Comparative evaluation of pericervical dentin preservation and fracture resistance of root canal-treated teeth with rotary endodontic file systems of different types of taper - An in vitro study.

Aims: The aim of this study was to evaluate and compare the pericervical dentin preservation and fracture resistance of root canal-treated teeth with rotary endodontic file systems of different types of taper. Subjects and Methods: Thirty-two single-rooted human-extracted premolars were used. They were mounted in wax, and preoperative cone-beam computed tomography (CBCT) scans were taken with 11 × 8 Field of view (FOV). The evaluation of the pericervical dentin thickness was done at the cementoenamel junction level. After pre-CBCT, the 32 samples were divided into four groups (n = 8) - Group A: fixed tapered hand files, Group B: variable regressive tapered TruNatomy, Group C: progressive tapered ProTaper Gold, and Group D: fixed tapered HyFlex EDM. Following instrumentation, postoperative CBCT scans were taken to evaluate pericervical dentin thickness. Obturation was done and access cavity was restored with composite. Fracture strength was checked for all the samples using "universal testing machine" until fracture, and calculated in newtons (N). Statistical Analysis Used: Student's t-test and ANOVA test, along with Tukey's post hoc analysis, were used for comparing mean values between the groups, and P < 0.05 was considered statistically significant. Results: The results of this study showed that there is no statistically significant difference in preserving pericervical dentin with file system of different types of taper and fracture resistance between the groups. Conclusions: Within the limitations of the study, it was concluded that different types of file taper systems used for root canal preparation have no significant effect on the preservation of pericervical dentin and fracture resistance of teeth.

Comparative evaluation of genotoxicity and cytotoxicity of flowable, bulk-fill flowable, and nanohybrid composites in human gingival cells using cytome assay: An in vivo study.

Context: Biocompatibility is one of the major prerequisites for safe clinical application of materials. Resin composites release their components into oral environment following restoration which cause adverse reactions. Aims: To evaluate and compare the genotoxicity and cytotoxicity of flowable, bulk-fill flowable, and nanohybrid composites with glass ionomer cement in human gingival cells using epithelial-based cytome assay. Methodology: Sixty healthy patients with noncarious cervical lesions were selected and randomly assigned to four groups (n = 15): Group A, glass ionomer cement; Group B, flowable composite; Group C, bulk-fill flowable composite; and Group D, nanohybrid composite. Class V restorations were done in each group with the respective restorative materials. Samples of epithelial cells were collected from gingiva before (control) (T1) and after 10 and 30 days (T2 and T3) postrestoration and examined for the presence of micronuclei and other nuclear anomalies. Statistical Analysis Used: The results were subjected to statistical analysis using Friedman's test and Kruskal-Wallis test. Results: The highest level of cytotoxicity was noted at T2 time point with a significant decline at T3 time point. Least cytotoxic damage was exhibited by Group A followed by Group D. Highest cytotoxic effect was shown by Group B followed by Group C. There was no significant level of genotoxicity induced by any of the materials tested at different time points. Conclusion: There is significant cytotoxicity induced by the tested composite materials which had no long-term effects and no genotoxicity was induced by any of the restorative materials tested.

Canal transportation and centering ability of root canals prepared using rotary and reciprocating systems with and without PathFiles in cone-beam computed tomography-based three-dimensional molar prototypes.

BACKGROUND: It is important to use instruments that cause minimal changes in the canal path for root canal preparation. There is inadequate literature comparing rotary and reciprocating systems and hand files. No study used three-dimensional printed models to compare rotary, reciprocating, and hand files. AIMS: We aimed to assess the canal transportation and centering ability of WaveOne Gold, ProTaper Gold, and NiTi Flex K-file systems with and without glide path preparation. MATERIAL AND METHODS: Forty-nine resin models were randomly divided into Group I A - WaveOne Gold with WaveOne Gold Glider and Group I B - WaveOne Gold without glide path; Group II A - ProTaper Gold with ProGlider and Group II B - ProTaper Gold without glide path; and Group III A - NiTi Flex K-files with no. 10 stainless steel K-file and Group III B - NiTi Flex K-files without glide path. Pre- and postinstrumentation cross-sectional images at levels 3, 5, 7, 9, and 11 mm were compared. RESULTS: WaveOne Gold caused the least canal transportation and improved centering ability (P < 0.05). NiTi Flex K-files transported the canal more than others in the apical levels (3, 5 mm). Glide path creation reduced canal transportation and improved canal-centering ability. CONCLUSIONS: WaveOne Gold system has better centering ability and lesser canal transportation than ProTaper Gold and NiTi Flex K-file. Glide path creation reduced canal transportation and improved canal-centering ability.

Comparative Evaluation of Casein Phosphopeptide-Amorphous Calcium Phosphate-Fluoride Paste and Sodium Fluoride Mouthwash in the Prevention of Dental Erosion: An In Vitro Study.

AIM: To compare the efficacy of casein phosphopeptide-amorphous calcium phosphate-fluoride (CPP-ACP-F) paste and 0.2% sodium fluoride mouthwash in the prevention of dental erosion using profilometer. MATERIALS AND METHODS: The buccal surfaces of 36 premolar sound teeth were ground and polished to achieve a flat surface with silicone disks. Samples were allocated in three groups randomly. Group I was pretreated for 5 days four times a day with CPP-ACP-F paste. Group II was pretreated for 5 days with 0.2% sodium fluoride mouthwash four times a day. Group III remained as the control group without any pretreatment. In the next step, all the samples were exposed four times a day for 3 days to carbonated beverages. The samples were rinsed with saline after each erosive cycle and stored in artificial saliva. The profilometer was used to determine the surface loss. The data collected were evaluated using one-way analysis of variance (ANOVA) along with post hoc test. RESULTS: The erosion of group I (CPP-ACP-F paste) and group II (0.2% sodium fluoride mouthwash) was significantly less than that of group III (control group). The erosion in group II was significantly lower than in group I. CONCLUSION: Both sodium fluoride mouthwash and CPP-ACP-F paste are effective in the prevention of dental erosion. Sodium fluoride mouthwash shows higher reduction in dental erosion when compared with CPP-ACP-F paste. CLINICAL SIGNIFICANCE: This study contributes to the understanding of the efficacy of CPP-ACP-F paste and 0.2% sodium fluoride mouthwash in the prevention of dental erosion.

Effect of layer thickness on the elution of monomers from two high viscosity bulk-fill composites: A high-performance liquid chromatography analysis.

AIM: The aim is to evaluate the effect of different layer thickness on the amount of elution of monomers from two high viscosity bulk-fill composites after 24 h and 1 month storage in ethanol using high-performance liquid chromatography (HPLC) analysis. MATERIALS AND METHODS: Forty-eight samples prepared from two high viscosity bulk-fill composite resins; Tetric EvoCeram Bulk Fill and x-tra fil were divided into three groups (n = 8) based on their layer thickness, i.e., Group 1 (2 mm), Group 2 (4 mm), and Group 3 (6 mm) and were then subdivided based on their storage period. The analysis of the eluates was performed using HPLC unit. Statistical analysis was performed using One-way ANOVA, independent sample t-test, and paired "t" test at a significance level of 0.05 (P < 0.05). RESULTS: Increase in layer thickness resulted in increased amount of bisphenol A-glycidyl methacrylate (Bis-GMA) and urethane dimethacrylate (UDMA) elution for both composites, i.e., Group 3 > Group 2 > Group 1 and there was statistically significant difference among all the groups. Tetric EvoCeram Bulk Fill showed a statistically significant increase in amount of Bis-GMA and UDMA elution for all groups compared to x-tra fil. Furthermore, increase in storage period resulted in statistically significant increase in amount of Bis-GMA and UDMA elution for both composites, i.e., Group 1B > Group 1A, Group 2B > Group 2A, and Group 3B > Group 3A. The mean value of UDMA elution was higher when compared to that of Bis-GMA elution for both composites and there was statistically significant difference for all groups. CONCLUSION: Within the limitations of this in vitro study, it was concluded that increase in layer thickness resulted in increased amount of Bis-GMA and UDMA elution for both Tetric EvoCeram Bulk Fill and x-tra fil.

Evaluation and comparison on the wettability of three root canal sealers after three different irrigant activation techniques: An in vitro study.

BACKGROUND: Wettability of root canal sealers to the root canal wall plays a significant role in the attainment of a fluid-tight seal. AIMS: This study aimed to evaluate and compare the wettability of three different root canal sealers on the root canal walls after three different irrigant activation techniques using the contact angle meter. SUBJECTS AND METHODS: Thirty-six single-rooted mandibular premolars after decoronation and cleaning and shaping up to size #35 were randomly divided into three groups with 12 samples in each group (n = 12) based on the different activation techniques: Group I (passive irrigation with side-vented needle), Group II (manual dynamic agitation), and Group III (passive ultrasonic irrigation). Root segments were split longitudinally and were subdivided into three subgroups based on the root canal sealers tested with four samples in each subgroup (n = 4): Subgroup A (Tubliseal EWT), Subgroup B (AH Plus), and Subgroup C (Endosequence BC sealer). A controlled volume droplet of sealer was placed on each specimen and was subjected to the contact angle meter. STATISTICAL ANALYSIS: Data were statistically analyzed using the one-way ANOVA and Tukey's post hoc test at a significance level of 0.05 (P < 0.05). RESULTS: A statistically significant difference was seen among all the groups and subgroups with the highest contact angle value for Group III and Subgroup C and the least value for Group I and Subgroup A. CONCLUSIONS: Passive irrigation with side-vented needle and Tubli-Seal EWT showed better wettability on dentin.

A Scanning Electron Microscope Evaluation of Smear Layer Removal and Antimicrobial Action of Mixture of Tetracycline, Acid and Detergent, Sodium Hypochlorite, Ethylenediaminetetraacetic Acid, and Chlorhexidine Gluconate: An In vitro Study.

OBJECTIVES: The main objective is to evaluate the efficiency in removal of smear layer of mixture of tetracycline, acid and detergent (MTAD), sodium hypochlorite (NaOCl), ethylenediaminetetraacetic acid (EDTA) and chlorhexidine gluconate by scanning electron microscope (SEM) evaluation and also to evaluate the antimicrobial action of the same irrigants against standard culture strains of Enterococcus faecalis. MATERIALS AND METHODS: This study included 60 extracted permanent teeth with single root canal. The sample was categorized into five groups with 12 teeth in each group. Root canals were enlarged till size 40 with K-files. One group was kept as control and irrigated only with saline. Other four groups used 5% NaOCl as irrigant during instrumentation and MTAD, 5% NaOCl, 17% EDTA, and 2% chlorhexidine gluconate as final rinse. Teeth were split and examined under SEM. To test the antibacterial action, the zone of inhibition method using agar plates was used. Obtained data were statistically analyzed by SPSS version 17 (SPSS Inc., Chicago, IL, USA). RESULTS: MTAD and 17% EDTA removed smear layer from all regions of the root canals. About 5% NaOCl and 2% chlorhexidine gluconate were ineffective in removing the smear layer. The mean zone of inhibition formed by the irrigants was in the following order; MTAD (40.5 mm), 2% chlorhexidine gluconate (29.375 mm), 17% EDTA (24.125 mm), 5% NaOCl (22.125 mm), and saline (zero). CONCLUSION: MTAD showed high smear layer removal efficacy, but no significant difference was found to that of 17% EDTA. As the dimensions of the zones of inhibition showed, MTAD has got highest antibacterial action against E. faecalis, followed by 2% chlorhexidine gluconate, 17% EDTA, and 5% NaOCl. However, the exact correlation of in vitro study results to clinical conditions is impossible due to the variables involved.

Evaluation and comparison of the microhardness of enamel after bleaching with fluoride free and fluoride containing carbamide peroxide bleaching agents and post bleaching anticay application: An in vitro study.

AIMS AND OBJECTIVES: The purpose of the study was to evaluate and compare the microhardness of enamel after the application of anticay on bleached enamel with fluoride containing and fluoride free bleaching agent. MATERIALS AND METHODS: Twenty freshly extracted teeth decoronated and divided mesiodistally into two halves were randomly divided into five groups with 10 samples in each group. The enamel surface was treated as follows: Group 1 - no treatment, Group 2 - fluoride free bleaching agent, Group 3 - fluoride containing bleaching agent, and Group 4 - fluoride free bleaching agent followed by anticay application. The samples were subjected to indentation to test the microhardness using Vicker's hardness analyzer. CONCLUSION: Enamel microhardness significantly increased in samples where anticay was used after the application of bleaching agent.

A Confocal Microscopic Evaluation of the Dehydration Effect on Conventional, Resin Reinforced Powder/Liquid and Paste to Paste Glass Ionomer Luting Cements.

BACKGROUND: The purpose of this study was to evaluate the effect of dehydration of resin-modified glass ionomer powder/liquid system, resin-modified glass ionomer paste/paste luting cements in three different quantities and to compare them with a conventional glass ionomer luting cement using confocal laser scanning microscope. MATERIALS AND METHODS: A conventional glass ionomer (Group I), a resin modified powder/liquid system (Group II), and a resin-modified paste/paste system (Group III) were selected for the study. In Group III, there were three subgroups based on the quantity of material dispensed. 50 premolar teeth were selected and randomly divided among the groups with 10 samples in each. The teeth were ground flat to expose a flat occlusal dentin. A device was made to standardize the thickness of cement placed on the teeth. The teeth were stored in distilled water for 24 h and then longitudinally sectioned to examine the tooth dentin interface under a confocal microscope. The specimens were allowed to dehydrate under the microscope for different time intervals. The width of the crack after dehydration near the dentinal interface was measured at definite intervals in all the groups and analyzed statistically using Student's t-test. RESULTS: Conventional glass ionomer cement showed the maximum width of the crack followed by resin modified paste/paste system during the dehydration period. Resin modified powder/liquid system did not show cohesive failure. CONCLUSIONS: Conventional glass ionomer luting cement is more susceptible to cohesive failure when subjected to dehydration compared to resin-modified glass ionomer paste/paste luting cement. Among the luting cements, resin-modified glass ionomer powder/liquid system showed the best results when subjected to dehydration.

Intensive care unit delirium.

Intensive care unit (ICU) delirium is widespread and occurs in 20% to 80% of patients. It can be assessed with ICU-validated scoring tools. The most commonly used tools include the Confusion Assessment Method for the ICU and the Intensive Care Delirium Screening Checklist. Since ICU delirium is associated with increased morbidity and mortality, it is imperative that risk factors are identified and prevented. Risk factors include predisposing factors such as history of alcohol abuse, dementia, or hypertension and precipitating factors such as immobilization, oversedation, higher severity of illness, and use of certain psychoactive medications such as benzodiazepines. Pharmacologic treatment with atypical antipsychotics may be used to reduce the duration of delirium if prevention is not successful. However, because of the adverse effects associated with these treatments, close monitoring for side effects is warranted.

Novel role of NF-κB-p65 in antioxidant homeostasis in human kidney-2 cells.

Nuclear factor-κB (NF-κB) plays a role in inflammation. However, we recently reported an association between NF-κB and antioxidant enzymes in renal proximal tubules of exercise-trained rats, suggesting its role in antioxidant homeostasis (George L, Lokhandwala MF, Asghar M. Am J Physiol Renal Physiol 297: F1174-F1180, 2009). A direct role of NF-κB in antioxidant homeostasis in renal cells has not been elucidated and warrants investigation. Therefore, we examined whether NF-κB has a direct role in antioxidant homeostasis and redox balance in human kidney-2 cells overexpressing NF-κB-p65 and compared them with the cells overexpressing Nrf-2, a well-known transcription factor involved in antioxidant homeostasis. The ability of NF-κB-p65 to increase antioxidant enzymes, to reduce reactive oxygen species (ROS), and to rescue ROS-induced renal dopamine D1 receptor dysfunction, was studied. The transcription activity of NF-κB-p65 and Nrf-2, measured as luciferase reporter activity, increased in cells overexpressing these nuclear factors. The levels of mRNA and activity of glutathione peroxidase as well as the protein levels of superoxide dismutase-1 and glutamylcystein transferase were increased in cells overexpressing NF-κB-p65 and Nrf-2. Furthermore, the levels of ROS decreased and D1 receptor agonist SKF38393-mediated [(35)S]GTPγS binding (index of D1 receptor function) increased in the presence of hydrogen peroxide in cells overexpressing NF-κB-p65 and Nrf-2. These results suggest a direct role of NF-κB-p65 in antioxidant homeostasis, contributing to redox balance in renal cells.

Maxillary lateral incisors with two canals and two separate curved roots.

Variation in the roots and root canal anatomy seems to be the norm rather than an exception. For a successful endodontic treatment, a clinician should have a thorough knowledge of the internal and external dental anatomy and its variations. Maxillary lateral incisors usually exhibit single canal with a single root. In this case, clinical examination and radiographs clearly demonstrates the presence of two root canals with two separate curved roots. This case report emphasizes the need for attention during endodontic management of maxillary lateral incisors.

Exercise activates redox-sensitive transcription factors and restores renal D1 receptor function in old rats.

We have previously reported that age-associated oxidative stress via protein kinase C (PKC) increases D1 receptor (D1R) phosphorylation and causes D1R-G protein uncoupling in renal proximal tubules (RPTs) of old Fischer 344 rats. This results in reduced ability of D1R agonist SKF-38393 to inhibit Na+-K+-ATPase in RPTs of old rats. Here, we studied the effect of treadmill exercise on markers of oxidative stress, PKC, D1R phosphorylation, D1R-G protein coupling, and Na+-K+-ATPase activity in RPTs of adult and old rats. We found increased levels of malondialdehyde, a marker of oxidative stress, in RPTs of old rats, which decreased during exercise. Nuclear levels of nuclear erythroid-related factor (Nrf)-2 and nuclear factor (NF)-kappaB in RPTs, transcription factors involved in antioxidant enzyme gene transcription, increased in exercised old rats. This was accompanied by an increase in the activity and expression of antioxidant enzymes, superoxide dismutase and heme oxygenase-1. Age-related decrease in the levels of D1R mRNAs and proteins was attenuated during exercise. Furthermore, exercise in old rats decreased PKC activity and D1R phosphorylation and increased SKF-38393-mediated [35S]guanosine 5'-O-(3-thiotriphosphate) binding (an index of D1R-G protein coupling). SKF-38393 also caused inhibition of Na+-K+-ATPase in these animals. Also, exercise caused a decrease in proteinuria and increase in phosphaturia in old rats. These results suggest beneficial effects of exercise in terms of increasing antioxidant defenses, decreasing oxidative stress, and improving kidney function in general and D1R function in particular in aging. Both Nrf-2 and NF-kappaB seem to play key role in this phenomenon.

Exercise decreases oxidative stress and inflammation and restores renal dopamine D1 receptor function in old rats.

Recently, we reported that oxidative stress decreases D1 receptor numbers and G protein activation in renal proximal tubules (RPT), resulting in diminished natriuretic response to dopamine in old rats. We tested the hypothesis that exercise in old rats will decrease oxidative stress and restore natriuretic response to D1 receptor agonist, SKF 38393. Old (23 mo) rats were subjected to rest (sedentary) or to treadmill exercise followed by measurement of oxidative stress [malondialdehyde (MDA)], inflammation [C-reactive protein (CRP)], anti-inflammation (IL-10), antioxidant enzyme [superoxide dismutase (SOD)], and natriuretic response to SKF 38393. We found that MDA levels decreased and total SOD activity and Cu/ZnSOD protein increased in RPT of exercised rats. Exercise increased the nuclear levels of Nrf2 transcription factor (which binds to anti-oxidant response elements) in RPT. The levels of CRP decreased and IL-10 increased in RPT of exercised rats. Furthermore, exercise increased the basal bindings of [3H]SCH 23390 and [35S]GTPgammaS (indexes of D1 receptor number and G protein activation, respectively) together with D1 receptor and Galphaq proteins in RPT membranes. Moreover, SKF 38393 increased sodium excretion in exercised rats. Also, exercise decreased the levels of proteins in the urine of old rats. These results demonstrate that exercise decreases oxidative stress, inflammation, and proteinuria and increases anti-oxidant defense and D1 receptor function in old rats. Therefore, exercise may prove beneficial in preventing age-associated increases in oxidative stress, inflammation, and preserving kidney function, in general, and renal D1 receptor responsiveness, in particular.