-education, inadequate root filling quality was significantly associated with AP at follow-up.

CONCLUSIONS

Despite a higher tooth survival rate and a significant improvement in technical quality of root fillings after the education, there was no corresponding improvement in periapical status.

Ability of new obturation materials to improve the seal of the root canal system: a review

New obturation biomaterials have been introduced over the past decade to improve the seal of the root canal system. However, it is not clear whether they have really produced a three-dimensional impervious seal that is important for reducing diseases associated with root canal treatment. A review of the literature was performed to identify models that have been employed for evaluating the seal of the root canal system. In vitro and in vivo models are not totally adept at quantifying the seal of root canals obturated with classic materials. Thus, one has to resort to clinical outcomes to examine whether there are real benefits associated with the use of recently introduced materials for obturating root canals. However, there is no simple answer because endodontic treatment outcomes are influenced by a host of other predictors that are more likely to take precedence over the influence of obturation materials. From the perspective of clinical performance, classic root filling materials have stood the test of time. Because many of the recently introduced materials are so new, there is not enough evidence yet to support their ability to improve clinical performance. This emphasizes the need to translate anecdotal information into clinically relevant research data on new biomaterials.

Quality of root fillings performed with two root filling techniques. An in vitro study using micro-CT

Objective.

The aim of this study was to compare the presence of voids in root fillings performed in oval and ribbon-shaped canals with two root filling techniques, lateral compaction technique (LCT) or hybrid technique (HT), a combination of a gutta-percha masterpoint and thermoplastic gutta-percha. Furthermore, the obturation time for the two techniques was evaluated.

Materials and methods.

Sixty-seven roots with oval and ribbon-shaped canals were prepared using Profile Ni-Ti rotary files. After preparation, the roots were randomly allocated to two groups according to root filling technique. All roots were filled with AH plus and gutta-percha. Group 1 was filled using LCT (n = 34) and group 2 was filled using HT (n = 33). The obturation time was measured in 30 cases evenly distributed between the two techniques. Voids in relation to the root canal fillings were assessed using cross-section images from Micro-computed Tomography scans.

Results.

All root canal fillings had voids. Permutation test showed no statistically significant difference between the two root filling techniques in relation to presence of voids (p = 0.092). A statistically significant difference in obturation time between the two techniques was found (p < 0.001).

Conclusion.

The present study found no statistically significant difference in percentage of voids between two root filling techniques. A 40% reduction in obturation time was found for the HT compared to the LCT.

The detection of periapical pathosis using digital periapical radiography and cone beam computed tomography - part 2: a 1-year post-treatment follow-up

AIM

Part 2 of this clinical study aims to compare the radiographic change in periapical status of individual roots determined using digital periapical radiographs versus cone beam computed tomography (CBCT) 1year after primary root canal treatment and to determine the radiological outcome of treatment for each tooth.

METHODOLOGY

Periapical radiographs and CBCT scans of 123 teeth in 99 patients assessed 1year after completion of primary root canal treatment by a single operator were compared with their respective pre-treatment (diagnostic) periapical radiographs and CBCT scans. The presence or absence as well as the increase or decrease in size of existing periapical radiolucency was assessed by a consensus panel consisting of two calibrated examiners. The panel viewed the images under standardized conditions. Paired comparison of the outcome diagnosis of individual roots and teeth was performed using generalized McNemar's or Stuart-Maxwell test of symmetry analysis.

RESULTS

The 'healed' rate (absence of periapical radiolucency) for all roots combined was 92.7% using periapical radiographs and 73.9% for CBCT (P<0.001). This rate increased to 97.2% and 89.4%, respectively, when the 'healing' group (reduced size of periapical radiolucency) was included (P<0.001). A statistically significant difference in outcome diagnosis of single roots was observed between DPA and CBCT in single-rooted teeth and the buccal or mesio-buccal roots of multi-rooted teeth (P<0.05). Analysis by tooth revealed that the 'healed' rate (absence of periapical radiolucency) was 87% using periapical radiographs and 62.5% using CBCT (P<0.001). This increased to 95.1% and 84.7%, respectively, when the 'healing' group (reduced size of periapical radiolucency) was included (P<0.002). Outcome diagnosis of teeth showed a statistically significant difference between systems (P<0.001). Reconstructed CBCT images revealed more failures (17.6%) in teeth with no pre-operative periapical radiolucencies compared with periapical radiographs (1.3%) (P=0.031). In teeth with existing pre-operative periapical radiolucencies, reconstructed CBCT images also showed more failures (13.9%) compared with periapical radiographs (10.4%).

CONCLUSION

Diagnosis using CBCT revealed a lower healed and healing rate for primary root canal treatment than periapical radiographs, particularly in roots of molars. There was a 14 times increase in failure rate when teeth with no pre-operative periapical radiolucencies were assessed with CBCT compared with periapical radiographs at 1year.

An investigation of current endodontic practice in Turkey

Objectives. The aim of this study was to gather information about the quality and quantity of root canal treatments carried out by general dental practitioners in Turkey. Methods. Questionnaires were given to 1400 dentists who attended the 16th National Congress organized by the Turkish Dental Association. The participants were asked to answer 34 multiple-choice questions. The questions were subdivided into 3 main topics; general information; general approach to endodontic treatment; and cleaning, shaping, and obturation of root canals. The statistical analysis was carried out by an χ²-test to compare the means at a significance level of P < 0.05. Results. The response rate for this study was 43%. There was a wide variation in the number of root canal treatments completed per month. Nearly 92% of practitioners stated that they never used rubber dam. The most commonly used working length determination technique was radiographic evaluation (P < 0.05). Sodium hypochlorite was the irrigant of choice with varying concentrations and AH Plus was the sealer of choice (P < 0.05). Resin composite was the most frequently used material for final restorations. Conclusions. Endodontic procedures in general practice in Turkey have differences from widely acknowledged quality guidelines. Despite the introduction of new instruments and techniques, most of the general practitioners chose conventional methods.

Prevalence of apical periodontitis and factors associated with the periradicular status

AIM

The present study aimed at assessing the prevalence of apical periodontitis and identifying the factors associated with apical periodontitis, particularly the influence of the quality of root canal fillings and coronal restorations on the periradicular status.

METHODOLOGY

The study population consisted of adult patients, men and women, seeking routine dental care at the Endodontic Clinic in the school teaching hospital between September 2006 and July 2008. For each patient complete oral examination and periapical radiographs were made for pathological teeth. All teeth were assessed individually. AP was diagnosed according to defined criteria, other variables were root fillings, coronal fillings, trauma and caries. The odds ratio and 95% confidence interval were used to calculate the risk of apical periodontitis related to tooth-specific risk indicators on the presence of apical periodontitis. A multiple logistic regression model to control for confounders and to determine their independent association with apical periodontitis was used also.

RESULTS

AP was detected on teeth (63.79%). The prevalence of apical periodontitis in root canal-treated teeth was 39.5%. Of the dental variables caries, trauma, inadequate root fillings and inadequate restoration were significantly associated with AP.

CONCLUSION

The prevalence of AP in this study group was higher than in other populations. The probability of AP increased significantly after root canal treatment and coronal filling and was closely associated with the quality of the filling.

Technique acquisition in the use of two thermoplasticized root filling methods by inexperienced dental students: a microcomputed tomography analysis

INTRODUCTION

Limited endodontic experiences in dental schools suggest the need for easy-to-learn techniques. Therefore, two simplified root filling methods were assessed for adequacy and expediency when performed by inexperienced students.

METHODS

Eight students were trained (45-minute lecture and 90-minute practice) in use of ProTaper Obturators (PTO) and System-B/Calamus (SBC). They subsequently filled the root canals in two extracted, single-rooted teeth per method (n = 32). Canals were preshaped and prefitted with obturators and master cones. The volume of root-filling voids determined by microcomputed tomography imaging in 1-mm increments, time to complete fillings, and students' responses in questionnaires were analyzed (independent-sample t test and Mann-Whitney U test).

RESULTS

PTO had a significantly smaller void volume in the apical 6 mm of canals (P < 0.001), required significantly shorter time (P < 0.001), and was perceived as easier to learn and use but less likely to be favored after graduation than SBC.

CONCLUSION

These results suggested that the PTO root filling method was particularly suitable for teaching when endodontic experiences available for students are limited.

The technical quality of nonsurgical root canal treatment performed by a selected cohort of Australian endodontists

AIM

To investigate the technical quality of nonsurgical root canal treatment performed by endodontists in Melbourne, Australia.

METHODOLOGY

Clinical and radiographic records of 100 sequential nonsurgical patients were obtained from each of six endodontists working in private practice. The following variables were analysed: proximity of root filling to radiographic apex; homogeneity and radiodensity of root filling; lateral adaptation of the root filling to the canal walls; taper; extrusion of material; small, appropriate or excessive apical enlargement; presence of lateral canals; transportation; procedural errors. The radiographs were assessed by three independent evaluators. Exploratory data analysis was undertaken using simple frequencies and cross-tabulations. A generalised linear mixed model (GLMM) was used for the formal statistical modelling.

RESULTS

Of the 1351 canals that were examined, 91.7% were filled within 2 mm of the radiographic apex and 74% were within 1 mm. Homogeneity and adequate density were found along the entire length of the canal in 86.1% and 88.6% of cases respectively. Lateral adaptation was adequate in 95.6% of cases and the taper was 'smooth and continuous' in 83.8% of roots. No and/or small extrusion of sealer was noted in 98.3% of cases. Apical enlargement was 'appropriate' in 85% of roots. Both transportation (1.1%) and procedural errors (1.3%) were rare occurrences.

CONCLUSIONS

The technical quality of root fillings performed by endodontists in Melbourne, Australia complied with current guidelines in 77.4%-91.0% of roots. All variables examined confirmed high levels of technical proficiency. There were very few instances of canal transportation and/or procedural errors.

Quality of Molar Root Canal Fillings Performed With the Lateral Compaction and the Single-Cone Technique

The aim was to compare the quality of root canal fillings performed with the single-cone and lateral compaction technique. Thirty-six canals in extracted molars were filled with ISO-standardized gutta-percha points, .02 taper, by using the lateral compaction technique; 38 were filled with one gutta-percha point, .04 taper, by using the single-cone technique. Each root canal was radiographed in the bucco-oral (BO) and the mesiodistal projection (MD). A root was sufficiently filled when three of four observers had assessed it so. There was no significant impact of the filling technique on the quality (logistic regression analysis, p > 0.4). There was a significant impact of the canal type, the mandibular distal canal having a higher chance for a sufficient root filling than the mandibular mesial canal in projection BO (p = .003), but both the mandibular distal (p = 0.001) and the maxillary palatal canals (p = 0.014) had a lower chance for a sufficient filling in projection MD.

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.

Rotary NiTi Instrument Fracture and its Consequences

The fracture of endodontic instruments is a procedural problem creating a major obstacle to normally routine therapy. With the advent of rotary nickel-titanium (NiTi) instruments this issue seems to have assumed such prominence as to be a considerable hindrance to the adoption of this major technical advancement. Considerable research has been undertaken to understand the mechanisms of failure of NiTi alloy to minimize its occurrence. This has led to changes in instrument design, instrumentation protocols, and manufacturing methods. In addition, factors related to clinician experience, technique, and competence have been shown to be influential. From an assessment of the literature presented, we derive clinical recommendations concerning prevention and management of this complication.

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.

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.

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.

An analysis of endodontic treatment with three nickel-titanium rotary root canal preparation techniques

AIM

To investigate clinical results of root canal treatment performed with the aid of nickel-titanium (NiTi) rotary instruments.

SUMMARY

A total of 179 patients underwent root canal treatment with either (A) Lightspeed, or (B) ProFile .04 or (C) ProFile .04 and .06 or GT rotary instruments to create tapered preparations. In groups A and B, laterally condensed gutta-percha and AH Plus were used. Canals in group C were obturated with System B, Obtura II and Roth's 801 sealer. Initial and recall radiographs were assessed using the periapical index (PAI). Outcomes were analysed using chi-square tests, event-time analyses and logistic regression models. Two hundred and thirty-three teeth were radiographically assessed after a mean interval of 25.4 +/- 11.8 months. Favourable outcome of treatment, defined as PAI < 3 at recall was 86.7%. Logistic regression analysis and univariate analyses indicated that teeth with preoperative PAI scores >2 and retreated teeth had a significantly lower chance of healing compared with periapically healthy teeth and primary treatments, respectively. Preparation technique, length of fill and the type of sealer did not significantly affect healing rates.

KEY LEARNING POINTS

Root canal treatment with NiTi root canal instrumentation systems renders favourable outcomes in more than 86% of the cases. Outcome is significantly affected by preoperative diagnoses but not by the specific choice of instrumentation system.

Current Challenges and Concepts in the Preparation of Root Canal Systems: A Review

Nickel-titanium rotary instruments are important adjuncts in endodontic therapy. This review attempts to identify factors that influence shaping outcomes with these files, such as preoperative root-canal anatomy and instrument tip design. Other, less significant factors include operator experience, rotational speed, and specific instrument sequence. Implications of various working length definitions and desired apical widths are correlated with clinical results. Despite the existence of one ever-present risk factor, dental anatomy, shaping outcomes with nickel-titanium rotary instruments are mostly predictable. Current evidence indicates that wider apical preparations are feasible. Nickel-titanium rotary instruments require a preclinical training period to minimize separation risks and should be used to case-related working lengths and apical widths. However, and despite superior in vitro results, randomized, clinical trials are required to evaluate outcomes when using nickel-titanium instruments.