Publications by authors named "Brian E Bergeron"

28 Publications

  • Page 1 of 1

Effects of pre-mixed hydraulic calcium silicate putties on osteogenic differentiation of human dental pulp stem cells in vitro.

J Dent 2021 05 30;108:103653. Epub 2021 Mar 30.

Department of Endodontics, The Dental College of Georgia, Augusta University, Augusta, GA, USA. Electronic address:

Objectives: An experimental tricalcium silicate and dicalcium silicate-containing endodontic putty has been designed to overcome the issue of reduced shelf life after exposure to atmospheric moisture during repeated opening of the container for clinical retrieval. The present study examined the effects of this experimental hydraulic putty on the mineralogenic characteristics of osteogenic lineage-committed human dental pulp stem cells (hDPSCs), by comparing the cellular responses with a commercially available putty (EndoSequence BC RRM Putty).

Methods: The osteogenic potential of hDPSCs that had been exposed to the putties was examined using quantitative reverse-transcription polymerase chain reaction for osteogenic gene expressions and western blot for osteogenic protein expressions. Alkaline phosphatase activity assay and alizarin red S staining were performed to detect changes in production of the intracellular enzyme and extracellular matrix mineralization respectively.

Results: Osteogenic differentiation of the hDPSCs was significantly enhanced after exposure to the pre-mixed hydraulic putties, with no significant difference between these two examined putties.

Conclusions: The experimental hydraulic tricalcium silicate putty enhances osteogenic differentiation of hDPSCs to the same extent as a commercially available tricalcium silicate putty.

Clinical Significance: The experimental hydraulic putty appears to be an alternative to the commercial putty when used for applications involving the regeneration of bone in endodontics. Animal models are required for validating its potential in enhancing osteogenesis in vivo.
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http://dx.doi.org/10.1016/j.jdent.2021.103653DOI Listing
May 2021

Manoeuvrability and biocompatibility of endodontic tricalcium silicate-based putties.

J Dent 2021 01 19;104:103530. Epub 2020 Nov 19.

Department of Endodontics, The Dental College of Georgia, Augusta University, Augusta, GA, USA. Electronic address:

Objectives: The present study evaluated the indentation depth, storage modulus and biocompatibility of an experimental endodontic putty designed for endodontic perforation repair and direct pulp-capping (NeoPutty). The results were compared with the properties associated with the commercially available EndoSequence BC RRM Putty (ES Putty).

Methods: Indentation depth was measured by a profilometer following indentation with the 1/4 lb Gilmore needle. Elastic modulus was evaluated using a strain-controlled rheometer. The effects of eluents derived from these two putties were examined on the viability and proliferation of human dental pulp stem cells (hDPSCs) and human periodontal ligament fibroblasts (hPDLFs), before (1 st testing cycle) and after complete setting (2nd testing cycle).

Results: The ES Putty became more difficult to ident and acquired a larger storage modulus after exposure to atmospheric moisture. Biocompatibility results indicated that both putties were relatively more cytotoxic than the bioinert Teflon negative control, but much less cytotoxic than the zinc oxide-eugenol cement negative control. NeoPutty was less cytotoxic than ES putty in the 1st testing cycle, particularly with hDPSCs. Both putties exhibited more favourable cytotoxicity profiles after complete setting.

Conclusions: NeoPutty has a better window of maneuverability after exposure to atmospheric moisture. From an in vitro cytotoxicity perspective, the NeoPutty may be considered more biocompatible than ES putty.

Clinical Significance: The experimental NeoPutty is biocompatible and is capable of reducing the frustration of shortened shelf life when jar-stored endodontic putties are exposed to atmospheric moisture during repeated opening of the lid for clinical retrieval.
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http://dx.doi.org/10.1016/j.jdent.2020.103530DOI Listing
January 2021

Micro-computed tomography evaluation of root canal filling quality with apical negative pressure.

J Dent 2020 09 16;100:103431. Epub 2020 Jul 16.

The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China. Electronic address:

Objectives: The objective of the present study was to compare, using micro-computed tomography (micro-CT), the location and volume percentage of voids in root canals that were obturated with a premixed tricalcium silicate sealer and a single gutta-percha master cone, in the presence or absence of apical negative pressure.

Methods: Twenty extracted human mandibular premolars were cleaned and shaped. The teeth were assigned to 2 groups (n = 10) according to the filling technique: apical negative pressure sealer application combined with the single-cone technique (NPS) or syringe-assisted sealer application combined with the single-cone technique (SS). Each specimen was scanned using micro-CT at 10 μm resolution. The percentages of voids were calculated from segmental regions of interest. Data were analysed using nonparametric statistical methods, with statistical significance pre-set at α = 0.05.

Results: Significant difference was identified (p < 0.05) in the overall percentage of voids between the NPS group (0.33 %; interquartile range 0.25 %) and the SS group (6.29 %; interquartile range 5.57 %). In the NPS group, the percentages of voids in the coronal-third or middle-third of the canal space were statistically lower than that in apical-third (p < 0.0167, Bonferroni adjustment), with no significant difference between the former two groups. In the SS group, no significant difference in the percentages of voids was identified among the coronal-third, middle-third and apical-third of the canal space.

Conclusions: Apical negative pressure sealer application combined with the single-cone technique produces fewer voids in root canal fillings than the conventional single-cone technique.

Clinical Significance: The apical negative pressure sealer application technique combined with single-cone filling constitutes a novel root canal obturation technique that improves the quality of root canal filling by minimising the volume of voids within the three-dimensional canal space.
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http://dx.doi.org/10.1016/j.jdent.2020.103431DOI Listing
September 2020

Effects of calcium-phosphate, laser and adhesive on dentin permeability and bond strength.

Heliyon 2020 May 11;6(5):e03925. Epub 2020 May 11.

Department of Restorative Dentistry, Institute of Science and Technology, São Paulo State University-UNESP, São Jose dos Campos, SP, Brazil.

Objectives: The present study examined a technique for reducing dentin permeability through the application of a calcium phosphate (CaP)-based desensitiser with a laser-assisted process and evaluated adhesive-dentin bond strength. : Thirty dentin discs were divided into two groups according to whether the selected desensitiser (TeethMate; Kuraray Noritake) was used prior to dentin bonding. Each group was subdivided into three subgroups (n = 5): A- Adhesive (Single Bond Universal, 3M ESPE), AL- Adhesive + Laser (Nd:YAG 60 mJ) and LAL- Laser + Adhesive + Laser. Dentin permeability values (%) were recorded before and after desensitiser application. Resin composites were placed over the bonded specimens; the latter were aged prior to microtensile bond strength evaluation. Gelatinolytic activity within the hybrid layers was examined with zymography using confocal laser scanning microscopy. Data were analysed with ANOVA and Tukey test (α = 0.05).

Results: Significant differences in dentin permeability were identified for all groups (p = 0.00). Both laser treatment (p = 0.182) and desensitiser application (p = 0.687) did not significantly improve dentin bond strength. Ultrastructure of the resin-dentin interface identified presence of calcium phosphate within dentinal tubules. Laser treatment did not affect hybrid layer ultrastructure. Both treatment modalities (intratubular CaP occlusion and laser) had no influence on gelatinolytic activity within hybrid layers.

Conclusion: Although intratubular CaP occlusion and laser treatment were effective in reducing dentin permeability, they did not affect bond strength, interfacial ultrastructure and gelatinolytic activity within hybrid layers.

Clinical Relevance: Treatment of etched dentin with Nd:YAG Laser at 60 mJ does not adversely affect collagen ultrastructure and gelatinolytic activity within the hybrid layer. The application of a calcium phosphate-based desensitiser to etch dentin does not affect dentin bond strength.
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http://dx.doi.org/10.1016/j.heliyon.2020.e03925DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7218263PMC
May 2020

Comparison of the use of d-enantiomeric and l-enantiomeric antimicrobial peptides incorporated in a calcium-chelating irrigant against Enterococcus faecalis root canal wall biofilms.

J Dent 2019 12 8;91:103231. Epub 2019 Nov 8.

The Dental College of Georgia, Augusta University, Augusta, GA, USA. Electronic address:

Objectives: To compare the anti-biofilm efficacy of two antimicrobial peptides (AMPs), 1018 and DJK-5, in disrupting canal wall biofilms in the isthmus, canal and dentinal tubules of single-rooted maxillary premolars.

Methods: Enterococcus faecalis single-species biofilms were formed in-situ in the root canal system of the premolars (n = 91). Confocal laser scanning microscopy, bacterial sampling, colony-forming unit counting, XTT assay, lactate dehydrogenase assay and phenol-sulphuric acid method were used to identify the anti-biofilm efficacy of both AMPs and their influence on bacterial metabolic activity.

Results: Both AMPs disrupted in-situ E. faecalis biofilms and altered their metabolic activity. At 20 μg/mL, the d-enantiomeric AMP DJK-5 killed 55.5 %, 57.3 % and 55.8 % of biofilm bacteria in the isthmus, canal and dentinal tubules, respectively, in 1 min. In contrast, the l-enantiomeric AMP 1018 only eradicated 25.6 %, 25.5 % and 27.5 % of biofilm bacteria in the isthmus, canal and dentinal tubules, respectively, within the same time. Anti-biofilm efficacy of the root canal irrigants tested were in the order: 6 % NaOCl > 20 μg/mL DJK-5 > 10 μg/mL DJK-5 > 20 μg/mL 1018 > 10 μg/mL 1018 > 0.9 % NaCl.

Conclusions: The present results are confirmatory of previous studies, in that d-enantiomeric AMPs exhibit more potent antibacterial properties than l-enantiomeric AMPs against E. faecalis biofilms within the canal space. Nevertheless, the potency of both AMPs are concentration-dependent. Incorporation of these agents into EDTA, a non-antibacterial calcium-chelating irrigant for removal of the inorganic component of the canal space debris, does not reduce the efficacy of either AMP.

Clinical Significance: The present study provides the proof of concept that incorporation of an antimicrobial peptide into a calcium-chelating root canal irrigant enhances the disinfection of intratubular single-species biofilms during smear layer and smear plug removal.
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http://dx.doi.org/10.1016/j.jdent.2019.103231DOI Listing
December 2019

Management of Large Radicular Lesions Using Decompression: A Case Series and Review of the Literature.

J Endod 2019 May 2;45(5):651-659. Epub 2019 Mar 2.

Department of Endodontics, The Dental College of Georgia, Augusta University, Augusta, Georgia. Electronic address:

The purpose of this study was to report the clinical efficacy of decompression for 3 cases with large periapical lesions and to review technique details. Three cases with large periapical cystic lesions were treated with decompression after root canal treatment. A traditional decompression technique was used for the first case. After aspiration, mucogingival incision, irrigation, and incisional biopsy, a pediatric endotracheal tube was sutured in place and kept for 3 weeks for lesion debridement. An aspiration/irrigation technique was adopted for the second case. An 18-G needle with a syringe was used to aspirate the cystic lesion. Two needles were then inserted into the lesion; copious saline irrigation was delivered from 1 needle and until clear saline was expressed from the other. For the third case, decompression was accomplished with a surgical catheter that was subsequently replaced with a gutta-percha plug after 1 month. None of the 3 cases underwent complete enucleation and root-end surgery. Healed lesions or lesions in healing were observed after 1 to 2 years. Based on the presented cases and published case reports on decompression, a literature review was provided covering indications, technique details, modification, and prognosis of decompression in endodontics. For large periapical cystic lesions, conservative decompression may be used for certain cases before or in lieu of apical surgery. Decompression enables healing of large, persistent periapical lesions after root canal treatment.
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http://dx.doi.org/10.1016/j.joen.2018.12.014DOI Listing
May 2019

Contribution of Mitophagy to Cell-Mediated Mineralization: Revisiting a 50-Year-Old Conundrum.

Adv Sci (Weinh) 2018 Oct 29;5(10):1800873. Epub 2018 Jul 29.

State Key Laboratory of Military Stomatology National Clinical Research Center for Oral Diseases Shaanxi Key Laboratory of Stomatology Department of Prosthodontics School of Stomatology The Fourth Military Medical University Xi'an 710032 P. R. China.

Biomineralization in vertebrates is initiated via amorphous calcium phosphate (ACP) precursors. These precursors infiltrate the extracellular collagen matrix where they undergo phase transformation into intrafibrillar carbonated apatite. Although it is well established that ACP precursors are released from intracellular vesicles through exocytosis, an unsolved enigma in this cell-mediated mineralization process is how ACP precursors, initially produced in the mitochondria, are translocated to the intracellular vesicles. The present study proposes that mitophagy provides the mechanism for transfer of ACP precursors from the dysfunctioned mitochondria to autophagosomes, which, upon fusion with lysosomes, become autolysosomes where the mitochondrial ACP precursors coalesce to form larger intravesicular granules, prior to their release into the extracellular matrix. Apart from endowing the mitochondria with the function of ACP delivery through mitophagy, the present results indicate that mitophagy, triggered upon intramitochondrial ACP accumulation in osteogenic lineage-committed mesenchymal stem cells, participates in the biomineralization process through the BMP/Smad signaling pathway.
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http://dx.doi.org/10.1002/advs.201800873DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6193168PMC
October 2018

Anti-biofilm efficacy of root canal irrigants against in-situ Enterococcus faecalis biofilms in root canals, isthmuses and dentinal tubules.

J Dent 2018 12 5;79:68-76. Epub 2018 Oct 5.

State Key Laboratory of Military Stomatology and National Clinical Research Center for Oral Diseases and Shaanxi Key Laboratory of Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, China; The Third Affiliated Hospital of Xinxiang Medical University, Xinxiang, Hena, China. Electronic address:

Objective: To investigate the anti-biofilm efficacy of root canal irrigants in canal spaces, isthmi and dentinal tubules of root canals ex vivo.

Methods: Fifty-one single-rooted premolars, each containing an isthmus, were instrumented, autoclaved and inoculated with Enterococcus faecalis for 4 weeks. One specimen was sectioned for bacteria-specific staining to confirm the presence of biofilms using light microscopiy. The remaining specimens were randomly divided to five groups: (1) 0.9% NaCl, (2) SilverSol/HO, (3) HYBENX, (4) QMix 2 in1, (5) 6% NaOCl. Bacterial sampling was performed before (S1) and after (S2) canal irrigation. Diluted bacteria suspension was cultured for 48 h for counting the colony forming units (CFU). Percentages of dead bacteria and biofilm thickness were evaluated by confocal laser scanning microscopy (CLSM). Metabolic activity, lactic acid and polysaccharide synthesis of E. faecalis derived from S2 samples were analysed.

Results: The percentages of dead bacteria were significantly affected by the factor "irrigant" (p < 0.001) and the factor "location" (p = 0.017). The percentages of dead bacteria in the isthmi and canals were both in the ordor: NaCl < SilverSol/HO < HYBENX < QMix 2 in1 < NaOCl (p < 0.05). Only 6% NaOCl disrupted biofilms and significantly reduced their thickness. The CFU, metabolic activity, polysaccharide and lactic acid production of E. faecalis were all reduced by the disinfecting solutions.

Conclusions: SilverSol/HO and HYBENX were less adept than QMix 2 in1 at killing biofilm bacteria in root canals. None of these antibacterial irrigants were effective, compared with 6% NaOCl, in disrupting biofilms.

Clinical Significance: There is advantage in using HYBENX or QMix 2 in1 to kill intratubular bacteria biofilms because of their capability in removing the inorganic component of the smear layer. SilverSol/HO requires extra time to eradicate intratubular biofilms upon removal of the organic and inorganic components of the smear layer by other root canal irrigants.
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http://dx.doi.org/10.1016/j.jdent.2018.10.002DOI Listing
December 2018

Effect of simulated intraosseous sinusoidal pressure on NaOCl extrusion.

J Dent 2018 11 2;78:46-50. Epub 2018 Aug 2.

Department of Endodontics, The Dental College of Georgia, Augusta University, Augusta, Georgia, USA; Department of Prosthodontics, School of Stomatology, Fourth Military Medical University, Xi'an, China. Electronic address:

Introduction: The present study examined the effects of irrigant flow rate and simulated intraosseous sinusoidal pressure on the rate of NaOCl extrusion from the apical terminus of a faux root canal.

Methods: An extrusion setup was designed to enable irrigant extrusion to be opposed by 30 mm Hg simulated intraosseous pressure. The faux canal apex was opposed by atmospheric + 30 mm Hg pressure (experimental) or atmospheric pressure only (control group). Using five irrigant delivery rates (15.6 8.0, 4.0, 3.4 or 3.0 mL/min), the extrusion rates of 2% NaOCl from the faux apex were measured in both groups (n = 16). Data were analysed with two-factor ANOVA and pairwise comparisons at α = 0.05. Correlation between NaOCl delivery rates and extrusion rates in both groups were analysed with the Pearson product-moment procedure.

Result: Irrespective of the presence or absence of simulated sinusoidal pressure, NaOCl extrusion rates were positively-correlated with irrigant flow rates. For the factor "irrigant flow rates", significant differences in NaOCl extrusion rates were identified among all flow rates (p < 0.05), except for the pairwise comparison between 4.0 and 3.4 mL/min in the control. For all irrigant flow rates, NaOCl extrusion rate was significantly lower in the presence of 30 mm Hg simulated sinusoidal pressure than that obtained in the absence of opposing pressure (p < 0.05).

Conclusion: In the presence of 30 mm Hg simulated intraosseous pressure, NaOCl delivered via a side-vented needle inserted to 1 mm short of working length may be prevented from extrusion when its flow rate is ≤ 3.0 mL/min.

Clinical Significance: When opposed by intraosseous sinusoidal pressure, NaOCl delivered via a side-vented needle inserted to 1 mm short of working length may be prevented from extrusion when its flow rate is ≤ 3.0 mL/min.
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http://dx.doi.org/10.1016/j.jdent.2018.08.001DOI Listing
November 2018

Antibacterial efficacy of an endodontic sonic-powered irrigation system: An in vitro study.

J Dent 2018 08 13;75:105-112. Epub 2018 Jun 13.

Department of Stomatology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China. Electronic address:

Objective: To evaluate the efficacy of EDDY, a new sonic-powered irrigation system, in reducing intracanal bacteria load.

Methods: Thirty-eight instrumented, autoclaved single-rooted human premolars were inoculated with Enterococcus faecalis (ATCC-29212) for 21 days. Two teeth were used as negative control without bacterial contamination. For the bacteria-inoculated teeth, 6 were used as positive control without irrigation. The remaining 30 teeth were randomly divided into 2 groups (N = 15), using 3% NaOCl as irrigant: (A) 30-gauge syringe needle irrigation (SNI), (B) EDDY (VDW, Munich, Germany). Twelve teeth per group and 4 teeth in the positive control were evaluated for bacterial reduction using MTT assay. The remaining teeth were split for BacLight LIVE/DEAD staining to examine the percentages of live/dead bacteria present in the dentinal tubules from different canal locations (coronal, mid-root and apical portions of the canal space) using confocal laser scanning microscopy (CLSM).

Results: MTT assay indicated that both SNI and EDDY significantly reduced overall intracanal bacterial load compared with the positive control, with no significant difference between the two techniques. CLSM indicated that EDDY had better intratubular bacterial killing efficacy than SNI in the coronal and mid-root portions of the canal space only but not in the apical portion. In all canal locations (coronal, mid-root apical), both systems failed to eliminate bacteria that proliferated deep within the dentinal tubules.

Conclusion: With the use of 3% NaOCl, sonic-powered irrigant activation with EDDY tips did not provide additional advantage over SNI in killing Enterococcus faecalis from deep intraradicular dentin.

Clinical Significance: Both the sonic-powered root canal irrigant activation system and syringe needle irrigation can reduce intracanal bacteria load but are incapable of completely killing all bacteria that resided deep within the dentinal tubules of root canals infected with Enterococcus faecalis.
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http://dx.doi.org/10.1016/j.jdent.2018.06.003DOI Listing
August 2018

Antimicrobial efficacy of an apical negative pressure root canal irrigation system against intracanal microorganisms.

J Dent 2018 05 20;72:71-75. Epub 2018 Mar 20.

The Dental College of Georgia, Augusta University, Augusta, GA, USA; Department of Prosthodontics, School of Stomatology, Fourth Military Medical University, Xi'an, China. Electronic address:

Objectives: The effect of irrigation time on the antimicrobial efficacy of an apical negative pressure irrigation system was examined in vitro, followed by validation of the antimicrobial effect in vivo using the identified optimal irrigation time.

Methods: For the in vitro experiment, 44 extracted premolars were decoronated, instrumented, autoclaved and inoculated with Enterococcus faecalis (ATCC 29212) for 21 days. Four teeth were used as positive control, without irrigation. Each of the remaining 40 teeth was irrigated with 2.5% NaOCl, delivered via the EndoVac MacroCannula for 10 s, and subsequently via the EndoVac MicroCannula for 15, 30, 45, 60 or 90 s per canal, respectively (N = 8). After irrigation, microbial samples were collected, transferred to BHI broth and incubated for counting of bacterial colony forming units (CFUs). Based on the in vitro results, 8.25% NaOCl was delivered via the EndoVac MicroCannula for 60 s, during root canal treatment of 20 human subjects presented with apical periodontitis. Microbial samples retrieved in vivo prior to canal instrumentation (S0), after chemomechanical debridement (S1) and after irrigation with EndoVac (S2) were cultured in an anaerobic chamber for 7 days for CFU evaluation.

Results: Compared with the control, irrigation significantly reduced bacterial populations (p < .05). Irrigation delivery via the EndoVac demonstrated improved antibacterial efficacy with increased irrigation time (p < .05). Samples retrieved from canals after NaOCl delivery in vivo with the EndoVac for 60 s were all culture-negative.

Conclusions: Microbial elimination may be achieved with 8.25% NaOCl delivered via the EndoVac apical negative pressure irrigation device for 60 s.

Clinical Significance: With the use of the EndoVac apical negative pressure irrigant delivery system, optimal elimination of the intracanal bacterial load can only be achieved when sodium hypochlorite is delivered via the MicroCannula for at least 60 s per canal.
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http://dx.doi.org/10.1016/j.jdent.2018.03.008DOI Listing
May 2018

Mechanism of bioactive molecular extraction from mineralized dentin by calcium hydroxide and tricalcium silicate cement.

Dent Mater 2018 02 24;34(2):317-330. Epub 2017 Nov 24.

State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Oral Diseases, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, PR China. Electronic address:

Objectives: The objective of the present study was to elucidate the mechanism of bioactive molecule extraction from mineralized dentin by calcium hydroxide (Ca(OH)) and tricalcium silicate cements (TSC).

Methods And Results: Transmission electron microscopy was used to provide evidence for collagen degradation in dentin surfaces covered with Ca(OH) or a set, hydrated TSC for 1-3 months. A one micron thick collagen degradation zone was observed on the dentin surface. Fourier transform-infrared spectroscopy was used to identify increases in apatite/collagen ratio in dentin exposed to Ca(OH). Using three-point bending, dentin exposed to Ca(OH) exhibited significant reduction in flexural strength. Using size exclusion chromatography, it was found that the small size of the hydroxyl ions derived from Ca(OH) enabled those ions to infiltrate the intrafibrillar compartment of mineralized collagen and degrade the collagen fibrils without affecting the apatite minerals. Using ELISA, TGF-β1 was found to be extracted from dentin covered with Ca(OH) for 3 months. Unlike acids that dissolve the mineral component of dentin to release bioactive molecules, alkaline materials such as Ca(OH) or TSC released growth factors such as TGF-β1 via collagen degradation.

Significance: The bioactive molecule extraction capacities of Ca(OH) and TSC render these dental materials excellent for pulp capping and endodontic regeneration. These highly desirable properties, however, appear to be intertwined with the untoward effect of degradation of the collagen matrix within mineralized dentin, resulting in reduced flexural strength.
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http://dx.doi.org/10.1016/j.dental.2017.11.010DOI Listing
February 2018

Effect of Canal Anastomosis on Periapical Fluid Pressure Build-up during Needle Irrigation in Single Roots with Double Canals using a Polycarbonate Model.

Sci Rep 2017 05 8;7(1):1582. Epub 2017 May 8.

Department of Endodontics, The Dental College of Georgia, Augusta University, Georgia, USA.

Sodium hypochlorite is an effective irrigant for chemical debridement of root canals. However, increasing the intracanal pressure during irrigant delivery may result in irrigant extrusion into the bone and soft tissues surrounding the tooth. Because clinicians often encounter teeth with intracanal communications, the objective of the present study was to examine the effects of canal anastomosis on the generation of periapical fluid pressure at different fluid flow rates and insertion depths. Two similar polycarbonate models were used to simulate a single root with double canals, one containing, and the other without communicating channels between the canals. For both models, periapical pressure increased with increasing irrigant flow rates and insertion depths of a 30-gauge side-venting needle. In the presence of communicating channels, the magnitude of pressure build-up decreased by almost 90% irrespective of the fluid flow rate or needle insertion depth. Pressure reduction in anastomoses-containing roots provides an explanation why pressure generation in single roots is considerably higher. Nevertheless, it is still possible in teeth with canal anastomoses for pressure exceeding the intraosseous pressure to be generated when the fluid flow rate is sufficiently high and when the needle tip is close to the apical terminus.
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http://dx.doi.org/10.1038/s41598-017-01697-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5431501PMC
May 2017

Potential applications of antimicrobial peptides and their mimics in combating caries and pulpal infections.

Acta Biomater 2017 02 11;49:16-35. Epub 2016 Nov 11.

Department of Endodontics, The Dental College of Georgia, Augusta University, GA, USA. Electronic address:

Antimicrobial peptides (AMPs) are short cationic host-defense molecules that provide the early stage of protection against invading microbes. They also have important modulatory roles and act as a bridge between innate and acquired immunity. The types and functions of oral AMPs were reviewed and experimental reports on the use of natural AMPs and their synthetic mimics in caries and pulpal infections were discussed. Natural AMPs in the oral cavity, predominantly defensins, cathelicidins and histatins, possess antimicrobial activities against oral pathogens and biofilms. Incomplete debridement of microorganisms in root canal space may precipitate an exacerbated immune response that results in periradicular bone resorption. Because of their immunomodulatory and wound healing potentials, AMPs stimulate pro-inflammatory cytokine production, recruit host defense cells and regulate immuno-inflammatory responses in the vicinity of the pulp and periapex. Recent rapid advances in the development of synthetic AMP mimics offer exciting opportunities for new therapeutic initiatives in root canal treatment and regenerative endodontics.

Statement Of Significance: Identification of new therapeutic strategies to combat antibiotic-resistant pathogens and biofilm-associated infections continues to be one of the major challenges in modern medicine. Despite the presence of commercialization hurdles and scientific challenges, interests in using antimicrobial peptides as therapeutic alternatives and adjuvants to combat pathogenic biofilms have never been foreshortened. Not only do these cationic peptides possess rapid killing ability, their multi-modal mechanisms of action render them advantageous in targeting different biofilm sub-populations. These factors, together with adjunctive bioactive functions such as immunomodulation and wound healing enhancement, render AMPs or their synthetic mimics exciting candidates to be considered as adjuncts in the treatment of caries, infected pulps and root canals.
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http://dx.doi.org/10.1016/j.actbio.2016.11.026DOI Listing
February 2017

Mineralogenic characteristics of osteogenic lineage-committed human dental pulp stem cells following their exposure to a discoloration-free calcium aluminosilicate cement.

Dent Mater 2016 10 3;32(10):1235-1247. Epub 2016 Aug 3.

Department of Endodontics, The Dental College of Georgia, Augusta University, Augusta, GA, USA. Electronic address:

Objectives: An experimental discoloration-free calcium aluminosilicate cement has been developed with the intention of maximizing the beneficial attributes of tricalcium silicate cements and calcium aluminate cements. The present study examined the effects of this experimental cement (Quick-Set2) on the mineralogenic characteristics of osteogenic lineage-committed human dental pulp stem cells (hDPSCs), by comparing the cellular responses with a commercially available tricalcium silicate cement (white mineral trioxide aggregate (ProRoot(®) MTA); WMTA).

Methods: The osteogenic potential of hDPSCs exposed to the cements was examined using qRT-PCR for osteogenic gene expressions, Western blot for osteogenic-related protein expressions, alkaline phosphatase enzyme activity, Alizarin red S staining, Fourier transform infrared spectroscopy and transmission electron microscopy of extracellular calcium deposits.

Results: Results of the six assays indicated that osteogenic differentiation of hDPSCs was significantly enhanced after exposure to the tricalcium silicate cement or the experimental calcium aluminosilicate cement, with the former demonstrating better mineralogenic stimulation capacity.

Significance: The better osteogenic stimulating effect of the tricalcium silicate cement on hDPSCs may be due to its relatively higher silicate content, or higher OH(-) and Ca(2+) release. Further investigations with the use of in vivo animal models are required to validate the potential augmenting osteogenic effects of the experimental discoloration-free calcium aluminosilicate cement.
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http://dx.doi.org/10.1016/j.dental.2016.07.007DOI Listing
October 2016

Effects of a discoloration-resistant calcium aluminosilicate cement on the viability and proliferation of undifferentiated human dental pulp stem cells.

Sci Rep 2015 Nov 30;5:17177. Epub 2015 Nov 30.

Department of Endodontics, Georgia Regents University, Augusta, Georgia, USA.

Discoloration-resistant calcium aluminosilicate cement has been formulated to overcome the timely problem of tooth discoloration reported in the clinical application of bismuth oxide-containing hydraulic cements. The present study examined the effects of this experimental cement (Quick-Set2) on the viability and proliferation of human dental pulp stem cells (hDPSCs) by comparing the cellular responses with commercially available calcium silicate cement (white mineral trioxide aggregate; WMTA) after different aging periods. Cell viability and proliferation were examined using assays that examined plasma membrane integrity, leakage of cytosolic enzyme, caspase-3 activity for early apoptosis, oxidative stress, mitochondrial metabolic activity and intracellular DNA content. Results of the six assays indicated that both Quick-Set2 and WMTA were initially cytotoxic to hDPSCs after setting for 24 h, with Quick-Set2 being comparatively less cytotoxic than WMTA at this stage. After two aging cycles, the cytotoxicity profiles of the two hydraulic cements were not significantly different and were much less cytotoxic than the positive control (zinc oxide-eugenol cement). Based on these results, it is envisaged that any potential beneficial effect of the discoloration-resistant calcium aluminosilicate cement on osteogenesis by differentiated hDPSCs is more likely to be revealed after outward diffusion and removal of its cytotoxic components.
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http://dx.doi.org/10.1038/srep17177DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4663481PMC
November 2015

Evaluation of 4 Different Irrigating Systems for Apical Extrusion of Sodium Hypochlorite.

J Endod 2015 Sep 2;41(9):1530-4. Epub 2015 Jul 2.

Louisiana State University, New Orleans, Louisiana.

Introduction: The aim of this study was to evaluate NaOCl apical extrusion by using negative apical pressure (EndoVac), sonic agitation (EndoActivator), side-vented needle (Max-i-Probe), and photon induced photoacoustic streaming (PIPS 10 mJ and PIPS 20 mJ) laser irrigation in an in vitro gel model.

Methods: Extracted mandibular and maxillary central incisors (n = 18) were prepared to size 35/.04 and 55/.04, respectively. Teeth were mounted in transparent containers with clear acrylic and suspended in a color-changing pH-sensitive gel, creating a closed system. By using a crossover design, each tooth was sequentially irrigated by using 6% NaOCl with each device following manufacturers' recommendations. Each tooth served as its own control. Pre-irrigation and post-irrigation buccal and proximal view photographs served to measure the longest distance of extrusion and were analyzed with ImageJ software. Mean results were analyzed by using Kruskal-Wallis and Dunn post hoc test (P < .05).

Results: There were no significant differences between EndoVac, EndoActivator, and the passive extrusion groups. The EndoVac and EndoActivator groups produced significantly less extrusion than PIPS irrigation. Max-i-Probe extrusion results were more variable than those of EndoActivator but had no significant difference. Across all irrigation systems, there were no significant differences with respect to apical preparation size.

Conclusions: Under the in vitro conditions of this study, no difference was found between the 10 mJ and 20 mJ PIPS laser groups. EndoVac demonstrated significantly less potential for apical extrusion than PIPS and Max-i-Probe, whereas apical preparation size did not significantly affect extrusion of irrigant. The potential for apical extrusion of endodontic irrigants should be a consideration when selecting a system for final irrigation.
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http://dx.doi.org/10.1016/j.joen.2015.05.007DOI Listing
September 2015

Effect of repeated simulated clinical use and sterilization on the cutting efficiency and flexibility of Hyflex CM nickel-titanium rotary files.

J Endod 2015 May 3;41(5):725-8. Epub 2015 Mar 3.

Department of Endodontics, Louisiana State University, New Orleans, Louisiana.

Introduction: Recent nickel-titanium manufacturing processes have resulted in an alloy that remains in a twinned martensitic phase at operating temperature. This alloy has been shown to have increased flexibility with added tolerance to cyclic and torsional fatigue. The aim of this study was to assess the effect of repeated simulated clinical use and sterilization on cutting efficiency and flexibility of Hyflex CM rotary files.

Methods: Cutting efficiency was determined by measuring the load required to maintain a constant feed rate while instrumenting simulated canals. Flexibility was determined by using a 3-point bending test. Files were autoclaved after each use according to the manufacturer's recommendations. Files were tested through 10 simulated clinical uses. For cutting efficiency, mean data were analyzed by using multiple factor analysis of variance and the Dunnett post hoc test (P < .05). For flexibility, mean data were analyzed by using Levene's Test of Equality of Error and a general linear model (P < .05).

Results: No statistically significant decrease in cutting efficiency was noted in groups 2, 5, 6, and 7. A statistically significant decrease in cutting efficiency was noted in groups 3, 4, 8, 9, and 10. No statistically significant decrease in flexibility was noted in groups 2, 3, and 7. A statistically significant decrease in flexibility was noted in groups 4, 5, 6, 8, 9, 10, and 11.

Conclusions: Repeated simulated clinical use and sterilization showed no effect on cutting efficiency through 1 use and no effect on flexibility through 2 uses.
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http://dx.doi.org/10.1016/j.joen.2015.01.011DOI Listing
May 2015

Efficacy of 3D conforming nickel titanium rotary instruments in eliminating canal wall bacteria from oval-shaped root canals.

J Dent 2015 May 13;43(5):597-604. Epub 2015 Jan 13.

College of Dental Medicine, Georgia Regents University, Augusta, GA, USA. Electronic address:

Objectives: To evaluate the effectiveness of TRUShape® 3D Conforming Files, compared with Twisted Files, in reducing bacteria load from root canal walls, in the presence or absence of irrigant agitation.

Methods: Extracted human premolars with single oval-shaped canals were infected with Enterococcus faecalis. Teeth in Group I (N=10; NaOCl and QMix® 2in1 as respective initial and final irrigants) were subdivided into 4 subgroups: (A) TRUShape® instrumentation without irrigant activation; (B) TRUShape® instrumentation with sonic irrigant agitation; (C) Twisted Files without irrigant agitation; (D) Twisted Files with sonic irrigant agitation. To remove confounding factor (antimicrobial irrigants), teeth in Group II (N=10) were irrigated with sterile saline, using the same subgroup designations. Specimens before and after chemomechanical débridement were cultured for quantification of colony-forming units (CFUs). Data from each group were analyzed separately using two-factor ANOVA and Holm-Sidak multiple comparison (α=0.05). Canal wall bacteria were qualitatively examined using scanning electron microscopy (SEM) and light microscopy of Taylor-modified Brown and Brenn-stained demineralised sections.

Results: CFUs from subgroups in Group I were not significantly different (P=0.935). For Group II, both file type (P<0.001) and irrigant agitation (P<0.001) significantly affected log-reduction in CFU concentrations. The interaction of these two factors was not significant (P=0.601). Although SEM showed reduced canal wall bacteria, bacteria were present within dentinal tubules after rotary instrumentation, as revealed by light microscopy of longitudinal root sections.

Conclusions: TRUShape® files removed significantly more canal wall bacteria than Twisted Files when used without an antibacterial irrigant; the latter is required to decontaminate dentinal tubules.

Clinical Significance: Root canal disinfection should not be focused only on a mechanistic approach. Rather, the rational choice of a rotary instrumentation system should be combined with the use of well-tested antimicrobial irrigants and delivery/agitation techniques to establish a clinically realistic chemomechanical débridement protocol.
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http://dx.doi.org/10.1016/j.jdent.2015.01.001DOI Listing
May 2015

Quality of obturation achieved by a non-gutta-percha-based root filling system in single-rooted canals.

J Endod 2014 Dec 26;40(12):2003-8. Epub 2014 Sep 26.

Department of Endodontics, Georgia Regents University, Augusta, Georgia. Electronic address:

Introduction: The present study examined the quality of obturation in root canals filled by an experimental non-gutta-percha-based (NGP) root filling system using warm vertical or cold lateral compaction. The quality of obturation was evaluated by comparing the volumetric percentage of gaps and voids identified from similar canals obturated with gutta-percha and an epoxy resin-based sealer using the same obturation techniques.

Methods: Forty single-rooted premolars with oval-shaped canals were cleaned, shaped, and obturated with 1 of the 4 material/obturation technique combinations (n = 10). Filled canals were scanned with micro-computed tomographic imaging. Reconstructed images were analyzed for the volumetric percentage of gaps and voids at 3 canal levels (0-4, 4-8, and 8-12 mm from the working length). Roots were sectioned at the 4-mm, 8-mm, and 12-mm levels. Scanning electron microscopic images of negative replicas of root sections were examined to quantify the circumferential percentage of interfacial gaps and the area percentage of intracanal voids. Data were analyzed with parametric or nonparametric statistical methods.

Results: A statistically significant difference was found for the volumetric percentage distribution of gaps and voids for "obturation technique" but not for "material." Significantly higher percentages of gaps and voids were identified in canals obturated with the NGP system using cold lateral compaction. Examination of negative replicas ascribed this difference to a higher area percentage of interfacial gaps rather than more intracanal voids.

Conclusions: Using warm vertical compaction, the NGP system fulfils the objective of 3-dimensional obturation of the canal space in a manner comparable with the results achieved with gutta-percha and a root canal sealer.
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http://dx.doi.org/10.1016/j.joen.2014.07.032DOI Listing
December 2014

Quality of obturation achieved by an endodontic core-carrier system with crosslinked gutta-percha carrier in single-rooted canals.

J Dent 2014 Sep 24;42(9):1124-34. Epub 2014 Apr 24.

Department of Endodontics, Georgia Regents University, Augusta, GA, USA. Electronic address:

Objectives: The present study examined the quality of obturation in root canals obturated by GuttaCore, a gutta-percha-based core-carrier system with a cross-linked thermoset gutta-percha carrier, by comparing the incidence of gaps and voids identified from similar canals obturated by cold lateral compaction or warm vertical compaction.

Methods: Thirty single-rooted premolars with oval-shaped canals were shaped and cleaned, and obturated with one of the three obturation techniques (N=10): GuttaCore, warm vertical compaction or cold lateral compaction. Filled canals were scanned with micro-computed tomography (micro-CT); reconstructed images were analysed for the volumetric percentage of gaps and voids at three canal levels (0-4mm, 4-8mm and 8-12mm from working length). The roots were subsequently sectioned at the 4-mm, 8-mm and 12-mm levels for analyses of the percentage of interfacial gaps, and area percentage of interfacial and intracanal voids, using scanning electron microscopy (SEM) to examine negative replicas of root sections. Data were analysed with parametric or non-parametric statistical methods at α=0.05.

Results: Both micro-CT and SEM data indicated that canals obturated with GuttaCore core-carriers had the lowest incidence of interfacial gaps and voids, although the results were not significantly different from canals obturated by warm vertical compaction. Both the GuttaCore and the warm vertical compaction groups, in turn, had significantly lower incidences of gaps and voids than the cold lateral compaction group.

Conclusions: Because of the similarity in obturation quality between GuttaCore and warm vertical compaction, practitioners may find the GuttaCore core-carrier technique a valuable alternative for obturation of oval-shaped canals.

Clinical Significance: The quality of obturation achieved by GuttaCore in single-rooted canals is not significantly different from that achieved by warm vertical compaction.
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http://dx.doi.org/10.1016/j.jdent.2014.04.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4134970PMC
September 2014

A review of the bioactivity of hydraulic calcium silicate cements.

J Dent 2014 May 15;42(5):517-33. Epub 2014 Jan 15.

Department of Endodontics, College of Dental Medicine, Georgia Regents University, Augusta, GA, USA; College of Graduate Studies, Georgia Regents University, Augusta, GA, USA. Electronic address:

Objectives: In tissue regeneration research, the term "bioactivity" was initially used to describe the resistance to removal of a biomaterial from host tissues after intraosseous implantation. Hydraulic calcium silicate cements (HCSCs) are putatively accepted as bioactive materials, as exemplified by the increasing number of publications reporting that these cements produce an apatite-rich surface layer after they contact simulated body fluids.

Methods: In this review, the same definitions employed for establishing in vitro and in vivo bioactivity in glass-ceramics, and the proposed mechanisms involved in these phenomena are used as blueprints for investigating whether HCSCs are bioactive.

Results: The literature abounds with evidence that HCSCs exhibit in vitro bioactivity; however, there is a general lack of stringent methodologies for characterizing the calcium phosphate phases precipitated on HCSCs. Although in vivo bioactivity has been demonstrated for some HCSCs, a fibrous connective tissue layer is frequently identified along the bone-cement interface that is reminiscent of the responses observed in bioinert materials, without accompanying clarifications to account for such observations.

Conclusions: As bone-bonding is not predictably achieved, there is insufficient scientific evidence to substantiate that HCSCs are indeed bioactive. Objective appraisal criteria should be developed for more accurately defining the bioactivity profiles of HCSCs designed for clinical use.
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http://dx.doi.org/10.1016/j.jdent.2013.12.015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3995854PMC
May 2014

Misdiagnosis of a nasopalatine duct cyst: a case report.

J Endod 2013 Sep 14;39(9):1185-8. Epub 2013 Jun 14.

Aviano AFB, Aviano, Italy.

Introduction: Nonendodontic lesions misdiagnosed as pathoses of endodontic origin are often referenced in the literature. One of the most frequent nonodontogenic cysts of the oral cavity, the nasopalatine duct cyst (NPDC), can be misdiagnosed as endodontic in nature.

Methods: A case is presented in which a patent NPDC was originally diagnosed as a sinus tract with subsequent endodontic nonsurgical retreatment and eventual extraction before endodontic consultation.

Results: After surgical treatment, a histopathologic diagnosis of an NPDC was confirmed.

Conclusions: If diagnosed incorrectly, inappropriate endodontic treatment of a NPDC may be initiated to include unnecessary extraction. An increased understanding of anatomy, the use of appropriate diagnostic tests to include cone-beam computed tomography imaging, and key examination techniques to distinguish endodontic lesions from nonendodontic pathoses are imperative for an accurate differential diagnosis and appropriate treatment outcome.
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http://dx.doi.org/10.1016/j.joen.2013.04.033DOI Listing
September 2013

Shaping ability of three nickel-titanium endodontic file systems in simulated S-shaped root canals.

J Endod 2012 Dec 18;38(12):1618-21. Epub 2012 Oct 18.

Department of Endodontics, Keesler Medical Center, Keesler Air Force Base, Mississippi 39534, USA.

Introduction: The purpose of this study was to determine the shaping ability of 3 nickel-titanium (NiTi) endodontic file systems by measuring canal transportation.

Methods: Seventy-two S-shaped canals in resin blocks were randomly allocated into 3 groups (n = 24): the Self-Adjusting File (SAF; ReDent Nova, Ra'anana, Israel) group, the Typhoon group (Typhoon rotary files with Controlled Memory Wire; DS Dental, Johnson City, TN), and the Vortex group (ProFile Vortex rotary files with M-Wire NiTi; Dentsply Tulsa Dental Specialties, Tulsa, OK). Blocks were secured in a jig for imaging standardization and instrumentation stabilization. Gates Glidden and PathFile drills (25 mm/.02 taper) were used to prepare the glide paths. For the Typhoon and Vortex groups (25 mm/.04 taper), canals were flooded with sterile water and instrumented using a crown-down technique from sizes 40 to 20/.04 and then apically enlarged to size 30/.04. The SAF group (25 mm) was instrumented with constant sterile water irrigation in a light-pecking, transline motion. Pre- and postinstrumentation images were taken at 40× magnification and layered, and canal transportation was measured.

Results: After adjusting for the level and canal wall side, the mean transportation was significantly higher for the Typhoon (P < .001) and Vortex (P = .005) groups compared with the SAF group. Additionally, the mean transportation was significantly higher for the Typhoon group versus the Vortex group (P < .001).

Conclusions: Under the conditions of this study, SAFs showed less canal transportation than ProFile Vortex and Typhoon files in simulated S-shaped root canals.
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http://dx.doi.org/10.1016/j.joen.2012.09.011DOI Listing
December 2012

Comparison of autoclaving effects on torsional deformation and fracture resistance of three innovative endodontic file systems.

J Endod 2011 Nov 9;37(11):1572-5. Epub 2011 Sep 9.

Department of Endodontics, Keesler Medical Center, Keesler Air Force Base, Mississippi, USA.

Introduction: Recent innovative manufacturing techniques have produced nickel-titanium (NiTi) rotary instruments with reports of superior properties compared with standard NiTi files. These include Profile Vortex made from M-Wire (PV), Twisted Files (TF), and 10 Series files made from CM Wire (CM). Sterilization is recommended before use and is repeated if files are reused and/or carried forward between cases. The purpose for this study was to compare the effects of multiple autoclaving cycles on the torsional load resistance of these 3 new rotary endodontic files.

Methods: PV, TF, and CM files (n = 100; size 25/.04) were divided into 5 groups (n = 20). Files were steam autoclaved for 1, 2, 3, and 7 sterilization cycles. A control group was not subjected to autoclaving. Files were tested in a torsiometer in general accordance with ISO 3630-1 standards. Torsional load and degrees of rotation to failure were recorded. Mean data were analyzed by using Kruskal-Wallace/Dunn post hoc tests (P < .05).

Results: Autoclave cycles had no significant overall effect on file performance for any of the instrument systems tested. PV and CM displayed significantly greater resistance to torsional load than TF (P < .001) but were not different from each other (P > .05). Angular deflection values for TF and CM were significantly higher than for PV (P < .001), with TF demonstrating greater rotational distortion than CM (P < .05).

Conclusions: Under the conditions of this study, repeated steam autoclaving did not affect torsional resistance for unused files of the systems evaluated. In addition, CM Wire files might have a combined advantage of greater torsional strength and high deformation before failure.
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http://dx.doi.org/10.1016/j.joen.2011.07.008DOI Listing
November 2011

Multiple autoclave cycle effects on cyclic fatigue of nickel-titanium rotary files produced by new manufacturing methods.

J Endod 2011 Jan;37(1):72-4

Department of Endodontics, Keesler Medical Center, Keesler AFB, MS 39534, USA.

Introduction: Novel nickel-titanium rotary files with proprietary manufacturing techniques have recently been marketed. The purpose of this study was to assess multiple autoclave cycle effects on cyclic fatigue of GT Series X files (Dentsply Tulsa Dental Specialties, Tulsa, OK) and Twisted Files (SybronEndo, Orange, CA) METHODS: A jig using a 5-mm radius curve with 90° of maximum file flexure was used to induce cyclic fatigue failure. Files (n = 10) representing each experimental group (GT Series X 20/.04 and 20/.06; Twisted Files 25/.04 and 25/.06) were first tested to establish baseline mean cycles to failure (MCF). Experimental groups (n = 20) were then cycled to 25% of the established baseline MCF and then autoclaved. Additional autoclaving was accomplished at 50% and 75% of MCF followed by continual testing until failure. Control groups (n = 20) underwent the same procedures except autoclaving was not accomplished.

Results: The GT Series X (20/.04 and 20/.06) files showed no significant difference (p = 0.918/p = 0.096) in MCF for experimental versus control files. Twisted Files (25/.04) showed no significant difference (p = 0.432) in MCF between experimental and control groups. However, the Twisted Files (25/.06) experimental group showed a significantly lower (p = 0.0175) MCF compared with the controls.

Conclusions: Under the conditions of this evaluation, autoclave sterilization significantly decreased cyclic fatigue resistance of one of the four file groups tested. Repeated autoclaving significantly reduced the MCF of 25/.06 Twisted Files; however, 25/.04 Twisted Files and both GT Series X files tested were not significantly affected by the same conditions.
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http://dx.doi.org/10.1016/j.joen.2010.09.011DOI Listing
January 2011

Apical leakage of root-end placed SuperEBA, MTA, and Geristore restorations in human teeth previously stored in 10% formalin.

J Endod 2006 Oct;32(10):956-9

Department of Endodontics, Keesler Medical Center, Keesler AFB, Biloxi, Mississippi 39534-2567, USA.

The purpose of this study was to determine if storage of extracted teeth in 10% formalin affects microleakage of MTA, Geristore, or SuperEBA root-end fillings. There were 130 freshly extracted single-rooted teeth collected, immediately placed in phosphate buffered saline (PBS) and stored for less than 24 hours. Teeth were divided and either placed in 10% formalin for a 4-weeks immersion or immediately prepared. Preparation for all teeth consisted of canal instrumentation, obturation, apical resection, retrograde preparation, and placement of a root-end filling material. After 72 hours, the apical portions were immersed in India ink under vacuum pressure for 30 minutes, and then stored in ink for 1 week. Negative controls and positive controls performed as expected. In general, there was significantly less dye leakage of root-end restorations in teeth stored in 10% formalin when compared to the freshly extracted teeth (p < 0.0001). No difference in dye leakage was observed between Geristore restorations placed in teeth stored in formalin as compared to fresh teeth (p = 0.892). Less dye leakage was noted in teeth restored with Geristore as compared to MTA and SuperEBA, regardless of storage medium (p < 0.0001). No difference was observed between MTA and SuperEBA root-end restorations (p = 0.157). The results of this study provide evidence that storage of teeth in 10% formalin over a 4-week period may significantly influence dye leakage as compared to leakage in freshly extracted teeth.
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http://dx.doi.org/10.1016/j.joen.2006.07.011DOI Listing
October 2006

The effect of formalin storage on the apical microleakage of obturated canals.

J Endod 2006 Sep 7;32(9):869-71. Epub 2006 Jul 7.

Department of Endodontics, Keesler Medical Center, Keesler AFB, Biloxi, Mississippi 39534-2567, USA.

Infection control guidelines recommend disinfection of extracted teeth in 10% formalin for 2 weeks before use. Although extracted teeth are routinely used for in vitro endodontic research, the potential influence of formalin has not been evaluated. The purpose of this study was to investigate the effect of formalin storage on the apical seal integrity of obturated canals. There were 100 single-rooted human teeth decoronated, accessed, and randomly divided into four groups. Group 1 was composed of specimens that were instrumented and obturated after extraction without storage in formalin. Groups 2, 3, and 4 were stored in formalin for 2, 4, and 8 weeks, respectively, before treatment. Canals were instrumented to a master apical file size #7 ProFile .04 Taper Series 29 and obturated with Obtura II thermoplasticized gutta-percha and Roth 801 sealer. The teeth were immersed in India ink, cleared, and the greatest extent of linear dye leakage was measured. Microleakage testing displayed significantly less microleakage after 2 and 4 weeks of formalin storage. Leakage measurements after 4 weeks of storage were 62.3% lower than nonfixed specimens. The 8-week storage group demonstrated lower dye penetration compared with the nonfixed group; however, the difference was not statistically significant. Within the scope of this study, storage of extracted teeth in formalin for 2 and 4 weeks resulted in a significant decrease in apical microleakage compared with nonfixed specimens.
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http://dx.doi.org/10.1016/j.joen.2006.04.009DOI Listing
September 2006
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