Application of a new system for classifying root and canal anatomy in studies involving micro-computed tomography and cone beam computed tomography: Explanation and elaboration.

Adequate knowledge and accurate characterization of root and canal anatomy is an essential prerequisite for successful root canal treatment and endodontic surgery. Over the years, an ever-increasing body of knowledge related to root and canal anatomy of the human dentition has accumulated. To correct deficiencies in existing systems, a new coding system for classifying root and canal morphology, accessory canals and anomalies has been introduced. In recent years, micro-computed tomography (micro-CT) and cone beam computed tomography (CBCT) have been used extensively to study the details of root and canal anatomy in extracted teeth and within clinical settings. This review aims to discuss the application of the new coding system in studies using micro-CT and CBCT, provide a detailed guide for appropriate characterization of root and canal anatomy and to discuss several controversial issues that may appear as potential limitations for proper characterization of roots and canals.

Comparing the anaesthetic efficacy of 1.8 mL and 3.6 mL of anaesthetic solution for inferior alveolar nerve blocks for teeth with irreversible pulpitis: a systematic review and meta-analysis with trial sequential analysis.

BACKGROUND: The scientific literature is contradictory in relation to selecting the appropriate volume of local anaesthetic solution for inferior alveolar nerve blocks (IANB) when attempting to anaesthetize mandibular teeth with irreversible pulpitis. OBJECTIVES: To compare the efficacy of 1.8 and 3.6 mL of the same anaesthetic solution for IANBs when treating mandibular teeth with irreversible pulpitis. METHODS: A literature search was performed in PubMed, Scopus and EBSCOhost databases until May 2020. Randomized clinical trials published in English, comparing 1.8 with 3.6 mL of the same anaesthetic solution for IANBs in permanent mandibular teeth with irreversible pulpitis, were included. The risk of bias of the included trials was appraised using the revised Cochrane risk of bias tool. A meta-analysis was performed using the random-effects model. The effect of random errors on the results of the meta-analysis was evaluated by trial sequential analysis and the quality of evidence was appraised using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. RESULTS: Four clinical trials involving 280 teeth from patients with ages ranging from 18 to 65 years were included. Among the four trials, three were categorized as having a 'low' risk of bias and one was categorized as having 'some concerns'. The primary meta-analysis revealed that 3.6 mL of anaesthetic solution when administered for IANBs was associated with significantly greater success rates compared with 1.8 mL (RR = 1.94; 95% CI, 1.07, 3.52; I2  = 77%). Similarly, the results of the sensitivity analysis (restricting trials only to those that used the Heft-Parker visual analogue pain scale) revealed that the use of 3.6 mL significantly increased the success of IANBs compared with 1.8 mL. The trial sequential analysis confirmed the evidence for the beneficial effect of 3.6 mL to achieve success for IANBs was 'conclusive'. The quality of evidence was graded as 'high'. CONCLUSION: Increasing the volume of anaesthetic solution from 1.8 to 3.6 mL improved the success rate for IANBs in mandibular molars with irreversible pulpitis. The quality of the evidence was 'high'. Future high-quality clinical trials are required with different types of anaesthetic solutions and other types of teeth.

Application of a new system for classifying root canal morphology in undergraduate teaching and clinical practice: a national survey in Malaysia.

AIM: To evaluate and compare the feedback of final year undergraduate dental students in eight Malaysian dental schools on the application of a new system for classifying root canal morphology in teaching and clinical practice. METHODS: One PowerPoint presentation describing two classification systems for root canal morphology (Oral Surgery Oral Medicine Oral Pathology, 1974 38, 456 and its supplemental configurations, International Endodontic Journal 2017, 50, 761) was delivered to final year undergraduate dental students in eight dental schools in Malaysia by two presenters (each presented to four schools). To examine students' feedback on the utility of each system, printed questionnaires consisting of six questions (five multiple choice questions and one open-ended question) were distributed and collected after the lecture. The questionnaire was designed to compare the classification systems in terms of accuracy, practicability, understanding of root canal morphology and recommendation for use in pre-clinical and clinical courses. The exact test was used for statistical analysis, with the level of significance set at 0.05 (P = 0.05). RESULTS: A total of 382 (out of 447) students participated giving a response rate of 86%. More than 90% of students reported that the new system was more accurate and more practical compared with the Vertucci system (P < 0.001). Overall, 97% of students reported the new system helped their understanding of root and canal morphology compared with the Vertucci classification (P < 0.001). Over 97% of students recommended the use of the new system in teaching, pre-clinical courses and clinical practice (P < 0.001). Except for two schools, no significant difference was detected between the responses of students for all questions at the different schools (P > 0.05). The students' responses for all questions were almost similar for both presenters (P > 0.05). CONCLUSIONS: The new system of International Endodontic Journal 2017, 50, 761 for classifying root and canal morphology was favoured by final year undergraduate dental students in Malaysia. The new system has the potential to be included in the undergraduate endodontic curriculum for teaching courses related to root and canal morphology.

A bibliometric study of the top 100 most-cited randomized controlled trials, systematic reviews and meta-analyses published in endodontic journals.

AIM: To identify and analyse the main features of the top 100 most-cited randomized controlled trials, systematic reviews and meta-analyses published in endodontic journals from 1961 to 2018. METHODOLOGY: The Clarivate Analytics' Web of Science 'All Databases' was used to search and analyse the 100 most frequently cited randomized controlled trials, systematic reviews and meta-analyses having 'randomized', 'randomised', 'randomized controlled', 'randomised controlled', 'randomized controlled trial', 'randomized controlled trials', 'clinical trial', 'systematic', 'systematic review', 'meta-analysis', and 'meta-analyses' in the title section. The 'International Endodontic Journal', 'Journal of Endodontics', 'Oral Surgery Oral Medicine Oral Pathology Oral Radiology and Endodontology', 'Australian Endodontic Journal', 'Endodontics & Dental Traumatology', 'Endo-Endodontic Practice Today' and 'European Endodontic Journal' were included in the publication name section. After ranking the articles in a descending order based on their citation counts, each article was cross-matched with the citation counts in Elsevier's Scopus and Google Scholar. The articles were analysed, and information on citation counts, citation density, year of publication, contributing authors, institutions and countries, journal of publication, study design, topic of the article and keywords was extracted. RESULTS: The citation counts of the 100 most-cited articles varied from 235 to 20 (Web of Science), 276 to 17 (Scopus) and 696 to 1 (Google Scholar). The year in which the top 100 articles were published was 2010 (n = 13). Among 373 authors, the greatest number of articles was associated with three individuals namely Reader A (n = 5), Beck M (n = 5) and Kvist T (n = 5). Most of the articles originated from the United States (n = 24) with the greatest contribution from Ohio State University (USA) (n = 5). Randomized controlled trials were the most frequent study design (n = 45) followed by systematic reviews (n = 30) with outcome studies of root canal treatment being the major topic (n = 35). The Journal of Endodontics published the largest number of included articles (n = 70) followed by the International Endodontic Journal (n = 27). Among 259 unique keywords, meta-analysis (n = 23) and systematic review (n = 23) were the most frequently used. CONCLUSION: This study has revealed that year of publication had no obvious impact on citation count. The bibliometric analysis highlighted the quantity and quality of research, and the evolution of scientific advancements made in the field of Endodontology over time. Articles before 1996, that is prior to the CONSORT statement that encouraged authors to include specific terms in the title and keywords, may not have been included in this electronic search.

Shaping ability of BioRace, ProTaper NEXT and Genius nickel-titanium instruments in curved canals of mandibular molars: a MicroCT study.

AIM: To evaluate and compare the canal shaping ability of BioRace, ProTaper NEXT and Genius engine-driven nickel-titanium (NiTi) file systems in extracted mandibular first molars using micro-computed tomography (MCT). METHODOLOGY: Sixty mesial root canals of mandibular first molars were randomly divided into three equal groups, according to the instrument system used for root canal preparation (n = 20): BioRace (BR), ProTaper NEXT (PTN) or Genius (GN). Root canals were prepared to the full WL using a crown-down technique up to size 35, .04 taper instruments for BR and GN groups and size 30, .07 taper instruments for the PTN group. MCT was used to scan the specimens before and after canal instrumentation. Changes in dentine volume, the percentage of uninstrumented canal surface and degree of canal transportation were evaluated in the coronal, middle and apical thirds of canals. Data were analysed statistically using one-way analysis of variance and Tuckey's post hoc tests with the significance level set at 5%. RESULTS: There were no significant differences between the three groups in the terms of dentine removed after preparation and determination of the root canal volume, or percentage of uninstrumented canal surface (P > 0.05). No significant differences were found between the systems for canal transportation in any canal third (P > 0.05). CONCLUSIONS: The shaping ability of the BR, PTN and GN NiTi file systems was equally effective. All instrumentation systems prepared curved root canal systems with no evidence of undesirable changes in 3D parameters or significant shaping errors.

The role of stem cell therapy in regeneration of dentine-pulp complex: a systematic review.

Infection of the dental pulp will result in inflammation and eventually tissue necrosis which is treated conventionally by pulpectomy and root canal treatment. Advances in regenerative medicine and tissue engineering along with the introduction of new sources of stem cells have led to the possibility of pulp tissue regeneration. This systematic review analyzes animal studies published since 2010 to determine the ability of stem cell therapy to regenerate the dentine-pulp complex (DPC) and the success of clinical protocols. In vitro and human clinical studies are excluded and only the experimental studies on animal models were included. Dental pulp stem cells constitute the most commonly used cell type. The majority of stem cells are incorporated into various types of scaffold and implanted into root canals. Some of the studies combine growth factors with stem cells in an attempt to improve the outcome. Studies of ectopic transplantation using small animal models are simple and non-systematic evaluation techniques. Stem cell concentrations have not been so far reported; therefore, the translational value of such animal studies remains questionable. Though all types of stem cells appear capable of regenerating a dentine-pulp complex, still several factors have been considered in selecting the cell type. Co-administrative factors are essential for inducing the systemic migration of stem cells, and their vascularization and differentiation into odontoblast-like cells. Scaffolds provide a biodegradable structure able to control the release of growth factors. To identify problems and reduce costs, novel strategies should be initially tested in subcutaneous or renal capsule implantation followed by root canal models to confirm results.

Antibiotic prescribing for endodontic therapies: a comparative survey between general dental practitioners and final year Bachelor of Dental Surgery students in Cardiff, UK.

AIM: To evaluate the views of final year dental surgery students (BDS; G1) at Cardiff University and general dental practitioners (GDPs; G2) within the geographic area of Cardiff, Wales, on antibiotic prescribing for endodontic conditions, and investigate the potential differences between the two groups. METHODS: A cross-sectional online questionnaire-based survey of 12 qualitative and quantitative questions was distributed to 76 final year BDS Cardiff University students and 55 dental practices within Cardiff, UK. Six questions recorded general information, and the remaining questions included a series of hypothetical clinical scenarios, where the participants were asked to state whether they would or would not prescribe antibiotics. The data were analysed using spss version 23 to produce descriptive statistics, contingency tables and to run chi-square (χ²) tests, Fisher's exact tests and relative risk calculations. RESULTS: The response rate was 60% (n = 79). All G1 participants were aware of the consequences of antibiotic overuse. Approximately 60% of responders were aware of guidelines for antibiotic use in endodontic therapies, and 83% would only use antibiotics for a limited selection of patients (e.g. patients with systemic complications). G1 responses to clinical scenarios indicated overall that they were comparable to the ideal answers except for acute apical abscess (64% believed that antibiotics were indicated). The majority of G2 were aware of the consequences of antibiotic overuse. Only 28% of G2 were aware of guidelines for antibiotic use in endodontic therapies. Overall responses revealed that antibiotics would be prescribed for: systemic complications (78%), acute apical abscess (72%) and symptomatic apical periodontitis (28%). The clinical scenarios revealed G1 were more likely to prescribe antibiotics compared to G2 for cases of necrotic pulp with symptomatic apical periodontitis without systemic complications (incorrect answer) and less likely to other clinical scenarios such as necrotic pulp and asymptomatic apical periodontitis for patients with a history of rheumatic fever (ideal answers), symptomatic irreversible/reversible pulpitis, failure to achieve anaesthesia, chronic apical abscess for patients with diabetes. The recognition of antibiotic prescription for cases with signs of spreading infection was more evident in G2. CONCLUSION: Final year undergraduate students were aware of the antibiotic resistance crisis, although a third was not aware of guidelines for use of antibiotics in endodontic conditions; their responses to clinical scenario were generally compatible with the guidelines. General dentists were less aware of the implications of overuse of antibiotics and the existence of guidelines, and their responses were occasionally incompatible with antibiotic guidelines for endodontic therapies.

A new system for classifying tooth, root and canal anomalies.

Understanding the normal anatomical features as well as the more unusual developmental anomalies of teeth, roots and root canals is essential for successful root canal treatment. In addition to various types of root canal configuration and accessory canal morphology, a wide range of developmental tooth, root and canal anomalies exists, including C-shaped canals, dens invaginatus, taurodontism, root fusion, dilacerations and palato-gingival grooves. There is a direct association between developmental anomalies and pulp and periradicular diseases that usually require a multidisciplinary treatment approach to achieve a successful outcome. A number of classifications have categorized tooth, root and canal anomalies; however, several important details are often missed making the classifications less than ideal and potentially confusing. Recently, a new coding system for classifying root, root canal and accessory canal morphology has been introduced. The purpose of this article is to introduce a new system for classifying tooth, root and canal anomalies for use in research, clinical practice and training, which can serve as complementary codes to the recently described system for classifying root, as well as main and accessory canal morphology.

A survey of adoption of endodontic nickel-titanium rotary instrumentation part 1: general dental practitioners in Wales.

OBJECTIVE: To assess adoption of endodontic nickel-titanium (NiTi) rotary technology by general dental practitioners and identify factors influencing its uptake. DESIGN: Postal questionnaire. SETTING: General dental practitioners working in Wales. METHODS: General dental practitioners (n = 584) were approached regarding their usage or otherwise of nickel-titanium rotary instrumentation during root canal shaping. The postal questionnaire took the form of an anonymous survey comprising 13 questions. These questions covered usage parameters, satisfaction, training issues and reasons for avoidance of NiTi instruments. RESULTS: The response rate was 71%. Nickel-titanium rotary instruments were used routinely by 67% of those responding practitioners. Principle factors cited as being implicated in the decision to not adopt NiTi use included cost (65% of responses), lack of training and the perceived risk of instrument fracture. CONCLUSIONS: Over two thirds of dental practitioners in Wales use rotary NiTi endodontic technology with the majority having converted to such systems more than three years ago. There was, however, a significant disparity in NiTi usage between solely NHS practitioners (42%) and private practitioners (90%). Continued provision of high quality hands-on practical workshops may be of benefit in facilitating a positive initial NiTi experience in order to assist the transfer to these newer technologies.

A survey of adoption of endodontic nickel-titanium rotary instrumentation part 2: community and hospital dental practitioners in Wales.

OBJECTIVES: To assess adoption of endodontic nickel-titanium rotary technology (NiTi) by community and hospital dental clinicians within Wales and identify factors that may restrict uptake. DESIGN: Postal questionnaire. SETTING: Community and hospital-based dentists in Wales. METHODS: Community and hospital-based dentists with a remit for provision of restorative dentistry (community dental setting = 32; hospital dental setting = 36) were approached regarding their usage or otherwise of nickel-titanium rotary instrumentation for endodontic treatments. The postal questionnaire took the form of an anonymous survey comprising 12 questions. These questions covered usage parameters, satisfaction and training and broached reasons for NiTi avoidance. RESULTS: The response rate was 77%. NiTi rotary instruments were used routinely by an encouraging 82% of those in the hospital-based restorative dental services but only 13% of community staff. Factors cited as being implicated in the decision to avoid their use included cost (62% of responses) lack of training and the perceived lack of benefit. CONCLUSION: The adoption of rotary NiTi endodontic technology by the hospital dental practitioners of Wales is encouraging with the majority having converted to such systems in excess of three years prior to the survey. There was, however, a significant disparity in NiTi usage between community and hospital settings, the implications for which and possible solutions for increased training and uptake are discussed.

Unintentional extrusion of mineral trioxide aggregate: a report of three cases.

AIM: Mineral trioxide aggregate (MTA) is the material of choice for apical barrier techniques during root canal treatment of teeth with open apices. However, the precise control of MTA during the placement of an apical plug is challenging. This article describes the outcomes of unintentional extrusion of MTA into the periradicular tissue during apical barrier treatment in three cases. SUMMARY: Three cases of maxillary central incisors in adult patients with open apices were referred for treatment. After conventional access and canal preparation, MTA was placed into the apical portion of the root canals to act as an apical barrier/plug. A large increment of MTA was extruded in all cases. In Case 1, after a 4-year follow-up, the extruded MTA had resorbed and the periradicular lesion had healed. In Cases 2 and 3, after follow-up, the patients remained symptomatic and were scheduled for periradicular surgery. In Case 2, soft unset particles of MTA were present in the lesion and were curetted. In Case 3, the extruded MTA had set hard but was sandwiched between the oral mucosa and bone; its removal relieved the pain experienced on buccal palpation. KEY LEARNING POINTS: Extruded MTA may not harden and may be associated with ongoing periapical irritation; Extruded set MTA when encapsulated in the mucosa and not surrounded by bony matrix may act as a mechanical irritant on palpation; Mineral trioxide aggregate should be confined to the root canal system; Teeth where MTA has been extruded beyond the foramen should be followed-up to monitor the outcome.

Pulp canal obliteration: an endodontic diagnosis and treatment challenge.

AIM: To review the literature on pulp chamber and root canal obliteration in anterior teeth and to establish a clear protocol for managing teeth with fine, tortuous canal systems. SUMMARY: Pulp canal obliteration (PCO) occurs commonly following traumatic injuries to teeth. Approximately 4-24% of traumatized teeth develop varying degrees of pulpal obliteration that is characterized by the apparent loss of the pulp space radiographically and a yellow discoloration of the clinical crown. These teeth provide an endodontic treatment challenge; the critical management decision being whether to treat these teeth endodontically immediately upon detection of the pulpal obliteration or to wait until symptoms or signs of pulp and or periapical disease occur. The inevitable lack of responses to normal sensibility tests and the crown discoloration add uncertainty to the management; however, only approximately 7-27% of teeth with PCO will develop pulp necrosis with radiographic signs of periapical disease. Root canal treatment of teeth with pulpal obliteration is often challenging. This article discusses the various management approaches and highlights treatment strategies for overcoming potential complications. KEY LEARNING POINTS: Up to 25% of traumatized anterior teeth can develop pulp canal obliteration; Discolouration is a common clinical finding in teeth with pulp canal obliteration; Up to 75% of teeth with pulp canal obliterations are symptom-free and require no treatment other than radiographic monitoring; Routine pulp sensibility tests are unreliable in the presence of pulp canal obliteration; Teeth with pulp canal obliteration in need of root canal treatment pose particular diagnostic and treatment challenges.

Use of cone-beam computed tomography to evaluate root and canal morphology of mandibular molars in Chinese individuals.

AIM: To evaluate the root canal configuration of permanent mandibular first and second molar teeth in a Chinese subpopulation using cone-beam computed tomography (CBCT). METHODOLOGY: Patients who required CBCT radiographic examinations as part of their routine examination, diagnosis and treatment planning, were enrolled. Cases where the anatomy was compromised by physiological or pathological processes and the original root canal morphology was not clear were excluded. A total of 389 healthy, untreated, fully developed mandibular molars in Chinese individuals were included. The following observations were recorded: (i) the number of roots and their morphology; (ii) the number of canals per root; (iii) the canal configuration; (iv) the frequency of distolingual roots in the mandibular first molars and (v) the frequency of C-shaped canals in the mandibular second molars. The root canal configurations were classified according to the method of Vertucci (Oral Surgery, Oral Medicine, and Oral Pathology58, 1984, 589). RESULTS: The majority of mandibular molars (70% of first molars, 76% of second molars) had two separate roots; however, three roots were identified in 29% of first molars. C-shaped roots occurred in 29% of second molars. Three canals were found in 56% of mandibular first molars and 43% had four canals. In the mandibular second molars, 46% had three canals and 38% had two canals. Most distal roots had a simple type I configuration, whereas mesial roots had more complex canal systems, with more than one canal. There were seven variants of the root canal morphology amongst the mandibular first molars and eight variants amongst the mandibular second molars, without considering the various root types. CONCLUSIONS: Three-rooted mandibular first molars and C-shaped mandibular second molars occurred frequently in this Chinese population. CBCT is an effective tool for the detection of additional distolingual roots and C-shaped roots/canals, and it is a valuable aid for dentists providing root canal treatment.

A comparative study of image quality and radiation exposure for dental radiographs produced using a charge-coupled device and a phosphor plate system.

AIM: To investigate the quality of periapical radiographic images produced by two digital dental radiography systems, a charge-coupled device (CCD) and a photostimulable phosphor (PSP) image plate system, and to examine the overall radiation exposure when using these systems in a clinical setting. METHODOLOGY: Patients were randomly allocated to both systems and the resultant radiographs rated for quality. The expected radiation exposure for an investigation was calculated. RESULTS: Overall, 98 images were acquired using the CCD system and 108 with the PSP system. The PSP system produced significantly higher quality (P < 0.001) periapical images compared with the CCD system. The CCD system required significantly more (P < 0.001) repeat exposures to obtain a diagnostic image than the PSP system but at a lower expected radiation exposure. CONCLUSIONS: The image quality was superior using the phosphor plate system. Although more repeat radiographs were required using the CCD system, the images were produced with a lower expected radiation exposure.

Consequences of and strategies to deal with residual post-treatment root canal infection.

Bacterial sampling of prepared root canals is used to determine the presence and character of the remaining microbiota. However, it is likely that current sampling techniques only identify organisms in the main branches of the root canal system whereas it is unlikely that they can sample areas beyond the apical end-point of preparation and filling, or in lateral canals, canal extensions, apical ramifications, isthmuses and within dentinal tubules. Thus, it may be impossible by current techniques to identify residual post-treatment root canal infection. In histologic observations of root apices, bacteria have been found in inaccessible inter-canal isthmuses and accessory canals often in the form of biofilms. There is no in vivo evidence to support the assumption that these bacteria can be entombed effectively in the canal system by the root filling and thus be rendered harmless. As a consequence of this residual root infection, post-treatment apical periodontitis, which may be radiographically undetectable, may persist or develop as a defence mechanism to prevent the systemic spread of bacteria and/or their byproducts to other sites of the body. Histologic observation of root apices with surrounding bone removed from either patients or human cadavers has demonstrated that post-treatment apical periodontitis is associated with 50-90% of root filled human teeth. Thus, if the objective of root canal treatment is to eliminate apical periodontitis at a histological level, current treatment procedures are inadequate. It is essential that our knowledge of the local and systemic consequences of both residual post-treatment root infection and post-treatment apical periodontitis be improved. The continued development of treatments that can effectively eliminate root infection is therefore a priority in clinical endodontic research. Post-treatment disease following root canal treatment is most often associated with poor quality procedures that do not remove intra-canal infection; this scenario can be corrected via a nonsurgical approach. However, infection remaining in the inaccessible apical areas, extraradicular infection including apically extruded dentine debris with bacteria present in dentinal tubules, true radicular cysts, and foreign body reactions require a surgical intervention.