Ultrasonics in Endodontics: A Review of the Literature
Gianluca Plotino, DDS, Cornelis H. Pameijer, DMD, DSc, PhD, Nicola Maria Grande, DDS, Francesco Somma, MD, DDS
During the past few decades endodontic treatment has benefited from the development of new techniques and equipment, which have improved outcome and predictability. Important attributes such as the operating microscope and ultrasonics (US) have found indispensable applications in a number of dental procedures in periodontology, to a much lesser extent in restorative dentistry, while being very prominently used in endodontics. US in endodontics has enhanced the quality of treatment and represents an important adjunct in the treatment of difficult cases. Since its introduction, US has become increasingly more useful in applications such as gaining access to canal openings, cleaning and shaping, obturation of root canals, removal of intracanal materials and obstructions, and endodontic surgery. This comprehensive review of the literature aims at presenting the numerous uses of US in clinical endodontics and emphasizes the broad applications in a modern-day endodontic practice.
Effect of Smear Layer on Sealing Ability of Canal Obturation: A Systematic Review and Meta-analysis
Arash Shahravan, DDS, MSc, Ali-Akbar Haghdoost, MD, PhD, Alireza Adl, DDS, MSc, Hessam Rahimi, DDS, Fahimeh Shadifar, DDS
The purpose of this systematic review was to determine whether smear layer removal reduces leakage of obturated human teeth in vitro. PubMed was searched for articles published between 1975 and 2005, and results were categorized based on the method of leakage test. Among 26 eligible papers with 65 comparisons, 53.8% of the comparisons reported no significant difference, 41.5% reported a difference in favor of removing the smear layer, and 4.7% reported a difference in favor of keeping it; differences were significant (p < 0.001). Of the 65 comparisons, 44 used the dye leakage test for evaluation. The combined effect in this group showed smear layer removal decreases dye leakage (z-score = 0.37, z = 2.31, p = 0.021). According to meta-regression, obturation type, test site and duration, sealer and dye, and publication year had no effect on the results. Under the conditions of these in vitro leakage studies, it is concluded that smear layer removal improves the fluid-tight seal of the root canal system whereas other factors such as the obturation technique or the sealer, did not produce significant effects.
Outcome of Root Canal Obturation by Warm Gutta-Percha versus Cold Lateral Condensation: A Meta-analysis
Li Peng, DDS, MS, Ling Ye, DDS, PhD, Hong Tan, DDS, Xuedong Zhou, DDS, PhD
The purpose of this study was to evaluate clinical outcome differences of root canal obturation by warm gutta-percha (GP) or cold lateral condensation (CLC) through a systematic review and meta-analysis. There were 10 clinical studies evaluated. Postoperative pain, long-term outcomes, obturation quality, and overextension were the characteristics investigated. The results suggest that the two obturation techniques are not significantly different except in overextention. The relative risk (RR) value of warm GP versus CLC and 95% confidence interval (CI) of the first three criteria were 1.10 (0.71, 1.71), 0.78 (0.58, 1.05), and 1.31 (0.98, 1.76), respectively. Overextension was more likely to occur in the warm GP obturation group in comparison with the CLC group. The RR value and 95% CI were 1.98 (1.33, 2.93). In conclusion, warm GP obturation demonstrated a higher rate of overextension than CLC. Postoperative pain prevalence, long-term outcomes, and obturation quality were similar between the two groups.
Prion Protein (PrP) in Human Teeth: An Unprecedented Pointer to PrP’s Function
Kurt Schneider, Yüksel Korkmaz, DDS, Klaus Addicks, MD, PhD, Hermann Lang, DDS, PhD, Wolfgang H.-M. Raab, DDS, PhD
Although prion protein’s (PrP) involvement in transmission of degenerative neurological diseases has been subjected to considerable scrutiny, its physiological role is still obscure. The distribution of PrP in dental tissues was investigated using three different methods: immunohistochemistry, cell culture, and scanning electron microscopy. PrP knockout mice were found to have marked anomalies in dentin structure. In human teeth, cementoblasts and odontoblasts showed prominent staining for PrP at levels comparable to those of nerve fibers. Epithelial rests of Malassez, which are remnants of a cell type formerly forming enamel, were also positive. Thus, all PrP-positive cells in human dentition are in some way involved in calcified tissue formation. This suggests a previously undetected function of prion protein in healthy vertebrates as evidenced by an obvious phenotype in PrP knockout mice. Periodontal and pulpal tissue exposed by disease or trauma might represent a clinically relevant entry point for prions incorporated orally and thus a possible mode of infection.
Bacterial Quantification in Teeth with Apical Periodontitis Related to Instrumentation and Different Intracanal Medications: A Randomized Clinical Trial
Aldo Manzur, DDS, MSc, Ana Maria González, QFB, MSc, Amaury Pozos, DDS, PhD†, Daniel Silva-Herzog, DDS, Shimon Friedman, DMD
The antibacterial efficacy of intracanal medication with calcium hydroxide [Ca(OH)2], 2% chlorhexidine gel (CHX), and a combination of both [Ca(OH) 2/CHX] was assessed in teeth with chronic apical periodontitis. Thirty-three canals were instrumented, randomly divided into three groups, and medicated with either Ca(OH) 2, CHX, or Ca(OH) 2/CHX. Bacteriological samples obtained from the operative field and the root canals before (S1) and after instrumentation (S2) in the first treatment session, and after medication (S3) in the second session 1 week later, were assessed for bacterial growth, observed by turbidity and in agar plates, and viable colony-forming unit (CFU) counts. Bacterial growth and CFU counts decreased significantly from S1 to S2 (Mann–Whitney, p < 0.05). Differences in growth and counts between S2 to S3 were not statistically significant for all three intracanal medication groups. It was concluded that the antibacterial efficacy of Ca(OH) 2, CHX, and Ca(OH) 2/CHX was comparable.
Orthodontic Root Resorption of Endodontically Treated Teeth
Tarso Esteves, DDS, Adilson Luiz Ramos, PhD, Calliandra Moura Pereira, DDS, Mirian Marubayashi Hidalgo, PhD
The purpose of this study was to evaluate, radiographically, whether there is similarity in the apical root resorption found in endodontically treated teeth and untreated teeth when they are submitted to orthodontic treatment. From 2,500 treatment records examined, 16 patients were selected who had a maxillary central incisor treated endodontically before initiation of the orthodontic movement, and a vital homologous tooth (for control). Measurements were made by comparing the periapical radiographs taken before and after the orthodontic treatment. There was no statistically significant difference (p > 0.05) in apical root resorption found in the endodontically treated teeth compared to the group of vital teeth.
Clinical and Radiographic Assessment of Various Predictors for Healing Outcome 1 Year After Periapical Surgery
Thomas von Arx, PD, DMD, Simon Storgård Jensen, DO, Stefan Hänni, DMD
This clinical study prospectively evaluated the influence of various predictors on healing outcome 1 year after periapical surgery. The study cohort included 194 teeth in an equal number of patients. Three teeth were lost for the follow-up (1.5% drop-out rate). Clinical and radiographic measures were used to determine the healing outcome. For statistical analysis, results were dichotomized (healed versus nonhealed). The overall success rate was 83.8% (healed cases). The only individual predictors to prove significant for the outcome were pain at initial examination (p = 0.030) and other clinical signs or symptoms at initial examination (p = 0.042), meaning that such teeth had lower healing rates 1 year after periapical surgery compared with teeth without such signs or symptoms. Logistic regression revealed that pain at initial examination (odds ratio = 2.59, confidence interval = 1.2-5.6, p = 0.04) was the only predictor reaching significance. Several predictors almost reached statistical significance: lesion size (p = 0.06), retrofilling material (p = 0.06), and postoperative healing course (p = 0.06).
Morphological Measurements of Anatomic Landmarks in Pulp Chambers of Human Anterior Teeth
Myong M. Lee, DDS, Brian J. Rasimick, BS, Aura M. Turner, BS, Rinal P. Shah, BS, Barry Lee Musikant, DMD, Allan S. Deutsch, DMD
This in vitro study measured key morphological features of pulp chambers in anterior teeth and tested the hypothesis that the distance from the lingual surface (midpoint from the cusp tip to the lingual CEJ) to the pulp chamber (the midpoint from the buccal to the lingual CEJ) was similar for different tooth types. Extracted human teeth were sorted and 100 samples of each of the following tooth types were chosen: maxillary central incisor (UCI), lateral incisor (ULI), and canine (UC), as well as mandibular central incisor (LCI), lateral incisor (LLI), and canine (LC). All teeth were digitally radiographed on a 1-mm X-ray grid. The mean values of measurement C, the distance from the lingual surface to the pulp chamber, varied significantly between tooth types (p < 0.001). The mean values and SNK rankings were as follows: LC (5.9 ± 0.5 mm) > UC (5.5 ± 0.5) = UCI (5.4 ± 0.4) > ULI (5.0 ± 0.4) > LLI (4.8 ± 0.5) > LCI (4.4 ± 0.4).
Kinetic Study of Immunohistochemical Colocalization of Antigen-presenting Cells and Nerve Fibers in Rat Periapical Lesions
Guangyan Yang, DDS, PhD, Nobuyuki Kawashima, DDS, PhD, Tomoatsu Kaneko, DDS, PhD, Noriyuki Suzuki, DDS, PhD, Takashi Okiji, DDS, PhD, Hideaki Suda, DDS, PhD
Immune and nervous systems play key roles in periapical pathosis; however, their spatial associations, which may be a prerequisite for paracrine interactions in the progression of periapical lesions, remain to be examined. In this study we examined the distribution and frequency of spatial associations between major histocompatibility complex class II molecule-expressing antigen-presenting cells (APCs) and protein gene product 9.5-immunoreactive nerve fibers in experimentally induced rat periapical lesions using double-immunofluorescence staining and confocal laser scanning microscopy. When active lesion expansion started, macrophage-like APCs frequently associated with nerve fibers around the apex. When the lesions were starting to stabilize, however, close associations between APCs with dendritic morphology and nerve fibers were found mostly in the periphery of lesions. CD86+ mature dendritic cells were also observed in this area. These findings suggest that functional interactions between APCs and nerve fibers may play some roles in the development of self-defense reactions in periapical lesions.
Involvement of Inducible Nitric Oxide Synthase and Receptor for Advanced Glycation End Products in Periapical Granulomas
Shinji Hama, DDS, Osamu Takeichi, DDS, PhD, Ichiro Saito, DDS, PhD, Koichi Ito, DDS, PhD
We examined the presence of the receptor for advanced glycation end products (RAGE) in periapical granulomas and analyzed the interaction between RAGE and inducible nitric oxide synthase (iNOS) to elucidate inflammatory reaction mechanisms. Periapical lesions were surgically removed from 37 patients with chronic periapical periodontitis and halved. Paraffin sections were prepared from half of each lesion and stained with hematoxylin and eosin, whereas cryostat sections were prepared from the other half. Based on the histological evaluation, 33 of the lesions were diagnosed as periapical granulomas. These were examined by immunohistochemistry using serial cryostat sections probed with anti-human iNOS or RAGE antibodies. Macrophages, lymphocytes, and endothelial cells expressed RAGE and these cell types, in addition to plasma cells, exhibited anti-iNOS immunoreactivity. Serial cryostat sections demonstrated the infiltration of RAGE-expressing cells around iNOS-producing cells, suggesting that these molecules may be important in the tissue injury associated with periapical periodontitis.
Nitric Oxide Synthase and PGE2 Reciprocal Interactions in Rat Dental Pulp: Cholinoceptor Modulation
Enri Borda, César Furlan, Betina Orman, Silvia Reina, Leonor Sterin-Borda
In this study we determined the effect of cholinoceptor agonist pilocarpine on the stimulation of nitric oxide synthase (NOS) and on prostaglandin E2 (PGE2) generation upon rat dental pulp. By reverse transcriptase/polymerase chain reaction (RT-PCR) we identified several products corresponding to m1, m2, m3, and m4 muscarinic acetylcholine receptors (mAChRs). The stimulation of M1, M2, M3, and M4 mAChRs by pilocarpine increases NOS activity and PGE2 generation. There is a correlation (correlation coefficient = 0.05) between NOS activity and PGE2 generation through the activation of phosphoinositide by phospholipase C (PLC), phospholipase A2 (PLA2), and cyclooxygenase 1 (COX-1). Exogenous PGE2 restored NOS activity inhibited by indomenthacin (INDO), whereas nitric oxide (NO) donor restored PGE2 generation inhibited by NG-methyl-L-arginine acetate salt (L-NMMA). These data indicate that both NO and PGE2 interact with their own respective biosynthetic pathways modulating NOS and COX activities. Results could contribute to understanding the involvement of NO and PGE2 in healthy dental pulp given that cellular signals through the parasympathetic system modulate the function of the dentin–pulp complex.
Periapical Surgery Using CAD/CAM Guidance: Preclinical Results
Harold M. Pinsky, DDS, Guillaume Champleboux, PhD, David P. Sarment, DDS, MS
Apicoectomy is a surgical procedure requiring precise planning and access to locate apices and avoid vital anatomic structures. Traditional methods limit treatment because they rely on two-dimensional radiography and corrective actions during surgery. Surgical guidance, which uses computed tomography and computer-aided design and computer-aided manufacturing processing, has been utilized in dentistry, but not in endodontics. Therefore, the aim of this study was to introduce periapical surgical guidance using computed tomography and computer-aided design and computer-aided manufacturing surgical guides and to compare apical access accuracy using guidance versus a conventional method. Results showed that distance from the apex was 0.79 mm (±0.33 SD) using guidance and 2.27 mm (±1.46 SD) using freehand drilling. An error greater than 3 mm occurred over 22% of the time freehand, yet never occurred with guidance. This in vitro study suggests that greater accuracy and consistency can be achieved during endodontic surgery with surgical guidance. Advantages also include presurgical visualization in three dimensions.
Effect of Endodontic Irrigants on the Shear Bond Strength of Epiphany Sealer to Dentin
Aaron J. Wachlarowicz, DDS, Anthony P. Joyce, DDS, Steven Roberts, DDS, David H. Pashley, DMD, PhD
This study examined the effects of commonly employed endodontic irrigants on Epiphany-dentin bond strengths. Smear layers were created on dentin discs obtained from human third molars. Five groups of 10 discs each were treated with one of the following: (a) water; (b) 2% chlorhexidine; (c) 6% sodium hypochlorite (NaOCl); (d) 6% NaOCl followed by EDTA and water; or (e) 1.3% NaOCl followed by MTAD. The treated surfaces were air-dried and treated with Epiphany primer. Hollow steel tubes were placed on the dentin surfaces, and Epiphany sealer was applied to dentin inside the tubes. Samples were tested for shear bond strengths after 7 days of storage. Representative specimens were examined using scanning electron microscopy. One-way ANOVA and Tukey’s test revealed significant differences among the groups (p < 0.05). Using water or chlorhexidine as an irrigant resulted in significantly lower bond strengths when compared with NaOCl, NaOCl/EDTA, or NaOCl/MTAD. Neither EDTA nor MTAD significantly improved Epiphany-dentin bond strengths when compared with NaOCl used alone.
Assessment of a Thermoplasticized Gutta-Percha Delivery System to Effectively Obturate Canals with Varying Preparation Dimensions
Chris Yelton, BA, BS, Mary P. Walker, DDS, PhD, Charles Lee, DDS, MS, James A. Dryden, DDS, MS, James C. Kulild, DDS, MS
The purpose of this study was to measure the ability of a thermoplasticized-injectable (TPI) gutta-percha (GP) delivery system to fill a prepared root canal to working length and replicate intracanal defects (coronal, middle, apical) as a function of root canal preparations with varying lateral dimensions. Three split-tooth models with 0.06 taper and different apical gauge preparations, 0.30 mm (group A), 0.40 mm (group B), and 0.50 mm (group C), were used. Obturations were evaluated using an ordinal scale (0-4) based on how much each intracanal defect was replicated. Coronal and middle defects were completely replicated 100% of the time, regardless of the preparation. However, there was a significant difference (p ≤ 0.05) between apical defect replication with more accurate replication in groups B and C. There was also a significant difference (p ≤ 0.05) in working length replication; groups A and B, respectively, exhibited 1.20 and 0.52 mm mean underfill, and 0.52 mm mean extrusion was associated with group C. These results suggest group B with a 0.40-mm apical gauge preparation might yield better intracanal defect and working length replication when using TPI GP in the clinical situation.
Push-Out Bond Strength of a New Endodontic Obturation System (Resilon/Epiphany)
Marilia M. Sly, DDS, MSD, B. Keith Moore, PhD, Jeffrey A. Platt, DDS, MS, Cecil E. Brown, DDS, MS
Endodontic sealers should demonstrate adhesive properties to dentin to reach the objectives of the obturation of the canal space and seal the canal space both apically and coronally, thus decreasing the chance of endodontic treatment failure. Adhesion to dentin with bonding to the tooth structure in the canal may provide greater resistance to tooth fracture and greater clinical longevity of an endodontically treated tooth. In this study, human single-canal canines were endodontically treated and obturated with two different endodontic obturation systems (Epiphany/Resilon system and gutta-percha/AH 26). Thirty roots (divided into two groups) were horizontally sliced for a push-out strength test, which was performed from apical to coronal in the universal testing machine. Differences in push-out bond strength between the two different material systems were obtained using repeated measures analysis of variance on ranks. Gutta-percha had significantly higher push-out bond strength than Epiphany (p < 0.0001).
Human Pulp Cells Response to Portland Cement In Vitro
Kyung-San Min, DDS, MS, Hyun-Il Kim, DDS, Hyo-Jin Park, DDS, Sung-Hee Pi, DDS, MS†, Chan-Ui Hong, DDS, PhD, Eun-Cheol Kim, DDS, PhD
The aim of this study was to investigate the cellular effects of Portland cement on cultured human pulp cells. Using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, no cytotoxicity was observed in the Portland cement group in comparison with the negative control group, whereas the glass ionomer cement, intermediate restorative material, and Dycal groups showed a survival rate of less than 40% at 12 hours. Scanning electron microscopy revealed that human pulp cells attached to the Portland cement were flat and had numerous cytoplasmic extensions. In the groups in which other materials were used, a few rounded cells were observed on the material but no living cells were observed. The expression of both osteonectin and dentin sialophosphoprotein mRNAs was induced in the Portland cement–treated group. These results suggest that Portland cement is biocompatible, allows the expression of mineralization-related genes on cultured human pulp cells, and has the potential to be used as a proper pulp-capping material.
Influence of Glass-Ionomer Cement on the Interface and Setting Reaction of Mineral Trioxide Aggregate When Used as a Furcal Repair Material Using Laser Raman Spectroscopic Analysis
Suresh Nandini, BDS, Suma Ballal, MDS, Deivanayagam Kandaswamy, MDS
The prolonged setting time of mineral trioxide aggregate (MTA) is the main disadvantage of this material. This study analyzes the influence of glass-ionomer cement on the setting of MTA using laser Raman spectroscopy (LRS). Forty hollow glass molds were taken in which MTA was placed. In Group I specimens, MTA was layered with glass-ionomer cement after 45 minutes. Similar procedures were done for Groups II and III at 4 hours and 3 days, respectively. No glass ionomer was added in Group IV, which were then considered as control samples. Each sample was scanned at various time intervals. At each time interval, the interface between MTA and glass-ionomer cement was also scanned (excluding Group IV). The spectral analysis proved that placement of glass-ionomer cement over MTA after 45 minutes did not affect its setting reaction and calcium salts may be formed in the interface of these two materials.
An Evaluation of Microbial Leakage After Using MTAD as a Final Irrigation
Jamileh Ghoddusi, Armita Rohani, Tahereh Rashed, Pari Ghaziani, Majid Akbari
Cleaning the root canal is not possible without using proper irrigation. The aim of this in vitro study was to evaluate the effect of MTAD as a final irrigant on bacterial leakage of the root canal, and its interaction with two conventional root canal sealers. We used 132 extracted human maxillary anterior teeth. The teeth were randomly divided into three experimental groups (n = 40) and two groups (n = 6) of positive and negative control. In group 1, the smear layer was not removed and irrigation was performed using 5.25% NaOCl. In group 2, the smear layer was removed using EDTA, and in group 3, the smear layer was removed using MTAD according to the clinical protocol of use. The teeth in each group were obturated with gutta-percha and AH-Plus or Rickert sealer. The coronal portion of each root was placed in contact with inoculum of Streptococcus mutans in Brain Heart Infusion (BHI) culture media. Each root tip was placed in one bottle containing sterile BHI. Mean duration of bacterial penetration in groups 2 and 3 was significantly greater than in group 1, but there was no significant difference between groups 2 and 3. According to our findings, it takes longer for bacteria to penetrate when either EDTA or MTAD is used for smear layer removal. The root canals obturated with AH Plus showed significantly longer duration of resistance to bacterial penetration than canals obturated with Rickert.
Gingival Squamous Cell Carcinoma Mimicking a Dentoalveolar Abscess: Report of a Case
Jang-Jaer Lee, DDS, MS, Shi-Jung Cheng, DDS, MS, Sze-Kwan Lin, DDS, MS, PhD, Chun-Pin Chiang, DDS, DMSc, Chuan-Hang Yu, DDS, MS, Sang-Heng Kok, DDS, PhD
Because of its close proximity to teeth and periodontium, gingival squamous cell carcinoma (SCC) can sometimes mimic tooth-related benign inflammatory conditions, resulting in misdiagnosis. In this study we report a case of gingival SCC that mimicked a dentoalveolar abscess of endodontic origin in its early presentation. The course and treatment of this case is discussed and a brief review of the literature is presented. Because many patients with gingival SCC visit dentists as their initial professional contact, it is hoped that the case can serve as a reminder for dentists to keep the possibility of carcinoma in mind when examining intraoral lesions.
Efficacy of Ultrasound and Color Power Doppler as a Monitoring Tool in the Healing of Endodontic Periapical LesionsNivedha Rajendran, MDS, Balagopal Sundaresan, MDS, MSc
This study determined the efficacy of high-resolution ultrasound and color power Doppler as a monitoring tool in the healing of periapical lesions. Five patients with a periapical lesion in the maxillary anterior teeth were chosen for this study. A preoperative ultrasound with color power Doppler was done to analyze the features of the periapical lesion. These patients were then treated by nonsurgical endodontics and followed up on a regular basis. A 6-month postoperative ultrasound and Doppler study of the same lesion was done to observe the healing of the lesion compared with the preoperative images. The ultrasound with Doppler gave inferences of bone healing in all the lesions. This study demonstrates the application of ultrasound and color power Doppler as a viable and nonhazardous tool for monitoring the healing of periapical lesions.
A Case Report of a Patient with Raynaud’s Phenomenon Undergoing Multiple Endodontic Procedures
Charles H. Rankin, BA, DMD
The pulp represents a terminal circulation. This fact, in addition to other anatomical limitations such as a large volume of pulp: blood supply ratio and the inability of pulp tissue to swell because of its dentinal confines, all may contribute to the susceptibility of the pulp to infection and necrosis. Raynaud’s disease primarily affects the terminal vasculature of the fingers, toes or nose. Is there a relationship between patients with Raynaud’s disease and the status of the terminal vasculature of their dental pulps? The presented case opens up the question and possibly makes a correlation between peripheral vascular disease and pulpal disease.