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

The Outcomes of Endodontically Treated Teeth Restored with Custom-Made Cast Post-and-Core Restorations: A Retrospective Cohort Study

INTRODUCTION

Custom-made cast post-and-core (CMCPC) restorations have long been used to restore structurally deficient endodontically treated teeth (ETT). However, the evidence regarding their impact on the outcomes of ETT is largely inconclusive. This study evaluated the long-term treatment outcome of ETT restored with CMCPC.

METHODS

This retrospective cohort study examined the dental records of patients that received CMCPC at a specialty private practice in Toronto, Canada between 1999 and 2021. The proportion of ETT with complete periapical healing and those that survived were estimated, and prognostic factors were investigated using multiple logistic and Cox regression analyses respectively (P < .05).

RESULTS

A total of 500 and 1000 teeth met periapical healing and survival criteria, respectively. The periapical healing rate was 88.8% and was associated with the presence of baseline periapical radiolucency [odds ratio = 0.1; 95% confidence interval (CI), 0.05-0.2; P < .001]. The survival after a median follow-up time of 52.9 months (interquartile range: 26.5-99.4) was 90.1% and was associated with <75% of root length in bone [hazard ratio (HR) = 2.6; 95% CI, 1.0-6.6; P = .033], type and quality of final restoration (HR = 2.09; 95% CI, 1.1-3.9; P = .020; HR = 2.3; 95% CI, 1.2-4.5; P = .008, respectively), and the presence of periapical radiolucency at the latest recall (HR = 3.2; 95% CI, 1.7-6.3; P < .001).

CONCLUSIONS

The outcome of ETT restored with CMCPC was favorable. CMCPC may be regarded as a viable restorative option for structurally deficient ETT.

An Experimental Anatomic CBCT Study on the Correlations Between MB1 and MB2 of the Mesio-Vestibular Root of the Upper First Molars

This experimental anatomic study aimed to investigate the correlations between the mesio-vestibular canal (MB1) and the second mesio-vestibular canal (MB2) of the mesio-vestibular root of the upper sexts using cone-beam computed tomography (CBCT) imaging. A total of 24 extracted maxillary first molars were collected and subjected to CBCT imaging. The presence, location, and morphology of MB1 and MB2 canals were evaluated using axial, coronal, and sagittal CBCT sections. The interrelation between MB1 and MB2 canals was assessed, including their separate canals, merging, and division points. Among the 24 maxillary first molars examined, 86.5% demonstrated the presence of an MB2 canal in addition to MB1. The MB2 and MB1 were confluent in 80% of the cases with a confluent height of 4,16 mm. The mean distance between MB1 and MB2 canals was 1.85 mm. This study provides detailed information on the anatomic correlations between MB1 and MB2 canals of the mesio-vestibular root in the upper sexts using CBCT imaging. The high prevalence of MB2 canals suggests their significance in endodontic procedures and emphasizes the importance of thorough exploration and identification during root canal treatment. The knowledge of the location and morphology of these canals can aid in successful endodontic therapy and enhance treatment outcomes.

Anatomical complexities affecting root canal preparation: a narrative review

A fundamental aspect of the Endodontic field is the knowledge of root canal anatomy. Using a variety of techniques, the internal and external anatomy of teeth have been extensively investigated throughout the past century. Recent improvements in three-dimensional computed tomography have enabled more detailed evaluations of root canal morphology in both clinical and laboratory settings. Essentially, researches have unveiled that the root canal constitutes a complex system, comprising not only the main root canal but also lateral components, including isthmuses, fins, accessory canals and apical ramifications. Undoubtedly, this intricate morphology poses a significant challenge when it comes to the process of shaping, cleaning and disinfecting the root canal system. This article aims to explore the anatomical aspects of the root canal system that impact the chemomechanical procedures.

A critical appraisal of research methods and experimental models for studies on root canal preparation

It is the aim of this review to present a critical overview and summary on the contemporary possibilities, limitations and challenges of research related to root canal preparation. Frequently used research tools and contemporary research designs will be presented and discussed critically focussing on shortcomings and benefits with special regard to clinical relevance and scientific evidence. A plethora of experimental set-ups for assessing the shaping of root canals have been described in the endodontic literature using a considerable number of techniques and instruments. Nevertheless, it can be stated that scientific evidence demonstrating the clinical impact of many investigated topics is questionable or even missing. Instead of technical, radiographic and geometrical parameters, further research should focus on biological aspects and clinical evidence of the impact of root canal preparation on the outcome of root canal treatment.

Heat Treatment and Surface Treatment of Nickel–Titanium Endodontic Instruments

Knowledge and thorough understanding of the characteristics of endodontic nickel–titanium (NiTi) files is paramount for dentists performing root canal treatments to patients. Understanding the behavior of the NiTi files guides the clinicians in choosing the correct instruments for different clinical and anatomical situations. This review focuses on the metallurgical properties of endodontic NiTi files, with a special emphasis on recent developments and improvements in metallurgy and the effects of heat treatment and surface treatment. In this study, the impact that such developments have on the properties of endodontic NiTi files is discussed.

Outcome of Root Canal Treatment of Necrotic Teeth with Apical Periodontitis Filled with a Bioceramic-Based Sealer

Introduction

Apical periodontitis is among the most common pathologies in endodontics. The treatment of apical periodontitis has always been an important occupation in the modern practice of endodontics, and the failure has been associated with nonhermetic root canal filling. With that in mind, bioceramic-based sealers have been incorporated into endodontic practice. The purpose of this study was to evaluate the outcome of nonsurgical root canal treatment (RCT), using a single-cone and Bioroot RCS filling of necrotic teeth with apical periodontitis.

Materials and Methods

This follow-up study included patients treated in the department of Restorative Dentistry and Endodontics in the Dental Clinic of Monastir, from January 2018 to December 2019. The study intended to include all adult patients presenting a symptomatic or asymptomatic apical periodontitis. Once the diagnosis was performed, the patients were divided into two groups: a one-session treatment group and a two-session treatment group. All cases were obtured with BioRoot using a single-cone technique with a minimum of a 6-month recall. At 6-month follow-ups, teeth were classified as healed, healing (success), or not healed (failure), based on clinical and radiographic findings.

Results

Twelve patients met the inclusion criteria, six patients per group. Seven patients returned for follow-ups. At 6-month follow-ups, the overall success rate was 100%, with 57.1% determined to be “healed” and 42.8% determined to be “healing.” All the PAI scores decreased compared to the baseline situation.

Conclusion

The results obtained showed the contribution of BioRoot RCS in the healing of periapical lesions. Accordingly, bioceramic-based sealers seem to optimize the prognosis of root canal treatments.

Comparative evaluation of dentin volume removal and centralization of the root canal after shaping with the ProTaper Universal, ProTaper Gold, and One-Curve instruments using micro-CT

Background. The main goal of our study was to assess the volume of dentin removed and transportation in root canals using ProTaper Universal (PTU), ProTaper Gold (PTG) and One-Curve (OC). Ni-Ti rotary instruments in extracted human teeth using by micro-CT.

Methods: Thirty human upper 1st premolar teeth with two separate root canals and sturdy, mature root tips were used in the present study. Specimens were decoronated and root length was standardized for micro CT scanning before root canal preparation done. The teeth were randomly separated into three categories (n = 10) according to the rotary NiTi system used for canal instrumentation, i.e., PTU (Dentsply, Maillefer), PTG (Dentsply, Maillefer), and OC (Micro-Mega SA). After root canal preparation, samples were scanned again on micro-CT by the same scanning parameters. Surface area, canal volume, structure model index (SMI), percentage of uninstrumented area and transportation parameters were obtained for each sample before and after micro-CT analyse.

Results: No significant differences between the PTG and PTU in terms of the total volume of removed dentin, surface area and percentage of uninstrumented areas were found. However, regarding to parameters above, OC showed a lower efficacy than PTG and PTU in coronal section. Regarding canal transportation, PTG and OC showed lower mean transportation values at all levels.

Conclusion: This paper demonstrated the root canal shaping abilities of the PTU, PTG, and OC NiTi file systems. The PTG and OC systems were associated less canal transportation and a better ability to preserve dentinal walls than PTU. There was no significance different between all rotary file systems for SMI values however, PTU and PTG showed greater canal volume and surface area change than OC file systems in coronal section.

Comparison of Clinical and Radiographic Success of Rotary with Manual Instrumentation Techniques in Primary Teeth: A Systematic Review

Aim and objective

A systematic review was planned to compare the clinical and radiographic success rate of pulpectomy in primary molars using a rotary system and hand files system.

Study design

The literature search was undertaken in electronic databases from January 2000 to December 2019 using keywords. Four hundred and forty-two studies were identified after applying limits. Three hundred and thirty-one irrelevant articles were eliminated. Among the 111 articles obtained, 90 articles were eliminated after reading the titles and abstracts. After assessing the full text, 18 articles were eliminated. Randomized controlled trials (RCTs) published in the English language on pulpectomy of primary molars, using hand files and rotary files and with a follow-up period of 12 months were included.

Results

Three RCTs comparing the clinical and radiographic pulpectomy success rates using rotary and hand files instrumentation were finally selected. Qualitative assessment with RoB 2.0 showed one study had a low risk of bias and two studies had a high risk of bias.

Conclusion

Pulpectomy procedures in primary teeth using rotary and hand files instrumentation techniques were equally effective in terms of success rates.

How to cite this article

Natchiyar N, Asokan S, Geetha Priya PR, et al. Comparison of Clinical and Radiographic Success of Rotary with Manual Instrumentation Techniques in Primary Teeth: A Systematic Review. Int J Clin Pediatr Dent 2021;14(1):8–13.

Endodontic Periapical Lesion: An Overview on the Etiology, Diagnosis and Current Treatment Modalities

Nonsurgical and surgical endodontic treatments have a high success rate in the treatment and prevention of apical periodontitis when carried out according to standard and accepted clinical principles. Nevertheless, endodontic periapical lesions remain in some cases, and further treatment should be considered when apical periodontitis persists. Although several treatment modalities have been proposed for endodontically treated teeth with persistent apical periodontitis, there is a need for less invasive methods with more predictable outcomes. The advantages and shortcomings of existing approaches for the diagnosis and treatment of endodontic periradicular lesions are discussed in this review.

Effect of Curvature Location on Fatigue Resistance of Five Nickel-titanium Files Determined at Body Temperature

INTRODUCTION

The purpose of this study was to evaluate the effect of 5 different curvature locations on the fatigue resistance of thermomechanically treated nickel-titanium (NiTi) files and superelastic NiTi files at body temperature and to document the corresponding phase transformations.

METHODS

EndoSequence (ES; Brasseler USA, Savannah, GA), EndoSequence CM (ESCM, Brasseler USA), K3 (SybronEndo, Orange, CA), K3XF (SybronEndo), and Vortex Blue (VB; Dentsply Tulsa Dental Specialties, Tulsa, OK) NiTi files (size 25/.04) were subjected to fatigue tests inside customized artificial canals containing a curvature of 60° and a 3-mm radius. There were 5 different canals based on the location of initial curvature; these included groups in which the distance between the canal orifice and the location of the curvature (DOC) was 5, 6, 8, 10, and 11 mm. The model canal was immersed in water at 37°C ± 1°C. The number of cycles to failure (N_f) was recorded, and the fracture surface of the fragments was examined by scanning electron microscopy. Two unused files of each brand were examined by differential scanning calorimetry.

RESULTS

The N_f was highest in the 10-mm and 11-mm DOC groups and lowest with the 5-mm and 6-mm DOC groups (P < .05). ESCM files had the highest fatigue resistance followed by the VB, K3XF, K3, and ES files (P < .05). ESCM files had the highest N_f (P < .05), and ES and K3 files had the lowest N_f (P < .05) depending on the curvature location. Two endothermic peaks were observed on the heating curve of the heat-treated files (ESCM, K3XF, and VB).

CONCLUSIONS

The location of the canal curvature had a significant effect on the fatigue resistance of both heat-treated and superelastic NiTi files. The fatigue life of files in the coronal curve was quite short.

Clinical Efficacy of Single-visit Pulpectomy over Multiple-visit Pulpectomy in Primary Teeth: A Systematic Review

Objective

The purpose of this systematic review was to compare the efficacy of single-visit pulpectomy (SVP) vs multiple-visit pulpectomy (MVP) in infected primary teeth.

Materials and methods

An extensive literature search in the English language was conducted in PICO format using MeSH terms using databases (PubMed, EBSCO, Ovid, and Cochrane) and pre-specified inclusion and exclusion criteria were applied to identify relevant studies comparing pulpectomy in single and multiple visits.

Results

Only 4 studies (3—in vivo clinical study; 1—in vivo microbial study) sustained the final analysis and were included for critical appraisal. Results of the systematic search revealed that there are only a few studies comparing the efficacy of single-visit pulpectomy vs multiple-visit pulpectomy in infected primary teeth.

Conclusion

On the basis of the available studies, evidence favors the SVP protocol over the MVP protocol. Whenever possible the single-visit protocol can be preferred over the multiple-visit protocol. The quality of evidence available is low.

How to cite this article

Tirupathi SP, Krishna N, Rajasekhar S, et al. Clinical Efficacy of Single-visit Pulpectomy over Multiple-visit Pulpectomy in Primary Teeth: A Systematic Review. Int J Clin Pediatr Dent 2019;12(5):453–459.

Spatial Cleaning Action of Ultrasonic Irrigation on Enterococcus faecalis Biofilm

This study aimed to examine the spatial cleaning effect of ultrasonic irrigation in simulated root canal with oblong cross section in the absence of antimicrobial agent. A 7-day E. faecalis biofilm was cultivated in a rectangular, simulated canal model and subjected to passive ultrasonic irrigation (PUI) with sterile saline for 5 minutes. After that, the biofilm was examined by confocal microscopy after bacterial viability staining at 58 sites around and beyond the endosonic file. Results showed that, at the vicinity of the file, the amount of viable bacteria ranged from 13.1% (2.75 mm from the tip) to 40.5% (4.5 mm level). Lesser amounts of live bacteria were observed within 1 mm from the vibrating file, which amount increased for sites farther away. At 3 mm distance, the amount of bacteria (35.5 to 64.4%) was significantly greater than areas situated close to the vibrating file (P < 0.01). Sites next to the anti-nodes of file had less bacteria remaining than sites near the nodes (P = 0.050). Apically (0.5 mm or more), the amount of bacteria was significantly greater than that at the file tip (16.4%) (P < 0.05). It was concluded that PUI is able to dislodge a single-species biofilm, provided that they are situated in close vicinity to the vibrating file.

Outcome of endodontic treatment with chlorhexidine gluconate as main irrigant: A case series

This study evaluated the overall endodontic therapy success using 0.12% or 2% chlorhexidine gluconate as main irrigant. Seventy-two teeth diagnosed as vital, necrotic or previously treated teeth with apical periodontitis that were consecutively treated by orthograde therapy. All cases were followed clinically and radiographically for at least 1-year period. Success was established in teeth without signs or adverse clinical symptoms and complete or incomplete radiographic healing. Failure was determined in teeth with any sign or adverse clinical symptoms and a new, unchanged or enlarged radiographic periapical lesion. The data were analysed using chi-square and Fischer's exact tests. The overall success rate for teeth undergoing vital pulp was 84.6%, 76.2% as for the necrotic teeth and 84% for the retreatment cases. No significant differences were observed between groups (P > 0.05). Cases treated with CHX as main irrigant showed a high overall endodontic therapy success rate.

Effectiveness of a reciprocating single file, single cone endodontic treatment approach: a randomized controlled pragmatic clinical trial

OBJECTIVES

To compare the root filling quality, the sealer extrusion, and the healing rates of apical lesions addressed via two endodontic treatment approaches. The hypothesis tested was that both techniques present similar apical periodontitis healing results.

MATERIALS AND METHODS

This study was a parallel-design, pragmatic, and randomized clinical trial. One hundred twenty anterior teeth with necrotic pulps and apical periodontitis were randomly allocated to be either instrumented with hand files and obturated with the lateral compaction technique or instrumented with a single file in a reciprocating movement and obturated with a single-cone technique. The root canal filling quality, the occurrence of sealer extrusion, and apical periodontitis healing were the outcomes of interest. Data were analyzed through chi-square analysis, and the odds ratio for healing was adjusted using a logistic regression model (α = 0.05).

RESULTS

No significant differences were observed between the endodontic techniques regarding the root filling quality or sealer extrusion. Six months after treatment, both endodontic techniques presented equivalent results regarding apical periodontitis healing. The healing rate was affected only by the periapical status at baseline.

CONCLUSIONS

The obturation of the root canal of the anterior teeth using reciprocating file-matched single cones presented a similar quality to that obtained with manual instrumentation followed by the lateral condensation technique. Similar healing rates of apical lesions were also observed.

CLINICAL RELEVANCE

For treating anterior teeth with apical periodontitis, a reciprocating single-file, single-treatment protocol was as effective as a traditional protocol combining hand instrumentation and the lateral compaction obturation technique.

Long-term Outcomes of Endodontic Treatment Performed with Resilon/Epiphany

INTRODUCTION

Resilon (Resilon Research LLC, Madison, CT) with Epiphany Sealer (Pentron Clinical Technologies, Wallingford, CT) was introduced into the market in 2004 as a new method of root canal obturation. This material as well as the traditionally used gutta-percha with AH Plus sealer (Dentsply Maillefer, Tulsa, OK) were in use over a 9-year span in the University of North Carolina endodontic clinics. Although Resilon was initially thought to create a "monoblock" seal between the material and the canal, in vitro studies later suggested this concept not to be true. The long-term outcome of Resilon using a validated radiographic index and a systematic approach has not been reported. The purpose of this retrospective cohort study was to radiographically evaluate the outcome of Resilon/Epiphany-treated root canals compared with traditional gutta-percha/AH Plus.

METHODS

One hundred twenty-five teeth were radiographically evaluated using the periapical index; 80 were treated with Resilon and 45 with gutta-percha. Age, sex, tooth position, and number of months to follow-up were documented, and a multivariate analysis with odds ratio was performed.

RESULTS

Resilon-treated teeth were 5.3 times more likely to have a periapical index of 3 to 5 at follow-up compared with gutta-percha (P = .009). Teeth presenting with preoperative lesions, regardless of the material used, were also more likely to present with a lesion at follow-up (P = .04).

CONCLUSIONS

Teeth obturated with Resilon were more likely to present with a lesion at follow-up compared with gutta-percha obturated teeth after controlling for the presence of a preoperative lesion and the length to follow-up.

The fate of root canals obturated with Thermafil: 10-year data for patients treated in a master's program

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.

Quality aspects of ex vivo root canal treatments done by undergraduate dental students using four different endodontic treatment systems

OBJECTIVE

To evaluate factors associated with treatment quality of ex vivo root canal treatments performed by undergraduate dental students using different endodontic treatment systems.

MATERIAL AND METHODS

Four students performed root canal treatment on 80 extracted human teeth using four endodontic treatment systems in designated treatment order following a Latin square design. Lateral seal and length of root canal fillings was radiographically assessed; for lateral seal, a graded visual scale was used. Treatment time was measured separately for access preparation, biomechanical root canal preparation, obturation and for the total procedure. Mishaps were registered. An ANOVA mirroring the Latin square design was performed.

RESULTS

Use of machine-driven nickel-titanium systems resulted in overall better quality scores for lateral seal than use of the manual stainless-steel system. Among systems with machine-driven files, scores did not significantly differ. Use of machine-driven instruments resulted in shorter treatment time than manual instrumentation. Machine-driven systems with few files achieved shorter treatment times. With increasing number of treatments, root canal-filling quality increased, treatment time decreased; a learning curve was plotted. No root canal shaping file separated.

CONCLUSIONS

The use of endodontic treatment systems with machine-driven files led to higher quality lateral seal compared to the manual system. The three contemporary machine-driven systems delivered comparable results regarding quality of root canal fillings; they were safe to use and provided a more efficient workflow than the manual technique. Increasing experience had a positive impact on the quality of root canal fillings while treatment time decreased.

Comparison of PathFile and ProFinder Systems to Create a Glide Path in Curved Root Canals

Objective:

Root canal shaping is as important as irrigation and filling when attempting to obtain a high success rate in endodontic treatment. The creation of a glide path before the use of rotary instruments reduces the risk of posterior iatrogenic errors. The objective of the present study was to evaluate instrumentation time and root canal transport after using 2 different glide path rotary systems.

Methods:

In total, 60 mesiobuccal root canals of mandibular molars, with curvature angles between 11° and 82°, were standardized to measure 15 mm. The specimens were divided into 2 groups, depending on their angles of curvature (11º–38º and 39º–82º), and further divided into 4 groups (n=15). Two groups were instrumented using the PathFile system and the other 2 using the ProFinder system. The angle and radius of curvature were measured at the most abrupt angle of curvature before and after instrumentation. Both measurements were analyzed and compared using AutoCAD software to determine canal transportation. Curvature angles were compared using Student’s t test and the radii of curvature using the Wilcoxon test. The time for instrumentation was also evaluated using Student’s t tests.

Results:

There were no statistically significant differences between the two systems with respect to root canal transport (P>0.05); however, the ProFinder system took a longer time to create a glide path (P=0.004).

Conclusion:

Both systems were equally effective in creating a glide path; however, the PathFile system proved to be faster than the ProFinder system.

Contemporary Root Canal Preparation: Innovations in Biomechanics

Root canal preparation must serve the goals of supporting debridement while exerting the least amount of structural damage. Toward those goals, several recent trends for innovation are noted: some changes in instrument design, several of them substantial, whereas others are rather discrete. In vitro testing is ongoing and, because of the lack of consistent methodology, gives only some guidelines for clinical use. Lastly, clinical outcome data are lacking for many current instruments; therefore, it is not clear if improvements in flexibility and resistance to fatigue will translate to better outcomes.

Root dentine and endodontic instrumentation: cutting edge microscopic imaging

Cutting of the dental hard tissues is an integral part of restorative dentistry. Cutting of the root dentine is also needed in preparation prior to endodontic treatment, with significant commercial investment for the development of flexible cutting instruments based around nickel titanium (NiTi) alloys. This paper describes the evolution of endodontic cutting instruments, both in materials used, e.g. the transition from stainless steel to NiTi, and the design of the actual instruments themselves and their method of activation-by hand or motor driven. We have been examining tooth-cutting interactions microscopically for over 25 years using a variety of microscopic techniques; in particular, video-rate confocal microscopy. This has given a unique insight into how many of the procedures that we take for granted are achieved in clinical practice, by showing microscopic video images of the cutting as it occurs within the tooth. This technology has now been extended to allow imaging of the endodontic instrument and the root canal wall for the first time. We are able to image dentine distortion and crack propagation during endodontic filing of the root canal space. We are also able to visualize the often claimed, but seldom seen action of contemporary endodontic instruments.

Influence of Cervical and Apical Enlargement Associated with the WaveOne System on the Transportation and Centralization of Endodontic Preparations

INTRODUCTION

The aim of this study was to evaluate through computed microtomography the transportation and centralization of root canals instrumented using the WaveOne system (Dentsply Maillefer, Ballaigues, Switzerland) associated or unassociated with previous apical and cervical enlargements.

METHODS

Thirty-six mandibular molars were selected with independent mesial roots and curvatures and randomized into the following groups: PathFile (Dentsply Maillefer) before WaveOne Primary (the PFWO group), ProTaper Universal SX (Dentsply Maillefer) before WaveOne Primary (the SXWO group), and WaveOne Primary (the WO group). Computed microtomographic imaging was performed pre- and postpreparation to obtain measurements of mesial and distal dentin walls and calculations of root canal transportation (%) and centralization. One-way analysis of variance was performed to compare the different groups, repeated measures analysis of variance for comparison of the root thirds in each group, and the Student t test for comparisons between the mesiobuccal and mesiolingual canals.

RESULTS

Transportation of the cervical and middle thirds to the danger zone was observed in both roots, whereas the apical thirds were transported to the outer face of the curvature. In the PFWO and SXWO groups, less transportation was observed in the middle thirds of the mesiobuccal canals compared with the WO group (P < .05). Centralization remained almost unchanged in the SXWO group (P < .05).

CONCLUSIONS

In each group, transportation toward the danger zone was mostly observed in the cervical thirds of the mesiobuccal canals. Cervical or apical enlargement resulted in reduced transportation and improved centralization of the middle thirds compared with the exclusive use of the WaveOne system.

Inadvertent apical extrusion of sodium hypochlorite with evaluation by dental volumetric tomography

This case report describes the tissue injury caused by inadvertently extruded NaOCl through the apical constriction. A 56-year-old female patient with complaints of pain, swelling, and ecchymosis on the left side of her face was referred to our clinic. The symptoms had emerged following root canal treatment of the maxillary left first premolar, and a soft tissue complication due to apical extrusion of NaOCl was diagnosed. Antibiotics and analgesics were prescribed. DVT images revealed that the buccal root apex had perforated the maxillary bone. The patient was followed up every other day and became asymptomatic on the 10th day. Endodontic therapy was completed with routine procedures. Determining working length precisely and following irrigation protocols meticulously are indispensable to prevent this type of complication. 3D visualization of the affected area may reveal the cause of the incident.

Radiographic assessment and chair time of rotary instruments in the pulpectomy of primary second molar teeth: a randomized controlled clinical trial

Background and aims. The superiority of rotary systems has been reported in several clinical studies on permanent teeth. This study consisted of radiographic assessment and chair time of rotary instruments in the pulpectomy of primary second molar teeth.

Materials and methods. In this randomized controlled clinical study, 46 children, 3-6 years of age, were selected. The patients were divided randomly into two groups. In the first group (group A) pulpectomy was carried out with hand instruments and in the second group (group B) the Rotary FlexMaster System was used. T-test and chi-squared test were used to analyze data.

Results. The mean instrumentation time in group A was significantly more than that in group B (P<0.001). Also there was a significant difference between both groups in relation to the distance between the apex of mesial root (P<0.001) and distal root (P=0.007) and the canal filling level.

Conclusion. Superior radiographic findings and less chair time of pulpectomy with rotary instruments in second primary molar teeth were achieved.

Management of sodium hypochlorite extrusion beyond the root apex during root canal treatment: a case report

Sodium hypochlorite (NaOCl) is most commonly used as an irrigating solution in endodontic practice. This paper describes an incident of sodium hypochlorite extrusion past the apex (SHEPA) of the UR3. Management of the condition resulted in hospitalisation of the patient, and intravenous antibiotic and steroid therapy. This case report details the measures that can be employed to reduce the risk of SHEPA and management of its potentially serious complications. The reader should understand the various measures that can be adopted to reduce extrusion of endodontic irrigants beyond the root apex and management following SHEPA.

Evaluation of the efficacy of rotary vs. hand files in root canal preparation of primary teeth in vitro using CBCT

AIM

This in vitro study aimed to evaluate the efficacy of rotary ProFile, ProTaper, Hero Shaper and K-files in shaping ability, cleaning efficacy, preparation time and instrument distortion in primary molars.

METHODS

Sixty extracted primary mandibular second molars were divided into four equal groups: Group I K-file, Group II ProFile, Group III ProTaper file and Group IV Hero Shaper file. The shaping ability was determined by comparing pre- and post-instrumentation CBCT scans and data analysed with SPSS program using the Chi-square test. Cleaning efficacy was evaluated by the degree of India ink removal from the canal walls under stereomicroscopy. Instrumentation times were calculated for each tooth and instrument distortion was visually checked and duly noted. The cleaning efficacy and instrumentation time were determined using ANOVA with Tukey's correction. Instrument distortion was analysed using Chi-square test.

RESULTS

The canal taper was significantly more conical for rotary files as compared to K-files with Chi-square test (p < 0.05). Cleaning efficacy of rotary files with average scores (Groups II- 0.68, III- 0.48 and IV- 0.58) was significantly better than K-files (Group I- 0.93) (p < 0.05). Mean instrumentation time with K-file (20.7 min) was significantly higher than rotary files (Groups II 8.9, III 5.6, and IV 8.1 min) (p < 0.05). Instrument distortion was observed in Group I (4.3%), while none of the rotary files were distorted.

CONCLUSIONS

Rotary files prepared more conical canals in primary teeth than manual instruments. Reduced preparation time with rotary files enhances patient cooperation especially in young children.

Instrument fracture in root canals - where, why, when and what? A study from a student clinic

AIM

To investigate the incidence of instrument fracture during nonsurgical root canal treatment performed by undergraduate dental students and to assess the outcome of the treatment if the remaining fragment was left or removed from the root canal.

METHODOLOGY

A retrospective analysis was performed by reviewing assessment forms (n = 3854) filled out for each root canal treatment over a 10-year period (1997-2006) at the University of Bergen, Norway. Based on the assessment forms, all instrument fractures and data concerning type and dimension of the fractured instruments were identified. Moreover, the affected tooth, root, root curvature and the vertical level of the fragment in the root canal were recorded. To assess the outcome of the root canal treatment, radiographs taken at follow-ups were evaluated by two individual examiners.

RESULTS

The overall incidence of instrument fracture during the period was 1.0% on a tooth level. Instrument fracture occurred significantly more often in molars and in teeth rated as difficult preoperatively. Of all instrument fractures, 39.5% were located in the mesio-buccal canals of molars, and 76.5% of the fragments were located apically. A significant high percentage of instruments of small apical diameter (sizes 006-015) fractured in relative straight root canals. The treatment was successful in 71.4% of the cases where the instrument fragment was removed, but only in 56.5% of the cases where the fragment remained in the root canal. Significantly more instruments were removed from teeth with a primary infection (P ≤ 0.05). The success rate for teeth with instrument fracture was 72.7% for vital teeth, 58.3% for primary infected teeth and 42.9% in retreatment cases.

CONCLUSIONS

Within the limits of the present study, the results indicate that the preoperative diagnosis is important for the final treatment outcome and that removal of the fragment is important in cases with primary infection.

Tissue damage after sodium hypochlorite extrusion during root canal treatment

Sodium hypochlorite solution is toxic to vital tissues, causing severe effects if extruded during endodontic treatment. This paper presents a report on the tissue damage related to inadvertent extrusion of concentrated sodium hypochlorite solution during root canal treatment. A 65-year-old woman was referred with moderate pain, ecchymosis, and severe swelling of the right side of the face. These symptoms appeared immediately after a root canal treatment of the maxillary right canine, which had been started 21 hours earlier. It was diagnosed as air emphysema related to sodium hypochlorite solution extravasation during the endodontic treatment. To avoid this, an initial radiograph should be taken to determine the correct canal working length and confirm root canal integrity.