Characterization of the differential efficacy of austenitic vs martensitic NiTi rotary files in non-surgical root canal retreatment: a micro-CT analysis.

Aim: Our study aims to characterize the differential efficacy of martensitic and austenitic files in root canal retreatment regarding defiling ability, debris management and morphometric features. Materials and methods: A total of 10 human premolar teeth with two separate fully formed roots were selected, prepared with BioRace system (BR) up to a size BR2 (0.04/25). Root canals were filled and then divided according to the file type into two groups (n = 10). Two geometrically identical files have been used with the only difference between them is heat treatment; One Curve (OC) martensitic and One Shape (OS) austenitic. Preoperative and postoperative Micro-CT scans were done for all the samples, and the percent volume of residual filling materials was calculated. Canals reshaping and remaining debris in the canals were assessed by calculating the volume of the canals before and after retreatment using Micro-CT software. Results: The percentages of removed filling materials were similar between both groups (97.2% OC vs 97.8% OS). OS was significantly faster than OC (P < 0.05). Retreatment procedure did not significantly change volume, structure model index, surface area, and canal curvature. OS group transported the canals more than OC at the apical third (P < 0.05). There were no significant differences between both groups concerning un-instrumented surface area and accumulated hard tissue debris (AHTD) (P > 0.05). Conclusion: Under the circumstances of this study, neither file systems could completely remove the filling materials. However, OC resulted in less transportation than OS in the apical one third (P < 0.05). Also, OC resulted less AHTD than OS but with no statistical difference.

Micro-cleanliness of Hard Tissue Debris After Advanced Irrigation and Comparison Between EndoVac and XP-endo Finisher: A Microcomputed Tomographic Study.

INTRODUCTION: Conventional irrigation techniques do not remove debris adequately. The remaining tissue debris cause infection inside the root canal and may also affect the seal of the root canal. The study aimed to compare the ability of EndoVac (EV) with XP-endo finisher (XPF) in debris removal using micro-CT analysis. MATERIALS AND METHODS: We used 12 lower first permanent molar human teeth for this study. The root canals were instrumented using a small TF adaptive system. Then, the volume of debris was calculated. Teeth were divided into two groups, according to advanced irrigation methods, with six teeth per group: EV group and XPF group. The volume of debris was calculated again. The paired-sample t-test was used to compare the volume of the debris before and after the use of advanced irrigation methods with the statistical significance of P < 0.05. The percentage of debris reduction was also calculated. RESULTS: Both EV and XPF showed a significant decrease of debris in the mesial canals (P < 0.05), whereas EV only showed a significant reduction of debris in the distal canals. CONCLUSION: Both EV and XPF were able to significantly reduce debris after instrumentation in the mesial canals of lower first mandibular molars. CLINICAL SIGNIFICANCE: The study provides insight into the recent advanced methods used in debris removal and canal disinfection.

Analysis of the Morpho-Geometrical Changes of the Root Canal System Produced by TF Adaptive vs. BioRace: A Micro-Computed Tomography Study.

We aimed to analyze the morpho-geometric changes of the root canal system created by two rotary systems (TF Adaptive and BioRace) using micro-CT technology. Two concepts of rotary file system kinematics, continuous rotation and adaptive kinematics, were used in root canal preparation. Twenty mandibular molars (n = 20) were selected with the following criteria: the teeth have mesial roots with a single and continuous isthmus connecting the mesiobuccal and mesiolingual canals (Vertucci's Type I configuration) and distal roots with independent canals. Teeth were scanned at a resolution of 14 µm. Canals were divided equally into two groups and then enlarged sequentially using the BioRace system and TF Adaptive system according to manufacturer protocol. Co-registered images, before and after preparation, were evaluated for morphometric measurements of canal surface area, volume, structure model index, thickness, straightening, and un-instrumented surface area. Before and after preparation, data were statistically analyzed using a paired sample t-test. After preparation, data were analyzed using an unpaired sample test. The preparation by both systems significantly changed canal surface area, volume, structure model index, and thickness in both systems. There were no significant differences between instrument types with respect to these parameters (p > 0.05). TF Adaptive was associated with less straightening (8% compared with 17% for BioRace in the mesial canal, p > 0.05). Both instrumentation systems produced canal preparations with adequate geometrical changes. BioRace straightened the mesial canals more than TF Adaptive.

Effects of a Novel NiTi Thermomechanical Treatment on the Geometric Features of the Prepared Root Canal System.

Objectives: This study aimed to compare the ex vivo performance of two rotary nickel-titanium (NiTi) systems with similar designs but manufactured from martensitic and austenitic alloys, the One Curve (OC) and One Shape (OS) rotary endodontic files, respectively. Methods: Forty separate mesial canals of 20 extracted mandibular molars were scanned using micro-computed tomography (CT), which were divided into 2 groups and instrumented with OC and OS, respectively. Post-instrumentation micro-CT scans were evaluated using validated computer algorithms to compare changes in canal thickness, surface area, structure model index (SMI) scores, volume of removed dentin, percentage of untreated canal surface, percentage of curvature straightening, and the amount of canal transportation. Results: Both files led to significant changes in the basic root canal geometry, with no preparation errors and no statistically significant differences. However, OC treatment resulted in significantly less curvature straightening (17.30%; 10.77%) (independent samples t test, p < 0.05) and less apical transportation (55.11 µm; 33.15 µm) (Mann-Whitney U, test p < 0.05) compared to OS treatment. Transportation values in the middle and coronal thirds were statistically similar (independent sample t-test, p > 0.05). OC treatment produced significantly less straightening and less apical transportation than OS.

Dental Panoramic Radiographic Indices as a Predictor of Osteoporosis in Postmenopausal Saudi Women.

BACKGROUND: Many oral presentations of osteoporosis-a bone metabolic disease-were recorded. Thus, we aimed to assess panoramic radiomorphometric indices with bone mineral density (BMD) values among Saudi postmenopausal women and its importance in the prediction of osteoporosis. METHODS: A total of 431 Saudi women were enrolled in this study. Panoramic radiographs were obtained at the time of BMD measurement. Subjects were fatherly classified into; normal BMD, osteopenia, and osteoporosis groups. Serum follicle-stimulating hormone, luteinizing hormone (LH), estradiol (E2), 25-hydroxy-vitamin D (25[OH]D) and intact-parathyroid hormone were measured. Moreover, serum creatinine, calcium, and phosphate, together with serum osteocalcin (s-OC), procollagen type I N-terminal propeptide (s-PINP) and cross-linked C-terminal telopeptide of type 1 collagen (s-CTX) were measured. Receiver-operator curve (ROC) curve analysis for use of mandibular cortical width (MCW), panoramic mandibular index (PMI), and maxillary-mandibular ratio (M/M ratio) to differentiate women with osteoporosis or osteopenia from normal subjects was calculated. Cut off values of 4.6 at T score <-1 and 4.1 at T score ≤-2.5 were used. RESULTS: Body mass index is significantly low in the osteoporotic group. There is no significant difference in serum levels of LH, E2, calcium, phosphate, and 25(OH)D between the studied groups. Moreover, s-OC, C-terminal propeptide of procollagen type I, s-PINP, s-CTX, and urinary-CTX are significantly higher in osteoporosis than normal and osteopenia groups. ROC curve analysis revealed that MCW and PMI showed significant data while M/M ratio is non-significant. CONCLUSIONS: It could be concluded that MCW as an important panoramic radiographic parameter can be used for prediction and diagnosis of osteoporosis in postmenopausal Saudi women with low BMD.

Administration of articaine anesthesia may lead to superior profound pulpal anesthesia compared with lidocaine in adult patients.

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION: The pulpal anesthetic efficacy of articaine versus lidocaine in dentistry: a meta-analysis. Brandt RG, Anderson PF, McDonald NJ, Sohn W, Peters MC. J Am Dent Assoc 2011;42(5):493-504. REVIEWER: Khaled Balto, BDS, DMSc PURPOSE/QUESTION: Does articaine anesthesia in the management of irreversible pulpitis result in superior pain control compared with the traditionally used lidocaine? SOURCE OF FUNDING: Information not available TYPE OF STUDY/DESIGN: Systematic review with meta-analysis of data LEVEL OF EVIDENCE: Level 2: Limited-quality, patient-oriented evidence STRENGTH OF RECOMMENDATION GRADE: Grade B: Inconsistent or limited-quality patient-oriented evidence.

Root-filled teeth with adequate restorations and root canal treatment have better treatment outcomes.

DATA SOURCES: Medline, Embase, the Cochrane Library, the Wiley online database, four journals (Journal of Endodontics, International Endodontic Journal, Oral Surgery Oral Medicine Oral Pathology Oral Radiology and Endodontology and Endodontics and Dental Traumatology) and the references of identified articles were searched manually. There was no language restriction. STUDY SELECTION: Clinical studies that provided sample size, and where success was based on radiographic and/or clinical criteria that evaluated quality of root filling, the quality of coronal restoration and periapical status at least one year after root canal treatment that provided an overall success rate or sufficient data to allow it to be calculated from the raw data were included. DATA EXTRACTION AND SYNTHESIS: Data were collected based on predetermined criteria. Percentages of teeth without apical periodontitis were recorded for each category: adequate root canal treatment (AE); inadequate root canal treatment (IE); adequate restoration (AR); and inadequate restoration (IR). Data were analysed using meta-analysis for odds ratios (ORs). RESULTS: Nine article were included . After adjusting for significant covariates to reduce heterogeneity, the results were combined to obtain pooled estimates of the common OR for the comparison of AR/AE versus AR/IE:-AR/AE versus AR/IE (OR = 2.734; 95%CI, 2.61-2.88; P < .001)AR/AE versus IR/AE (OR = 2.808; 95% CI, 2.64-2.97; P < .001). CONCLUSIONS: On the basis of the current best available evidence, the odds for healing of apical periodontitis increase with both adequate root canal treatment and adequate restorative treatment. Although poorer clinical outcomes may be expected with adequate root filling-inadequate coronal restoration and inadequate root filling-adequate coronal restoration, there is no significant difference in the odds of healing between these two combinations.

Tooth survival after root canal treatment.

DATA SOURCES: Medline, the Cochrane Library, hand searches of the International Endodontic Journal, Journal of Endodontics, Oral Surgery Oral Medicine Oral Pathology Oral Radiology and Endodontics, Dental Traumatology (& Endodontics) and bibliographies of all relevant articles and review articles. Unpublished studies were identified by searching abstracts and conference proceedings. Personal contacts were used to identify ongoing or unpublished studies. Two reviewers independently assessed and selected the studies with disagreements being resolved by discussion. STUDY SELECTION: Clinical studies of RCTx on more than 30 teeth and of at least six-month duration, where the success was based on survival of tooth and the proportion of teeth surviving was given, or could be calculated from the raw data, were included. DATA EXTRACTION AND SYNTHESIS: Data were extracted by two reviewers independently using custom-designed forms. The weighted pooled proportion of teeth surviving after treatment and the combined effects (expressed as odds ratio) of clinical factors on tooth survival were estimated using fixed and random effects meta-analyses using DerSimonean and Laird's methods. The survival data were pooled into three groups based on the duration after treatment: 2 or 3 years; 4 or 5 years; and 8, 9 or 10 years. Statistical heterogeneity amongst the studies was assessed by Cochran's (Q) test. RESULTS: Of the 31 articles identified, 14 studies were included. The majority (10) were retrospective. The reported survival is shown in Table 1. Substantial differences in study characteristics were found to hinder effective direct comparison of findings. Evidence for the effect of prognostic factors on tooth survival was weak. Based on the data available for meta-analysis, four conditions were found to significantly improve tooth survival. In descending order of influence, the conditions increasing observed proportion of survival were as follows: (i) a crown restoration after RCTx; (ii) tooth having both mesial and distal proximal contacts; (iii) tooth not functioning as an abutment for removable or fixed prosthesis; and (iv) tooth type or specifically non-molar teeth. Statistical heterogeneity was substantial in some cases, but its source could not be investigated because of insufficient available information. CONCLUSIONS: The pooled proportion of teeth surviving over 2-10 years following RCTx ranged between 86% and 93%. Four factors (listed above) were identified as significant prognostic factors with concurrence between all three strands of evidence.

How common is tooth pain after root canal treatment?

DATA SOURCES: Medline, the Cochrane Library, TRIP database and Google Scholar, hand searching of articles, reviews and textbooks. STUDY SELECTION: Articles in any language about endodontic procedures, (initial treatment or retreatment and surgical or nonsurgical but not pulpotomy, partial pulpectomy or pulp capping) in permanent teeth that reported on pain at a minimum of six months were included. The main outcome was the presence of all-cause pain, with no differentiation on the basis of aetiologies. The outcome of all-cause pain was considered positive if reported by either the patient or the practitioner. Pain could be spontaneous or provoked by biting, palpation or percussion. DATA EXTRACTION AND SYNTHESIS: Data were extracted independently by two reviewers and STROBE criteria (www.strobe-statement.org) used to assess quality. A summary estimate of persistent all-cause pain frequency was established by using a random-effects meta-analysis. The influence of treatment approach (surgical/nonsurgical), longitudinal study design (prospective/retrospective), follow-up rate and duration, initial treatment versus retreatment, and quality of reporting on the pain frequency estimate was assessed in subgroup analyses. RESULTS: 26 studies that included 5777 teeth with 2996 (51.9%) having follow-up pain information met the inclusion criteria. 168 teeth with pain were identified giving a frequency of 5.3% (95% confidence interval, 3.5%-7.2%, p < 0.001) for persistent all-cause pain. High and statistically significant heterogeneity among studies (I(2) = 80%) was present. In subgroup analysis, prospective studies had a higher pain frequency (7.6%) than retrospectives studies (0.9%). Quality of study reporting was identified as the most influential reason for study heterogeneity. CONCLUSIONS: The frequency of all-cause persistent pain after endodontic procedures was estimated to be 5.3%, with higher report quality studies suggesting >7%.

No high-level evidence to support use of ultrasonic instrumentation for root canal treatment.

DATA SOURCES: Searches were made for suitable reports using the Cochrane Oral Health Group Trials Register, Cochrane Central Register of Controlled Trials, Medline, Embase and LILACS (Latin American and Caribbean Health Sciences Literature), and within the reference lists of identified articles. There were no language restrictions. STUDY SELECTION: Randomised controlled trials (RCT) were selected if they had participants of over 18 years of age who had single and multiple permanent teeth with a completely formed apex and with no evidence of internal resorption, and which required root canal treatment. Individuals undergoing retreatment of a tooth were excluded. DATA EXTRACTION AND SYNTHESIS: Screening of eligible studies was conducted in duplicate and independently. Results were to be expressed as fixed-effect or random-effects models using mean differences for continuous outcomes and risk ratios for dichotomous outcomes with 95% confidence intervals. Heterogeneity was to be investigated including both clinical and methodological factors. RESULTS: No eligible RCT were identified. CONCLUSIONS: This review illustrates the current lack of published or ongoing RCT, and the lack of availability of high-level evidence dealing with clinically relevant outcomes, for the effectiveness of ultrasonic instrumentation used alone or as an adjunct to hand instrumentation for orthograde root canal treatment. Future RCT might focus more closely on evaluating the effectiveness of combinations of these interventions with an emphasis not only on clinically relevant but also patient-centred outcomes.

Single- or multiple-visit endodontics: which technique results in fewest postoperative problems?

DATA SOURCES: The Cochrane Central Register of Controlled Trials, Medline, Embase, six thesis databases (Networked Digital Library of Theses and Dissertations, Proquest Digital Dissertations, OAIster, Index to Theses, Australian Digital Thesis Program and Dissertation.com) and one conference report database (BIOSIS Previews) were searched. There were no language restrictions. STUDY SELECTION: Studies were included if subjects had a noncontributory medical history; underwent nonsurgical root canal treatment during the study; there was comparison between single- and multiple-visit root canal treatment; and if outcome was measured in terms of pain degree or prevalence of flare-up. DATA EXTRACTION AND SYNTHESIS: Data were extracted using a standard data extraction sheet. Because of variations in recorded outcomes and methodological and clinical heterogeneity, a meta-analysis was not carried out, although a qualitative synthesis was presented. RESULTS: Sixteen studies fitted the inclusion criteria in the review, with sample size varying from 60-1012 cases. The prevalence of postoperative pain ranged from 3-58%. The heterogeneity of the included studies was far too great to yield meaningful results from a meta-analysis. CONCLUSIONS: Compelling evidence is lacking to indicate any significantly different prevalence of postoperative pain or flare-up following either single- or multiple-visit root canal treatment.

Insufficient evidence for the effectiveness of ultrasonic instrumentation for root canal treatment.

DATA SOURCES: Relevant studies were sourced using the Cochrane Oral Health Group Trials Register, Cochrane Central Register of Controlled Trials (CENTRAL), Medline and Embase. The reference lists of relevant articles were searched and personal databases of trial reports used, in an attempt to locate additional published and unpublished trials. No language restriction was applied. STUDY SELECTION: Randomised controlled trials (RCT) were selected that involved people of age >/=18 years with single and multiple permanent teeth with a completely formed apex and no evidence of internal resorption, who required root canal treatment. Patients undertaking retreatment of a tooth were excluded. DATA EXTRACTION AND SYNTHESIS: Screening of eligible studies was conducted in duplicate and independently by two review authors. Results were to be expressed as fixed- or random-effects models using mean differences for continuous outcomes and risk ratios for dichotomous outcomes with 95% confidence intervals. Heterogeneity was to be investigated including both clinical and methodological factors. RESULTS: No eligible RCT could be found. CONCLUSIONS: This review illustrates how there are no published or ongoing RCT relevant to this review question and that there is currently insufficient evidence regarding the effectiveness of ultrasonic instrumentation used alone for orthograde root canal treatment. Future RCT might focus more closely on evaluating the effectiveness of hand instrumentation compared with hand instrumentation and adjunctive ultrasonic instrumentation.

Root canal irrigation--which method?

DATA SOURCES: Medline and reference lists of relevant articles were consulted. STUDY SELECTION: Papers were quality assessed by two reviewers: only those addressing passive ultrasonic irrigation (PUI) were included in the review. DATA EXTRACTION AND SYNTHESIS: A qualitative synthesis describing the mechanism and effects of PUI is described. RESULTS: Fifty-four papers were included in the review and a qualitative summary of the findings presented. CONCLUSIONS: PUI appears to be a possible adjunctive treatment for cleaning the root canal system and may be more effective than syringe irrigation. More research is needed to clarify the underlying physical mechanisms through which PUI works.

Calcium hydroxide has limited effectiveness in eliminating bacteria from human root canal.

DATA SOURCES: Searches of Cochrane Central Register of Controlled Trials (CENTRAL), Medline, Embase, six thesis databases (Networked Digital Library of Theses and Dissertations, Proquest Digital Dissertations, OAIster, Index to Theses, Australian Digital Thesis program and Dissertation.com) and one conference report database (BIOSIS Previews) were undertaken. There were no language restrictions. STUDY SELECTION: Studies were included in which participants had a noncontributory medical history, presented with mature teeth and radiographic evidence of periapical bone loss (as an indication of pre-operative canal infection), whose selected root canals had not previously received any endodontic treatment, and who had undergone nonsurgical root canal treatment during the study in which calcium hydroxide had also been used to seal in the canals. In addition, it was required that microbiological sampling had been undertaken during the course of treatment, before canal preparation, after canal preparation and after canal medication. Aerobic and anaerobic culturing techniques were performed on all samples. The treatment outcomes were stated in terms of positive and negative canal cultures. DATA EXTRACTION AND SYNTHESIS: All data were extracted in the same manner using a standardised data extraction sheet. Between-study heterogeneity was assessed using the standard chi-squared test or Q-statistic. The principal measure of treatment effect (antibacterial efficacy) was risk difference, which is normally defined as the risk in the experimental group minus risk in the control group. For the purpose of this study, it is given as the difference in the proportion of bacteria-positive cultures pre- and post-medication. RESULTS: Out of the eight studies (257 cases) included, one study used a small control group (in which canals were left empty, and no intracanal medicament was used between appointments). The other seven studies simply compared the frequency of positive cultures before and after calcium hydroxide medication. Six studies demonstrated a statistically significant difference between pre- and postmedicated canals, whereas two did not. There was considerable heterogeneity among studies. The pooled risk difference was 21% (95% confidence intervals, 6-47%. The difference in the proportion of cases positive for bacteria before and after treatment was not statistically significant (P = 0.12). CONCLUSIONS: Based on the current best available evidence, calcium hydroxide has limited effectiveness in eliminating bacteria from human root canals, when assessed by culture techniques. The quest for better antibacterial protocols and sampling techniques must continue to ensure that bacteria can be reliably eradicated prior to obturation.

Gamma interferon (IFN-gamma) and IFN-gamma-inducing cytokines interleukin-12 (IL-12) and IL-18 do not augment infection-stimulated bone resorption in vivo.

Periapical granulomas are induced by bacterial infection of the dental pulp and result in destruction of the surrounding alveolar bone. In previous studies we have reported that the bone resorption in this model is primarily mediated by macrophage-expressed interleukin-1 (IL-1). The expression and activity of IL-1 is in turn modulated by a network of Th1 and Th2 regulatory cytokines. In the present study, the functional roles of the Th1 cytokine gamma interferon (IFN-gamma) and IFN-gamma-inducing cytokines IL-12 and IL-18 were determined in a murine model of periapical bone destruction. IL-12-/-, IL-18-/-, and IFN-gamma-/- mice were subjected to surgical pulp exposure and infection with a mixture of four endodontic pathogens, and bone destruction was determined by microcomputed tomography on day 21. The results indicated that all IL-12-/-, IL-18-/-, and IFN-gamma-/- mice had similar infection-stimulated bone resorption in vivo as wild-type control mice. Mice infused with recombinant IL-12 also had resorption similar to controls. IFN-gamma-/- mice exhibited significant elevations in IL-6, IL-10, IL-12, and tumor necrosis factor alpha in lesions compared to wild-type mice, but these modulations had no net effect on IL-1alpha levels. Recombinant IL-12, IL-18, and IFN-gamma individually failed to consistently modulate macrophage IL-1alpha production in vitro. We conclude that, at least individually, endogenous IL-12, IL-18, and IFN-gamma do not have a significant effect on the pathogenesis of infection-stimulated bone resorption in vivo, suggesting possible functional redundancy in proinflammatory pathways.

Three-dimensional quantitation of periradicular bone destruction by micro-computed tomography.

We have previously shown that two-dimensional, high-resolution, micro-computed tomography is a rapid, reproducible, and noninvasive method for measuring periradicular bone resorption in mice, giving results virtually identical to histology. In this study, we determined whether a three-dimensional volumetric quantitation of bone resorption could be achieved and whether this correlates with two-dimensional measurements. Periradicular lesions were induced in the lower first molars of mice by pulp exposure and infection; unexposed teeth served as controls. Mandibles were harvested on day 21 and subjected to: (a) three-dimensional micro-computed tomography imaging; and (b) conventional histology. Using a three-dimensional model and a semiautomatic contouring algorithm, we determined three-dimensional void volume, void surface, void thickness, and the standard deviation of the thickness distribution. The results showed a significant correlation between lesion void volume and two-dimensional lesion area by histology (r2 = 0.73), as well as high correlations between void volume and void thickness (r2 = 0.86) and standard deviation of the void thickness (r2 = 0.87), but no relationship with void surface. These results show that three-dimensional analysis of micro-computed tomography images is highly correlated with two-dimensional cross-sectional measures of periradicular lesions. Nevertheless, micro-computed tomography allows assessment of additional microstructural features as well as sub-regional analysis of lesion development.

A mouse model of inflammatory root resorption induced by pulpal infection.

OBJECTIVE: The present study was undertaken to determine the frequency and extent of apical root resorption associated with induced periradicular lesions in mice. STUDY DESIGN: Bone and root resorption was quantified by using two- and three-dimensional micro-computed tomography (mu-CT) in the lower first molars of mice subjected to pulp exposure and infection. RESULTS: mu-CT measurements showed significant apical resorption in exposed and infected teeth, resulting in an average distal root shortening of 12.7% (P <.001 vs unexposed). These findings were confirmed with three-dimensional reconstituted images that showed thinning and shortening of the distal root. Tartrate-resistant acid phosphatase clastic cells were associated with resorption lacunae on the cementum of root apices, as well as on bone at the periphery of the periradicular lesions. Brown and Brenn staining showed the presence of bacteria in dentinal tubules adjacent to resorbed cementum. CONCLUSIONS: Apical root resorption is a prominent and consistent finding associated with periradicular infection in the mouse. This species represents a convenient model for studying the pathogenesis of inflammatory root resorption in vivo.