Cyclic Fatigue Resistance and Surface Roughness of Rotary NiTi Instruments after Simulated Clinical Use in Curved Root Canals - An Atomic Force Microscopy Study

Abstract Objective: To examine the cyclic fatigue resistance and surface topography of TruNatomy and ProTaper Gold nickel-titanium rotary files and evaluate the presence of alterations to surface topography following instrumentation in simulated curved canals. Material and Methods: Twenty-four nickel-titanium instruments, twelve each of TN and PTG file systems, were evaluated for cyclic fatigue resistance. The rotary files were rotated in a simulated root canal with standardized diameter, angle of curvature, and radius of curvature in a custom-made cyclic fatigue testing device until the instrument fracture occurred. The time to fracture for each instrument was recorded with a stopwatch; in seconds in each group. Fractured instruments were subjected to atomic force microscopy analysis measuring the average roughness and the root mean square values to investigate surface features of endodontic files. Mean values and standard deviation were calculated. Data were analyzed using the Mann-Whitney U test. Results: Time to fracture was marginally higher in PTG instruments than in the TN file systems. PTG files exhibited higher surface roughness when compared with TN files (p<0.05). Conclusion: TN file system had a higher cyclic fatigue resistance than PTG. Cyclic fatigue causing file breakage did affect the surface topography of the files. PTG files showed a higher surface porosity value than the TN files (AU).

Awareness and Practices of Minimal Invasive Dentistry amongst Dental Interns - A Descriptive Analysis.

The current approach to management of caries has evolved towards minimal invasive dentistry comprising of early diagnosis of incipient lesions, remineralization and conservative dental treatment with minimal intervention if required. Despite the focus of the dental curriculum on minimal invasive dentistry, not much of it is adopted into practice by the students. We wanted to assess the knowledge, attitude, and skills of minimal invasive dentistry amongst the dental interns of Dakshina Kannada district. MethodsThe data was gathered through an online questionnaire developed and validated by experts. ResultsA total of 244 dental interns responded to the online questionnaire survey. Majority was aware of the principles of minimal invasive dentistry mainly through lectures, although not many had practiced it. Fluoride treatment was the most recommended treatment for the prevention of caries. Although most of them agreed that caries risk assessment was effective, nearly half of them had never practiced it. A greater part of the respondents agreed upon the effectiveness of preventive measures and conservative modalities of treatment in the current day practice. ConclusionsDespite the awareness and knowledge of minimal invasive dentistry amongst the interns of Dakshina Kannada population, the practice of minimal invasive dentistry should be taught to the students and should be implemented in routine dental practice.

Reverse rotary instrumentation in the apical third of the root canal system: An scanning electron microscope analysis

The aim of the present study was to evaluate the efficacy of reverse rotary instrumentation in disinfection of the root canal at the apical third and qualitative confirmatory analysis using the scanning electron microscope (SEM). Subjects and Methods: Sixty single-rooted mandibular premolars were instrumented up to Protaper rotary file size F2 and contaminated with a known species of Enterococcus faecalis (ATCC 29212). The samples were then divided into three groups; Group 1: Experimental group-irrigation by agitation of 1% NaOCl with reverse rotary instrumentation; Group 2: Negative control-no irrigation; and Group 3 positive control-irrigation with 1% NaOCl using a 30-gauge needle. The colony forming units of all the groups were checked. SEM analysis of the samples was focused on the apical third to confirm the absence of E. faecalis biofilms. The data obtained were statistically analyzed by the Fisher's exact test and Pearson's Chi-square test. Results: Group I and III showed significant reduction in the growth of E. faecalis (P ≤ 0.001). SEM confirmed dense bacterial colonies in the Group II consistent with biofilm formation and reduction in bacterial colonies in Group I and II. Conclusion: Agitation with reverse rotary instrumentation in the apical third of the root canal along with 1% sodium hypochlorite proved effective in disinfection of the apical third of the root canal, which was further confirmed by scanning electron microscopic analysis. Hence, it can be used as an adjunct during rotary instrumentation in efficient cleansing of the root canal system in the apical third of the root canal system.

Correlation between Dental Caries and Salivary Albumin in Adult Indian Population– An In Vivo Study.

Aim: To analyze the relationship between dental caries, albumin in young adults between the age group of 20 to 30 years from South Canara district, Karnataka with varying caries experience as determined by their caries progression Methods and Materials: Eighty subjects from the outpatient department ranging between 20 to 30 years of age were screened and evaluated for their caries experience. Based on their level of caries a total of 80 subjects were selected and divided into four groups of 20 subjects each as follows; Group 1: enamel caries, Group 2: dentinal caries, Group 3: pulpal caries, Group 4: control group. The saliva was collected and analyzed for the presence of albumin levels in saliva and correlated to the same levels in serum. The statistical analysis was done using one way ANOVA test. Results: According to the present study there is an increase in the levels of caries with decrease in the levels of albumin. Serum albumin levels were also found to be decreased in caries prone individuals, hence showing a significant correlation between serum and salivary albumin levels. Conclusions: In the present study we found an inverse relationship between the levels of albumin in saliva and dental caries confirming the importance of albumin levels in inhibiting caries progression. Besides a correlation was also found between the levels of albumin in saliva and serum. Hence it can be used as a biochemical indicator in evaluating the susceptibility of caries.