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Guidelines were developed by the Australian Society of Endodontology Inc. with the intent to describe relevant aspects of contemporary evidence‐based root canal treatment. The document aims to support clinicians by describing a Standard of Practice in the Australian context. The presented guidelines refer to Competence criteria and Quality standards for the main steps in root canal treatment. While the intent is not to replace individual clinical decision‐making, it is envisaged that these periodically reviewable guidelines may help to improve clinical outcomes. [ABSTRACT FROM AUTHOR]

Background: There is an increased tendency towards adopting minimally invasive interventions in dentistry, supported by advancement in materials and techniques. However, the decision‐making process in choosing conservative or invasive treatments is influenced by several factors, particularly in permanent teeth with irreversible pulpitis. Objectives: The objective of the study was to systematically review the literature regarding factors that influence decision‐making for vital pulp therapy (VPT) as definitive treatment option in permanent mature teeth diagnosed with irreversible pulpitis. Methods: Two independent reviewers searched five electronic databases (PubMed, Embase, Web of Science, Scopus and Cochrane Library). Grey literature was searched through Google Scholar and contact with experts. Defined search keys were applied, and all peer‐reviewed literature published with no language nor publication date limits were included. The All studies investigating the factors influencing treatment decision‐making in mature permanent teeth with irreversible pulpitis were included. The quality of included studies was assessed by two independent reviewers using the Joanna Briggs Institute quality assessment tool. Results: Six articles were included in the review. All included studies used questionnaires to characterize clinician preferences and attitudes in choosing treatment options for mature permanent teeth with irreversible pulpitis. The available evidence suggests that dentist‐related factors have a significant influence on the chosen treatment in teeth with irreversible pulpitis, with speciality training and years of experience influencing the choice of VPT over other treatment options. COVID‐19 reportedly swayed the dentists' decision to favour VPT. Only one article studied the influence of patient‐related factors, such as age and presence of spontaneous pain on decision‐making. Of note, a history of cardiovascular disease moved dentists towards prescribing VPT. Discussion: Collectively, the included studies demonstrated an overriding influence of dentist‐related factors on choosing among treatment options for painful teeth diagnosed with irreversible pulpitis. Patient‐related factors were acknowledged but there are also potential factors such as socio‐economic constraints that were not included in the component studies. Conclusion: In teeth with irreversible pulpitis clinicians educational background influence the decision towards a specific treatment option. Further data, preferably derived from clinical records, is necessary in future investigations to explore the effect of other important factors related to both dentists and patients. Registration: PROSPERO database (CRD42022339653). [ABSTRACT FROM AUTHOR]

A partial or complete pulpotomy is a type of vital pulp therapy (VPT) that aims to remove the inflamed, infected pulp, leaving behind healthy, vital pulp that is capable of healing. VPT has gained renewed popularity as a treatment option in permanent mature posterior teeth with irreversible, moderate to severe pulpitis; its high success rates matching that of root canal treatment (RCT). There is currently no consensus regarding diagnostic and prognostic predictors of success of pulpotomies for managing such cases. Therefore, we conducted a scoping review to identify and analyze how these factors affect the outcome of treatment. A literature search using the PRISMA guidelines was undertaken using PubMed and Scopus on 7 July 2023. A total of 22 studies met the inclusion criteria and were qualitatively analyzed by two reviewers. The following diagnostic and prognostic factors were recognized and discussed; presenting signs and symptoms, periapical diagnosis, bleeding time, indicators of inflammation (bleeding time, concentration of inflammatory biomarkers), patient age and medical status, the depth, activity and location of caries, and restorative factors. Based on the studies assessed, there is limited evidence to support their prognostic value. Further research is necessary to identify solid predictors of outcome. [ABSTRACT FROM AUTHOR]

This systematic review aimed to investigate whether root canal treatment caused greater stress than other dental treatments for patients and dentists. All peer‐reviewed literature published in English between January 1990 and January 2023 was included. This included randomized/non‐randomized control trials, cohort studies, case‐control studies, and cross‐sectional studies. An electronic search used PubMed, Scopus, Medline, Cochrane Collaboration, and Embase. Hand searching supplemented the screening pool. Studies examining physiological or psychological stress measures within patients or providers of dental treatment (dentists, dental specialists, and dental students) were eligible. The study must have reported on the stress outcome for root canal treatment and at least one other dental procedure. After screening 3639 eligible records, there were 23 studies included, varying from very‐low to low certainty of evidence. This review found that root canal treatment was more psychologically stressful for patients than routine restorative or cleaning procedures. However, the stress of root canal treatment relative to other dental procedures, especially extractions, was inconclusive for both dental patients and providers. Since patients regard root canal treatment as more stress‐evoking than other routine dental procedures, providers should endeavour to minimise their own bias toward root canal treatment when providing adequate information for an informed treatment choice. [ABSTRACT FROM AUTHOR]

The article explores the concept of the Metaverse and its potential applications in the field of endodontics. The Metaverse is a virtual reality universe that combines elements of the physical and digital worlds, allowing for real-time communication and dynamic interactions with digital objects. In the context of endodontics, the Metaverse could be used for patient-clinician consultations, digital education, diagnostics, and therapeutics. It offers the possibility of remote dental consultations, reducing the need for travel and wait times, while also reducing anxiety and fear in patients. The integration of the Internet of Dental Things (IoDT) with the Metaverse presents opportunities for advancements in dentistry, such as the use of wearable oral sensors for early detection of dental caries. The Metaverse also enables collaboration among specialists and provides virtual educational models for dental students. Additionally, advanced metaverse headsets can enhance precision in root canal treatments and provide pain relief for patients. However, challenges such as data privacy and technological limitations need to be addressed. Overall, further exploration and evaluation are needed to determine the effectiveness and safety of Metaverse technology in endodontics. [Extracted from the article]

These may be related to a "structure" (such as anatomy), a "disease" (such as pulp and periapical diseases), a "material" (such as bioceramic materials) or a "procedure" (such as diagnostic and root canal treatment procedures). Consensus, controversial terms, endodontics, root canal treatment, glossary 5 Ahmed, H.M.A., Versiani, M.A., De-Deus, G. & Dummer, P.M.H. (2017) A new system for classifying root and root canal morphology. Keywords: consensus; controversial terms; endodontics; glossary; root canal treatment EN consensus controversial terms endodontics glossary root canal treatment 788 791 4 06/13/23 20230701 NES 230701 INTRODUCTION Scientific terminology is an essential tool of communication as it plays a critical role in the understanding of scientific and technical terms and their associated definitions (Sageder, [34]). [Extracted from the article]

Background: Once the chemo-mechanical preparation of root canals is finished, achieving a complete seal of the root canal system becomes crucial in determining the long-term success of endodontic treatment. The important goals of root canal obturation are to minimize leakage and achieve an adequate seal. Thus, a material that possesses satisfactory mechanical characteristics, is biocompatible, and has the ability to penetrate the dentine tubules adequately is needed. Aim: This study aimed to compare the penetrability and bond strength between two calcium silicate-based sealers and an epoxy resin-based sealer, as well as examine the relationship between penetrability and bond strength for the different sealers. Method and materials: Thirty-nine recently extracted single-rooted human premolar teeth were instrumented and divided evenly into three groups (n = 13), according to the sealer used for obturation: AH Plus Jet, EndoSequence, and AH Plus Bioceramic Sealer. Three teeth (30 slices) were randomly selected out of each for analysis using confocal laser scanning microscopy to assess penetrability. The remaining ten teeth (90 slices) in each group were subject to push-out tests using a universal testing machine. All teeth were sectioned into nine transverse slices of 0.9 mm thickness for their respective tests (apical, middle, coronal). Results: AH Plus Jet exhibited significantly lower penetrability and significantly higher bond strength compared to EndoSequence BC sealer (p = 0.002) and AH Plus Bioceramic Sealer (p = 0.006). There was no significant difference between EndoSequence BC sealer and AH Plus Bioceramic Sealer in terms of either penetrability or bond strength. No correlation was found between penetrability and bond strength. Conclusions: Within the limitation of this study and regardless of the location in the canal, the bioceramic based root canal sealers appeared to perform better than the epoxy resin-based sealer in terms of dentinal penetration rate. Further studies are required to compare other biomechanical properties of bioceramic sealers including setting characteristics and bacterial leakage. [ABSTRACT FROM AUTHOR]

Background: To evaluate the cyclic fatigue resistance of rotary endodontic nickel-titanium instruments using both experimental and finite element methods. Methodology: Four different proprietary rotary endodontic instruments (PTG, PTU, VB, and TRN) were subjected to cyclic fatigue tests through a custom-built fixture (n = 30 for each group) and tested until failure according to the manufacturer's recommended settings, and the number of cycles to failure (NCF) was measured. Separated fragments were measured to determine the location of the fracture event. Finite element modeling replicated this experiment in silico via a two-step method, modeling the dynamic motion via an initial insertion step, then followed by rotation. Results: TRN showed the highest NCF (2027.94 ± 452.50) with the lowest values for strain (4.49% ± 0.23%) and fragment lengths (3.26 mm ± 0.47 mm), whereas PTU showed the lowest NCF (600.90 ± 80.86) and highest values for strain (6.29% ± 0.47%) and fragment lengths (5.36 mm ± 0.79 mm). All instruments showed an increase in von Mises and maximum principal stress during the insertion step but showed no changes to the maximum stress values during the rotational step. Conclusions: The finite element analysis approach used provided useful insights into the stress evolution and stress distribution of instruments during cyclic fatigue but lacked the ability with existing inputs to predict failure from cyclic fatigue. [ABSTRACT FROM AUTHOR]

This narrative review will focus on the evolution, present and future of engine‐driven root canal preparation. Root canal preparation changed drastically when Walia in 1988 introduced the use of nickel‐titanium (NiTi) alloys in Endodontics. In 2013, five generations of NiTi endodontic instruments had been established based on their metallurgical, mechanical properties and design features. Since then, manufacturers have been introducing further major changes in instrument design and characteristics that have not been translated in new recognized generations of instruments. In general, those changes have demonstrated enhanced instrument properties, but it is not clear yet if all those improvements are directly translated to an improvement in clinical success. This narrative review attempts to address the present status of engine‐driven instruments in terms of both evidence from laboratory‐based studies and clinical data, to identify potential further generations of instruments, and last to anticipate future directions for research and development. [ABSTRACT FROM AUTHOR]

Finite element analysis has been a valuable research tool for rotary nickel‐titanium endodontic files over the last two decades. This review aims to summarise and critique the methodology as used in currently available endodontic literature for finite element analysis of rotary nickel‐titanium instruments. An electronic literature research in PubMed and Scopus databases was performed using the appropriate search terms, and the titles and abstracts were screened for relevance. The review revealed an inconsistent approach to the finite element method, particularly with regards to the boundary conditions in which the instruments are tested. Moreover, there is a lack of experimental data to validate in silico findings. A standardised protocol to finite element analysis of rotary endodontic instruments could be considered for future studies. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this prospective quantitative study was to assess the improvement of skills among pre-clinical dental students who practiced root canal obturation on a 3D-printed tooth model. Methods: Preclinical students at the dental school (n=145) enrolled in the 2-week endodontic rotation course were invited to participate in the study. Four alphabetically distributed intact groups of first-year students were randomly allocated to either the control or the experimental group that obturated canals of a 3Dprinted tooth. The plastic model was obtained from a microCT scan and based on an STL data set. The model was an identical replica of a natural mandibular molar that had been instrumented, ready for obturation. The control group did not obturate the tooth model but received identical instruction. Later in the course all students obturated an extracted human mandibular molar tooth. Technical obturation quality was assessed by two blinded evaluators. Radiographs were used to evaluate obturation length and density. Inter-observer reliability of average performance scores was calculated with the intra-class correlation coefficient for both consistency and absolute agreement. Obturation skills of those who practiced with the model were statistically compared to students who did not use the model with the Mann-Whitney U-test. Results: Inter-observer reliability was very high for both consistency and absolute agreement. No significant differences were found in obturation skills between the experimental and control group (P>0.05). Conclusion: Under the condition of this study, dental students' obturation skills did not significantly improve by further practicing obturation using a 3D-printed model. [ABSTRACT FROM AUTHOR]

Guidance to authors is needed to prevent their waste of talent, time and resources in writing manuscripts that will never be published in the highest‐quality journals. Laboratory studies are probably the most common type of endodontic research projects because they make up the majority of manuscripts submitted for publication. Unfortunately, most of these manuscripts fail the peer‐review process, primarily due to critical flaws in the reporting of the methods and results. Here, in order to guide authors, the Preferred Reporting Items for study Designs in Endodontology (PRIDE) team developed new reporting guidelines for laboratory‐based studies: the Preferred Reporting Items for Laboratory studies in Endodontology (PRILE) 2021 guidelines. The PRILE 2021 guidelines were developed exclusively for the area of Endodontology by integrating and adapting the modified CONSORT checklist of items for reporting in vitro studies of dental materials and the Clinical and Laboratory Images in Publications (CLIP) principles. The process of developing the PRILE 2021 guidelines followed the recommendations of the Guidance for Developers of Health Research Reporting Guidelines. The aim of the current document is to provide authors with an explanation for each of the items in the PRILE 2021 checklist and flowchart with examples from the literature, and to provide advice from peer‐reviewers and editors about how to solve each problem in manuscripts prior to their peer‐review. The Preferred Reporting Items for study Designs in Endodontology (PRIDE) website (http://pride‐endodonticguidelines.org/prile/) provides a link to the PRILE 2021 explanation and elaboration document as well as to the checklist and flowchart. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate current trends in access cavity design and cleaning and shaping among endodontists. A survey was e‐mailed to active members of the American Association of Endodontists. Data showed that most respondents used traditional (57%) or conservative (43%) access cavities; less than 1% reported using ultraconservative access cavities. A glide path was created by 93% of respondents; NaOCl was used as lubricant by 51% of respondents, while 28% used RC Prep, 9% used liquid EDTA, 7% used Glyde, and 2% did not use any lubricant. Most respondents used NaOCl at 5.25% or higher concentration. Smear layer was removed by 92% of endodontists. Apical gauging was mostly accomplished with hand files. Clinical preferences varied among surveyed endodontists and among different age groups. Currently, very few endodontists use ultraconservative access preparations. There was large variation among the respondents suggesting a possible need for quality guidelines. [ABSTRACT FROM AUTHOR]

The aim of this study was to describe the mechanical properties both in stationary and dynamic conditions in vitro of the novel TruNatomy (TN; (Dentsply Sirona, Ballaigues, Switzerland) shaping files and compare them with a conventional rotary system, ProTaper Next (PTN, Dentsply Sirona). Different sizes of 2 types of rotary files, TN and PTN, were compared for their fatigue limit (n = 20 each size) and torsional resistance (n = 6 each size) and subjected to simulated shaping (n = 6 each size). Fatigue limits were determined in a novel fixture including a tapered simulated curved canal (angle = 75°, radius = 5 mm) with a thermal probe and a cooling airstream (minimum of 2 bars) attached to keep the temperature rise below 2°C. Torsional resistance was tested according to ISO 3630-1. Shaping was simulated in plastic blocks with standardized J-shaped curved root canals in a computer-controlled device to register real-time torque and force. Fracture patterns were assessed using scanning electron microscopy. Parametric statistics and Weibull analysis were used to compare groups. The tested sizes for TN were significantly more fatigue resistant and reliable compared with PTN; torsional limits were similar, but twist angles at failure were larger for TN. No instruments fractured during simulated shaping, and the working torque and the threading-in force were significantly lower for TN. This study showed the mechanical properties of both TN and PTN in terms of fatigue limit and torsional resistance and compared them with simulated canal shaping. TN was found to be more fatigue resistant and showed significantly more predicable torque and threading-in force compared with PTN. [ABSTRACT FROM AUTHOR]

Nowhere in the consideration of dental care involving endodontics does a patient become more vulnerable to potentially life-changing injuries than during a root canal procedure on the mandibular dentition that may invade and injure the neurovascular anatomy. The authors present a series of 5 cases wherein using calcium hydroxide as a disinfection strategy in endodontics caused serious neurologic injury to the treated patients. The mechanism in all cases was the inappropriate use of needle applications resulting in significant overfill into the inferior alveolar nerve space. Although calcium hydroxide has been recognized and used as a meaningful disinfectant in endodontic therapy for many years, the dangers and risks associated with a needle delivery technique are discussed and analyzed with recommendations based on current research to minimize risk. A literature search revealed that the 5 cases are not solitary cases; indeed, consequences of calcium hydroxide overfills have been described before. Therefore, a clinician initiating root canal therapy on a mandibular posterior tooth should always be mindful of the vital neurovascular anatomy, which commonly approximates the ends of these roots. Preoperative cone-beam computed tomographic imaging and the thoughtful delivery of medicaments in treatment can help the clinician manage close proximity to neural anatomy and avoid potential injuries. [ABSTRACT FROM AUTHOR]

Prior to root canal therapy, the pulp chamber needs to be accessed to allow mechanical preparation and chemical disinfection of the root canal system. An optimised access facilitates safe and effective endodontic therapy; however, errors during access, in particular over-preparation and under-preparation, may cause problems in subsequent procedures. Detailed understanding of normal anatomy and its variations is imperative and needs to be supplemented with a thorough analysis of the particular case being treated. Odontogenesis and the deposition of tertiary dentine play an important role in determining the location and extent of the penetration into the pulp chamber, as well as the location and trajectory of the coronal root canal portion. High- and slow-speed handpieces with a set of burs along with dedicated hand instruments have been used for endodontic access for decades. More recently, the increasingly widespread addition of the operating microscope and ultrasonically powered instruments has improved the chances of locating orifices, removing mineralisation and optimising access cavities. Locating all present orifices is crucial to the preparation of all canals, and straight-line access, including removal of restrictive coronal dentine and shaping of the coronal third of the root canal, is important for the successful use of nickeltitanium rotary instruments. This review presents the knowledge base and clinical guidelines for safe and efficient access cavity preparation. [ABSTRACT FROM AUTHOR]

Objectives: Retrospective description of the 10-year success rate of endodontic treatments with Thermafil (TF). Materials and methods: Patients treated by postgraduate students in an Endodontics Master's Program (2006–2008) were enrolled. All treated root canals were filled with TF and AH Plus. Teeth satisfying the inclusion criteria (206 teeth in 89 patients) were reexamined clinically and radiographically to estimate a 10-year survival and periapical health. Demographic and medical data were registered; collected information included pre-, intra-, and postoperative variables. Teeth were classified as "healthy" (PAI ≤ 2 in absence of signs/symptoms), "endodontically diseased" (presenting at least one of the following: PAI ≥ 3, signs/symptoms, retreated in the course of the follow-up, or extracted for endodontic reasons), or "non-endodontically diseased" (extracted for non-restorable fractures or periodontal disease). For teeth lost during the 10-year follow-up, details and reason of extraction were analyzed. Two PAI-calibrated examiners assessed outcomes blinded to preoperative status. Bivariate and multilevel analyses were performed (α level set at 0.05). Results: At 10 years, 179 (87%) teeth survived and 27 were extracted: 20 for non-endodontic reasons (excluded from success analysis) and 7 for endodontic reasons (considered "endodontically diseased"). Multilevel analysis revealed that the probability of extraction was increased by the presence of preoperative pain (odds ratio = 6.720; 95% confidence interval, 1.483–30.448) and by maxillary location (odds ratio = 2.950; 95% confidence interval, 1.043–8.347). Concerning periapical status, 159/186 teeth (85%) were assessed as "healthy." Multilevel analysis confirmed that maxillary location (odds ratio = 3.908; 95% confidence interval, 1.370–11.146), presence of flare up (odds ratio = 9.914; 95% confidence interval, 2.388–41.163), and fracture occurrence (odds ratio = 35.412; 95% confidence interval, 3.366–372.555) decreased the odds of healing, respectively. Conclusions: After 10 years, teeth filled with Thermafil in a specialist master's program presented a survival and a periapical health comparable to cohorts where root canals were filled with other obturation techniques. Clinical relevance: Carrier-based techniques provide time savings for clinicians while satisfying clinical quality criteria for the root filling and consequently the clinical outcome. [ABSTRACT FROM AUTHOR]

A comparison of the preparation ability of two root canal instrumentation systems in oval‐shaped canals using micro‐computed tomography was undertaken. Thirty extracted, single‐rooted, human mandibular premolars with radiographically similar canal morphology were selected, allocated to two groups (N = 15) and prepared with TRUShape or Vortex Blue (VB). Each sample was subjected to three scans (20 μm resolution): pre‐preparation and after preparation to sizes #30 and #40. Three‐dimensional data sets were evaluated for canal volume, surface area and surface treatment. Matched axial slices in apical, middle and coronal root thirds were evaluated for cross‐sectional area, roundness and transportation. Preparation with both instruments increased canal volumes and surface areas similarly and significantly (P < 0.001) with no significant difference between groups. TRUShape significantly enhanced surface treatment at both apical sizes (P < 0.05). Transportation exceeded 100 μm in only eight out of 90 cross sections. Both instruments performed similarly during preparation. TRUShape, however, significantly enhanced surface treatment. [ABSTRACT FROM AUTHOR]

Introduction Reports comparing clinical outcomes using nickel-titanium (NiTi) reciprocating instruments with other instrumentation modalities are scarce. This study examined initial shaping outcomes after an instrumentation change of root canal instrumentation technique in a doctor of dental surgery educational program. Student characteristics, faculty/student ratio, facility, and overall endodontic treatment guidelines remained unchanged. Methods A total of 200 nonsurgical initial molar root canal treatments completed by third-year dental students were evaluated. The cases were examined regarding the number of treatment appointments, access cavity preparation, canal taper, canal transportation, perforations, missed canals, presence of ledges, fractured instruments, obturation length, obturation quality, and sealer extrusion. Two independent evaluators determined the number of appointments per case; 4 independent and blinded evaluators analyzed radiographs at 4 treatment stages: preoperative situation, working length, cone fit, and obturation. Results The following factors were significantly different between the 2 cohorts: the number of appointments, preparation length, taper, and occurrence of ledges. The WaveOne (Dentsply Sirona, York, PA) cohort had a significantly reduced treatment time compared with hand/GT rotary instrumentation (Dentsply Tulsa Dental, Tulsa, OK) (average of 3.3 vs 4.3 appointments). Appropriate length control and adequate taper were significantly more frequent in the WaveOne group. The frequency of ledges was significantly larger in the hybrid group. Other variables, such as access cavity preparation, canal transportation, perforations, missed canals, fractured instruments, obturation quality, and sealer extrusion, were statistically similar between the 2 groups. Conclusions NiTi reciprocation instrumentation was superior to hybrid hand/NiTi rotary instrumentation in reducing both patient appointments and the incidence of ledging and in improving obturation length and taper in a dental student clinic setting. [ABSTRACT FROM AUTHOR]

The introduction of automated instrumentation in endodontics represented a major advance in progress for this specialty, with improvements in the quality and predictability of root canal preparation and a significant reduction in procedural errors. In recent years, endodontic instruments have undergone a series of changes brought about by modifications in design, surface treatments, and thermal treatments. In addition, new movements have also been incorporated to offer greater safety and efficiency, optimizing the properties of the NiTi alloy, especially through eccentric rotary motion. An understanding of the mechanical properties of these new NiTi instruments and their effect on the clinical performance of root canal preparation is essential if dental practitioners are to select the instruments that provide optimal clinical outcomes, especially in curved or flattened canals. The objective of this literature review is to present and discuss the characteristics of the NiTi alloys used in the major instrumentation systems available in the market, as well as the influence of the metallurgical and mechanical properties of NiTi instruments and the movements that drive them, to enable more accurate and predictable planning of root canal preparation. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate and compare, via finite element analysis (FEA), the effects of endodontic access and canal preparation on stress distribution under functional loading of a mandibular molar treated with novel (TRUShape) and conventional (Vortex) rotary root canal preparation instruments. Identical plastic mandibular molars with natural anatomy had all 4 canals shaped with either TRUShape or a conventional rotary, Vortex (#20 and #30, both by Dentsply Tulsa Dental). Finite element analysis was used to evaluate stress distribution in untreated and treated models. Micro-computed tomography (MCT) of the extracted teeth shaped in vitro was used to inform the FEA model regarding the geometry of root canals and external surfaces. Modeling the intact periodontal support and cancellous/cortical bone was based on anatomical data. Profiles of average and maximum von Mises stresses in dentin of the four treated conditions under functional loading were compared to the untreated model. This comparison was performed for each tooth model with and without root canal obturation and composite restoration. On average, the dentin sections with the most changes after preparation were located in the access cavity, with average stress increase up to +5.7, +8.5, +8.9, and +10.2 % for the TRUShape #20, Vortex #20, TRUShape #30 and Vortex #30, respectively, relative to the untreated model. Within the root canal system, the average stress differences were smaller than <5 % with lower values for TRUShape preparation. A reduction of the average stress in the access cavity was observed as an effect of the composite restoration, while about the same von Mises stress' profiles were found into the root canal. In this finite element analysis, preparation of the access cavity resulted in increased von Mises stresses under functional occlusal load. The limited (up to 0.7 %) retained radicular dentin in the TRUShape versus the Vortex cavity proved effective in reducing masticatory stresses. The bonded restoration modeled in this study only partially counterbalance the combined effects of access cavity and root canal preparation. [ABSTRACT FROM AUTHOR]

Contemporary endodontics has seen an unprecedented advance in technology and materials. This article aimed to review some of the challenges and advances in the following sections: (1) endodontic imaging, (2) root canal preparation, (3) root canal disinfection, (4) root canal filling, and (4) regenerative endodontic procedures (REPs). Jointly, these advances are aimed at improving the state of the art and science of root canal treatment. [ABSTRACT FROM AUTHOR]

The aim of this prospective quantitative study was to compare the effect of different instructional formats on dental students' skills and knowledge acquisition for access cavity preparation. All first-year dental students were invited to participate in this study conducted during the four consecutive two-week endodontic rotation courses at the University of the Pacific Arthur A. Dugoni School of Dentistry in spring semester 2015. Four alphabetically distributed intact groups of students were randomly allocated to two groups (n=70 each) that participated in either small-group discussion or a traditional lecture on access preparation. The first outcome measure was skill acquisition, measured by the quality of access cavities prepared in extracted teeth at the conclusion of the session. Two blinded raters scored direct observations on a continuous scale. Knowledge, the second outcome measure, was scored with a multiple-choice and open-ended question test at the end of each two-week session. Data were obtained for 134 of the 140 students, for a 96% response rate. The results showed that students in the small-group discussion groups scored significantly higher than those in the lecture groups when skill performance was tested (p=8.9 × 10(-7)). However, no significant differences were found in the acquisition of knowledge between the two groups on the written test. Active student participation was significantly related to improved manual skill acquisition, but the format of the session does not seem to have had a direct influence on acquired knowledge. [ABSTRACT FROM AUTHOR]

Introduction A novel S-shaped rotary file was developed to conform to nonround canal cross sections. However, the instrument should also perform well in small curved canals. This study used micro–computed tomographic scans to test the effects of TRUShape (Dentsply Tulsa Dental Specialties, Tulsa, OK) and a conventional rotary on canal geometry. Methods Twenty mandibular molars with independent mesial canals were submitted to preoperative micro–computed tomographic scans (20-μm resolution). Canals were randomly allocated to 2 groups using Vortex (Dentsply Tulsa Dental Specialties) and TRUShape for shaping according to the directions for use. Scans were obtained after size 20/.06 and 30/.06; the following outcome variables were calculated: dentin volume, smallest radicular wall thickness, treated canal surface, canal transportation, and accumulated hard tissue debris. The number of preparation errors was tabulated; data were statistically contrasted using repeated measures and factorial analyses of variance. Results The initial canal sizes were similar in both groups. Both instruments promoted preparation with no overt procedural errors. Vortex removed significantly more dentin both at size #20 and #30 ( P < .02). Significantly ( P < .02) more radicular wall dentin remained toward the furcation in the TRUShape group (1.02 ± 0.25 mm vs 0.94 ± 0.22 mm). The untreated surface at size #20 was 28.5 ± 13.9 and 19.4 ± 8.9 ( P < .05), and it was 15.1 ± 8.5 and 11.3 ± 4.9 ( P > .05) at size #30 for TRUShape and Vortex, respectively. Canal transportation at size #30 varied between 85 ± 57 μm and 179 ± 65 μm; the overall transportation scores were significantly lower for TRUShape ( P < .05). Conclusions TRUShape provided conservation of dentin by limiting dentin removal and in the absence of substantial canal transportation. In the present study, the use of TRUShape in the mesial canals of mandibular molars did not result in decreased amounts of unprepared canal surface. [ABSTRACT FROM AUTHOR]

Background. In 2010, one of the authors proposed that lasers could be used to enhance the decontaminating action of sodium hypochlorite (NaOCl). The authors conducted a study to compare the disinfection efficacy of laser-activated irrigation (LAI) by using a photon-induced photoacoustic streaming (PIPS) tip with conventional irrigation and specifically LAI’s ability to remove bacterial film formed on root canal walls. Methods. The authors shaped 26 human anterior teeth to a master apical file size of International Organization for Standardization 25/06 (size 25 tip and size .06 taper) and then sterilized the teeth, infected them with Enterococcus faecalis and incubated them for four weeks. The authors used two irrigation protocols. Group A received two cycles of 30 seconds each of 5 percent NaOCl laser activation and one cycle of 30 seconds with laser activation involving the use of 17 percent ethylenediaminetetraacetic acid (EDTA). The erbiurm:yttrium-aluminumgarnet (Er:YAG) laser’s settings were 20 millijoules, 15 hertz, 50-microsecond pulse duration, and it had a 600-micrometer PIPS tip. Group B received two cycles of 30 seconds each of 5 percent NaOCl and 17 percent EDTA irrigation alone, delivered via a syringe with a 25-gauge needle. Results. The authors found that group A had significantly better disinfection compared with group B (P < .05). The results of cultures obtained after 48 hours showed that disinfection was maintained better in group A compared with group B (P < .0001). Scanning electron microscopic images showed absence of bacterial biofilm remaining after LAI using PIPS. Conclusions. Er:YAG laser activation of 5 percent NaOCl and 17 percent EDTA was more effective than conventional irrigation for eradicating E. faecalis and preventing new bacterial growth ex vivo. Additional clinical studies are needed to clarify the effect on endodontic treatment outcomes.Practical Implications. PIPS appears to be effective in enhancing the effect of the irrigants commonly used in endodontics. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: The purpose of this pilot study in a cadaver model was to compare 2 different shaping techniques regarding the induction of dentinal microcracks. Methods: Three lower incisors from each of 6 adult human cadaver skulls were randomly distributed into 3 groups: the control group (CG, no instrumentation), the GT group (GT Profile hand files; Dentsply Tulsa Dental, Tulsa, OK), and the WO group (WaveOne; Dentsply Tulsa Dental). In the GT group, manual shaping in a crown-down sequence with GT Profile hand files was performed. In the WO group, Primary WaveOne files were used to the working length. Teeth were separated from the mandibles by careful removal of soft tissue and bone under magnification. Roots were sectioned horizontally at 3, 6, and 9 mm from the apex using a low-speed saw. Color photographs at 2 magnifications (25× and 40×) were obtained. Three blinded examiners registered the presence of microcracks (yes/no), extension (incomplete/complete), direction (buccolingual/mesiodistal), and location. Data were analyzed with chi-square tests at P < .05. Results: Microcracks were found in 50% (CG and GT) and 66% (WO) of teeth at 3 mm, 16.6% (CG) and 33.3% (GT and WO) at 6 mm, and 16.6% in all 3 groups at 9 mm from the apex. There were no significant differences in the incidence of microcracks between all groups at 3 (P = .8), 6 (P = .8), or 9 mm (P = 1). All microcracks were incomplete, started at the pulpal wall, and had a buccolingual direction. Conclusions: Within the limitations of this pilot study, a relationship between the shaping techniques (GT hand and WaveOne) and the incidence of microcracks could not be shown compared with uninstrumented controls. [Copyright &y& Elsevier]

Abstract: Introduction: The purpose of this study was to compare peak torque and force between ProTaper Universal (PTU) and ProTaper Next (PTN) instruments during the preparation of large and small root canals in extracted teeth. Methods: Twelve maxillary incisors and each independent canal of 6 mesial roots of mandibular molars were randomly assigned to be prepared with a new set of either PTU or PTN instruments after a glide path was achieved. A total of 12 new sets of each instrument system were used. The tests were run in a standardized fashion in a torque-testing platform. Peak torques (Ncm) and force (N) were registered; analysis of variance and Tukey post hoc tests were then applied. Results: Among instruments in the same sequence, no significant differences in peak torque and force were found among PTN instruments when shaping small or large root canals, but some PTU instruments showed statistically lower peak torque and force (P < .01) than others for both types of canals. Whereas PTU instruments showed significant differences in peak torque and force (P < .05) between large and small root canals, PTN instruments showed significantly lower force (P < .04) in large canals, but peak torque was not significantly different for upper central incisors or mesial mandibular root canals. Conclusions: Under the conditions of this study, instruments in ProTaper Next set showed greater regularity in peak torque for small and large canals than ProTaper Universal instruments. [Copyright &y& Elsevier]

Abstract: Introduction: The purpose of this study was to assess torque and force for simulated canal preparation with a new root canal instrument, ProTaper Next. Methods: Six sets of ProTaper Next Instruments (X1–X5) were used to prepare 36 artificial canals. Files were divided into 6 groups. Different settings of rotations per minute (250, 300, and 350 rpm) and numbers of in-and-out movements to reach working length (3 or 4 insertions [ins]) were applied in each group (250 rpm/3 ins, 250 rpm/4 ins, 300 rpm/3 ins, 300 rpm/4 ins, 350 rpm/3 ins, and 350 rpm/4 ins) by using an automated torque bench. Peak torques (Ncm) as well as positive and negative forces (N) were registered. Analysis of variance and Tukey post hoc tests were applied. Preliminary data for angle and stationary torque at failure were also obtained and compared with peak torque for each instrument. Results: Significant differences in peak torque (P < .0001), positive force (P < .002), and negative force (P < .0001) were found for ProTaper Next instruments overall. X2 showed the highest torque with all settings. X5 showed the highest positive force in all groups. X1 and X2 showed the highest negative forces for all groups except for 350 rpm/4 ins. Significantly lower torque (P < .0001) and positive force (P < .007) were measured in the group 350 rpm/4 ins for all instruments except for X4. In contrast, X1 showed a significantly lower negative force for 350 rpm/4 ins. Torque at failure according to American Dental Association no. 28/ISO 36030-1 was lower for X1, X2, and X3 than torque during simulated canal preparation (P < .0001). Conclusions: Under the conditions of this study, using ProTaper Next at 350 rpm and with 4 in-and-out movements resulted in lowest levels of peak torque as well as positive and negative forces. [Copyright &y& Elsevier]

Objectives: The purpose of this study was to evaluate the prevalence of three-rooted permanent mandibular first molars (PMFMs) with four canals and their morphological characteristics among a Korean population from using cone-beam computed tomography scans (CBCTs). Materials and methods: Among the 705 CBCTs screened, 472 patient cases possessing at least one PMFM were identified. A total of 780 PMFMs were evaluated in axial section series to determine the number of roots and canals. The incidences of three-rooted PMFMs were compared with regard to gender and location. For distal root(s) with two canals, inter-orifice distances (IOD) between distobuccal and distolingual canals were measured at pulpal floor and furcation levels. The difference of IOD between males and females was also analyzed using chi-square tests. Results: Among the 472 CBCTs of 225 females and 247 males, 84 females and 107 males were found to have at least one three-rooted PMFM. Among the 780 PMFMs, 191 PMFMs (24.5%, 89 of 397 left and 102 of 383 right) were found to have three roots. The prevalence of distal root(s) with two canals was 34.2% (267 of 780). From the molars with two distal canals, the mean IOD between distobuccal and distolingual canals at the pulpal floor level was 3.1 mm in males and 2.9 mm in females ( p = 0.0428). Conclusions: The occurrence of three-rooted PMFMs among a Korean population was 24.5% and was higher than other countries and ethnicities. Understanding the prevalence of PMFMs with a distolingual root and/or canal in a Korean population and the IOD between distobuccal and distolingual canals may be useful for successful endodontic treatments. Clinical relevance: Acknowledgment of potential incidence of three-rooted permanent mandibular first molars with four canals and the distance between two distal canals may increase the success rate of root canal treatment by reducing the missing canal untreated. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: Although it is apparent that teeth become more susceptible to fracture after root canal treatment, the contributing factors for this are not completely established. The purpose of this study was to determine whether there are changes in nanomechanical properties of dentin in root canal–treated teeth compared with non–root canal–treated control teeth. Methods: Atomic force microscopy–based nanoindentation testing was performed on root canal–treated teeth and age- and type-matched control teeth. Radicular intertubular dentin was indented in 6 locations, and triplicate measurements were averaged. Paired t tests were used to compare root canal–treated teeth with control teeth. Results: The moduli of elasticity were 17.8 ± 2.9 GPa and 18.9 ± 2.9 GPa for root canal–treated teeth and controls, respectively; the hardness values for the 2 groups were 0.84 ± 0.25 GPa and 0.84 ± 0.18 GPa, respectively. Neither the modulus of elasticity nor the hardness differed between groups (P > .05). Conclusions: It appears that root canal treatment does not result in nanomechanical changes to radicular intertubular dentin. [Copyright &y& Elsevier]

Abstract: Introduction: This study set out to compare the efficacy of laser-activated and ultrasonically activated root canal disinfection with conventional irrigation, specifically its ability to remove bacterial film formed on root canal walls. Methods: Seventy human premolars were shaped to an apical size #20, taper .07, sterilized, and contaminated in situ with oral bacteria for 1 week and incubated for 2 more weeks. Irrigation was done with 6% NaOCl (group 1), NaOCl ultrasonically activated with blunt inserts (group 2), or a pulsed erbium:YAG laser at nonablative settings (group 3) for a total of 60 seconds each. Positive and negative controls were also included. Aerobic bacterial sampling was performed, and the incidence of positive samples after 24 and 48 hours as well as bacterial counts (colony-forming units) were determined. Fixed and demineralized sections 1 mm and 4 mm off the apex were Brown-Brenn stained and assessed for remaining intracanal bacteria/biofilm and dentinal tubule penetration. Results: All 3 canal disinfection protocols significantly reduced bacterial counts (P < .001). None of the 3 techniques predictably generated negative samples, but laser-activated disinfection was superior to the other 2 techniques in this aspect (P < .05). Histologic sections showed variable remaining bacterial presence in dentinal tubules at the 4-mm level and significantly less bacterial biofilm/necrotic tissue remaining at the 1-mm level after laser-activated irrigation (P < .05). Conclusions: Under the conditions of this combined in situ/in vitro study, activated disinfection did not completely remove bacteria from the apical root canal third and infected dentinal tubules. However, the fact that laser activation generated more negative bacterial samples and left less apical bacteria/biofilm than ultrasonic activation warrants further investigation. [Copyright &y& Elsevier]

Abstract: Introduction: Both the number of rotations in curved canals and torque are related to fracture resistance of nickel-titanium rotaries via the respective mechanisms of brittle and flexural failure. Increased rotational speed (rotations per minute [RPM]) may lead to higher cutting ability and could overcompensate for increased fatigue. The impact of three RPM settings on peak torque (Nmm) and apically directed force (N) during root canal preparation were investigated in vitro. Methods: S-shaped canals in plastic blocks (n = 12/group) were instrumented with Vortex rotaries (Dentsply Tulsa Dental, Tulsa, OK) sizes #15 to 30 with a .04 taper. Rotaries were used in a manufacturer-recommended sequence: #30, 25, and 20 in a crown-down approach progressively deeper into the canal, #15 to the working length, and apical enlargement with sizes 20 and 25 to WL. A total of 216 preparation procedures were performed using a custom testing platform. RPM was set at 200, 400, or 600; automated axial feed mirrored clinical handling, resulting in two in-and-out movements, each to preset insertion depths. Torque and apical force were continuously recorded and peak values statistically contrasted using analysis of variances. Results: No file fractures were observed in any of the three experimental groups. Peak torques and forces varied by instrument size and were highest at 200 RPM for all sizes; torque and force were reduced by 32% and 48%, respectively, at 400 RPM (P < .001). Increasing RPM to 600 did not result in further reductions. The number of discernible peaks for torque (threshold: 0.3 Nmm) and force (threshold: 0.2 N) significantly decreased from 200 RPM to 400 RPM and did not decrease further with 600 RPM. Conclusions: Under the present experimental conditions, rotational speed had a significant impact on preparation with Vortex rotaries, with instruments at 400 RPM generating less torque and force compared with 200 RPM. [Copyright &y& Elsevier]

Abstract: Introduction: The aim of this study was to describe the canal shaping properties of a novel nickel-titanium instrument, the self-adjusting file (SAF), in maxillary molars. Methods: Twenty maxillary molars were scanned by using micro–computed tomography at 20-μm resolution. Canals were shaped with the SAF, which was operated with continuous irrigation in a handpiece that provided an in-and-out vibrating movement. Changes in canal volumes, surface areas, and cross-sectional geometry were compared with preoperative values. Canal transportation and the fraction of unprepared canal surface area were also determined. Data were normally distributed and compared by analyses of variance. Results: Preoperatively, mean canal volumes were 2.88 ± 1.32, 1.50 ± 0.99, and 4.30 ± 1.89 mm3 for mesiobuccal (MB), distobuccal (DB), and palatal (P) canals, respectively; these values were statistically similar to earlier studies with the same protocol. Volumes and surface areas increased significantly in MB, DB, and P canals; mean canal transportation scores in the apical and middle root canal thirds ranged between 31 and 89 μm. Mean unprepared surfaces were 25.8% ± 12.4%, 22.1% ±12.0%, and 25.2% ± 11.3% in MB, DB, and P canals, respectively (P > .05) when assessed at high resolution. Conclusions: By using SAF instruments in vitro, canals in maxillary molars were homogenously and circumferentially prepared with little canal transportation. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: This study evaluated the prepared surface areas of oval-shaped canals in distal roots of mandibular molars using four different instrumentation techniques. Methods: Teeth were prescanned and reconstructed using micro–computed tomography (MCT) scans at low resolution (68 μm). Forty-eight molars with ribbon-shaped/oval distal root canals were selected and randomly assigned to four groups. Distal canals (n = 12 each) were prepared by circumferential filing using Hedström files to apical size #40 (group H/CF); with ProTaper nickel-titanium rotaries to finishing file 4 (F4) considering the distal canal as 1 canal (group PT/1); ProTaper to F4 considering buccal and oral aspects of the distal canal as 2 individual canals (group PT/2); ProTaper to F4 in a circumferential filing motion (PT/CF). Before and after shaping, teeth were evaluated using MCT at 34-μm resolution. The percentage of prepared surface was assessed for the full canal length and the apical 4 mm. Statistical analysis was performed using analysis of variance and Bonferroni/Dunn multiple comparisons. Results: Preoperatively, canal anatomy was statistically similar among the groups (p = 0.56). Mean (± standard deviation) untreated areas ranged from 59.6% (±14.9, group PT/2) to 79.9% (±10.3, PT/1) for the total canal length and 65.2% to 74.7% for the apical canal portion, respectively. Canals in group PT/1 had greater untreated surface areas (p < 0.01) than groups PT/2 and PT/CF. Among all groups, amounts of treated surface areas were statistically similar in the apical 4 mm. Conclusions: Preparations of oval-shaped root canals in mandibular molars left a variable portion of surface area unprepared regardless of the instrumentation technique used. However, considering oval canals as two separate entities during preparation appeared to be beneficial in increasing overall prepared surface. [Copyright &y& Elsevier]

Abstract: Introduction: Previous micro–computed tomography analyses of root canal preparation provided data that were usually averaged over canal length. The aim of this study was to compare preparation effects on apical root canal geometry. Methods: Sixty extracted maxillary molars (180 canals) used in prior studies were reevaluated for analyses of the apical 4 mm. Teeth were scanned by using micro–computed tomography before and after canal shaping with FlexMaster, GT-Rotary, Lightspeed, ProFile, ProTaper, instruments or nickel-titanium K-files for hand instrumentation. Apical preparation was to a size #40 in mesiobuccal and distobuccal and #45 in palatal canals except for GT (#20) and ProTaper (#25 in mesiobuccal and distobuccal and #30 in palatal canals, respectively). Data for canal volume changes, the structure model index (quantifying canal cross sections), and untreated surface area were contrasted by using analysis of variance and Scheffé tests. Results: Mean mesiobuccal, distobuccal, and palatal canal volumes increased after preparation (P < .05), but differences were noted for preparation techniques. GT rendered the smallest (0.20 ± 0.14 mm3); K-files and ProFile showed the largest volume increases (0.51 ± 0.20 mm3 and 0.45 ± 021 mm3, P < .05). All canals were slightly rounder in the apical 4 mm after preparation indicated by nonsignificant increases in structure model index. Untreated areas ranged from 4%–100% and were larger in mesiobuccal and palatal canals than in distobuccal ones. Preparation with GT left significantly larger untreated areas in all canal types (P < .05); among root canal types, distobuccal canals had the least amounts of untreated surface areas. Conclusions: Apical canal geometry was affected differently by 6 preparation techniques; preparations with GT instruments to an apical size #20 left more canal surface untouched, which might affect the ability to disinfect root canals in maxillary molars. [Copyright &y& Elsevier]

Abstract: This study evaluated temperature changes during passive ultrasonic irrigation. Root canals of three extracted maxillary canines were enlarged to size #45. Thermocouples were mounted 3, 6, and 9 mm from the apical foramen. Teeth were placed in a water bath at 37°C. Distilled water (20°C) was continuously delivered through an ultrasonic unit (group 1) or deposited into the root canal before ultrasonic activation (group 2); for activation, noncutting nickel-titanium (NiTi) inserts or stainless steel K-files #15, #25, and #35 were used. Before and during ultrasonic activation, temperatures were continuously measured for 210 seconds. Statistical analysis was performed using analysis of variance and Scheffé post hoc tests. Temperatures initially decreased by up to 7.4°C; these drops were significantly smaller in group 1 than in group 2 (p < 0.001) in the middle and apical root canal third. The decreases were followed by temperature rises for all inserts in group 2. However, in group 1, temperatures just reached baseline values in middle and apical thirds; in the coronal root canal third, lower temperatures were measured. In group 2, mean temperature rises were 7.7°, 7.5°, and 4.2°C in coronal, middle, and apical root canal thirds. Here, K-file type inserts size #35 generated highest and inserts size #15 the lowest temperatures rises; NiTi inserts were more effective than size #15 K-files and less effective than #35 K-files. Continuous flow negated the potential of ultrasonic activation to heat irrigation solutions. Noncutting NiTi instruments and large K-files were more effective than small K-files in warming deposited irrigants. [Copyright &y& Elsevier]

Purpose: To describe the treatment of a patient with a dismal oral situation after successful cure for drug addiction. Methods: After root canal treatment and surgical pretreatment, four maxillary glass-fiber reinforced composite fixed partial dentures, anchored by endo-crowns instead of post and core, were fabricated (Targisj & Vectrisj). Additionally, full crowns on four dental implants and an inlay were produced of non-reinforced composite ( Taigis). All restorations were luted adhesively to abutments with a three component adhesive system (Syntac Classic), light-curing composite (Tetric) and an ultrasonic insertion technique. Results: An esthetic and functional acceptable result was achieve d. Excessive removal of tooth structure by post preparation may weaken the root. [ABSTRACT FROM AUTHOR]

The author names in the original version of this article were inadvertently interchange. Correct presentation of author names is reflected here. [ABSTRACT FROM AUTHOR]

The author reflects on the procedural mishaps and complications during root canal treatment and other endodontic therapy. He says that the technical nature of error causes biological problems that leads to the failure of the treatment. He discusses ledging, perforation on access, rotary instrument fracture, safe and effective irrigation, and vertical root fracture as factors to be considered in root canal treatment. He also mentions dentin, endodentic procedures, and longitudinal root fractures.

Pulp regeneration is a biologic process occurring under specific circumstances. An endodontic treatment modality to accomplish pulp regeneration has emerged based on the response of undifferentiated cells that are often referred to as stem cells. The treatment itself is currently empirical based on clinicians' thoughts and observations. The demonstration of a variety of dental stem cells initiated basic research detailing the properties and behavior of these cells. Attempts are made to bridge gaps in knowledge regarding treatment strategies by translating basic stem cell research into practice. However, neither the patient population likely to benefit from pulp regeneration nor most clinical parameters are well described. Classic topics in endodontics (eg, indication/clinical diagnosis, disinfection/irrigation, and root canal preparation/pretreatment) have to be revisited under the premises of pulp regeneration. Furthermore, new topics like the development of new diagnostic tools or new clinical success criteria will emerge, and the translational research itself will generate new insight into pulp regeneration mechanisms. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to assess the influence of the shaping technique on incidence, intensity, duration and type of postoperative pain (PP). Methods: Root canal treatments were carried out with rotary instrumentation (n = 80) during a single-visit, and data about pre-treatment conditions were collected. Patients were given a questionnaire to record the presence or absence of post-endodontic pain, its duration and level of discomfort. A matching patient (same pre-treatment conditions but manual instrumentation) was randomly selected from a pool (n = 374) and assigned to the control group. A total of 44 pairs of patients matched completely and were included in the study. Incidence (yes/no) of PP was assessed using Chi-square tests, intensity (mild, moderate, severe) with trend tests and duration (days) with Mann-Whitney U tests. Results: A significantly greater proportion of the patients in the control group reported pain than did patients in the rotary shaping group (p < 0.05). However, pain duration was shorter (p = 0.008) in the control group. Differences in level of discomfort were not statistically significant. Conclusions: The results of this prospective in vivo study suggest that a higher incidence of PP should be expected after manual root canal preparation. However a second major finding of the study is that when present, PP after a rotary canal preparation is expected to last longer. Clinical significance: There has been an increase in the use of rotary techniques among dentists in recent years. The present study analyses the differences in the incidence and characteristics of postoperative pain that should be expected after rotary canal preparation compared to traditional manual methods that had not been reported yet. [ABSTRACT FROM AUTHOR]