A New Solution for the Removal of the Smear Layer
Mahmoud Torabinejad, Abbas Ali Khademi, Jalil Babagoli, Yongbum Cho, William Ben Johnson, Krassimir Bozhilov, Jay Kim, and Shahrokh Shabahang
Histopathological Study of Dental Pulp Tissue Capped with Enamel Matrix Derivative
Nelson Tatsunari Ishizaki, Koukichi Matsumoto, Yuichi Kimura, Xiaogu Wang, and Akinori Yamashita
Detection of Vascular Endothelial Growth Factor/Vascular Permeability Factor in Periapical Lesions
R. Leonardi, M. Caltabiano, M. Pagano, V. Pezzuto, C. Loreto, and G. Palestro
Human Periodontal Ligament Cell Viability in Milk and Milk Substitutes
Robert M. Pearson, Frederick R. Liewehr, Leslie A. West, William R. Patton, James C. McPherson, III, and Royce R. Runner
In Vitro Antimicrobial Activity of Various Medication Preparations on E. faecalis in Root Canal Dentin
Richard E. Lynne, Frederick R. Liewehr, Lesley A. West, William R. Patton, Thomas B. Buxton, and James C. McPherson, III
Shearing Bond Strength of Endodontic Sealers to Gutta-percha
Michael Tagger, Etty Tagger, Anthony H. L. Tjan, and Leif K. Bakland
An Immunohistological Study of the Localization of Bacterial Invading Root Pulpal Walls of Teeth with Periapical Lesions
Takashi Matsuo, Toshiyuki Shirakami, Kazumi Ozaki, Tadashi Nakanishi, Hiromichi Yumoto, and Shigeyuki Ebisu
Proinflammatory Cytokines Induce Cyclooxygenase-2 mRNA and Protein Expression in Human Pulp Cell Cultures
Yu-Chao Chang, M Shun-Fa Yang, Fu-Mei Huang, M Chia-Ming Liu, Kuo-Wei Tai, and Yih-Shou Hsieh
Bilateral Oroantral Fistulas Following Devitalization Of Teeth By Arsenic Trioxide: A Case Report
Serhat Yalçin, Buket Aybar, Faruk Haznedaroğlu, and Emre Yǘcel
Apical Leakage of Four Endodontic Sealers
Ludovic Pommel, Imad About, David Pashley, and Jean Camps
In Vitro Inhibitory Effect of EGTA on Macrophage Adhesion: Endodontic Implications
Juan J. Segura-Egea, Alicia Jiménez-Rubio, José V. Rios-Santos, Eugenio Velasco-Ortega, and Juan R. Clavo-Gutierrez
The Cemento-Dentino-Canal Junction, the Apical Foramen, and the Apical Constriction: Evaluation by Optical Microscopy
Elías Harrán Ponce, and José Antonio Vilar Fernández
A New Solution for the Removal of the Smear Layer
Mahmoud Torabinejad, DMD, MSD, PhD, Abbas Ali Khademi, DMD, MS, Jalil Babagoli, DMD, Yongbum Cho, DDS, MS, PhD, William Ben Johnson, DDS, Krassimir Bozhilov, PhD, Jay Kim, PhD, and Shahrokh Shabahang, DDS, MS, PhD
Various organic acids, ultrasonic instruments, and lasers have been used to remove the smear layer from the surface on instrumented root canals. The purpose of this study was to investigate the effect of a mixture of a tetracycline isomer, an acid, and a detergent (MTAD) as a final rinse on the surface of instrumented root canals. Forty-eight extracted maxillary and mandibular single-rooted human teeth were prepared by using a combination of passive step-back and rotary 0.04 taper nickel-titanium files. Sterile distilled water or 5.25% sodium hypochlorite was used as intracanal irrigant. The canals were then treated with 5 ml of one of the following solutions as a final rinse: sterile distilled water, 5.25% sodium hypochlorite, 17 % EDTA, or a new solution, MTAD. The presence or absence of smear layer and the amount of erosion on the surface of the root canal walls at the coronal, middle, and apical portion of each canal were examined under a scanning electron microscope. The results show that MTAD is an effective solution for the removal of the smear layer and does not significantly change the structure of the dentinal tubules when canals are irrigated with sodium hypochlorite and followed with a final rinse of MTAD.
Histopathological Study of Dental Pulp Tissue Capped with Enamel Matrix Derivative
Nelson Tatsunari Ishizaki, DDS, Koukichi Matsumoto, DDS, PhD, Yuichi Kimura, DDS, PhD, Xiaogu Wang, DDS, and Akinori Yamashita, DDS
The purpose of this study was to examine the histopathological response of dental pulp tissue to enamel matrix derivative (EMD) used as a pulp capping material. Thirty-two teeth from two mongrel dogs were divided into four equal groups. One group served as controls, and the others were used for deep Class V cavity preparation followed by direct pulp capping with enamel matrix derivative. The treated teeth were extracted after 1, 4, and 8 weeks and prepared for histopathological examination by light microscopy. All teeth prepared after 4 and 8 weeks demonstrated an increase in tertiary dentin, suggesting that enamel matrix derivative exerts a considerable influence on odontoblasts and endothelial cells of capillaries in dental pulp tissue. These results imply that enamel matrix derivative used as a pulp capping material may play a role in the calcification of dental pulp tissue.
Detection of Vascular Endothelial Growth Factor/Vascular Permeability Factor in Periapical Lesions
R. Leonardi, DDS, PhD, M. Caltabiano, DM, PhD, M. Pagano, DM, MS, V. Pezzuto, DM, C. Loreto, DM, and G. Palestro, DM, PhD
Vascular endothelial growth factor (VEGF), also known as vascular permeability factor (VPF), is a multifunctional cytokine. It is overexpressed in several conditions, which are characterized by vascular hyperpermeability and angiogenesis. In this investigation, we have evaluated the possibility that VEGF/VPF could be expressed in periapical lesions. We studied 17 periapical granulomas and 6 periapical cysts by immunohistochemistry. An immunopositive reaction for VEGF/ VPF was observed in all 23 periapical lesions; however, the intensity of immunostaining by anti-VEGF antibody varied according to histopathological findings. In periapical granulomas without epithelium, almost all of the inflammatory cells were immunoreactive to anti-VEGF/VIP antibody. In periapical granulomas, which had rests of Malassez in them, some inflammatory cells were stained. On the other hand, epithelial cells always were stained by VEGF/VPF antibody, both in periapical lesions with epithelium and in radicular cysts. This study demonstrated that periapical lesions express VEGF/VPF, although with some differences in cell immunolabeling, which correlated to the lesions’ stages on development. Initially, VEGF/VPF would assure angiogenesis and vascular hyperpermeability, resulting in accumulation of inflammatory cells, later it could be involved in cyst fluid accumulation. We hypothesize, therefore, that VEGF/VPF expression plays an important role in the pathogenesis of periapical granulomas and enlargement of radicular cysts by several mechanisms.
Human Periodontal Ligament Cell Viability in Milk and Milk Substitutes
Robert M. Pearson, DMD, Frederick R. Liewehr, DDS, MS, Leslie A. West, DDS, MS, William R. Patton, DDS, MS, James C. McPherson, III, PhD, and Royce R. Runner, BS
The purpose of this study was to determine the efficacy of several milk substitutes compared to whole milk in maintaining the viability of human periodontal ligament (PDL) cells on avulsed teeth. PDL cells were obtained from freshly extracted, healthy third molars and cultured in Eagle’s minimal essential media (EMEM). The cells were plated onto 24-well culture plates and allowed to attach for 24 h. EMEM was replaced with refrigerated whole milk (positive control), reconstituted powdered milk, evaporated milk, or one of two baby formulas (Similac® or Enfamil®). Tap water served as the negative control. Tissue culture plates were incubated with the experimental media at 37°C for 1, 2, 4, or 8 h. Cell viability was determined by a cell proliferation assay (CellTiter 96® AQ Assay), with absorbance read at 450 nM. A two-way ANOVA (p < 0.001) indicated that at 1 h there was no difference in the effect on PDL cell viability between any of the materials and whole milk. At 2 h, Enfamil® and Similac® performed significantly better than whole milk, whereas evaporated milk performed worse. At 4 h, Enfamil® performed better than whole milk, whereas all other milk substitutes performed worse. At 8 h, all substitutes performed worse than whole milk. These results suggest that Enfamil®, which is supplied in powder form that does not require special storage and has a shelf life of 18 months, is a more effective storage medium for avulsed teeth than pasteurized milk for at least 4 h.
In Vitro Antimicrobial Activity of Various Medication Preparations on E. faecalis in Root Canal Dentin
Richard E. Lynne, DDS, Frederick R. Liewehr, DDS, MS, Leslie A. West, DDS, MS, William R. Patton, DDS, MS, Thomas B. Buxton, PhD, and James C. McPherson, III, PhD
The purpose of this study was to evaluate the antimicrobial activity of several medication preparations in root canal dentin infected with Enterococus faecalis. Roots of extracted bovine incisors were prepared to standardized cylindrical test specimens, 5 mm in height. The smear layer was removed and the samples were autoclaved and then incubated at 37° C/5% CO2 for 24 h in brain-heart infusion (BHI) broth containing 7.0 x 104 colony forming units per ml of E. faecalis. The samples were washed in phosphate buffered saline and mounted to individual culture wells with sticky wax. Test medications were applied to fill the canal lumina; medication groups were: (a) sterile H2O (positive control); (b) a 10% mixture of 1.0 g Ca(OH)2 USP in 10 ml sterile H2O; (c) 10% Ca (OH)2 in 0.12% chlorhexidine gluconate (Peridex); (d) Peridex; and (e) uninoculated BHI (negative control). The samples were incubated at 37°C/5% CO2 for 24 h. Dentin samples for quantitative microbiology were then obtained with consecutive sterile burs (ISO 029, 035, 042). All three experimental groups demonstrated significantly greater antimicrobial activity than the positive control (p < 0.001). Group 2 demonstrated significantly greater antimicrobial activity than Group 3 or Group 4 at all dentin depths (p < 0.05). These results suggest that 10% Ca(OH)2 may be more effective than Peridex or 10% Ca(OH)2 in Peridex for the elimination of E. faecalis from dentin tubules.
Shearing Bond Strength of Endodontic Sealers to Gutta-percha
Michael Tagger, DMD, MS, Etty Tagger, DMD, Anthony H. L. Tjan, Dr Dent, DDS, and Leif K. Bakland, DDS
Strength of the bond of root canal sealers to gutta-percha seems to be an important property for maintaining the integrity of the apical seal. In the few studies published, different models and assessment methods were used. The purpose of our study was to adapt an effective and easily reproducible model and to test it on nine contemporary commercially available endodontic sealers. Gutta-percha disks with a diameter of 10 mm and thickness of 2 mm were prepared by warming gutta-percha cones and then fixed with plaster in 1-inch phenolic rings. Five-millimeter long sections of polyethylene tubing, filled with freshly mixed sealer, were placed on the gutta-percha and tested for shearing bond strength after setting. A custom made holder was attached to the rings and placed in an Instron machine, what was activated at a cross-arm speed of 0.5 mm per minute. The bond strength ranged from 0 MPa to 6.4 MPa. The sealers were ranked, and those that did not differ statistically in their bond strength were grouped together. This model provides a simple and reproducible means for measuring the in vitro bond strength of endodontic sealers.
An Immunohistological Study of the Localization of Bacterial Invading Root Pulpal Walls of Teeth with Periapical Lesions
Takashi Matsuo, DDS, PhD, Toshiyuki Shirakami, DDS, PhD, Kazumi Ozaki, DDS, PhD, Tadashi Nakanishi, DDS, PhD, Hiromichi Yumoto, DDS, PhD, and Shigeyuki Ebisu, DDS, PhD
We immunohistologically examined the prevalence and localization of bacteria invading dentinal tubules of the roots of teeth with infected canals. Forty extracted teeth with apical lesions were selected and divided into two groups: a group of untreated teeth and a group of canal-enlarged teeth. The bacteria in the specimens were detected by Brown-Brenn stain and the labeled-streptavidin-biotin method with specific antisera for 16-bacteria. Seventy percent of the examined teeth showed bacteria invading the dentinal tubules of the roots. Fusobacterium nucleatum, Eubacterium alactolyticum, E. nodatum, Lactobacillus casei, and Peptostreptococcus micros were abundant. Even in the canal-enlarged group, invasion of bacteria was observed in 65% of teeth. This study revealed the actual condition of bacteria in infected root dentin and suggested that the canal-enlargement procedure could not completely remove all the bacteria in the infected dentinal tubules of the root.
Proinflammatory Cytokines Induce Cyclooxygenase-2 mRNA and Protein Expression in Human Pulp Cell Cultures
Yu-Chao Chang, DDS, MMS, PhD, Shun-Fa Yang, Ms, Fu-Mei Huang, DDS, MMS, Chia-Ming Liu, DDS, Kuo-Wei Tai, DDS, MSD, and Yih-Shou Hsieh, PhD
The increase release of prostaglandins (PG) within pulpal tissues is considered to play a pathogenic role during pulpal disease progression. The rate-limiting step in the formation of PG from arachidonic acid is catalyzed by cyclooxygenase (COX). COX-2 is an inducible enzyme believed to be responsible for PG synthesis at site of inflammation. The effect of proinflammatory cytokines on human pulp cells with special reference to COX-2 expression has not been reported earlier. The aim of the present study was to investigate the effects of interleukin (IL)-1χ and tumor necrosis factor-χ (TNF-χ) on the expression of COX-2 mRNA gene and protein in cultured human pulp cells. Investigations of the time dependence of COX-2 mRNA expression in proinflammatory cytokines-treated human pulp cells revealed a rapid accumulation of the transcript, a significant signal first detectable 1 h after exposure. In addition, both IL-1χ and TNF- χ up-regulated COX-2 protein expression by human pulp cells. The kinetics of this response showed that COX-2 was detectable in cell lysates as early as 2 h post proinflammatory cytokines challenge and remained elevated throughout the 24-h incubation period. This suggests that one of the pathogenic mechanisms of pulpal inflammation in vivo may be the synthesis of COX-2 by resident cells in response to a proinflammatory cytokines challenge. COX-2 may play an important role in the regulation of prostanoid formation in the pathogenesis of pulpal inflammation. Taken together, we propose that the use of selective COX-2 inhibitors might provide a valuable tool in the control of pulpal inflammation.
Bilateral Oroantral Fistulas Following Devitalization Of Teeth By Arsenic Trioxide: A Case Report
Serhat Yalçin, DDS, PhD, Buket Aybar, DDS, PhD, Faruk Haznedaroğlu, DDS, PhD, and Emre Yǘcel, MD
Although it is well known that prolonged application or leakage of arsenic trioxide can cause severe damage to the periodontal tissues, the substance is still used by some dentists. This paper describes a case of arsenical necrosis of the jaws affecting the right and the left side of the maxilla. As a result of leakage into the tissues of an arsenical paste from the pulp chamber of endodontically treated teeth, bilateral oroantral fistula (OAF) occurred. It is concluded that there is no justification, whatsoever, for the use of arsenic in modern dental practice. In the following case, buccal advancement flap and submucosal palatal island flap techniques were used for to close the OAF. The submucosal palatal island flap technique resulted in successful closure of the OAF.
Apical Leakage of Four Endodontic Sealers
Ludovic Pommel, Imad About, David Pashley, and Jean Camps
The purpose of this study was to evaluate the sealing properties of four root canal sealers. Forty-eight maxillary central incisors were instrumented with Profile rotary instruments. They were randomly divided into four groups (n=12) and filled using lateral condensation with one of the four sealers: Sealapex, Pulp Canal Sealer, AH 26, and Ketac-Endo. The apical leakage was measured with a fluid filtration method and expressed as L sˉ1 KPaˉ1. The teeth filled with Sealapex displayed a higher apical leakage (8.42 + 4.2 10ˉ11 L sˉ1 KPa ˉ1) than those filled with AH 26 (2.10 + 1.39 10ˉ11 L sˉ1 KPaˉ1), Pulp Canal Sealer (0.17 + 0.09 10ˉ11 L sˉ1 KPa ˉ1) or Ketac-Endo (0.32 + 0.24 10ˉ11 L sˉ1 KPa ˉ1) (p < 0.01). No statistically significant difference was found among AH 26, Pulp Canal Sealer, and Ketac-Endo. No correlation was found between the sealing efficiency of the four sealers and their adhesive properties recorded in a previous study.
In Vitro Inhibitory Effect of EGTA on Macrophage Adhesion: Endodontic Implications
Juan J. Segura-Egea, DDS, MD, PhD, Alicia Jiménez-Rubio, DDS, MD, PhD, José V. Rios-Santos, DDS, MD, PhD, Eugenio Velasco-Ortega, DDS, MD, PhD, and Juan R. Clavo-Gutierrez, MD, PhD
Ethylene glycol-bis(β-aminoethyl ether)-N,N,N¹, N¹- tetraacetic acid (EGTA) is an specific calcium ion chelator proposed as endodontic irrigant. This study investigates the effect of EGTA on substrate adherence capacity of rat inflammatory macrophages. Inflammatory macrophages were obtained from Wistar rats and resuspended in RPMI-1640 medium. Sub-strate adherence capacity assays were carried out in Eppendorf tubes for 15 min of incubation at 37°C in a humidified atmosphere of 5% CO2. The adherence index was calculated. Results showed the EGTA decreased substrate adherence capacity of inflammatory macrophages in a time- and dose-dependent manner. The EGTA concentration that caused half-maximal inhibition (IC50) was 202 + 32 mM (p < 0.01). EDTA was more potent than EGTA in inhibiting macrophage adherence (IC50 = 185 + 22 mM). Calcium chloride (10 mM) decreased the EGTA inhibitory effect on adherence index by 60.2% (p < 0.01). We conclude that EGTA significantly decreased substrate adherence capacity of macrophages.
The Cemento-Dentino-Canal Junction, the Apical Foramen, and the Apical Constriction: Evaluation by Optical Microscopy
Elías Harrán Ponce, DDS, and José Antonio Vilar Fernández, BA, PhD
The cemento-dentino-canal junction, the apical construction, and the apical foramen are the principal reference points used to determine the apical limit for instrumentation and root canal filling. For a better understanding of these structures, the objective of this study was to evaluate histologically the localization of the cemento-dentino-canal junction and the diameters of the apical foramen and root canal at the cemento-dentino-canal junction. Eighteen anterior maxillary teeth (canines, central, and lateral incisors) were used, from which 269 histological sections were obtained and evaluated by optical microscopy. The results indicated that the longest extension of the cementum into the root canal was observed in the canines, this valued decreasing in the lateral incisors, and even more so in the central incisors. The widest diameter of the apical foramen corresponded to the lateral incisors, followed by the canines and the central incisors. The diameter of the root canal at the cemento-dentino-canal junction was greatest in the canines and lowest in the central and lateral incisors. Great variability was observed in the measurements of the extension of the cementum into the root canal AQ: 1