Evaluation of chemical and morphological changes in radicular dentin after different final surface treatments.

The aim of this study was to evaluate the chemical and morphological effects of different lasers as a final surface treatment for endodontic therapy through energy dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM) respectively. Twenty-five maxillary canines were selected and instrumented with K3 system. Roots were randomly distributed into five groups (n = 5) according to the surface treatment: GI (distilled water), GII (NaOCl + EDTA), GIII (NaOCl + EDTA + 980 nm diode laser), GIV (NaOCl + EDTA+ 1,064 nm Nd:YAG laser), and GV (NaOCl + EDTA+ 2,780 nm Er, Cr:YSGG laser). Lasers were applied for 20 s and samples were bisected, exposing the treated surface and then subjected to elements quantification by EDS and morphological evaluation by scanning electron microscope (SEM). EDS data were submitted to ANOVA-two way, and SEM scores were submitted to two-way Kruskal-Wallis and Dunn's tests. The EDS analysis showed no difference for the chemical elements and Ca/P ratio between groups (p > .05). Statistical analysis showed more intense results for GV and less intense results for GI (p < .05). The GIII showed an amorphous organic matrix surface, while GV provided greater removal of intertubular dentin forming craters, and GIV promoted dentin fusion. The EDS method used in this study was not able to verify any chemical changes in root canal dentin; Nd:YAG, Er, Cr:YSGG, and 980 nm diode laser were capable of modifying the dentin morphology, correlating characteristics features for each one, which are essential clinical knowledge to establish the correct indication for each case. RESEARCH HIGHLIGHTS: EDS was not able to verify any chemical changes in root canal dentin after 980 nm diode, Nd:YAG and Er;Cr:YSGG laser treatments Nd:YAG, Er, Cr:YSGG, and 980 nm diode laser modified dentin morphology, correlating characteristics features for each one.

Effect of polyethelene oxide on the thermal degradation of cellulose biofilm - Low cost material for soft tissue repair in dentistry.

BACKGROUND: Bio cellulose is a byproduct of sweet tea fermentation known as kombusha. During the biosynthesis by bacteria cellulose chains are polymerized by enzyme from activated glucose. The single chains are then extruded through the bacterial cell wall. Interestingly, a potential of the Kombucha's byproduct bio cellulose (BC) as biomaterial had come into focus only in the past few decades. The unique physical and mechanical properties such as high purity, an ultrafine and highly crystalline network structure, a superior mechanical strength, flexibility, pronounced permeability to gases and liquids, and an excellent compatibility with living tissue that reinforced by biodegradability, biocompatibility, large swelling ratios. MATERIAL AND METHODS: The bio-cellulose film specimens were provided by the R.P Dressel dental materials laboratory, Department of Comprehensive Care, School of Dental Medicine, Case Western Reserve University, Cleveland, US. The films were harvested, washed with water and dried at room temperature overnight. 1wt% of PEG-2000 and 10wt% of NaOH were added into ultrapure water to prepare PEG/NaOH solution. Then bio-cellulose film was added to the mixture and swell for 3 h at room temperature. All bio-cellulose film specimens were all used in the TA Instruments Q500 Thermogravmetric Analyzer to investigate weight percent lost and degradation. The TGA was under ambient air conditions at a heating rate of 10ºC/min. RESULTS AND CONCLUSIONS: PEG control exhibited one transition with the peak at 380ºC. Cellulose and cellulose/ PEG films showed 3 major transitions. Interestingly, the cellulose/PEG film showed slightly elevated temperatures when compared to the corresponding transitions for cellulose control. The thermal gravimetric analysis (TGA) degradation curves were analyzed. Cellulose control film exhibited two zero order transitions, that indicate the independence of the rate of degradation from the amount on the initial substance. The activation energies for three transitions for cellulose and cellulose/PEG showed increasingly higher values for the transitions at higher temperatures. Key words:TGA, Bio-cellulose, PEG.

Design and Outcomes of a Comprehensive Care Experience Level System to Evaluate and Monitor Dental Students' Clinical Progress.

A Comprehensive Care Experience Level (CCEL) system that is aligned with Commission on Dental Accreditation (CODA) standards, promotes comprehensive care and prevention, and addresses flaws observed in previous Relative Value Units (RVU)-based programs has been implemented at the School of Dental Medicine, Case Western Reserve University since 2011. The purpose of this article is to report on the design, implementation, and preliminary outcomes of this novel clinical evaluation system. With the development of the CCEL concept, it was decided not to award points for procedures performed on competency exams. The reason behind this decision was that exams are not learning opportunities and are evaluated with summative tools. To determine reasonable alternative requirements, production data from previous classes were gathered and translated into CCEL points. These RVU points had been granted selectively only for restorative procedures completed after the initial preparation stage of the treatment plan, and achievement of the required levels was checked at multiple points during the clinical curriculum. Results of the CCEL system showed that low performing students increased their productivity, overall production at graduation increased significantly, and fluoride utilization to prevent caries rose by an order of magnitude over the RVU system. The CCEL program also allowed early identification and remediation of students having difficulty in the clinic. This successful implementation suggests that the CCEL concept has the potential for widespread adoption by dental schools. This method also can be used as a behavior modification tool to achieve specific patient care or clinical educational goals as illustrated by the way caries prevention was promoted through the program.

Dentistry students' perceptions about an extramural experience with a Brazilian indigenous community.

OBJECTIVE: The aim of the present study was to evaluate dentistry students' perceptions about an extramural activity designed to deliver dental care to an indigenous community. MATERIALS AND METHODS: This was a qualitative investigation involving 4 students of dentistry who had just had the experience of delivering treatment to indigenous Brazilian people. These students answered questions about the relevance of the experience to their personal and professional lives. We performed Content Analysis to data treatment and it was analysed by Social Representation Theory. RESULTS: Two social representations were reached: a) Being capable to promote oral health; b) Facing human feeling and respect each other. CONCLUSION: We concluded that participation in an extramural project improves the students' understanding of primary health care in dentistry. Such experiences help students develop a sense of cultural respect, comprehensive care, and to understand patients in their totality as social beings with their own values, beliefs, and attitudes regarding oral health care.