Effect of composite warming on shear bond strength.

Several manufacturers produce devices designed to warm composite resins used in restorative dentistry. Previous investigators have examined the effects of heating composite restorative resins prior to placement and polymerization. Heating has been reported to reduce viscosity, improve ease of placement, enhance monomer conversion, and reduce microleakage. The aim of the present study was to compare shear bond strengths of room temperature (22°C) and prewarmed (54°C) restorative composite resin. Extracted bovine mandibular incisors were sectioned sagittally and embedded in acrylic cylinders. Enamel was selectively etched with 37% phosphoric acid, rinsed, and dried. Self-etching primer was applied to both enamel and dentin. Self-etching adhesive was then applied and photopolymerized. Composite resin capsules were then divided into prewarmed and room temperature groups. Fourteen composite specimens prewarmed in an incubator were applied to the prepared enamel and dentin and photopolymerized. Fourteen room temperature composite specimens were likewise placed. After storage in water for 24 hours, all composite specimens were subjected to shear stress testing. The resulting data were analyzed with a t test (P = 0.05). There was no statistically significant difference between the shear bond strengths of the prewarmed and room temperature composite resin specimens. Warming does not appear to affect bond strength of composite resin bonded to both dentin and enamel.

Comparison of state dental radiography safety regulations.

The aim of this study was to compare and provide an overview of state policies on occupational exposure, dosimetry, collimation, patient protection, and the use of portable handheld X-ray machines in dentistry. State government webpages containing radiation protection rules and regulations were scanned. The contents were compared against current federal regulations established by the Nuclear Regulatory Commission (NRC) and the US Food and Drug Administration (FDA). They were further evaluated in light of current recommendations from the National Council on Radiation Protection & Measurements (NCRP) and the American Dental Association (ADA). Most states' regulations mirror the exposure limits set forth by the NRC and FDA. Nonregulatory recommendations regarding use of dental radiography are periodically put forth by the NCRP and the ADA. State and federal agencies often follow recommendations from these scientific organizations when creating regulations. Clinicians must be aware of their state's radiation protection rules, as variations among states exist. In addition, recommendations published by organizations such as the NCRP and the ADA, while not legally binding, contribute significantly to the reduction of radiation risks for operators and patients alike.

Effective use of e-grading in the dental simulation clinic.

The purpose of this article is to describe the development and implementation of a grading software system, accessible from any platform, that engages today's generation of students and replaces paper grading. Set up at one U.S. dental school in an all-access, anytime (24/7) web-based program accessed through tablets, the software allows for a comparison between students' self-grading and instructor grading. This comparison facilitates student-faculty interaction, promoting discussion and student learning. The software can also be used for practical examination grading in which blinded grading between instructors is possible. The data gathered can produce descriptive reports students can draw upon to encourage self-learning and guided learning, propelling students to a better understanding of critical principles as they progress through multiple psychomotor skill sets. Other reports generated by the software allow for instructor calibration, exporting of grades directly into the university grading report system, and visual analysis of trends within each class. In a post-course survey, students (56 percent response rate) and faculty (79 percent response rate) agreed that the electronic grading was more efficient and allowed more time for faculty-student interaction than the previous grading system, thus creating an environment more conducive to learning. Overall, the software has improved students' perception of enhanced kinetic skills, while facilitating administration of preclinical projects and practical examinations.

Effects of mixing technique on bubble formation in alginate impression material.

Previous studies have found that variations in mixing technique can influence the porosity content of alginate impression material. The aim of this study was twofold: determine whether bubble formation in alginate is influenced by the sequence of water/powder addition prior to mixing, and to compare 4 different mixing techniques. Manual spatulation, an automated spinning bowl, a centrifugal mixer and a vacuum mixer were evaluated for the resulting porosity in the set alginate. It was found that adding powder first, versus water first, made no difference in the bubble content using the 3 automated mixing techniques (P = 0.714). However, porosity was significantly less for powder-first trials using manual spatulation (P < 0.05). It was also found that surface porosity in the resulting impressions was significantly less for centrifugal and vacuum mixing when compared to manual spatulation, while internal porosity was significantly less for centrifugal mixing compared to all other mixing techniques (P < 0.05). The centrifugal mixing and vacuum mixing techniques required the least amount of mixing time.

Bacterial contamination of clinical examination gloves.

Dental clinicians have been wearing examination gloves routinely during clinical procedures since 1986, when the CDC advised using them as part of standard personal protective equipment recommendations. Initially, latex was virtually the only material available for examination glove construction; however, in recent years, numerous other materials have been utilized for glove construction in response to the increased recognition of latex allergies among patients and dental health care workers. Examination gloves are marketed as "non-sterile" according to the FDA, which sets specific standards governing the manufacturing and distribution of these products. This study examined the prevalence of bacterial organisms present in a variety of freshly opened glove boxes. The same glove boxes were put into clinical use for a period of time and re-tested for the presence of bacteria. The quantity of bacteria present on gloves in the new boxes differed in comparison to the gloves that remained in the used boxes.