Publications by authors named "Mahmoud Torabinejad"

84 Publications

Clinical and Histological Evaluation of Tissue Healing in Beveled or Perpendicular Vertical Releasing Incision.

J Endod 2021 Oct 9;47(10):1625-1630. Epub 2021 Jul 9.

Loma Linda University, School of Dentistry, Loma Linda, California.

Objectives: The aim of this investigation was to evaluate the clinical and histological differences in wound healing between beveled and perpendicular vertical releasing incisions in dogs.

Material And Methods: Four male mongrel dogs were used in this investigation. In each quadrant, a vertical releasing incision was made on either the mesial or the distal aspect of the cuspid teeth of each animal all on the same day. The sites were randomly selected to either receive a beveled incision or a perpendicular incision. A sulcular muco-periosteal flap was raised, reapproximated, and then sutured using 3-0 Vicryl. The animals were evaluated daily for the first week, and then at different time intervals during this investigation. One animal was killed at each time interval of 9, 14, 21, and 28 days after surgery. One animal was killed at each time interval, and a bone block consisting of the cuspid teeth and their surrounding bone and soft tissues was harvested, formalin fixed, and paraffin embedded. Samples were sectioned serially and stained with hematoxylin-eosin. Specimens were evaluated using a microscope with magnification ranging from ×10 to ×400 by a histopathologist. Four indices were used for histologic evaluation.

Results: At day 9 after surgery, a visible groove was seen in the marginal tissues of both perpendicular and beveled incisions. At day 9, both of the histologic sections showed less organized connective tissue and capillary networks with no significant difference in inflammation. In the 14-day samples, a depression was still present at the perpendicular incision sites, but not in the beveled incision group, where the groove was not visualized at all. In the 21- and 28-day samples, irregular capillary arrangements were seen in the connective tissue of the perpendicular incision groups with completely healed epithelium. There were no statistically significant differences noted histologically between the beveled and perpendicular incision groups noted at 9, 14, 21, or 28 days (P > .05).

Conclusion: Based on these findings, it appears that clinical and histologic healing of beveled or perpendicular releasing incisions are similar 28 days after surgery.
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http://dx.doi.org/10.1016/j.joen.2021.07.005DOI Listing
October 2021

Henry John Van Hassel, DDS, MSD, PhD, 1933-2020: A Pioneer Research Icon.

J Endod 2021 05 27;47(5):684-689. Epub 2021 Feb 27.

Department of Endodontics, School of Dentistry, University of Washington, Seattle, Washington.

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http://dx.doi.org/10.1016/j.joen.2021.02.007DOI Listing
May 2021

Regeneration of Pulp-Dentin Complex in a Tooth with Symptomatic Irreversible Pulpitis and Open Apex Using Regenerative Endodontic Procedures.

J Endod 2021 Feb 10;47(2):247-252. Epub 2020 Oct 10.

Division of Endodontics, Department of Preventative and Restorative Dental Sciences, Loma Linda University School of Dentistry, Loma Linda, California.

Regenerative endodontic procedures are undertaken on permanent teeth with necrotic pulps and open apices in an attempt to resolve symptoms, to allow the continued development of the root(s), and to reestablish vitality. The available histologic analysis of these teeth has, in the majority of studies, shown that true regeneration of the pulp-dentin complex is not achieved. A recent investigation using an animal model outlined a procedure wherein pulpal amputation a few millimeters short of the apex followed by evoked bleeding allowed the complete regeneration of the normal pulp-dentin complex in immature vital teeth of ferrets. By implementation of this procedure, we report successful pulp regeneration outcome evidenced by continued root development and a positive response to pulp vitality tests in a maxillary central incisor with an open apex diagnosed with symptomatic irreversible pulpitis.
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http://dx.doi.org/10.1016/j.joen.2020.09.021DOI Listing
February 2021

Improving pulp revascularization outcomes with buccal fat autotransplantation.

J Tissue Eng Regen Med 2020 09 16;14(9):1227-1235. Epub 2020 Aug 16.

Department of Oral and Maxillofacial Pathology and Dental Implant Research Center, Dental Research Institute, Isfahan University of Medical Sciences, Isfahan, Iran.

Several techniques have been introduced to improve the pulp revascularization outcomes. The use of the tissue graft can create more practical tissue regeneration, provide vascular supply, and enhance tissue healing. The aim of the present study was to investigate the histologic and molecular outcomes of pulp revascularization with buccal fat autotransplantation. Fifty-six open apex roots from four dogs aged 4-6 months were randomly allocated to five groups of endodontic regeneration models: Group 1 (negative control, n = 4); Group 2 (control and without intervention, n = 4); Group 3 (blood clot, n = 16); Group 4 (buccal fat autotransplantation, n = 16); and Group 5 (blood clot plus buccal fat autotransplantation, n = 16). After 3 months, the extracted dog teeth were analyzed by histological and immunohistochemical techniques. Furthermore, real-time quantitative polymerase chain reactions were implemented to assess the gene expression profiles of dentin sialophosphoprotein (DSPP), dentin matrix protein (DMP), collagen I (COL1), and alkaline phosphatase (ALP) on regenerated tissue in the root canals. There were no significant differences in the severity of inflammation and necrosis between intervention groups. Immunohistochemical analysis showed significant differences among the study groups in expression level of extracellular glycoproteins such as fibronectin, laminin, and tenascin C. Group 5 showed an increase in the expression of DMP1 and COL1 genes. The expression of DSPP gene increased significantly in Group 4. The expression of ALP gene increased significantly in Group 3. Using this procedure may open new fields of research for regenerative endodontic procedure in which tissue autotransplant, particularly adipose tissue, may improve the outcomes of pulp revascularization.
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http://dx.doi.org/10.1002/term.3094DOI Listing
September 2020

Regenerative Endodontic Treatment in Immature Noninfected Ferret Teeth Using Blood Clot or SynOss Putty as Scaffolds.

J Endod 2020 Feb 16;46(2):209-215. Epub 2019 Dec 16.

Advanced Specialty Education Programs in Endodontics, School of Dentistry, Loma Linda University, Loma Linda, California.

Introduction: SynOss Putty (Collagen Matrix, Oakland, NJ) has shown the formation of mineralized tissues when used as a scaffold in regenerative endodontic treatment (RET) in immature human teeth. The aim of this study was to compare the outcome of RET in immature ferret teeth using 2 scaffolds: a blood clot and SynOss Putty.

Methods: Thirty-two immature canine teeth in 8 ferrets (95-105 days old) were divided into 4 groups: group 1, no treatment (positive control, n = 8); group 2, full pulpectomy with no further treatment (negative control, n = 8); group 3, revascularization using a blood clot (n = 8); and group 4, revascularization using a SynOss Putty scaffold (n = 8). After 3 months, the animals were euthanized, and the newly formed tissues were examined histologically. The data were statistically analyzed using chi-square and Fisher exact tests.

Results: Normal pulps were found in group 1. No pulp tissue was found in teeth in group 2. In group 3, the pulp tissue and the odontoblastic layer were absent, and the root canal spaces were filled with a hard tissue characterized as bonelike and cementumlike tissues. All teeth except 1 in group 4 showed no hard tissue formation and intracanal/periapical inflammation. SynOss Putty was significantly associated with a lack of tissue formation and intracanal/periapical inflammation (P < .05).

Conclusions: Intracanal hard tissue formation was observed in immature teeth after RET using a blood clot. No tissue regeneration was found in the majority of samples using SynOss Putty as a scaffold.
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http://dx.doi.org/10.1016/j.joen.2019.10.029DOI Listing
February 2020

A Retrospective Comparison of Outcome in Patients Who Received Both Nonsurgical Root Canal Treatment and Single-tooth Implants.

J Endod 2019 Feb;45(2):99-103

School of Dentistry, Loma Linda University School of Dentistry, Loma Linda, California.

Introduction: Currently, no study has compared the outcome of nonsurgical root canal treatment (NSRCT) and single-tooth implants (STIs) provided to the same patient. The purpose of this study was to determine if the survival outcome of the 2 treatment modalities is different.

Methods: The medical/dental records of 3671 patients with at least 1 STI and 1 NSRCT were reviewed. One hundred seventy patients with at least a 5-year follow-up were included. The survival outcome of NSRCT and STI and related factors were evaluated.

Results: Both treatments had a 95% survival rate with a mean 7.5-year follow-up. Most preoperative and postoperative factors involved in both procedures had no significant effect on the treatment outcomes. The number of adjunct and additional treatments, the number of appointments, the elapsed time before the final restoration, the number of prescribed medications, and the cost of the treatment were significantly higher for STI in comparison with NSRCT.

Conclusions: Both NSRCT and STI are highly successful treatments. Compromised teeth that could otherwise be saved by NSRCTs and deemed restorable should not routinely be treatment planned for STI.
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http://dx.doi.org/10.1016/j.joen.2018.10.018DOI Listing
February 2019

Clinical, Radiographic, and Histologic Outcome of Regenerative Endodontic Treatment in Human Teeth Using a Novel Collagen-hydroxyapatite Scaffold.

J Endod 2019 Feb;45(2):136-143

Torabinejad Institute of Surgical Education and Research Venues, Irvine, California.

Introduction: Histologic examination of teeth after regenerative endodontic treatment (RET) shows that the type, quality, and quantity of tissues formed in the root canal space are not predictable. The aim of this study was to examine clinically, radiographically, and histologically the outcome of RET in immature noninfected human teeth using SynOss Putty (Collagen Matrix Inc, Oakland, NJ) as a scaffold.

Methods: Three pairs of maxillary/mandibular first premolars in 3 patients scheduled for extraction were included. Sensibility tests confirmed the presence of vital pulps. After informed consent, anesthesia, and rubber dam isolation, the pulps were removed. RET was performed using the following scaffolds: SynOss Putty + blood in both teeth in patient #1, SynOss Putty with or without blood in patient #2, and SynOss Putty + blood or blood only in patient #3. After a follow-up period of 2.5-7.5 months, the teeth were clinically and radiographically evaluated, extracted, and examined histologically.

Results: Patients remained asymptomatic after treatment. Radiographic examination of the teeth showed signs of root development after treatment. In teeth treated with SynOss Putty + blood, histologic examination showed formation of intracanal mineralized tissue around the scaffold particles solidifying with newly formed cementumlike tissue on the dentinal walls. The tooth treated with SynOss Putty without blood showed the formation of a periapical lesion. The tooth treated with a blood clot only showed tissues of periodontal origin growing into the root canal space.

Conclusions: SynOss Putty + blood showed a predictable pattern of tissue formation and mineralization when used as a scaffold for RET in human immature noninfected teeth. The newly formed mineralized tissue solidifies with newly formed cementum on the dentinal walls.
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http://dx.doi.org/10.1016/j.joen.2018.10.012DOI Listing
February 2019

Effect of Residual Dental Pulp Tissue on Regeneration of Dentin-pulp Complex: An In Vivo Investigation.

J Endod 2018 Dec;44(12):1796-1801

Private practice, Redlands, California.

Introduction: Current pulp revascularization procedures in teeth with necrotic pulps and open apices have produced histologic evidence of connective tissue growth, cementum, and bone within the root canals of experimental animals. This study aims to investigate the effect of maintaining uninflamed residual apical pulp tissue on the histologic outcome of pulp-dentin complex regeneration after a revascularization procedure in immature ferret cuspid teeth.

Methods: Twenty-eight cuspid teeth from 7 young male ferrets were used in this experiment. Seven teeth were reserved to serve as positive control samples without any treatment. In another 7 teeth, the pulp was completely extirpated (negative control), whereas the pulp of the remaining 14 teeth were removed to either 1-2 mm short of the apex (7 samples) or 2-4 mm short of the apex (7 samples). Blood clots were covered with mineral trioxide aggregate at the cementoenamel junction level of each tooth. Three months later, block sections were removed for histologic evaluations, and the data were statistically analyzed with the chi-square test (P < .05).

Results: All teeth with complete pulp extirpation showed the presence of bone inside the root canal. In contrast, the root canals for most teeth with pulp amputation 1-4 mm from the radiographic apex were filled with normal pulp, which extended coronally to the mineral trioxide aggregate, where hard tissue bridges had formed.

Conclusions: Based on these results, we concluded that regeneration of the pulp-dentin complex is possible when the apical 1-4 mm of the apical pulp remains intact in immature teeth.
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http://dx.doi.org/10.1016/j.joen.2018.09.005DOI Listing
December 2018

Application of Enamel Matrix Derivative (Emdogain) in Endodontic Therapy: A Comprehensive Literature Review.

J Endod 2018 Jul 24;44(7):1066-1079. Epub 2018 Mar 24.

Department of Endodontics, Loma Linda University School of Dentistry, Loma Linda, California.

Introduction: Enamel matrix derivative (EMD) is a protein extract used for the treatment of periodontal defects and soft tissue recession. Its use in endodontics has been a subject of exploration, especially in regenerative procedures. The aim of this review was to evaluate the current literature available on the application of EMD in the field of endodontics.

Methods: An initial literature search of databases using different combinations of the search terms yielded 1089 articles. From the 29 qualified studies, there were 17 animal studies and 12 human case series and clinical trials.

Results: The evidence for the application of EMD as a direct pulp capping agent was relatively dichotomous. In determining the possible effect of EMD on pulpotomy procedures, only 1 animal study qualified under the criteria set forth previously. When comparing EMD against calcium hydroxide (Ca[OH]), Portland cement, and mineral trioxide aggregate (MTA), Ca(OH) induced more histologic hard tissue formation, whereas MTA performed best clinically and radiographically. The scientific literature available is inconclusive on the effectiveness of EMD in preventing root resorption. In regeneration, EMD treatment induced mainly the formation of a cementumlike tissue at the apical region of the root's external surface and showed an ingrowth of newly formed hard tissues into the root canal space.

Conclusions: The results of EMD application in endodontic treatments are highly variable, warranting additional research, specifically in the subjects of replantation and regeneration/revascularization.
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http://dx.doi.org/10.1016/j.joen.2018.02.012DOI Listing
July 2018

Prevalence and Size of Periapical Radiolucencies Using Cone-beam Computed Tomography in Teeth without Apparent Intraoral Radiographic Lesions: A New Periapical Index with a Clinical Recommendation.

J Endod 2018 Mar 1;44(3):389-394. Epub 2018 Feb 1.

Department of Radiology and Imaging Sciences, School of Dentistry, Loma Linda University, Loma Linda, California. Electronic address:

Introduction: The purpose of this study was to determine the prevalence and size of periapical radiolucencies using cone-beam computed tomographic (CBCT) imaging in teeth without apparent signs of intraoral radiographic lesions.

Methods: One hundred twenty roots from 53 patients who had been determined to have no signs of intraoral radiographic lesions were included in this study. Limited-volume CBCT scans were taken at 0.125-mm voxel size. The widest area of apical radiolucency of each root canal-treated tooth was measured and assigned a numeric score based on the CBCT-Endodontic Radiolucency Index (ERI). CBCT data were evaluated by 2 radiologists with an interclass correlation coefficient of 0.96.

Results: The majority of roots (53.3%) had periodontal ligament widths ≤0.5 mm; 26.7% had radiolucency widths of 0.5 < x ≤ 1 mm, 15.0% had radiolucency widths of 1.0 < x ≤ 1.5 mm, 0.8% had radiolucency widths of 1.5 < x ≤ 2.0 mm, 1.7% had radiolucency widths of 2.0 < x ≤ 2.5 mm, and 2.5% had radiolucency widths of >2.5 mm. Patient age, recall interval, tooth type, and arch type had no statistically significant effect on the ERI distribution.

Conclusions: Twenty percent of teeth with successful root canal treatment based on conventional periapical imaging had CBCT radiolucencies measuring greater than 1 mm. Because these radiolucencies may not be pathological changes, clinicians are cautioned against overtreatment of them before determining the true nature of these findings. Clinical studies with long follow-up times are needed to determine the proper course of actions for these cases.
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http://dx.doi.org/10.1016/j.joen.2017.11.015DOI Listing
March 2018

Micro-CT evaluation of voids using two root filling techniques in the placement of MTA in mesial root canals of Vertucci type II configuration.

Clin Oral Investig 2018 Jun 25;22(5):1907-1913. Epub 2017 Nov 25.

Private Practice, Ankara, Turkey.

Objective: The present study aims to compare two mineral trioxide aggregate (MTA) placement techniques, manual compaction and ultrasonic activation of manually compacted MTA, with warm vertical compaction (WVC) for orthograde obturation of mesial root canals of mandibular first molars showing Vertucci type II root canal configuration.

Materials And Methods: Thirty roots were selected according to their micro-CT scanned images. Root canals were chemomechanically prepared using Reciproc R25 and NaOCl using EndoVac. The specimens were divided into three groups according to the root canal filling technique, as manual compaction of MTA, ultrasonic activation of manually compacted MTA and WVC using gutta-percha and AH Plus (Denstply Sirona, Ballaigues, Switzerland). Percentages of voids located in apical 3 mm and remaining coronal half until the level where separate root canals re-join within filling were calculated. Data were analyzed using the Kruskal-Wallis and Dunn's tests, and significance was set at 5%.

Results: No significant difference was found among the filling techniques regarding the percentage volume of voids at apical 3 mm (P > 0.05). At the coronal half of the isthmus, WVC produced significantly less percentage volume of voids than manual compaction of MTA (P < 0.05) and similar to ultrasonic activation group did (P > 0.05). There was no significant difference between two MTA placement techniques at the coronal half of the isthmus (P > 0.05).

Conclusions: No filling technique produced void-free fillings. The percentage of void volume was similar among groups at apical 3 mm but was different at the coronal half of the isthmus.

Clinical Relevance: Warm vertical compaction and ultrasonically activated MTA fillings revealed similar quality at the isthmus area, which was superior to manually compacted MTA.
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http://dx.doi.org/10.1007/s00784-017-2282-0DOI Listing
June 2018

The Influence of Adalimumab on the Healing of Apical Periodontitis in Ferrets.

J Endod 2017 Nov 28;43(11):1841-1846. Epub 2017 Sep 28.

Department of Endodontics, School of Dentistry, Loma Linda University, Loma Linda, California.

Introduction: Given the increasing use of anti-tumor necrosis factor α (anti-TNFα) biologic medications, and their interferences with the immune-inflammatory response, this study evaluated the effect of adalimumab (anti-TNFα), on healing and healing time of apical periodontitis (AP) in ferrets.

Methods: Twelve male ferrets received cone beam computed tomography of the jaws at baseline health (T0); AP confirmation (T1); and 30 (T2), 60 (T3), and 90 (T4) days after root canal treatment (RCT) to monitor healing. All animals had AP induced in the canines; 3 ferrets (12 teeth) provided the positive controls for the histologic evaluation; 9 ferrets were randomly divided into 3 treatment groups with 12 teeth each in the following manner: Systemic: conventional RCT and systemic anti-TNFα; Local: RCT and periapical administration of anti-TNFα before canal obturation; conventional RCT only (control). Two calibrated radiologists assessed the cone beam computed tomography images independently and blindly for AP identification and quantification. Rank-based analysis of covariance was used for statistical analysis of lesion size.

Results: AP was induced in all teeth. Following RCT, all AP lesions in the 3 groups showed a significant reduction in size. Specific pairwise comparisons of the related samples (Friedman's 2-way analysis of variance by ranks within each group) demonstrated a decreasing trend in lesion size with healing time in all 3 groups, most pronounced for local group (local adalimumab). No statistical difference was noticed between groups.

Conclusions: Both systemic and local anti-TNFα did not hinder AP healing in this animal model and a faster healing response may also be anticipated. These findings encourage follow-up studies with larger sample sizes.
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http://dx.doi.org/10.1016/j.joen.2017.06.019DOI Listing
November 2017

The haemostatic efficacy and foreign body reaction of epinephrine-Impregnated polyurethane foam in osseous defects.

Aust Endod J 2018 Dec 21;44(3):204-207. Epub 2017 Sep 21.

Endodontics, Loma Linda University, Loma Linda, California, USA.

The objective of this study was to compare the haemostatic efficacy and foreign body reaction of epinephrine-impregnated cotton pellets with those of epinephrine-impregnated polyurethane (PU) foam cubes in osseous defects created in guinea pigs. Initially, these substances were randomly applied to the osseous defects in guinea pigs for 2 min and blood loss was measured. The animals were then sacrificed 7 weeks later and the degree of foreign body reaction was scored. The data were analysed by the independent-samples Kruskal-Wallis test. Epinephrine-impregnated PU foam cubes showed significantly better haemostatic effect compared to epinephrine-impregnated cotton pellets. The PU foam containing epinephrine specimens elicited significantly less foreign body reaction compared to epinephrine cotton pellets (P < 0.05). Based on the results of this study, it is concluded that epinephrine-impregnated PU foam cubes are a good alternative to epinephrine-impregnated cotton pellets as a local haemostatic agent in endodontic surgery.
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http://dx.doi.org/10.1111/aej.12234DOI Listing
December 2018

Regenerative Endodontic Treatment or Mineral Trioxide Aggregate Apical Plug in Teeth with Necrotic Pulps and Open Apices: A Systematic Review and Meta-analysis.

J Endod 2017 Nov 16;43(11):1806-1820. Epub 2017 Aug 16.

Department of Dental Education, School of Dentistry, Loma Linda University, Loma Linda, California.

Introduction: A mineral trioxide aggregate (MTA) apical plug (MAP) and regenerative endodontic treatment (RET) have shown acceptable clinical outcomes. However, comparative studies are scarce. The aims of this study were to examine the level of evidence for both treatments, conduct a systematic review of the literature on MAP and RET, and run a meta-analysis on the survival and success rates of teeth treated with these procedures.

Methods: Electronic searches were performed in MEDLINE, Web of Science, and the Cochrane Library. Two authors independently screened the titles and abstracts for eligibility. Subgroup analyses were performed on the clinical outcomes (ie, survival and success) of the procedures.

Results: In all, 750 studies were identified, and 144 studies were subjected to qualitative synthesis. Ten randomized clinical trials were included in subgroup analyses. Most of the studies in both groups were case reports and case series (72% and 86% in MAP and RET, respectively). The overall level of evidence in both groups was low. The pooled survival rates were 97.1% (95% confidence interval [CI], 93.7-100) and 97.8% (95% CI, 94.8-100) for MAP and RET, respectively. The pooled success rates were 94.6% (95% CI, 90.2-99.1) and 91.3% (95% CI, 84.5-98.2) for MAP and RET, respectively. Very little heterogeneity was observed among the studies regarding survival and success rates (I < 50%, P > .10). There was no significant difference between the 2 groups regarding survival (P = 1.00) or success rates (P = .58).

Conclusions: The existing literature lacks high-quality studies with a direct comparison of outcomes of MAP and RET. Randomized multicenter clinical trials with large sample sizes and long-term follow-ups are needed to address this gap in knowledge.
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http://dx.doi.org/10.1016/j.joen.2017.06.029DOI Listing
November 2017

Prevalence of Second Mesiobuccal Canals in Maxillary First Molars Detected Using Cone-beam Computed Tomography, Direct Occlusal Access, and Coronal Plane Grinding.

J Endod 2017 Oct 20;43(10):1711-1715. Epub 2017 Jul 20.

Department of Endodontics, Loma Linda University School of Dentistry, Loma Linda, California.

Introduction: The purpose of this study was to determine the prevalence of the second mesiobuccal canal (MB2) in 100 maxillary first molars using 3 independent methods and a combination method.

Methods: One hundred extracted human maxillary first molars were collected. The teeth were mounted in the maxillary first molar extraction sockets of a human cadaver head. A cone-beam computed tomographic (CBCT) scan was taken of each tooth. Two radiology faculty independently evaluated the CBCT volume for the presence of an MB2 canal. Additionally, teeth were accessed. If a canal was not found, a preoperative CBCT scan was viewed followed by a second attempt to locate an MB2 canal. Lastly, the mesiobuccal root was dissected by grinding in a coronal plane.

Results: A review of CBCT volumes found the presence of an MB2 canal 69% of the time. Accessing the tooth led to an MB2 detection of 78%. When a CBCT scan was viewed, this brought the access detection rate up to 87%. Coronal plane root grinding had an MB2 canal detection rate of 92%. Differences between each method were statistically significant.

Conclusions: The results of this study show that an MB2 canal is present up to 92% of the time. Direct access of teeth found statistically significant more MB2 canals than viewing CBCT volumes alone (P = .032). Therefore, exposing every patient to a preoperative CBCT scan may not be appropriate. However, taking a CBCT scan when an MB2 canal is not found clinically can significantly increase the chances of finding an MB2 canal (P < .001).
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http://dx.doi.org/10.1016/j.joen.2017.05.011DOI Listing
October 2017

Cytotoxicity and Antimicrobial Effects of a New Fast-Set MTA.

Biomed Res Int 2017 20;2017:2071247. Epub 2017 Feb 20.

Department of Endodontics, School of Dentistry, Loma Linda University, Loma Linda, CA 92350, USA.

. To compare the biocompatibility and antimicrobial effectiveness of the new Fast-Set MTA (FS-MTA) with ProRoot MTA (RS-MTA). . The agar overlay method with neutral red dye was used. L929 mouse fibroblast cells were cultured. The liquid and oil extracts and solid test material were placed on the agar overlay, four samples for each material. Phenol was used as the positive control and cottonseed oil and MEM extracts were used as negative controls. Cytotoxicity was examined by measuring the zones of decolorization and evaluating cell lysis under an inverted microscope using the established criteria after 24 and 48 hours. The antimicrobial test was performed using the Kirby-Bauer disk-diffusion method against , , , , and . The size of the zone of inhibition was measured in millimeters. There was no zone of decolorization seen under or around the test materials for FS-MTA and RS-MTA at 24 and 48 hours. The antimicrobial test demonstrated no inhibitory effect of FS-MTA or RS-MTA on any bacterial species after 24 and 48 hours. There was no cytotoxicity or bacterial inhibition observed by the new Fast-Set MTA when compared to the ProRoot MTA after setting.
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http://dx.doi.org/10.1155/2017/2071247DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5337838PMC
March 2017

Effect of apex size on the leakage of gutta-percha and sealer-filled root canals.

Quintessence Int 2016 ;47(5):373-8

Objectives: There are no data comparing coronal leakage of teeth prepared to different apical sizes and obturated with gutta-percha and sealer. The aim of this study was to investigate the effect of apical preparation size on the leakage of obturated root canals. Large apical openings are encountered as a result of pulp necrosis in immature teeth, apical resorption, or over-enlargement of the apical foramen. Complete cleaning, shaping, obturation, and apical seal of root canal systems are essential for the success of root canal treatment.

Method And Materials: One hundred twenty-five extracted human teeth were divided into groups containing 25 samples each and prepared to apical file sizes 30, 40, 50, 60, and 70. Twenty teeth served as positive and negative controls. Obturation was completed with gutta-percha and sealer via warm vertical compaction. Bacterial leakage was investigated after 112 days using Proteus vulgaris. Data were analyzed via independent-samples Kruskal-Wallis test.

Results: The average time for leakage of apical preparation sizes 30, 40, 50, 60, and 70 were 57.5, 52.4, 47.2, 37.5, and 28.4 days, respectively. Significant differences in leakage were observed between apical preparation sizes 70 versus 30, 70 versus 40, 70 versus 50, as well as 60 versus 30. A trend for more leakage occurred when apical preparation sizes exceeded size 60.

Conclusions: Based on these results, it appears leakage of gutta-percha and sealer as obturation materials increases when apical preparation size exceeds 60. Consideration should be given to using sealing materials other than gutta-percha and sealer when the apex size exceeds 60.
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http://dx.doi.org/10.3290/j.qi.a35525DOI Listing
August 2017

Endodontic treatment options after unsuccessful initial root canal treatment: Alternatives to single-tooth implants.

J Am Dent Assoc 2016 Mar 9;147(3):214-20. Epub 2016 Jan 9.

Background And Overview: Initial root canal treatment is highly successful, appreciated by patients, and cost-effective, but failures occur. Should a tooth with unsuccessful initial root canal treatment be treated by means of other endodontic procedures or be replaced by a single-tooth implant?

Results: Results from systematic reviews of the outcomes of nonsurgical retreatment, apical surgery, replantation, and autotransplantation show high tooth survival rates. Nonsurgical retreatment generally is prioritized before surgical endodontic treatment. Microsurgical endodontic treatment is superior to traditional surgical endodontic treatment and has high survival rates. Intentional replantation remains a viable alternative to extraction. Autotransplantation has a place, particularly in growing patients with an appropriate donor tooth. Single-tooth implants have higher survival rates, but the natural state has intrinsic value.

Conclusions: The first-line treatment option after failure of initial root canal treatment is nonsurgical retreatment. Endodontic surgery, intentional replantation, and autotransplantation should be considered before extraction and replacement by a single-tooth implant.

Practical Implications: Comprehensive case assessment, evaluation of all endodontic options, and risk assessment for caries and periodontal disease are always necessary when choosing the optimal treatment for a patient when initial root canal treatment has failed to heal.
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http://dx.doi.org/10.1016/j.adaj.2015.11.017DOI Listing
March 2016

Histologic Outcomes of Uninfected Human Immature Teeth Treated with Regenerative Endodontics: 2 Case Reports.

J Endod 2015 Oct 7;41(10):1725-9. Epub 2015 Aug 7.

Advanced Specialty Education Program in Endodontics, School of Dentistry, Loma Linda University, Loma Linda, California. Electronic address:

A growing body of evidence exists showing the possibility of growing vital tissues in the root canal spaces of teeth with necrotic pulps and open apices. However, there is very limited histologic information regarding characteristics of tissues formed in the root canal space of human teeth after regenerative endodontics. The aim of this study was to examine clinically and histologically the outcomes of human immature teeth treated with regenerative endodontics. Two healthy birooted human maxillary first premolar teeth scheduled for extraction were included. Preoperative radiographs confirmed that these teeth had immature apices. Vitality tests showed the presence of vital pulps in these teeth. After receiving consent forms, the teeth were isolated with a rubber dam, and the pulps were completely removed. After the formation of blood clots in the canals, the teeth were covered with mineral trioxide aggregate. Four months later, the teeth were clinically and radiographically evaluated, extracted, and examined histologically. Both patients remained asymptomatic after treatment. Radiographic examination of the teeth showed signs of root development after treatment. Histologic examination of tissues growing into the root canal space of these teeth shows the presence of connective tissue, bone and cementum formation, and thickening of roots. Based on our findings, it appears that when canals of teeth with open apices are treated with regenerative endodontics, tissues of the periodontium grow into the root canals of these teeth.
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http://dx.doi.org/10.1016/j.joen.2015.05.004DOI Listing
October 2015

Effect of three calcium hydroxide formulations on fracture resistance of dentin over time.

Dent Traumatol 2015 Oct 19;31(5):380-4. Epub 2015 Apr 19.

Department of Endodontics, Loma Linda School of Dentistry, Loma Linda, CA, USA.

Background: The long-term use of calcium hydroxide has been discouraged throughout the recent decade due to a proposed decrease in fracture resistance of dentin. This weakening has grave implications when used on immature teeth with thin dentinal walls in procedures such as apexogenesis.

Aim: The purpose of this study was to identify the effects of three commercial calcium hydroxide formulations (Vitapex, Ultracal XS and Pulpdent) on the fracture resistance of dentin in relation to time.

Materials And Methods: Two-hundred and forty deciduous lamb incisors were collected, cleaned and shaped, and filled with one of the three calcium hydroxide formulations and one negative saline control. At one, three, and 6 months, these teeth were fractured on an Instron machine to determine fracture resistance.

Results: No statistical differences were observed among any of the experimental groups, nor between any of the experimental groups and negative control groups.

Conclusions: Based on our findings, there appears insufficient evidence to support that either Vitapex, Ultracal XS, or Pulpdent will cause a decrease in fracture resistance of dentin within a 6-month period.
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http://dx.doi.org/10.1111/edt.12175DOI Listing
October 2015

Dye leakage and modification of fast-setting mineral trioxide aggregate.

J Calif Dent Assoc 2015 Feb;43(2):82-6

The objective of this investigation was to determine and decrease dye leakage of fast-setting mineral trioxide aggregate (FSMTA). Specimens using differing setting times or concentrations of calcium sulfate modified FSMTA were assessed for dye penetration. Based on the results, no statistical difference was found in the dye leakage of FSMTA compared with regular mineral trioxide aggregate (MTA). The addition of 10 percent calcium sulfate resulted in a statistical reduction in dye leakage compared to both unmodified FSMTA and regular MTA.
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February 2015

Histologic examination of teeth with necrotic pulps and periapical lesions treated with 2 scaffolds: an animal investigation.

J Endod 2015 Jun 6;41(6):846-52. Epub 2015 Mar 6.

Loma Linda University School of Dentistry, Loma Linda, California.

Introduction: Traditional pulp regeneration procedures that use a blood clot as a scaffold have produced histologic evidence of bone, cementum, and connective tissue growth within the root. Platelet-rich plasma (PRP) is a bioactive scaffold containing growth factors that enhance wound healing.

Aim: The aim of this study was to histologically compare the tissues generated when PRP or a blood clot is placed into teeth with preexisting necrotic pulps and periapical lesions.

Methods: Twenty-four canine teeth from 6 immature ferrets were used. Two ferrets served as positive controls. Sixteen experimental canine teeth from 4 ferrets were infected, debrided, treated with a triple antibiotic paste, and randomly distributed to the following groups: group 1 (blood clot/Gelfoam), group 2 (PRP), and group 3 (no scaffold). At 3 months, the ferrets were sacrificed, and the tissues were evaluated histologically. Data were analyzed by using the Fisher exact test (P < .05).

Results: In 3 of 6 teeth in the PRP group, 2 of 6 teeth in the blood clot group, and 1 of 4 teeth in the no scaffold group, an ingrowth of hard tissues was observed in the apical third of the roots. When using PRP or a blood clot as a scaffold, we found significantly more apical narrowing and hard tissue deposition in comparison to not using a scaffold (P < .05).

Conclusions: The use of PRP or blood clots as scaffolds results in the ingrowth of bone-like, cementum-like, and connective tissue in the apical third of the roots at inconsistent rates.
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http://dx.doi.org/10.1016/j.joen.2015.01.026DOI Listing
June 2015

Survival of Intentionally Replanted Teeth and Implant-supported Single Crowns: A Systematic Review.

J Endod 2015 Jul 3;41(7):992-8. Epub 2015 Mar 3.

UCLA School of Dentistry, Los Angeles, California.

Introduction: Although nonsurgical initial root canal treatment and retreatment have high success rates, periapical disease can remain. The survival rates of 2 surgical procedures, intentionally replanted (IR) teeth and implant-supported single crowns (ISCs), have yet to be compared. The purpose of this systematic review and meta-analysis was to examine the literature and quantify the survival of IR teeth and compare it with that of ISCs.

Methods: Systematic searches were enriched by citation mining. Weighted survival means and 95% confidence intervals (CI) were estimated using a random-effects model and compared.

Results: The quality of the IR and ISC articles was only moderate. Data for ISCs were much more plentiful than for IR teeth. Meta-analysis revealed a weighted mean survival of 88% (95% CI, 81%-94%) for IR teeth. Root resorption was reported with a mean prevalence of 11%. The weighted mean survival of ISCs was 97% (95% CI, 96%-98%). The mean survival of ISCs was significantly higher than that of IR teeth (P < .001). A recent study on IR teeth indicated that orthodontic extrusion before intentional replantation improved survival rates.

Conclusions: A systematic review and meta-analysis found that the mean survival of ISCs was significantly higher than IR teeth. However, treatment decisions must be based on a wide variety of treatment and patient-specific parameters. Intentional replantation may have a role when ISC is not practicable. Studies using contemporary treatment and analytic methods should be used to identify and measure intentional replant prognostic and treatment variables.
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http://dx.doi.org/10.1016/j.joen.2015.01.004DOI Listing
July 2015

Tooth retention through endodontic microsurgery or tooth replacement using single implants: a systematic review of treatment outcomes.

J Endod 2015 Jan 11;41(1):1-10. Epub 2014 Oct 11.

UCLA School of Dentistry, Los Angeles, California.

Introduction: Clinicians are regularly confronted with difficult choices. Should a tooth that has not healed through nonsurgical root canal treatment be treated through endodontic microsurgery or be replaced using a single implant? Acquiring complete, unbiased information to help clinicians and their patients make these choices requires a systematic review of the literature on treatment outcomes. The purpose of this systematic review was to compare the outcomes of tooth retention through endodontic microsurgery to tooth replacement using an implant supported single crown.

Methods: Searches performed in PubMed, Cochrane Library, Web of Science, and EMBASE databases were enriched by citation mining. Inclusion criteria were defined. Sentinel articles were identified and included in the final selection of studies. Weighted survival and success rates for single implants and endodontic microsurgery were calculated.

Results: The quality of the articles reporting on single implants and endodontic microsurgery was moderate. Data for single implants were much more plentiful than for endodontic microsurgery, but the endodontic microsurgery studies had a slightly higher quality rating. Single implants and endodontic microsurgery were not directly compared in the literature. Outcomes criteria were often unclear. At 4-6 years, single implants had higher survival rates than teeth treated with endodontic microsurgery. Qualitatively different success criteria precluded valid comparison of success rates.

Conclusions: Survival rates for single implants and endodontic microsurgery were both high (higher for single implants). Appraisal was limited by a lack of direct treatment comparisons. Long-term studies with a broad range of carefully defined outcomes criteria are needed.
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http://dx.doi.org/10.1016/j.joen.2014.09.002DOI Listing
January 2015

Degree of patient pain, complications, and satisfaction after root canal treatment or a single implant: a preliminary prospective investigation.

J Endod 2014 Dec 8;40(12):1940-5. Epub 2014 Oct 8.

Departments of Endodontics and Implant Dentistry, School of Dentistry, Loma Linda University, Loma Linda, California.

Introduction: Dentists often face the choice between tooth retention with root canal treatment and tooth replacement with implant treatment. To date, there has not been a prospective clinical trial directly comparing nonsurgical root canal treatment and single delayed implant therapy with regard to the degree of preoperative and postoperative pain, complications, and patient satisfaction.

Methods: Twenty-four patients had initial nonsurgical root canal treatment, and another 24 had single implant treatment in healed sites. Questionnaires were given at pretreatment, 7 days, 3 months, 6 months, and 12 months.

Results: All patients completed the 12-month follow-up period. No significant difference in pain, complications, or overall satisfaction was noted between the 2 groups at any of the time points (P > .05). However, there were differences within each group between the time points. There was more pain at pretreatment for root canal treatment and 7-day post-treatment point for single implant treatment than any other time point. For complications, more were reported at the 7-day post-treatment point than any other time point for both groups. With overall satisfaction, there was no difference from any time point for either group.

Conclusions: The results of this study suggest that patients perceive both treatments with high degrees of satisfaction with minimal pain and discomfort. Differences were found at different time points of treatment and were related to the nature of the treatment itself. This information is useful to help patients with treatment decisions.
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http://dx.doi.org/10.1016/j.joen.2014.08.022DOI Listing
December 2014

Histologic examinations of teeth treated with 2 scaffolds: a pilot animal investigation.

J Endod 2014 Apr 12;40(4):515-20. Epub 2014 Feb 12.

Loma Linda University, Loma Linda, California.

Introduction: A growing body of evidence is building a case for the possibility of tissue regeneration within the root canal of necrotic teeth, allowing for continued root development. However, it remains unknown what type of tissue is produced after regenerative endodontics. The purpose of this study was to use blood clots and platelet-rich plasma (PRP) as scaffolds in regenerative endodontics under ideal conditions in a ferret model to examine the tissues generated within the root canals.

Methods: The pulps of 21 canine teeth from 7 young ferrets were extirpated using broaches without filing the canal walls. Bleeding was stimulated from the periapical tissues, and a blood clot was induced in the canal space to the level of the cementoenamel junction in 12 teeth. PRP was prepared and placed in the canals to the level of the cementoenamel junction in 9 teeth. The coronal access was sealed with mineral trioxide aggregate. Seven canines were not operated on and served as controls. Three months later, block sections including each canine and its surrounding tissues were removed for histologic evaluation. The tissues found in the canals of experimental teeth were compared with those in the control teeth.

Results: Almost all of the experimental teeth showed the presence of intracanal bonelike tissue. No evidence of dentinal wall thickening or apical narrowing was noted in the experimental teeth.

Conclusions: In this experimental model, the use of either PRP or blood clots during regenerative endodontics leads to the formation of intracanal bonelike tissue without continual root maturation.
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http://dx.doi.org/10.1016/j.joen.2013.12.025DOI Listing
April 2014

Comparison of efficacy of pulverization and sterile paper point techniques for sampling root canals.

J Endod 2013 Aug 21;39(8):1057-9. Epub 2013 May 21.

Departments of Endodontics and Pediatric Dentristy, School of Dentistry, Loma Linda, CA 92350, USA.

Introduction: The purpose of this study was to compare the efficacy of the pulverization and sterile paper point techniques for sampling root canals using 5.25% NaOCl/17% EDTA and 1.3% NaOCl/MTAD (Dentsply, Tulsa, OK) as irrigation regimens.

Methods: Single-canal extracted human teeth were decoronated and infected with Enterococcus faecalis. Roots were randomly assigned to 2 irrigation regimens: group A with 5.25% NaOCl/17% EDTA (n = 30) and group B with 1.3% NaOCl/MTAD (n = 30). After chemomechanical debridement, bacterial samplings were taken using sterile paper points and pulverized powder of the apical 5 mm root ends.

Results: The sterile paper point technique did not show growth in any samples. The pulverization technique showed growth in 24 of the 60 samples. The Fisher exact test showed significant differences between sampling techniques (P < .001). The sterile paper point technique showed no difference between irrigation regimens. However, 17 of the 30 roots in group A and 7 of the 30 roots in group B resulted in growth as detected by pulverization technique. Data showed a significant difference between irrigation regimens (P = .03) in pulverization technique.

Conclusions: The pulverization technique was more efficacious in detecting viable bacteria. Furthermore, this technique showed that 1.3% NaOCl/MTAD regimen was more effective in disinfecting root canals.
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http://dx.doi.org/10.1016/j.joen.2013.04.012DOI Listing
August 2013

The effect of sonophoresis on topical anesthesia: a pilot project.

Anesth Prog 2013 ;60(2):37-41

Loma Linda University School of Dentistry, Loma Linda, California, USA.

The dental anesthesia sonophoresis device (DASD) is a novel device that is intended to reduce the discomfort associated with intraoral mucosa needle puncture. The DASD produces ultrasonic energy that provides a sonophoretic effect on the oral mucosa, generating microchannels through the lipids between the keratinized cells that make up the stratum corneum. Once the topical anesthetic has permeated the stratum corneum, it quickly diffuses through the soft tissue, desensitizing the nerve endings and reducing the perception of pain caused by needle penetration. The aim of this study is to evaluate whether topical anesthesia applied using the DASD will reduce the discomfort of the needle puncture when compared to the control device. A split-mouth model, using 50 healthy subjects with puncture site at the maxillary canine vestibule, was used for this study. Subjects received a needle puncture on both sides of the mouth. Prior to the needle puncture, there was randomized application of 5% lidocaine with the DASD and a control device. Subjects rated their discomfort after needle punctures utilizing the visual analog scale pain scoring system. There was no statistically significant difference in the pain perception using the DASD versus the control device.
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http://dx.doi.org/10.2344/0003-3006-60.2.37DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3683878PMC
August 2013

Accuracy of cone-beam computed tomography and periapical radiography in detecting small periapical lesions.

J Endod 2012 Jul 18;38(7):965-70. Epub 2012 May 18.

School of Dentistry, Loma Linda University, Loma Linda, CA 92350, USA.

Introduction: The aim of this study was to determine the diagnostic accuracy of 2 cone-beam computed tomography (CBCT) machines and periapical (PA) radiography in detecting simulated apical lesions created with the smallest dental burs available.

Methods: By using mandibles from human cadavers, simulated apical lesions were created and then progressively enlarged in 16 roots by using sizes #1/4, #1/2, #1, #2, #4, and #6 round burs. Imaging was obtained after each enlargement with a Kodak 9000 3D (Kodak) CBCT, a Veraviewpocs 3De (Morita) CBCT, and intraoral digital PA radiography. Specificity and sensitivity at variable decision thresholds were calculated and plotted on receiver operator characteristic curves. The area under the curve (AUC) served as an estimate of diagnostic accuracy.

Results: The overall AUCs for Kodak, Morita, and PA radiography were 0.767 (95% confidence interval [CI], 0.743-0.792), 0.753 (95% CI, 0.728-0.779), and 0.584 (95% CI, 0.554-0.615), respectively. The AUCs for Kodak and Morita were both statistically significantly larger than the AUC for all corresponding simulated lesion sizes imaged with PA radiography. Between Kodak and Morita, there were no statistically significant differences in AUCs for any of the corresponding simulated lesion sizes.

Conclusions: Both CBCT devices demonstrated poor accuracy in detecting simulated lesions smaller than 0.8 mm in diameter, fair to good accuracy when simulated lesion diameter was between 0.8-1.4 mm, and excellent accuracy when simulated lesions were larger than 1.4 mm in diameter. PA radiography, at best, demonstrated poor diagnostic accuracy for all simulated lesion sizes.
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http://dx.doi.org/10.1016/j.joen.2012.03.001DOI Listing
July 2012

A clinical and histological report of a tooth with an open apex treated with regenerative endodontics using platelet-rich plasma.

J Endod 2012 Jun;38(6):864-8

Department of Endodontics, School of Dentistry, Londa Linda University, Loma Linda, California 92350, USA.

Introduction: In patients, the outcomes of teeth with necrotic pulps and open apexes that have been treated with regenerative endodontics have always been evaluated clinically and radiographically. The purpose of this case report is to present the clinical, radiographic, and histological findings of a regenerative procedure using platelet-rich plasma (PRP) 14 months after the procedure.

Methods: A 12-year-old boy whose maxillary second premolar tooth had been treated with regenerative endodontics was seen with a chief complaint of pain and sensitivity to cold. After clinical and radiographic examinations, a pulpal diagnosis of reversible pulpitis and normal periapical tissues was made for this tooth. Because of the patient's complaint and his guardian's insistence on either a root canal treatment or an extraction, a root canal treatment was performed in this tooth. After entry into the root canal, the soft tissue present in the canal was removed with the aid of a large barbed broach and examined histologically.

Results: Examination of the tissue removed from the root canal of this tooth revealed the presence of a vital pulp-like vital connective tissue. There was no evidence of bone in the specimen. Very few inflammatory cells were noted in the periphery of the specimen.

Conclusions: Based on these findings, it appears that pulp-like tissue can be generated in a human tooth with the use of PRP as a scaffold in regenerative endodontic procedures.
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http://dx.doi.org/10.1016/j.joen.2012.03.006DOI Listing
June 2012
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