Cartilage formation by serial passaged cultured chondrocytes in a new scaffold: Hybrid 75:25 poly(L-lactide-ε-caprolactone) sponge

PURPOSE: This study was designed to determine whether multipled chondrocytes immersed in a new scaffold, 75:25 poly(L-lactide-epsilon-caprolactone) sponge coated with type I collagen (75-PLC scaffold), could be used to generate cartilage tissue in vivo and to evaluate the correlation between cartilage generation and the phenotype of the proliferated chondrocytes. MATERIALS AND METHODS: Rat chondrocytes were suspended in 75-PLC scaffold at a density of 1 x 10 7 cells/mL after proliferation in a monolayer for 1 (P1) to 4 passages (P4) and implanted in nude mice for 4 weeks. Cells were characterized by the expression of genes encoding type II collagen, aggrecan, and type I collagen by Northern hybridization, and consequently, the newly formed tissue was evaluated histologically. RESULTS: The expression of aggrecan messenger RNA gradually decreased with the passaged cultures; however, the expression of type I collagen messenger RNA increased with time. The cartilage formations in all specimens were found not only in P1 chondrocytes but also in P2 chondrocytes, although when P3 chondrocytes were grafted, approximately 50% of cartilage formation was still observed up to but not beyond P4. CONCLUSION: It is suggested that cartilage tissue is generated with cultured chondrocytes up to P2 but not beyond P4. Northern blot analysis is useful for the assessment of whether the cells are capable of regeneration.     

A strong sense of coherence promotes regular dental attendance in adults

OBJECTIVE: To investigate the relationship between the sense of coherence (SOC) and dental attendance pattern. It was hypothesised that the subjects with a stronger SOC have a more regular dental attendance. BASIC RESEARCH DESIGN: In the nationally representative sample including 8,028 persons aged 30, or more, 88% were surveyed. The questionnaire and home interview included information about socio-economic and demographic factors, behavioural and attitudinal variables, such as oral health behaviours (i.e. dental attendance pattern), and the SOC scale (12-item). Chi-square test, unadjusted and adjusted logistic regression models were used in the data analysis. PARTICIPANTS: The sample for this study consisted of 4,263, 30- to 64-year-old dentate, adults. RESULTS: Regular dental attendance was more common among those with a stronger SOC. Gender, education, family income and marital status, but not age, were related with dental attendance. The gender- and age-adjusted associations between the SOC and dental attendance pattern were found to be significantly stronger among those having high-, or middle level of education compared with those having a low education level. CONCLUSION: A stronger SOC is associated with regular dental attendance. This raises the possibility of achieving long-term positive effects on dental attendance in adulthood, if the SOC could be strengthened during adolescence.     

The pharyngeal mucosal, parapharyngeal, and retropharyngeal spaces

Mass lesions in the deep neck spaces cannot be examined directly but instead require sectional imaging examinations. This pictorial essay reviews cases of mass and/or mass-like lesions in the oral cavity and/or the pharyngeal region that were radiologically diagnosed at our department. The purpose of this paper is to introduce to oral radiologists several key points in the sectional imaging diagnosis of a variety of lesions of the pharyngeal mucosal space, parapharyngeal space, and retropharyngeal spaces. To help readers make full use of CT or MR image findings of lesions in these spaces, we provide actual images of common diseases that occur in either the oral cavity or the neck. By focusing on displacements of fat, vessels, muscles, and bony structures in each space, oral radiologists can narrow the range of possible differential diagnoses. Familiarity with not only the anatomy of these spaces but also with the diseases specific to them and, in turn, their radiological manifestations, can help oral radiologists reach an accurate diagnosis.     

An In Vitro Investigation of a Comparison of Bond Strengths of Composite to Etched and Air-Abraded Human Enamel Surfaces

PURPOSE: The purposes of the study were to measure the tensile bond strength of composite resin to human enamel specimens that had been either etched or air-abraded, and to compare the quality of the marginal seal, through the assessment of microleakage, of composite resin to human enamel specimens that had been either etched or air-abraded. MATERIALS AND METHODS: Thirty mandibular molar teeth were decoronated and sectioned mesio-distally to produce six groups, each containing ten specimens that were embedded in acrylic resin using a jig. In each of the four treatment groups, the specimen surfaces were treated by either abrasion with 27 or 50 microm alumina at 4 mm or 20 mm distance, and a composite resin was bonded to the treated surfaces in a standardized manner. In the two control groups the specimens were treated with 15 seconds exposure to 36% phosphoric acid gel and then similarly treated before being stored in sterile water for 1 week. All specimens were then subjected to tensile bond strength testing at either 1 or 5 mm/min crosshead speed. For the microleakage study, the degree of dye penetration was measured 32 times for each treatment group, using a neutral methylene blue dye at the interface between composite and either 27 or 50 microm air-abraded tooth structure or etched enamel surfaces. RESULTS: The mean bond strength values recorded for Group 1 (phosphoric acid etch, 5 mm/min crosshead speed) was 25.4 MPa; Group 2 (phosphoric acid etch, 1 mm/min), 22.2 MPa; Group 3 (27 microm alumina at 4 mm distance), 16.8 MPa; Group 4 (50 microm alumina at 4 mm distance), 16.9 MPa; Group 5 (27 microm alumina at 20 mm distance), 4.2 MPa; and for Group 6 (50 microm alumina at 20 mm distance) 3.4 MPa. An analysis of variance (ANOVA) demonstrated significant differences among the groups, and a multiple comparison test (Tukey) demonstrated that conventionally etched specimens had a greater bond strength than air-abraded specimen groups. No significant difference in dye penetration could be demonstrated among the groups (p= 0.58). CONCLUSIONS: Composite resin applied to enamel surfaces prepared using an acid etch procedure exhibited higher bond strengths than those prepared with air abrasion technology. The abrasion particle size did not affect the bond strength produced, but the latter was adversely affected by the distance of the air abrasion nozzle from the enamel surface. The crosshead speed of the bond testing apparatus had no effect on the bond strengths recorded. The marginal seal of composite to prepared enamel was unaffected by the method of enamel preparation.     

A preliminary survey of interprofessional education

The purpose of this article is to review the literature on interprofessional education (IPE) and report on a preliminary survey of the current status of interprofessional education in seven academic health centers (AHCs) that have schools of dentistry associated with them. There is wide variability in interpretation of the term "interprofessional," and many barriers to interprofessional education exist including already overcrowded curricula in health professions schools, lack of support from faculty and administration, and financial constraints. Based on interviews completed at the authors' home institutions, it was recommended that topics such as ethics, communication skills, evidence-based practice, and informatics could be effectively taught in an interprofessional manner. Currently, some academic health centers are attempting to develop interprofessional education programs, but most of these efforts do not include dental students. Of the seven AHCs investigated in this study, only two had formal interprofessional educational activities that involved students from two or more health professions education programs. Dental school participants in this study professed a strong interest in interprofessional programs, but many interviewees from other professional schools and AHC administrators perceived that the dental school was isolated from other schools and disinterested in IPE. Many health care setting models in the future will include dentists as part of an interdisciplinary health care team; consequently, it is important for dental schools to become an active participant in future interprofessional educational initiatives.     

Patient perceptions of professionalism in dentistry

The purpose of this study was to examine how patients perceived the professionalism of University of Minnesota School of Dentistry students, faculty, and staff. Professionalism is defined by the authors as an image that will promote a successful relationship with the patient. Patients within comprehensive care clinics were asked to assess physical attributes and behaviors of the dental care providers using a questionnaire. The patients read statements dealing with characteristics of the dental care providers and responded as to whether they agreed, were neutral, or disagreed with the statement. The surveyed population consisted of 103 males and 97 females, 64 percent of whom lacked insurance coverage. Fifty-one percent of the patients were between the ages of forty-four and sixty-nine, but the overall age distribution was dispersed over a range of eighteen to one hundred. Our research found that all dental care providers displayed a professional appearance as well as behavior. The attire of the dental care provider affected the comfort and anxiety levels of patients, as did first impressions of both students and faculty. Most patients reported that students and faculty displayed effective time management and used appropriate language during the appointment. Finally, hairstyle, makeup, and jewelry appeared to have little effect on patients' opinions of the various dental care providers.     

CASE STUDIES for Dentistry: development of a tool to author interactive, multimedia, computer-based patient simulations

Computer-based patient simulations have been used to enhance the dental curriculum since the 1980s. This article describes the development of CASE STUDIES for Dentistry (CSD), a patient case simulation building template, developed at Virginia Commonwealth University, with which authors who have no programming expertise can create realistic, effective, interactive multimedia patient simulations by entering their own information and images into a straightforward, fill in the blanks interface. This program was written with Authorware, by Macromedia Inc. Design considerations included emphasis on information collection and analysis, synthesis of collected information, hypothesis proposal and testing, diagnosis, and treatment planning. The program consists of easily accessible interfaces for both authors and students. Authors build simulated patients using typed-in text and their own images. Faculty can build computer-based simulated patients so that students can immediately practice what they learn in class within a simulated doctor-patient relationship. CSD allows building simulations ranging from simple to complex patients in multiple disciplines. Robust feedback and other features allow students to learn both process and content in a self-directed, interactive environment.