Aim: The aim of the present study was to evaluate the long-term clinical survival and success rate of veneered zirconia crowns with a modified anatomical framework design after 10 years in function. Materials and methods: In total, 36 zirconia crowns were fabricated for 28 patients. An anatomically modified framework design was developed. Crowns were inserted between 2008 and 2009. A follow-up of 19 patients with 28 crowns was conducted in 2020 to document mechanical and biologic parameters. Additionally, a modified version of the pink esthetic score (PES) was documented. Patient satisfaction was assessed using United States Public Health Service (USPHS) criteria. The success and survival rates were calculated using the Kaplan-Meier analysis. Results: After more than 10 years of clinical service, the survival rate of the zirconia crowns was 92.9%. Biologic complications occurred in 12% of the examined crowns, whereas technical complications occurred in 54%. Mostly, chippings (50%) and insufficient marginal gaps (50%) were observed. Most crowns were positively evaluated for more than one technical complication. Periodontal conditions with probing depths of up to 3 mm were comparable with measured values before crown delivery (73% to 75%). Most of the crowns had modified PES values of 10 or higher. Patient satisfaction was high. Conclusions: The modified framework design led to a high survival rate of the crowns but a relatively low success rate. High patient satisfaction and inconspicuous periodontal conditions were demonstrated. Biologic complications occurred far less frequently than technical complications. Keywords: all-ceramic crown, framework design, clinical study, chipping, complications

Die unmittelbare bakteriendichte koronale Versiegelung des Wurzelkanalsystems sowie die Herstellung der Kaufunktion sind nach einer adäquaten endodontischen Behandlung grundlegende Faktoren für den langfristigen Erhalt dieser Zähne. Bei der Auswahl der Restauration wird dem Faktor Substanzverlust neben den Parametern Zahntyp, Attachmentverlust und Kronen-Wurzel-Verhältnis sowie prothetische Gesamtbehandlungsplanung eine wesentliche Bedeutung beigemessen. Zusammengenommen bestimmen diese Faktoren die Entscheidung über direkte oder indirekte Restaurationen sowie über die Notwendigkeit der Verwendung eines Wurzelkanalstiftes. Die postendodontische Restauration sollte als integraler Bestandteil der endodontischen Behandlung angesehen werden und dementsprechend zeitnah erfolgen – idealerweise innerhalb von vier Monaten nach der Wurzelkanalfüllung. Keywords: Postendodontische Versorgung, wurzelkanalbehandelte Zähne, Wurzelkanalstifte, adhäsive Befestigung, forcierte Extrusion

Der Ersatz fehlender Zähne durch festsitzende zahn-/implantatgetragene Restaurationen in Form von Verbundbrücken bewegt Praktiker und Wissenschaftler bis heute und führt bisweilen zu Kontroversen. Im Rahmen der Entwicklung einer S3-Leitlinie war es das Ziel, durch eine Metaanalyse mit der Ermittlung von Überlebens- und Komplikationsraten von Verbundbrücken die bestehende Studienlage zu bewerten und Empfehlungen für die Therapie mit Verbundbrücken zu erarbeiten. Die Literatur wurde systematisch in gängigen Datenbanken durchsucht und strukturiert ausgewertet. Eingeschlossen wurden randomisiert-kontrollierte Studien sowie prospektive Beobachtungsstudien. Für die quantitative Auswertung wurden 7 Studien eingeschlossen. Ermittelt wurden Überlebensraten der Verbundbrücken von 90,8 % (95%-Konfidenzintervall [KI]: 86,4–93,8 %) nach 5 Jahren und 82,5 % (95%-KI: 74,7–88,0 %) nach 10 Jahren. Die Implantatüberlebensrate betrug 94,8 % (90,9−97,0 %) und 89,8 % (82,7−99,4 %) nach 5 bzw. 10 Jahren. Die in den Konsensusprozess der Leitlinie einbezogenen Studien zeigen, dass dreigliedrige Verbundbrückenrestaurationen in Form von rigide gestalteten Endpfeilerbrücken, insbesondere im Bereich der verkürzten Zahnreihe, eine adäquate Therapieoption darstellen und akzeptable 5- und 10-Jahres-Überlebensraten erreichen können. Keywords: festsitzender Zahnersatz, Hybridbrücke, Implantatprothetik, S3-Leitlinie, Verbundbrücke, zahn-/implantatgetragener Zahnersatz

Purpose: The aim of the present study was to measure the bond strength of adhesively luted glass-fiber bundles inside the root canal with respect to the application procedure in comparison to conventional solid glass-fiber posts. Materials and Methods: 104 human anterior teeth were endodontically treated, root filled and divided into 8 groups (n = 13). After post space preparation, fiber bundles consisting of 6 and 12 glass fibers, respectively, were luted adhesively with a multi-mode adhesive (Futurabond U; Voco, Cuxhaven, Germany) and a dual-curing composite (Rebilda DC, Voco) with the following application modes into the root canal: (1) direct application with tweezers, (2) distribution of the fibers using a spreader, (3) application of ultrasound after insertion of fibers. Two different solid posts (Rebilda DC, Voco; and DentinPost, Komet, Lemgo, Germany) were used as controls. Roots were sectioned into 6 slices per root (thickness 1 mm). Bond strengths were measured using thin-slice push-out tests for 3 slices 24 h after post insertion and for 3 slices per sample following thermocycling (TC) for 6000 cycles and storage in 0.9% NaCl for 6 months. Homogeneity of the slices was analyzed using a stereomicroscope and, for representative samples, micro-computed tomography (µCT). Results: Mean push-out bond strengths (MPa) were significantly affected by post system (p 0.0005) and location inside the root canal (p = 0.004) but not by application mode (p = 0.544) or TC (p = 0.098; repeated measurement ANOVA). Fiber bundles consisting of 6 (13.2 ± 4.7) and 12 fibers (14.5 ± 4.3) revealed bond strength comparable to that of Rebilda Post (13.67 ± 3.2) but significantly higher than that of Dentin Posts (8.7 ± 3.02). Inhomogeneities were detected among 35.5% to 43.1% of the fiber-bundle samples, irrespective of number of fibers and application mode, and among 24.4% to 27.3% of the solid posts (p = 0.010; chi-squared test). µCT revealed voids inside the composite bulk between the fibers as well as between composite and dentin of adhesively luted fiber bundles. Conclusion: Adhesively luted fiber bundles achieved bond strengths comparable to those of solid fiber posts for one investigated post type, and even higher values compared to another post type. Inhomogeneities were frequently detected irrespective of application mode. Keywords: root canal dentin, fiber post, fiber bundles, aging, adhesive luting

Objectives: The aim of this randomized controlled trial was to evaluate the impact of facebow registration on the occlusal parameters and oral health-related quality of life (QHRQoL) when remounting complete dentures (CDs). Materials and methods: Thirty-two patients with new CDs were included. Intraoral pin registration with gothic arch tracing was performed to record the horizontal jaw relation. CDs were duplicated into two cast models, followed by mounting each pair of cast models into an articulator according to a mean setting (Group 1) and using a facebow (Group 2). Occlusal static contact points and the number of teeth in contact were evaluated by a computer program (laboratory results). CDs were adjusted according to the randomization protocol of Group 1 and Group 2. After 3 (T1) and 84 (T2) days, the clinical static contact points and teeth in contact were counted. Statistical analyses were performed using the F-test and the bootstrapping method. Questionnaires of the German version of the Oral Health Impact Profile (OHIP-G49) were distributed before the remounting procedure at T0, and at T1 and T2. Results: Laboratory: The mean number of occlusal contact points was 6.06 (Group 1: mean setting) and 7.23 (Group 2: facebow), P = 0.13. The number of teeth with at least one occlusal contact was significantly higher in Group 2 (P = 0.027). Clinic: The mean number of teeth with at least one clinical contact point was slightly significantly higher in Group 1 (7.13 compared with 5.31 in Group 2; P = 0.042). Mean values of the OHIP-G49 sum scores decreased in both groups, from T0 (Group 1: 48.56; Group 2: 45.46) to T1 (Group 1: 31.43; Group 2: 43.20), and to T2 (Group 1 29.06; Group 2: 29.40), with a significant reduction in Group 1 from T0 to T1 (P = 0.012). Conclusions: Differences in occlusion occur when an arbitrary facebow is used, compared with a mean setting, when changing the vertical dimension in the articulator when remounting CDs. With regard to oral health-related quality of life (OHRQoL), patients clearly benefit from a remounting procedure. Keywords: complete denture, facebow, occlusion, oral health-related quality of life, remounting procedure, RCT

Purpose: The aim of this ex-vivo study was to evaluate the load capacity of direct or indirect endodontically restored maxillary central incisors with Class III defects, with or without glass-fiber posts. Materials and Methods: Seventy-two extracted human maxillary central incisors were endodontically treated and bi-proximal Class III cavities were prepared. Specimens were randomly allocated to six groups (n = 12): direct restoration with composite (C); direct restoration with composite and additional glass-fiber post (CP); ceramic veneer restoration (V), ceramic veneer restoration and additional glass-fiber post (VP), ceramic crown restoration (Cr), ceramic crown restoration and additional glass-fiber post (CrP). Specimens were exposed to thermomechanical loading (TML: 1.2 million cycles, 1 to 50 N; 6000 thermal cycles between 5°C and 55°C for 1 min each), and subsequently linearly loaded until failure (Fmax [N]) at an angle of 135 degrees 3 mm below the incisal edge on the palatal side. Statistical tests were performed using the Kruskall-Wallis and Mann-Whitney U-Test. Results: During dynamic loading by TML, one early failure occurred in group C, CP, and CrP. Subsequent linear loading resulted in mean fracture load values [N] of C = 483 ± 219, CP = 536 ± 281, V = 908 ± 293, VP = 775 ± 333, Cr = 549 ± 258, CrP = 593 ± 259. The Kruskal-Wallis test showed significant differences of load capacity between groups (p 0.05). Mann-Whitney U-test revealed significantly lower maximum fracture load values of group C compared to group V (p = 0.014), after Bonferroni-Holm correction. Non-restorable root fracture was the most frequent type of failure. Conclusion: Endodontically treated maxillary central incisors with Class III defects directly restored with composite are as loadable as indirect crown restorations. Compared to full-coverage restorations, less invasive veneers appear to be more beneficial. Additional placement of glass-fiber posts shows no positive effect. Keywords: all-ceramic crown, Class III restorations, direct composite restorations, endodontically treated teeth, indirect restoration, post and core, veneers

Purpose: To analyze the effects of ethanol for final post space irrigation and etching mode on the bond strength of fiber posts luted with a mild multimode adhesive (pH 2.3) as compared with a reference group using a self-adhesive resin cement (SAR). Materials and Methods: Human anterior teeth were endodontically treated. After post space preparation, the root canals were irrigated using 1% sodium hypochlorite (NaOCl) applied with passive ultrasonic irrigation, followed by either distilled water (control) or distilled water and ethanol 99% as final post space irrigation. Fiber posts were luted using Futurabond U in self-etch mode (FU-SE), Futurabond U in etch-and-rinse mode (FU-ER), or Futurabond DC (SE) in combination with a dual-curing core buildup material (Grandio Core, all VOCO); alternatively, posts were inserted using a self-adhesive composite cement (RelyX Unicem 2, 3M ESPE). Bond strengths were evaluated using push-out tests following thermocycling (TC) and storage in 0.9% NaCl for 3 months. Results: Mean push-out bond strengths (MPa) were significantly affected by the luting system (p 0.0005) but not by the irrigation protocol (p = 0.068; ANOVA), although a significant interaction between the factors "luting agent" and "pre-treatment" was observed. FU E&R (21.28 [4.34]) and RX (20.12 [7.32]) revealed significantly higher bond strengths compared to FU SE (15.9 [6.02]), whereas F DC (18.8 [6.9]) did not differ significantly from all other groups. Ethanol pre-treatment increased bond strength in the apical part of the root canal for all materials, with the exception of FU E&R. Conclusion: Mild multimode adhesives exhibit comparable mean bond strengths to a SAR cement within the root canal for luting fiber posts if applied in an etch-and-rinse mode. Using this approach, ethanol application has no positive effects on bond strength. Keywords: multimode adhesive, root canal dentin, root canal post, aging, adhesive luting

The restoration of endodontically treated teeth involves a difficult decision-making process, especially when it comes to more complex prosthetic rehabilitations. Regarding singletooth restoration, there are high-level requirements for the restorative components and the application of all necessary treatment steps to achieve the final restoration. So when is there a need for a single-crown restoration or when might a composite resin restoration also be sufficient? For the assessment of endodontically treated teeth as abutment teeth for prosthetic restorations, there are no clear guidelines beyond single-tooth restorations. The aim of this article is to compile important aspects of the restoration of endodontically treated single teeth, including more complex prosthetic reconstructions, based on the scientific literature. Keywords: core build-up, crown, postendodontic restoration, prosthodontic restoration, survival

Das Ziel der adhäsiven Rekonstruktion stark zerstörter endodontisch behandelter Zähne ist der Aufbau einer funktionellen Einheit aus Wurzelkanaldentin, faserverstärktem Wurzelkanalstift und direktem plastischem Stumpfaufbau. Die korrekte Anwendung sowie die Abstimmung aller Komponenten aufeinander scheinen gegenüber der Wahl des Befestigungssystems von übergeordneter Bedeutung für die Haftung im Kanal und somit den Behandlungserfolg zu sein. Darüber hinaus sollte die verbliebene gesunde Zahnhartsubstanz durch adhäsive und/oder mechanische Maßnahmen wie die Präparation eines 2 mm starken "ferrule design" bei einer Kronenversorgung maximal geschont und stabilisiert werden. Dies wird durch aktuelle klinische Studien belegt, die unter Berücksichtigung eines entsprechenden "ferrule design" für den Einsatz adhäsiv befestigter faserverstärkter Wurzelkanalstifte gute Ergebnisse zeigen. Keywords: Faserverstärkte Wurzelkanalstifte, adhäsive Befestigung, Vorbehandlung, Stiftoberfläche, Wurzelkanaldentin

Die Versorgung endodontisch behandelter Zähne bzw. deren Integration in eine prothetische Gesamtrestauration setzt komplexes Wissen voraus. Auf der Ebene des Einzelzahnes werden hohe Anforderungen an die beteiligten restaurativen Komponenten und die Umsetzung aller therapeutischen Einzelschritte hin zur definitiven Restauration gestellt. Im Hinblick auf den Einzelzahn ist die Frage spannend, wann eine Kronenversorgung wirklich notwendig oder ob vielleicht eine Kompositrestauration noch hinreichend ist. Bei der Bewertung endodontisch behandelter Zähne als Pfeilerzähne für prothetische Versorgungen über den Einzelzahn hinaus gibt es keine klaren Richtlinien. Der Beitrag soll wichtige Aspekte für die Behandlungsplanung bei der Versorgung des endodontisch behandelten Einzelzahnes und für dessen Einbeziehung in komplexere Restaurationen im Spiegel der wissenschaftlichen Literatur herausarbeiten. Keywords: Postendodontische Restauration, Krone, Aufbaufüllung, Pfeilerzahn, Überlebenswahrscheinlichkeit