Bücher und Digitale Medien

Purpose: To compare two different impression techniques for implants in totally edentulous patients. Materials and methods: A total of 38 patients had impressions taken both using plaster and splinted vinyl polysiloxane (splinted-VPS). Two casts per patient were generated and allocated as test (plaster) and control (splinted-VPS) cast groups according to a randomised cross-over design. One of the two casts from each patient was randomly selected as master cast according to a parallelgroup design and used to fabricate the definitive prosthesis. Outcome measures were implant and prosthetic success rates, complications, marginal bone level (MBL) changes, patient satisfaction, chair time required to take the impressions, inter-implant discrepancy between the casts, sulcus bleeding index (SBI) and plaque score (PS). Results: In total, 76 impressions were taken in 38 patients. Two plaster impressions failed. Furthermore, 38 computer-aided design/computer-assisted manufacturing screw-retained complete-arch prostheses were fabricated onto the master cast (18 from plaster and 20 from splinted-VPS impressions) and the patients were followed up for 3 years after loading. No drop-out occurred and no implants or prostheses failed, accounting for a cumulative implant and prosthesis survival rate of 100% over the 3-year post-loading period. Plaster impressions yielded significantly greater patient satisfaction and shorter chair time. The discrepancy between the casts was 0.055 ± 0.067 mm (P = 0.931). Mixed model analysis revealed a significant main effect from both the implant number and the inter-implant distance, while no difference was found with regard to implant angulation. Five chip-off fractures of the porcelain veneer occurred in 5 of the 38 patients (3 in restorations fabricated onto the plaster cast group and 2 in the splinted-VPS cast group) with no effect from the type of impression on the prosthetic success rate (P = 0.331). However, all of the patients were functionally and aesthetically satisfied with their prostheses. Furthermore, mean MBL, SBI and PS showed no significant differences (P > 0.05) between the groups. Conclusions: The clinical outcome of plaster impressions for completely edentulous patients was found to be the same as that for splinted-VPS impressions. The intraoral pre-scan resin framework try-in can be avoided. Plaster impressions may be less time consuming and thus more comfortable for the patient, but sometimes may have to be repeated due to fractures. Schlagwörter: CAD/CAM, fully edentulous, implant impressions, optical scanning Conflict-of-interest statement: All materials used in this study were purchased by the authors and there were no commercial or institutional interests.

Purpose: To determine, by means of a non-destructive experimental procedure, the effectiveness of adhesive restorations in reducing the cuspal deflection of endodontically treated premolars, with or without root canal fiber posts. Materials and Methods: The cuspal deflection of ten sound, intact maxillary premolars was evaluated. A loading device induced deformation by axial force (ranging from 98 to 294 N) applied on the occlusal surface of teeth while laser sensors registered the amount of deflection. Once tested, teeth were endodontically treated and the marginal ridges were removed. The teeth were randomly divided into two groups and restored with: group 1) dual curing adhesive, flowable composite, and microhybrid composite; group 2) the same materials associated with root canal glass fiber post and composite cement. The cuspal deflection test was repeated with the same protocol after restorative procedures, allowing a direct comparison of the same samples. Statistical analysis was performed using ANOVA at a significance level of 0.05. Results: Different average cuspal deflection was detected in the two groups: composite resin with post insertion resulted in lower deformation compared with composite alone. Mean deflection ranged from 3.43 to 12.17 µm in intact teeth, from 14.42 to 26.93 µm in group 1, and from 15.35 to 20.39 µm in group 2. ANOVA found significant differences (p = 0.02). Conclusion: Bonded composite restorations with fiber posts may be more effective than composite alone in reducing the cuspal deflection in endodontically treated premolars in which the marginal ridges have been lost. Schlagwörter: fiber post, cuspal deflection, resin-based composite (RBC) restoration

Der wissenschaftliche Fortschritt bei der adhäsiven Zahnmedizin hat zu konservativeren Techniken geführt, mit denen man - direkt und indirekt - ästhetische Probleme im Frontzahnbereich lösen kann. In diesem Artikel werden nur indirekte Techniken erörtert. Sie sind in komplexen Fällen, in denen es schwierig ist, die harmonische Zahnform und -farbe wiederherzustellen, deutlich überlegen. Zunächst gehen wir auf die Literatur ein und geben einen Überblick über diese Technik. Dann werden die Indikationen und Vorteile im Vergleich zur direkten Technik begutachtet. Anschließend wird die Vorgehensweise Schritt für Schritt beschrieben - von der Behandlungsplanung zum Unterfüttern und Polieren der adhäsiv befestigten Restauration. Der langfristige Erfolg von Veneers hängt hauptsächlich von der Zahnpräparation ab. Sie sollte auf den Schmelz beschränkt bleiben, die proximalen Kontaktbereiche einbeziehen, den zervikalen Schmelzrand erhalten und die Inzisalkante einschließen, um die Stabilität des Veneers zu erhöhen und die korrekte Platzierung zu ermöglichen. Es ist zwar kein klinisches Follow- up verfügbar, wie wir es für die Keramikmaterialien kennen, aber die Kunststoffkomposite der jüngsten Generation weisen interessante Eigenschaften auf. Sie sind widerstandsfähig gegen mechanische Belastung, haben eine ausgezeichnete Ästhetik und, was am wichtigsten ist, sie können intraoral repariert werden, ohne dass die physikalisch-chemischen und mechanischen Eigenschaften beeinträchtigt werden.

Scientific progress in adhesive dentistry has led to more conservative techniques, both direct and indirect, to solve esthetic problems in anterior teeth. This article will discuss only indirect techniques, which are clearly superior in complex cases in which it will be difficult to recreate harmonious tooth shape and color. After reviewing the literature and highlighting the properties of this technique, the indications and benefits compared to the direct technique will be assessed. This is followed by a step-bystep description of operative procedures, from treatment planning to relining and polishing of the cemented adhesive restoration. The long-term success of veneers depends mainly on the tooth preparation, which should be confined to enamel, involve proximal contact areas, maintain the cervical enamel margin, and incorporate the incisal edge to increase veneer resistance and enable correct placement. Although no clinical follow-up similar to that of ceramic materials is available, the latestgeneration resin composites offer interesting features. They can withstand mechanical stress, have excellent esthetic properties, and, most importantly, can be repaired intraorally without impairing their physicochemical and mechanical properties.