In vitro evaluation of the effect of addition of biomaterials to carbamide peroxide on the bleaching efficacy and microhardness of enamel.

Background and Aim: Teeth bleaching, although considered safe and conservative, cause microscopic changes in the tooth structure. The aim of this study is to evaluate the bleaching efficacy of carbamide peroxide (CP) bleaching gel when modified with the incorporation of bioactive glass (BG) and hydroxyapatite (HA) and its effect on enamel microhardness. Materials and Methods: Forty-five maxillary incisors were decoronated, artificially stained and mounted in acrylic. The samples were divided into three groups of 15 each and subjected to the following bleaching protocol for 8 h/day at 37°C for 2 weeks: Group 1 - 16% CP, Group 2 - CP modified with BG, and Group 3 - CP modified with hydroxyapatite (HA). Spectrophotometric color assessment using CIE L*a*b* system and Vickers microhardness were assessed before and after bleaching. Data were analyzed using Student's paired t-test and one-way ANOVA followed by Tukey's post hoc analysis. Results: There was a significant change in color (L*a*b*) in all the three groups when compared to the baseline values. However, no significant difference in the total color change (ΔE) was observed between the three groups. Enamel microhardness reduced significantly in the CP group, whereas it increased in the BG and HA group after bleaching. Scanning electron microscopy images of BG and HA groups showed crystalline deposits suggesting mineral deposition. Conclusion: Addition of biomaterials can be a beneficial alternative to bleaching with CP alone, considering the increase in microhardness without hindering the bleaching action.

A Community Trial in Coastal Karnataka using Life Style Modifications to Assess its Impact on Hypertension and Diabetes.

Introduction: In the management of hypertension and diabetes mellitus, a systematic response like modifications in lifestyles is needed along with the medication. The study was conducted to determine the impact of comprehensive lifestyle modifications on hypertension and diabetes and to compare it with that of physical activity alone as a health education intervention. Materials and Method: A risk factor-based community intervention trial was conducted for one year in 3 villages in coastal Karnataka. The sample of 305 was calculated depending on the expected change in blood pressure and an equal sample size was drawn from each of the villages using a systematic random sampling method. Baseline data on blood pressure level, random blood sugar, and HbA1c levels were recorded. After 1 year of intervention, all the parameters were further recorded along with the adherence to medication for these non-communicable diseases. Results: The mean difference between the groups suggested that participants with physical activity intervention reported a statistically significant reduction in systolic blood pressure. In the comprehensive lifestyle modification group, there was a significant reduction in both diastolic blood pressure and glycated hemoglobin levels (21 mmHg and 2.1%; p < 0.001). Conclusion: The study indicates that in the management of hypertension and diabetes mellitus, the impact of comprehensive lifestyle modifications was more significant compared to physical activity alone.

Genomic Surveillance for SARS-CoV-2 Variants: Circulation of Omicron Lineages - United States, January 2022-May 2023.

CDC has used national genomic surveillance since December 2020 to monitor SARS-CoV-2 variants that have emerged throughout the COVID-19 pandemic, including the Omicron variant. This report summarizes U.S. trends in variant proportions from national genomic surveillance during January 2022-May 2023. During this period, the Omicron variant remained predominant, with various descendant lineages reaching national predominance (>50% prevalence). During the first half of 2022, BA.1.1 reached predominance by the week ending January 8, 2022, followed by BA.2 (March 26), BA.2.12.1 (May 14), and BA.5 (July 2); the predominance of each variant coincided with surges in COVID-19 cases. The latter half of 2022 was characterized by the circulation of sublineages of BA.2, BA.4, and BA.5 (e.g., BQ.1 and BQ.1.1), some of which independently acquired similar spike protein substitutions associated with immune evasion. By the end of January 2023, XBB.1.5 became predominant. As of May 13, 2023, the most common circulating lineages were XBB.1.5 (61.5%), XBB.1.9.1 (10.0%), and XBB.1.16 (9.4%); XBB.1.16 and XBB.1.16.1 (2.4%), containing the K478R substitution, and XBB.2.3 (3.2%), containing the P521S substitution, had the fastest doubling times at that point. Analytic methods for estimating variant proportions have been updated as the availability of sequencing specimens has declined. The continued evolution of Omicron lineages highlights the importance of genomic surveillance to monitor emerging variants and help guide vaccine development and use of therapeutics.

Antibacterial efficacy of nisin, calcium hydroxide, and triple antibiotic paste in combination with chitosan as an intracanal medicament against Enterococcus faecalis - An in vitro study.

Aims: Evaluate and compare antibacterial efficacy of nisin, calcium hydroxide (Ca (OH)2), and Triple antibiotic paste (TAP) mixed with distilled water and chitosan as an intracanal medicament on Enterococcus faecalis after 1st and 7th day. Settings and Design: Experimental in vitro study. Materials and Methods: One hundred and twenty Decoronated single-rooted premolars were prepared and autoclaved. Specimens were placed in brain heart infusion (BHI) broth of a 24 h old E. faecalis (ATCC 29212) suspension. The canal was infected for 21 days, followed by grouping as-Group 1: Nisin + distilled water; Group 2: Nisin + 2% chitosan; Group 3: Ca (OH)2 + distilled water; Group 4: Ca (OH)2 + 2% chitosan; Group 5: TAP + distilled water; Group 6: TAP + 2% chitosan and were incubated for 1 and 7 days. Dentin scrapings from 10 specimens at each time interval were transferred into BHI broth and incubated, Serially diluted and colony-forming unit (CFU) count was assessed after 1st and 7th day. Statistical Analysis Used: Kruskal-Wallis test to compare mean CFUs after day 1 and day 7. Mann-Whitney post hoc Analysis to estimate significance. Wilcoxon Signed-Rank Test to compare mean CFUs between day 1 and day 7. Results: After 1 day, Group 6 showed least CFUs than other groups and highest CFUs was with Group 3. There was no difference statistically when Group 5 and Group 2 were compared. After 7 days, Group 6 showed least CFUs than other groups with no significant difference between Group 1 and Group 5 as well as no significant difference between Group 2, Group 5 and Group 6. Conclusions: TAP with chitosan can be the medicament of choice for 1-day placement and was equivalent to nisin with chitosan combination after 7 days.

Corono-radicular reinforcement with minimal invasion: A novel case report.

Maxillary premolar with an oval-shaped canal always poses a challenge while reconstruction using the post and core system. Fiber-post has many advantages over metallic-post and so fiber-post is becoming more popular and particularly widely used than metallic-post nowadays. Fiber-post has benefits of esthetic and strength, and its combination with flexible material, Ribbond has provided it with a high rise in the field of dentistry. The purpose of this case report was to show an innovative technique to place both glass fiber-post and Ribbond as a single assembly into the canal which gives a monoblock effect. This technique is feasible and may eradicate some of the problems associated with the cementation of ill-fitted fiber-post in an oval-shaped canal with widened canal space.

Genomic Surveillance for SARS-CoV-2 Variants: Predominance of the Delta (B.1.617.2) and Omicron (B.1.1.529) Variants - United States, June 2021-January 2022.

Genomic surveillance is a critical tool for tracking emerging variants of SARS-CoV-2 (the virus that causes COVID-19), which can exhibit characteristics that potentially affect public health and clinical interventions, including increased transmissibility, illness severity, and capacity for immune escape. During June 2021-January 2022, CDC expanded genomic surveillance data sources to incorporate sequence data from public repositories to produce weighted estimates of variant proportions at the jurisdiction level and refined analytic methods to enhance the timeliness and accuracy of national and regional variant proportion estimates. These changes also allowed for more comprehensive variant proportion estimation at the jurisdictional level (i.e., U.S. state, district, territory, and freely associated state). The data in this report are a summary of findings of recent proportions of circulating variants that are updated weekly on CDC's COVID Data Tracker website to enable timely public health action.† The SARS-CoV-2 Delta (B.1.617.2 and AY sublineages) variant rose from 1% to >50% of viral lineages circulating nationally during 8 weeks, from May 1-June 26, 2021. Delta-associated infections remained predominant until being rapidly overtaken by infections associated with the Omicron (B.1.1.529 and BA sublineages) variant in December 2021, when Omicron increased from 1% to >50% of circulating viral lineages during a 2-week period. As of the week ending January 22, 2022, Omicron was estimated to account for 99.2% (95% CI = 99.0%-99.5%) of SARS-CoV-2 infections nationwide, and Delta for 0.7% (95% CI = 0.5%-1.0%). The dynamic landscape of SARS-CoV-2 variants in 2021, including Delta- and Omicron-driven resurgences of SARS-CoV-2 transmission across the United States, underscores the importance of robust genomic surveillance efforts to inform public health planning and practice.

Visible light photodegradation of 2,4-dichlorophenol using nanostructured NaBiS2: Kinetics, cytotoxicity, antimicrobial and electrochemical studies of the photocatalyst.

Removal of the hazardous and endocrine-disrupting 2,4-dichlorophenol (2,4-DCP) from water bodies is crucial to maintain the sanctity of the ecosystem. As a low bandgap material (1.37 eV), NaBiS2 was hydrothermally prepared and used as a potential photocatalyst to degrade 2,4-DCP under visible light irradiation. NaBiS2 appeared to be highly stable and remained structurally undeterred despite thermal variations. With a surface area of 6.69 m2/g, NaBiS2 has enough surface-active sites to adsorb the reactive molecules and exhibit a significant photocatalytic activity. In alkaline pH, the adsorption of 2,4-DCP on NaBiS2 appeared to decrease whereas, the acidic and neutral environments favoured the degradation. An increase in the photocatalyst dosage enhanced the degradation efficiency from 81 to 86 %, because of higher vacant adsorbent sites and the electrostatic attraction between NaBiS2 and 2,4-DCP. The dominant scavengers degraded 2,4-DCP by forming a coordination bond between chlorine's lone pair of electrons and the vacant orbitals of bismuth, following the order hole> OH > singlet oxygen. Being non-toxic to both natural and aquatic systems, NaBiS2 exhibits antifungal properties at higher concentrations. Finally, the electron-rich NaBiS2 is an excellent electrocatalyst that effectively degrades organic pollutants and is a promising material for industrial and environmental applications.

Evaluation of Immediate and Delayed Microleakage of Class V Cavities Restored with Chitosan-incorporated Composite Resins: An In Vitro Study.

AIM AND OBJECTIVE: To evaluate and compare the microleakage of unmodified microhybrid composite and 0.2% chitosan-incorporated composite in class V cavities restored immediately and after 3 months of storage in artificial saliva. MATERIALS AND METHODS: Sixty human permanent maxillary premolars were collected and standardized class V cavity prepared on the buccal surface of each tooth with dimensions: mesiodistally 3 mm, occluso cervically 2 mm, and depth of 1.5 mm and restored with microhybrid composite and chitosan-incorporated composite resins respectively and randomly divided: Group I: control-microhybrid composite (n = 30): (a) 15 teeth tested immediately (b) 15 teeth tested after 3 months. Group II-restored with chitosan + composite (n = 30): (a) 15 teeth tested immediately (b) 15 teeth tested after 3 months. Specimens were stored in artificial saliva following which a dye extraction test was carried out using a spectrophotometer. RESULTS: There was no statistically significant difference in microleakage score between the chitosan-composite group and unmodified composite group when evaluated immediately after placing the restoration. Microleakage values of the unmodified composite group increased significantly after 3 months of storage in artificial saliva and values of the chitosan-composite group did not differ significantly even after 3 months of storage. Microleakage was seen significantly less in the chitosan-composite group compared to the unmodified composite group after 3 months of storage in artificial saliva. CONCLUSION: It can be concluded that chitosan-incorporated composite seems to have improved mechanical properties and forms a more stable bond when compared with unmodified microhybrid composite in addition to being antibacterial. CLINICAL SIGNIFICANCE: Considering the advantageous properties of this material, it may be clinically useful in restoring class V cavities in patients with high caries risk. However, further in vitro and in vivo studies need to be carried out. HOW TO CITE THIS ARTICLE: Deb A, Pai V, Nadig RR. Evaluation of Immediate and Delayed Microleakage of Class V Cavities Restored with Chitosan-incorporated Composite Resins: An In Vitro Study. Int J Clin Pediatr Dent 2021;14(5):621-627.

SPS(Kayexalate)/CPS(K-Bind) crystals in the gastrointestinal tract-An experience from a tertiary center.

INTRODUCTION: Kayexalate (Sodium Polystyrene Sulfonate/SPS) and K-bind (Calcium Polystyrene Sulfonate/CPS) are cation exchange resins, commonly used for treatment of hyperkalaemia. SPS/CPS induced injury of the gastrointestinal tract(GIT) is rare, can be potentially life threatening but is under-recognized. This study aims to increase awareness of pathologists and clinicians of this under-reported complication of a drug commonly used to treat hyperkalaemia. MATERIALS: Study population comprised patients with SPS/CPS (Kayexalate or its analogues) crystals identified in gastrointestinal specimens from 2017-2019 at a tertiary care centre. Clinical details, relevant investigations, imaging and endoscopic findings, patient follow up details were obtained from the hospital electronic information system. RESULTS: A total of 10 patients with SPS/ CPS crystals in the GIT were encountered over 2 years. Male to female ratio was 9:1, with mean age 66.5years (range 52-82 years). Eight cases were mucosal biopsies and 2 were resection specimens. Additional pathology (tumours, colonic perforation) was present in 80% of patients. The characteristic morphological appearance of the CPS/SPS crystals on H&E stains were supported by special stains -Periodic acid Schiff(PAS) and Acid fast Bacilli(AFB). In all cases, the treatment history with SPS/CPS for hyperkalaemia was obtained only after the histological examination. Most common etiology of hyperkalaemia encountered was chronic kidney disease(CKD)/ Acute on chronic kidney disease. CONCLUSION: It is important for pathologists to recognise the presence of these crystals especially in small biopsies as early feedback to clinicians can help in appropriate management and avoidance of more serious adverse outcome. To the best of our knowledge, this is the first series of 10 consecutive cases of SPS/CPS crystals encountered in gastrointestinal tract to be reported from India.

Evaluation of Microleakage of Micro Hybrid Composite Resins versus Chitosan-Incorporated Composite Resins When Restored in Class V Cavities Using Total Etch and Self-Etch Adhesives: An In vitro Study.

AIM: To evaluate the in-vitro microleakage of traditional micro hybrid composite resin and 0.2% chitosan-incorporated composite resin when restored in Class V cavities using total etch versus self-etch adhesives after storing in artificial saliva for 24 h. MATERIALS AND METHODOLOGY: Sixty permanent maxillary premolars collected and Class V cavities were prepared on buccal surface of each tooth (dimensions: mesio-distally 3 mm, occluso cervically 2 mm, and depth of 1.5 mm) and restored with Group 1: micro hybrid (30 teeth) and Group 2: chitosan-incorporated composite (30 teeth), which was further subdivided into: (a) 15 teeth using total-etch adhesives. (b) 15 teeth using self-etch adhesives. Next dye extraction test was carried out using spectrophotometer. RESULTS: Comparison within groups: In Group 1: Self-etch demonstrated less microleakage (0.0129) compared with total etch (0.0183). The difference was statistically significant, and in Group 2: No statistically significant difference was found in mean microleakage scores after using either self-etch (0.0118) or total etch adhesives (0.0120). CONCLUSION: It can be concluded that chitosan-incorporated composite seems to have improved mechanical properties with a stable bond when used with either self-etch or total etch adhesives in addition to being antibacterial. It may be clinically useful in restoring Class V cavities in patients with high caries risk. However, further in vitro and in-vivo studies need to be carried out.

Microtensile Bond Strength of Composite Resin Following the Use of Bromelain and Papain as Deproteinizing Agents on Etched Dentin: An In Vitro Study.

AIM AND OBJECTIVES: The aim of this study was to evaluate and compare the deproteinizing effect of sodium hypochlorite, bromelain, and papain on microtensile bond strength of composite resin to etched dentin. MATERIALS AND METHODS: Eighty freshly extracted permanent molars were wet grounded into a flat surface using a diamond disk to expose the superficial dentinal surface. Teeth were etched with 37% phosphoric acid for 15 seconds and rinsed with water and blot dried. Teeth were divided into four groups (n = 20) based on the method of dentin deproteinization. Group I: only etching; group II: deproteinized with 5.25% sodium hypochlorite for 1 minute; group III: deproteinized with 8% bromelain enzyme for 1 minute; and group IV: deproteinized with 8% papain enzyme for 1 minute. All the samples were washed off with distilled water to remove deproteinizing agents. Sample surfaces were blot dried and bonding of the dentin surface was performed and restored with light cure bulk fill composite. Samples were stored in distilled water (37°C/24 hours) and thermocycled. Then, the teeth were longitudinally sectioned and individually fixed to a sectioning block using acrylic resin. The block was mounted on hard tissue microtome and sectioned to get one to three slabs of 1 mm thick sections. The beam was then attached to a custom-made jig using screws subjected to the Instron universal testing machine. A tensile load was applied at a crosshead speed of 0.5 mm/minute until the beam fractured. RESULTS: Higher mean bond strength was recorded in group IV followed by group III, group II, and group I, respectively. Group III presented a statistically significant highest mean score compared to other study groups with group I and group II (p < 0.001), followed by group IV having significantly higher mean score compared to group I and group II (p < 0.001) and finally a significant difference was observed between group II and group I (p < 0.001). However, the mean microtensile bond strength score did not differ significantly between group III and group IV (p = 0.20). CONCLUSION: Within the limitations of this present in vitro study, the following conclusions were drawn. The microtensile bond strength of dentine tested in various deproteinizing agents is as follows: 8% bromelain > 8% papain > 5.25% NaOCl > control group. Naturally occurring deproteinizing agents, such as bromelain and papain, used in this study have resulted in greater bond strength values when compared to that of traditionally used chemical agent such as NaOCl. HOW TO CITE THIS ARTICLE: Khatib MS, Devarasanahalli SV, Aswathanarayana RM, et al. Microtensile Bond Strength of Composite Resin Following the Use of Bromelain and Papain as Deproteinizing Agents on Etched Dentin: An In Vitro Study. Int J Clin Pediatr Dent 2020;13(1):43-47.

Intrafetal laser for midtrimester TRAP sequence-experience from a single center.

OBJECTIVE: To report our experience and evaluate outcomes in monochorionic pregnancies with Twin Reversed Arterial Perfusion sequence with intrafetal laser therapy. METHODS: Retrospective review of records of all pregnancies with TRAP sequence treated by intrafetal laser therapy between 2011 January and 2015 December that were retrieved and analysed. RESULTS: Electronic search of the scan database retrieved 57 cases of TRAP sequence during the study period, 7 triplets and 50 monochorionic twins. Intrafetal laser was done in 27 cases, 22 cases of twins and 5 cases of triplets. In the twins group, median gestational age at intervention was 22.5 weeks, the earliest done at 16.3 weeks. The median gestational age at delivery and birth weight was 37 weeks and 2.5 Kgs. The median procedure and delivery interval was 14 weeks. Live birth rate was 17/22 (77%) the pump survival rate was 16/22 (73%). Pregnancies with non-surviving pump were 5 in numbers (5/22). A repeat procedure was warranted in one case. In the triplet group, median gestational age at intervention, delivery and procedure delivery interval was 18, 35 and 17 weeks. CONCLUSION: Intrafetal laser is simple, effective and the treatment of choice to interrupt the vascular supply to acardiac twin.

To evaluate the fracture resistance of proclined endodontically treated teeth with different post and core systems: In vitro study.

AIM: This study was aimed to evaluate the fracture resistance of proclined endodontically treated teeth with different post and core systems. SETTINGS AND DESIGN: Experimental in vitro study. METHODOLOGY: Eighty extracted maxillary central incisors were selected and decoronated keeping 2 mm of crown ferrule and were endodontically treated. Postspace was prepared retaining 5 mm apical gp using peeso 3. Samples were divided into two groups. In Group 1, Wax pattern fabricated to accommodate different core angulations to be casted with Ni-Cr alloy. In Group 2, ever stick posts were angulated and cemented followed by porcelain fused to metal crown cementation for both the groups. Samples were thermocycled and subjected to the universal testing machine. STATISTICAL ANALYSIS USED: One-way ANOVA and Tukey's post hoc test were used to compare the mean fracture resistance between different angulations in cast post and ever stick posts. Student's paired t-test was used to compare the mean fracture resistance between cast post and everstick posts for each angulations. P value was set at P < 0.05. RESULTS: The fracture resistance was the highest at 20° and lowest at 30° core angulations in both the groups. CONCLUSIONS: Changing core angulation up to 20° can be carried out safely using any of the post systems tested in the study. Core angulations >20°, should be used with caution, especially in patients with abnormal parafunctional habits and occlusal trauma.

Prognostic and predictive significance of microsatellite instability in stage II colorectal carcinoma: An 8-year study from a tertiary center in South India.

BACKGROUND: Microsatellite instability (MSI) accounts for 15-20% of colorectal cancer (CRC) and is considered to have favorable stage-adjusted prognosis compared to Microsatellite stable (MSS) CRCs. Determination of MSI in stage II CRC is important for management decisions regarding adjuvant chemotherapy administration. The aim of this study was to determine the prognostic and predictive significance of MSI in stage 2 CRC in the Indian scenario. MATERIALS AND METHODS: A total of 195 patients who underwent curative surgery for stage II CRC from 2010 to 2017 were included. MSI testing by immunohistochemistry (DNA MisMatch Repair proteins) was performed in all. Various clinicopathological factors and disease-free survival and overall survival were assessed between MSI and MSS groups. The effect of treatment in terms of survival benefits with adjuvant therapy in the MSI group was also assessed. RESULTS: 27.1% of the CRCs' showed MSI. Younger age (<50 years), family history of cancer, synchronous/metachronous malignancies, proximal (right sided) location, poor morphological tumour differentiation, mucin production, and presence of peritumoral (Crohn's-like) lymphocytic response showed statistically significant association with MSI. Majority (56%) of our patients showed combined loss of MLH1 and PMS2. Overall, survival among the MSI patients was significantly higher (76.6 ± 4.149 months) than the MSS patients (65.05 ± 3.555)P= 0.04. MSI patients did not show any differences in survival with or without treatment. CONCLUSION: This study highlights the distinct clinicopathological features of MSI-related CRC and the relevance of MSI testing of stage II CRC for management decisions and prognostication.

Radicular Peroxide Penetration from Different Concentrations of Carbamide Peroxide Gel during Intracoronal Bleaching-An In vitro Study.

AIM: The aim of this study is to evaluate and compare the amount of radicular peroxide penetration when various concentrations of carbamide peroxide (CP) bleaching gels (10, 15, and 35%) and a mixture of 30% hydrogen peroxide (HP) with sodium perborate are used for intracoronal bleaching. MATERIALS AND METHODS: Fifty extracted single-rooted premolars from young adults were used. The specimens were then divided into five groups such that teeth with varying sizes were equally distributed in all groups. Group I-distilled water (control group), group II-10% CP, group III-15% CP, group IV-35% CP, and group V-30% HP with sodium perborate. Intermediate restorative material (IRM) was used to seal access cavities and left for a week at 37 °C in an incubator. Following the bleaching process, suspended teeth from plastic tubes containing distilled water were removed and the water was used to determine the amount of peroxide levels. A UV-visible spectrophotometer at a wavelength of 480 nm was used to determine the quantity of peroxide based on the optical density. RESULTS: Results showed the highest peroxide leakage in group V, followed by group IV, and then group III, whereas the least peroxide penetration was found in group II, and the control group or group I showed no penetration. The Kruskal-Wallis test showed a significant difference between the various groups tested. The Mann-Whitney test was done to find in which pair of groups there exists a significant difference. It was found that all the groups when compared among themselves showed a significant difference. CONCLUSION: The present study concluded that lower concentrations of CP 10 and 15% produced lower peroxide leakage. Hence, it could be tried as an alternate to traditional agents in cases with compromised tooth which shows cervical tooth defects where the risk of external root resorption is higher. CLINICAL SIGNIFICANCE: The management of discolored teeth involves different techniques; among various techniques, bleaching is considered to be a safe, effective, and relatively noninvasive technique to lighten discolored teeth and it also conserves dental hard tissue.

Comparison and evaluation of surface deformation of Hyflex controlled memory and Hyflex electric discharge machining nickel titanium rotary files and cyclic fatigue resistance after instrumentation and heat sterilization - An in vitro study.

AIMS: The aim of this study is to evaluate and compare the surface deformation and cyclic fatigue resistance of Hyflex controlled memory (CM) and Hyflex electric discharge machining (EDM) files following instrumentation and heat sterilization. SUBJECTS AND METHODS: Thirty Hyflex CM and thirty Hyflex EDM files were selected and profilometric images taken. Sixty extracted molars were decoronated, cleaning and shaping done with files, and subjected to autoclaving. Profilometric images were taken after instrumentation and sterilization. Cyclic fatigue testing was done at 30° and 60° in a custom-made jig. STATISTICAL ANALYSIS USED: The Mann-Whitney test was used to compare profilometer and cyclic fatigue values between Hyflex CM and Hyflex EDM groups, whereas Friedman's and Wilcoxon signed-rank test were used for intragroup comparisons. RESULTS: Intact Hyflex EDM files showed higher surface roughness values compared to Hyflex CM. Hyflex CM showed an increase in surface roughness after instrumentation and sterilization that was statistically significant while Hyflex EDM showed no statistical significance both after instrumentation and sterilization. Hyflex EDM showed a significantly higher mean number of cycles to failure than Hyflex CM at both degrees. CONCLUSIONS: Hyflex EDM files are able to maintain their surface topography and also have cyclic fatigue resistance better than Hyflex CM after both instrumentation and sterilization.

Comparative evaluation of smear layer removal by chitosan and ethylenediaminetetraacetic acid when used as irrigant and its effect on root dentine: An in vitro atomic force microscopic and energy-dispersive X-ray analysis.

AIM: This study was undertaken to evaluate the efficacy of smear layer removal and nanostructural and chemical changes caused by chitosan and ethylenediaminetetraacetic acid (EDTA) on tooth surface using atomic force microscopic analysis and energy-dispersive X-ray (EDX) analysis. METHODOLOGY: Forty single-rooted premolars were decoronated to a standard length of 15 mm and enlarged to Protaper F3 with irrigation of 1 mL 1% NaOCl and deionized water. Specimens were then divided into 4 groups with 10 samples each and subjected to final rinse with 17% EDTA solution, 0.2% and 0.5% chitosan solution for 1 min. Samples were sectioned into 2 halves. One half of sample from each group were subjected to EDX analysis to check the calcium/phosphate (Ca/P) ratio. The second half of sample from each group subjected to atomic force microscopy (AFM) analysis to study the smear layer removal and nanostructural changes. Statistical analysis was done using ANOVA and Chi-square test. RESULTS: The AFM images showed no difference in the elimination of smear layer. The quantitative analysis using AFM showed EDTA group had significantly higher surface alteration than chitosan. EDX analysis showed that the Ca/P ratio of root dentine in EDTA group is significantly lower than chitosan group. CONCLUSION: Chitosan is an effective chelating agent with less alteration in radicular dentine.

Effect of 5% Chlorine Dioxide Irrigant on Micro Push Out Bond Strength of Resin Sealer to Radicular Dentin: An In Vitro Study.

INTRODUCTION: Chlorine dioxide (ClO2) has been recently investigated as a possible root canal irrigant due to its broad spectrum of antimicrobial action, tissue dissolution and smear layer removal properties. Literature is scarce on the effect of chlorine dioxide irrigation on the resin sealer dentin bond strength. AIM: To compare 5% chlorine dioxide (ClO2) with or without Ethylene Diamine Tetra Acetic acid (EDTA) with 3% Sodium hypochlorite (NaOCl) and EDTA combination as endodontic irrigants on the adhesion of AH Plus sealer to radicular dentin using micro- Push out Bond Strength (µPBS) test. MATERIALS AND METHODS: Forty freshly extracted central incisors were decoronated and randomly divided into four groups based on the different irrigation regimes followed during irrigation: Group I - 3% NaOCl + 17% EDTA, Group II - 5% ClO2 + 17% EDTA, Group III - 5% ClO2 and Group IV - Saline, and canal enlarged till Protaper F3. All the samples were obturated with F3 gutta-percha cones using AH Plus sealer and sectioned perpendicular to long axis to obtain 1mm thick slices from the middle and coronal portions for µPBS measurement in universal testing machine followed by assessment of failure pattern under stereomicroscope. Data was analysed using One-way analysis of variance (ANOVA), Bonferroni and t-test. RESULTS: Bond strength values were in the following order: Group I>Group II>Group III>Group IV, with no statistically significant difference amongst experimental groups on intergroup comparison, except with saline. The µPBS values were more in coronal third than middle third in all specimens, with no statistical significant difference. Mode of failure showed mixed patterns in all experimental groups except saline. CONCLUSION: In the present study, the bond strength values of ClO2 were comparable with conventional NaOCl and EDTA combination and hence, ClO2 can be considered as an effective alternative endodontic irrigant.

Comparison of fracture resistance of simulated immature teeth with an open apex using Biodentine and composite resin: An in vitro study.

AIM: To evaluate the fracture resistance in simulated immature teeth that had been backfilled using composite resin and Biodentine after using Biodentine as an apical plug material immediately and after 3 months of aging. MATERIALS AND METHODS: Sixty extracted human maxillary central incisors were simulated in an immature open apex. The roots of all the specimens were then standardized to a length of 10 mm and canals were instrumented to obtain the radicular dentin thickness around 1.5 mm. All the specimens were then randomly divided into three groups of twenty teeth each. Group I (control) - 4 mm apical plug of Biodentine backfilled with thermoplasticized gutta-percha. Group II - 4 mm apical plug of Biodentine and then backfilled with ParaCore. Group III - completely filled with Biodentine. Ten samples from each group were randomly divided into two subgroups. In subgroup A: Specimens were stored for 1 week. In subgroup B: Specimens were stored in phosphate-buffered saline solution for 3 months and were subjected to universal testing machine. Statistical analysis was done using one-way analysis. RESULTS: No significant difference in fracture resistance between the groups was observed when tested immediately. After 3 months of aging, only Biodentine group showed a significant reduction in fracture resistance without significant reduction with other two groups. CONCLUSION: Biodentine group has shown a drastic reduction in fracture resistance after 3 months of aging, and hence cannot be recommended as a reinforcement material in immature teeth with thin dentin walls.

Spring-Loaded Transpatatal Arch with Turbo-V Springs for Correction of Severe Torsiversion.

OBJECTIVES: The aim of this case report is to introduce an appliance that can be used for correcting severe bilateral symmetric rotation (more than 900) ofsecondpremolars in adult patient. Appliance design and testing: This is a case report ofa 27-year-old female patient with permanent dentition having Class I malocclusion with bi-alveolar dentoalveolar protrusion defined by a severe bilateral rotation (more than 90-) of upper second premolars. Since it was a case of maximum anchorage, we decided to extract upper and lower arch first premolars, and the upper and lower arch were strapped with fixed orthodontic appliance with MBT 0.022 slot PEA brackets and then a spring-loaded transpalatal arch with turbo-Vsprings appliance used to correct severely rotated premolars. After 4 months, both the premolars were orthodontically brought into proper alignment. Circumferential supracrestalfibrotomy was planned to prevent relapse. CONCLUSION: Spring-loaded transpalatal arch with turbo- Vsprings appliance can be very effective for correcting severe bilateral rotation (more than 900) of premolar teeth.