Im vorliegenden Fall werden die Diagnose und Behandlung eines ersten Unterkiefermolars vorgestellt, der einen vom Pulpakammerboden ausgehenden und bis zum approximalen Kavitätenrand verlaufenden Riss aufwies. Keywords: Cracked tooth, postendodontische Versorgung

Maintaining and restoring teeth exhibiting subgingival or even subcrestal defect extensions represent a common problem in daily practice. Such teeth are often deemed “unrestorable” due to a significant hard tissue loss and defect locations violating the biologic width. In order to achieve a sufficient 2-mm-ferrule design and reestablish the biologic width, both surgical crown lengthening and orthodontic extrusion have been suggested. However, surgical crown lengthening has a negative effect on the attachment level of adjacent teeth as well as esthetic disadvantages particularly in the esthetic zone. Therefore, orthodontic extrusion might be considered as a valid therapeutic alternative since gingival architecture is maintained. While most orthodontic appliances are too complex for daily application, forced orthodontic extrusion by means of the Tissue Master Concept might be a cost- and time-effective approach due to advances in adhesive and computer-assisted dentistry. This clinical case series illustrates the methodology of the rather straightforward Tissue Master Concept in specific clinical situations that may occur in clinical routine. Keywords:  forced eruption, orthodontic extrusion, tooth extrusion

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

In dieser Literaturübersicht soll die Fragestellung beantwortet werden, wie die Effektivität der schallaktivierten Wurzelkanalspülung im Vergleich zur Ultraschallaktivierung und zur konventionellen Handspülung zu bewerten ist. Analysiert wurden die hochfrequente Variante EDDY und eine Variante mit einer weitaus niedrigeren Frequenz, der EndoActivator. Als Parameter wurden die Reinigungswirkung (Entfernung von Debris, Smear Layer, organischem Gewebe, Kalziumhydroxid und Guttapercharesten), die antimikrobielle Effektivität, die Extrusion von Spülflüssigkeit und das Auftreten postoperativer Beschwerden nach Einsatz der Aktivierung herangezogen. Keywords: Wurzelkanaldesinfektion, EDDY, EndoActivator, Schall, Ultraschall

Background: Accurate implant placement in the bone is key to successful implant treatment. Once inserted, it can be difficult to correct the orientation of the implant axis, especially of a one-piece implant. Prosthetic-driven digital implant planning in combination with fully guided implant surgery can offer additional safety in such cases. Case presentation: The patient presented with a wide, edentulous interdental space extending from sites 13 to 16, which was to be restored with three one-piece zirconia implants supporting a zirconia fixed partial denture comprizing a cantilever to the mesial aspect. Digital planning based on DICOM (Digital Imaging and Communications in Medicine) and intraoral surface data was performed to ensure optimal positioning. Guided implant placement was executed using a contra-angle handpiece with special attachments and a compatible, sleeveless drill guide. Impressions of the implants for the final restoration were acquired using an intraoral scanner. Reflection-related errors were compensated for by using the given digital abutment geometry. The DICOM and STL datasets were superimposed and used as the basis for fabricating a monolithic zirconia restoration through a subtractive milling process. The final restoration was adhesively cemented. Conclusions: By using a prosthetic-driven implant planning strategy, it was possible to place the one-piece ceramic implants without an available implant manufacturer's guide-based solution. This was accomplished using a contra-angle surgical handpiece with special attachments and a compatible drill guide. This approach is particularly recommended for the placement of one-piece implants, which otherwise require irreversible abutment grinding for the adjustment of the implant axis orientation after placement. To increase the precision of the digital impressions of the implants, the ideal abutment geometry was imported and superimposed onto the scan data. The results demonstrate that the proposed method can dispense with the need for gingival retraction when acquiring impressions for implants of this type in the future. Keywords: ceramic implants, guided implant surgery, backward planning, intraoral scan, CAD/CAM, digital workflow, 

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

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

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

Purpose: To investigate the depth of nanoleakage of four luting agents for bonding fiber posts after thermomechanical fatigue. Materials and Methods: Twenty-four extracted human anterior teeth were endodontically treated, sectioned at the cementoenamel junction, and restored with fiber posts using four commercially available resin cements with the corresponding core buildup materials (n = 6): Panavia F 2.0/Clearfil DC Core Automix (Kuraray), Variolink II/Multicore Flow (Ivoclar Vivadent), RelyX Unicem/Filtek Z250 (3M ESPE), and Multilink Sprint/Multicore Flow (Ivoclar Vivadent). The specimens received all-ceramic crowns and were subjected to thermomechanical fatigue (1.2 million cycles). After cutting off the crowns, the roots were isolated with nail polish except for a 1-mm rim around the root canal, and immersed in 50 wt% ammoniacal silver nitrate solution for 24 h. The specimens were sectioned perpendicular to the long axis of the tooth into four slices, fixed, dehydrated, and processed for FE-SEM. Leakage was analyzed using backscattered FE-SEM and EDS. Results: The depth of nanoleakage was significantly affected by the factor resin cement (p 0.015; Kruskall-Wallis). Multilink Sprint resulted in significantly deeper penetration of silver particles than the other materials (p 0.05; Mann Whitney U-Test). Conclusion: Hybridization of the root canal dentin created by self-etching or etch-and-rinse adhesive systems demonstrated distinctive nanoleakage up to 0.8 mm, whereas the self-adhesive resin cement RelyX Unicem was able to prevent distinctive leakage at this penetration depth. However, none of the investigated luting systems would be able to hermetically seal the root canal if leakage occurred around the margins of the coronal restoration. Keywords: root canal dentin, resin cement, FE-SEM, nanoleakage, fiber post