CBCT in contemporary endodontics.

Cone-beam computed tomography (CBCT) is a three-dimensional imaging modality which can aid endodontic diagnosis and treatment planning. While there are guidelines available describing the indications, there are divergent philosophies on when this technology should be applied in clinical practice. This paper reviews the applications of CBCT including the clinical relevance of parameters which can be assessed, highlights the limitations of this technology, and provides guidance on how to maximise its clinical utility.

Prevalence and morphology of different root canal systems in mandibular premolars: a cross-sectional observational study.

BACKGROUND: This study investigated the prevalence and morphology of C-shaped and non-C-shaped root canal systems in permanent mandibular first (PM1) and second (PM2) premolars using retrospective analysis of cone-beam computed tomography (CBCT) scans, and panoramic radiographs. METHODS: CBCT scans from 2000 patients were screened for the presence of premolars with C-shaped canals and then assessed at three axial levels to determine the canal classification. The teeth were also assessed for Vertucci configuration, number of roots, and radicular grooves. Pre-existing panoramic radiographs were evaluated to identify features specific to PM1/2 with multiple canals or C-shaped anatomy. RESULTS: A total of 1576 PM1 and 1424 PM2 from 880 patients were evaluated. The overall prevalence of C-shaped canals was 2.2% (3.3% PM1, 1.0% PM2), with 49 (5.6%) patients presenting with at least one C-shaped mandibular premolar. There were 2.3 ± 0.6 and 2.4 ± 0.5 different classifiable cross-sections per tooth for PM1 and PM2, respectively. The sudden disappearance or bifurcation of a canal on panoramic radiographs was associated with the presence of multiple canals (P < 0.001) or C-shaped anatomy (P = 0.03). CONCLUSIONS: There was substantial variation in cross-sectional anatomy within and between C-shaped premolars, which will affect endodontic treatment planning. © 2023 Australian Dental Association.

Endodontic-orthodontic interactions: a review and treatment recommendations.

The literature is replete with articles describing the many and varied interactions between endodontic treatment and orthodontic tooth movement (OTM), often reporting conflicting views and findings, which creates confusion for clinicians. Original research and review articles have described aspects such as apical root resorption and potential pulpal complications of teeth related to OTM. Some interactions are of relatively minor clinical significance, whilst others may have adverse consequences. A history of dental trauma before or during OTM further complicates the interactions. This review re-assesses the historical literature on endodontic-orthodontic interactions in light of more recent research and presents guidelines for managing clinical situations involving both disciplines. © 2023 Australian Dental Association.

Biological considerations of dental materials as orifice barriers for restoring root-filled teeth.

There is ample published literature regarding the technical aspects of restoring root-filled teeth, but little concerning the biological impacts, consequences, and criteria for the selection of direct restorative materials following endodontic treatment. The provision of an effective coronal seal in addition to a sound root filling is known to be important in the prevention of root canal infection. This review seeks to explore the evidence concerning the selection of dental materials in the restoration of root-filled teeth, specifically with a close examination of the properties of commonly used materials as orifice barriers. © 2023 Australian Dental Association.

Current endodontic practice and use of newer technologies in Australia and New Zealand.

BACKGROUND: This study investigated endodontic clinical preferences, adoption of newer technologies and information sources among dentists and endodontists. METHODS: Dental and endodontic society members in Australia and New Zealand were surveyed online regarding their endodontic treatment preferences, armamentarium, information sources and continuing professional education (CPE) attendance. RESULTS: Complete responses were received from 71 endodontic specialists or postgraduates (Group E) and 139 general dentists (Group D). Most of Group E used dental operating microscopes (95.8%), endodontic cone-beam computed tomography (CBCT; 98.6%) and calcium silicate-based materials (CSBMs; 97.2%), significantly more (P < 0.001) than Group D (86.3% used loupes, <32% used CBCT for endodontics or CSBMs). Most respondents used dental dam always for endodontics (94.3%), electronic apex locators (EAL; 81.0%) and engine-driven nickel-titanium (NiTi) instruments (91.4%); Group E had more experience with engine-driven NiTi (P < 0.001). Endodontic CPE attendance was highest at dental association programs (P < 0.001) while hands-on NiTi training attendance was highest via commercial companies (P < 0.05). Online information sources were commonly used (38.8% of Group D, 59.2% of Group E). CONCLUSION: Dental dam, EAL and engine-driven NiTi were almost universally used. The endodontic group reported high adoption of newer endodontic technologies. Endodontic CPE and information sources should be further surveyed as online engagement evolves. © 2023 Australian Dental Association.

A critical evaluation of physical and manufacturing properties of genuine and counterfeit rotary nickel-titanium endodontic instruments.

BACKGROUND: Rotary nickel-titanium (NiTi) instruments are made to exacting standards and are costly to manufacture, and quality control is paramount. Consequently, unauthorized factories make counterfeit instruments that are less expensive and may therefore be attractive to dentists. Little information exists about the metallurgy and manufacturing quality of such instruments. There is the potential for counterfeit instruments to be at higher risk of fracture during treatment, thereby compromising clinical outcomes. The aim of this study was to evaluate physical and manufacturing properties of genuine and counterfeit ProTaper Next™ and Mtwo® rotary NiTi instruments. METHODS: This study investigated the metallurgical properties, manufacturing quality, microhardness and number of cycles to failure of two commonly used rotary NiTi systems and compared them with counterfeit products purporting to be genuine articles. RESULTS: Counterfeit instruments were found to be inferior in manufacturing standards and were less resistant to cyclic fatigue when compared to genuine instruments. CONCLUSIONS: Counterfeit rotary NiTi instruments may be less efficient at preparing root canals and may be at higher risk of fracture during endodontic treatment. Dentists must be aware that, although less expensive, counterfeit instruments may be of dubious manufacturing quality and at higher risk of fracture if used in patients. © 2023 Australian Dental Association.

Prevalence and morphology of C-shaped and non-C-shaped root canal systems in mandibular second molars.

BACKGROUND: There are no cone-beam computed tomography (CBCT)-based data on the anatomy of mandibular second molars in an Australian population. This study investigated the prevalence and descending morphology of mandibular second molars with and without C-shaped canals using retrospective analysis of CBCT scans. METHODS: Scans from 715 patients were screened for the presence of C-shaped canals and assessed for cross-sectional configuration at five axial levels. Non-C-shaped molars were assessed for other morphological characteristics. Data were modelled against patient, tooth and CBCT scan characteristics. RESULTS: A total of 1278 teeth from 657 patients were evaluated. The overall prevalence of C-shaped canals was 13%. Cross-sectional configuration of C-shaped canals was variable, with an average of 2.8 unique cross-sections per tooth. Non-C-shaped teeth were predominantly Vertucci Type II (60%) and Type IV (29%) configurations in mesial roots, and Type I (91%) in distal roots. Additional roots occurred in 4.3% of teeth and there was a significant association between radix paramolaris and distal root bifurcation (P < 0.001). CONCLUSIONS: Cross-sectional analysis confirmed the complexity and variability of C-shaped canals. Clinicians should be cognizant of the prevalence and variability of C-shaped root canal morphology and how this may affect endodontic treatment.

Dentinal microcracks and cemental tears related to chemo-mechanical root canal instrumentation: a micro-CT Cadaver Study.

BACKGROUND: The prevalence of radicular defects after root canal instrumentation is unresolved. This study used micro-CT to assess the relationship between the formation of radicular defects and chemo-mechanical instrumentation in a cadaver model. METHODS: Maxillary and mandibular molars (n = 24) were sectioned from cadaver specimens as a tissue block containing the teeth, alveolar bone and attached mucogingival tissues. After a baseline micro-CT scan (13.45 µm), the specimens were distributed into 3 groups (n = 8 molars): Reciproc® , ProTaper Next™ and Mtwo® . Micro-CT scans of each specimen were obtained after access, glide path and preparation with each instrument. The pre-operative and final post-operative micro-CT cross-sectional images of the roots were screened by two blinded examiners to identify any pre-existing and new radicular defects. Pre-existing and new radicular defects were examined histologically. RESULTS: Overall, 16 pre-existing radicular defects were identified in 12 of the 24 molars (50%). Most of these were cemental tears (87.5%), and not true dentinal microcracks. New dentinal microcracks were observed in the post-operative micro-CT scans of only 3 canals (3.9%; 3/77). However, only one of these defects was found to be present histologically. CONCLUSIONS: Within the limitations of the study, chemo-mechanical instrumentation did not routinely promote the formation of radicular defects.

Specialist Networks Influence Clinician Willingness to Treat Individuals with Special Needs.

BACKGROUND: The South Australian Dental Service's Special Needs Network was established to support oral health professionals working within their statewide government-funded dental service to treat patients with special needs. This study aimed to investigate how a structured network relationship with specialists in special needs dentistry influenced the willingness of dentists to treat this group of patients. METHODS: Semi-structured interviews were used to explore the views of specialists and dentists involved in the South Australian Dental Service's Special Needs Network. Inductive thematic analysis identified emerging themes enabling completion of a SWOT (strengths, weaknesses, opportunities, threats) analysis. RESULTS: Dentists felt that a strength of the Network was a greater sense of collegiality, particularly for those working in rural areas. Although the inability to get immediate advice was seen as a weakness, dentists felt a more structured relationship with specialists improved communication pathways and resulted in more timely care. The aging workforce, systemic barriers in the public dental system, such as productivity pressures and infrastructure, and the lack of support from other health professionals were seen as ongoing barriers and threats. Regardless, dentists identified the use of telehealth and visiting specialists as future opportunities. Specialists felt that the Network was a valuable resource but were skeptical about its effectiveness, feeling that a limitation was the ability of dentists to recognize the complexity of cases. CONCLUSIONS: Ongoing support from and communication with specialists in special needs dentistry through a structured network improved the perceived ability and willingness of dentists to treat patients with special needs. KNOWLEDGE TRANSFER STATEMENT: This research suggests that providing support to dentists through a hub-and-spoke network that facilitates additional training, professional interaction, and improved communication with specialists in special needs dentistry may help overcome some of the current barriers to access to care experienced by individuals with special needs, particularly those associated with the willingness and capability of clinicians treat them.

Root canal instrumentation efficacy of non-fused and fused primary molar roots: a micro-computed tomography study.

PURPOSE: Pulpectomy may be indicated in restorable primary teeth exhibiting irreversible pulpitis or pulpal necrosis. The purpose of this study was to compare the cleaning and shaping efficacy of NiTi systems (Reciproc® Blue and MTwo®) with manual stainless-steel instrumentation in primary molars using micro-CT analysis. METHODS: Fifty-seven maxillary second primary molars were scanned using micro-CT. Teeth with three divergent roots were divided randomly (n = 15) according to instrument type (K file, MTwo®, and Reciproc® Blue). Teeth with root fusion were instrumented manually as a separate group (n = 12). Pre- and post-instrumentation micro-CT images were superimposed, and the instrumentation area (IA) and procedural complications were recorded. RESULTS: No statistically significant differences in IA between file systems was observed in the non-fused teeth. The mean IA of fused roots was significantly lower than in the non-fused distobuccal (p = 0.003) and palatal (p < 0.001) roots. The root segment had a significant effect on IA (p < 0.001) and the highest mean IA was observed in the apical third. Manual instrumentation had fewer procedural complications compared with rotary systems. CONCLUSION: No differences were determined in the cleaning and shaping effectiveness of all systems in non-fused teeth. Uninstrumented areas (> 60%) occurred in both non-fused and fused primary teeth with fewer procedural complications observed after manual instrumentation.

Perspectives of the public dental workforce on the dental management of people with special needs.

BACKGROUND: People with special health care needs continue to have difficulties accessing regular dental care partly due to oral health professionals feeling they lack the knowledge and experience to provide treatment to these individuals. METHODS: Qualitative interviews and focus groups provided an insight into the types and nature of supports that oral health professionals working in the Australian public dental system desired and felt may improve their willingness and/or ability to treat patients with special needs. RESULTS: Although participants did not identify one group of patients with special needs that were more difficult to treat, they did report a feeling of being unsupported. Clinicians felt that improved training and access to ongoing education in Special Needs Dentistry, opportunities for greater support from specialists or other health professionals, either through networking or other media such as telehealth, and fostering a more supportive clinical environment, particularly in relation to appointment lengths and productivity pressures, may improve their willingness and ability to treat patients with special needs. CONCLUSIONS: Additional support, in the form of greater interaction with specialists and reduced time and productivity pressures, may improve the willingness of oral health professionals in the public dental system to treat patients with special needs.

Preferred Reporting items for OBservational studies in Endodontics (PROBE) guidelines: a development protocol.

Observational studies have a significant role in establishing the prevalence and incidence of diseases in populations, as well as determining the benefits and risks associated with health-related interventions. Observational studies principally encompass cohort, case-control, case series and cross-sectional designs. Inadequate reporting of observational studies is likely to have a negative impact on decision-making in day-to-day clinical practice; however, no reporting guidelines have been published for observational studies in Endodontics. The aim of this project is to develop reporting guidelines for authors when creating manuscripts describing observational studies in the field of Endodontology in an attempt to improve the quality of publications. The new guidelines for observational studies will be named: 'Preferred Reporting items for OBservational studies in Endodontics (PROBE)'. A steering committee was formed by the project leaders (PD, VN) to develop the guidelines through a five-phase consensus process. The steering committee will review and adapt items from the STrengthening the Reporting of OBservational studies in Epidemiology (STROBE) statement and the Clinical and Laboratory Images in Publications (CLIP) principles, as well as identify new items that add value to Endodontics. The steering committee will create a PROBE Delphi Group (PDG), consisting of 30 members across the globe to review and refine the draft checklist items and flowchart. The items will be assessed by the PDG on a nine-point Likert scale for relevance and inclusion. The agreed items will then be discussed by a PROBE Face-to-Face meeting group (PFMG) made up of 20 individuals to further refine the guidelines. After receiving feedback from the PFMG, the steering committee will pilot and finalize the guidelines. The approved PROBE guidelines will be disseminated through publication in relevant journals, and be presented at national and international conferences. The PROBE checklist and flowchart will be available and downloadable from the Preferred Reporting Items for study Designs in Endodontics (PRIDE) website: www.pride-endodonticguidelines.org. The PROBE steering committee encourages clinicians, researchers, editors and peer reviewers to provide feedback on the PROBE guidelines to inform the steering group when the guidelines are updated.

Root canal morphology of primary maxillary second molars: a micro-computed tomography analysis.

AIM: Successful endodontic treatment of primary teeth requires comprehensive knowledge and understanding of root canal morphology. The purpose of this study was to investigate the root canal configurations of primary maxillary second molars using micro-computed tomography. METHODS: Extracted human primary maxillary second molars (n = 57) were scanned using micro-computed tomography and reconstructed to produce three-dimensional models. Each root canal system was analysed qualitatively according to Vertucci's classification. RESULTS: 22.8% (n = 13) of the sample presented with the fusion of the disto-buccal and palatal roots; of these, Type V was the most prevalent classification. For teeth with three separate roots (n = 44), the most common root canal type was Type 1 for the palatal canal (100%) and disto-buccal canal (77.3%) and Type V for the mesio-buccal canal (36.4%). Overall, 7% (n = 4) of mesio-buccal canals were 'unclassifiable'. CONCLUSION: The root canal systems of primary maxillary second molars were not only complex but had a range of configurations that may contribute to unfavourable clinical outcomes after endodontic treatment.

Effect on the mechanical properties of human and bovine dentine of intracanal medicaments and irrigants.

BACKGROUND: Evidence is lacking concerning the suitability of using bovine dentine in endodontic research. This study compared the mechanical properties of human and bovine root dentine using endodontic medicaments and irrigants. METHODS: Standardized human and bovine dentine bars were allocated to six experimental groups (n = 15): calcium hydroxide paste (Calasept® Plus); Odontopaste® ; 0.5% and 1% NaOCl gels; 1% and 4% NaOCl solutions. The bars were exposed to the materials for 7 days and then immediately subjected to a three-point bend test and Vickers microhardness test. Data were analysed using analysis of variance with Fisher's pairwise comparisons, with P < 0.05. RESULTS: Human dentine displayed a significantly higher modulus of elasticity (P = 0.001), higher microhardness (P < 0.001), and lower flexural strength (P = 0.004) compared with bovine dentine. Calcium hydroxide and Odontopaste® did not result in a significant change to the mechanical properties of human dentine. In human dentine, 0.5% NaOCl gel caused a significant decrease in flexural strength (P < 0.001) and microhardness (P = 0.02). CONCLUSIONS: Bovine dentine was a suitable substrate relative to human dentine. The use of a 0.5% or 1% NaOCl gel as an intracanal medicament is not supported by this study.

In vitro fracture strength and patterns in root-filled teeth restored with different base materials.

BACKGROUND: There is little research on the effects of an intermediate base on the fracture strength of root-filled teeth. This study compared the fracture strengths and patterns of root-filled teeth restored with intermediate bases of glass-ionomer cement (GIC), zinc polycarboxylate cement (ZPC), dual-cured resin composite (DCRC) and Biodentine® under resin composite. METHODS: Standardized cavities were prepared in 100 extracted human maxillary and mandibular premolars, and root canal treatment was performed. The teeth were stratified and randomly allocated to five groups (n = 20): (i) GIC; (ii) ZPC; (iii) DCRC; (iv) Biodentine; and (v) prepared but unrestored (control). The teeth were subjected to an oblique, ramped load until fracture. The fracture loads, level, mode and location were recorded. RESULTS: Mean fracture strengths of all restored groups were not significantly different amongst the groups. There were significant overall effects on mean fracture strength for tooth type (P = 0.002) and buccolingual width of the crown (P = 0.001). CONCLUSIONS: The four materials were appropriate intermediate bases. The laminate restorative technique promoted fracture strengths that are likely to withstand normal and maximum masticatory function. The base material can influence failure mode, which may have implications for the clinical presentation of fractures of root-filled teeth.

A cross sectional and longitudinal study of endodontic and periapical status in an Australian population.

BACKGROUND: This study describes the cross sectional and longitudinal data of endodontic and periapical status of new patients presenting to a major dental hospital, and assesses the relationships between tooth-related variables with apical periodontitis. METHODS: The records of 695 patients were randomly selected and the orthopantomograms of these patients up to 31 October 2014 were reviewed by two endodontists. The periapical status of teeth was recorded using the periapical index. The presence and quality of root fillings and coronal restorations were recorded. Statistical analysis included Fleiss' kappa, Cohen's kappa and logistic regression set at P < 0.05. RESULTS: Of 695 patient records and 16 936 teeth examined, 138 (19.9%) patients or 284 (1.7%) teeth had root fillings and 179 (25.8%) patients or 325 (1.9%) teeth had apical periodontitis. Root fillings and coronal restorations were adequate in 34.6% and 69.4% teeth, respectively. A large proportion (47%) of teeth with apical periodontitis remained unchanged in subsequent orthopantomograms. CONCLUSIONS: There was lower prevalence of root filled teeth or apical periodontitis in the present study compared with international studies. The frequency of adequate root fillings must be considered unacceptably low. Teeth with apical periodontitis may remain quiescent in the absence of caries or restorative breakdown.

Sterilization of rotary NiTi instruments within endodontic sponges.

AIM: To determine whether the following can be sterilized by autoclaving - endodontic sponges, rotary nickel-titanium (NiTi) instruments within endodontic sponges, and rotary NiTi instruments with rubber stoppers. METHODOLOGY: Sixty-four samples of eight different endodontic sponges (n = 512) were placed into brain heart infusion broth (BHI) for 72 h. An aliquot of this was then spread onto horse blood agar and cultured aerobically and anaerobically to test sterility at purchase. Bacterial suspensions of Enterococcus faecalis, Porphyromonas gingivalis and Geobacillus stearothermophilus in BHI were used to contaminate sterile sponges and rotary NiTi instruments (with and without rubber stoppers) inserted into sponges. The various samples were autoclaved and then cultured aerobically and anaerobically. Success of sterilization was measured qualitatively as no growth. The experiment was repeated with clinically used rotary NiTi instruments (n = 512). All experiments were conducted in quadruplicate. RESULTS: No sponges on purchase had microbial growth when anaerobically cultured but some did when aerobically cultured. All autoclaved sponges and instruments (within or without sponges, and with or without rubber stoppers) were associated with no microbial growth. All nonautoclaved positive control samples showed microbial growth. CONCLUSIONS: Autoclaving was effective in the sterilization of sponges and endodontic instruments. Endodontic sponges should be autoclaved before clinical use. For clinical efficiency and cost-effectiveness, rotary NiTi instruments can be sterilized in endodontic sponges without removal of rubber stoppers.

Endodontics and the ageing patient.

Patients are living longer and the rate of edentulism is decreasing. Endodontic treatment is an essential part of maintaining the health and well-being of the elderly. Retention of natural teeth improves the quality of life and the overall health and longevity of ageing patients. Also, teeth that might be otherwise extracted may be strategically valuable to retain a prosthesis, and elderly patients are more likely to have medical complications that may prevent dental extractions from being safely performed. The technical goals of endodontic treatment in the elderly are the same as those for younger patients. However, the pulpo-dentinal complex undergoes calcific changes over time, which may pose challenges for the clinician. The purposes of this review are to discuss age changes in the pulp and the challenges posed by diagnosing, treatment planning and treating the elderly endodontic patient.

Reporting dental trauma and its inclusion in an injury surveillance system in Victoria, Australia.

BACKGROUND: This study investigated the frequency, patterns and causes of dental trauma in patients seeking emergency treatment at a dental hospital, and evaluated the impact of an electronic structured injury history form to collect key information. METHODS: A retrospective audit was undertaken of all emergency presentations at the Royal Dental Hospital of Melbourne from 2009 to 2012. Dental trauma and injury surveillance data were collected and evaluated with reference to the criteria of the Victorian Emergency Minimum Dataset. Statistical analysis included chi-squared and Fisher's exact tests. RESULTS: A total of 88,610 new emergency courses of care were created, with 3642 (4.1%) identified as new dental trauma cases in 3574 patients. A total of 6001 teeth were injured with a mean of 1.7 teeth per patient (range: 1-8 teeth). The improvement of injury surveillance information collected using the electronic form compared with the paper form was statistically significant (p<0.001). CONCLUSIONS: The dental trauma findings of this study are consistent with other studies regarding age, gender, location, cause and injury type. This study also confirmed the benefits of electronic collection of dental injury surveillance data that can assist policy planners and health service providers in designing and delivering effective dental injury prevention and management services.

Factors influencing root canal retreatment strategies by general practitioners and specialists in Australia.

AIM: To evaluate the effect of tooth radiographic features on root canal retreatment strategies used by general dental practitioners and dental specialists in Australia. METHODS: A descriptive survey study comprising a web-based questionnaire was sent to general dental practitioners and specialists. The questionnaire diagrammatically represented six different clinical scenarios with variables including type of coronal restoration, quality of root filling and the size and presence of a periapical radiolucency. Treatment options included no treatment, orthograde retreatment, periapical surgery and replacement with an implant. For each of the six scenarios, the participant was asked to select a minimum size cut-off point where treatment would be initiated and also indicate the preferred treatment option. RESULTS: A total of 639 questionnaires were submitted online. In teeth without a cast core restoration, the quality of root filling influenced the selection of no treatment as an option (P < 0.001). The presence of a cast post/core restoration influenced both the treatment cut-off point and treatment option, with more practitioners selecting larger lesions as cut-off points (P < 0.001) and more treatment options involving both implant placement (P < 0.001) and periapical surgery (P < 0.001). With more complex treatment planning (i.e. cast post/core restorations and inadequate root filling), general practitioners proposed implant placement more readily compared with specialists (P < 0.001). CONCLUSIONS: General practitioners and specialists vary their root canal retreatment strategies according to quality of root filling and type of coronal restoration. Whilst all clinical scenarios could be managed by contemporary endodontic techniques, teeth were still treatment planned for extraction and replacement with an implant. This may be due to the fact that implants are heavily marketed by the dental industry and with more stringent outcome criteria applied to the assessment of root canal treatment compared with implant placement, evidence-based decision-making may be distorted. Future emphasis should be placed on changing practitioners' attitudes towards the retention of salvageable teeth by contemporary endodontic measures.