Herpesviral-bacterial Coinfection in Periapical Pathosis
Mohammad Sabeti, and Jørgen Slots
Radiographic Evaluation of Root Canal Multiplicity in Mandibular First Premolars
Takatomo Yoshioka, Juan C. Villegas, Chihiro Kobayashi, and Hideaki Suda
Relationship of Radiologic and Histologic Signs of Inflammation in Human Root-filled Teeth
Claudia R. Barthel, Stefan Zimmer, and Martin Trope
Repair of Root Perforations Using Mineral Trioxide Aggregate: A Long-term Study
Craig Main, Nina Mirzayan, Shahrokh Shabahang, and Mahmoud Torabinejad
Antibacterial Activity of 2% Chlorhexidine Gluconate and 5.25% Sodium Hypochlorite in Infected Root Canal: In Vivo Study
Ertugrul Ercan, Tuncer Özekinci, Fatma Atakul, and Kadri Gül
Proinflammatory Cytokine Profiles in Pulp Fibroblasts Stimulated with Lipopolysaccharide and Methyl Mercaptan
Jeffrey Coil, Esther Tam, and J. Douglas Waterfield
Effectiveness of Sodium Hypochlorite in Preventing Inoculation of Periapical Tissues With Contaminated Patency Files
K. H. Izu, S. J. Thomas, P. Zhang, A. E. Izu, and S. Michalek
Reactions of Connective Tissue to Mineral Trioxide Aggregate and Amalgam
Mehmet Yaltirik, Hakan Ozbas, Bilge Bilgic, and Halim Issever
The Influence of the Smear Layer on Dentinal Tubule Penetration Depth by Three Different Root Canal Sealers: An In Vitro Study
Andreas B. Kokkas, Asterios Ch. Boutsioukis, Leonidas P. Vassiliadis, and Christos K. Stavrianos
A Comparison of Laterally Condensed Gutta-Percha, Thermoplasticized Gutta-Percha, and Mineral Trioxide Aggregate as Root Canal Filling Materials
Paul J. Vizgirda, Frederick R. Liewehr, William R. Patton, James C. McPherson, and T. B. Buxton
Comparison Instrumentation Time of Conventional Reamers and Files versus a New, Noninterrupted, Flat-sided Design
Barry Lee Musikant, Brett I. Cohen, and Allan S. Deutsch
Influence of Instrument Size on Root Canal Debridement
Najia Usman, J. Craig Baumgartner, and J. Gordon Marshall
Effect of Medications for Root Canal Treatment on Bonding to Root Canal Dentin
Ali Erdemir, Hale Ari, Hakan Güngünes, and Sema Belli
Mental Nerve Paresthesia Associated with an Adhesive Resin Restoration: A Case Report
Osvaldo Zmener
MTA for Obturation of Mandibular Central Incisors with Open Apices: Case Report
Mikako Hayashi, Ayako Shimizu, and Shigeyuki Ebisu
Herpesviral-bacterial Coinfection in Periapical Pathosis
Mohammad Sabeti, DDS, MA and Jørgen Slots, DMD, DDS, PhD, MS, MBA
Two members of the herpesvirus family, human cytomegalovirus (HCMV) and Epstein-Barr virus (EBV), seem to be important putative pathogens of human periodontitis and symptomatic periapical lesions, causing pathosis either by inducing immunosuppression with a subsequent risk of aggressive bacterial infections or by infecting of periodontal cells directly. This study aimed to relate periapical occurrence of HCMV, EBV, and herpes simplex virus active infections to clinical characteristics of periapical lesions and periapical bacterial flora. Microbial samples were collected from 34 periapical lesions in conjunction with periapical surgery. Part of the periapical specimen was frozen for virologic examination, and another part was transferred to anaerobic transport medium for bacteriologic examination. RNA was isolated by means of a guanidinium isothiocyanate-acid phenol procedure, and cDNA was produced using herpesvirus-specific primers and reverse-transcription polymerase chain reaction amplification. Bacteriologic examination was performed according to established anaerobic culture methods. Of the 34 periapical lesions studied, 20 showed both HCMV and EBV, seven showed only HCMV, one showed only EBV, and six showed neither HCMV nor EBV. Herpes simplex virus was detected in two lesions. Higher occurrence of herpesvirus was detected in large versus small periapical lesions (p < 0.001) and in symptomatic versus asymptomatic periapical lesions (p < 0.001). A total of 18 microbial groups and an average of 2.1 to 3.0 bacterial groups were isolated from various categories of periapical lesions. The important finding of this study was that most teeth with necrotic pulp and periapical lesions harbored herpesviruses in periapical granulomatous tissue. Herpesvirus species in cooperation with endodontopathic bacteria may play major roles in the etiopathogenesis of aggressive types of periapical pathosis in humans.
Radiographic Evaluation of Root Canal Multiplicity in Mandibular First Premolars
Takatomo Yoshioka, DDS, PhD, Juan C. Villegas, DDS, MSc, Chihiro Kobayashi, DDS, PhD, and Hideaki Suda, DDS, PhD
The purpose of this study was to examine the accuracy of radiographic evaluation of root canal multiplicity in mandibular first premolars in vitro. One hundred thirty-nine extracted human mandibular premolars were used. Buccolingual radiographs were taken, and the number of canals in each tooth was determined on radiographs by four dentists using a view box. A sudden narrowing of the main canal was interpreted as a sign of multiple canals. After the radiographic evaluation, the tooth crown was removed. India ink was injected into the root canal system, and the root was cleared to observe the canal morphology. There was no statistically significant difference among the four dentists with respect to the coincidence rate (93%–96%) of the canal number evaluated on radiographs with that identified by cleared teeth observation (p > 0.05, one way analysis of variance). A sudden narrowing of the main canal on the radiograph was a good criterion to judge root canal multiplicity.
Relationship of Radiologic and Histologic Signs of Inflammation in Human Root-filled Teeth
Claudia R. Barthel, PD Dr., Stefan Zimmer, PD Dr., and Martin Trope, BDS, DMD
The aim of this study was to determine the relationship between histologic and radiologic signs of inflammation in human root-filled teeth. In addition, other factors with possible importance for apical inflammation were assessed. Fifty-three block sections of root-filled teeth were gathered from human cadavers. The blocks were radiographically exposed, sectioned, and stained with hematoxylin and eosin. Histologic sections were categorized as inflamed or uninflamed. Radiographically, the roots were assigned as apical lucency, widened periodontal ligament (PDL), or no lucency. Presence and contents of accessory canals were recorded (empty, tissue, or filling material). Statistical analysis was performed with the Chi-square test. All roots had accessory canals; 12 showed tissue remnants, and the others were empty. Of the cases, 49% were histologically uninflamed at the apex, and 52% appeared radiographically intact. The odds ratio of finding a histologically inflamed apex with radiologic lucency versus a radiographically intact apex was 9.2 (p _ 0.002). The odds ratio of finding a histologically uninflamed apex with a radiologically tight coronal seal versus an unacceptable seal was 3.7 (p _ 0.053). It may be concluded that there are relationships between radiologic and histologic signs of inflammation in human root canal-treated teeth. There appears to be a tendency that the radiologically determined quality of the coronal seal has an impact on the histologic state of the root-filled tooth. No relationship was detected between unfilled lateral or accessory canals and the status of inflammation at the periapex (51% inflamed, 49% uninflamed).
Repair of Root Perforations Using Mineral Trioxide Aggregate: A Long-term Study
Craig Main, DDS, Nina Mirzayan, DDS, Shahrokh Shabahang, DDS, MS, PhD, and Mahmoud Torabinejad, DMD, MSD, PhD
Root perforations adversely affect the prognosis of teeth. Inadequacy of the repair materials has been a contributing factor to the poor outcome of repair procedures. Mineral trioxide aggregate (MTA) is a relatively new material that is being successfully used to repair perforations. The purpose of this study was to evaluate the success rate of root perforation repairs using MTA. A list of all of the perforation repairs completed with MTA at an endodontic residency program was obtained. Sixteen cases were included that met the criteria for this study. Pretreatment, immediate posttreatment, and at least 1 year follow-up radiographs were evaluated in a double blind manner to determine the presence or absence of any pathologic changes adjacent to the perforation site. The results showed that all 16 cases demonstrated normal tissue architecture adjacent to the repair site at the recall visit. Teeth with existing lesions showed resolution of the lesion, and teeth without preoperative lesions continued to demonstrate absence of lesion formation at the follow-up visit. Based on the results of this study, MTA provides an effective seal of root perforations and shows promise in improving the prognosis of perforated teeth that would otherwise be compromised.
Antibacterial Activity of 2% Chlorhexidine Gluconate and 5.25% Sodium Hypochlorite in Infected Root Canal: In Vivo Study
Ertugrul Ercan, DDS, Tuncer Özekinci, DDS, Fatma Atakul, DDS, PhD, and Kadri Gül, DDS
In this study, the antibacterial activity of the different antibacterial solutions using as root canal irrigant was compared in the teeth with pulpal necrosis and with periapical pathosis. Thirty root canals of incisors and premolars of 20 patients were used. Before and after the root canal preparation, two canal samples were obtained by a harvesting method using a sterile paper point in the first appointment. During the biomechanical preparation, both irrigant solutions were used for each tooth which were randomly divided into two groups. Last samples were also obtained before the root filling procedure. Samples obtained from the root canals were subjected to microbiologic processing, including anaerobic incubation on trypticase soy agar for 5 to 7 days. After counting of CFU on the plates, we concluded that both chlorhexidine gluconate and sodium hypochlorite were significantly effective to reduce the microorganisms in the teeth with necrotic pulp, periapical pathologies, or both, and could be used successfully as an irrigant solution.
Proinflammatory Cytokine Profiles in Pulp Fibroblasts Stimulated with Lipopolysaccharide and Methyl Mercaptan
Jeffrey Coil, DMD, PhD, Esther Tam, DMD, and J. Douglas Waterfield, MSc, Fil.dr
Pulpal disease is intimately associated with the immune system’s response to bacteria products. Clinical pathology is mediated in part by the production of pyrogenic cytokines, especially interleukin (IL)-1, tumor necrosis factor (TNF)-a, and IL-6. Methyl mercaptan (CH3SH), a volatile sulfur compound produced by anaerobic Gram-negative bacteria, has been shown to contribute to the production of IL-1 by human mononuclear cells. In this report, we investigated the production of IL-1, TNF-a, and IL-6 by human pulp fibroblasts when stimulated for various periods of time with lipopolysaccharide (LPS) with or without the presence of CH3SH. We found that LPS and CH3SH had no effect on the production of IL-1 or TNF- a. However, LPS stimulated IL-6 production, and this production was augmented when CH3SH was present. We conclude that the volatile sulfur compound CH3SH plays a role in activation and modulation of the immune response through its role in production of IL-6.
Effectiveness of Sodium Hypochlorite in Preventing Inoculation of Periapical Tissues With Contaminated Patency Files
K. H. Izu, DDS, S. J. Thomas, DMD, P. Zhang, PhD, DDS, A. E. Izu, MS, and S. Michalek, PhD
The aim of this study was to analyze the effectiveness of 5.25% sodium hypochlorite (NaOCl) in preventing inoculation of periapical tissues with contaminated patency files. Twenty-eight extracted human permanent teeth with single canals were used in the study. Group I teeth were filled with NaOCl, and #15 stainless steel files contaminated with Streptococcus sanguis (ATCC #10556) were allowed to pass through the NaOCl into the culture medium. The teeth in group II were also filled with NaOCl, but the contaminated files used in group II canals were immersed in NaOCl for 10 s prior to being placed into the canals and cultured. The negative control group used sterile files (0% growth), the first positive control group used contaminated patency files in teeth with empty canals (100% growth), and the second positive control group placed contaminated files into broth next to teeth filled with NaOCl (to evaluate potential chlorine leakage; 100% growth). The experimental results showed no positive growth of S. sanguis for groups I and II, indicating that the NaOCl present in the canal after irrigation was sufficient to kill the test organism.
Reactions of Connective Tissue to Mineral Trioxide Aggregate and Amalgam
Mehmet Yaltirik, PhD, Hakan Ozbas, PhD, Bilge Bilgic, MD, and Halim Issever, MD
The purpose of this study was to evaluate the subcutaneous connective tissue reactions to ProRoot, mineral trioxide aggregate (MTA; Dentsply), and Oralloy, high-copper amalgam (Coltene). These materials were placed in polyethylene tubes and implanted into dorsal connective tissue of Wistar albino rats, and tissue biopsies were collected and histologically examined 7, 15, 30, 60, and 90 days after the implantation procedure. The presence of inflammation, predominant cell type, calcification, and thickness of fibrous connective tissue were recorded. Scores were defined as follows: 0, none or few inflammatory cells, no reaction; 1, <25 cells, mild reaction; 2, 25 to 125 cells, moderate reaction; 3, >125 cells, severe reaction. Fibrous capsule was categorized as “thin” when thickness was < 150 _m and “thick” at > 150 _m. Necrosis and formation of calcification were recorded. Both materials were well tolerated by the tissues in a 90-day evaluation period. One notable finding is the presence of dystrophic calcification in connective tissue adjacent to MTA; this finding is consistent with the hypothesis of hard tissue induction by this material.
The Influence of the Smear Layer on Dentinal Tubule Penetration Depth by Three Different Root Canal Sealers: An In Vitro Study
Andreas B. Kokkas, DDS, Asterios Ch. Boutsioukis, DDS, DDr, Leonidas P. Vassiliadis, DDS, DhD, and Christos K. Stavrianos, DDS, DDr
The effect of the smear layer on the penetration depth of three different root canal sealers into the dentinal tubules was examined in 64 recently extracted single-rooted teeth. After chemomechanical preparation, the samples were randomly divided in two equal groups. The smear layer remained intact in group A, whereas complete removal of the smear layer was performed in group B. Two roots from each group were used as controls. Ten roots from each group were obturated with laterally condensed gutta-percha points and sealers AH Plus, Apexit, and Roth 811, respectively. Examination in scanning electron microscope revealed that the smear layer obstructed all the sealers from penetrating dentinal tubules. In contrast, smear layer removal allowed the penetration of all sealers to occur to a varying depth. These findings suggest that smear layer plays an important role in sealer penetration into the dentinal tubules, as well as in the potential clinical implications.
A Comparison of Laterally Condensed Gutta-Percha, Thermoplasticized Gutta-Percha, and Mineral Trioxide Aggregate as Root Canal Filling Materials
Paul J. Vizgirda, DDS, Frederick R. Liewehr, DDS, MS, William R. Patton, DDS, MS, James C. McPherson, PhD, and T. B. Buxton, PhD
The purpose of this study was to evaluate the potential of using mineral trioxide aggregate as a root canal filling material by comparing its apical sealing ability with that of laterally condensed gutta-percha with sealer and high-temperature thermoplasticized gutta-percha with sealer in extracted bovine teeth. Sixty bovine incisors with single canals were prepared in a standard manner using LightSpeed instruments, randomly divided into three groups of 20 teeth, and obturated. The sealing ability of each technique was assessed by immersion in 1% methylene blue dye for 3 days. The teeth were cleared, and the linear extent of dye penetration was measured with a stereomicroscope. Data were analyzed by the Kruskal-Wallis one-way ANOVA followed by Dunn’s test. Canals filled with laterally condensed gutta-percha or thermoplasticized gutta-percha showed significantly less apical dye penetration than canals obturated with mineral trioxide aggregate (p < 0.001). There was no significant difference in leakage between the laterally condensed group and the thermoplasticized group. The results suggest that gutta- percha obturation may provide an apical seal that is superior to MTA.
Comparison Instrumentation Time of Conventional Reamers and Files versus a New, Noninterrupted, Flat-sided Design
Barry Lee Musikant, DMD, Brett I. Cohen, PhD, and Allan S. Deutsch, DMD
This in vitro study measured the time required to instrument and shape canals by conventional reamers and files compared with a newly introduced reamer and file system. This experiment was divided into four groups with 10 block samples for each group. The results of instrumentation time demonstrate that the noninterrupted flat-sided design (EZ-Fill SafeSider reamers) produced the fastest times for comparably shaped canals because of reduced engagement of the instrument with the walls of the canal compared with conventional instruments. The conventional designs for both reamers and files result in increased instrumentation time compared with their EZ-Fill SafeSider counterparts.
Influence of Instrument Size on Root Canal Debridement
Najia Usman, DDS, J. Craig Baumgartner, DDS, PhD, and J. Gordon Marshall, DMD
Files of Greater Taper (GT) are rotary nickel-titanium files of three tapers (0.06, 0.08, 0.10) with file tips of sizes 20, 30, and 40. The purpose of this study was to compare in an in situ model the efficacy of root canal debridement in the apical 3 mm when instrumenting to a GT size 20 or a GT size 40 at working length. Twenty matched human cadaver teeth with 32 canals were decoronated at the cementoenamel junction and instrumented with rotary Files of GT to either GT size 20 or GT size 40. Sodium hypochlorite, EDTA, and RC Prep were chemical aids for debridement. The teeth were extracted; decalcified; sectioned at 0.5 mm, 1.5 mm, and 2.5 mm from the apex; and prepared for histologic examination and quantification of remaining debris. No differences were found between each level within each apex size group; however, the GT size 20 group left significantly more debris in the apical third compared with the GT size 40 group. A regression analysis showed that the apical third cleanliness could be predicted mainly by instrument size and to a lesser extent by the canal length. Irrigant volume, number of instrument changes, and depth of penetration of irrigation needle were not likely to explain differences in debridement.
Effect of Medications for Root Canal Treatment on Bonding to Root Canal Dentin
Ali Erdemir, DDS, PhD, Hale Ari, DDS, PhD, Hakan Güngünes, Physics, PhD, and Sema Belli, DDS, PhD
Use of resin-based restorative materials recently has become widely accepted for treatment of endodontically treated teeth. However, some solutions routinely used during endodontic treatment procedures may have an effect on bond strengths of adhesive materials to root canal dentin. The purpose of this in vitro study was to evaluate the effect of various medications on microtensile bond strength to root canal dentin. Fourteen extracted human single-rooted teeth were used. The crowns and the pulp tissues were removed. The root canals were then instrumented and widened to the same size. The teeth were randomly divided into seven groups of two teeth each. The root canal dentin walls of the roots were treated with 5% sodium hypochloride (NaOCl), 3% hydrogen peroxide (H2O2), the combination of H2O2 and NaOCl, or 0.2% chlorhexidine gluconate for 60 s; or calcium hydroxide or formocresol for 24 h. The teeth in control group were irrigated with water. The root canals were obturated using C&B Metabond. After 24 h of storage in distilled water, serial 1-mm-thick cross-sections were cut, and approximately 12 samples were obtained from each group. Microtensile bond strengths to root canal dentin were then measured by using an Instron machine. The data were recorded and expressed as MPa. The results indicated that NaOCl, H2O2, or a combination of NaOCl and H2O2 treatment decreased bond strength to root canal dentin significantly (p < 0.05). The teeth treated with chlorhexidine solution showed the highest bond strength values (p < 0.05). In conclusion, chlorhexidine is an appropriate irrigant solution for root canal treatment before adhesive post core applications.
Mental Nerve Paresthesia Associated with an Adhesive Resin Restoration: A Case Report
Osvaldo Zmener, DDS, Dr Odont
A case is reported in which mental nerve paresthesia was associated with an adhesive resin restoration placed in direct contact with the pulp of a mandibular molar. The restoration was removed, and the paresthesia had completely resolved after nonsurgical endodontic therapy. Epicutaneous patch testing response indicated a possible causal relationship between the filling material and paresthesia.
MTA for Obturation of Mandibular Central Incisors with Open Apices: Case Report
Mikako Hayashi, DDS, PhD, Ayako Shimizu, DDS, and Shigeyuki Ebisu, DDS, PhD
The case reported demonstrates dramatic healing of the periapical region of retreated root canals with open apices by the successful use of mineral trioxide aggregate (MTA). Unsuccessful conventional root canal therapy for the mandibular central incisors had been followed by surgical treatment. The severely damaged root canals were obturated using MTA in anticipation of the formation of artificial apical plugs. The treated teeth were asymptomatic, and radiographic examination demonstrated apparent regeneration of periradicular tissue 2 years after the obturation. MTA can be considered a very effective material to promote regeneration of apical tissue, even in teeth with large open apices.