The Effect of Orthodontic Forces on Tooth Response to Electric Pulp Test

Introduction: The current study investigated the pulp response to electric pulp testing (EPT), before, upon initiation and one month after the start of orthodontic tooth movement. Methods and Materials: A total of 402 anterior teeth from 39 patients (mean age of 16.8±2.7 years) were examined in this non-controlled prospective study. The aligning forces were administered using initial NiTi archwires ligated on fixed appliances by using the MBT straight wire technique. The electrical stimulation was provided by the EPT. The EPT readings were recorded at three time points: before bonding (EPT0), immediately upon initiation (EPT1) and 1 month post-treatment (EPT2). The data were statistically analyzed by the ANOVA and Bonferroni tests (P<0.05). Results: Prior to bonding of the orthodontic brackets, the mean EPT value for all the experimental teeth was 3.42 EPT units. Upon initiation, the mean value of EPT1 for each tooth increased to 7.62 units. One month later, the mean EPT2 values dropped to 6.27 units. At this time point, 64 teeth (16%) of the experimental teeth failed to respond. The differences among EPT values at different time points were significant. There was no association between the EPT values and the location or the type of teeth. Conclusion: The physiological changes in the pulp affect the nerve fibers in the early stages of the orthodontic force application. As a result, thresholds to electrical stimulation would increase and the EPT may not initiate a response. Therefore results obtained by electrical pulp testing should be interpreted accordingly.Keywords:Electric Pulp Test; Orthodontic Treatment; Pulp Vitality

Effects of 810nm Diode Laser Irradiation on Flexural Strength of Dentin: An Invitro Study

INTRODUCTION: Thermal changes in laser assisted root canal therapy with the use of diode laser can predispose tooth structure to the fracture. This study evaluated the changes in flexural strength of dentin blocks after diode laser irradiations (810 nm).METHODS: A total of 60 dentinal blocks were prepared from freshly extracted teeth in three different thicknesses (300, 500 and 1000μm) and 20 sections in each of these thicknesses were divided randomly to the test and control groups. Samples in the test groups were irradiated at 2W power setting by scanning movement of 2mm/s of diode laser, and the controls were stored in normal saline. The flexural strength of samples was evaluated by UTM (Universal Testing Machine). Data analysis was done with the SPSS Software 11.5.RESULTS: Samples of 300μ had the lowest flexural strength (mean: 71/65 mpa) followed by 500 (116.64 mpa) and 1000μ (217.56 mpa). Statistical analyses showed that after laser irradiation, the flextural strength in the samples of 300μ was significantly lower than that in the other groups (500μ, 1000μ) (P= 0.017).CONCLUSION: Within the limits of this study, diode laser irradiation in laser assisted root canal therapy has no significant effect on flexural strength of root dentinal walls with the thickness of more than 500μ. Although in areas with critical dentinal width (≤300μ), this setting can jeopardize root micromechanical properties and predispose tooth to the root fracture

Effect of Premedication with Indomethacin and Ibuprofen on Postoperative Endodontic Pain: A Clinical Trial

Introduction: Post-endodontic pain is one of the main problems for both patients and dentists. The purpose of this study was to compare the effectiveness of premedication with indomethacin and ibuprofen for management of postoperative endodontic pain. Methods and Materials: In this clinical trial, mandibular molars with irreversible pulpitis were endodontically treated in 66 patients. The medicines were prepared similarly in the form of capsules containing 400 mg ibuprofen (group A), 25 mg indomethacin (group B) and placebo (group C). The patients were given one capsule 1 h before the start of treatment. Patients recorded their pain measured by a visual analogue scale (VAS) at medication time, during treatment and 8, 12 and 24 h after treatment. The data were analyzed using the chi-square, repeated measures ANOVA, paired t-test, Tamhane and Pearson correlation coefficient. Results: Ibuprofen and indomethacin significantly reduced the postoperative pain in comparison with placebo during treatment and 8 h after treatment; however, there were no significant differences between them 12 and 24 h after treatment. Conclusion: Premedication with ibuprofen and indomethacin can effectively control short term post-operative pain; the lower incidence of side effects and greater analgesic power of ibuprofen make it a superior choice.Keywords: Ibuprofen; Indomethacin; Irreversible Pulpitis; Non-Steroidal Anti-Inflammatory Drugs; Post-Endodontic Pai

Cytotoxicity of Cold Ceramic compared with MTA and IRM

INTRODUCTION: Biocompatibility is a desirable feature for root-end filling materials. In this study we aimed to compare a new material called cold ceramic (CC) with intermediate restorative material (IRM) and mineral trioxide aggregate (MTA) using Methyl-tetrazolium bromide (MTT) assay. MATERIALS AND METHODS: The materials were tested in fresh and set states: (n=108). The cytotoxicity was compared using L929 fibroblasts as an indicator; tested materials were eluted with culture medium according to ISO: 109935 standard. Distilled water and culture medium served as positive and negative controls, respectively (n=36). The results were evaluated at 1, 24 hours and 7 days. Data were statistically analyzed by one-way ANOVA for each time interval and material status and t-tests. RESULTS: The cytotoxicity of the tested materials were statistically different at the various time intervals (P<0.001). IRM was the most cytotoxic root-end filling material (P<0.001), MTA demonstrated the least cytotoxicity followed by CC.  CONCLUSION: Despite displaying the greatest cytotoxicity, IRM is approved by the American Food and Drug Administration (FDA). Cold ceramic had significantly lower cytotoxicity compared to IRM, in all but one subgroup. Further investigations are required to assess the clinical applicability of this novel material

Nonsurgical Endodontic Management of Large Periapical Lesion with Cold Ceramic: A Literature Review and Case Series: management of large periapical lesion

Introduction: The purpose of this review is to investigate the contribution of non-surgical endodontic treatment in the healing process of large periapical lesions as well as looking over other potential non-surgical endodontic treatment options. Materials and Methods: two females and one male patient were referred to the private office, complaining of having pain in the anterior maxillary region which was pertinent to the presence of a large periapical lesion, and subsequently were managed by a non-surgical endodontic approach using cold ceramic. The archive of PubMed and Google Scholar databases was also searched for finding relevant articles in which a nonsurgical endodontic approach was performed to improve the healing process of large periapical lesions. Results: Clinical examination of the case series subjects revealed no signs and symptoms following treatment while relative improvement of the lesion and apical closure was apparent in radiographs 7 months, 9 months, and 4 years subsequently. In twenty-two reviewed clinical trials, a total number of 107 teeth with large periapical lesions were treated by nonsurgical endodontic approaches using MTA, biodentine, gutta-percha, and bioceramic iRoot Bp plus. Complete healing occurred in 38 cases (35.5%) after 12-17 months. Conclusions: Although surgical interventions have been used previously in the management of large periapical lesions, a nonsurgical endodontic approach with cold ceramic seems to be effective, leading to complete healing of the periapical lesion in treated subjects. Further clinical research is recommended to identify the effectiveness of cold ceramic for the treatment of extensive periapical lesions

The cold ceramic material

The purpose of this paper was to review the composition, sealing ability, biocompatibility and various physical properties of cold ceramic (CC) material that potentially used as a root filling material. The review of the articles was performed by electronic and manual searching methods regarding the properties of CC from November 2000 to May 2016. The results revealed that there were many published reports carried out on the properties of CC. Only one article had extensively studied the composition of CC, five studies had investigated the sealing ability of CC, three articles had studied the biocompatibility, and some studies had investigated the radiopacity, setting time, pH value, and solubility of CC. It was concluded that CC material had good potential for endodontic use. Furthermore, clinical studies are needed in these areas

Comparison of Apical Leakage Patterns Shown by Two Different Methods

Purpose: To compare the apical leakage using dye penetration and electrochemical methods each successively used on the same teeth.Methods: 31 freshly extracted anterior single root human teeth with straight root canals were selected. The specimens were divided randomly, respectively into experimental group, two positive and two negative controls. Root canal of the case group and negative group were filled, and positive group were left unfilled. The external surface of each tooth was coated with two layers of the nail polisher, except for the apical 2mm and coronal portion. Leakage of each tooth was measured by using electrochemical test. Two copper wires were used as electrodes and normal saline solution was used as electrolyte. Then coronal portion of root were filled with the aid of ZOE cement and coated with two layers of the nail polisher. The teeth immersed in 2% basic fuchsine for 48 hours and were washed in tap water. The roots were then split longitudinally and dye leakage was assessed for each tooth.Results: No correlation was found among the results obtained with the two methods (P-Value=.297).Conclusions: Several studies are necessary before evaluation of the marginal leakage

Effect of blood contamination on marginal adaptation of cold ceramic and MTA angelus: a scanning electron microscopic study

Abstract Background This study aimed to assess the effect of blood contamination on marginal adaptation of cold ceramic (CC) and mineral trioxide aggregate (MTA) Angelus using scanning electron microscopy (SEM). Methods This in vitro experimental study was conducted on 24 extracted single-rooted human teeth. After cleaning and shaping, the root canals were filled with lateral compaction technique. The apical 3 mm of the roots was cut, and cavities with 3 mm depth were created at the apex. The teeth were randomly assigned to two group (n = 12) for the application of CC and MTA Angelus as retrograde filling materials. CC and MTA Angelus were prepared by mixing the powder with blood, and applied in the cavities. After 24 h, their marginal adaptation to the canal walls was assessed by SEM. Data were statistically analyzed by t-test (alpha = 0.05). Results The mean marginal gap was 8.98 μm in the CC, and 16.26 μm in the MTA Angelus group; this difference was statistically significant (P < 0.001). Conclusions The present in vitro study revealed that following complete blood contamination of powder, CC showed significantly superior marginal adaptation than MTA Angelus as shown by SEM assessment

Clinical and Radiographic Evaluation of Procedural Accidents and Errors during Root Canal Therapy

INTRODUCTION: Root canal therapy (RCT)_like other dental practices_ can be accompanied with some accidents or unpredictable conditions that are called "procedural accidents". Having the knowledge about these accidents and their etiology is essential to have RCT completion and to prevent the repeat of these accidents. This study was designed to evaluate accidents occurring during RCT in patients referred to endodontic department of Shahid Beheshti dental school during 2002. MATERIALS AND METHODS: This study was conducted via descriptive method. Data were collected from observation, clinical examination and oral radiographs, and were recorded in questionnaires, 150 cases from the patients referred to endodontic department were selected randomly and different observed RCT errors were analyzed by SPSS software. The Chi-square and Fisher exact tests were used for analysis. RESULTS: The study showed that 101 patients (67.3%) had one type of RCT errors, and remaining (32.7%) were error free. From the errors studied the most prevalent were "void" which was observed in 41 patients (27.3%), and "ledge" in 39 patients (26%) respectively. The prevalence of other accidents were underfilling in 35 patients (23.3%), poor shaping in 30 patients (20%), overfilling in 23 patients (15.3%), transportation in 13 patients (8.7%), zipping in 3 patients (2%), gouging in 1 patients (0.7%), and strip perforation in 1 patients (0.7%), while no case of broken instruments, vertical fracture, furcation and cervical perforation was observed. CONCLUSION: The most prevalent errors were found in instrumentation and obturation steps, therefore more care and attention must be paid to instructor observation and the education of these stages

Accuracy of Single Periapical Radiography in Diagnosis of Horizontal Root Fracture

Background and Aims: Radiographic examination is a necessary step in diagnosis of horizontal root fracture. The purpose of this study was to determine the sensitivity and specificity of single radiograph for detection of horizontal root fracture. Materials and Methods: In this analytical-descriptive study, 30 human freshly extracted teeth were used. Using a hammer and clamp, the teeth were divided into two sections accidentally and then sections were attached together by cyanoacrylate glue. Two radiographs were taken; with and without a piece of human mandibular bone. Afterward, radiographs were analyzed by three expert dentists using a slide show device. Results: The diagnostic sensitivity and specificity of single radiograph for detection of horizontal root fracture without bone was 100%, but in radiographs of teeth with bone was 82.7% and 100%, respectively. Conclusion: Based on the results of this study, in most cases, the horizontal root fractures can be detected by a single periapical radiograph