Ki-67 Expression in Dentigerous Cysts, Unicystic Ameloblastomas and Ameloblastomas arising form Dental Cysts
Piattelli, Lezzi, Fioroni, Santinelli, and Rubini
Coronal Microleakage of Five Materials Used to Create an Intracoronal Seal in Endodontically Treated Teeth
Galvan, West, Liewehr, and Pashley
Effect of Hydrogen Peroxide and Sodium Perborate on Biomechanical Properties of Human Dentin
Chng, Plamara, and Messer
Effectiveness of Intracanal Irrigants and Medications against the Yeast Candida albicans
Ferguson, Hatton, and Gillespie
Vascular Response of Current and Potential Dental Etchants
Çehreli, Onur, Taşman and Gümrükçüolu
Root Surface Temperature Increase during Er:YAG Laser Irradiation of Root Canals
Kimura, Yonaga, Yokoyama, Kinoshita, Ogata, and Matsumoto
The Effects of Eugenol and Epoxy-Resin on the Strength of a Hybrid Composite Resin
Cohen, Volovich, and Musikant, and Deutsch
Influence of the Canal Contents on the Electrical Assisted Determination of the Length of Root Canals
Pommer, Stamm, and Attin
Comparison of the Effectiveness of Bacteria Culture, 16S rDNA Directed Polymerase Chain Reaction, and Checkerboard DNA-DNA Hybridization for Detection of Fusobacterium nucleatum in Endodontic Infections
Moraes, Siqueira Jr., Colombo, das Neves Rôças, de Souza Ferreira, and Pilotto Domingues
Stimulation of Matrix Metalloproteinases by Black-Pigmented Bacteroides in Human Pulp and Periodontal Ligament Cell Cultures
Chang, Lai, Yang, Chan, and Hsieh
Effect of Calcium Hydroxide Dressing on Bacterial Endotoxin in Vivo
Silva, Nelson-Filho, Leonardo, Rossi, and Pansani
Influence of Calcium Hydroxide Dressing on the Obturation of Simulated Lateral Canals
Goldberg, Artaza and De Silvio
A Comparison of the Antimicrobial Efficacy of Three Calcium Hydroxide Formulations on Human Dentin Infected with Enterococcus faecalis
Sukawat and Srisuwan
Ki-67 Expression in Dentigerous Cysts, Unicystic Ameloblastomas and Ameloblastomas arising form Dental Cysts
Adriano Piattelli, MD, DDS, Giovanna Lezzi, DDS, Massimiliano Fioroni, DDS, Alfredo Santinelli, MD, and Corrado Rubini, MD
This study investigated whether or not an ameloblastoma developing in the wall of a dentigerous cyst is a distinct lesion from the unicystic ameloblastoma. An immunohistochemical evaluation of Ki-67 in dentigerous cysts, unicystic ameloblastomas, and ameloblastomas arising in dentigerous cysts was done. The values of Ki-67 positively were 3.14 for the dentigerous cyst, between 5.32 and 16.56 for unicystic ameloblastoma, and 11.77 for ameloblastoma arising in a dentigerous cyst. Statistically significant differences were found between the dentigerous cyst and the unicystic ameloblastoma and between the dentigerous cyst and the ameloblastoma arising from a dentigerous cyst. No statistically significant difference was present between unicystic ameloblastoma and ameloblastoma arising from dentigerous cyst. These immunohistochemical data confirm the hypothesis that an ameloblastoma arising from a dentigerous cyst has a similar biological behavior to the unicystic ameloblastoma and should be considered as merely a histologic variant.
Coronal Microleakage of Five Materials Used to Create an Intracoronal Seal in Endodontically Treated Teeth
Robert R. Galvan, Jr., DDS, Lesley A. West, DDS, MS, Fredrick R. Liewehr, DDS, MS, and David H. Pashley, DMD, PhD
The purpose of this study was to quantitatively compare the sealing effectiveness of five restorative materials that were used to create an intracoronal double seal. Fifty-two extracted mandibular molars were randomly divided into five groups of 10 teeth, and one positive and one negative control teeth. The crowns were removed and the pulpal floor and canal orifices were sealed with 3 mm of one of the following materials: Amalgabond, C&B Metabond, One-Step Dentin Adhesive with Æliteflo composite, One-Step with Palfique composite, or intermediate restorative material (IRM). Each tooth was affixed to a fluid filtration device and the seal was evaluated at 0, 1, 7, 30, and 90 days. The results showed a significant (p = 0.0001) difference in leakage between the materials. At 7 days, IRM, Æliteflo, and Palfique leaked significantly more than Amalgabond or C&B Metabond. Amalgabond consistently produced the best seal of all the materials throughout the duration of the study.
Effect of Hydrogen Peroxide and Sodium Perborate on Biomechanical Properties of Human Dentin
Hui Kheng Chng, BDS, MDSc, Joseph E. A. Palamara, PhD, and Harold H. Messer, MDSc, PhD
This study compared the ultimate tensile strength, micropunch shear strength, and microhardness of bleached and unbleached human dentin. Forty-four intact premolars were root canal treated and randomly divided into four groups. Bleaching agents were sealed in pulp chambers, as in clinical use. Group 1 (control) was treated with water, group 2 with 30% hydrogen peroxide, group 3 with sodium perborate mixed with water, and group 4 with sodium perborate mixed with 30% hydrogen peroxide. The teeth were stored in saline at 37°C for 7 days. The teeth were then section and biomechanical tests were carried out on dentin specimens that were obtained from all teeth. Intracoronal bleaching with 30% hydrogen peroxide and sodium perborate used either alone or in combination weakened dentin. Hydrogen peroxide alone tended to be more damaging than sodium perborate used alone or sodium perborate mixed with hydrogen peroxide.
Effectiveness of Intracanal Irrigants and Medications against the Yeast Candida albicans
J.W. Ferguson, DMD, MS, J. F. Hatton, and M. Jane Gillespie, MS, PhD
An in vitro study was conducted to determine the susceptibility of the yeast Candida albicans to various intracanal irrigants and medications. The minimum inhibitory concentration (MIC) of sodium hypochlorite, hydrogen peroxide, chlorhexidine digluconate, and aqueous calcium hydroxide that is required to kill a standardized inoculum of C. albicans was determined. Growth of the yeast was measured by optical density. Sodium hypochlorite, hydrogen peroxide, and chlorhexidine digluconate were effective anticandidal agents with MICs of <10 μg/ml, 234 μg/ml, and < 0.63 μg/ml, respectively. Aqueous calcium hydroxide had no activity. A standardized inoculum of C. albicans cells was also placed in direct contact with either calcium hydroxide paste or camphorated para-monochlorophenol (CPMC), and candidal growth was assessed by colony counts on Sabouraud’s dextrose agar. Calcium hydroxide paste and CMPC, when maintained in direct contact with C. albicans, were effective antifungal agents.
Vascular Response of Current and Potential Dental Etchants
Zafer C. Çehreli, DDS, PhD, Mehmet Ali Onur, PhD, Fügen Taşman, DDS, PhD, and Ayşe Gümrükçüolu, BSc
This study investigated the hemostatic properties of current and potential dentin conditioners by observing the contraction of blood vessels using the rat carotid artery model. Four different agents (3M Scotchbond etchant, NRC, RC-Prep, File-Eze) were used. Dose-dependent contractions/relaxations of the test materials were first compared with epinephrine, followed by administration of papaverine, which was used to reverse epinephrine-induced contractions. In all sequences, the contraction or relaxation forces produced by the test and control materials were recorded using a force displacement transducer. RC-Prep was the only agent to produce epinephrine-like contractions (vasoconstriction) in the rat carotid artery. No contraction could be achieved with 3M etchant. Dose-dependent relaxations were observed with 3M etchant, which eventually led to collapse of the vessel wall; afterward, no response could be achieved with administration of adrenalin. File-Eze and NRC also did not cause vasoconstriction. Both materials caused dose-dependent relaxations in the smooth muscle. However, subsequent administration of adrenalin and papaverine caused dose-dependent contractions and relaxations, respectively, showing that these etchant effects did not lead to collapse of the vessel wall, as did 3M etchant.
Root Surface Temperature Increase during Er:YAG Laser Irradiation of Root Canals
Yuichi Kimura, DDS, PhD, Kazuo Yonaga, DDS, PhD, Keiko Yokoyama, DDS, PhD, Jun-ichiro Kinoshita, DDS, Yoshiko Ogata, DDS, and Koukichi Matsumoto, DDS, PhD
The authors measured the temperature of the root surface during the root canal preparation using Er:YAG laser irradiation and evaluated the thermal effect on the periodontal region. Twenty extracted human teeth with single roots were divided into two groups of 10. These were irradiated using an Er:YAG laser at 2 Hz and 136 to 184 or 170 to 230 mJ/pulse for 1 min with a water spray. The temperature of the root surface was monitored using thermocouples throughout the procedure. The teeth were longitudinally bisected and observed by stereoscopy and scanning electron microscopy. The temperature on the root surface increased by less than 6°C at the apical area and by less than 3°C at the central area. A morphological evaluation revealed that no carbonization or melting. These results suggest the thermal effect on periodontal tissues during root canal preparation using an Er:YAG laser at less than 230 mJ/pulse for 1 min is minimal.
The Effects of Eugenol and Epoxy-Resin on the Strength of a Hybrid Composite Resin
Brett I. Cohen, PhD, Yekaterina Volovich, BS, Barry Lee Musikant, DMD, and Allan S. Deutsch, DMD
The compatibility of different dental materials (root canal sealer and composite core build-up restoratives) is an important factor for a successful restoration. The aim of this in vitro study was to determine the effects on compressive and diametral tensile strength of a classical chemical cure composite resin (Henry Schein Composite Anterior Posterior dental restorative) when in contact with either eugenol or an epoxy-resin (EZ-Fill) in a variety of situations: (a) eugenol or epoxy-resin added during mixing of a composite resin before curing; (b) vapor exposure to cured samples; and (c) specimens placed directly in eugenol or epoxy-resin (after curing). Compressive strengths and diametral tensile strengths were tested for each group. Only the addition of eugenol during mixing with the composite resin (directly before curing) resulted in specimens that were unable to be tested, because they did not achieve a full cure or hardness. For all other groups, there were no significant differences with respect to either compressive strength (p = 0.17) or diametral tensile strength (p = 0.39). Group 1 (mixed directly with eugenol) was found to be statistically different from groups 2 through 7.
Influence of the Canal Contents on the Electrical Assisted Determination of the Length of Root Canals
Oliver Pommer, Oliver Stamm, and Thomas Attin
The purpose of this study was to compare the influence of the root canal status on the determination of the root canal length by an electronic apex locator in vital and necrotic canals and canals with root canal filling retrieval. One hundred seven teeth with a total of 171 canals with various contents (105 vital pulp, 47 necrotic pulp, and 19 retrieval of root canal filling materials) were measured for root canal length in vivo with the AFA Apex Finder. The distance between the file tip and the radiographic apex was also determined on radiographs. In 86% of the evaluated roots, the file tip position as indicated by the Apex Finder was located within 0.5 mm of a point 1.0-mm short of the radiographic apex. The Apex Finder showed higher accuracy for determining the apical constriction in vital canals (93.9%) than in necrotic canals (76.6%), and this difference was statistically significant (p ≤ 0.05). The Apex Finder indicated the point -1 mm ± 0.5 mm in canals with retrieval of root canal filling materials in 68.4% of these cases, but because of the small number of retrieval cases, this is not comparable statistically with vital and necrotic cases. The authors concluded that the AFA Apex Finder is highly accurate in vital canals.
Comparison of the Effectiveness of Bacteria Culture, 16S rDNA Directed Polymerase Chain Reaction, and Checkerboard DNA-DNA Hybridization for Detection of Fusobacterium nucleatum in Endodontic Infections
Saulo Roni Moraes, MsC, José Freitas Siqueira Jr., PhD, Ana Paula Colombo, PhD, Isabela das Neves Rôças, DDS, Maria Candida de Souza Ferreira, PhD, and Regina Maria Cavalcanti Pilotto Domingues, PhD
Fusobacterium nucleatum is a Gram-negative, non-spore-forming, nonmotile, obligatory anaerobic rod that is normally isolated from the oral cavity. Epidemiological studies have shown that this species is one of the most prevalent in primary root canal infections. The purpose of this study was to compare the effectiveness of bacteriological culture, 16S rDNA directed polymerase chain reaction and checkerboard DNA-DNA hybridization for detection of F. nucleatum strains in infected teeth associated with periradicular lesions. Thirteen single-root teeth from adult patients, all having carious lesions, necrotic pulps, and radiographic evidence of periradicular bone loss were included in this study. Combining all methods, the results indicated that F. nucleatum was present in approximately 31% (4 of 13) of the specimens. Incidence of F. nucleatum in root canal infections, as evaluated in this study by polymerase chain reaction, culture, and DNA-DNA hybridization, was 15.4%, 15.4%, and 10.0%, respectively. Our data demonstrated that no method used herein could be considered superior for detecting F. nucleatum directly from clinical samples. However, the small number of samples examined and the low prevalence that was observed should be considered.
Stimulation of Matrix Metalloproteinases by Black-Pigmented Bacteroides in Human Pulp and Periodontal Ligament Cell Cultures
Yu-Chao Chang, DDS, MMS, Chung-Chi Lai, DDS, Shun-Fa Yang, BS, You Chan, DDS, PhD, and Yih-Shou Hsieh, PhD
Matrix metalloproteinases (MMPs) are a group of proteolytic enzymes capable of degrading most components of the extracellular matrix. Recently, evidence has shown that MMPs may play a role in tissue degradation in inflamed dental pulp. To date very little is known regarding the mechanism of extracellular matrix destruction at the site of bacterial infection. The purpose of this study was to determine the effects of the supernatants from Porphyromonas endodontalis and Porphyromonas gingivalis on the production and secretion of gingivalis on the production and secretion of MMPs by primary human pulp and periodontal ligament (PDL) cell cultures in vitro. The results were evaluated by substrate gel zymography from long-term cultures. The main gelatinase secreted by human pulp and PDL cells migrated at 72 kDa and represented MMP-2. Minor gelatinolytic bands were also observed at 92 kDa regions that correspond to MMP-9. After an 8-day culture period, P. endodontalis and P. gingivalis were found to elevate MMP-2 production both in human pulp and PDL cell cultures. In addition, the stimulation was in a dose- and time-dependent manner. Both human pulp and PDL cells, however, treated with either P. endodontalis or P. gingivalis had no effect on the pattern of MMP-9 produced or secreted in either cell extracts or conditioned medium fractions. These results indicate that black-pigmented Bacteroides species play an important role in tissue destruction and disintegration of extracellular matrix in pulpal and periapical diseases. Thus, activation of MMPs may be one of the distinct host degradative pathways in the pathogenesis of microbial-induced pulpal and periapical lesion. An understanding of the actions of these black-pigmented Bacteroides species on pulp and PDL cells may result in new therapies to augment current treatment of pulpal and periapical lesions.
Effect of Calcium Hydroxide on Bacterial Endotoxin In Vivo
Léa Assed Bezerra Silva, DDS, PhD, Paulo Nelson-Filho, DDS, PhD, Mário Roberto Leonardo, DDS, PhD, Marcos A. Rossi, MD, PhD, and Cyneu Aguiar Pansani, DDS, PhD
The aim of this study was the histopathological evaluation of apical and periapical tissues in dog teeth that were submitted to bacterial endodotoxin, associated or not with calcium hydroxide. After removal of the pulp from 60 premolars, the teeth were divided into four groups and were filled with bacterial endodotoxin (group 1), bacterial endodotoxin plus calcium hydroxide (group 2), saline solution (group 3), or had induced periapical lesions with no treatment (group 4). After 30 days, animals were killed and the teeth processed histologically. The inflammatory infiltrate, the thickness of the periodontal ligament, and the presence of resorption areas were similar for groups 1 and 4. Groups 2 and 3 were similar to each other. It can be concluded that the bacterial endotoxin caused a periapical lesion and that calcium hydroxide detoxified the lipopolysaccharides in vivo.
Influence of Calcium Hydroxide Dressing on the Obturation of Simulated Lateral Canals
Fernando Goldberg, DDS, Liliana P. Artaza, DDS, and Ana C. De Silvio, DDS
The purpose of this in vitro study was to evaluate what influence an interappointment dressing with calcium hydroxide might have on the ability to subsequently obturate simulated lateral canals. Twenty extracted single-rooted human teeth were instrumented at the working length to a #35 file before creating three simulated lateral canals on the mesial and distal surfaces of the root, one in each third, using a #15 engine reamer. After enlarging the root canals to a #45 file, the teeth were randomly divided into two groups of 10. In both groups AH26 was used as the sealer. In the group A, the obturation was performed immediately using Ultrafil. In group B, root canals were filled with calcium hydroxide and incubated for 7 days. The teeth were then reinstrumented, irrigated with 2.5% sodium hypochlorite solution, dried with paper points, and obturated as in group A. Teeth in group A showed a larger number of filled lateral canals compared with those in group B. Statistical significant differences were observed when comparing the same third in the two groups (apical third p < 0.05, middle third p < 0.01, and coronal third p < 0.01). No differences were found among the different thirds in the same group (p > 0.05).
A Comparison of the Antimicrobial Efficacy of Three Calcium Hydroxide Formulations on Human Dentin Infected with Enterococcus faecalis
Chongkiat Sukawat, DDS, and Thanapen Srisuwan, DDS, MS
This study compared the antimicrobial efficacy of three different formulations of calcium hydroxide by using human dentin specimens that were infected with Enterococcus faecalis. After exposure to three forms of calcium hydroxide (calcium hydroxide mixed with distilled water, calcium hydroxide mixed with distilled water, calcium hydroxide mixed with 0.2% chlorhexidine, and calcium hydroxide mixed with camphorated paramono-chlorophenol) for 7 days, dentin powder from the infected specimens was obtained and assessed for bacterial quantity by spectrophotometry. It was found that calcium hydroxide mixed with camphorated paramono-chlorophenol killed all the Enterococcus faecalis inside the dentinal tubules. The result was better than that obtained with calcium hydroxide mixed with distilled water or with 0.2% chlorhexidine (p < 0.05). Calcium hydroxide mixed with distilled water and calcium hydroxide mixed with 0.2% chlorhexidine were ineffective against these bacteria.