The resin-dentin interface formed by two dentin adhesives, Optibond (OPTI, Kerr) and Scotchbond Multi-Purpose (SBMP, 3M), was ultramorphologically examined by transmission electron microscopy (TEM). Ultrastructural information from nondemineralized and demineralized sections was correlated. It was hypothesized that the different chemical formulations of the two adhesives would result in a different morphological appearance of the hybrid layer. Ultrastructural TEM examination proved that each of the two dentin adhesive systems was able to establish a micromechanical bond between dentin and resin with the formation of a hybrid layer. However, the interfacial hybridization process that took place to produce this resin-dentin bond appeared to be specifically related to the chemical composition and application modes of both systems. OPTI consistently presented with a hybrid layer with a relatively uniform ultrastructure, electron density, and acid resistance. These three parameters were found to be more variable for the hybrid layer formed by SBMP. Characteristic of SBMP was the identification of an amorphous phase deposited at the outer surface of the hybrid layer. Although both adhesive systems investigated follow a total-etch concept, their specific chemical formulations result in different interfacial ultrastructures that are probably related to different underlying bonding mechanisms. The clinical significance of these morphological findings, however, is still unknown.

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The analysis of dental students' clinical production/participation has been used to assess whether a prospective graduate is capable of unsupervised and independent practice (that is, competent to perform that practice). This method and others have inherent biases that may not accurately reflect whether the student has mastered the associated concepts and techniques required for dentistry. The aim of this study was to assess an informatics system that assigned curriculum meta-tags with time-based relative educational value units (ReVUs) to each clinical procedure performed by Medical University of South Carolina (MUSC) students. The system has been used since 1998, but for this study the complete data sets for the MUSC graduating classes of 2007 through 2016 were mapped using microcompetency codes for the dental procedures. In total, 421,494 procedures were formatted and analyzed using software developed to aggregate disparate data sets from clinical activities into a common format for evaluation. The results showed that the ten classes (cohorts) were very consistent with cohort high ReVUs averaging 7,317.1 points, cohort mean ReVUs being 5,180.2 points, and cohort low ReVUs averaging 3,381 points. A detailed analysis of student effort by dental subspecialty found that preventive activities represented 13.4%, patient assessment 32.6%, periodontology 2.8%, restorative dentistry 16.3%, prosthodontics 21.9%, endodontics 6.7%, and oral surgery 5.7% of the total points in the clinical part of the curriculum. In this system, point thresholds can be easily generated to monitor students' progress towards competence for each defined competency and thus assess their progress towards acquiring the skills required for unsupervised, independent practice.

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Restoration of decayed teeth with tooth-colored materials that can be bonded to tooth tissue has been a highly desirable property in restorative dentistry for many years. Advantages of such an adhesive restorative technique over conventional techniques using non-adhesive metal-based restoratives include improved restoration retention with minimal sacrifice of sound tooth tissue for retention purposes, superior adaptation and sealing of the restoration margins in prevention of caries recurrence, improved stress distribution across the tooth-restoration interface throughout the whole tooth, and even reinforcement of weakened tooth structures. The dental adhesive technology is rapidly changing. An efficient resin bond to enamel has already long been achieved. Its bonding mechanism has been fully elucidated and has proven to be a durable and reliable clinical treatment. However, bonding to dentin represents a greater challenge. After the failures of a dentin acid-etch technique in imitation of the enamel phosphoric-acid-etch technique and a bonding procedure based on chemical adhesion, modern dentin adhesives are currently believed to bond to dentin by a micromechanical hybridization process. This process is developed by an initial demineralization of the dentin surface layer with acid etchants exposing a collagen fibril arrangement with interfibrillar microporosities that subsequently become impregnated by low-viscosity monomers. Although the development of such a hybridization process has well been documented in the literature, questions remain with respect to parameters of-primary importance to adhesive efficacy.