Acid resistance of CAD/CAM resin composites. Erosion-related tooth surface loss is closely related to acid exposure, such as contact with acidic beverages or disease-related reflux. As a result, dental restorations in affected patients are also exposed to acids, which indicates that the performance and longevity of a dental restoration is impacted by the acid resistance of the individually employed restorative materials. However, unlike for ceramic materials, the acid resistance of CAD/CAM resin composites is not commonly evaluated by the manufacturers, and no standardised test methods have yet been established. Against this background, the present in vitro study aimed to examine the long-term resistance of CAD/CAM resin composites (Brilliant Crios, Cerasmart, Grandio blocs, Lava Ultimate, Shofu Block HC) against three acidic media (tonic water, acetic acid, hydrochloric acid) as well as demineralized water and to investigate potential damage mechanisms. Changes in surface roughness (Sa) were detected by confocal laser scanning microscopy (CLSM), and changes in surface hardness were measured using Vickers hardness (HV). The damage mechanisms were analysed by scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS) and micro X-ray computer tomography (µXCT). For each material, few changes in either Sa or HV were identified for at least one of the different media; for Cerasmart, the sharpest deterioration in surface properties was observed. SEM–EDS revealed leaching of barium, aluminium, and titanium from fillers in a 2 µm zone on the rough but not on the polished surface of the specimen. Within the limitations of the current study, it can be concluded that polished CAD/CAM resin composites can be recommended for clinical use in patients with erosive conditions.

Introduction: Competencies in the clinical examination of patients with temporomandibular disorders (TMD) can be achieved by self‐instruction. This study aimed to identify the impact of the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) instructional video on the practical examination skills of undergraduate students.Materials and methods: One week prior to completing an objective structured clinical examination (OSCE) addressing the examination of patients with TMD, undergraduate students in their third year received either the DC/TMD manual (control group) or additionally watched the instructional video once (intervention group). After passing the OSCE, a feedback questionnaire was completed by the students.Result: Fifty undergraduates were recruited to take part in the OSCE prior to their first clinical course. The sum scores achieved in the stations were higher in the intervention group, but missed significance. Participants of the intervention group more often agreed that completing the OSCE stations was easy, which was significant for one station (P = .023). 95.8% of the participating students supported the implementation of the video in dental education.Discussion: Due to the conception of the study, the video was only presented once to ensure that the control group had no access to the medium at all. However, it might be interesting to investigate whether repeated watching of the video enhances its effect.Conclusions: Clinical competencies in the examination of TMD patients can be achieved by self‐instruction with the DC/TMD manual and instructional video. Watching the video for educational purposes was highly recommended by undergraduate students.

Verfärbungen von Schmelz und Dentin können das ästhetische Erscheinungsbild eines Menschen relevant beeinflussen. Anhand eines klinischen Fallbeispiels stellt der nachfolgende Artikel die prothetische Rehabilitation eines 20-jährigen Patienten dar, der sich aufgrund eines Traumas mit einer deutlichen Farbdiskrepanz am Zahn 11 vorstellte. Da mit einem internen Bleaching das gewünschte ästhetische Ergebnis nicht vollständig erzielt werden konnte, wurde der Zahn für die Aufnahme einer Restauration präpariert. Hierbei wurden zunächst möglichst minimalinvasiv verschiedene keramische 360°-Veneers (Schicht- dicke von 0,8 mm bis 0,9 mm) hergestellt. Als monolithische Werkstoffe wurden zwei klassische Silikat-, eine Lithiumdisilikat- und eine hochtransluzente Zirkoniumdioxidkeramik sowie ein indirektes Komposit verwendet. Es zeigte sich, dass bei dieser geringen Schichtdicke kein Werkstoff die Verfärbungen adäquat maskieren konnte. Deshalb wurde nach erneutem Substanzabtrag der Zahnstumpf zur Aufnahme einer Vollkrone (1,2 mm bis 1,5 mm zirkulär) vorbereitet und Kronen aus den gleichen monolithischen Werkstoffen wie zuvor verwendet. Die Kronen wurden mit einer individuell verblendeten Krone aus Zirkoniumdioxidkeramik (Referenz) verglichen. Auch nach zusätzlichem Substanzabtrag waren werkstoffabhängige Unterschiede im Maskierungseffekt festzustellen. In Bezug auf die Beurteilung des ästhetischen Gesamterscheinungsbildes war bei dem stark verfärbten Pfeilerzahn die individuell verblendete Krone den übrigen monolithischen Restaurationen überlegen. The discoloration of enamel and dentin often has a lasting negative impact on the esthetic appearance. The current clinical case report illustrates which results can be achieved by supply- ing a patient with restorations fabricated from translucent tooth-colored materials for a traumatically damaged and discolored anterior tooth. A 20-year-old patient sought dental care due to a severe discrepancy in color and shape of tooth 11. As internal bleaching did not reveal a satisfying esthetic outcome, consequently we decided to supply the tooth with a 360° veneer. For material comparisons, the restorations were fabricated from five different monolithic materials. The preparation was performed following the guidelines for 360° veneers, featuring a circular thickness of 0.9 mm. The selected materials included indirect resin composite (Grandio blocs LT, VOCO), feldspathic ceramic (VITABLOCS Mark II LT, VITA Zahnfabrik), leucite-reinforced glass ceramic (IPS Empress CAD LT, Ivoclar Vivadent), lithium disilicate ceramic (IPS e.max CAD LT, Ivoclar Vivadent), and zirconia with 5 mol% yttrium oxide (VITA YZ XT Multicolor LT, VITA Zahnfabrik). The materials were compared for the parameters profitability, esthetics, and patient satisfaction. With a thin layer thickness (0.8–0.9 mm circular), the tooth discoloration could not be adequately covered by any of the 360° veneers. After more extensive preparation, providing a circular thickness of the restoration up to 1.5 mm, all five monolithic materials as well as an additional individually veneered zirconium dioxide crown, serving as a reference, could achieve a satisfactory result. However, the overall esthetic appearance was completely rounded off by the individualized zirconium dioxide crown.