Regenerative Endodontics: A Review of Current Status and a Call for Action
Peter E. Murray, BSc(Hons), PhD, Franklin Garcia-Godoy, DDS, MS, Kenneth M. Hargreaves, DDS, PhD
Millions of teeth are saved each year by root canal therapy. Although current treatment modalities offer high levels of success for many conditions, an ideal form of therapy might consist of regenerative approaches in which diseased or necrotic pulp tissues are removed and replaced with healthy pulp tissue to revitalize teeth. Researchers are working toward this objective. Regenerative endodontics is the creation and delivery of tissues to replace diseased, missing, and traumatized pulp. This review provides an overview of regenerative endodontics and its goals, and describes possible techniques that will allow regenerative endodontics to become a reality. These potential approaches include root-canal revascularization, postnatal (adult) stem cell therapy, pulp implant, scaffold implant, three-dimensional cell printing, injectable scaffolds, and gene therapy. These regenerative endodontic techniques will possibly involve some combination of disinfection or debridement of infected root canal systems with apical enlargement to permit revascularization and use of adult stem cells, scaffolds, and growth factors. Although the challenges of introducing endodontic tissue engineering therapies are substantial, the potential benefits to patients and the profession are equally ground breaking. Patient demand is staggering both in scope and cost, because tissue engineering therapy offers the possibility of restoring natural function instead of surgical placement of an artificial prosthesis. By providing an overview of the methodological issues required to develop potential regenerative endodontic therapies, we hope to present a call for action to develop these therapies for clinical use.
Monoblocks in Root Canals: A Hypothetical or a Tangible Goal
Franklin R. Tay, BDSc (Hons), PhD, David H. Pashley, DMD, PhD
The term monoblock has become familiar in the endodontic literature with recent interest in the application of dentin adhesive technology to endodontics. Endodontic monoblocks have generated controversial discussions among academicians and clinicians as to whether they are able to improve the quality of seal in root fillings and to strengthen roots. This review attempts to provide a broader meaning to the term monoblock and to see how this definition may be applied to the materials that have been used in the past and present for rehabilitation of the root canal space. The potential of currently available bondable materials to achieve mechanically homogeneous units with root dentin is then discussed in relation to the classical concept in which the term monoblock was first employed in restorative dentistry and subsequently in endodontics.
Factors Affecting Outcomes for Single-Tooth Implants and Endodontic Restorations Scott L. Doyle, DDS, MS, James S. Hodges, PhD, Igor J. Pesun, DDS, MS, Michael K. Baisden, DDS, Walter R. Bowles, DDS, MS
Initial root canal therapy and implant placement are both common treatment modalities, and, as such, prognostic factors that influence the treatment outcomes of these two restorations should be identified. In a retrospective chart review, 196 implant restorations and 196 matched initial nonsurgical root canal treated (NSRCT) teeth in patients were evaluated for four possible outcomes—success, survival, survival with intervention, and failure. Results showed that smokers had fewer successes and more failures in both groups (p = 0.0001), whereas NSRCT outcomes were affected by periradicular periodontitis (p = 0.001), post placement (p = 0.013), and overfilling (p = 0.003). Outcomes for both groups were not significantly affected by diabetes, age, or gender. Implant group outcomes were not affected by implant length (from 10 to 16 mm), diameter (from 3.25 to 5.5 mm), or an adjacent endodontically treated tooth, nor were NSRCT outcomes affected by the number of appointments for the procedure.
Comparison of 4% Articaine with 1:100,000 Epinephrine and 2% Lidocaine with 1:100,000 Epinephrine When Used as a Supplemental Anesthetic
Paul A. Rosenberg, DDS, Ketan G. Amin, DMD, Yigal Zibari, DDS, Louis M. Lin, DMD, PhD
A randomized, double-blind trial was conducted to compare the efficacy of 4% articaine with 1:100,000 epinephrine and 2% lidocaine with 1:100,000 epinephrine when used as a supplemental anesthetic. Forty-eight patients with irreversible pulpitis requiring supplemental buccal infiltration for endodontic therapy were given either 4% articaine with 1:100,000 epinephrine or 2% lidocaine with 1:100,000 epinephrine in a double-blind manner. A standard VAS pain scale was used to evaluate the patient’s response to pain after a supplemental injection. The mean VAS score after supplemental anesthesia was 15.28 for 4% articaine with 1:100,000 epinephrine and 19.70 for 2% lidocaine with 1:00,000 epinephrine. The mean percentage change in VAS score was 70.5 and 62.2% for articaine and lidocaine, respectively. There was no statistically significant difference in the VAS pain score between 4% articaine with 1:00,000 epinephrine and 2% lidocaine with 1:00,000 epinephrine as a supplemental anesthetic.
Use of the Cold Test as a Measure of Pulpal Anesthesia During Endodontic Therapy: A Randomized, Blinded, Placebo-Controlled Clinical Trial
Grace W. Hsiao-Wu, DMD, MPH, Srinivas M. Susarla, BA, Robert R. White, DMD
Soft tissue signs are inadequate to assess pulpal anesthesia during root canal therapy (RCT). The intention of this study was to determine if a negative response to cold testing is a more effective measure to assess pulpal anesthesia compared to soft tissues signs. Using a randomized, blinded, placebo-controlled design, subjects with baseline responsiveness to cold testing were enrolled. Test subjects achieved a negative response to cold testing prior to RCT. Control subjects were given a sham cold test after demonstrating soft tissue signs. Visual analog scale determined pain level. Unadjusted results showed 12% of test subjects experienced pain during RCT compared with 38% of control subjects (N = 83, p = .004, power = 84%). Multiple logistic regression controlled for confounders and effect modifiers, OR = .20 (p = .01). Subjects who achieved a negative response to the cold test were approximately 80% less likely to experience pain during RCT compared to subjects with soft tissue signs of anesthesia alone.
Evaluation of Efficacy of a New Custom-Made Pulse Oximeter Dental Probe in Comparison With the Electrical and Thermal Tests for Assessing Pulp Vitality
Velayutham Gopikrishna, MDS, Kush Tinagupta, MDS, Deivanayagam Kandaswamy, MDS
Pulse oximetry is a noninvasive method of measuring vascular health by evaluating oxygen saturation. This study evaluated the efficacy of a new custom-made pulse oximeter dental probe in comparison with the electrical and thermal tests for assessing pulp vitality. Sensitivity, specificity, negative predictive value, and positive predictive value for each test were calculated by comparing the test results with the actual pulpal status, as evaluated by direct visual inspection. The sensitivity of the pulse oximeter was found to be 1.00, as compared to 0.81 with the cold test and 0.71 with the electrical test. The specificity of the pulse oximeter was 0.95, as compared to 0.92 with the cold and electrical pulp tests. Thus, the custom-made pulse oximeter dental probe is an effective, accurate, and objective method of evaluating pulp vitality.
Clinical, Radiographic, and Histopathologic Evaluation of Nd:YAG Laser Pulpotomy on Human Primary Teeth
Mesut Enes Odabaş, PhD, Haluk Bodur, PhD, Emre Barιş (Research Assistant), Cem Demir (Research Assistant)
The purpose of this study was to compare clinical, radiographic, and histopathologic effects of Nd:YAG laser pulpotomy to formocresol pulpotomy on human primary teeth. Patients with at least two vital primary molar teeth that required pulpotomy, because of pulpal exposure to caries, were selected for this study. After hemorrhage control, complete hemostasis into the canal orifice was achieved by exposure to Nd:YAG laser (1064 nm) and an He-Ne laser (the aiming beam of the Nd:YAG laser) in noncontact mode at 2 W, 20 Hz, 100 mJ, or was achieved by applying 1:5 dilution of formocresol. Forty-two teeth in two groups were to be followed up clinically and radiographic at 1, 3, 6, 9, and 12 months. Eighteen teeth planned for serial extractions were selected for histopathologic study. The teeth were extracted at 7 and 60 days. The teeth in the laser group had a clinical success rate of 85.71% and a radiographic success rate 71.42% at 12 months. The teeth in the formocresol group had a clinical and radiographic success rate of 90.47% at 12 months. There were no statistically significant differences between laser and formocresol group with regard to both clinical and radiographic success rates. There was a statistically significant difference between 7- and 60-day laser groups with regard to inflammatory cell response criteria. Dentin bridge was absent in all samples. No stained bacteria were observed in any of these samples. In conclusion, Nd:YAG laser may be considered as an alternative to formocresol for pulpotomies in primary teeth.
Topographical, Diametral, and Quantitative Analysis of Dentin Tubules in the Root Canals of Human and Bovine Teeth
Carlos H.R. Camargo, MSD, PhD, Mariana Siviero, DDS, Samira E. Afonso Camargo, MSD, Simone H.G. de Oliveira, MSD, PhD, Cláudio A.T. Carvalho, MSD, PhD, Márcia C. Valera, MSD, PhD
The aim of this study was to evaluate the number and the diameter of dentin tubules in root canals, in the cervical, middle, and apical thirds, of human and bovine teeth. Twenty-four single-rooted, human premolars were divided into four groups (n = 6): GH1, 10 to 15 years; GH2, 16 to 30 years; GH3, 31 to 45 years; and GH4, 46 to 80 years; and 24 bovine incisors were divided into four groups (n = 6): GB1, central; GB2, lateral first; GB3, lateral second; and GB4, lateral third. The crowns were removed from the specimens, which were then debrided, sectioned longitudinally in the vestibular-lingual direction, and submitted to ultrasonic cleaning. Scanning electron microscopic evaluations were made with 1,000× and 5,000× magnification. According to the root thirds, statistically significant differences were found both for the number and the diameter of dentin tubules, with the cervical third presenting the highest mean values for both specimen types. As regards the number of dentin tubules, it was observed that the bovine specimens presented a significantly higher mean value than the human specimens; this difference was not observed when the diameters of the two types were compared.
Personality Traits of Endodontic Residents Indicate Potential for Becoming Endodontic Faculty
Paula N. O’Neill, MEd, EdD, Timothy A. Svec, DDS, MS, John R. Ludington, DDS, MSD, John A. Suchina, DDS, MS
Dental schools across America are challenged by the shortage of qualified faculty to fill vacant positions. This project, conducted through survey methodology, focused on obtaining a basic understanding of the personality types that seek out and maintain positions as full-time endodontic educators and compared those educators with endodontic residents to define similarities and differences that could lead to strategies to recruit those residents into academic endodontic education to assist in alleviating the faculty shortage in dentistry. All full-time endodontic faculty and residents were invited to participate. The Myers Briggs type indicator form M was administered electronically to faculty and postgraduates/residents. A 38.8% faculty and 21.3% resident response rate was achieved. Survey results were analyzed by using description statistics and chi-square tests. Results of the study indicate that there are parallel personality preferences of residents and faculty resulting in recommendations of early identification of academic interest, structured mentoring, faculty development of residents, and the implementation of debt-reduction strategies to ease entry into academic dentistry.
The Role of Cyclooxygenase-2 (COX-2) in Inflammatory Bone Resorption
David Coon, DDS, Ajay Gulati, BDS, MSc, Cameron Cowan, BS, Jianing He, DMD, PhD
Prostaglandin E2 (PGE2) is an important inflammatory mediator that plays an essential role in the development and progression of periradicular diseases. Cyclooxygenase-2 (COX-2) is the inducible enzyme responsible for increased PGE2 levels during inflammation and other pathologic processes. The purpose of this study was to determine the role of COX-2-mediated PGE2 synthesis in osteoclast formation in response to endodontic pathogens and materials. Primary osteoblast cultures and osteoclast cultures were prepared from COX-2 knockout (K/O) and wild-type (WT) littermates. These cultured cells were exposed to lipopolysaccharide (LPS) or root canal obturation materials including gutta-percha (GP), Resilon (RS), mineral trioxide aggregates (MTAs), and AH Plus (AH+). Osteoclast formation was evaluated using tartrate-resistant acid phosphatase (TRAP) staining. The expression of receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG) was determined by real-time polymerase chain reaction (PCR) analysis. It was found that in both WT and K/O cultures, treatment with LPS led to a marked increase in osteoclast formation. The number of osteoclasts formed was significantly lower in K/O cultures compared to WT cultures. Exposure to endodontic materials did not lead to any significant osteoclast formation. LPS and endodontic materials caused a decrease in both RANKL and OPG expression in WT cells. In K/O cells, the baseline levels of RANKL and OPG expression were dramatically decreased compared to the WT cells. In conclusion, COX-2-mediated PGE2 expression is required for LPS-induced inflammatory bone resorption and maintaining the baseline level of RANKL and OPG expression. LPS-induced osteoclast formation may be independent of the RANKL pathway.
Effects of a Bacterial Lipid Byproduct on Human Pulp Fibroblasts In Vitro
Yung-Chuan Ho, PhD, Yu-Chao Chang, DDS, MS, PhD
Butyrate, a short chain fatty acid, is a metabolic lipid byproduct of various root canal pathogens, such as Porphyromonas endodontalis. However, little is known about the effects of butyrate on cultured human pulp fibroblasts. H33258 fluorescence, flow cytometry, and protein synthesis assays were used to investigate the pathobiologic effects of butyrate on cultured human pulp fibroblasts. Butyrate exhibited cytotoxic effects on human pulp fibroblasts in a concentration-dependent manner (p < 0.05). The addition of butyrate resulted in G2/M phase arrest (p < 0.05). Butyrate also inhibited protein synthesis in a dose-dependent manner (p < 0.05). To determine whether glutathione (GSH) levels were important in the cytotoxicity of butyrate, we pretreated cells with the GSH precursor, 2-oxothiazolidine-4-carboxylic acid (OTZ), to boost thiol levels, or buthionine sulfoximine (BSO) to deplete GSH. The addition of OTZ acted as a protective effect on the butyrate-induced cytotoxicity (p < 0.05). In contrast, the addition of BSO enhanced the butyrate-induced cytotoxicity (p < 0.05). These results indicate that butyrate is cytotoxic to human pulp fibroblasts by inhibiting cell growth, cell-cycle kinetics, and protein synthesis. These inhibitory effects were associated with intracellular GSH levels.
Effect of Prion Decontamination Protocols on Nickel-Titanium Rotary Surfaces
David Sonntag, DMD⁎, Ove A. Peters, PD, DMD, MS, FICD†
Decontamination of instruments is a prerequisite for their potential reuse but may affect surface integrity. Hence, the effect of prion removal protocols on 7 brands of nickel-titanium files was investigated. Baseline debris scores were determined under magnification after staining with van Gieson’s solution. After shaping root canals in vitro, rotaries were mechanically and ultrasonically cleaned followed by immersion for 24 hours in 2 M sodium hydroxide (NaOH), 6 M CH5N3, or 3% sodium hypochlorite (NaOCl); control files were stored dry. After sterilization, files were again stained and evaluated. Two of seven file brands demonstrated significantly higher baseline debris scores compared to final scores. Uniformly, debris could not be completely removed; there were no significant differences among groups. After immersion in NaOCl, 27.8% of instruments showed corrosion; however, no deterioration after immersion in the other solutions was found in the other groups. Regarding corrosion, no significant difference was found between brands. Based on these findings, single use of nickel-titanium rotaries appears beneficial.
Effect of Mineral Trioxide Aggregate Cements on Transforming Growth Factor β1 and Bone Morphogenetic Protein Production by Human Fibroblasts In Vitro
Gunseli Guven, DDS, PhD, Zafer C. Cehreli, DDS, PhD, Ali Ural, MD, Muhittin A. Serdar, MD, Feridun Basak, DDS, PhD
The aim of this study was to evaluate and compare the effects of two commercial mineral trioxide aggregate (MTA) cements (ProRoot MTA and MTA Angelus) on transforming growth factor (TGF)-β1 and bone morphogenetic protein (BMP)-2 levels produced by cultured human gingival fibroblasts (HGFs). Human gingival tissues were obtained from individuals with healthy periodontium. HGFs were grown at 37°C in humidified atmosphere of 5% CO2 in Dulbecco’s modified Eagle’s medium, supplemented with 10% fetal calf serum, penicillin, and streptomycin. After 24 and 72 hours of exposure to the MTA products, HGF viability was determined by using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl tetrazolium bromide assay. TGF-β1 and BMP-2 levels in cell-free culture media were determined by enzyme-linked immunosorbent assay. Cell viability of the test groups was significantly lower than that of control at 24 and 72 hours (p < 0.05) but showed an increase at 72 hours (p < 0.05). Both test groups showed increased TGF β-1 levels at 72 hours (p < 0.05), whereas the MTA Angelus group displayed higher TGF β-1 levels than control and ProRoot MTA groups at 24 and 72 hours (p < 0.05). At 24 hours, BMP-2 levels of the ProRoot group were significantly higher than that of MTA Angelus (p < 0.05). Both test materials increased the BMP-2 levels within time (p < 0.05) and displayed similar levels at 72 hours (p > 0.05). These results suggest that both MTA products are capable of stimulating HGF to produce BMP-2, whereas the stimulatory effect for TGF β-1 is material dependent.
Cytotoxicity of DP-Bioglass Paste Used for Treatment of Dentin Hypersensitivity
Tien-Chun Kuo, DDS, MS, Bor-Shiunn Lee, DDS, MS, PhD, Shu-Han Kang, DDS, MS, Feng-Huei Lin, BS, MS, PhD, Chun-Pin Lin, DDS MS, PhD
DP-bioglass mixed with 30% phosphoric acid has been suggested to treat dentin hypersensitivity because the material is able to produce homogeneous occlusion of exposed dentinal tubules and is able to provide a sealing depth of up to 60 μm. The purpose of this study was to investigate the relative cytotoxic effect of the DP-bioglass paste, intermediate restorative material (IRM; DeTrey, Dentsply, Germany), and commercial desensitizing agent (Abmindent; Abmin Technologies Ltd, Turku, Finland) on human dental pulp cells by using a transwell insert model and a dentin-disc model. Cell viability was measured by means of a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The results of this study indicated that cell viability for the DP-bioglass paste did not differ significantly from those of the IRM or Abmindent in the transwell insert model. In addition, MTT results of DP-bioglass paste were similar to the control group in the dentin-disc model. The results indicated that DP-bioglass paste was a highly biocompatible material and could potentially serve as an effective material for treatment of dentin hypersensitivity.
Time-Course Diffusion of Hydrogen Peroxide Through Human Dentin: Clinical Significance for Young Tooth Internal Bleaching
Jean Camps, DCD, PhD, Hélène de Franceschi, DCD, Fatiha Idir, DCD, Christelle Roland, DCD, Imad About, MS, PhD
The purpose of this study was to record the time-course diffusion of hydrogen peroxide through human dentin from a peroxide carbamide gel designed for the walking bleach technique in order to determine its optimal renewal time. It was considered that the optimal renewal rate corresponded to the time necessary to achieve 80% of the maximal diffusion because a much longer time does not involve further significant diffusion. Thirty-six freshly extracted human premolars were used for this study. Eighteen were extracted for orthodontic reasons on patients under 20 years old (young-teeth group). Eighteen were extracted for periodontal reasons on patients between 40 and 60 years old (old-teeth group). The teeth were endodontically treated, and a flat defect was created at the enamel-cementum junction. The teeth were suspended in vials containing water, and the access cavities were filled with 20 μL of 20% hydrogen peroxide gel. The amount of diffusing hydrogen peroxide was assessed at 1 hour, 24 hours, 48 hours, and 120 hours. The diffusive flux and the maximal diffusion were calculated as well as the optimal renewal time. Hydrogen peroxide diffusion through young teeth lasted 352 hours but lasted 291 hours through old teeth. Diffusive flux and maximal diffusion were higher through young teeth than through old teeth. The optimal renewal time for young teeth was 33 hours and for old teeth was 18 hours.
Effect of Intracoronal Bleaching Agents on Dentin Microhardness
Daniel Pinto de Oliveira, DDS, MSc⁎‡, Erica Cappelletto Nogueira Teixeira, DDS, MSc†, Caio Cezar Randi Ferraz, DDS, MSc, PhD‡, Fabricio B. Teixeira, DDS, MSc, PhD
The purpose of this in vitro study was to compare the effect of intracoronal bleaching agents associated or unassociated with chlorhexidine gel on dentin microhardness. Sixty human maxillary incisor crowns were divided into six groups, and bleaching agents were sealed into the pulp chambers as follows: sodium perborate + water (SPW), sodium perborate + 2% chlorhexidine gel (SP + CHX), sodium perborate + 30% hydrogen peroxide solution (SP + HP), 37% carbamide peroxide gel (CP), 37% carbamide peroxide gel + 2% chlorhexidine gel (CP+CHX), and water (W). After the bleaching procedure, microhardness testing was carried out on the dentin surface at three different levels: inner, middle, and outer dentin. The greatest reduction in microhardness was observed for the SP + HP group. No differences were observed between the SPW and SP + CHX group. The 2% chlorhexidine gel did not adversely affect dentin microhardness when associated with the tested bleaching agents. CHX might be considered as an antimicrobial vehicle during intracoronal bleaching.
Metrologic Evaluation of the Surface of White MTA After the Use of Two Endodontic Irrigants
Jack B. Smith, DMD, Robert J. Loushine, DDS, R. Norman Weller, DMD, MS, Frederick A. Rueggeberg, DDS, MS, Gary M. Whitford, DMD, PhD, David H. Pashley, DMD, PhD, Franklin R. Tay, BDSc(Hons), PhD
This study examined the effects of calcium-depleting endodontic irrigants, ethylenediamine tetra-acetic acid (EDTA) and BioPure MTAD, on the dissolution, surface characteristics, and ultrastructural characteristics of white mineral trioxide aggregate (MTA). The latter was mixed in a 0.35 water–cement ratio, condensed into cylindrical wells created in Plexiglas platforms, and allowed to harden completely before initial treatment with 1.3% NaOCl and final treatments with either 17% EDTA for 5 minutes, or BioPure MTAD for 1, 3, or 5 minutes. Analysis of the mean depths of material removed using three-dimensional profilometry revealed significantly more material removed by BioPure MTAD. Although these minor depth changes (<10 μm) are unlikely to cause clinical concern, the BioPure MTAD-treated MTA surfaces exhibited higher surface roughness and with more calcium extracted when compared with EDTA treatment. Decomposition of particle-binding hydration phases by acid corrosion raises potential concern on the strength and sealing properties of MTA-repaired perforations following final irrigation by BioPure MTAD.
Quality of Molar Root Canal Fillings Performed With the Lateral Compaction and the Single-Cone Technique
Preben Hörsted-Bindslev, DDS, Mette A. Andersen, DDS, Michaela F. Jensen, DDS, Julie H. Nilsson, DDS, Ann Wenzel, DDS, PhD
The aim was to compare the quality of root canal fillings performed with the single-cone and lateral compaction technique. Thirty-six canals in extracted molars were filled with ISO-standardized gutta-percha points, .02 taper, by using the lateral compaction technique; 38 were filled with one gutta-percha point, .04 taper, by using the single-cone technique. Each root canal was radiographed in the bucco-oral (BO) and the mesiodistal projection (MD). A root was sufficiently filled when three of four observers had assessed it so. There was no significant impact of the filling technique on the quality (logistic regression analysis, p > 0.4). There was a significant impact of the canal type, the mandibular distal canal having a higher chance for a sufficient root filling than the mandibular mesial canal in projection BO (p = .003), but both the mandibular distal (p = 0.001) and the maxillary palatal canals (p = 0.014) had a lower chance for a sufficient filling in projection MD.
Effect of EDTA with and without Surfactants or Ultrasonics on Removal of Smear Layer
Jeen-Nee Lui, BDS, MDS, MRD, Hong-Guan Kuah, BDS, MDS, MRD, Nah-Nah Chen, BDS, MDS, MS
This study compared the in vitro efficacy of Smear Clear (Sybron Endo, CA), a 17% ethylenediaminetetraacetic acid (EDTA) solution with surfactants, to 17% EDTA, with and without the use of ultrasonics, in removal of the smear layer. Seventy-five extracted teeth, randomly distributed into 5 test groups, were prepared by using ProFile rotary instruments (Dentsply Maillefer, Ballaigues, Switzerland) and subjected to different final irrigating regimes; group A, 1% sodium hypochlorite; group B, 17% EDTA; group C, 17% EDTA with ultrasonics; group D, Smear Clear; and group E, Smear Clear with ultrasonics. Samples were examined under the scanning electron microscope and scored for debris and smear layer removal. Statistical analysis showed that groups D and E did not perform significantly better than groups B and C. Group C performed significantly better than group B. Addition of surfactants to EDTA in Smear Clear did not result in better smear layer removal. The use of ultrasonics with 17% EDTA improved smear layer removal.
Influence of Embedding Media on the Assessment of Electronic Apex Locators
Járcio V. Baldi, DDS, MSc, Fausto R. Victorino, DDS, MSc, Ricardo A. Bernardes, DDS, MS, Ivaldo G. de Moraes, DDS, MSc, PhD, Clóvis M. Bramante, DDS, MSc, PhD, Roberto B. Garcia, DDS, MSc, PhD, Norberti Bernardineli, DDS, MSc, PhD
Third-generation electronic apex locators for root canal length determination are very reliable and are not subject to interference from the contents of the canals. This study compared the effectiveness of different embedding media for in vitro assessment of electronic apex locators. The tooth lengths of 30 extracted human mandibular central incisors were measured by introducing a size 15 K-file fitted with a silicone stop into the canal until its tip appeared through the apical foramen; the distance between the tip and stop was measured. The teeth were placed in cylindrical polyethylene tubes filled with different embedding media (1% agar, gelatin, alginate, saline, and flower sponge soaked in saline), and electronic reading was performed with the Root ZX™® device. Data were statistically assessed by the analysis of variance (ANOVA) and Tukey tests at a significance level of 5%. Despite the lack of statistically significant difference among the media, the flower sponge was the only medium in which the filesurpassed the apex in some measurements.
Fracture Resistance of Simulated Immature Teeth Filled with Resilon, Gutta-Percha, or Composite
Kim L. Wilkinson, DDS, Thomas J. Beeson, DDS, Timothy C. Kirkpatrick, DDS
The purpose of this study was to evaluate the fracture resistance gained by filling root canals of simulated immature teeth with either Resilon, gutta-percha, a self-curing flowable composite resin (BisFil 2B), or a self-curing hybrid composite resin (BisFil II). Seventy-two sheep incisors were divided into six groups of 12 teeth each. Negative controls received no treatment. Teeth in all other groups were prepared until a size 120 LightSpeed LSX instrument could be passed out the apex. After apical placement of a mineral trioxide aggregate (MTA) barrier, the canals were filled with their respective test material to the facial CEJ. The positive control canals were left unfilled. The access openings (including positive controls) were restored with BisFil II. Each root was horizontally fractured through the test material using an Instron. The mean peak loads to fracture were recorded. The hybrid composite resin (BisFil II) was the only material significantly more fracture resistant than positive controls (p < 0.017).
Evaluation of Apical Cavity Preparation With a New Type of Ultrasonic Diamond Tip
Ricardo A. Bernardes, DDS, MS, Ivaldo G. de Moraes, DDS, MS, PhD, Roberto B. Garcia, DDS, MS, PhD, Norberti Bernardineli, DDS, MS, PhD, Jarcio V. Baldi, DDS, MS, Fausto R. Victorino, DDS, MS, Bruno C. Vasconcelos, DDS, MS, Marco A.H. Duarte, DDS, MS, PhD, Clovis M. Bramante, DDS, MS, PhD
This study evaluated the time, occurrence of fracture, and quality of apical cavity preparation with three different ultrasonic diamond tips: Satelec, Trinity, and a new type, CVD (chemical vapor deposition), using scanning electron microscopy (SEM) analysis. Thirty human single-rooted premolars were selected, submitted to apicectomy, and prepared with ultrasonic tips; impressions were then obtained. The presence of fractures was evaluated on the impressions, and the quality of preparation was evaluated by SEM analysis of teeth and scoring by two examiners. The group prepared with the CVD tips exhibited the shorter preparation time and did not present fractures. There was no statistically significant difference in the quality of preparation for the three tips. The three brands of ultrasonic tips produced adequate grinding without altering the morphology of the apical foramen.
Dentigerous Cyst Associated with a Formocresol Pulpotomized Deciduous Molar
Eugenia Asián-González, PhD, MD, DDS, Manuela Pereira-Maestre, MD, DDS†, Dolores Conde-Fernández, PhD, MD, DDS, Ignacio Vilchez, DDS, Juan José Segura-Egea, PhD, MD, DDS, José Luis Gutiérrez-Pérez, PhD, MD, DDS
This report presents a case of dentigerous cyst associated with a formocresol pulpotomized deciduous molar detected during routine examination. Dentigerous cyst is an epithelial-lined developmental cavity that encloses the crown of an unerupted tooth at the cementoenamel junction. The present case describes a 9-year-old girl sent to the dental clinic by her dentist, who had accidentally discovered in the panoramic radiograph a single, unilocular, well-defined, radiolucent area enclosing the second left unerupted mandibular premolar. The second left primary molar had been pulpotomized 2 years before and buccal swelling without redness occurred near the tooth, evidencing bone expansion. Surgical treatment was carried out, the tooth was extracted, and a cystectomy was performed under local anesthesia in the dental office. The histological study confirmed the suspected diagnosis of dentigerous cyst. The relation between pulpotomy and dentigerous cysts is discussed.
Evaluation of Chronic Periapical Lesions by Digital Subtraction Radiography by Using Adobe Photoshop CS: A Technical Report
Fabiola B. Carvalho, DDS, MSc, Marcelo Gonçalves, DDS, MSc, PhD, Mário Tanomaru-Filho, DDS, MSc, PhD
The purpose of this study was to describe a new technique by using Adobe Photoshop CS (San Jose, CA) image-analysis software to evaluate the radiographic changes of chronic periapical lesions after root canal treatment by digital subtraction radiography. Thirteen upper anterior human teeth with pulp necrosis and radiographic image of chronic periapical lesion were endodontically treated and radiographed 0, 2, 4, and 6 months after root canal treatment by using a film holder. The radiographic films were automatically developed and digitized. The radiographic images taken 0, 2, 4, and 6 months after root canal therapy were submitted to digital subtraction in pairs (0 and 2 months, 2 and 4 months, and 4 and 6 months) choosing “image,” “calculation,” “subtract,” and “new document” tools from Adobe Photoshop CS image-analysis software toolbar. The resulting images showed areas of periapical healing in all cases. According to this methodology, the healing or expansion of periapical lesions can be evaluated by means of digital subtraction radiography by using Adobe Photoshop CS software.