Evaluation of Protocols for Field Decontamination Before Bacterial Sampling of Root Canals for Contemporary Microbiology Techniques
Yuan-ling Ng, David Spratt, Srimathy Sriskantharajah, and Kishor Gulabivala
Cytomegalovirus and Epstein-Barr Virus Active Infection in Periapical Lesions of Teeth with Intact Crowns
M. Sabeti, J. H. Simon, H. Nowzari, and J. Slots
Histological and Scanning Electron Microscopy Assessment of Various Vital Pulp-Therapy Materials
Mercedes S. Dominguez, David E. Witherspoon, James L. Gutmann, and Lynnne A. Opperman
Quantitative Analysis of the Solubilizing Action of MTAD, Sodium Hypochlorite, and EDTA on Bovine Pulp and Dentin
Richard E. Beltz, Mahmoud Torabinejad, and Manucher Pouresmail
Efficacy of Calcium Hydroxide: Chlorhexidine Paste as an Intracanal Medication in Bovine Dentin
Matthew D. Evans, J. Craig Baumgartner, Saeng-usa Khemaleelakul, and Tian Xia
Additive Antimicrobial Activity of Calcium Hydroxide and Chlorhexidine on Common Endodontic Bacterial Pathogens
Andreas Podbielski, Axel Spahr, and Bernd Haller
Cleaning Efficiency of Nickel-Titanium GT and .04 Rotary Files when used in a Torque-Controlled Rotary Handpiece
Calvin B. Suffridge, Gary R. Hartwell, and Thomas L. Walker
Conventional versus Storage Phosphor-Plate Digital Images to Visualize the Root Canal System Contrasted with a Radiopaque Medium
Hani J. Naoum, Nicholas P. Chandler, and Robert M. Love
Taurodontism: An Endodontic Challenge. Report of a Case
Igor Tsesis, Arie Shifman, and Arieh Y. Kaufman
Identifying Multiplanar Root Canal Curvatures Using Stainless-Steel Instruments
Charles E. Jerome, and Robert J. Hanlon Jr.
Evaluation of Protocols for Field Decontamination Before Bacterial Sampling of Root Canals for Contemporary Microbiology Techniques
Yuan-ling Ng, MSc, MRD RCS, David Spratt, PhD, Srimathy Sriskantharajah, BSc, and Kishor Gulabivala, MSc, FDS, RCS
The effectiveness of sodium hypochlorite (NaOCI) (2.5%) or iodine (10%) for decontamination of the operation field (tooth, rubber dam, and gasket [Oraseal]) was compared by using bacterial cultivation. In addition, the final samples were also assessed for bacteria by using polymerase chain reaction. Teeth (n = 63) receiving root canal treatment were polished with pumice, isolated with rubber dam, and their margins sealed with Oraseal. The operation field was disinfected with hydrogen peroxide (30%), followed by iodine (n = 31) or NaOCI (n = 32), before and after access cavity preparation. The operation field was sampled before and after each decontamination, giving four samples per field. After the final decontamination, there was no significant difference (p = 0.602, 0.113, 0.204) in recovery of cultivable bacteria from various sites in either group. However, bacterial DNA could be detected significantly (p = 0.010) more frequently from the tooth surfaces after iodine (45%) compared with NaOCI (13%) decontamination, although on the rubber dam or Oraseal surfaces there was no difference. Root canal sampling for polymerase chain reaction might be better preceded by NaOCI decontamination than by iodine, based on the findings.
Cytomegalovirus and Epstein-Barr Virus Active Infection in Periapical Lesions of Teeth with Intact Crowns
M. Sabeti, J. H. Simon, H. Nowzari, and J. Slots
Herpesviruses seem to play an important role in the pathogenesis of aggressive periodontitis and may also contribute to periapical pathosis. This study determined the presence of human cytomegalovirus, Epstein-Barr virus, and herpes simplex virus productive infection in five symptomatic periapical lesions of teeth having intact crowns and calcified necrotic pulps. Periapical samples were collected in conjenction with peripaical surgery and kept frozen until virological examination. Reverse transcription-polymerase chain reaction was used in herpesviral identification. RNA was isolated from periapical tissue by a guanidinium isothiocyanate-acid phenol proceedure. cDNAs were generated from highly conserved regions of the test viruses usinga pre-amplification kit. Sensitivity and validity of the PCR-primers were determined according to established methods. Amplification products were indentified using gel electrophoresis. Human cytomegalovirus and Epstein-Barr virus dual transcription was detected in all five periapical lesions studied. Herpes simplex virus transcript was not identified in any lesion. The present data suggest that human cytomegalovirus or Epstein-Barr virus activation participate in the pathogenesis of symptomatic periapical lesions. We hypothesize that periapical active herpesvirus infection impairs local defenses, thereby inducing ovegrowth of endodontopathic bacteria and the clinical flare-up of inflammation.
Histological and Scanning Electron Microscopy Assessment of Various Vital Pulp-Therapy Materials
Mercedes S. Dominguez, David E. Witherspoon, James L. Gutmann, and Lynnne A. Opperman
Pulp capping and pulpotomy procedures were performed on 15 male mongrel dogs. Three materials were used: calcium hydroxide, acid-etched dentin bonding, and mineral trioxide aggregate. Six of the animals were killed at 50 days and nine were killed at 150 days. Samples from 11 dogs were used for histological evaluation, and the remaining dog samples were used for scanning electron microscopy evaluation. Each slide was graded histologically according to previously published criteria. Scanning electron microscopy analysis was performed, and the weight percentage of elements found in the dentin of a nontreated tooth versus the bridge formed in the exposed specimen was established. By evaluating pulp inflammation in vital pulp-therapy treatments, it was found that mineral trioxide aggregate was not significantly different from the untreated control group, both in pulp capping procedures at 50 days (p = 0.357) or 150 days (p = 0.198) and pulpotomy procedures at 50 days (p = 0.357) or 150 days (p = 0.198). Moreover, histologically mineral trioxide aggregate was a considerably better material than calcium hydroxide or acid-etched dentin bonding in maintaining the integrity of the pulp.
Quantitative Analysis of the Solubilizing Action of MTAD, Sodium Hypochlorite, and EDTA on Bovine Pulp and Dentin
Richard E. Beltz, PhD, Mahmoud Torabinejad, DMD, MSD, PhD, and Manucher Pouresmail, DMD
Necrotic bovine pulp and dentin were used in this study as model tissues to represent the organic and inorganic components of the smear layer present in instrumented root canals. The capabilities of endodontic irrigants to dissolve pulverized forms of these tissues were compared. Lyophilized tissue samples were mixed for 2 h at 37°C with MTAD, three concentrations of sodium hypochlorite (NaOCI), 17% EDTA, or isotonic saline. Un-dissolved tissues were rinsed with water and lyophilized. The change in tissue weight after exposure to an irrigant was measured to quantify solubilization. The results showed that various concentration of NaOCI removed organic components of pulp and dentin effectively. As pulp solubilizers 5.25% and 2.60% NaOCI were equal (>90%), and 5.25% NaOCI was capable of dissolving virtually the entire organic component of dentin. EDTA was capable of solubilizing inorganic material in dentin and organic material in pulp and likely also in dentin. It dissolved > 70% of the dentin and >51% of the pulp. The solubilizing effects of MTAD on pulp and dentin were somewhat similar to those of EDTA. The major difference between the actions of these solutions was a high binding affinity of doxycycline present in MTAD for the dentin.
Efficacy of Calcium Hydroxide: Chlorhexidine Paste as an Intracanal Medication in Bovine Dentin
Matthew D. Evans, DMD, J. Craig Baumgartner, DDS, PhD, Saeng-usa Khemaleelakul, DDS, and Tian Xia, DDS
The purpose of this study was to evaluate the antibacterial efficacy of an intracanal medication composed of calcium hydroxide with 2% chlorhexidine. Dentin from 24 bovine incisors was used. The incisors were made into standardized cylindrical segments of dentin and infected with Enterococcus faecalis. They were then treated with an intracanal paste composed of calcium hydroxide and sterile water or an intracanal paste composed of calcium hydroxide and sterile water or an intracanal paste composed of calcium hydroxide and 2% chlorhexidine for 1 week. Dentin shavings were collected, suspended in solution, and spread on brain-heart infusion agar. After incubation, colony-forming units were enumerated. The amount of bacteria per mg of dentin was determined. The calcium hydroxide paste with 2% chlorhexidine was significantly more effective at killing E. faecalis in the dentinal tubules than calcium hydroxide with water.
Additive Antimicrobial Activity of Calcium Hydroxide and Chlorhexidine on Common Endodontic Bacterial Pathogens
Andreas Podbielski, Dr. rer. nat. Dr. med., Axel Spahr, Dr. med. dent., and Bernd Haller, Dr. med. dent.
It is an established procedure to use calcium hydroxide [Ca(OH)2] as a therapeutic component to achieve sterilization of infected root canals. Unfortunately, some bacterial species are relatively resistant to Ca(OH)2 and are therefore associated with treatment failures. The objective of this study was to identify combinations of substances that improve antimicrobial activity. Ca(OH)2 was used as a suspension or as a component of gutta-percha points. Efficacy of killing was compared for (a) Ca(OH)2 suspension alone; (b) zinc oxide (ZnO) points alone; (c) Ca(OH)2 suspension combined with ZnO points; (d) Ca(OH)2 suspension combined with ZnO/chlorhexidine points; and (e) Ca(OH)2 points combined with ZnO/chlorhexidine points. Common endodontopathogenic bacterial species (Enterococcus faecalis, Fusobacterium nucleatum, Peptostreptococcus micros, Porphyromonas gingivalis, Streptococcus intermedius) in pure cultures served as target organisms. In the in vitro assay, the antibacterial substances and approximately 107 colony forming units of test bacteria were co-incubated in diluted human serum under growth conditions appropriate for the single bacterial species. Samples were taken on days 0, 1, 2, 4, 7 and 14 of incubation and viable counts determined. Gram-negative bacteria were sufficiently killed by Ca(OH)2 alone. Combinations with other agents did not improve the killing kinetics. For the inactivation of the Gram-positive bacteria P. micros and S. intermedius, a combination of Ca(OH)2 and ZnO/chlorhexidine, killed the bacteria faster than Ca(OH)2 suspension with ZnO/chlorhexidine points lead to a faster decrease in the overall number of viable bacteria, but no test conditions lead to the complete loss of culture viability. The results of this study support the use of a combination of Ca(OH)2 and chlorhexidine for faster eradication of P. micros and S. intermedius from infected root canals.
Cleaning Efficiency of Nickel-Titanium GT and .04 Rotary Files when used in a Torque-Controlled Rotary Handpiece
Calvin B. Suffridge, DDS, Gary R. Hartwell, DDS, MS, and Thomas L. Walker, DDS
This study determined if the cleaning efficiency of nickel-titanium rotary files in an endodontic electric handpiece using a no-torque control setting was superior to that obtained when using the torque-control feature. Fifty extracted human anterior teeth with straight canals were divided into two groups of 20 and two control groups of 5. Canals were instrumented with GT and .04 ProFile nickel-titanium files until a size of 35 advanced to working length. Samples were sectioned and the apical 6 mm of the canal was photographed (x20) and projected onto a 3- x 4-foot grid with squares measuring 0.5 inches each. Total debris was the percentage of the number of squares containing debris versus the total number of squares. The teeth in the torque-controlled group showed an average of 24.99% debris versus 15.55% for the teeth in the no-torque group. The difference was not statistically significant; therefore, no difference can be said to exist between the two torque settings in terms of cleaning efficiency.
Conventional versus Storage Phosphor-Plate Digital Images to Visualize the Root Canal System Contrasted with a Radiopaque Medium
Hani J. Naoum, BDS, MDS, Nicholas P. Chandler, BDS, MSc, FDSRCPS, FDSRCS, FFDRCSI and Robert M. Love, BDS, MDS, PhD, FRACDS
The pulp tissue was removed from 20 mandibular first molar teeth using 2.5% NaOCI irrigation and hand files. The dried canals were infused with radiopaque contrast medium. Standardized conventional and Digora digital images were obtained of each tooth positioned in a dried mandible at 0- and 30-degree horizontal angulations. Three evaluators rated the image clarity of the 0- and 30 degree original, enhanced, three-dimensional, zoom, and reverse digital images modes as superior, equal, or inferior to corresponding 0- and 30- degree conventional radiographs. The ratings were compared using the Wilcoxon signed rank test. The original, three-dimensional, zoom, or reverse digital images were inferior to the conventional radiographs for clarity of canal anatomy. The enhanced digital images were not always inferior to the conventional radiographs and were the only images superior to the original digital images. Overall, evaluators rated the image clarity of root canal anatomy on conventional radiographs better than on Digora images. However, factors in the experimental design may have contributed to this result.
Taurodontism: An Endodontic Challenge. Report of a Case
Igor Tsesis, DMD, Arie Shifman, DMD, and Arieh Y. Kaufman, DMD
Taurodontism is a morphoanatomical change in the shape of a tooth, which usually occurs in multirooted teeth. An enlarged body and pulp chamber, as well as apical displacement of the pulpal floor, are characteristic features. Endodontic treatment of a taurodont tooth is challenging, because it requires special care in handling and identifying the number of root canals. A case of endodontic treatment of a maxillary first molar with taurodontism is presented.
Identifying Multiplanar Root Canal Curvatures Using Stainless-Steel Instuments
Charles E. Jerome, DDS, and Robert J. Hanlon Jr., DMD
Information obtained from careful observation of stainless-steel hand file deformation can be a critical step in efficient root canal space debridement. Secondary and tertiary canal curvatures that occur most often in the proximal view have been reported in the literature. Except in teeth that are clinically rotated, there is currently no method for observing the proximal view of root canal systems. This article presents a simple clinical procedure for detacting the three-dimensional anatomy of root canal spaces. We refer to the procedure as file molding.