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Less-experienced operators have been shown to require additional training to achieve results similar to those of experienced operators. However, clinical data comparing the survival and success of ceramic restorations by experienced and less-experienced operators by using the computer-aided design and computer-aided manufacturing (CAD-CAM) technology are lacking.The purpose of this retrospective clinical study was to analyze and compare the clinical performance of CAD-CAM lithium disilicate restorations fabricated by less-experienced (predoctoral dental students) and experienced (dentists) operators.Patients who received an adhesively luted CAD-CAM lithium disilicate restoration between 2011 and 2019 were included in the study. Clinical performance was assessed by calibrated examiners by using World Dental Federation (FDI) criteria. Success and survival were calculated by the Kaplan-Meier method and statistically compared by log-rank tests and univariate Cox regression analyses. FDI criteria were compared by using Mann-Whitney-U tests (α=.05).Ninety-two restorations (students: n=65, dentists: n=27) were assessed (mean ±standard deviation time from insertion: 4.04 ±1.55 years). The survival rates after 2 years (students: 93.8%, mean annual failure rate [mAFR]: 3.1%; dentist: 96.3%, mAFR: 1.9%) and after 4 years (students: 87.3%, mAFR: 3.3%; dentists: 88.3%, mAFR: 3.1%) were not significantly different (P=.525). Also, success rates after 2 (students: 90.8%, mAFR: 4.7%; dentists: 92.6%, mAFR: 3.8%) and 4 years (students: 82.4%, mAFR: 4.7%; dentists: 76.1%, mAFR: 6.6%) were not significantly different (P=.778). FDI criteria were also not significantly different between less-experienced and experienced operators (P≥.110).Operator experience did not affect the short-term clinical performance of CAD-CAM lithium disilicate restorations.

Objectives The aim of this study was to evaluate the effectiveness of different fiber post removal techniques and to correlate dentinal loss with microcrack formation. Materials and methods Forty-five extracted single-rooted teeth were root canal treated and fiber posts were adhesively luted. Specimens were divided into three groups (n = 15) according to the removal technique: long-shaft round bur (EndoTracer #08, Komet, Lemgo, Germany), SonicFlex Endo (KaVo, Biberach, Germany), DT Post Removal Kit (VDW, Munich, Germany). Roots were scanned before post cementation and after post removal using micro-computed tomography. Dentin loss, residual luting material, working time, and the induction of microcracks were assessed. Statistical analysis was performed by using multiple contrast tests (max-t tests, α = 0.05). Correlations between parameters dentin loss/new microcracks and dentin loss/residual material were calculated using Kendall’s tau. Results Post removal with SonicFlex Endo resulted in the highest amount of removed dentin with significant differences to the round bur and the DT Post Removal Kit. No technique was found to completely remove the post and luting material. All techniques induced microcracks with the DT Post Removal Kit presenting the highest number of new defects. No correlation between dentin loss and new microcracks was observed. Deviations from the original root canal occurred in all groups, but no perforation was observed. Conclusions All techniques resulted in dentin loss, residual luting material, and the formation of microcracks. However, no correlation between dentin loss and the induction of microcracks was observed. Clinical relevance As all techniques resulted in microcrack formation and dentin loss, this study emphasizes the risk of iatrogenic damage due to post removal procedures.

Objectives This study assessed the influence of preparation size on the efficacy of shock wave–enhanced emission photoacoustic streaming (SWEEPS) and conventional irrigation (CI) on removal of accumulated hard tissue debris (AHTD) from isthmus-containing mandibular molars using micro-computed tomographic analysis. Materials and methods Sixty extracted mandibular molars with two mesial canals connected by an isthmus were selected. Canals were shaped with Mtwo instruments (VDW, Munich, Germany) up to sizes 25/.06, 40/.04 or 40/.06 (n = 20), and specimens were distributed into 2 final irrigation groups (n = 10): SWEEPS and CI. Roots were scanned at a resolution of 10.5 µm before and after preparation and final irrigation. Data sets were co-registered, and the percentage reduction of AHTD calculated for each specimen was statistically compared using analysis of variance with a of 5% significance level. Results The preparation size did not significantly influence the percentage reduction of AHTD (p p p p Conclusions Removal of AHTD was not significantly affected by the preparation size. SWEEPS was associated with significantly less debris than CI. Clinical relevance SWEEPS performed significantly better than CI regarding the removal of AHTD from isthmus-containing mandibular molars irrespective of the preparation size.

Sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA) and/or calcium hydroxide (Ca(OH)To assess the effectiveness of root canal irrigation and dressing for the treatment of teeth with apical periodontitis (AP).A search was conducted in the PubMed-MEDLINE, Scopus, EMBASE, Google scholar databases and available repositories, followed by hand searches, until July 2021. Eligibility criteria followed the a priori formulated Population, Intervention, Comparator, Outcomes, Timing, and Study design (PICOTS) framework. Clinical studies restricted to English language were included. The revised Cochrane risk-of-bias tool for randomised trials (RoB 2) was used to assess the quality of included studies. Meta-analyses were performed using the fixed-effect model to obtain Risk Ratio (RR) and 95% Confidence Interval (CI), with sensitivity analysis. Overall quality of evidence of meta-analyses was assessed through the Grading of Recommendations Assessment, Development, and Evaluation tool.The search identified 1357 records of which six fulfilled the inclusion criteria, providing data for 'irrigation' from 212 teeth and for 'dressings' from 438 teeth. Two studies reported no significant difference regarding the outcome 'pain at 7 days' using 2% chlorhexidine vs. 5.25% NaOCl and EDTA or after using different concentrations of NaOCl (1% vs. 5%). No significant difference was detected between different NaOCl concentrations regarding the reduction of AP. A meta-analysis was possible for the comparison of single-visit (SV) versus multiple-visits including the use of Ca(OH)The use of Ca(OH)There is moderate certainty that SV treatment is associated with better radiographic evidence of normal periodontal ligament space (strict criteria) compared with the use of Ca(OH)PROSPERO database CRD42021260271.

The aim of this study was to investigate the influence of moisture content in frozen and embalmed human cadavers on the detection of dentinal microcracks using micro-computed tomography (micro-CT). The group of embalmed specimens included three mandibular and two maxillary segments each containing one tooth. The group of frozen cadavers consisted of two frozen mandibular bone-blocks with two teeth and one mandibular segment containing one tooth. The final number of teeth for each preservation method was n = 5. All specimens were scanned with eight different moisture conditions: 48 h wet, 2 h dry, 48 h wet, 24 h dry, 48 h wet, 1 wk dry, 48 h wet, 1 wk dry. Micro-CT images were screened for the presence of dentinal microcracks. Statistical analysis was performed by nonparametric analysis of variance (α = 5%). Only few microcracks were observed in wet and in 2 h dried bone-blocks with no significant differences (p = 0.63 and p = 0.23, respectively). There was a significant and steady increase of microcracks within the groups of dried specimens as follows: 2 h dry24 h dry first wk dry second wk dry (all p 0.008). Preservation method had no significant influence on the visibility of microcracks (p = 0.98). Identification of dentinal microcracks on micro-CT images is influenced by moisture content of cadaveric bone-blocks irrespective of the preservation method.

Introduction Aim was to analyze and compare the efficacy of different bleaching agents typically used for internal bleaching of endodontically-treated discolored teeth. Methods Electronic databases (PubMed, Web of Science, Cochrane Library) were searched by two reviewers for clinical trials in which the color of endodontically-treated discolored teeth, before and after internal bleaching, was examined using shade guide units (ΔSGU) or a spectrophotometer/colorimeter (ΔE). The efficacies of the bleaching agents were compared using subgroup analyses. Statistical heterogeneity was assessed with Cochran’s Q and I2-statistic. Publication bias was evaluated using funnel-plots. Results Eight studies were included in the systematic review, out of which six could be included in the meta-analyses. Internal bleaching led to a significant change in tooth shade (ΔSGU: 6.27 [95%-CI: 5.36–7.17], ΔE: 12.83 [95%-CI: 9.46–16.20]). With regard to ΔSGU, the use of carbamide peroxide (35% or 37%), hydrogen peroxide (35%), and the combination of sodium perborate and hydrogen peroxide (3% or 30%) led to better bleaching effect than did sodium perborate (padj.≤0.026). Regarding ΔE, there were no significant differences between carbamide peroxide (37%), hydrogen peroxide (35%) and sodium perborate mixed with hydrogen peroxide (p=0.051). Risk of bias of included studies was classified as moderate to high. Conclusions Carbamide peroxide, hydrogen peroxide, and sodium perborate have a significant bleaching effect on discolored, root-canal-treated teeth. For a valid assessment of shade stability and comparison of bleaching agents resp. their concentrations, further studies with long term recalls are necessary.

This study evaluated the effect of three different NiTi instrumentation techniques on the incidence of microcracks after the preparation of straight and curved root canals using micro-CT. Roots from mandibular premolars and maxillary molars (n = 66) with the same mean canal curvatures were assigned to three groups of straight and three groups of curved roots (n = 11). After preoperative micro-CT scans, root canals were prepared with Reciproc, OneShape and ProTaper Next to size 25. Specimens were scanned again, and pre- and post-operative cross-sectional images (n = 75 263) were screened to identify the presence of dentinal microcracks. Overall, microcracks were detected in 2.97% (n = 2236) of the cross-sectional images. No new dentinal microcracks were observed after root canal instrumentation of straight and curved canals with the tested NiTi systems. Instrumentation with Reciproc, OneShape and ProTaper Next did not induce the formation of dentinal microcracks irrespective of canal curvature.

For patients with dementia, dental care can pose a considerable challenge due to cognitive impairment, behavioral, and psychological symptoms, and (often subsequently) limited autonomous oral care. In this study, we aimed to assess the proficiency of dentists in general practice in the outpatient dental care of these patients. A total of 119 dentists from private practices in Lower Saxony, Germany, participated in this study. Concerning treatment of patients with dementia, they provided details about (1) practice equipment/consultation, (2) training/ expertise, and (3) special circumstances of dental treatment.Participating dentists predominantly reported to use medical aids (e.g., positioning cushions) to improve the treatment situation for patients with dementia. Over two thirds (68.6%) offered consultations in nursing homes, and at the patients’ homes (47.0%). The training rate was remarkably low in the field of gerodontology for dentists and their practice staff (< 10%), however, 54.5% expressed interest in such training. The majority of dentists reportedly adapted their treatment strategy to the needs of patients with dementia (e.g., communication, inclusion of caregivers, time management). Furthermore, most participants adapted dental treatment adequately (e.g., strict indication for tooth extraction, simple design of dental prostheses).In summary, even though training in the field of gerodontology must be considered insufficient, most dentists in this study showed an adequate adaptation of their treatment strategy as well as consideration of dental characteristics in patients with dementia, along with interest in trainings. We conclude that dementia-specific training should be expanded in the field of dentistry, preferably already at university level.

Manufacturers offer single-file instrumentation systems with matching gutta-percha (GP) cones to simplify root canal preparation and obturation. The purpose of this study was to determine whether file diameters and tapers match with corresponding cone diameters and tapers (precision) as well as industry standards (accuracy).Twenty files and corresponding GP cones from each size of F360 (#25, #35, #45, #55 with .04 taper) and Reciproc (#25, #40, #50 with variable tapers) instruments were examined by using optical microscopy (×32) to determine their diameter and taper. Precision was evaluated by using one-way analysis of variance (α = 0.05) with Scheffé post hoc tests and t tests with Bonferroni correction. Accuracy was calculated by subtracting the nominal values from the measured values of all files and GP cones, and mean diameter and taper differences were compared by using one-way analysis of variance (α = 0.05) and Scheffé post hoc test for pairwise comparison.For F360, the majority of file and cone diameters were within the tolerance levels, but most of the file diameters were significantly larger than GP cone diameters (P .05), but the majority of all measured values were within the tolerance levels. For Reciproc, file and cone diameters at D1 and D3 mostly approached the nominal values. At the coronal end, file diameters #25 and #50 were significantly smaller than cone diameters (P .05). For both instrumentation systems, almost all file and cone tapers matched with the preset tolerance ranges. For Reciproc, significant differences between file and GP cone demonstrated either smaller cone or smaller file diameters and tapers, depending on the size. Most of the measured values were within the acceptable range, but diameters at the coronal end exhibited the highest percent difference from the nominal values.Despite the call for standardization, variability in diameter and taper dimensions between single-file instrumentation systems and their corresponding GP cones can be expected.

AIM To evaluate ex vivo the efficacy of ProTaper Universal Retreatment files (Dentsply Sirona, Ballaigues, Switzerland) in removing Thermafil, GuttaCore (both Dentsply Sirona) or vertically compacted gutta-percha from curved root canals using micro-CT. METHODOLOGY Sixty curved molar roots with the same mean canal curvatures and radii in two directions were prepared using ProFile instruments (Dentsply Sirona) to size 30 with .04 taper and obturated with either Thermafil, GuttaCore or vertically compacted gutta-percha and AH Plus (n = 20). Specimens were retreated using the ProTaper Universal Retreatment files D1, D2 and D3 to working length, and root canal preparation was completed with ProTaper Next (Dentsply Sirona) to size ×4. Percentages of residual filling material and dentine removal were assessed using micro-CT imaging. Working time and procedural errors were recorded. Statistical analysis was performed using Kruskal-Wallis and Wilcoxon tests. RESULTS No significant differences between carrier-based and warm vertical compaction regarding residual filling material (14.2-19.3%) and dentine removal (2.7-3.2 mm3 ) were detected (P > 0.05). Time to reach working length was significantly faster for canals filled with GuttaCore than that observed for Thermafil and warm vertical compaction (P

Die chemomechanische Aufbereitung des Wurzelkanalsystems stellt den wichtigsten Bestandteil der endodontischen Therapie dar und beeinflusst den Erfolg der Behandlung masgeblich. In diesem Beitrag werden die mikrobiologischen Grundlagen endodontischer Erkrankungen, die Eigenschaften und Limitationen verschiedener Spulflussigkeiten sowie unterschiedliche Systeme und Techniken fur die Applikation und Aktivierung dieser Spulflussigkeiten vorgestellt. Weiterhin werden die Vor- und Nachteile ein- und mehrzeitiger Wurzelkanalbehandlungen diskutiert und verschiedene intrakanalare Medikamente hinsichtlich ihrer antimikrobiellen Wirksamkeit bewertet. Abschliesend werden Desinfektionsprotokolle fur verschiedene klinische Situationen abgeleitet.

The aim of the present study was to perform a representative survey among German dentists about attitudes, practice, and experience regarding single-tooth repair restorations.An anonymous questionnaire was designed and mailed to all registered dentists in Lower Saxony (n = 6600). Twenty-eight percent were returned (n = 1852), and n = 1805 could be analyzed. Statistical analyses were done by Wilcoxon signed-rank tests, Kruskal-Wallis tests, and ordered logistic regressions (p 0.05).Only 2.2 % of the dentists declared to never perform repair restorations. Composite restorations were repaired significantly more often than all other materials. Frequency of performing repair restorations was partially associated to dentist-related factors. The decision for repairing a restoration was dependent on several tooth- and restoration-associated variables. The main indications for repair were the partial loss of restoration or adjacent tooth structure as well as chipping and endodontic access cavities of crowns. Repair restorations were mostly done with composite using various different preconditioning techniques. Overall patients' acceptance was reported to be high. Most of the dentists considered repair restorations as permanent restoration with a moderate to high longevity. Estimated success of repair restorations depended significantly on the dentists' experiences (frequency and techniques of repair restorations).Repair restorations were often performed and were well accepted by dentists and patients, but indications for repair restorations as well as applied materials and techniques varied distinctly.Repairs of single-tooth restorations are well accepted and frequently performed, but indications, techniques, and materials require further research.

To evaluate the efficacy of sonically and ultrasonically activated irrigation on removal of accumulated hard-tissue debris (AHTD) in mesial root canal systems of mandibular molars using micro-computed tomographic (micro-CT) analysis.Forty mesial roots of mandibular molars with two independent canals joined apically by an isthmus (Vertucci type II) were selected. The root canals were instrumented using Reciproc R25 instruments, and specimens were scanned at a resolution of 10.5 μm. Subsequently, n = 10 roots were assigned to each of the four final irrigation groups such that the group means and variances were almost identical: sonically activated irrigation with EndoActivator (EA) or EDDY (ED), ultrasonically activated irrigation (UAI) and manual irrigation without activation (MI). The final irrigation procedures were performed using a total of 5 mL 1% NaOCl and 5 mL 15% EDTA per canal over 5 min with activation time of 4 × 20 s. Reconstructed data sets were coregistered, and the mean percentage reduction of AHTD after final irrigation was compared statistically between groups using analysis of variance at a significance level set at 5%.A significant reduction of AHTD was achieved after final irrigation in all groups (P 0.05), ranging from 44.1% to 66.8%. The vol% of debris after irrigation was 3.7 ± 1.9% for EA, 3.3 ± 2.3% for ED, 2.1 ± 1.6% for UAI and 4.4 ± 2.3% for MI, with no significant difference between groups (P 0.05).None of the final irrigation protocols completely removed AHTD from mesial root canal systems in extracted human mandibular molars. Sonically and ultrasonically activated irrigation performed no better compared to manual irrigation.

Aim To evaluate the effect of moisture content in root canal dentine on detection of microcracks using micro-computed tomography. Methodology Ten roots with and without craze lines or cracks (each n = 5) were selected and scanned six times with different moisture conditions of root dentine using a micro-CT scanner at a high resolution of 10.5 μm. Scanning conditions were as follows: 1. after 30 d wet storage, 2. after 2 h dry time, 3. after 48 h wet storage, 4. after 24 h dry time, 5. after 48 h wet storage, 6. after 2 h dry time. From each scan, cross-sectional images were obtained at intervals of 1 mm (total n = 708) and evaluated for the presence of dentinal microcracks twice by 5 calibrated blinded observers. Statistical analysis was performed by nonparametric analysis of variance for longitudinal data (P < 0.05). Results Intra-rater percentage agreement ranged between 92% and 98%, whereas inter-rater percentage agreement was 81% and 83%, respectively. No significant differences between all wet groups as well as between both groups with 2 h dry time were detected (P > 0.05). Almost no cracks were observed after wet storage with a significant increase of cracks after 2 h dry time (P < 0.001). Significantly more microcracks were identified after 24 h than after 2 h dry time (P < 0.004). Conclusions Moisture content of dentine influenced detection of microcracks when evaluated using micro-CT. Scanning should be performed on dried specimens to allow reliable identification of dentinal defects. Formation of new cracks during dry periods up to 24 h was disproved. This article is protected by copyright. All rights reserved.

Rodig T, Hausdorfer T, Konietschke F, Dullin C, Hahn W, Hulsmann M. Efficacy of D-RaCe and ProTaper Universal Retreatment NiTi instruments and hand files in removing gutta-percha from curved root canals – a micro-computed tomography study. International Endodontic Journal, 45, 580–589, 2012. Abstract Aim To compare the efficacy of two rotary NiTi retreatment systems and Hedstrom files in removing filling material from curved root canals. Methodology Curved root canals of 57 extracted teeth were prepared using FlexMaster instruments and filled with gutta-percha and AH Plus. After determination of root canal curvatures and radii in two directions, the teeth were assigned to three identical groups (n = 19). The root fillings were removed with D-RaCe instruments, ProTaper Universal Retreatment instruments or Hedstrom files. Pre- and postoperative micro-CT imaging was used to assess the percentage of residual filling material as well as the amount of dentine removal. Working time and procedural errors were recorded. Data were analysed using analysis of covariance and analysis of variance procedures. Results D-RaCe instruments were significantly more effective than ProTaper Universal Retreatment instruments and Hedstrom files (P

Rodig T, Hirschleb M, Zapf A, Hulsmann M. Comparison of ultrasonic irrigation and RinsEndo for the removal of calcium hydroxide and Ledermix paste from root canals. International Endodontic Journal, 44, 1155–1161, 2011. Abstract Aim To compare the efficacy of ultrasonic irrigation and RinsEndo in removing calcium hydroxide and Ledermix paste from simulated root canal irregularities. Methodology The root canals of sixty extracted single-rooted teeth were prepared using FlexMaster rotary instruments to size 60, 0.02 taper. The roots were split longitudinally, and a standardized groove was prepared in the apical part of one segment. The teeth were randomly allocated into two groups (n = 30), according to the intracanal dressing. In the first group, grooves were filled with calcium hydroxide paste (Calxyl), whereas the grooves in the second group were filled with Ledermix paste. After reassembly, the root canals were completely filled with the respective medicament using a lentulo. The removal of medicament dressing was performed after 7 days with either passive ultrasonic irrigation or RinsEndo and 1% sodium hypochlorite for 3 min. The amount of remaining medicament was evaluated under a microscope with 30 × magnification using a four-grade scoring system. A regression analysis with P ≤ 0.05 was performed. Results Ledermix paste removal was significantly more effective than the removal of calcium hydroxide (P

Rodig T, Sedghi M, Konietschke F, Lange K, Ziebolz D, Hulsmann M. Efficacy of syringe irrigation, RinsEndo® and passive ultrasonic irrigation in removing debris from irregularities in root canals with different apical sizes. International Endodontic Journal, 43, 581–589, 2010. Abstract Aim To compare of the efficacy of syringe irrigation, RinsEndo® (Durr Dental, Bietigheim, Germany) and passive ultrasonic irrigation (PUI) in the removal of dentinal debris from simulated irregularities in root canals with different apical sizes. Methodology Thirty extracted human pre-molars were randomly divided into three groups (n = 10) followed by root canal preparation with rotary FlexMaster® NiTi instruments (VDW, Munich, Germany) to size 30, 0.02 taper (group 1), size 40, 0.02 taper (group 2) or size 50, 0.02 taper (group 3). The teeth were split longitudinally, and a standard groove and three hemispherical-shaped cavities were cut into the root canal halves. Grooves and cavities were filled with dentinal debris before each irrigation procedure and the root halves were reassembled. In all groups three different irrigation procedures were performed with 30 mL NaOCl (1%) and (i) syringe, (ii) RinsEndo® and (iii) PUI. The amount of remaining debris was evaluated under a microscope with 30× magnification and a four score system. The data were analysed with a non-parametric analysis of covariance and multiple comparisons using the Tukey adjustment (P = 0.05). Results Passive ultrasonic irrigation removed debris significantly better from the artificial canal irregularities than RinsEndo® and syringe irrigation irrespective of the root canal diameter. Only in group 1 (30, 0.02 taper) the difference between PUI and RinsEndo® was not statistically significant (P = 0.99). RinsEndo® demonstrated significantly better results than syringe irrigation in all groups (P

Rodig T, Vogel S, Zapf A, Hulsmann M. Efficacy of different irrigants in the removal of calcium hydroxide from root canals. International Endodontic Journal. 43, 519–527, 2010. Abstract Aim To compare the efficacy of different solutions (1% sodium hypochlorite, 10% citric acid and 20% EDTA) in the removal of calcium hydroxide from root canals. Methodology One hundred single-rooted maxillary incisors were prepared to size 50 and split longitudinally. Two standardized grooves were cut into the apical and coronal part of the root canal dentine and filled with calcium hydroxide. The reassembled teeth were irrigated with a syringe and a size 30 needle using the following irrigants: (i) 20% EDTA, (ii) 10% citric acid, (iii) 1% NaOCl, (iv) 10% citric acid + 1% NaOCl, (v) 20% EDTA + 1% NaOCl and (vi) water (control). Volume of irrigant was 20 mL in each group, and irrigation time was 5 min. Evaluation of cleanliness of the blinded specimens was performed by two calibrated observers under a microscope with 30× magnification using a four-grade scoring system as described by van der Sluis et al. (2007). Statistical evaluation was performed using a SAS-macro for non-parametric multifactorial analysis (P

Aim To compare root canal preparation using ProFile .04 and GT Rotary nickel–titanium instruments (both Dentsply Maillefer, Ballaigues, Switzerland). Methodology Fifty extracted mandibular molars with mesial root canal curvatures between 20 and 40° were randomly divided into two groups and embedded in a muffle system. All root canals were prepared to size 45 using ProFile .04 or GT rotary instruments. The following parameters were evaluated: straightening of root canal curvature, postoperative root canal cross-section, cleaning ability, safety issues and working time. Results Both NiTi systems maintained curvature well; the mean degree of straightening was

Although endodontic irrigants are generally considered to be safe, severe complications can occur during or as a consequence of root canal irrigation. However, no data on the incidence of irrigation incidents could be found. In the following paper, a review is presented on the possible incidents that may occur during root canal irrigation with different irrigation solutions, the sequelae, as well as prevention and therapy of such intra- and post-operative problems.

Aim To present a case of a mandibular second premolar with three root canals. Summary An accurate diagnosis of the morphology of the root canal system is a prerequisite for successful root canal treatment. A review of the literature reveals a low incidence of all types of premolars with three root canals. Diagnostic means such as preoperative radiographs and examination of the pulp chamber floor aid the location of root canal orifices. The diagnostic and therapeutic problems concerning premolars with unusual anatomy are described on the basis of a clinical example. A case report describes the successful treatment of a mandibular second premolar with three root canals. Key learning points • Clinicians should be aware of unusual root canal anatomy in mandibular premolars. • Radiographs exposed at two different horizontal angles and their careful interpretation facilitate the search of additional root canals. • The use of magnification and additional lighting are recommended for the clinical examination of the pulpal floor.

To compare the efficacy of reciprocating and rotary NiTi-instruments in removing filling material from curved root canals using micro-computed tomography.Sixty curved root canals were prepared and filled with gutta-percha and sealer. After determination of root canal curvatures and radii in two directions as well as volumes of filling material, the teeth were assigned to three comparable groups (n = 20). Retreatment was performed using Reciproc, ProTaper Universal Retreatment or Hedström files. Percentages of residual filling material and dentine removal were assessed using micro-CT imaging. Working time and procedural errors were recorded. Statistical analysis was performed by variance procedures.No significant differences amongst the three retreatment techniques concerning residual filling material were detected (P 0.05). Hedström files removed significantly more dentine than ProTaper Universal Retreatment (P 0.05), but the difference concerning dentine removal between both NiTi systems was not significant (P 0.05). Reciproc and ProTaper Universal Retreatment were significantly faster than Hedström files (P = 0.0001). No procedural errors such as instrument fracture, blockage, ledging or perforation were detected for Hedström files. Three perforations were recorded for ProTaper Universal Retreatment, and in both NiTi groups, one instrument fracture occured.Remnants of filling material were observed in all samples with no significant differences between the three techniques. Hedström files removed significantly more dentine than ProTaper Universal Retreatment, but no significant differences between both NiTi systems were detected. Procedural errors were observed with ProTaper Universal Retreatment and Reciproc.

To compare the efficacy of hand and rotary nickel-titanium (NiTi) instruments in removing filling material from curved root canals of root filled teeth with unknown preparation parameters.Ninety mandibular molars with root fillings in curved root canals and homogenous root canal filling extending to 0-2 mm short of the radiographic apex were selected. Root canal curvatures and radii were measured in two directions and microcomputed tomography (micro-CT) scans were used to determine preoperative volumes of the filling material. Subsequently, the teeth were assigned to two identical groups (n = 14). The root fillings were removed with Hedström files or FlexMaster NiTi rotary instruments. Postoperative micro-CT imaging was used to assess the percentage of residual filling material as well as the amount of dentine removal. Working time and procedural errors were recorded. Data were compared using analysis of covariance and analysis of variance procedures.Root canals retreated with Hedström files were associated with less remaining filling material compared with FlexMaster instruments (P0.05). Both retreatment techniques removed similar amounts of dentine with no significant differences (P0.05). FlexMaster instruments were significantly faster than Hedström files (P0.05). No procedural errors were detected in the Hedström group, whilst three instruments fractured in the FlexMaster group.Hand instrumentation resulted in significantly less residual filling material than retreatment with rotary NiTi instruments. Dentine removal was not significantly different for both techniques. FlexMaster NiTi rotary files were significantly faster than Hedström files, but were associated with a higher risk of instrument fracture.

To compare the efficacy of ultrasonic irrigation and RinsEndo in removing calcium hydroxide and Ledermix paste from simulated root canal irregularities.The root canals of sixty extracted single-rooted teeth were prepared using FlexMaster rotary instruments to size 60, 0.02 taper. The roots were split longitudinally, and a standardized groove was prepared in the apical part of one segment. The teeth were randomly allocated into two groups (n = 30), according to the intracanal dressing. In the first group, grooves were filled with calcium hydroxide paste (Calxyl), whereas the grooves in the second group were filled with Ledermix paste. After reassembly, the root canals were completely filled with the respective medicament using a lentulo. The removal of medicament dressing was performed after 7 days with either passive ultrasonic irrigation or RinsEndo and 1% sodium hypochlorite for 3 min. The amount of remaining medicament was evaluated under a microscope with 30 × magnification using a four-grade scoring system. A regression analysis with P ≤ 0.05 was performed.Ledermix paste removal was significantly more effective than the removal of calcium hydroxide (P0.0001), whereas irrigation technique was not a significant factor (P = 0.3712). The percentages of complete removal of calcium hydroxide and Ledermix paste were 11.7% and 51.7%, respectively.None of the irrigation techniques was able to completely remove the intracanal medicaments from the apical part of the root canal. Irrespective of the irrigation technique, significantly less Ledermix paste was detected compared with calcium hydroxide.

Introduction The aim of this study was to evaluate the cleaning efficacy of different irrigant agitation techniques on debris and smear layer removal in curved root canals. Methods Mesiobuccal root canals of 108 mandibular molars were shaped with nickel-titanium instruments, and a final rinse of NaOCl and ethylenediaminetetraacetic acid was performed. Specimens were assigned to 4 groups (n = 20) and submitted to the following irrigation agitation techniques: no agitation (control), ultrasonic, EndoActivator, and CanalBrush. Root canals were split longitudinally and subjected to scanning electron microscopy. The presence of debris and smear layer at coronal and apical levels was evaluated by using a 5-grade scoring system with 200× and 1000× magnification, respectively. Results Concerning debris removal, no significant differences among groups were detected. In the coronal region, agitation of the irrigants resulted in significantly more smear layer removal than the control. EndoActivator was significantly more effective than ultrasonic agitation and CanalBrush. Conclusions In curved root canals, activation of NaOCl and ethylenediaminetetraacetic acid did not enhance debris removal but resulted in significantly more effective smear layer removal at coronal levels.

Introduction: The aim of this study was to compare the efficiency of a sonic device (Vibringe), syringe irrigation, and passive ultrasonic irrigation in the removal of debris from simulated root canal irregularities. Methods: Root canals with 2 standardized grooves in the apical and coronal parts were filled with dentin debris. Three different irrigation procedures were performed with NaOCl (1%) and (1) syringe irrigation, (2) Vibringe, and (3) passive ultrasonic irrigation. The amount of remaining debris was evaluated by using a 4-grade scoring system. Results: Ultrasonic irrigation removed debris significantly better from the artificial canal irregularities than the Vibringe System and syringe irrigation (P < .0001). The Vibringe System demonstrated significantly better results than syringe irrigation in the apical part of the root canal (P = .011). Conclusions: Passive ultrasonic irrigation is more effective than the Vibringe System or syringe irrigation in removing debris. The sonic device demonstrated significantly better results than syringe irrigation in the apical root canal third. (J Endod 2010;36:1410‐1413)

The aim was to evaluate subjectivity (using inter- and intraexaminer repeatability), the effect of examiner experience, and residual caries diagnostic accuracy with visual tactile (VT) criteria and using a caries disclosing agent (CD). Thirty teeth with occlusal caries were excavated by a single operator not involved in the diagnostic part of the study. A test area was marked in each cavity. Four dentists with more than five and five dentists with less than five years' experience rated the marked area twice (a week apart) using VT criteria. A week later, the samples were stained using Caries Detector. The same examiners rated the presence or absence of stain in the marked area twice (a week apart). Undecalcified thin slices were examined for bacteria using light microscopy. Overall kappa for inter-examiner repeatability was higher for CD (0.45) than VT (0.31). In the less experienced group the kappa value was higher for CD (0.41) than for VT (0.23). In the experienced group kappa was lower for CD (0.43) than for VT (0.46). Median kappa for intra-examiner repeatability was higher for caries detector (0.77, 0.53) compared to visual tactile (0.52, 0.34) for the more and less experienced examiners respectively. There was no significant difference between the experienced and the inexperienced group in combined sensitivity and specificity (mean) for VT (0.52, 0.53) or CD (0.60, 0.58).VT was more subjective than CD, except for experienced examiners who had a higher inter-examiner repeatability for VT than CD. Diagnostic accuracy for residual caries does not increase with experience.

Crown fractures are the most common form of traumatic dental injuries in the permanent dentition. Reattachment of the coronal fragment to the remaining tooth structure may offer a conservative, esthetic and cost-effective restorative option which has been shown to be an accepted alternative to conventional restoration (resin composite build-up, veneer or crown) of the fractured teeth. Fragment retention is significantly influenced by reattachment techniques and materials. Regarding reattachment techniques, placement of an internal groove seems advisable when the remnant and the fragment fit well, while an overcontouration should be used when the partial loss of hard tissue must be compensated. Materials used for reattachment seem to be less important than technique for a successful treatment, but adhesives and composite resin materials should correspond to each other. However, up to now, self-etching adhesives have shown less fracture strength of the reattachment than multi-bottle adhesives. Since many case reports and several clinical studies reported clinical success, further studies are recommended to analyse the impact of reattachment techniques and materials on the long-term survival of fragment bonding.

The aim of this study was to compare the preparation of oval distal root canals in mandibular molars using three different nickel-titanium (NiTi) instruments: Lightspeed (Lightspeed Inc., San Antonio, TX, USA). ProFile .04 (Maillefer Ballaigues. Switzerland) and Quantec SC (Tycom, Irvine, CA, USA).Three groups of 20 extracted mandibular molars with oval distal root canals were embedded in a muffle system as described by Bramante et al. (1987) and modified by Hülsmann et al. (1999). Preparation of the root canals was performed with particular emphasis on the buccal and lingual extensions of the oval shape. The following parameters were evaluated: comparison of pre- and postoperative photographs with regard to the buccal and lingual extensions of the preparation, safety issues (file fractures, perforations, apical blockages, loss of working length), cleaning ability (SEM investigated using a 5-score system for remaining debris and smear layer) and working time.Superimposition of pre- and postoperative cross-sections in the majority of specimens revealed uninstrumented or incompletely instrumented buccal or lingual extensions (Lightspeed and Quantec SC, 56.7%; ProFile .04, 55%) For debris removal, Quantec SC achieved the best results (54.2% scores 1 and 2), followed by ProFile .04 (52.5%) and Lightspeed (46.7%). Preparation resulted in substantial smear layer covering the canal walls for every system (ProFile .04, 38.3%; Quantec SC, 36.6%; Lightspeed, 28.3%). Differences between the three systems were not significant for any of the parameters investigated. Preparation with Lightspeed resulted in two fractured instruments; with Quantec SC. two apical blockages occurred. With ProFile .04, no complications were noticed. Mean working time was shorter for ProFile .04 (261.2 s) than for Quantec SC (272.4 s) and Lightspeed (338.9 s); the differences were not significant.The flexibility of the NiTi instruments investigated in this study did not allow controlled preparation of the buccal and lingual extensions of oval root canals. The instruments frequently produced a circular bulge in the canal whilst the buccal and lingual extensions remained unprepared, leaving smear layer and debris.