CD1a-Positive Cells in Odontogenic Cysts
Piattelli, Rubini, Lezzi, Fioroni
Microbial Leakage Evaluation of the Continuous Wave of Condensation
Jacobson, Xia, Baumgartner, Marshall, and Beeler
Evaluation of Leakage of Bacteria and Endotoxins in Teeth Treated Endodontically by Two Different Techniques
Carratù, Amato, Riccitiello, and Rengo
Bacteriologic Evaluation of the Effect of Nd:YAG Laser Irradiation in Experimental Infected Root Canals
Piccolomini, D’Arcangelo, D’Ercole, Catamo, Schiaffino, and De Fazio
An Optimal Host Response to a Bacterium May Require the Interaction of Leukocytes and Resident Host Cells
Jiang and Schilder
Canal-Centering Ability of Two Rotary File Systems
Ponti, McDonald, Kuttler, Strassler, and Dumsha
Effect of Methotrexate-Induced Neutropenia on Pulpal Inflammation in Rats
Nakamura, Yamasaki, Nishigaki, Iwama, Imaizumi, Nakamura, and Kameyama
Resinous Perforation-Repair Materials Inhibit the Growth, Attachment, and Proliferation of Human Gingival Fibroblasts
Huang, Tai, Chou, and Chang
Effect of Irrigating Solution and Calcium Hydroxide Root Canal Dressing on the Repair of Apical and Periapical Tissues of Teeth with Periapical Lesion
Filho, Leonardo, and Bezerra da Silva
Evaluation of Glyde File prep in Combination with Sodium Hypochlorite as a Root Canal Irrigant
Grandini, Balleri, and Ferrari
Microbiota of Periapical Lesions Refractory to Endodontic Therapy
Sunde, Olsen, Debelian, and Tronstad
The Effect of Instrumentation with Two Different File Types, Each with 2.5% NaOCl Irrigation on the Microhardness of Root Dentin
Slutzky-Goldberg, Liberman, and Heling
Tissue Levels of Matrix Metalloproteinases I Pulps and Periapical Lesions
Shin, Lee, Baek, and Lim
A Comparison of Shaping Ability Using ProFile, GT File, and Flex-R Endodontic Instruments in Simulated Canals
Hata, Uemura, Kato, Imura, Novo, and Toda
Hemostatic Efficacy and Cardiovascular Effects of Agents Used During Endodontic Surgery
Vickers, Baumgartner, and Marshall
CD1a-Positive Cells in Odontogenic Cysts
Adriano Piattelli, MD, DDS, Corrado Rubini, MD, Giovanna Lezzi, DDS, and Massimiliano Fioroni, DDS
Langerhans cells (LC) are bone marrow –derived cells that have a CD1a-positive immunophenotype and are an important portion of the cell-mediated immune response. The aim of this study was an immunohistochemical evaluation of CD1a positive cells in different types of oral cysts. Fifty-five cysts were studied: 18 odontogenic keratocysts (OKC), of which five were orthokeratocysts and 13 parakeratotic; 19 radicular cysts. Positive LC was 80% for orthokeratotic OKC, 33% for parakeratotic OKC, approximately 35% for radicular cyst, and approximately 20% for dentigerous cysts. The results show that OKC with well-differentiated epithelial linings presented a greater number of LC than the other cysts. However, when the cyst wall was inflamed there were no difference in LC expression in the differences in LC expression in the different types of cysts. The data confirm that LC distribution seems to be associated with the degree of differentiation of the epithelia.
Microbial Leakage Evaluation of the Continuous Wave of Condensation
H. L. Jay Jacobson, DDS, Tian Xia, DDS, PhD, J. Gordon Marshall, DMD, and William J. Beeler, DMD, MS
Coronal leakage has been recognized as a cause of pulpal and periradicular disease. Although cleaning and shaping of the root canal system is considered paramount, obturation of the system is an important step in endodontic success. The purpose of this study was to evaluate coronal bacterial leakage in teeth obturated within the System B continuous wave of condensation technique, followed by an Obtura II backfill, versus teeth obturated using the lateral condensation technique. Sixty single-rooted bilaterally matched teeth were evaluated in this study. An anaerobic bacterial leakage model was used. Results indicate that microbial coronal leakage occurs more quickly using lateral condensation than with the System B continuous wave of condensation and Obtura II backfill. This difference was statistically significant (p ≤ 0.05). However, there was no statistical difference between group 1 and 2 in the numbers of teeth that demonstrated bacterial leakage at the end of the study.
Evaluation of Leakage of Bacteria and Endotoxins in Teeth Treated Endodontically by Two Different Techniques
P. Carratù, DDS, M. Amato, MD, F. Riccitiello, MD, and S. Rengo, MD
Root canal recontamination occurs after contact between oral-bacterial flora and the coronal extremity of the root canal. The aim of this study was to evaluate the time required for endotoxins and bacteria to penetrate through root-canal obturations performed with vertical and lateral gutta-percha condensation techniques. Specimens prepared by the two alterantive methods were exposed to contaminated saliva, and leakage into the root was evaluated over time. None of the obturated roots was infiltrated by endotoxins after 31 days. On the contrary, between day 13 and day 37 bacteria had infiltrated all specimens.
Bacteriaologic Evaluation of the Effect of Nd:YAG Laser Irradiation in Experimental Infected Root Canals
Raffaele Picolomini, MD, Camillo D’Arcangelo, DDS, Simonetta D’Ercole, DDS, Giovanni Catamo, LT, Gianluigi Schiaffino, MD, and Pietro De Fazio, MD, DDS
The aim of this study was to evaluate the efficacy of the Pumped Diodium-Nd:YAG laser in sterilizing contaminated root canals. After hand instrumentation, 30 teeth were inoculated with Actinomyces naeslundii CH-12 and 30 teeth with Pseudomonas aeruginosa ATCC 27853 and incubated for 24 h. The teeth were divided into three subgroups: subgroup A received no treatment; subgroup B was irradiated with laser (5 Hz for 15 s or 10 Hz for 15 s); and subgroup C was irrigated with 5.25% NaOCl. The number of viable bacteria in each group was evaluated by using the surface-spread plate technique. The results indicated an average of 34.0% decrease in colony-forming units for A. naeslundii CH-12 and 15.7% for P. aeruginosa ATCC 27853 with the 5 Hz/15 s laser treatment, and for the 10 Hz laser frequency, a decrease of the 77.4% for A. naeslundii CH-12 and 85.8% for P. aeruginosa ATCC 27853. No bacteria were detected in the canals treated with 5.25% NaOCl. The results show an antibacterial effect of the Pumped Diodumä Nd:YAG laser, depending on the radiation frequency. However, 5.25% NaOCl was more effective than either laser application.
An Optimal Host Response to a Bacterium May Require the Interaction of Leukocytes and Resident Host Cells
Yanling Jiang, DMD, DSc, and Herbert Schilder, DDS
Bacterial infection results in inflammatory responses that may lead to soft-tissue damage and bone resorption. However, the mechanisms by which different bacteria contribute to lesions of endodontic origin are not fully understood. This study examined the response to Streptococcus mutans and Porphyromonas endodontalis in two cell types that are involved in periapical pathology, mononuclear and osteoblastic cells. This was accomplished by measuring the induction of chemokines (monocyte chemoattractant protein-2) and proinflammatory cytokines (interleukin-1β, tumor mecrosis factor-α, interleukin-6, interferon-γ). The results demonstrated that S. mutans more efficiently stimulate inflammatory cytokine production by mononuclear cells, where as P. endodontialis is relaticely more potent in activating osteoblastic cells. Moreover, optimal activation of osteoblastic cells by S. mutans requires soluble mediators produced by mononuclear cells, whereas P. endodontalis does not. Theses results suggest that the association of different bacteria with specific pathologic processes may be partially explained by their capacities to activate specific host cells.
Canal-Centering Ability of Two Rotary File Systems
Tony M. Ponti, DDS, MSD, N. J. McDonald, BSc, BDS, MS, Sergio Kuttler, Howard E. Strassler, and Thomas C. Dumsha, MS, DDS, MS
The ability of two nickel-titanium rotary file systems to maintain the original path of the canal were compared by using a new split-mold design (the Endodontic Cube). The mesial roots of 10 mandibular first- and second-molar teeth with separate canals from orifice to foramen were divided into two groups based on canal curvature and morphology. Working lengths for each canal were determined 1.0 mm short of where the file tip was visible on the external surface of the root. The teeth wre embedded in composite resin by suing the Endodontic Cube as a mold and sectioned into five pieces. ProFile Ni-Ti .06 taper Series 29 and Profile GT rotary instrumentation techniques were randomly assigned to on eof the canals and used in a crown-down fashion to a 0.217 ProFile and a 0.06 GT master apical file, respectively. Digital photographs were made of the middle three sections and the software features of Adobe Photoshop were used to measure the movement of the canal centers by superimposing the images of the instrumented and uninstrumented canals. Data were analyzed using ANOVA. Both systems remained centered within the canal with minimal deviation from the original canal path. The largest mean movement was less than 0.15 mm. The Endodontic Cube was an effective tool for studying and comparing instrumentation techniques.
Effect of Methotrexate-Induced Neutropenia on Pulpal Inflammation in Rats
Koki Nakamura, DDS, PhD, Masahiro Yamasaki, DDS, PhD, Noriyuki Nishigaki, DDS, Akihiro Iwama, DDS, PhD, Ichro Imaizumi, DDS, PhD, Hiroshi Nakamura, DDS, PhD, and Yoichiro Kameyama, DDS, PhD
The purpose of this study was to determine the role of neutropenia in pulpal inflammation. We investiged the effect of methotrexate-induced neutropenia on pulpal inflammation in rats. Pulpal inflammation was produced by pulpal exposure. Thirty-six rats were divided equally into control and experimental groups. The control animals received no injection, whereas the experimental animals were injected with 7.5 mg/kg of methotrexate once a day for 3 days before the pulpal exposure. The pulp was exposed in the mandibular first molar of all animals, and the exposed areas where left open. Animals were killed at 2, 4, and 7 days thereafter. Before they were killed, peripheral blood was taken. The number of total leukocytes and neutorphils in the peripheral blood of experimental animals was significantly decreased compared with those of control animals was significantly decreased compared with those of control animals. The methotrexate-induced neutropenia resulted in the initiation of a bacterial invasion into the pulpal tissue and an increase in pulpal necrosis, as well as lessened abscess formation. Histometrically, the area of pulpal necrosis in experimental animals was significantly greater than that in the control animals. Immunohistochemically, the neutropenia resulted in inhibition of the infiltration by neutrophils. These results suggest that the neutrophil plays an important role in the defense against bacteria in pulpal tissue.
Resinous Perforation-Repair Materials Inhibit the Growth, Attachment, and Proliferation of Human Gingival Fibroblasts
Fu-Mei Huang, DDS, MMS, Kuo-Wei Tai, DDS, MSD, Ming-You Chou, DDS, PhD, and Yu-Chang, DDS, MMS
The choice of repair material is one of the important factors in the prognosis of the endodontically treated tooth with a perforation defect. The cytotoxicity of perforation-repair materials must be investigated to ensure a safe biological response. The aim of this in vitro study was to evaluate the effect o fresin-modified, glass-ionomer cement, compomer, and resin on human-gingival fibro-blasts. Human gingival fibroblasts from crown lengthening surgery were cultured by using an assay of tetrazolium bromide reduction. The results showed that resin-modified, glass-ionomer cement Fuji II LC, compomer Compoglass, and resin SpectrumTPH (TPH) were Cytotoxic to primary human gingival fibroblast culturesby inhibiting cell growth and proliferation. TPH alone had an effect on cell attachment. It was found that TPH was the most Cytotoxic repair material among those tested in all cultures. The toxicity decreased in the order of TPH>FLC>CG.
Effect of Irrigating Solution and Calcium Hydroxide Root Canal Dressing on the Repair of Apical and Periapical Tissues of Teeth with Periapical Lesion
Mário Tanomaru Filho, DDS, PhD, Mario Roberto Leonardo, DDS, PhD, and Léa Assed Bezerra da Silva, DDS, PhD
The objective of this study was to evaluate the apical and periapical repair after endodontic treatment of teeth with pulp necrosis and a chronic periapical lesion in dogs. Seventy-two root canals form four mongrel dogs were submitted to biomechanical preparation, using 5.25% sodium hypochlorite or 2% chlorhexidine digluconate as the irrigating solution. The root canals were subsequently either filled immediately with Sealapex, using active lateral gutta-percha condensation, or a calcium hydroxide root canal dressing was applied for 15 days before filling with Sealapex. After 210 days, the animals wee killed by anesthetic overdose, and the obtained histological sections were stained with hematoxylin and eosin for optical microscopic analysis of apical and periapical repair. There was better histological repair in the group with the root canal dressing (p < 0.05) than the group with immediate obturation. Comparing the immediate obturation groups, irrigation with chlorhexidine solution resulted in better repair than sodium hypochlorite.
Evaluation of Glyde File prep in Combination with Sodium Hypochlorite as a Root Canal Irrigant
Simone Grandini, DDS, Piero Balleri, MD, DDS, and Marco Ferrari, MD, DDS, PhD
The purpose of this study using a scanning electron microscope was to investigate the efficacy of four different irrigation techniques after canal preparation with Profile Ni-Ti rotary instruments. A modified technique for the use of Glyde File Prep is proposed. Forty anterior teeth were divided into four groups, instrumented, and irrigated as follows: physiological solution (group A), 2.5% sodium hypochlorite and Glyde File Prep applied at he end of the preparation with sterile paper points (group D). After scanning electron microscopic evaluation at three different levels, debris, smear layer, and dentinal tubules were scored. Groups A and B had significantly more smear layer and less open tubules on the canal walls compared with the group C and group D samples. Differences in the mean amount of debris between group A samples and other irrigation regimes were statistically significant.
Microbiota of Periapical Lesions Refractory to Endodontic Therapy
Pia Titterrud Sunde, DDS, Ingar Olsen, DDS, PhD, Gilberto J. Debelian, DDS, PhD and Leif Tronstad, DMD MS, PhD
The periapical microbiota of 36 teeth with refractory apical periodontitis was investigated. None of the teeth had responded to conventional endodontic or long-term (> 6 months), calcium-hydroxide treatment. Eight patients had received antibiotics systemically. After anaerobic culture, a total of 148 microbial strains were detected among 67 microbial species. One of the 36 lesions was culture-negative. Approximately half (51.0%) of the bacterial strains were anaerobic. Gram-positive species constituted 79.5% of the flora. Facultative organisms, such as Staphylococcus, Enterobacter, Pseudomonas, Stenotrophomonas, Sphingomonas, Bacillus, or Candida species were recovered from 27 of the slesions (75%). Sulfur granules were found in 9 lesions (25%). In theses granules Actinomyces isreallii, A. meyeri were identified. Other bacterial species, both Gram-positive and Gram-negative, were detected in the granules as well. Two sulfur granules did not contain Actinomyces. Scanning electron microscopy demonstrated rod and spirochete-like cells in the granule, and transmission electron microscopy revealed organisms with copious amounts of extracellular material. Outer membrane vesicles were also seen. Some of the granules were calcified. This study demonstrated a wide variety of microorganisms, particularly Gram-positive ones, in the periapical lesions of teeth with refractory apical periodontitis.
The Effect of Instrumentation with Two Different File Types, Each with 2.5% NaOCl Irrigation on the Microhardness of Root Dentin
Iris Slutzky-Goldberg, DMD, Reuven Liberman, DMD and Illana Heling DMD, MSc
The aim of this study was to measure root-dentin microhardness after instrumentation with two types of files and using irrigation with 2.5% sodium hypochlorite. Thirty roots were instrumented with irrigation: 10 roots had the pulp extirpated only; 10 roots were instrumented with rotary nickel-titanium (NiTi) files. Additionally, five roots were extirpated only without irrigation and served as a control. The roots were sliced and root-dentin microhardness was determined at depths of 500 μm and 1000 μm from the pulp-dentin interface. Significant differences were found between the microhardness at 500 μm and 1000 μm (p < 0.001) in all groups. Instrumentation with NiTi rotary files affected dentin microhardness significantly to a lesser extent.
Tissue Lebels of Matrix Metalloproteinases I Pulps and Periapical Lesions
Su-Jung Shin, DDS, Jae-II Lee, DDS, MSD, PhD, Seung-Ho Baek, DDS, MSD, PhD and Sung-Sam Lim, DDS, MSD, PhD
The purpose of this study was to evaluate the tissue levels of matrix metalloproteinase (MMP)-1, -2, -3 and their distributions in inflamed human dental pulps and periapical lesions. Samples were subjected to enzyme-linked immunosorbent assay were analyzed by using the Mann-Whitney U test and presented as p values. The concentrations of MMP-1 in all experimental groups were significantly higher than in the control groups were significantly higher than in the control groups (p < 0.05). The acute pulpitis and control groups were significant different in terms of their MMP-2 levels (p< 0.05). The concentration f MMP-3 in acute pulpitis was significantly higher that the control and chronic pulpitis groups (0.05). Immunohistochemically, MMP-1 and MMP-3 were localized in the filtrating neutrophils, macrophages, and extracellular matrix of the acute pulpitis group.
These results suggest that MMPs play an important role in the pulp tissue destruction of acute, inflamed pulp.
A Comparison of Shaping Ability Using ProFile, GT File, and Flex-R Endodontic Instruments in Simulated Canals
Gin-ichiro Hata, DDS PhD, Manabu Uemura, DDS, PhD, Augusto S. Kato, DDS, Noboru Imura, DDS, Niel F. Novo, and Tadao Toda, DDS, PhD
A total of 160 resin-simulated canal blocks with 20-degree or 30-degree curvature were prepared by ProFile rotary instruments, GT rotary files, and the balanced force technique with Flex-R files. Using an image analysis computer application, the pre-and postoperative images were stored and superimposed, and then the amount of material removed form the preoperative inner and other curved walls was measured at five levels in the apical 5 mm of the canal. The time required for canal preparation including irrigation, and the time taken to change instruments was recorded. At 1 mm from the apical end, the directions of the canal transportation were most frequently toward the outer aspect of the curvature, with the only exception being the canals shaped by the balanced force technique in which more was removed from the inner aspect. The balance force technique required more preparation time than the rotary instrumentation.
Hemostatic Efficacy and Cardiovascular Effects of Agents Used During Endodontic Surgery
Francine J. Vickers, DDS, J. Craig Baumgartner, DDS, PhD, and Gordon Marshall, DMD
The hemostatic efficacy, as well as the cardiovascular effects, of two hemostatic agents currently used during endodontic surgery was examined. The hemostatic static agents used were epinephrine pellets (Racellet pellets) or 20% ferric sulfate (Viscostat). Patients were assigned to one of two experimental groups. Blood pressure and pulse rate were recorded pre- and postoperatively and at three additional times during the surgery (root-end resection, root-end preparation, and filling). The adequacy of hemostasis was rated by the surgical operator. Results indicated that there is no significant change in cardiovascular effects when using either of these hemostatic agents. Except in one case where ferric sulfate was the agent, both agents produced surgical hemostasis that allowed for a dry field for root-end filling.