Publications by authors named "Bekir Karabucak"

54 Publications

Mouse mandibular retromolar taste buds associated with a mucus salivary gland.

Chem Senses 2021 Apr 15. Epub 2021 Apr 15.

Monell Chemical Senses Center, Philadelphia, PA, USA.

We have characterized a recently rediscovered chemosensory structure at the rear of the mandibular mucosa in the mouse oral cavity originally reported in the 1980s. This consists of unorganized taste buds, not contained within troughs, associated with the ducts of an underlying minor salivary gland. Using whole-mount preparations of transgenic mice expressing green fluorescent protein under the promoter of taste-signaling-specific genes, we determined that the structure contains taste bud clusters and salivary gland orifices at the rear of each mandible, distal to the last molar and anterior to the ascending ramus. Immunohistochemical analysis show in the retromolar taste buds expression of the taste receptors Tas2R131 and T1R3 and taste cascade molecules TrpM5, PLCβ2, and GNAT3, consistent with type II taste cells, and expression of GAD1, consistent with type III taste cells. Furthermore, the neuronal marker CGRP in retromolar mucosa tissue wrapping around TrpM5+ taste buds was observed. RT-PCR showed that retromolar taste buds express all three mouse tas1r genes, 28 of the 35 tas2r genes, and taste transduction signaling genes gnat3, plcb2, and trpm5, making the retromolar TBs similar to other lingual and palate taste buds. Finally, histochemistry demonstrated that the mandibular retromolar secretory gland is a minor salivary gland of mucous type. The mandibular retromolar taste structure may thus play a role in taste sensation and represent a potential novel pharmacological target for taste disorders.
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http://dx.doi.org/10.1093/chemse/bjab019DOI Listing
April 2021

Effect of sodium hypochlorite on conventional and heat-treated nickel-titanium endodontic rotary instruments - An study.

J Dent Sci 2021 Mar 14;16(2):738-743. Epub 2020 Sep 14.

Department of Endodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, USA.

Background/purpose: Sodium hypochlorite (NaOCl) is a highly alkaline solution which exhibits antimicrobial properties. However, it causes corrosion to endodontic rotary files. This study investigated the effect of NaOCl on the metal surface of five different unused endodontic rotary files .

Materials And Methods: Two non-heat-treated nickel-titanium (NiTi) files, ProTaper, BioRace, and three heat-treated NiTi files, VortexBlue, TRUShape, and EdgeFile X7 files, were immersed in 4% NaOCl for 5, 10, and 20 min, and 1, 6 and 24 h. The corrosion susceptibility was evaluated by visual inspection and scanning electron microscopy (SEM).

Results: In the TRUShape group, the black particulate matter was mostly formed at the file's curvature and shaft. A large amount of precipitate accumulated in the EdgeFile group. The extent and prevalence of surface defects were found to be consistently higher in EdgeFile X7 instruments than in any other instruments. EdgeFile X7 and TRUShape files exhibited a greater corrosive tendency to NaOCl than BioRace, ProTaper, and VortexBlue not only under visual inspection, but also under SEM analysis after prolonged immersion (1, 6, 24 h) in 4% NaOCl. However, shorter immersion periods (5, 10, 20 min) showed little surface corrosion across all experimental groups.

Conclusion: Within the limitations of this study, EdgeFile X7 and TRUShape files exhibit greater corrosive tendencies to NaOCl than BioRace, ProTaper, and VortexBlue files after prolonged immersion in 4% NaOCl. However, shorter immersion periods, which more closely approximate clinical conditions during single root canal therapy, may not show surface corrosion across all experimental groups.
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http://dx.doi.org/10.1016/j.jds.2020.08.015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8025147PMC
March 2021

Comparison of canal transportation and centering ability of manual K-files and reciprocating files in glide path preparation: a micro-computed tomography study of constricted canals.

BMC Oral Health 2021 02 23;21(1):83. Epub 2021 Feb 23.

Department of Endodontics, School of Dental Medicine, University of Pennsylvania, 240 S 40th St, Philadelphia, PA, 19104, USA.

Background: Optimum Glide Path (OGP) is a new reciprocating motion aiming to perform efficient glide path preparation in constricted canals. The aim of this study was to investigate and compare manual and OGP movement in terms of canal transportation and centering ability in glide path preparation of constricted canals.

Methods: Thirty constricted mesial root canals of mandibular molars, with initial apical size no larger than ISO#8, were selected and negotiated with #6-#8 K-files under the microscope. Canals were randomly divided into two experimental groups: Group 1 (MAN, n = 15): Glide path was established by using #10-#15 stainless steel K-files manually; Group 2 (OGP, n = 15): #10-#15 Mechanical Glide Path super-files were used with OGP motion (OGP 90°, 300 rpm). Each instrument was used to prepare only 2 canals (as in one mesial root). Canals were scanned before and after glide path preparation with micro-computed tomography (micro-CT) to evaluate root canal transportation and centering ratio at 1, 3 and 5 mm levels from the root apex. File distortions and separations were recorded. Paired t-test was used to statistically evaluate the data (P < .05).

Results: Group 2 showed a significantly lower transportation value than group 1 at 1-mm and 3-mm levels (P < .05), however the difference at 5-mm level was not significant. There was no significant difference regarding the centering ratio between the groups. Six #10 K-files were severely distorted in group 1, while no file separation or distortion was found in group 2.

Conclusions: OGP motion performed significantly less canal transportation (apical 3 mm) and file distortion during glide path establishment in constricted canals comparing to manual motion, while the centering ability between the two was similar.

Clinical Relevance: OGP reciprocating motion provides a safer and efficient clinical approach compared to traditional manual motion in glide path establishment with small files in constricted canals.
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http://dx.doi.org/10.1186/s12903-021-01440-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7903633PMC
February 2021

Comparing the incidence of postoperative pain after root canal filling with warm vertical obturation with resin-based sealer and sealer-based obturation with calcium silicate-based sealer: a prospective clinical trial.

Clin Oral Investig 2021 Feb 8. Epub 2021 Feb 8.

Department of Endodontics, University of Pennsylvania School of Dental Medicine, 240 South 40th Street, Philadelphia, PA, 19104, USA.

Objective: This prospective clinical study compares postoperative pain after single-visit, non-surgical root canal treatment of teeth with irreversible pulpitis using two different root canal filling techniques.

Material And Methods: All cases were treated by endodontic residents with a standardized protocol (minimum apical size 35) and filled with one of the two techniques: warm vertical compaction technique (WVT) with gutta percha and epoxy resin-based sealer (AH Plus Jet Root Canal Sealer, Dentsply Maillefer, York, PA, USA) or sealer-based filling technique (SBT) with single cone gutta percha and calcium silicate-based sealer (EndoSequence BC Sealer, Brasseler, Savannah, GA, USA). Surveys were given to participating patients to record pain intensity on a numeric rating scale (NRS, 0-10) at 4, 24, and 48 h postoperatively. Statistical significance was set at 0.05 level.

Results: One hundred ninety-four surveys were distributed over eighteen months. Ninety-two patients returned the survey (41 WVT and 51 SBT), of which 38% were asymptomatic irreversible pulpitis cases. The NRS values reduced over time for both techniques. No statistical difference was found between the two groups at the three time points assessed (p > 0.05). Postoperative pain was related to age, gender, presence of preoperative pain, and sealer extrusion (p < 0.05), however not related to preoperative periapical symptoms (percussion/palpation), dental arch, root type, and experience of the provider (p > 0.05).

Conclusions: The intensity of postoperative pain for the two obturation techniques was equivalent at evaluated time points.

Clinical Relevance: The obturation technique does not influence postoperative pain. After endodontic treatment of symptomatic irreversible pulpitis teeth, the pain subsides in 48 h regardless of the technique.

Trial Registration: ClinicalTrials.gov ID: NCT04462731.
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http://dx.doi.org/10.1007/s00784-021-03814-xDOI Listing
February 2021

Response to: Problematic Conclusion.

J Endod 2020 12;46(12):1928-1929

Department of Endodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.

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http://dx.doi.org/10.1016/j.joen.2020.10.007DOI Listing
December 2020

Spectrophotometric Analysis of Coronal Tooth Discoloration Induced by Tricalcium Silicate Cements in the Presence of Blood.

J Endod 2020 Dec 17;46(12):1913-1919. Epub 2020 Sep 17.

Department of Endodontics, University of Pennsylvania School of Dental Medicine, Philadelphia, Pennsylvania.

Introduction: New tricalcium silicate cements have been shown to induce less coronal discoloration. The purpose of this in vitro study was to evaluate the degree of color change induced by various silicate materials in the presence and absence of blood.

Methods: One hundred human extracted anterior single-canal teeth were sectioned to standardized root lengths, accessed, and instrumented. Eight random experimental groups and 2 control groups were created wherein specimens were filled with experimental materials below the buccal cementoenamel junction as follows: EndoSequence RRM putty (Brasseler USA, Savannah, GA), EndoSequence RRM fast set putty (Brasseler USA), Biodentine (Septodont, Saint-Maur-des-Fossés, France), and white mineral trioxide aggregate (Dentsply Sirona, York, PA) either with the presence or absence of blood. Blood-only and saline-only samples were used for the positive and negative controls. After incubation in 100% humidity at 37°C, color changes were evaluated with a spectrophotometer (Ocean Optics, Dunedin, FL) on days 0, 30, 60, and 180 after material placement. Data were transformed into Commission International de I'Eclairage's L∗a∗b color values, and corresponding ΔE values were calculated. The 1-way analysis of variance test was performed for statistical analysis.

Results: Discoloration was observed in all specimens in the presence of blood. There was no statistical significance when comparing different materials in contact with blood. Intragroup observation at various time points, Biodentine, and EndoSequence RRM fast set putty showed significant difference between the presence and absence of blood at 180 days (P < .05).

Conclusions: Contamination with blood of tricalcium silicate materials has the potential to cause coronal tooth discoloration.
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http://dx.doi.org/10.1016/j.joen.2020.09.009DOI Listing
December 2020

Dental care during the coronavirus disease 2019 (COVID-19) outbreak: operatory considerations and clinical aspects.

Quintessence Int 2020 ;51(5):418-429

Objectives: This paper is aimed at addressing the urgent need to develop a protocol that will address the operatory and clinical aspects of dental care during the Coronavirus disease 2019 (COVID-19) outbreak.

Data Sources: The epidemiology, clinical signs and symptoms, and modes of transmission of COVID-19 are presented. This protocol was established as an international collaboration of three dental universities: Hadassah School of Dental Medicine, Israel; University of Rochester Medical Center, USA; and the University of Pennsylvania, USA. This protocol is based on a detailed review of the existing English language literature as well on the logistic and clinical experience of each facility and the opinion of the authors. The protocol is designed for a hospital setting and includes considerations related to dental treatment in both healthy subjects and those suspected or diagnosed with COVID-19. The first part of this review discusses operatory considerations; the second part discusses general dental clinical aspects; the third part discusses endodontic considerations; and the fourth part discusses surgical aspects. This protocol may be applicable to other future similar pandemics.

Conclusion: Logistic and clinical steps are required to provide dental care during the COVID-19 outbreak while preventing cross-contamination and protecting the dental team during the provision of care.
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http://dx.doi.org/10.3290/j.qi.a44392DOI Listing
April 2020

Dentists' clinical decision-making about teeth with apical periodontitis using a variable-controlled survey model in South Korea.

BMC Oral Health 2020 01 29;20(1):23. Epub 2020 Jan 29.

Microscope Center, Department of Conservative Dentistry and Oral Science Research Center, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea.

Background: This study, by using a variable-controlled survey model, sought to compare clinical decisions made by dentists with different clinical backgrounds in South Korea regarding teeth with apical periodontitis and to identify factors that influenced decision-making.

Methods: A questionnaire with 36 questions about identical patient information, clinical signs, and symptoms was filled out by participants. Each question referred to a radiograph that had been manipulated using computer software in order to control tooth-related factors. Participants were instructed to record their demographic information and choose the ideal treatment option related to each radiograph. Simple and multivariable logistic regression analyses (p < .05) were used to investigate factors related to the decision to extract the tooth. We divided factors into dentist-related factors (gender, years of experience, and professional registration) and tooth-related factors (tooth position, coronal status, root canal filling status, and size of the periapical radiolucency). Dentists were categorized into three groups, based on professional registration: general dental practitioners (GDPs), endodontists, and other specialists. Simple logistic regression analysis (p < .05) was used to evaluate the tooth-related factors influencing extraction, depending on the dentists' specialty.

Results: Participants mostly preferred saving the teeth over extraction. This preference was highest among the endodontists, followed by other specialists and GDPs. Extractions were significantly preferred for molars, teeth with previous root canal fillings, and those with apical lesions greater than 5 mm.

Conclusions: This study suggests that dentists' decision-making regarding teeth with apical periodontitis was associated with their work experience and specialty and influenced by tooth position, root canal filling status, and size of the apical lesion.

Clinical Relevance: This survey revealed that clinical decision-making related to teeth with apical periodontitis was affected by dentists' specialty and work experience and by tooth-related factors, such as tooth position, root canal filling status, and size of the apical lesion.
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http://dx.doi.org/10.1186/s12903-020-1014-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6988310PMC
January 2020

Topographic Analysis of the Isthmus in Mesiobuccal and Mesial Roots of First Molars in a South Korean Population.

Sci Rep 2020 01 27;10(1):1247. Epub 2020 Jan 27.

Microscope Center, Department of Conservative Dentistry and Oral Science Research Center, College of Dentistry, Yonsei University, Seoul, South Korea.

The purpose of this study was to evaluate the incidence and microscopic anatomy of the isthmus to provide more precise anatomical information about the mesiobuccal (MB) roots of the maxillary first molars and the mesial (M) roots of the mandibular first molars. Twenty-eight maxillary and 31 mandibular first molars were embedded, sectioned, stained, and observed at 30× magnification to evaluate the incidence and microscopic anatomy of the isthmus. The incidence of an isthmus 3 mm from the apex was 89.3% and 100% in the MB roots of the maxillary first molars and in the M roots of the mandibular first molars, respectively. The mean dentin thickness between the isthmus and the distal root surface was <1 mm at a distance of 3 mm from the apex in both types of roots. In this study, whenever two main canals were located in the MB roots of the maxillary first molars and in the M roots of the mandibular first molars, the likelihood of the presence of an isthmus increased. Therefore, clinicians should be aware of the thinnest dimensions in the distal surface of the MB roots of the maxillary first molars and the M roots of the mandibular first molars during nonsurgical and surgical root canal treatment.
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http://dx.doi.org/10.1038/s41598-020-58364-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6985258PMC
January 2020

The Role of Interleukin 6 in Osteogenic and Neurogenic Differentiation Potentials of Dental Pulp Stem Cells.

J Endod 2019 Nov 18;45(11):1342-1348. Epub 2019 Sep 18.

Department of Endodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.

Introduction: Studies have shown that there is a significantly higher concentration of interleukin 6 (IL-6) in inflamed pulp tissues compared with healthy pulp tissues. The aims of this study were to investigate the baseline differences between mesenchymal stem cells (MSCs) isolated from healthy human dental pulp stem cells (H-DPSCs) and inflamed dental pulp stem cells (I-DPSCs) and their correlation to IL-6 and to determine whether IL-6 can affect the differentiation potentials of these cells.

Methods: MSCs isolated from healthy and inflamed pulp tissues were cultured and characterized in vitro. The levels of secreted IL-6 in the culture supernatants from H-DPSCs and I-DPSCs were measured by enzyme-linked immunosorbent assay. IL-6 and neutralizing IL-6 were added to H-DPSCs and I-DPSCs, respectively. Immunofluorescence staining, alizarin red staining, and Western blotting were performed to assess the differentiation potentials of H-DPSCs and I-DPSCs. The independent unpaired 2-tailed Student's t-test was performed after quantification analysis.

Results: H-DPSCs and I-DPSCs showed a similar expression of MSC-associated markers including CD44, CD73, CD90, and CD105, whereas H-DPSCs showed a lower level of IL-6, lower osteogenic differentiation potentials, and higher neurogenic differentiation potentials compared with I-DPSCs. The addition of IL-6 to H-DPSCs increased osteogenic potentials and decreased neurogenic potentials, whereas the neutralization of IL-6 for I-DPSCs led to decreased osteogenic potentials and increased neurogenic potentials.

Conclusions: The findings of this study indicated IL-6 has the capacity to enhance osteogenesis while hindering neurogenesis of DPSCs.
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http://dx.doi.org/10.1016/j.joen.2019.08.002DOI Listing
November 2019

Catalytic antimicrobial robots for biofilm eradication.

Sci Robot 2019 04;4(29)

Biofilm Research Labs, Levy Center for Oral Health, Department of Orthodontics, School of Dental Medicine, University of Pennsylvania, USA.

Magnetically driven robots can perform complex functions in biological settings with minimal destruction. However, robots designed to damage deleterious biostructures could also have important impact. In particular, there is an urgent need for new strategies to eradicate bacterial biofilms as we approach a post-antibiotic era. Biofilms are intractable and firmly attached structures ubiquitously associated with drug-resistant infections and destruction of surfaces. Existing treatments are inadequate to both kill and remove bacteria leading to reinfection. Here we design catalytic antimicrobial robots (CARs) that precisely and controllably kill, degrade and remove biofilms with remarkable efficiency. CARs exploit iron oxide nanoparticles (NPs) with dual catalytic-magnetic functionality that (i) generate bactericidal free radicals, (ii) breakdown the biofilm exopolysaccharide (EPS) matrix, and (iii) remove the fragmented biofilm debris via magnetic field driven robotic assemblies. We develop two distinct CAR platforms. The first platform, the biohybrid CAR, is formed from NPs and biofilm degradation products. After catalytic bacterial killing and EPS disruption, magnetic field gradients assemble NPs and the biodegraded products into a plow-like superstructure. When driven with an external magnetic field, the biohybrid CAR completely removes biomass in a controlled manner, preventing biofilm regrowth. Biohybrid CARs can be swept over broad swathes of surface or can be moved over well-defined paths for localized removal with microscale precision. The second platform, the 3D molded CAR, is a polymeric soft robot with embedded catalytic-magnetic NPs, formed in a customized 3D printed mold to perform specific tasks in enclosed domains. Vane-shaped CARs remove biofilms from curved walls of cylindrical tubes, and helicoid-shaped CARs drill through biofilm clogs, while simultaneously killing bacteria. In addition, we demonstrate applications of CARs to target highly confined anatomical surfaces in the interior of human teeth. These 'kill-degrade-and-remove' CARs systems could have significant impact in fighting persistent biofilm-infections and in mitigating biofouling of medical devices and diverse surfaces.
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http://dx.doi.org/10.1126/scirobotics.aaw2388DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6748647PMC
April 2019

The Antimicrobial Effect of Bioceramic Sealer on an 8-week Matured Enterococcus faecalis Biofilm Attached to Root Canal Dentinal Surface.

J Endod 2019 Aug 31;45(8):1047-1052. Epub 2019 May 31.

Department of Endodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania. Electronic address:

Introduction: The aim of this study was to test the antibacterial activity of bioceramic sealer in comparison with AH Plus (Dentsply International Inc, York, PA) on 8-week-old Enterococcus faecalis biofilms attached to root canal surfaces using a dentin infection model.

Methods: The canal surfaces of single-rooted intact extracted teeth were infected by growing E. faecalis biofilms for 8 weeks. AH Plus sealer and EndoSequence BC Sealer (Brasseler USA, Savannah, GA) were placed on the root canal wall of the dentin specimens for 24 hours and 2 weeks in humid conditions at 37°C. Infected samples incubated with no sealers for similar periods were used as the negative controls. Specimens were labeled with fluorescent viability staining, and confocal laser scanning microscopy was used as an assessment tool of the proportions of dead and live bacteria on canal walls after exposure to root canal sealers for the determined times.

Results: EndoSequence BC Sealer killed significantly more E. faecalis in biofilm attached to the canal surfaces when compared with AH plus sealer and control at both time points (P < .05-.0005).

Conclusions: EndoSequence BC Sealer exhibited significant antimicrobial capacity in the presence of dentin for up to 2 weeks on an 8-week-old E. faecalis biofilm in comparison with AH Plus sealer.
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http://dx.doi.org/10.1016/j.joen.2019.04.004DOI Listing
August 2019

Outcome of Endodontic Microsurgery Using Mineral Trioxide Aggregate or Root Repair Material as Root-end Filling Material: A Randomized Controlled Trial with Cone-beam Computed Tomographic Evaluation.

J Endod 2019 Jul 9;45(7):831-839. Epub 2019 May 9.

Department of Endodontics, University of Pennsylvania School of Dental Medicine, Philadelphia, Pennsylvania. Electronic address:

Introduction: The purpose of this randomized clinical trial was to evaluate healing after endodontic microsurgery (EMS) using mineral trioxide aggregate (MTA) versus EndoSequence root repair material (RRM; Brasseler, Savannah, GA) as root-end filling materials.

Methods: Two hundred forty-three teeth with persistent or recurrent apical periodontitis were randomly assigned to either the MTA or RRM group. EMS was performed, and follow-up visits with clinical and radiographic investigation were scheduled at 6, 12, and 24 months with follow-up cone-beam computed tomographic (CBCT) imaging after 12 months.

Results: One hundred twenty teeth with an average follow-up of 15 months were evaluated. The overall success rate was 93.3% for periapical (PA) evaluation and 85% for CBCT evaluation. The RRM group exhibited 92% and 84% success rates as assessed on PA and CBCT imaging, respectively. The MTA group exhibited 94.7% and 86% success rates as assessed on PA and CBCT imaging, respectively. No significant difference was observed between the 2 groups. Microsurgical classification, root canal filling quality, root-end filling material depth, and root fracture were found to be significant outcome predictors.

Conclusions: EMS is a predictable procedure with successful outcome both 2-dimensional and 3-dimensional radiographic evaluation when RRM or MTA was used as the root-end filling material.
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http://dx.doi.org/10.1016/j.joen.2019.03.014DOI Listing
July 2019

Canal transportation and centering ratio after preparation in severely curved canals: analysis by micro-computed tomography and double-digital radiography.

Clin Oral Investig 2019 Dec 5;23(12):4255-4262. Epub 2019 Mar 5.

Department of Endodontics, School of Dental Medicine, University of Pennsylvania, 240 S 40th St, Philadelphia, PA, 19104, USA.

Objectives: This study compared canal transportation and centering ratio produced after instrumentation with a single heat-treated reciprocating system, WaveOne Gold (WOG; Dentsply Sirona, Tulsa, OK, USA) and a single heat-treated rotary instrument, XP-endo Shaper (XPS; FKG, La Chaux-de-Fonds, Switzerland), using micro-computed tomographic (micro-CT) imaging, and evaluated the ability of double-digital radiography (DDR) to detect canal transportation.

Materials And Methods: Mesial root canals of mandibular molars with severe curvature (25-70°) were randomly assigned to either WOG or XPS groups for preparation. Centering ratio was measured by micro-CT imaging, while canal transportation was measured by micro-CT and DDR methods at 3, 5, and 7 mm from the apex. Data were statistically compared between groups using the t test (α = 5%).

Results: The micro-CT method showed that XPS's shaping ability regarding the centering ability (P = 0.030) and canal transportation (P = 0.028) was significantly better than WOG only at the 7-mm level. The DDR technique detected no difference in canal transportation between groups at any level (P > 0.05); however, a significant difference between evaluation methods was detected at the 5-mm level in the WOG group (P = 0.023).

Conclusions: Micro-CT technique revealed a significantly better centering ability and less canal transportation with XPS compared to WOG. The DDR technique was not capable of detecting the significant difference between the tested groups.

Clinical Relevance: Root canal curvatures may lead to procedural errors during endodontic treatment. Thus, differences on the shaping ability of single heat-treated reciprocating and rotary systems should be known.
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http://dx.doi.org/10.1007/s00784-019-02870-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7737402PMC
December 2019

Stress Analyses of Retrograde Cavity Preparation Designs for Surgical Endodontics in the Mesial Root of the Mandibular Molar: A Finite Element Analysis-Part I.

J Endod 2019 Apr 1;45(4):442-446. Epub 2019 Mar 1.

Microscope Center, Department of Conservative Dentistry and Oral Science Research Center, Yonsei University College of Dentistry, Seoul, Korea; Department of Electrical & Electronic Engineering, Yonsei University College of Engineering, Seoul, Korea. Electronic address:

Introduction: The aim of this study was to investigate the influence of various apical preparation designs for surgical endodontics on stress concentrations in the mesial root of the mandibular molar under different experimental conditions using finite element analysis.

Methods: We designed 2 apical preparation groups according to whether an isthmus was present or not. Each group contained 4 subgroups according to the size of the apical preparation. We constrained the displacement of all nodes at the base of the supporting bone and applied a force of 150 N to the vertical axis. We analyzed stress generation and concentrations numerically for the groups and subgroups.

Results: In the subgroups, the von Mises and maximum principal stresses reduced gradually according to the enlargement of the prepared cavity. However, when the preparation extended excessively in the isthmus preparation groups, the situation reversed (ie, both von Mises and maximum principal stresses increased).

Conclusions: Within the limitations of this study, the apical preparation design influenced the distribution of stress concentration. Unlike the overall pattern in which stress decreased as the amount of apical preparation increased, stress increased when the amount of residual dentin was extremely thin.
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http://dx.doi.org/10.1016/j.joen.2019.01.001DOI Listing
April 2019

Do buffered local anesthetics provide more successful anesthesia than nonbuffered solutions in patients with pulpally involved teeth requiring dental therapy?: A systematic review.

J Am Dent Assoc 2019 03;150(3):165-177

Background: The authors conducted a systematic review that addresses the following population, intervention, comparison, outcome question: "In adults requiring dental therapy with pulpally involved teeth, what is the comparative efficacy of buffered local anesthetics (LAs) compared with that of nonbuffered LAs in achieving anesthetic success?"

Types Of Studies Reviewed: The authors searched MEDLINE, Scopus, Cochrane Library, ClinicalTrials.gov, World Health Organization International Trials Registry Platform, OpenGrey, Google Scholar Beta, and 2 textbooks to identify double-blinded randomized controlled trials in which researchers directly compared the efficacy of buffered and nonbuffered LAs in adult participants, as well as any associated side effects. Furthermore, they checked the reference lists of all included and excluded studies to identify any further trials. Weighted anesthesia success rates were estimated and compared by using a random-effects model.

Results: A total of 14,011 studies were initially identified from the search; 5 double-blinded randomized clinical trials met inclusion criteria. Buffered LAs were more likely to achieve successful anesthesia than nonbuffered LAs (odds ratio, 2.29; 95% confidence interval, 1.11 to 4.71; P = .0232; I = 66%).

Conclusions And Practical Implications: This investigation revealed that buffered LAs are more effective than nonbuffered LAs when used for mandibular or maxillary anesthesia in pulpally involved teeth. Buffering of LAs has 2.29 times greater likelihood of achieving successful anesthesia.
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http://dx.doi.org/10.1016/j.adaj.2018.11.007DOI Listing
March 2019

Outcome of Crown and Root Resection: A Systematic Review and Meta-analysis of the Literature.

J Endod 2019 Jan 6;45(1):6-19. Epub 2018 Dec 6.

Department of Endodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.

Introduction: A systematic review and meta-analysis were conducted to report combined and individual weighted pooled outcome rates for crown resection (CR) and root resection (RR) procedures.

Methods: Three electronic databases (PubMed [MEDLINE], Scopus, and the Cochrane Library) were searched to identify human studies in 12 languages on CR (hemisection, trisection, and premolarization) and RR (amputations and RRs without removal of crown portions). Five peer-reviewed journals, references of relevant publications, and reviews were hand searched. Assessment by 3 independent reviewers was based on the following predefined Population, Intervention, Comparison, Outcome, Study Design question: "For teeth in patients undergoing surgical therapy by CR versus RR, what is the expected probability of survival according to longitudinal studies with strictly defined outcome measurements and inclusion/exclusion criteria?" Clinical investigations with at least 12 months of follow-up were included. Studies and level of evidence were appraised using the Newcastle-Ottawa Scale and Grading of Recommendations, Assessment, Development and Evaluations.

Results: Thirty-four articles were obtained for final analysis. Data could be extracted from 19 studies (CR and RR OVERALL: N = 2667 [19 studies], CR: n = 111 [3 studies], and RR: n = 1127 [9 studies]). A random effects model showed weighted mean survival rates of 85.6% (95% confidence interval [CI], 76.7-91.5) for CR and RR procedures OVERALL. Individual data showed weighted mean survival rates of 81.9% (95% CI, 72.0-88.8) for CR and 87.2% (95% CI, 71.7-94.8) for RR. There was no statistically significant difference between CR and RR (P = .89, odds ratio calculation) or between maxillary and mandibular molars (P = .81, Fisher exact test).

Conclusions: Overall, CR and RR procedures showed good outcome rates. Large-scale randomized controlled trials should be conducted to strengthen the evidence.
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http://dx.doi.org/10.1016/j.joen.2018.10.003DOI Listing
January 2019

Outcome of Endodontic Surgery: A Meta-analysis of the Literature-Part 3: Comparison of Endodontic Microsurgical Techniques with 2 Different Root-end Filling Materials.

J Endod 2018 Jun 19;44(6):923-931. Epub 2018 Apr 19.

Department of Endodontics, University of Pennsylvania School of Dental Medicine, Philadelphia, Pennsylvania.

Introduction: The aim of the present study was to investigate the influence of root-end preparation and filling material on endodontic surgery outcome. A systematic review and meta-analysis was conducted to determine the outcome of resin-based endodontic surgery (RES, the use of high-magnification preparation of a shallow and concave root-end cavity and bonded resin-based root-end filling material) versus endodontic microsurgery (EMS, the use of high-magnification ultrasonic root-end preparation and root-end filling with SuperEBA [Keystone Industries, Gibbstown, NJ], IRM [Dentsply Sirona, York, PA], mineral trioxide aggregate [MTA], or other calcium silicate cements).

Methods: An exhaustive literature search was conducted to identify prognostic studies on the outcome of root-end surgery. Human studies conducted from 1966 to the end of December 2016 in 5 different languages (ie, English, French, German, Italian, and Spanish) were searched in 4 electronic databases (ie, Medline, Embase, PubMed, and Cochrane Library). Relevant review articles on the subject were scrutinized for cross-references. In addition, 5 dental and medical journals (Journal of Endodontics; International Endodontic Journal; Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontics; Journal of Oral and Maxillofacial Surgery; and International Journal of Oral and Maxillofacial Surgery) were hand checked dating back to 1975. All abstracts were screened by 3 independent reviewers (H.B., M.K., and F.S.). Strict inclusion-exclusion criteria were defined to identify relevant articles. Raw data were extracted from the full-text review of these selected articles independently by each of the 3 reviewers. In case of disagreement, an agreement was reached by discussion, and qualifying articles were assigned to group RES. For EMS, the same search strategy was performed for the time frame October 2009 to December 2016, whereas up to October 2009 the data were obtained from a previous systematic review with identical criteria and search strategy. Weighted pooled success rates and a relative risk assessment between RES and EMS were calculated. To make a comparison between groups, a random effects model was used.

Results: Sixty-eight articles were eligible for full-text review. Of these, per strict inclusion exclusion criteria, 14 studies qualified, 3 for RES (n = 862) and 11 for EMS (n = 915). Weighted pooled success rates for RES were 82.20% (95% confidence interval [CI], 0.7965-0.8476) and 94.42% for EMS (95% CI, 0.9295-0.9590). This difference was statistically significant (P < .0005).

Conclusions: The probability for success for EMS proved to be significantly greater than the probability for success for RES, providing best available evidence on the influence of cavity preparation with ultrasonic tips and/or SuperEBA (Keystone Industries, Gibbstown, NJ), IRM (Dentsply Sirona, York, PA), MTA, or silicate cements as root-end filling material instead of a shallow cavity preparation and placement of a resin-based material. Additional large-scale randomized clinical trials are needed to assess other predictors of outcome.
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http://dx.doi.org/10.1016/j.joen.2018.02.021DOI Listing
June 2018

Novel Endodontic Disinfection Approach Using Catalytic Nanoparticles.

J Endod 2018 May 14;44(5):806-812. Epub 2018 Feb 14.

Divisions of Pediatric Dentistry and Community Oral Health, Department of Orthodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.

Introduction: The aim of this study was to test a new disinfection technology using biomimetic iron oxide nanoparticles (IO-NPs) with peroxidaselike activity to enhance antibacterial activity on root canal surfaces and in dentinal tubules.

Methods: The canal surfaces and dentinal tubules of single-rooted intact extracted teeth were infected by growing Enterococcus faecalis biofilms for 3 weeks. The samples were divided into 6 treatment groups: (1) phosphate-buffered saline (PBS) (negative control), (2) 3% hydrogen peroxide (HO) (test control), (3) IO-NPs (0.5 mg/mL) (test control), (4) IO-NPs (0.5 mg/mL) + 3% HO, (5) 3% sodium hypochlorite (positive control), and (6) 2% chlorhexidine (positive control). Environmental scanning electron microscopy coupled with energy-dispersive spectroscopy was used to confirm IO-NPs binding to the canal surface after a single treatment. Specimens were labeled with fluorescent staining for live/dead cells, and confocal laser scanning microscopy was used for the quantification of dead bacteria relative to the negative control (PBS).

Results: Both biofilm formation and dentinal tubule infection were successfully recapitulated using the in vitro model. IO-NPs were capable of binding to the infected canal surfaces despite a single, short-term (5-minute) treatment. IO-NP activation of HO killed significantly more E. faecalis present on the canal surfaces and at different depths of dentinal tubules when compared with all other experimental groups (P < .05-.0005).

Conclusions: The results reveal the potential to exploit nanocatalysts with enzymelike activity as a potent alternative approach for the treatment of endodontic infections.
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http://dx.doi.org/10.1016/j.joen.2017.12.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6190715PMC
May 2018

Computer-aided Design/Computer-aided Manufacturing-guided Endodontic Surgery: Guided Osteotomy and Apex Localization in a Mandibular Molar with a Thick Buccal Bone Plate.

J Endod 2018 Apr 19;44(4):665-670. Epub 2018 Jan 19.

Microscope Center, Department of Conservative Dentistry and Oral Science Research Center, Yonsei University College of Dentistry, Seoul, Korea. Electronic address:

A mandibular molar with a thick buccal bone plate is a challenging problem in endodontic surgery despite the increase in the success rate of endodontic surgery nowadays. This report describes the application of a surgical template to guide osteotomy and facilitate apex localization in a mandibular molar with a thick buccal bone plate. A 57-year-old woman visited the authors' clinic for pain in tooth 19 and was diagnosed with symptomatic apical periodontitis in this previously treated tooth. Nonsurgical retreatment was performed; however, 2 years later, the patient reported pain in the same tooth. A periapical lesion was confirmed using cone-beam computed tomographic (CBCT) imaging, and endodontic surgery on the mesial root of tooth 19 was planned. After CBCT imaging and cast scan data were transferred to implant surgical planning software, the data were superimposed. In the superimposed model, an anchor pin was designed to target the mesial root apex of tooth 19. The surgical template was then printed using a 3-dimensional printer. Endodontic microsurgery included application of this printed surgical template. A computer-aided design/computer-aided manufacturing (CAD/CAM)-guided surgical template minimized the extent of osteotomy and enabled precise targeting of the apex in this case. There were no postoperative complications. A CAD/CAM-guided surgical template is useful in endodontic surgery for complicated cases.
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http://dx.doi.org/10.1016/j.joen.2017.12.009DOI Listing
April 2018

Long-term Evaluation of Treatment Planning Decisions for Nonhealing Endodontic Cases by Different Groups of Practitioners.

J Endod 2018 Feb 16;44(2):226-232. Epub 2017 Dec 16.

Department of Endodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania. Electronic address:

Introduction: The aim of this study was to investigate changes in treatment planning decisions among different practitioner groups over 7 years for teeth with apical periodontitis and a history of endodontic treatment.

Methods: A Web-based survey was sent to dentists in Pennsylvania in 2009 consisting of 14 cases with nonhealing periapical lesions and intact restorations without evidence of recurrent caries. Participants selected among 5 treatment options: wait and observe, nonsurgical retreatment (NSRTX), surgical retreatment (SRTX), extraction and fixed partial denture, or extraction and implant (EXIMP). In 2016, the identical survey was resent to the original 2009 participants.

Results: In 2009, 262 dentists participated in the survey. Two hundred one participants were general practitioners (GPs: 76.7%), 26 endodontists (ENDOs: 9.9%), and 35 other specialists (prosthodontics, periodontics, and oral surgery [SPECs]: 13.4%) (n = 262). EXIMP, NSRTX, and SRTX were fairly equally selected but with great variation between practitioner groups (χ = 173.49, P < .05). A subset group of 104 participants (SUB) (39.7% of the original participants) retook the survey in 2016 (69 GPs [66.3%], 15 ENDOs [14.0%], and 20 SPECs [19.7%]). Comparisons among practitioner groups were significantly different in SUB (n = 104) for 2009 (χ = 95.536, P < .05) and 2016 (χ = 109.8889, P < .05). Intragroup reliability between 2009 and 2016 revealed no significant differences between the overall treatment planning choices for all practitioners (GPs, ENDOs, or SPECs). Intrapractitioner reliability showed many treatment planning decision changes on an individual level. Chances that individuals changed their original decision were 47.8% (95% confidence interval, 45.2%-50.4%) and were significantly different among the 3 practitioner groups (GPs > SPECs > ENDOs [χ = 11.2792, P < .05]). No significant changes were observed in the decision for tooth saving versus replacement treatment options (P = .520).

Conclusions: No significant differences were noted between current and past treatment planning decisions in regard to tooth preservation by endodontic retreatment versus tooth extraction and replacement. However, individual practitioners lacked consistency in their decision making over time.
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http://dx.doi.org/10.1016/j.joen.2017.09.004DOI Listing
February 2018

Methodological Quality Assessment of Meta-analyses in Endodontics.

J Endod 2018 Jan 9;44(1):22-31. Epub 2017 Oct 9.

Department of Endodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania. Electronic address:

Introduction: The objectives of this review were to assess the methodological quality of published meta-analyses related to endodontics using the assessment of multiple systematic reviews (AMSTAR) tool and to provide a follow-up to previously published reviews.

Methods: Three electronic databases were searched for eligible studies according to the inclusion and exclusion criteria: Embase via Ovid, The Cochrane Library, and Scopus. The electronic search was amended by a hand search of 6 dental journals (International Endodontic Journal; Journal of Endodontics; Australian Endodontic Journal; Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology; Endodontics and Dental Traumatology; and Journal of Dental Research). The searches were conducted to include articles published after July 2009, and the deadline for inclusion of the meta-analyses was November 30, 2016. The AMSTAR assessment tool was used to evaluate the methodological quality of all included studies.

Results: A total of 36 reports of meta-analyses were included. The overall quality of the meta-analyses reports was found to be medium, with an estimated mean overall AMSTAR score of 7.25 (95% confidence interval, 6.59-7.90). The most poorly assessed areas were providing an a priori design, the assessment of the status of publication, and publication bias.

Conclusions: In recent publications in the field of endodontics, the overall quality of the reported meta-analyses is medium according to AMSTAR.
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http://dx.doi.org/10.1016/j.joen.2017.07.019DOI Listing
January 2018

A Survey of Cone-beam Computed Tomographic Use among Endodontic Practitioners in the United States.

J Endod 2017 May 11;43(5):699-704. Epub 2017 Mar 11.

Department of Endodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.

Introduction: Cone-beam computed tomographic (CBCT) imaging is an emerging technology for clinical endodontic practice. The aim of this study was to investigate the acceptance, accessibility, and usage of CBCT imaging among American Association of Endodontists members in the United States by means of an online survey.

Methods: An invitation to participate in a web-based survey was sent to 3076 members of the American Association of Endodontists. The survey consisted of 8 questions on demographics, access to CBCT machines, field of view (FOV), frequency of use for particular applications, and reasons in case CBCT was not used.

Results: A total of 1083 participants completed the survey, giving an overall completed response rate of 35.2%; 80.30% of the participants had access to a CBCT scan, of which 50.69% (n = 443) were on-site and 49.31% (n = 431) were off-site, and 19.30% of all respondents denied having access to CBCT imaging. Limited FOV was used by 55.26% participants, 22.37% used larger FOV formats, and the remaining 22.37% were not sure about the format. There was a significantly greater usage of CBCT technology in residency programs (n = 78/84 [92.86%]) compared with practitioners who had finished an endodontic specialty program (n = 796/999 [79.68%]) (χ = 10.30, P = .02). Practitioners used CBCT imaging "frequent" or "always" for internal or external resorptions (47.28%), preoperatively for surgical retreatment or intentional replantation (45.34%), missing canals (25.39%), preoperatively for nonsurgical retreatments (24.91%), differential diagnosis (21.16%), identifying periradicular lesions (18.26%), calcified cases (13.54%), immature teeth (4.71%), and to assess healing (3.87%). There was a significant difference in on-site and off-site CBCT imaging use for any of these applications (P < .001). Prevalent reasons for not using CBCT technology were cost (53.79%) and lack of installation space (8.29%). General concerns were expressed about resolution limitations, radiation exposure, and cost to the patient.

Conclusions: There is a widespread application of CBCT technology in endodontic practice; however, results from the survey also confirmed that the benefit versus risk ratio should always be in favor of the patient if CBCT scans are taken.
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http://dx.doi.org/10.1016/j.joen.2016.12.021DOI Listing
May 2017

Outcome of Revascularization Procedure: A Retrospective Case Series.

J Endod 2016 Dec 7;42(12):1752-1759. Epub 2016 Oct 7.

Department of Endodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania. Electronic address:

Introduction: The purpose of this retrospective case series was to investigate the outcome of the revascularization procedure in necrotic immature teeth.

Methods: The residents and faculty members at the University of Pennsylvania endodontic department were invited to submit consecutive revascularization cases treated by them, irrespective of the outcome, during the time period of 2009 to 2012. Twenty-eight of 35 submitted necrotic immature teeth met the inclusion criteria. The treatment protocol included minimal instrumentation and irrigation with 3% sodium hypochlorite and 17% EDTA. Triple antibiotic paste was placed for a minimum of 21 days. After blood clot induction, either EndoSequence Bioceramic Putty (Brasseler, Savannah, GA) or mineral trioxide aggregate was placed below the cementoenamel junction, and composite was used as a final restoration. The follow-up period ranged from 7 to 72 months. The outcome was assessed as complete healing (the absence of clinical signs and symptoms, complete resolution of periradicular radiolucency, increase in the root dentin thickness/length, and apical closure), incomplete healing (the absence of clinical signs and symptoms, the periapical lesion completely healed without any signs of root maturation or thickening, the periapical lesion either reduced in size or unchanged with/without radiographic signs of increasing root dentin thickness/length, or apical closure), and failure (persistent clinical signs and symptoms and/or increased size of the periradicular lesion).

Results: Twenty-one of 28 cases (75%) healed completely, 3 cases (10.7%) failed during the observation period and needed further treatment, and 4 cases (14%) presented with incomplete healing.

Conclusions: Within the limitation of this study, the outcome of revascularization, wherein healing of periapical periodontitis and maturation of roots occurs, is fairly high, making it a viable treatment option in comparison with apexification.
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http://dx.doi.org/10.1016/j.joen.2016.06.021DOI Listing
December 2016

Biocompatibility of two experimental scaffolds for regenerative endodontics.

Restor Dent Endod 2016 May 28;41(2):98-105. Epub 2016 Mar 28.

Department of Endodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA.

Objectives: The biocompatibility of two experimental scaffolds for potential use in revascularization or pulp regeneration was evaluated.

Materials And Methods: One resilient lyophilized collagen scaffold (COLL), releasing metronidazole and clindamycin, was compared to an experimental injectable poly(lactic-co-glycolic) acid scaffold (PLGA), releasing clindamycin. Human dental pulp stem cells (hDPSCs) were seeded at densities of 1.0 × 10(4), 2.5 × 10(4), and 5.0 × 10(4). The cells were investigated by light microscopy (cell morphology), MTT assay (cell proliferation) and a cytokine (IL-8) ELISA test (biocompatibility).

Results: Under microscope, the morphology of cells coincubated for 7 days with the scaffolds appeared healthy with COLL. Cells in contact with PLGA showed signs of degeneration and apoptosis. MTT assay showed that at 5.0 × 10(4) hDPSCs, COLL demonstrated significantly higher cell proliferation rates than cells in media only (control, p < 0.01) or cells co-incubated with PLGA (p < 0.01). In ELISA test, no significant differences were observed between cells with media only and COLL at 1, 3, and 6 days. Cells incubated with PLGA expressed significantly higher IL-8 than the control at all time points (p < 0.01) and compared to COLL after 1 and 3 days (p < 0.01).

Conclusions: The COLL showed superior biocompatibility and thus may be suitable for endodontic regeneration purposes.
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http://dx.doi.org/10.5395/rde.2016.41.2.98DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4868884PMC
May 2016

Prevalence of Apical Periodontitis in Endodontically Treated Premolars and Molars with Untreated Canal: A Cone-beam Computed Tomography Study.

J Endod 2016 Apr 10;42(4):538-41. Epub 2016 Feb 10.

Department of Endodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.

Introduction: The purpose of this retrospective cohort study was to evaluate the incidence of missed canals in endodontically treated teeth in the Greater Philadelphia area patient population and to evaluate the effect of untreated canals on endodontic outcome.

Methods: A total of 1397 cone-beam computed tomography (CBCT) volumes taken from January 2013 to July 2015 were investigated. Limited view CBCT images were taken with Kodak 9000 3D System field of view at voxel size, 76 μm or Morita Veraviewpocs 3D F40 field of view at voxel size, 125 μm. All root canal-treated premolars and molars were included in the study. Unfilled canals appearing from cementoenamel junction to apex including splitting from a main canal at coronal, mid, or apical third were defined as missed-untreated canal. A periapical lesion was diagnosed when disruption of the lamina dura was detected and the low density area associated with the radiographic apex was at least twice the width of the periodontal ligament space.

Results: The overall incidence of missed canals was 23.04%. The incidence of missed canals per tooth was highest in tooth #14 at 46.5% and tooth #3 at 41.3%. The incidence of missed canals was highest in the upper molars at 40.1% and lowest in the upper premolars at 9.5%. There was a significant difference in lesion prevalence when a canal was missed-untreated (P < .05). Teeth with a missed canal were 4.38 times more likely to be associated with a lesion.

Conclusions: Limited field-of-view CBCT should be examined before any endodontic retreatment to identify missed canals. This knowledge would not only help clinicians to locate missed canals clinically but would also help in deciding the surgical approach.
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http://dx.doi.org/10.1016/j.joen.2015.12.026DOI Listing
April 2016

Does Para-chloroaniline Really Form after Mixing Sodium Hypochlorite and Chlorhexidine?

J Endod 2016 Mar 29;42(3):455-9. Epub 2016 Jan 29.

Department of Endodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.

Introduction: Mixing sodium hypochlorite (NaOCl) with chlorhexidine (CHX) forms a brown-colored precipitate. Previous studies are not in agreement whether this precipitate contains para-chloroaniline (PCA). Tests used for analysis may demonstrate different outcomes. Purpose of this study was to determine whether PCA is formed through the reaction of mixing NaOCl and CHX by using high performance liquid chromatography, proton nuclear magnetic resonance spectroscopy, gas chromatography, thin layer chromatography, infrared spectroscopy, and gas chromatography/mass spectrometry.

Methods: To obtain a brown precipitate, 4.99% NaOCl was mixed with 2.0% CHX. This brown precipitate was analyzed and compared with signals obtained from commercially available 4.99% NaOCl, 2% solutions, and 98% PCA in powder form.

Results: Chromatographic and spectroscopic analyses showed that brown precipitate does not contain free PCA.

Conclusions: This study will be a cutoff proof for the argument on PCA formation from reaction of CHX and NaOCl.
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http://dx.doi.org/10.1016/j.joen.2015.12.024DOI Listing
March 2016

Spectrophotometric Analysis of Coronal Tooth Discoloration Induced by Various Bioceramic Cements and Other Endodontic Materials.

J Endod 2015 Nov 18;41(11):1862-6. Epub 2015 Sep 18.

From the Department of Endodontics, University of Pennsylvania School of Dental Medicine, Philadelphia, Pennsylvania.

Introduction: Coronal tooth discoloration induced by various endodontic materials was evaluated in vitro.

Methods: Eighty extracted human maxillary anterior teeth were accessed, instrumented, and sectioned to standardized root lengths of 10 mm below the cementoenamel junction. Pulp chambers were cleaned chemomechanically to ensure complete tissue removal. Specimens were filled with experimental materials in 8 random groups: RRM, EndoSequence RRM putty (Brasseler, Savannah, GA); RRMF, EndoSequence RRM fast set paste (Brasseler); BD, Biodentine (Septodont, Saint-Maur-des-Fossés, France); WMTA, white MTA (Dentsply, York, PA), GMTA, gray MTA (Dentsply); AH+, AH Plus sealer (Dentsply); TAP, triple antibiotic paste (metronidazole, ciprofloxacin, and minocycline); and NF, no filling (negative control group). After incubation in 100% humidity at 37°C, color changes were evaluated with a spectrophotometer (Ocean Optics, Dunedin, FL) on days 0, 7, 30, 60, and 180 after material placement (T0-T180). Data were transformed into Commission International de I'Eclairage's L*a*b color values, and corresponding ΔE values were calculated. Two-way analysis of variance and the Bonferroni method were performed.

Results: Visual discoloration was observed in all specimens in the GMTA, WMTA, and TAP groups at T7, increasing with time. The ΔE value between the initial color at T0 and at T7, T30, T60, and T180 was significantly different for GMTA, WMTA, and TAP (P < .001). ΔE values for the BD, RRM, RRMF, AH+, and NF groups were not statistically significantly different between T0 and T7, T30, T60, and T180, respectively, except for 3 samples below the human perceptible threshold. Values of L* dropped significantly from T0 to T180 in the TAP, GMTA, and WMTA groups.

Conclusions: Significant coronal tooth discoloration was caused by TAP, GMTA, and WMTA but not by BD, RRM, and RRMF.
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http://dx.doi.org/10.1016/j.joen.2015.07.003DOI Listing
November 2015

Healing after root-end microsurgery by using mineral trioxide aggregate and a new calcium silicate-based bioceramic material as root-end filling materials in dogs.

J Endod 2015 Mar 14;41(3):389-99. Epub 2015 Jan 14.

Department of Endodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.

Introduction: The purpose of this study was to compare healing after root-end surgery by using grey mineral trioxide aggregate (MTA) and EndoSequence Root Repair Material (RRM) as root-end filling material in an animal model.

Methods: Apical periodontitis was induced in 55 mandibular premolars of 4 healthy beagle dogs. After 6 weeks, root-end surgeries were performed by using modern microsurgical techniques. Two different root-end filling materials were used, grey MTA and RRM. Six months after surgery, healing of the periapical area was assessed by periapical radiographs, cone-beam computed tomography (CBCT), micro computed tomography (CT), and histology.

Results: Minimal or no inflammatory response was observed in the majority of periapical areas regardless of the material. The degree of inflammatory infiltration and cortical plate healing were not significantly different between the 2 materials. However, a significantly greater root-end surface area was covered by cementum-like, periodontal ligament-like tissue, and bone in RRM group than in MTA group. When evaluating with periapical radiographs, complete healing rate in RRM and MTA groups was 92.6% and 75%, respectively, and the difference was not statistically significant (P = .073). However, on CBCT and micro CT images, RRM group demonstrated significantly superior healing on the resected root-end surface and in the periapical area (P = .000 to .027).

Conclusions: Like MTA, RRM is a biocompatible material with good sealing ability. However, in this animal model RRM achieved a better tissue healing response adjacent to the resected root-end surface histologically. The superior healing tendency associated with RRM could be detected by CBCT and micro CT but not periapical radiography.
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http://dx.doi.org/10.1016/j.joen.2014.11.005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4415855PMC
March 2015