Antibacterial Efficacy of Irrigants with Varying Osmolarity on E. faecalis Biofilm: An In Vitro Study.

AIM: To evaluate the role of the addition of different concentrations of sodium chloride salt to conventional intracanal irrigants to vary their osmotic values and thereby compare their antibacterial efficacy. MATERIALS AND METHODS: In an active attachment biofilm model, Enterococcus faecalis (ATCC 29212) biofilms were grown. Sodium chloride salts were added to 100 mL of distilled water to make 6M (hyperosmotic), 0.5M, and 0.25M (hypoosmotic) sodium chloride solutions, respectively. The experimental groups were divided into three groups: Group I: 5.25% sodium hypochlorite, group II: 2% chlorhexidine, and group III: 2% povidone iodine, and four subgroups within these three groups, such as subgroup A (without salt solution), subgroup B (with 6M of hyperosmotic salt solution), subgroup C (with 0.5M of hypoosmotic salt solution), and subgroup D (with 0.25M of hypoosmotic salt solution), respectively. Biofilms were treated with all the subgroups for a contact time of 15 min. A crystal violet assay was done to estimate the bacterial cell biomass. RESULTS: The results revealed that subgroups IIIB, IB, and IID, ID had a statistical reduction in bacterial biomass at p < 0.05. There were no significant differences between subgroups IC, IIC, and IIIC and subgroups IA, IIA, and IIIA. CONCLUSION: The antibacterial efficacy of all three irrigants was significantly affected by varying the osmolarities. CLINICAL SIGNIFICANCE: The results prove that the hyperosmotic and hypoosmotic salt solutions, along with irrigants, have enhanced antibacterial efficacy on E. faecalis biofilm due to its ability to vary the turgor pressure of cell wall, as well as the inherent properties of the irrigants such as hypochlorous acid formation, ionic interaction, and free radical interactions.

An interdisciplinary approach to management of diastemas: A novel classification and a case report.

Diastema between the teeth negatively affects the patients' smile, psychology and daily activities by creating a disharmony in the patients' face. The development of diastema has been attributed to several factors such as labial frenulum, microdontia, mesiodens, peg-shaped lateral incisors, agenesis, cysts, habits such as finger sucking, tongue thrusting, or lip sucking, dental malformations, genetics, proclinations, dental-skeletal discrepancies, and imperfect coalescence of interdental septum. Patients often present with complex problems that require a multidisciplinary treatment approach which includes determination of the aetiological factors, soft tissue morphology, occlusion, patient demands and aesthetic consideration to achieve satisfactory outcomes. Lack of current literature on classification of diastemas and multi-disciplinary approach of management led to the proposal of a new classification the ATAC (Anatomic and Therapeutic Classification) for management of the diastema. This case report highlights the use of the proposed classification for management of diastemas, requiring a perio-restorative intervention using a Chu's proportion gauge to achieve ideal aesthetics.

Salivary melatonin is depleted in patients with dental caries due to the elevated oxidative stress.

OBJECTIVES: To determine salivary melatonin and malondialdehyde levels in individuals with and without dental caries. MATERIALS AND METHODS: Saliva samples were collected in a fasting state from patients with active dental caries (n â€‹= â€‹16) and patients without dental caries (n â€‹= â€‹16). Melatonin was measured in the samples using a commercially available ELISA kit and malondialdehyde was assayed using a standardized spectrophotometric method. RESULTS: The salivary melatonin levels were significantly lower (p â€‹< â€‹0.01) in patients with active dental caries than patients without dental caries, while the salivary malondialdehyde values were significantly higher (p â€‹< â€‹0.01) in patients with active dental caries than patients without dental caries. The binary logistic regression analysis revealed a negative correlation (-0.513) between the salivary melatonin and malondialdehyde levels which was statistically significant (p â€‹< â€‹0.042) in the patient group with active dental caries, while no such relationship could be demonstrated in the patient group without dental caries. CONCLUSION: Melatonin depletion and augmented malondialdehyde levels potentially indicate that the endogenous melatonin has been utilized to counter the oxidative stress-induced during the initiation and progression of dental caries. Further research could explore the potential use of exogenous melatonin supplementation as a preventive and therapeutic measure for dental caries.

Fracture resistance of resin based and lithium disilicate endocrowns. Which is better? - A systematic review of in-vitro studies.

Objectives: The primary objective of this systematic review is to compare the fracture resistance of lithium disilicate (LDS)-based endocrowns and resin-based (RB) endocrowns of in-vitro studies, and the secondary objective is to compare their catastrophic failures. Materials and Methods: The review protocol was registered in the P ROSP ERO database (CRD42020166201). A comprehensive literature search was done in PubMed, Cochrane, EBSCOhost and Google Scholar using key terms. Only in-vitro studies that compared fracture resistance of LDS-based endocrowns and indirect RB endocrowns in molars were included. Data extraction, risk of bias assessment and qualitative analysis of the included studies were performed. Results: Five studies were included in this systematic review. The overall risk of bias for the included studies was moderate. Under axial loading, RB endocrowns showed similar fracture resistance when compared with LDS endocrowns. However, they showed better fracture resistance when compared with zirconia reinforced lithium silicate (ZLS) endocrowns. Furthermore, RB endocrowns showed fewer catastrophic failures than LDS-based endocrowns. Conclusions: RB endocrowns have similar or better fracture resistance and fewer catastrophic failures when compared to LDS-based endocrowns.

Evaluation of Root Dentin Thickness and Smear Layer Removal Efficacy of Two Novel Nickel Titanium Rotary Instruments - An In Vitro Cone-Beam Computed Tomography and Scanning Electron Microscopy Study.

OBJECTIVE: This study aimed to compare the two nickel-titanium (NiTi) instruments on root dentin thickness using cone-beam computed tomography (CBCT) and ability to remove the smear layer using scanning electron microscope (SEM). MATERIALS AND METHODS: The effect of two NiTi rotary instruments such as XP Endo shaper and ProTaper Gold (PTG) in retaining adequate dentin thickness and debridement (i.e., removal of smear layer) was evaluated in vitro using CBCT and SEM. After cleaning and shaping of the root canal with adequate irrigation, the effect of two NiTi instrument systems at 3 mm (apical), 6 mm (middle), and 9 mm (coronal) levels on buccal, lingual, mesial, and distal aspects in terms of amount of dentin removal and smear layer removal was evaluated. The data were analyzed using student's unpaired t-test with a significance of P ≤ 0.05. RESULTS: Both NiTi instrument systems had no statistically significant difference in amount of dentin removal at all three levels and on all four aspects. In smear layer removal, PTG had significantly better efficacy compared to XP Endo shaper at the coronal third of root canal. CONCLUSION: Instrumentation with XP Endo Shaper and PTG showed a similar amount of dentin removal. PTG has a significant effect on smear layer removal compared to XP Endo Shaper only at the coronal third of root canal.

Retention of pit and fissure sealants versus flowable composites in permanent teeth: A systematic review.

OBJECTIVE: To summarize the available clinical evidence on the relative effectiveness of retention of resin-based pit and fissure sealants (PFS) with that of flowable composites on occlusal surfaces of permanent teeth when evaluated in clinical trials. SOURCES: Electronic searches were performed in PubMed and Cochrane Library for the identification of relevant studies, from their inception until February 2020 and an additional search was done with the reference lists of included articles. STUDY SELECTION: The review protocol followed the PRISMA guidelines and was registered in PROSPERO (CRD42018112805). The risk of bias of the studies was independently appraised using the revised Cochrane Risk of Bias tool (RoB 2.0). DATA: Ten articles were considered relevant for qualitative synthesis. The data extracted from two of the included articles showed statistically significant difference between the two materials based on their retention potential, of which one article favored superior retention of flowable composites and one article favored higher retention of PFS and the other eight studies showed no significant difference between the two materials. CONCLUSION: The current review has shown evidence suggesting the effective retention of resin-based pit-and-fissure sealants and flowable composites when applied to prevent occlusal caries in permanent molars, however, this evidence is of low quality. Carefully designed long-term clinical trials are required to support the results of this review. CLINICAL SIGNIFICANCE: This is an important topic that would be of significant interest in the field of preventive dentistry, where sealants are the primary recommended method to prevent caries. The clinical efficacy of sealants is directly linked to their potential to retain and this systematic review focuses on comparing the relative effectiveness of resin-based pit-and-fissure-sealants with flowable composites in permanent teeth.

Comparative Evaluation of the Anti-bacterial Efficacy of Herbal Medicaments and Synthetic Medicaments Against Enterococcus faecalis using Real-time Polymerase Chain Reaction.

Periradicular bacterial infections are the proven cause of the failure of endodontic treatment. When the pulp canal gets infected or becomes necrotic, bacterial growth takes place in the form of biofilms and aggregates. During the endodontic procedure, bacterial colonies are disrupted, and the microbial load is reduced by biomechanical preparation, cleaning with anti-microbial solutions, and placing anti-bacterial medicaments in the root canal. These anti-microbial substances are synthetic, having a cytotoxicity effect. In recent times, herbal medicines are an alternative medicine being used increasingly as an intra-canal medicament to fight or prevent common endodontic infections. Aim The objective of this study is to compare the anti-bacterial efficacy of herbal medicaments and synthetic medicaments against Enterococcus faecalis (E. faecalis). Materials and methods This was an in-vitro study in which a total of 60 teeth specimens (n=60) were inoculated with E. faecalis for 21 days. Specimens were divided into six groups (Group 1: Piper nigrum (Piperaceae); Group 2: Piper longum (Piperaceae); Group 3: Zingiber officinale Roscoe (Zingiberaceae); Group 4: Calcium hydroxide; Group 5: 2% chlorhexidine gel (CHX); and Group 6: saline (negative control). The intra-canal medicaments were packed inside the tooth. After five days, the remaining microbial load was determined by using real-time PCR. Results The threshold cycle (Ct) values of Piper nigrum, Piper longum, dried ginger extract, 2% CHX, calcium hydroxide, and saline were found to be 21.36, 20.55, 22.14, 22.51, 23.62, and 17.81, respectively. The obtained mean bacterial load of these products was 8.64, 12.52, 7.23, 0.82, 0.14, and 149.49, respectively. Conclusion Two percent CHX showed high antibacterial activity against E. faecalis followed by calcium hydroxide, Zingiber officinale Roscoe, Piper nigrum, Piper longum, and saline.

Smear Layer Removal and Microhardness Alteration Potential of a Naturally Occurring Antioxidant - An In Vitro Study.

INTRODUCTION: It is well-known in the field of endodontics that the presence of a smear layer in the root canals can harbor bacteria and limit the penetration of irrigating solutions and intracanal medications into the dentinal tubules which, in turn, causes the failure of endodontic treatment. Removing the entire smear layer throughout the root canal is essential for the success of endodontic treatment and these chemical agents that facilitate the removal of the smear layer are called chelating agents. Ethylenediaminetetraacetic acid (EDTA), being the most widely used chelating agent, brings about increased reduction in the microhardness of the root dentin, thereby making it friable. N-acetyl cysteine (NAC) is naturally occurring antioxidant that has various beneficial properties for the human being. Several studies have been done in determining the antimicrobial efficacy of NAC against various endodontic pathogens and concluded NAC to be advantageous. The chelating property of NAC has been utilized in heavy metal detoxification, where it binds to the metal ion and removes them from the human system. However, this chelating property has not been explored in the field of endodontics. AIM: This study was aimed to compare the ability of N-acetyl cysteine with the conventional chelating agent in the removal of the smear layer and in altering the microhardness of root dentin. MATERIALS AND METHODOLOGY: A total of 84 single-rooted human mandibular premolars with relatively similar dimension and morphology, freshly extracted with closed apices, were collected from adult patients. The crowns of all specimens were cut transversally at the cementoenamel junction (CEJ) with the double-faced diamond disc at low speed, with water coolant, to obtain a 12 mm root length. The root canals were randomly divided into three equal groups according to the final irrigation solutions: Group I: 17% EDTA, Group II: 20% NAC, and Group III: distilled water (control). They were then randomly divided into two parts: scanning electron microscope (SEM) analysis for the extent of smear layer removal and microhardness evaluation using the Vicker's hardness test. RESULTS: The smear layer removal ability of EDTA and NAC were more effective in the coronal and middle thirds of the root canal. However, both groups showed less smear layer removal in the apical region. Specimens treated with distilled water showed the least reduction in the smear layer throughout the length of the root canals. Regarding the evaluation of microhardness, both EDTA and NAC had a significant reduction in root dentin microhardness. However, the percentage of dentin microhardness reduction was significantly more in the EDTA group (p < 0.05) than N-acetyl cysteine in the coronal, middle, and apical third of the root canals. CONCLUSION: The chelating property of NAC is equally effective to that of EDTA in the smear layer from the root canal, and it induced a significantly lesser reduction in microhardness of root dentin than EDTA.

Evaluation of debris and smear layer removal with XP-endo finisher: A scanning electron microscopic study.

CONTEXT: The presence of smear layer and debris can prevent the irrigant and sealer from penetrating the dentinal tubules thereby compromising the seal of the root canal filling. AIM: This study aims to evaluate the efficacy of XP-endo Finisher with ProTaper Next and HyFlex in smear layer and debris removal. MATERIALS AND METHODS: : Thirty-two extracted mandibular premolar teeth were selected and sectioned at the cementoenamel junction. The roots were then randomly divided into 4 groups. In group 1 and 2, canals were instrumented with X2 ProTaper Next (25 0.06 taper). In group 3 and 4, canals were instrumented with HyFlex system (25 0.06 taper). The canals in group 2 and 4 were further finished with XP-endo Finisher. Irrigation was carried out using 3% sodium hypochlorite during instrumentation, and 17% ethylenediaminetetraacetic acid was used as the final rinse. The roots were then split longitudinally. The canal wall was observed under the scanning electron microscope in coronal, middle, and apical thirds at a magnification of ×400 and ×1000 for evaluation of debris and smear layer, respectively. Photomicrographs were taken, and qualitative assessment for debris and smear layer removal was done. STATISTICAL ANALYSIS USED: The results were analyzed using Kruskal-Wallis test and Mann-Whitney U-test. RESULTS: Lower debris and smear layer scores were seen in canal thirds instrumented with ProTaper Next and XP-endo Finisher (P < 0.01). CONCLUSION: The use of XP-endo Finisher as an adjuvant during shaping and cleaning produced cleaner root canal walls.

Quantification of Fusobacterium nucleatum at Depths of Root Dentinal Tubules in the Tooth Using Real-time Polymerase Chain Reaction: An In Vitro Study.

INTRODUCTION: Microorganisms have been known to cause pain and infection in the tooth. Fusobacterium nucleatum was always found predominantly in failed root canal treatments. OBJECTIVE: The aim of the present study was to quantify Fusobacterium nucleatum at the inner and peripheral half of coronal, middle and apical region of the root by using real-time polymerase chain reaction (qPCR). METHODS: Extracted maxillary incisors were taken. After shaping and cleaning, the root canals were inoculated with Fusobacterium nucleatum. Samples were taken from both the inner and peripheral halves of dentin. The inoculated teeth were maintained in anaerobic jars for two weeks, and the bacterial isolates were changed every third day. The quantification was done using qPCR. RESULTS: The cycle threshold (Ct) value in all groups showed the presence of Fusobacterium nucleatum. CONCLUSION: Fusobacterium nucleatum penetrates to the entire thickness of dentin in the middle and apical region. The coaggregation with other microorganisms could be responsible for the symptomatic endodontic patients.

Comparative Evaluation of Depth of Penetration of Root Canal Irrigant After Using Manual, Passive Ultrasonic, and Diode Laser-Assisted Irrigant Activation Technique.

AIM: The aim of this study was to compare and evaluate the penetration depth of irrigant after using manual, passive ultrasonic, and diode laser-assisted irrigant activation technique. MATERIALS AND METHODS: Ninety extracted single-rooted human mandibular premolars were selected (N = 90). Teeth were decoronated and working length was standardized for 12 mm. Root canals were shaped using ProTaper Universal F3. Saline was used as an irrigant in between every successful instrumentation. After completion of chemomechanical preparation, root canals were filled with Rhodamine-B-labeled sodium hypochlorite (3%). Teeth samples were divided into three experimental groups. In Group 1 (n = 30), manual irrigant activation was performed for 30 seconds with master cone gutta-percha (F3) in gentle up and down motion. In Group 2 (n = 30), ultrasonic irrigant activation was performed using passive ultrasonic endo tips for 30 seconds. In Group 3 (n = 30), laser activation was performed using diode laser for 30 seconds with 200-µm tips. Transverse sections were made at 2, 5, and 8 mm from the root apex and were observed under confocal laser scanning microscopy. Maximum penetration depth of irrigant was recorded and statistically analyzed. RESULT: In the all three groups, coronal third (sections at 8 mm from root apex) showed the highest penetration depth of irrigant. Laser activation (Group 3) showed the highest penetration depth in all the three sections when compared with manual and passive ultrasonic irrigant activation. One-way analysis of variance and post hoc test showed there were significantly high differences among all the three groups and also at all three levels (P < 0.05). CONCLUSION: Diode laser-assisted irrigant activation technique had better penetration depth in all the three aspects of root dentin.

Immunohistochemical quantification of mast cells in inflamed and noninflamed pulp tissue.

BACKGROUND: Dental pulp inflammation is a very complex process due to its situation in low compliance (confined environment) surrounded by mineralized dentin. Mast cells are one of the mediators of inflammation. Immunohistochemical localization of mast cells by anti-tryptase antibodies in formalin-fixed paraffin-embedded sections has been shown to be highly specific. The aim of the present study is to quantify the mast cells in inflamed and noninflamed human pulp tissue using immunohistochemical analysis. MATERIALS AND METHODS: Immunohistochemical localization of mast cells by anti-tryptase antibody was done in 15 inflamed and 15 noninflamed formalin-fixed paraffin-embedded pulp tissue. A number of mast cell per five high-power fields were performed using three observers and the mean was calculated. Statistical analysis was performed using t-test. RESULTS: The results of the present study showed an increased number of mast cells in inflamed pulp in comparison with noninflamed pulp. CONCLUSION: Thus, the presence of mast cells in pulp inflammation could be used as a diagnostic marker. It can also aid in the management of pulpitis as mast cell stabilizers and antihistaminic agents could be used to control pulpal pain and inflammation.

Evaluation of bioflavonoids on the immediate and delayed microtensile bond strength of self-etch and total-etch adhesive systems to sound dentin.

AIM: This study aims to evaluate the effect of two bioflavonoids (epigallocatechin-3-gallate [EGCG] and catechin) and a protein inhibitor (chlorhexidine [CHX]) on the immediate and delayed microtensile bond strength of self-etch and total-etch adhesive systems to sound dentin. MATERIALS AND METHODS: The occlusal surfaces of 96 mandibular human third molar teeth specimens were ground after removal of the excess tissues, to expose the middle dentin. The dentin specimens were randomly allocated into four groups, each consisting of 24 teeth (n = 24) according to the application of the enzyme inhibitor. The adhesive system used in this study was Adper easy bond, a self-etch adhesive system, and Adper Single Bond 2, a total-etch adhesive system. Microtensile bond strength testing was conducted using thermocycler 2000, Heto-Holten A/S. RESULTS: All the three enzyme inhibitors increase the bond strength values of the resin-dentin interphase when used during dentin bonding. The EGCG enzyme inhibitor has shown the highest immediate bond strength to dentin when used with both the adhesive systems.

Bactericidal Effect of Different Anti-Microbial Agents on Fusobacterium Nucleatum Biofilm.

INTRODUCTION: The root canal anatomy of the teeth is very complex. Complete debridement of the root canals is a challenge and is very important for the success of the root canal treatment. Hence, this study was done to find an effective irrigant which can be used during root canal treatment. OBJECTIVE: The bactericidal effect of a potential root canal irrigant was compared with two commonly used root canal irrigants against monoculture biofilm of a commercially available isolate of Fusobacterium nucleatum. METHODS: A monoculture biofilm of Fusobacterium nucleatum was grown on glass slides. The glass slides containing the biofilm were immersed in centrifuge tubes containing 5% sodium hypochlorite, 2% Chlorhexidine, 6% turmeric solution, 9% turmeric solution and distilled water for a time span of one minute. A wire loop was used to scrape off the biofilms onto sterile brain heart infusion agar plates. This was further subjected to an incubation period of 96 hours at 37° C. Colony forming units were quantified by statistical analysis and results were obtained. RESULTS: The anti-bacterial activity of 6% and 9% turmeric solution was statistically significant against Fusobacterium nucleatum when compared to 2% Chlorhexidine and 5% sodium hypochlorite. CONCLUSION: In endodontic treatment, turmeric solution may be considered as an effective irrigant.

Comparison of the Antibacterial Efficacy of Alexidine and Chlorhexidine Against Enterococcus Faecalis: An in Vitro Study.

Introduction Root canal irrigants play an important role in reducing intracanal microorganisms, which in turn helps in achieving a successful outcome for the root canal treatment. Objective To compare the antibacterial efficacy of alexidine and chlorhexidine against Enterococcus faecalis. Methods A total of 50 extracted single-rooted teeth were randomly divided into five groups after being infected with Enterococcus faecalis. The groups were based on irrigants used: Group I - 0.4% alexidine; Group II - 1% alexidine; Group III - 1.5% percent alexidine; Group IV - 2% alexidine; Group V - 2% chlorhexidine. Following irrigation, colony-forming units were determined from the dentinal shavings collected at 400 µm depth. Results Use of 2% alexidine reduced the bacteria effectively when compared to 0.4%, 1%, and 1.5% alexidine. A statistically significant difference was not observed between 2% alexidine and 2% chlorhexidine. Discussion Alexidine, due to its higher virulence factors for bacteria and better bacterial penetrability at 400 µm depth of dentin showed better eradication of Enterococcus faecalis in comparison to chlorhexidine. Conclusion The use of 2% alexidine against Enterococcus faecalis at 400 µm depth of dentin has efficacy comparable to chlorhexidine. Hence, alexidine can be used as an alternative irrigant for chlorhexidine during endodontic procedures.

The Effect of Addition of an EPS Degrading Enzyme with and without Detergent to 2% Chlorhexidine on Disruption of Enterococcus faecalis Biofilm: A Confocal Laser Scanning Microscopic Study.

BACKGROUND: Enterococcus faecalis is one of the most commonly occurring organisms retrieved from root canal treated teeth that show refractory apical periodontitis. Though it is well known that the ability of E. faecalis to form a matrix-encased biofilm contributes to its pathogenicity, the role of extracellular dextran and DNA in biofilm formation and its effect on the susceptibility of the biofilm to chlorhexidine remains poorly understood. It was hypothesized that the addition of an Extracellular Polymeric Substance (EPS) degrading enzyme along with a detergent to chlorhexidine may increase the susceptibility of the E. faecalis biofilm. AIM: To evaluate the sensitivity of Enterococcus faecalis biofilms treated with DNase enzyme and their susceptibility to 2% chlorhexidine used alone or in conjunction with a detergent in a dentin disinfection model and examine under confocal laser scanning microscopy (CLSM). MATERIALS AND METHODS: Semi cylindrical shaped dentin specimens were infected with E. faecalis and incubated for 24 hours. Following incubation, the infected dentin specimens were exposed for 3 minutes to the four disinfecting solutions and grouped accordingly. {Group I- Sterile saline, Group II- 2% Chlorhexidine (CHX), Group III- Dnase1 Enzyme + 2% CHX, Group IV- DNase1 Enzyme + 2% CHX & Tween 80. Bacterial viability was then assessed by staining the specimens and examining under CLSM to analyse the proportion of dead and live bacteria within the dentinal tubules. RESULTS: The Groups II, III and IV showed statistically significant (p<0.05) percentage of dead bacteria compared to the control (Group I). However there was no significant difference in the killing effectiveness within the experimental groups (II-IV) at (p<0.05). CONCLUSION: EPS degrading enzyme (DNase I) disrupts the biofilm and increases the susceptibility of E.faecalis when exposed to 2% Chlorhexidine and the use of a surfactant with this combination significantly contributes to improving the antibacterial efficacy.

Evaluation of dental expertise with intra-oral peri-apical view radiographs for forensic identification.

BACKGROUND: Identification of a dead person is important in starting the investigation into the circumstances of death. In the absence of forensic odontologist, it is vital that general dentists are able to compare the ante mortem-post mortem (AM-PM) records and with their ability, correctly interpret the individuality of the person. AIMS: This study wascarried out to find out the accuracy with which undergraduate, graduate and post-graduate dentists can do this comparison, using the simulated AM-PM intra-oral peri-apical (IOPA) view radiographs. SETTING AND DESIGN: A total of 60 investigators of which 20 undergraduate students, 20 general dentists, 20 post-graduate dentists viewed 10 pairs of simulated AM and PM radiographs and recorded their findings. MATERIALS AND METHODS: Ten pairs of simulated AM-PM IOPA view radiographs were given to 60 dentists to investigate their discriminatory potential for dental identification purposes. The results were statistically analyzed. STATISTICAL ANALYSIS: χ(2) -test and Mann-Whitney U-test were carried out to compare the sensitivity, specificity and accuracy of the three types of examiners (UG, G, PG). RESULTS: The results showed sensitivity of 59.8%, specificity of 62.6%, accuracy of 61% for undergraduate students, sensitivity of 86.6%, specificity of 87.5%, accuracy of 87% for graduate doctors, sensitivity of 89.3%, specificity of 92.3% and accuracy of 90.5% for post-graduate doctors respectively. CONCLUSION: Inexperienced investigators in forensic identification showed fairly acceptable results, therefore, introduction of forensic odontology in an undergraduate course may help general dentists to provide better service, if required, in the absence of a forensic odontologist.

A comparative assessment of fracture resistance of endodontically treated and re-treated teeth: An in vitro study.

AIM: To compare and assess the fracture resistance of endodontically treated teeth with those that have been subjected to endodontic retreatment. MATERIALS AND METHODS: 30 extracted mandibular premolars were decoronated at cementoenamel junction and randomly divided into 2 groups. In Group I endodontic treatment was performed with ProTaper rotary system till size F2 and obturated. In Group II, cleaning and shaping was done and teeth were subjected to Spiral CT to assess the remaining dentin thickness and obturated. Later retreatment was done using Protaper Universal Retreatment system and final shaping was performed till size F3. Remaining dentin thickness was again assessed using Spiral CT and then obturated. All the specimens were subjected to fracture resistance using universal testing machine. The results were statistically analyzed using Independent Samples t-test for analysis of remaining dentin thickness using SCT within Group II and Paired Samples t-test was used for assessment of fracture resistance between Group I and II (P < 0.05). RESULTS: In Group II, the intra group comparison of the remaining dentin thickness in the coronal third reveals statistical significance, with a significant difference noted in the apical third. Results of the fracture resistance reveal a statistically significant difference (P < 0.05) between Groups I and II with the mean fracture resistance of Group I being higher than Group II. CONCLUSION: Endodontically retreated teeth have shown significantly decreased resistance to fracture and this has a positive correlation to the increased loss of root dentin during the retreatment procedures.

Profilometric analysis of two composite resins' surface repolished after tooth brush abrasion with three polishing systems.

AIM: To evaluate the effect of three polishing protocols that could be implemented at recall on the surface roughness of two direct esthetic restorative materials. MATERIALS AND METHODS: Specimens (n = 40) measuring 8 mm (length) × 5 mm (width) × 4 mm (height) were fabricated in an acrylic mold using two light-cured resin-based materials (microfilled composite and microhybrid composite). After photopolymerization, all specimens were finished and polished with one of three polishing protocols (Enhance, One Gloss, and Sof-Lex polishing systems). The average surface roughness of each treated specimen was determined using 3D optical profilometer. Next all specimens were brushed 60,000 times with nylon bristles at 7200 rpm using crosshead brushing device with equal parts of toothpaste and water used as abrasive medium. The surface roughness of each specimen was measured after brushing followed by repolishing with one of three polishing protocols, and then, the final surface roughness values were determined. RESULTS: The data were analyzed using one-way and two-factor analysis of variance (ANOVA) and Tukey's honestly significant difference (HSD). Significant difference (P < 0.05) in surface roughness was observed. Simulated brushing following initial polishing procedure significantly roughened the surface of restorative material (P < 0.05). CONCLUSION: Polishing protocols can be used to restore a smooth surface on esthetic restorative materials following simulated tooth brushing.

Influence of different organic solvents on degree of swelling of poly (dimethyl siloxane)-based sealer.

The study evaluated the compatibility of chloroform, ether, and xylene with poly(dimethyl siloxane) (PDMS) based sealer. Freshly mixed sealer was placed in 90 glass molds with 5 mm diameter and 2 mm thickness. All samples were stored in 75% relative humidity at 37°C for 2 weeks. All the samples were divided into three groups: group A - chloroform; group B - ether, and group C - xylene and immersed in fresh solvent at room temperature. The specimens were weighed before and after immersion for each group at the end of 2, 5, and 10 min. The swelling ratio was calculated for all the groups. Intergroup comparison revealed no difference in the mean swelling ratio for 2, 5, and 10 min (P > 0.001; Tukey HSD Post Hoc). Intragroup comparison revealed significant difference in swelling ratio between 2 and 5 min for group B and group C (P < 0.001; Paired t test). Ether has the highest compatibility with PDMS-based sealer after 2 min followed by xylene after 5 min.