Microwave disinfection of facial silicone prostheses, Part 1: Color stability.

STATEMENT OF PROBLEM: The choice of cleaning method is an important consideration for lengthening the serviceable time of facial prostheses as microbial organisms and biofilms could degrade facial prostheses and cause skin irritation. Whether microwave disinfection is a suitable cleaning method without degradation of the properties of a prosthesis is unclear. PURPOSE: The purpose of this in vitro study was to measure the color stability of 6 commonly used facial silicone elastomers after microwave disinfection over a simulated 1.5-year period. MATERIAL AND METHODS: Six different facial silicone elastomers: MDX4-4210, MDX4-4210/Type A, M511, A-2186, VST-50, and A-2000 were mixed with intrinsic silicone white opacifier (except for the control group) and subsequently combined with 4 silicone intrinsic pigment color groups: red (R), yellow (Y), burnt sienna (B), and a mixture of R+Y+B (M). The control group was a silicone elastomer without opacifier or pigment. Each of the 30 experimental groups consisted of 5 specimens (N=150). Five specimens were placed in a 250-mL Erlenmeyer flask filled with 160 mL of tap water. Seven flasks were then placed in a 660-W microwave oven. An exposure of 6 minutes was used according to the antimicrobial efficacy of microwave disinfection protocol on facial silicone prostheses with a final water temperature of 60 °C for 18 times (simulating 1.5 years of microwave disinfection with one 6-minute exposure monthly). A spectrophotometer was used to measure reflectance color change values (∆E). Color differences were calculated following CIELab (∆E*ab) and CIEDE2000 (∆E00) formulae. ∆E*ab and ∆E00 were statistically analyzed by a linear mixed effects model with 3 factors (silicone type, color shade, and time) using the R Statistical software program (α=.05). RESULTS: Both ∆E*ab and ∆E00 of all silicone elastomers studied were less than the visual perceptibility thresholds (∆E*ab<1.1 and E00<0.7) and were considered clinically acceptable (∆E*ab<3.0 and E00<2.1) after the 1.5-year simulation of microwave disinfection. Yellow and blue pigments had more effect on MDX4-4210 and M511, while red pigment had more effect on MDX4-4210, MDX4-4210/Type A, and M511 (P<.05). Nevertheless, the values were still below the perceptibility threshold (∆E*ab≤1.0 and E00<0.6). CONCLUSIONS: All 6 facial silicone elastomers maintained clinically acceptable color after 18 months of exposure to microwave disinfection.

Methods and timing of curricular integration in U.S. dental education in preparation for the Integrated National Board Dental Examination.

PURPOSE: To characterize methods, timing, faculty training, and barriers pertaining to curricular integration in preparation for the Integrated National Board Dental Examination (INBDE) at U.S. dental schools METHODS: Academic deans at 67 U.S. dental schools were emailed an online survey consisting of questions on the time frame and methods of curricular integration, faculty training, and barriers to curricular integration RESULTS: Approximately 86% of schools have implemented (∼39%) or will implement (∼61%) changes in curriculum in preparation for the INBDE. Curricular integration was completed in 3-4 years in most schools, with those schools with larger class sizes taking longer. While 56% of respondents reported avoiding a complete curricular overhaul, 79% reported course sequencing changes, adding, subtracting, or combining courses, and making some changes in existing courses. Curriculum committees had the most input in curricular changes, while individual instructors had the least influence. Sixty seven percent of respondents reported faculty being trained to teach in an integrated curriculum. Problem/case-based learning and clinical case presentations are being used more for incorporation of biomedical sciences in clinical curriculum; use of clinical examples was the most used mechanism to integrate clinical information in biomedical sciences curriculum. Eighty two percent of respondents indicated that lack of faculty time to prepare courses as the primary barrier for implementing an integrated curriculum. CONCLUSIONS: Our results show that most U.S. dental schools are implementing integrated teaching models to prepare their students for the INBDE. However, lack of faculty time and training need to be addressed for more successful curricular integration.

Assessment of Critical Thinking in a First-Year Dental Curriculum.

We studied how students in a Doctor of Dental Surgery (DDS) program perceived the importance of critical thinking and the extent to which critical thinking was perceived to be included in each of 25 courses of the first-year curriculum at The University of Texas School of Dentistry at Houston (UTSD). Sixty-nine of the 102 second-year students who were invited participated in an online survey. The survey had three parts, with all statements of each part evaluated on a five-point Likert scale ranging from strongly agree to strongly disagree. The first two parts assessed the importance of critical thinking in dental education and the criteria by which critical thinking in didactic curriculum can be measured. In the third part of the survey, students evaluated how well each course of the first-year curriculum achieved critical thinking. More than 90% of the respondents strongly agreed/agreed that critical thinking is essential to making clinical decisions. Students strongly agreed/agreed that 19 of 25 of the courses incorporated critical thinking. However, when students were asked to rank the top five of the 25 courses, only two courses (Human Biology, Neuroscience) emerged above all others in their weighted ranks, with another seven courses standing out, leaving 16 courses with low weighted rankings for their inclusion of critical thinking. In summary, students agreed on the importance of critical thinking in dental education, and on the criteria by which the incorporation of critical thinking should be measured in didactic and pre-clinical courses.