Comparative Evaluation of Dentinal Defects After Root Canal Preparation Using Various Nickel Titanium Files: An In Vitro Study.

AIM: This study set out to compare the damage done to dentin by three distinct titanium file brands - the Hyflex EDM, the ProTaper Next, and the Waveone Gold Nickel - in order to draw conclusions about which one is the most effective. MATERIALS AND METHODS: Forty-first premolars in the mandible with straight canals and single roots were instrumented using Hyflex EDM, Waveone Gold, and Protaper Next. Dentinal flaws after endodontic treatment were studied by sectioning specimens using a hard tissue microtome and analyzing them under a stereomicroscope. RESULTS: There was no discernible variation between the groups in the coronal third (p=0.312) or apical third (p=0.076). Hyflex EDM and Protaper Next differed significantly in the middle portion of the tape (p=0.016). The Hyflex EDM sample had the fewest cracks. There was no statistically significant difference between Hyflex EDM and Waveone Gold; however, Hyflex EDM had fewer fractures in the middle third of the sample than Waveone Gold did. CONCLUSION: Electric discharge machining (EDM) files made from Hyflex proved to be far superior to their Protaper Next and Waveone Gold counterparts as they induced the fewest cracks in the middle third of the root dentin.

An In-Vitro Analysis of Root Fracture Strength Using Single File Systems.

Aim Root canal obturation during endodontic therapy supports the root canal space and helps the extra tooth structure resist fracture. Some believe endodontic-treated teeth are more likely to break than natural teeth. The most common causes of tooth decay are endodontic treatment's extensive tooth structure loss and coronal and radicular dentin drying. Materials and methods Two hundred removed human permanent mandibular first molars were allowed to be stored in isotonic saline solution for a maximum of 72 hours. The collection, storing, sterilizing, and handling of the samples were done per the Occupational Safety and Health Administration (OSHA) and Centers for Disease Control and Prevention (CDC) guidelines. Out of a total of 200 newly removed mandibular first molars, 120 teeth were finally gathered, sterilized, and kept in 1% thymol in normal saline at 30 degrees Celsius. The access cavity was prepared, and the pulp chamber was cleaned and debrided using an ultrasonic scaler tip while being irrigated with regular saline. A digital radiograph was taken after a 6# K file was placed to the working length in the mesiobuccal canal. Based on their weights, the samples were dispersed equally across the six groups (n=20). They looked inside them to ensure that the root morphology was normal and that the canal was open and free of any abnormalities, damage, or fillings. They looked at the curvature of the mesial root and chose samples with a curvature of 20-35 degrees. The mesial roots were dissected, labeled, and put in a different location. Results Overall, the experimental group's incidence of buccolingual fractures was 55%, making it the most prevalent fracture type. The mesiodistal type of fracture had a 35% incidence rate, which was the second most prevalent. We found that comminuted and transverse fractures occurred in only 15% and 5% of patients, respectively, of all fractures. Both the test and the control groups had a disproportionately high number of buccolingual fractures. When comparing the root fracture loads of the two experimental groups, there was no significant difference (p>0.05) Conclusion Within this study's restrictions and standardization techniques, it can be concluded that the single file system-prepared roots' resistance to fracture was comparable to that of the control group. It is recommended to conduct additional research on these single file systems using different metrics and to assess them in a clinical setting.

Fracture resistance to treated teeth using known endodontics techniques in Indian patients.

Teeth with crown structure less than 50% can be restored. Therefore, it is of interest to evaluate an in vitro efficacy of Zirconia post, Glass fiber post, polyethylene-woven fiber posts, and Quartz posts. Forty eight recently extracted mandibular first premolar teeth were randomly grouped in to 4 different groups with 12 samples in each group. After endodontic treatment samples in all groups underwent post preparation followed by restoration with respective posts. The mean fracture resistance (Newton) were 463.5 ± 14.3 (Group I) 425.2± 23.5 (group II), 410.4± 18.6 (Group 3) and 385.2 ± 14.2 (group 4). Data shows that Zirconia post had highest fracture resistance compared to other tested groups.

Assessment of LuxaCore, Photo Core, and Core Max II on Fracture Resistance of Endodontically Treated Teeth Restored with ParaPosts and Fiber-Reinforced Composite Posts.

Objectives: The objective is to evaluate the efficacy of LuxaCore, Photo Core, and Core Max II on fracture resistance of endodontically treated teeth restored with ParaPosts and fiber-reinforced composite (FRC) posts. Materials and Methods: Ninety extracted mandibular first premolar teeth were randomly grouped into nine different groups with ten samples in each. I-FRC posts, II-FRC with Photo Core, III-FRC with LuxaCore, IV-FRC with composite core, V-FRC with Core Max II, VI-para Post (PP), VII-PP with Luxa core, VIII-PP with photo Core, IX-PP with Core Max II were compared for fracture resistance. Results: The mean fracture resistance (Newton) in group I was 452± 61.5, in group II was 412.6± 42.4 (higher from group I to group V), and lower in group VI to group IX (288 to 246.5). The mean fracture resistance of group II to V was 380.1±72.1 and group VI to IX was 62.8±70.6. The difference was statistically significant (0.001). Conclusion: FRC posts exhibited higher fracture resistance as compared to ParaPosts, and fracture resistance was not dependent on the type of material used.

Effect of Radiotherapy on Cariogenic Organism Streptococcus sobrinus in Saliva in Head and Neck Cancer: A Clinical Study.

AIM: Aim of the study was to assess salivary Streptococcus sobrinus in head and neck cancer using quantitative polymerase chain reaction (PCR). MATERIALS AND METHODS: Unstimulated saliva samples were collected from head and neck cancer patient preradiotherapy. Unstimulated saliva samples were collected from oral and laryngeal cancer patients after 6 weeks of radiotherapy (dose 60 Gy). The subjects were explained not to consume solids or liquids or carry out any dental hygiene activity 1 hour prior to saliva collection. Accumulated unstimulated saliva was collected in cylindrical tube through funnel. The collected saliva was then transferred to Eppendorf tube containing Tris-ethylenediamine-tetraacetic acid (EDTA) (TE) buffer and was transported to lab for real-time PCR analysis. RESULTS: Streptococcus sobrinus significantly increased post-radiotherapy as compared with preradiotherapy in head and neck cancer patients. CONCLUSION: Within the limitation of this study, we conclude that amount of S. sobrinus increases postradiotherapy in head and neck cancer patients. CLINICAL SIGNIFICANCE: As radiation therapy has harmful effects on hard and soft tissues of oral cavity, dentists should provide motivation for oral health care to the patients.

Evaluation of Antimicrobial Efficacy of Root Canal Sealers against Enterococcus faecalis: A Comparative Study.

AIM: The study aimed to evaluate the efficacy of root canal sealer's antimicrobial activity against Enterococcus faecalis. MATERIALS AND METHODS: Root canal sealers with the brands Endoflas FS, AH Plus, and Tubli-Seal EWT were selected. Enterococcus faecalis organisms' zone of inhibition was measured. Tukey post hoc tests and one-way analysis of variance (ANOVA) were used to compare the data among study groups and within its group. The data were said to be statistically significant with an established p-value less than 0.05. RESULTS: The maximum zone of inhibition (23.20 ± 1.202 mm) was shown by Endoflas FS sealer; AH Plus and Tubli-Seal showed the inhibition zone of (18.42 ± 1.023) and (16.88 ± 0.962) respectively, following Endoflas FS. The ANOVA test showed p < 0.0001, which is highly statistically significant. AH Plus and Endoflas FS showed a statistically significant difference of 0.04 and 0.001 in between groups, and there was no statistically significant difference in the Tubli-Seal group from Tukey post hoc test. CONCLUSION: The study showed that Endoflas FS sealer has a significant antimicrobial effect against E. faecalis. CLINICAL SIGNIFICANCE: In clinical situation, despite perfect che-momechanical root canal preparation, persistence of microorganisms may reinfect the root canal. Therefore, endodontic root canal sealers play a major role in the eradication of bacteria. The polymicrobial nature of endodontic infection plays a main role during the usage of endodontic sealer with antimicrobial agents, which in turn reduces the failure of endodontic treatment.

Comparative Evaluation of Postoperative Sensitivity in Bulk Fill Restoratives: A Randomized Controlled Trial.

AIM: Comparative evaluation of postoperative sensitivity (POS) among three bulk fill restorative materials (Cention N, Equia Forte, Activa™ Bioactive restorative) in Class I posterior restorations. MATERIALS AND METHODS: One hundred and forty-four patients having occlusal caries were arbitrarily selected and divided into three groups. Standardized Class I cavity was prepared and restored with Cention N, Equia forte, and Activa™ Bioactive restorative material. POS of restored tooth was assessed with a standardized cold test and air stimulus by air blow from the air syringe. Patient responses were assessed at an interval of 24 h, 1 week, and 1 month using a visual analog scale. Statistical analysis was performed using paired t-test, independent t-test, one-way ANOVA test, and Tukey's post hoc test using SPSS 11.0 program (SPSS Inc., Chicago, IL, USA) for windows. RESULTS: The statistical analysis showed a significant difference in the clinical evaluation of POS at 24 h interval among three groups (Cention N, Activa™ Bioactive Restorative, Equia forte). However, following 1 week and 1 month, there is no significant difference in Group C (Activa™ Bioactive Restorative). CONCLUSION: POS was seen more in Cention N contrast to Equia forte and Activa™ bioactive restorative material.

Effect of Salivary pH on Color Stability of Different Flowable Composites - A Prospective In-vitro Study.

INTRODUCTION: Scientifically and clinically there has been lot of development in the field of aesthetic dentistry. However, there is limited or restricted information regarding the color stability of flowable composite materials. AIM: The aim of this study was to evaluate the spectrophotometric color stability of three different flowable composite materials with respect to three different pH of saliva. MATERIALS AND METHODS: The study included 90 different samples. Thirty samples in each composite group; (Group A: G-aenial universal flo; Group B: Z 350 XT flowable; Group C: Esthet x flow). All samples from each group were immersed in distilled water for 24 hours. Total color difference (ΔE) was recorded for each sample. After this 10 samples from each group were respectively immersed in 6.5, 7 and 7.5 pH of artificial saliva. All samples were kept in dark room for seven days and then ΔE for each sample was recorded and was compared to previous recorded ΔE for the same sample. RESULTS: Maximum color change was seen irrespective of material in 6.5 pH of saliva. G-aenial universal flo showed least change irrespective of pH of saliva. CONCLUSION: Thus, the present study reveals that acidic pH level affects the coloration of composite resins by affecting the surface integrity and as reported in previous studies, various coloring agents in beverages and other dietary components assists the process due to absorption of these coloring substances into the resin matrix.

Comparative Evaluation of the Complementary and Alternative Medicine Therapy and Conventional Therapy Use for Musculoskeletal Disorders Management and Its Association with Job Satisfaction among Dentists of West India.

Musculoskeletal problems have become a significant issue in the profession of dentistry. There are currently no recommended effective disease-preventing and modifying remedies. High prevalence rates for musculoskeletal disorders (MSDs) among dentists have been reported in the literature. Complementary and alternative medicine can be helpful in managing and preventing the MSDs. The purpose of this study was to determine if dentists in the western part of India are using complementary and alternative medicine therapies for MSDs, and also to find if those who use complementary and alternative medicine therapies have greater job/career satisfaction compared to conventional therapy (CT) users. Dentists of western India registered under the Dental Council of India (N = 2166) were recruited for the study. Data were analyzed using univariate and bivariate analyses and logistic regression. A response rate of 73% (n = 1581) was obtained, of which 79% (n = 1249) was suffering from MSDs. The use of complementary and alternative medicine or CT was reported by 90% (n = 1124) of dentists with MSDs. Dentists using complementary and alternative medicine reported greater health (P < 0.001) and carrier satisfaction (P < 0.001) and were able to work as many hours they wanted (P < 0.001) compared to CT users. Complementary and alternative medicine therapies may improve the quality of life and enhance job satisfaction for a dentist who suffers from MSDs.

Peripheral osteoma of maxilla: A case report.

Osteoma is a benign osteogenic lesion with a very slow growth, characterized by proliferation of either compact or cancellous bone. Most cases of peripheral osteomas are asymptomatic and produce swelling and asymmetry. Its pathogenesis is unclear but commonly accepted theories propose embryologic, traumatic, or infectious causes. The osteoma may appear in the form of a limited peripheral lesion involving the alveoli or cheek or as a tumoral growth developing inward toward the sinus. Recurrences of osteomas have not been reported in the literature. We report a rare case of maxillary peripheral osteoma with impacted right canine in a 32-year-old female patient.

Characterization of the monomer-dimer equilibrium of human cytomegalovirus protease by kinetic methods.

Herpesviruses encode a serine protease that is essential for the maturation of infectious virions. This protease has a unique polypeptide backbone fold and contains a novel Ser-His-His catalytic triad. It exists in a monomer-dimer equilibrium in solution, but only the dimer form of the enzyme is catalytically active. The stability of this dimer is affected by the presence of anti-chaotropic agents. Most of the reported Kd values for this dimer (between 0.6 and 6 microM) are inconsistent with the fact that the protease is routinely assayed at 20-50 nM concentrations, as only monomeric species would be expected with such Kd values. We have characterized the monomer-dimer equilibrium of HCMV protease using a new method, which observes the exchange between dimers of the wild-type enzyme and the active-site Ser132Ala mutant in a titration experiment. The Kd of the dimer was determined to be 8 microM and 31 nM in the absence or presence of anti-chaotropic agents (10% glycerol and 0.5 M Na2SO4), respectively. Detailed kinetic analysis also showed that, in addition to the 260-fold stabilization of the dimer, the anti-chaotropic agents produced a 7-fold enhancement in the catalytic activity of the dimer.

Structural and biochemical studies of inhibitor binding to human cytomegalovirus protease.

Herpesvirus protease is required for the life cycle of the virus and is an attractive target for the design and development of new anti-herpes agents. The protease belongs to a new class of serine proteases, with a novel backbone fold and a unique Ser-His-His catalytic triad. Here we report the crystal structures of human cytomegalovirus protease in complex with two peptidomimetic inhibitors. The structures reveal a new hydrogen-bonding interaction between the main chain carbonyl of the P(5) residue and the main chain amide of amino acid 137 of the protease, which is important for the binding affinity of the inhibitor. Conformational flexibility was observed in the S(3) pocket of the enzyme, and this is supported by our characterization of several mutants in this pocket. One of the structures is at 2.5 A resolution, allowing us for the first time to locate ordered solvent molecules in the inhibitor complex. The presence of two solvent molecules in the active site may have implications for the design of new inhibitors against this enzyme. Favorable and stereospecific interactions have been established in the S(1)' pocket for one of these inhibitors.

Mutations in the relay loop region result in dominant-negative inhibition of myosin II function in Dictyostelium.

Dominant-negative inhibition is a powerful genetic tool for the characterization of gene function in vivo, based on the specific impairment of a gene product by the coexpression of a mutant version of the same gene product. We describe the detailed characterization of two myosin constructs containing either point mutations F487A or F506G in the relay region. Dictyostelium cells transformed with F487A or F506G myosin are unable to undergo processes that require myosin II function, including fruiting-body formation, normal cytokinesis and growth in suspension. Our results show that the dominant-negative inhibition of myosin function is caused by disruption of the communication between active site and lever arm, which blocks motor activity completely, and perturbation of the communication between active site and actin-binding site, leading to an approximately 100-fold increase in the mutants' affinity for actin in the presence of ATP.