Outcome of selective root canal retreatment-A retrospective study.

AIM: Selective root canal retreatment is when the treatment is limited to root(s) with radiographic evidence of periapical pathosis. The goals of this retrospective study were as follows: (i) evaluate the clinical and radiographic (periapical radiographs [PR] or cone-beam computerized tomographs [CBCT]) outcome of selective root canal retreatment after ≥12 months follow-up; (ii) evaluate the periapical status of the unretreated roots; and (iii) assess tooth survival. METHODOLOGY: A retrospective study (January 2018 to April 2021) was conducted to identify permanent multirooted teeth that underwent selective root canal retreatment. Clinical records, PR and CBCT were examined to ascertain variables of interest. Outcomes (per root and per tooth) were classified into 'favourable' or 'unfavourable' using well-established clinical and radiographic healing criteria. Treatment outcomes for the whole tooth and per root were compared as well as bivariate associations between the treatment outcome of the retreated roots and the treatment-related parameters (quality of root filling, sealer extrusion, iatrogenic mishaps and type of restoration) were analysed using Fisher's exact test (α = .05). Survival was recorded in months. RESULTS: A total of 75 teeth (195 roots) in 75 subjects were available for outcome analysis. The favourable outcome per tooth was 86.7%. At follow-up, 92.6% of the retreated roots had a favourable outcome. From the unretreated roots, 3.5% showed radiographic signs of an emerging periapical lesion. No statistical difference was shown between the outcomes per root and per tooth between both groups. None of the treatment-related parameters had a direct influence on the outcome of the retreated roots. The survival rate at 12-48 months after retreatment was 91.5%. CONCLUSIONS: Selective root canal retreatment is associated with a favourable outcome in a majority of cases. Unretreated roots rarely developed radiographic signs of a new periapical lesion at follow-up. Future high-quality clinical trials with larger sample sizes and longer follow-up periods are required to confirm these findings.

Teaching rotary root canal instrumentation using a Peyton teaching approach.

INTRODUCTION: The aim of the study was two evaluate the effectiveness of a Peyton teaching approach for rotary root canal instrumentation, in comparison to the traditional "see one-do one" method. MATERIAL AND METHODS: Forty undergraduate students were randomly divided into two groups (n = 20). Students of the first group (G1) were taught how to use rotary instrumentation using a modified Peyton method, whilst the second group (G2) watched a teaching video (30 min) on the same subject. Both groups instrumented a plastic block and subsequently both mesial canals of an extracted lower molar. The quality of the root canal instrumentation was analysed by 2 blinded observers on video recordings and x-rays. RESULTS: Interobserver correlation was 0.917 (p < .0005; Pearson) for the assessment of the video recordings; students of G1 received significantly more total points (83.55 ± 6.82 points) compared to G2 (69.76 ± 13.82) (p = .001; t-test), the gender had no significant effect on the overall results (p = .444; two-way ANOVA). Significant differences were detected for the categories "initial scouting," "coronal enlargement," "glide path preparation," "preparation using X2 file," "preparation using X3 file" (p < .05; t-test) as well as for the subcategories "sequence of rinse, recapitulation, rinse" (p = .001; t-test) and "recapitulation" (p < .002; t-test). No differences between groups were observed for the radiographic evaluation with respect to working length and canal straightening. CONCLUSION: Teaching rotary instrumentation by using the Peyton approach resulted in improved performance of undergraduate students assessed with a checklist-based process analysis. Enhanced implementation of rotary instrumentation could result in better long-term results of students' root canal treatment.

Evidence and consequences of academic drift in the field of dental research: A bibliometric analysis 2000-2015.

The mission of academic excellence has resulted in a science system that incentivises publications within high impact, often basic science journals, and less in application-oriented journals. For the dental research field this so-called academic drift can result in a research portfolio that moves away from research that serves dental healthcare. Therefore, we examined if and how academic drift has changed the dental research field. Web of Science data were used to develop a network map for dental research containing journal clusters that show similar citation behavior. From the year 2000 up to 2015, we explored the intensity of knowledge exchange between the different clusters through citation relations. Next, we analyzed changes in research focus of dental research institutes in seven countries, in dental research, clinical medicine research, basic science, public health research and other fields. Within the citation network, 85.5% of all references in dental journals concern references to other dental journals. The knowledge contribution of non-dental research fields to dental research was limited during the studied period. At the same time, the share of output of dental research institutes in dental research has declined. The research activity of the dental research institutes increased mainly in basic science while the knowledge input from basic science into dental research did not increase. Our findings suggest that the dental research portfolio is influenced by academic drift. This academic drift has increased the disbalance towards basic science, and presents a challenge for the scientific progress in dental healthcare services.

The effect of photodynamic therapy on postoperative pain in teeth with primary endodontic infection.

INTRODUCTION: The objective of this study was to investigate the action of photodynamic therapy on pain control after endodontic treatment in asymptomatic teeth with a primary infection, within a single visit. METHODS: Sixty (60) single-rooted teeth with pulp necrosis and periapical lesions were selected and randomly divided into two (2) groups (n = 30), according to the protocol; a control group (CG) and a group using photodynamic therapy (aPDT). The canals were instrumented with Reciproc files # 25 up to 40 along the entire length of the canal, using 2% chlorhexidine gel as the auxiliary chemical substance, followed by irrigation with sterile saline. aPDT consited of 0.005% methylene blue as photosensitizer, using AsGaAl diode laser, 660 nm wavelength, 100 mW of power and 9 J of energy, using optical fibers with 365 µm in diameter. The canals were filled with Endomethasone N cement. RESULTS: Pain intensity was assessed at 8, 12, 24, 48, 72 h and 1 week after endodontic treatment using a visual analogue scale. The level of pain was classified as none (0), mild (1-3), moderate (4-7) or severe (8-10). The data were at a significance level of 5%. There was a statistically significant difference (p<0.05) in the periods of 8, 12, 24, 48 and 72 h between the control group and the aPDT group. After 1 week, there was no statistically significant difference. CONCLUSIONS: It is concluded that photodynamic therapy had a significant effect on decreasing post-endodontic treatment pain in teeth with necrotic pulp and asymptomatic periapical lesions.

Establishing the research agenda for oral healthcare using the Dialogue Model-patient involvement in a joint research agenda with practitioners.

Engagement of patients in the composition of a research agenda is essential to reduce the gap between research and practice and thereby generate more impact. The aim of this study was to develop a research agenda for oral health. Experienced challenges and needs with oral health(care) of practitioners and patients formed the input for the research agenda. We describe the identification of research priorities of patients and the integration of these with previously identified research priorities of practitioners, using a participatory multi-phase approach for research agenda setting (Dialogue Model). Via focus group discussions, 32 research topics were generated. Next, 1495 patients prioritized these topics in an online survey. In a dialogue meeting, a joint research agenda of eight research topics was agreed upon. Many topics were contributed by patients, but were prioritized by both stakeholder groups. The most important topics concerned behavior change and the relation between general and oral health. Other topics that were prioritized covered affordability and accessibility as well as health system research and organizational issues. By considering different perspectives, this research agenda has uncovered directions for future research that go beyond evident research topics, as many topics are currently underrepresented in oral healthcare research.

The Effect of Ultrasonic Agitation on the Porosity Distribution in Apically Perforated Root Canals Filled with Different Bioceramic Materials and Techniques: A Micro-CT Assessment.

The present study evaluated the effect of ultrasonic agitation on the porosity distribution of BioRoot RCS/single gutta-percha cone (BR/SC) and MTA Flow (MF) root canals fillings used as apical plugs in moderately curved and apically perforated roots. Eighty mesial root canals of mandibular first molars were enlarged up to ProTaper NEXT X5 rotary instrument 2 mm beyond the apical foramen, simulating apical perforations. Specimens were randomly divided into four experimental groups (20 canals per group) according to the material and technique used for root canal obturation: BR/SC, BR/SC with ultrasonic agitation (BR/SC-UA), MF and MF with ultrasonic agitation (MF-UA). The ultrasonic tip was passively inserted into the root canal after the injection of flowable cement and activated for 10 s. The specimens were scanned before and after obturation with a high-resolution micro-computed tomography scanner, and the porosity of the apical plugs was assessed. The differences between groups were analyzed using the Kruskal-Wallis and Mann-Whitney tests, with the significance level set at 5%. None of the obturation materials and techniques used in this study was able to provide a pore-free root canal filling in the apical 5 mm. Considerably higher percentages of open and closed pores were observed in the MF and MF-UA groups, with the highest porosity being in the MF-UA group (p < 0.05). No significant differences were observed between the BR/SC and BR/SC-UA groups, where the quantity of open and closed pores remained similar (p > 0.05).

Reduction of dual-species biofilm after sonic- or ultrasonic-activated irrigation protocols: A laboratory study.

AIM: To evaluate the antibacterial effect of sonic- and ultrasonic-activated irrigation on bacterial reduction of a dual-species biofilm in root canals compared to nonactivated irrigation in a laboratory study. METHODOLOGY: Two hundred and forty extracted human single-rooted maxillary anterior teeth were divided into two main groups (G, n = 120) according to the initial preparation size of the root canal (G1: size 25, 0.06 taper, G2: size 40, 0.06 taper). Root canals were inoculated with Enterococcus faecalis and Streptococcus oralis. After 5 days, G1 received combined instrumentation (up to size 40, 0.06 taper) and irrigation/activation, whereas G2 received solely irrigation/activation protocols. In both groups, irrigation was performed with sodium hypochlorite (NaOCl 1%) or physiological saline (NaCl 0.9%), using nonactivated syringe irrigation, sonic activation (2 x 30 s) or ultrasonic activation (2 x 30 s). Logarithmic reduction factors (LRFs) of colony-forming units were analysed separately for dentine-adherent and planktonic bacteria immediately after irrigation/activation protocols (time-point 1) or after 5 days of further incubation (time-point 2) by analysis of variance (anova) and post hoc tests (Tukey's HSD, t-test). The significance level was set at 0.05. RESULTS: In G1 subgroups (combined instrumentation with irrigation/activation), LRFs were significantly affected by the applied irrigation solution (p < .0001), but not by the activation method (p > .05; anova). In G2 subgroups (solely irrigation/activation), both, irrigant solution and activation, significantly affected LRFs (p < .0001, anova). Sonic activation resulted in significantly higher LRFs than ultrasonic activation (p < .0001) which had significantly greater reductions than nonactivated irrigation (p < .05; Tukey's HSD). At T2, strong bacterial regrowth was observed in all groups; however, a significant bacterial reduction was detected for factors instrumentation, irrigant solution and activation (p < .0001; anova). Similar LRFs were found for dentine-adherent and planktonic bacterial cells in all groups (r = 0.91 at T1, r = 0.8 at T2). CONCLUSIONS: In this laboratory study on extracted maxillary anterior teeth high-frequency sonic activation resulted in a greater bacterial reduction compared to ultrasonic activation in groups receiving solely irrigation/activation protocols; however, irrigation using NaOCl and ultrasonic activation also contributed significantly to bacterial reduction compared to the control groups.

Porosity Distribution in Single Cone Root Canal Fillings Performed by Operators with Different Clinical Experience: A microCT Assessment.

The objective of this study was to assess the porosity distribution of BioRoot RCS/single gutta-percha point root-canal fillings performed by a general dental practitioner and endodontist. Fourteen plastic models of maxillary premolars with two roots were selected and shaped with HyFlex EDM instruments to a size 40/0.04 taper and randomly divided into two experimental groups. A total of 14 canals in each group were obturated by two different operators with one HyFlex EDM size 40 gutta-percha point and BioRoot RCS sealer. The specimens were scanned with a high-resolution micro-computed tomography scanner, and the porosity of the fillings at the coronal, middle, and apical thirds of the root canals was qualified and quantified. The differences between groups and root-canal thirds were compared using Mann-Whitney, Friedman, and Wilcoxon tests with the significance level set at p < 0.05. The highest number of pores was observed in the apical third of root-canal fillings in both groups; however, the porosity distribution between the two groups was not significantly different in the apical and middle thirds (p > 0.05). Statistically significant differences were determined only in the coronal third (p < 0.05). The predominance of open pores was detected in all root-canal thirds and groups, with no significant differences in the number of open pores between the coronal and middle thirds (p > 0.05).

Diagnosis of Vertical Root Fractures by Cone-beam Computed Tomography in Root-filled Teeth with Confirmation by Direct Visualization: A Systematic Review and Meta-Analysis.

INTRODUCTION: The purpose of this review was to determine the diagnostic accuracy of cone-beam computed tomographic (CBCT) imaging in detecting vertical root fractures (VRFs) in root-filled teeth compared with a reference standard (direct visualization). METHODS: Electronic searches were performed in Medline, Scopus, Cochrane, and gray literature for English language articles until June 2020. Prospective and retrospective clinical studies using CBCT imaging to diagnose VRFs in root-filled teeth were included. Case reports and in vitro studies were excluded. The Quality Assessment of Diagnostic Accuracy Studies 2 tool was used to assess the risk of bias and applicability concerns. Meta-analysis was performed using Stata 16.1 software (StataCorp, College Station, TX) via the MIDAS v.3.0 package and METANDI module. Publication bias was evaluated using Deeks' funnel plot analysis. Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) was performed to evaluate the certainty of evidence. This systematic review was registered in the Open Science Framework (10.17605/OSF.IO/7JKE2). RESULTS: Eight articles were included in this systematic review and meta-analysis. Risk of bias assessment showed that 5 articles in the patient selection domain had low risk of bias with low applicability concern. In the index test and reference standard domains, 7 articles had moderate risk of bias with moderate applicability concern. Three articles had high RB in the flow and timing domain. There was no publication bias. CBCT imaging had a pooled sensitivity and specificity of 0.78 (95% confidence interval [CI], 0.64-0.88) and 0.80 (95% CI, 0.63-0.91), respectively, and an accuracy of 0.86 (95% CI, 0.83-0.89). CBCT imaging also had pooled positive and negative likelihood ratios of 4 and 0.2, respectively. In GRADE analysis, the quality of evidence was low for sensitivity and moderate for specificity when CBCT imaging was used for the diagnosis of VRF. CONCLUSIONS: The overall quality assessment of the included articles showed that in the patient selection domain, the risk of bias was low, and it was moderate in the index test and reference standard domains. Evidence from this systematic review and meta-analysis indicates that CBCT imaging is still not a good tool for diagnosing VRFs in root-filled teeth compared with direct visualization.

Microcomputed Tomographic Assessment of the Single Cone Root Canal Fillings Performed by Undergraduate Student, Postgraduate Student and Specialist Endodontist.

The present study evaluated the obturation quality of root canals filled with BioRoot RCS sealer and single gutta-percha point by undergraduate student (US), postgraduate student (PS) and endodontist (ED). Twenty-one plastic models of upper premolars were enlarged with HyFlex EDM instruments to a size 40/0.04 taper and randomly divided into three groups (7 teeth/14 canals per group): US, PS and ED. After the obturation of root canals with BioRoot RCS and one HyFlex EDM size 40 gutta-percha point, plastic models were scanned using micro-computed tomography scanner (µCT) SkyScan 1272 at isotropic resolution of 10 µm. The porosity distribution was evaluated separately for the apical, middle and coronal thirds. The Kruskal-Wallis, Mann-Whitney, Friedman and Wilcoxon tests with the significance level set at 5% were used for data analysis. The µCT evaluation revealed open pores being the dominant type of porosity in all experimental groups and root canal thirds, with the highest percentage of pores in the apical third of root canal fillings. The quality and homogeneity of single cone root canals fillings remained similar between the groups in the apical and middle thirds (p > 0.05). Significant differences were observed only in the coronal third (p < 0.05).

Research priorities for oral healthcare: agenda setting from the practitioners' perspective.

OBJECTIVES: The aim of this study was to develop a research agenda based on the most important information needs concerning the effects and outcomes of oral healthcare provided by oral healthcare professionals (OHPs). METHODS: A two-stage survey study was used to identify and prioritise topics for future research. The first survey generated topics based on information needs by OHPs. Topics were clustered thematically and overlapping topics were merged in 84 research themes. In the second survey, respondents selected their top 5 from the 84 research themes. Themes were sorted by the rank number based on rank sum. RESULTS: In the first survey, 937 topics were suggested. Almost half (n = 430, 46%) were identified as topics related to endodontology, cariology, oral medicine/surgery or tooth restoration. Topics were grouped in 84 research themes, covering 10 research domains. These were prioritised by 235 OHPs. Behaviour change for oral health and oral healthcare for geriatric patients ranked as most important. CONCLUSIONS: Consultation of OHPs has resulted in a research agenda, which can be used to inform programming future oral health research. The highest prioritised research themes have an interdisciplinary nature, mainly concern oral disease prevention and are under-represented in the current oral healthcare research portfolio.

Multimodular Assessment of a Traumatic Bone Cyst Overlapped with Apical Periodontitis.

Traumatic bone cyst (TBC), a "pseudocyst" that usually affects long bones, is a rare lesion among cystic lesions in the jaws. The most commonly affected site is the posterior mandible. Most of the time, TBC is asymptomatic and discovered during routine radiographic examination. The treatment recommended for TBC is surgical exploration followed by curettage of the bony walls, which also serves as a diagnostic procedure. A 27-year-old Caucasian male with a noncontributory medical history was referred to our department for the endodontic evaluation of the mandibular right first and second molars, which were connected to an extensive asymptomatic osteolytic lesion. A multimodular diagnostic assessment involving CBCT imaging, ultrasound, and histopathologic examination led to a definite diagnosis of a TBC overlapping with apical periodontitis (AP). Subsequently, a multidisciplinary treatment approach was performed, including surgical excision and biopsy of the lesion, endodontic retreatment of the right mandibular first molar, and postsurgical root canal treatment of the second molar. During the follow-up period of five years, the patient was reassessed periodically once a year and showed, in the absence of signs and symptoms, progressive healing of the affected area. The present article reports a case following the CARE guidelines of a TBC combined with AP where a multimodular diagnostic assessment was performed and discusses the possible pathogenetic mechanisms involved in its generation.

Correction to: The effectiveness of ultrasound examination to assess the healing process of bone lesions of the jaws: a systematic review.

The given names of the authors are swapped with their family names.

The Effect of Pulpotomy Base Material on Bacterial Penetration and Proliferation for Pulpotomized Primary Molar Teeth: A Confocal Laser Scanning Microscopy Study.

Introduction: the study aimed to evaluate Enterococcus Faecalis colonization in the pulp chamber in pulpotomized extracted human teeth filled by different pulpotomy base materials (PBMs), using confocal laser scanning microscopy (CLSM). Study design: Cavity preparations were made in 70 extracted primary molars. The pulp chambers were filled using either Intermediate restorative material (IRM), Mineral Trioxide Aggregate (MTA) or Glass ionomer (GI). Twenty-five teeth served controls. The specimens were sterilized, and coronally filled with bacterial suspension for 21 days. The specimens were cut through the furcation area, stained using LIVE/DEAD BacLight Bacterial Viability Kit and evaluated using CLSM. Results: The extent of fluorescent staining was larger in the GI group, compared to the IRM and MTA groups, and larger in the IRM group compared to the MTA group (P<0.05). The minimal and maximal bacterial penetration depths into the dentinal tubules were 55 and 695μm, respectively (mean 310μm), without differences between the materials (GI, IRM, MTA, p>0.05). The ratio of live bacteria to dead bacteria within the evaluated areas was higher in the GI group compared to the IRM and the MTA groups, and higher in the IRM group compared to the MTA group (P<0.05). There were no differences between the mesial, distal and apical parts in any of the evaluations (p>0.05). Conclusions: bacteria colonize the interface between the PBM and dentin and penetrate deeply into the dentinal tubules. The extent and the vitality of the colonized bacteria may be affected by the type of PBM.

Root Canal Preparation Does Not Induce Dentinal Microcracks In Vivo.

INTRODUCTION: This in vivo study aimed to evaluate the development of dentinal microcracks after root canal preparation of contralateral premolars with rotary or hand instruments using micro-computed tomographic technology. METHODS: Sixty contralateral intact maxillary and mandibular premolars in which extraction was indicated for orthodontic purposes were selected and distributed into positive (n = 6, teeth with induced root microcracks) and negative (n = 6, intact teeth) control groups as well as 2 experimental groups (n = 24) according to the instrumentation protocol: ProTaper rotary (PTR) or ProTaper hand (PTH) systems (Dentsply Maillefer, Ballaigues, Switzerland). After root canal preparation, teeth were extracted using an atraumatic technique and scanned at a resolution of 17.18 µm. A total of 43,361 cross-sectional images of the roots were screened for the presence of dentinal microcracks. The results were expressed as the percentage and number of root section images with microcracks for each group. RESULTS: All roots in the positive control group showed microcracks at the apical third, whereas no cracks were observed in the specimens of the negative control group. In the PTR group, 17,114 cross-sectional images were analyzed, and no microcrack was observed. In the PTH group, dentinal microcracks were observed in 116 of 17,408 cross-sectional slices (0.66%) of only 1 specimen. These incomplete microcracks extended from the external root surface into the inner root dentin at the area of reduced dentin thickness. CONCLUSIONS: Root canal instrumentation with PTR and PTH instruments of contralateral maxillary and mandibular premolars did not result in the formation of dentinal microcracks in vivo.

Ultrasound Examination to Visualize and Trace Sinus Tracts of Endodontic Origin.

INTRODUCTION: The detection of a tooth with a sinus tract (ST) of endodontic origin and its pathway are conventionally assessed with a periapical radiograph and a gutta-percha cone introduced into its stoma. The aim of this study was to evaluate the possibility to detect STs and trace their route using ultrasound real-time examination. METHODS: Two calibrated examiners performed echography on 10 patients who had a lesion of apical periodontitis (AP) and ST and 10 patients in the control group with AP without an ST recruited in 2 endodontic practices. They also traced the pattern of the STs with a computer program. The images were then submitted to 2 calibrated and blinded observers who were asked to describe the presence of AP and ST and to trace it with the same program. The data obtained were compared with the clinical and radiographic diagnosis of ST. For sensitivity, specificity, accuracy, and positive and negative predictive values, the receiver operating characteristic curve and Fisher exact test were used (P < .05). RESULTS: Interobserver agreement was high as was the diagnostic accuracy of the ultrasound examination of STs (mean value = 97.5%), and the Fisher exact test showed statistical significance (P < .05). High sensitivity and a negative predictive value and 100% specificity and a positive predictive value were also obtained. The application of the 3-dimensional mode further enabled the reconstructions of the more complex paths, and the implementation with color power Doppler disclosed the vascularity surrounding the STs. CONCLUSIONS: The ultrasound examination is a technique feasible to describe and trace the STs of endodontic origin.

Porosity Distribution in Apically Perforated Curved Root Canals Filled with Two Different Calcium Silicate Based Materials and Techniques: A Micro-Computed Tomography Study.

The present study evaluated the porosity distribution of BioRoot RCS/single gutta-percha point (BR/SC) and MTA flow (MF) fillings, which were used as plugs for the apical perforation repair in curved canals of extracted mandibular molars using micro-computed tomography (µCT). Forty mesial root canals of mandibular first molars were shaped with ProTaper NEXT X1-X5 files 2 mm beyond the apex to simulate apical perforations that were randomly divided into two groups (n = 20) according to the material and technique used for the apical plug: BR/SC or MF. The specimens were scanned before and after canal filling at an isotropic resolution of 9.9 µm. The volumetric analysis of voids in the apical 5 mm of the fillings was performed. Data were analyzed using one-way ANOVA with Bonferroni correction (p < 0.05). Micro-computed tomography (µCT) evaluation revealed significant differences between the groups in terms of porosity: the total volume and percentage volume of voids was lower in the BR/SC group in comparison with the MF group (p < 0.05), with the predominance of open pores in both groups. Neither of the materials and/or application techniques were able to produce void-free root fillings in the apical region of artificially perforated curved roots of mandibular molars.

Acidic and alkaline chemicals' influence on a tricalcium silicate-based dental biomaterial.

Bioactive hydraulic tricalcium silicate materials are commonly used in several dental procedures. Mineral Trioxide Aggregate (MTA) is one such material, which is used in a variety of clinical applications, the most recent of which is root canal sealing material, during which, the MTA potentially comes in contact with remnants of the chemical agents used for disinfecting root canals. The effects of commonly used root canal irrigating solutions on MTA have not been investigated in depth, thus far. The aim of this study was to determine the effect of five common chemical agents used in root canal preparation (sodium hypochlorite/NaOCl, ethylene diaminetetraacetic acid/EDTA, mixture of sodium hypochlorite and etidronic acid/NaOCl + EA, mixture of EDTA and Chlorhexidine/QMix, or saline) on a commercial tricalcium silicate (MTA Plus). Samples were analyzed using scanning electron microscopy with energy dispersive spectroscopy, X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy and Inductively coupled plasma techniques to see effects of phases formed and calcium ion release. Specimens immersed in NaOCl and NaOCl + EA had strong peaks for calcium hydroxide, but materials exposed to EDTA and QMix had lesser XRD peaks for calcium hydroxide. The calcium hydroxide peak in the XRD indicates hydration of tricalcium silicate and formation of amorphous calcium silicate hydrate. Calcium released from samples immersed in EDTA and NaOCl was less than in NaOCl + EA and QMix solutions. Fewer calcium phosphate crystals and less calcium hydroxide were observed with the samples in NaOCl, EDTA and QMix, which could have an important impact as it negatively influences the bioactivity. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 107B: 377-387, 2019.

Intra-manufacture Diameter Variability of Rotary Files and Their Corresponding Gutta-Percha Cones Using Laser Scan Micrometre.

INTRODUCTION: Manufacturers offer gutta-percha (GP) cones matched with different sizes of endodontic files as an attempt to simplify the obturation process and create a tight seal in the canal. The purpose of this study was to evaluate whether intra-manufacture GP diameters matched the diameters of their corresponding files at different levels using laser micrometre. METHODS AND MATERIALS: Twenty files and corresponding GP master cones of Reciproc R40 (40/0.06) (VDW, Munich, Germany), WaveOne Large(40/0.08)(Dentsply Maillefer, Ballaigues, Switzerland), ProTaper F3 (30/0.09) (Dentsply Maillefer, Ballaigues, Switzerland), and Mtwo 40/0.06 (VDW, Munich, Germany) were examined using laser micrometre (LSM 6000 by Mitutoyo, Japan) with accuracy of 1 nm to establish their actual diameter at D0, D1, D3 and D6. The data was analysed using the independent t-test. The differences were considered at 0.05. RESULTS: The diameter of GP master cones was significantly larger than that of the corresponding files at all levels in all brands. ProTaper GP diameter was closest to the file diameter at D1 (GP=0.35, File=0.35 mm), and D3 (GP=0.48, File=0.49). CONCLUSION: Within the same manufacturer, GP cone diameters do not match the diameters of their corresponding files. Clinicians are advised to use a GP gauge to cut the tip so as to appropriate the diameter from a smaller sized GP cone.

The Intra-Manufacture Diameter Variability of Rotary Files and Their Corresponding Gutta-Percha Cones Using Laser Scan Micrometer.

Introduction: As an attempt to simplify the obturation process and create a tight seal, manufacturers offer gutta-percha (GP) cones matching different sizes of endodontic files. The purpose of this study was to evaluate whether intra-manufacture GP diameters matched the diameters of their corresponding files at different horizontal levels of the canal. Methods and Materials: Twenty files and corresponding GP master cones of Reciproc R 40/0.08 (VDW, Munich, Germany), WaveOne Large (40/0.08) (Dentsply Maillefer, Ballaigues, Switzerland), ProTaper F3 (30/0.09) (Dentsply Maillefer, Ballaigues, Switzerland), and Mtwo (40/0.06) (VDW, Munich, Germany) were examined using laser micrometer (LSM 6000 by Mitutoyo, Japan) with accuracy of 1 nm to establish their actual diameter at D0, D1, D3 and D6. Data were analysed using the independent t-test. The differences were considered as significant for P<0.05. Results: The diameter of GP master cones was significantly larger than the corresponding files at all levels with all the above brands. ProTaper GP diameter were closest to the file diameter at D1 (GP=0.35, File=0.35 mm), and D3 (GP=0.48, file=0.49). Conclusion: This in vitro study showed that within the same manufacturer GP cone diameters do not match the diameters of their corresponding files.