International Journal of Esthetic Dentistry (EN), 03/2009

The esthetic success of a dental treatment depends on the correct diagnosis, treatment plan and clinical and laboratory procedures. This clinical report describes a diagnostically based protocol for conservative preparations on anterior teeth for adhesively retained composite and porcelain restorations. The diagnostic additive waxup, periodontal esthetic crown-lengthening, direct acrylic mock-up, conservative preparations for ceramic laminate veneers, luting procedures, direct restorations with composite resin used for the esthetic rehabilitation of a patient presenting conoid lateral incisors, and an unsatisfactory class IV restoration in the left central incisor are presented. An accurate diagnostic and interdisciplinary approach is necessary for obtaining improved, conservative and predictable esthetic results in esthetically compromised areas, such as the anterior maxillary dentition.

The current literature suggests that the bone-condensing approach while performing internal sinus floor elevation may not be beneficial for the future implant site. Furthermore, even with refined procedures, a predictable and controlled infraction of the sinus floor prior to graft placement still seems to be technique sensitive. In this context, the present article presents a modified technique along with the use of parallel osteotomes devoid of any contact to the lateral osteotomy wall. Therefore, compression of the adjacent bone will be avoided and the tactility of the site for the surgeon will be preserved as the osteotome is solely in contact with the subsinus cortex.

In the present article, the advantages and disadvantages of three treatment options (clasp-retained removable partial dentures, tooth-supported telescopic retained partial dentures, and implant-supported/retained prostheses) are discussed. Furthermore the case of a 44-year-old woman with shortened and interrupted dental arches is presented. The treatment selected for the case is revealed, and the rationale governing the decision is discussed. The treatment sequence is then outlined and the final outcome is presented and discussed according to the literature.

In the second part of this two-part article about treatment planning (the first part was published in Eur J Esthet Dent 2009;2: 152-162 and of which described in detail the findings, the esthetic analysis, and the possible treatment options), the chosen treatment is presented and described in detail. In addition, the prognosis of the chosen treatment and of the other treatment options that would have been possible is discussed.

Objective: To test the effect of different veneering techniques on failure modes and the reliability of veneered yttrium oxide partially stabilized tetragonal zirconia polycrystal (Y-TZP) in a veneer/core/composite trilayer configuration subjected to 30- degree off-axis mouth-motion step-stress fatigue. Methods: CAD/CAM Y-TZP zirconia plates were veneered using a lost-wax press technique (IPS e.max ZirPress, Ivoclar Vivadent, test group press, n = 24) and a hand build-up technique (IPS e.max Ceram, Ivoclar Vivadent, control group layer, n = 24) (12x12x0.7 mm). After adhesive bonding (Alloy Primer and Panavia 21, Kuraray) to resin-based composite blocks (12x12x4 mm, Z-100), samples were stored in water for 7 days prior to fatigue testing. Trilayer specimens were mouthmotion step-stressed using three profiles (EL-3300, Bose/Enduratec), with a spherical tungsten carbide indenter (r = 3.18 mm) until cracks reached the veneercore interface. All flat-layer specimens were angled 30 degrees with respect to the loading axis, simulating posterior tooth cusp inclination. Step-stress profiles were determined from single-cycle load-to-failure tests (n = 3). Results: Single-cycle load-to-failure tests yielded 825 N for the test group press and 803 N for the control group layer. Irrespective of the applied veneering technique, Y-TZP trilayers failed from surface deep cone cracks reaching the veneercore interface. Radial fractures of the YTZP cores were not present. Weibull stress level probability curves were calculated (AltaPro, ReliaSoft). Similar reliabilities (0.54 test group press, 0.51 control group layer) were determined at 100,000 cycles and a 200 N load. Conclusion: After occlusion-like loading the step-stress fatigue reliability of pressed and layered veneering ceramics over Y-TZP cores was comparable. Fracture was limited to surface damage in the veneer layer. Failure modes were identical for both veneering techniques. Bulk fracture of the YTZP core material was not observed.

The aim of the study was to evaluate the marginal fit of different In-Ceram alumina ceramic cores manufactured by four different techniques. Four groups of four In-Ceram alumina core specimens (Vita), each 0.6 mm in thickness, were fabricated from a master die using four different techniques: Group SL, the slip-cast technique (In-Ceram system); Group CL, the copy-milling technique (Celay system); Group CR, a CAD/CAM system (Cerec inLab system) and Group WO, the electro-deposition dipping technique (Wol-Ceram). After the core specimens were fitted on the master die, they were scanned with the use of a microtomography device (1072 micro-CT, Sky- Scan). Datasets were processed by software (TView v1.1, SkyScan) and 10 vertical sections from each core were generated. On these microtomographic cross-sections the marginal gap (MG) and the absolute marginal discrepancy (MD) were measured in microscale (µm). The slip-cast and the electro-deposition dipping techniques presented the best results of MG with 22 µm and 35 µm, respectively (α5%). The CAD/ CAM system presented an MG of 55 µm. In addition, the slip-cast and the electro-deposition dipping techniques presented the best results of MD with 50 µm and 60 µm, respectively (α5%). The slip-cast technique and the Wol-Ceram system presented the best marginal fit, followed by Cerec inLab, which presented clinically acceptable results. Microtomography analysis seemed to be a reliable method of evaluating the marginal fit of dental restorations.