Detection of Receptor Activator of NF-κ β Ligand in Apical Periodontitis
M. Sabeti, J. Simon, V. Kermani, Y. Valles, and I. Rostein
A novel protein known as receptor activator of NF-κ β ligand (RANK-L) has been identified as a potential osteoclast differentiation factor. However, comparatively little is known about the expression of RANK-L in the pathogenesis of periradicular lesions. In this study, RANK-L expression was evaluated in biopsy specimens from apical periodontitis. Tissue samples from 21 periapical lesions were collected. RANK-L mRNA was isolated by using the guanidinium isothiocyanate acid phenol method. This was followed by generation of cDNA using specific primer for RANK-L by reverse transcription polymerase chain reaction amplification. RANK-L expression in each periapical sample was assessed by agarose gel electrophoresis. Gel electrophoresis analysis showed a single band of 385 bp corresponding to RANK-L in every periapical lesion. By contrast, normal control tissue showed no detectable RANK-L mRNA expression. In conclusion, RANK-L may play a role in apical periodontitis–induced bone resorption.
Soft Tissue Management in Endodontic Surgery
Peter Velvart, DMD, and Christine I. Peters, DMD
Modern endodontic surgery involves both root-end preparation and proper sealing of all apical portals of exit. Both components are requirements for mechanical and biological success, but the management of soft tissues becomes increasingly important for an esthetically successful treatment. A healthy appearance of soft tissues plays an important role in the esthetic outcome of periradicular surgery. This is true considering maintenance of attachment levels and regarding the amount of possible recession after surgical procedures. Complete, recession-free and predictable healing of gingival tissue is one important goal of endodontic surgical treatment. A critical review of currently used techniques based on clinical and scientific data reveals great potential for improvements. Possible reasons for scar formation and recession specifically in healthy periodontal conditions requiring surgical endodontic intervention are highlighted. Based on anatomical considerations various incision types are evaluated and recommendations made. Clear understanding of wound closure and tissue-healing patterns call for the use of atraumatic procedures, nonirritating suture materials and adequate suturing techniques. This article gives an overview and guidance for integrating current and new successful flap designs and wound closure methods. The methods described have the intention of maintaining the attachment level and avoiding postoperative recession after surgical endodontic therapy.
Pulp-Dentine Complex Changes and Root Resorption During Intrusive Orthodontic Tooth Movement in Patients Prescribed Nabumetone
Paula A. Villa, Giovanni Oberti, Cesar A. Moncada, Olga Vasseur, Alejandro Jaramillo, Diego Tobón, and Jaime A. Agudelo
Pulpitis, external root resorption, and pain may be experienced during orthodontic movement.
The use of nonsteroidal anti-inflammatory drugs (NSAIDs) has been suggested to control these changes. The purpose of this study was to observe pulp-dentinal reactions, root resorption, tooth pain, and tooth movement after the application of a 4-ounce intrusive orthodontic force to human maxillary first premolars in patients given the NSAID nabumetone. Thirty-four maxillary first premolars were evaluated. A placebo was prescribed to 17 patients after an intrusive force was activated and reactivated for an 8-week period on the right side. The same procedure was repeated on the left side after patients were given nabumetone. Pulp-dentinal reactions and external root resorption were evaluated by histology. Pain and movement were also evaluated. Nabumetone was found to be useful in reducing pulpitis, external root resorption, and pain caused by intrusive orthodontic movement, without altering tooth movement in response to the application of orthodontic force.
Apical Diffusion of Calcium Hydroxide in an in vitro Model
Geoffrey H. Robert, DDS, Frederick R. Liewehr, DDS, MS, Thomas B. Buxton, PhD, and
James C. McPherson III, PhD
An in vitro agar model was developed to study the effect of intracanal medicaments on periapical tissues and was used to study the diffusion of three calcium hydroxide (Ca(OH)₂) medicaments of varying viscosity through simulated root canals with various sizes of apical foramina. Experimental medicaments were added to pipette tips used to represent tooth roots, which were fixed in syringes containing brain heart infusion agar and calciumreactive dye. OH⁻ and Ca⁺⁺ concentrations were measured in the agar at 30 minutes and 24 hours. Ca⁺⁺ concentration and pH increased with larger aperture sizes, and higher pH and Ca⁺⁺ diffusion was produced by a 10% Ca(OH)₂ solution than was produced by Pulpdent or a Ca(OH)₂ paste. The results suggest that the properties of the Ca(OH)₂- containing vehicle could affect the action of the medicament in the periapical tissues.
Dentinal Tubule Disinfection Using Three Calcium Hydroxide Formulations
Stephen J. Cwikla, DMD, Myriam Bélanger, PhD, Steeve Giguère, DVM, PhD, Ann Progulske-Fox, PhD, and Frank J. Vertucci, DMD
The objective of this study was to determine the antibacterial efficacy of three calcium hydroxide (CH) formulations using an in vitro model of Enterococcus faecalis dentinal tubule infection. CH mixed with water (CH), CH mixed with iodine-potassium iodide (CH+IKI), and CH mixed with iodoform and silicone oil (Metapex) were tested. Human cylindrical dentin specimens infected with E. faecalis were filled with disinfectants and incubated for 1 week. Dentin powder samples collected with ISO 018 burs showed a statistically significant reduction in E. faecalis for all three experimental groups in comparison with untreated control specimens. Statistically significant differences were also found between the three experimental groups. Metapex was the most effective dentinal tubule disinfectant, followed by CH+IKI and then CH. Similar results were observed at greater dentin tubule depths (ISO 021 burs) with the exception that intracanal treatment with CH resulted in significantly higher numbers of E. faecalis in comparison with untreated control specimens.
Effect of pH Modified EDTA Solution to the Properties of Dentin
Kaoru Nakashima, DDS, Rintaro Terata, DDS, PhD
The purpose of this study was to evaluate the influence of smear layer removal with 3% EDTA solution (pH of 9.0) on the dentin in terms of the permeability of root canal disinfectants into the dentin, wetting by endodontic sealer, and adhesive strength of the sealer. Three types of disinfectant (formalin cresol, phenol, and calcium hydroxide) and 4 types of endodontic sealers (included eugenol, non-eugenol, polycarboxylic acid, and resin) were used. The contact angle between endodontic sealer solution and dentin decreased in the 3% EDTA group but increased in the 15% EDTA. The adhesive strength of endodontic sealer to dentin increased in the EDTA groups for all types of sealers. The permeability of root canal disinfectants increased to similar degrees in the 3% and the 15% EDTA groups. In comparing these properties, we propose that the 3% EDTA is more useful for clinical applications.
Antiproliferative Effect of Mineral Trioxide Aggregate, Zinc Oxide-Eugenol Cement, and Glass-Ionomer Cement Against Three Fibroblastic Cell Lines
Elisabeth A. Koulaouzidou, DDS, PhD, Konstantinos T. Papazisis, MD, PhD, Nikolaos A. Economides, DDS, MSc, PhD, Panagiotis Beltes, DDS, PhD, and Alexander H. Kortsaris, PhD
An important requirement for dental materials placed in direct contact with living tissues is biocompatibility. The purpose of this study was to evaluate the antiproliferative activity of three dental materials (mineral trioxide aggregate, zinc oxide-eugenol cement, and glass-ionomer cement) against a panel of established fibroblastic cell lines (L929, BHK21/C13, and RPC-C2A). The materials were prepared according to the manufacturer’s instructions and were tested in insert wells for 12, 24, and 48 h. Cell number fraction was estimated by the sulforhodamine-B assay, in reference to controls. The degree of antiproliferative effect in ascending order was mineral trioxide aggregate, glass-ionomer cement, and zinc oxide-eugenol cement in all cell lines tested.
SEM Observations of Nickel-Titanium Rotary Endodontic Instruments that Fractured During
Clinical Use
Satish B. Alapati, BDS, MS, William A. Brantley, PhD, Timothy A. Svec, DDS, MS, MS, John M. Powers, PhD, John M. Nusstein, DDS, MS, and Glenn S. Daehn, PhD
Numerous discarded ProFile GT, ProFile, and Pro-Taper nickel-titanium rotary instruments obtained from two graduate endodontic clinics were examined by scanning electron microscopy. These instruments had an unknown history of clinical use and had fractured or experienced considerable permanent torsional deformation without complete separation. The failure processes generally exhibited substantial ductile character, evidenced by a dimpled rupture fracture surface. Crack propagation at grain boundaries and cleavage surfaces indicative of transgranular fracture were observed for some specimens. It appeared that oxide particles from the manufacturing process served as nucleating sites for the microvoids, leading to dimpled rupture. A previously unreported fracture mode also was observed, in which crack propagation, approximately parallel to the local flute orientation, connected pitted regions on the surface. Combining present and previous scanning electron microscopy observations of clinically failed instruments, suggestions are offered for improving their fracture resistance.
The Effect of Endodontic Solutions on Resorcinol-Formalin Paste in Teeth
Madelyn G. Gambrel, D.D.S., Gary R. Hartwell, D.D.S., M.S., Peter C. Moon, Ph.D., M.S., Jared W. Cardon, B.S.
This study determined if any of six endodontic solutions would have a softening effect on resorcinolformalin paste in extracted teeth, and if there were any differences in the solvent action between these solutions. Forty-nine single-rooted extracted teeth were decoronated 2 mm coronal to the CEJ, and the roots sectioned apically to a standard length of 15 mm. Canals were prepared to a 12 mm WL and a uniform size with a #7 Parapost drill. Teeth were then mounted in a cylinder ring with acrylic. The resorcinol-formalin mixture was placed into the canals and was allowed to set for 60 days in a humidor. The solutions tested were 0.9% sodium chloride, 5.25% sodium hypochlorite, chloroform, Endosolv R (Endosolv R®), 3% hydrogen peroxide, and 70% isopropyl alcohol. Seven samples per solution were tested and seven samples using water served as controls. One drop of the solution was placed over the set mixture in the canal, and the depth of penetration of a 1.5-mm probe was measured at 2, 5, 10, and 20 min using a dial micrometer gauge. A repeated-measures ANOVA showed a difference in penetration between the solutions at 10 min (p = 0.04) and at 20 min (p = 0.0004). At 20 min, Endosolv R, had significantly greater penetration than 5.25% sodium hypochlorite (p = 0.0033) and chloroform (p _ 0.0018); however, it was not significantly better than the control (p = 0.0812). Although Endosolv R, had statistically superior probe penetration at 20 min, the softening effect could not be detected clinically at this time.
Levels of Evidence for the Outcome of Endodontic Surgery
Cary Mead, DDS, Salvia Javidan-Nejad, DDS, Miguel E. Mego, DDS, Brandon Nash, DDS, and Mahmoud Torabinejad, DMD, MSD, PhD
The purpose of this investigation was twofold: (1) to search for clinical articles pertaining to success and failure of periapical surgery and (2) to assign levels of evidence to these studies except case reports. Electronic and manual searches were conducted to identify all the literature regarding success and failure of periapical surgery since 1970. Articles were reviewed, and each article was assigned to a level of evidence from 1 (highest level) to 5 (lowest level). This search located 79 clinical studies. Among these studies, there were no level of evidence–1 randomized clinical trial studies. Five of the seven level of evidence–2 randomized clinical trials compared postoperative pain between surgical and nonsurgical retreatment. Only two level of evidence–2 randomized clinical trials compared the outcomes of surgical treatment with that of nonsurgical treatment. The majority of frequently quoted “success and failure” studies were case series (level of evidence 4).
Endodontic Management of Dens Evaginatus of Maxillary Central Incisors: A Rare Case Report
Sunil Kumar Vasudev, BDS, and Beena Rani Goel, BDS, MDS
Dens evaginatus is a disturbance in tooth development that produces a tubercle of hard tissue on the surface of the tooth. While prophylactic pulp capping is recommended for vital teeth, teeth with necrotic pulps require endodontic therapy or extraction. This rare case of a 24-yr-old Indian male with affected maxillary central incisors demonstrates the clinical consequences of dens evaginatus.
Antimicrobial Efficacy of Chlorhexidine and Two Calcium Hydroxide Formulations Against Enterococcus faecalis
Edgar Schäfer, Prof. Dr. med. dent., and Klaus Bössmann, Prof. Dr. rer. nat.
The purpose of this study was to investigate the efficacy of chlorhexidine (CHX) and calcium hydroxide (Ca(OH)₂) against Enterococcus faecalis in vitro. Extracted single-rooted human teeth were instrumented up to size 40. After removal of the smear layer, an inoculum of E. faecalis was inserted into the root canals. After incubation, the inoculum was removed and the root canals were filled with one of three different disinfectants: Ca(OH)₂ paste, CHX 2%, and a mixture of CHX and Ca(OH)₂ paste (n = 10 in each group). Control teeth were filled with water of standardized hardness (n = 10). The teeth were then incubated for 3 days. After incubation, each root canal was instrumented, and the removed dentin was examined microbiologically. CHX was significantly more effective against E. faecalis than was Ca(OH)₂ paste or a mixture of CHX with Ca(OH)₂ paste (p < 0.05). There was no increase in the efficiency of Ca(OH)₂ paste when CHX was added (p > 0.05). The results suggest that CHX is effective in the elimination of E. faecalis from dentinal tubules under the conditions of this study.
Susceptibilties of Two Enterococcus faecalis Phenotypes to Root Canal Medications
Mariam Abdullah, MClinDent, Yuan-Ling Ng, MRD, Kishor Gulabivala, FDS, RCSE, David R. Moles, PhD, and David A. Spratt, PhD
This study aimed to investigate and compare the efficacy of selected root canal irrigants and a medicament on a clinical isolate of Enterococcus faecalis grown as biofilm or planktonic suspension phenotype. A cell-dense pellet “presentation” prepared from planktonic phenotype was also tested. Each bacterial presentation was exposed to calcium hydroxide (pH 12.3), 0.2% chlorhexidine gluconate, 17% ethylene-diamine-tetra-acetic acid, 10% povidone iodine, or 3.0% sodium hypochlorite (NaOCl) for a range of time periods (1, 2, 4, 8, 15, 30, and 60 min). Phosphate buffered saline was used as a control agent. The difference in gradients of bacterial killing among the biofilm, planktonic suspension or pellet presentation was significant (p < 0.05) and dependent upon the test agent except in the case of NaOCl and calcium hydroxide where no difference could be detected. NaOCl was the most effective agent and achieved 100% kills for all presentations of E. faecalis after a 2 min contact time.
Comparison of the Obturation Density of Cold Lateral Compaction Versus Warm Vertical Compaction Using the Continuous Wave of Condensation Technique
Christopher S. Lea, DDS, Michael J. Apicella, DDS, Pete Mines, DDS, Peter P. Yancich, DDS, and M. Harry Parker, DDS, MS
The purpose of this in vitro study was to compare quantitatively the density of standard cold lateral gutta-percha compaction and warm vertical compaction by using the continuous wave of condensation technique. Forty transparent acrylic blocks with 30-degree, curved root canals were instrumented using Gates Glidden burs and Profile 0.06 taper rotary nickel-titanium files in a crown-downmanner. The blocks were weighed and randomly assigned to two evenly distributed groups. Group A was obturated with the cold lateral-compaction technique using mediumfine, gutta-percha accessory points until the canal was completely filled. Group B was obturated with the continuous wave of condensation technique until the canal was completely filled. The blocks were weighed again after obturation. Data were analyzed using a two-sample t test at the 5% significance level. Results demonstrated that the continuous wave of condensation technique resulted in a significantly greater density compared with cold lateral compaction. Warm vertical compaction using the continuous wave of condensation technique in acrylic blocks resulted in a greater gutta-percha fill by weight compared with standard cold lateral compaction.