[ZApprO versus ZÄPrO: results of a first comparative study]. / ZApprO versus ZÄPrO: Ergebnisse einer ersten Vergleichsstudie.

BACKGROUND: More than 60 years after the enactment of the first Licensing Regulations for Dentists (ZÄPrO), a new Licensing Regulations for Dentists, the ZApprO, was implemented in 2020. The aims of this study were to evaluate and compare the "Course in Technical Propaedeutics" (TPK) with the course "Dental Propaedeutics with a Focus on Dental Technology" (ZPDT), which are based on different legal foundations. METHODS: The following parameters were compared after completion of the courses: (1) theoretical and practical knowledge, (2) regular department-internal learner evaluation, and (3) special evaluation of learning conditions by the learners and (4) by the instructors. The theoretical and practical exams and the questionnaires were analyzed in terms of their test-statistical characteristics (difficulty, discrimination index, internal consistency). Group comparisons between TPK and ZPDT were conducted using t­tests for independent groups. RESULTS: Significant differences were only detected in the students' evaluation of their learning conditions, with theoretical and practical knowledge transfer being rated lower in the TPK than in the ZPDT. DISCUSSION: The comparable results of the knowledge assessments and the regular learner evaluation, triangulated with the comprehensive learner and instructor evaluation, allowed a broad assessment of both courses. The significant differences identified provide opportunities for optimization of the newly implemented ZPDT course.

The Ca(2+)-binding protein calretinin is selectively enriched in a subpopulation of the epithelial rests of Malassez.

During tooth development, the inner and outer enamel epithelia fuse by mitotic activity to produce a bilayered epithelial sheath termed Hertwig's epithelial root sheath (HERS). The epithelial rests of Malassez (ERM) are the developmental residues of HERS and remain in the adult periodontal ligament (PDL). Although the cellular regulation of the Ca(2+)-binding proteins parvalbumin, calbindin-D28k, and calretinin has been reported in the inner and outer enamel epithelia during tooth development, an involvement of Ca(2+)-binding proteins in the ERM has not so far been characterized. Among the three Ca(2+)-binding proteins tested (calbindin D28k, parvalbumin, calretinin), we have only been able to detect calretinin in a subpopulation of adult rat molar ERM, by using quantitative immunohistochemical and confocal immunofluorescence techniques. TrkA (a marker for ERM) is present in numerous epithelial cell clusters, whereas calretinin has been localized in the cytosol and perinuclear region of a subpopulation of TrkA-positive cells. We conclude that, in inner and outer enamel epithelial cells, Ca(2+) is regulated by calbindin, parvalbumin, and calretinin during tooth development, whereas in the ERM of adult PDL, Ca(2+) is regulated only by calretinin. The expression of Ca(2+)-binding proteins is restricted in a developmental manner in the ERM.