International Journal of Computerized Dentistry, 02/2009

Purpose: In this in vitro study, all-ceramic inlays were subjected to a static strength test. The material used in this case was Vita Mark II® ceramic (Vita-Zahnfabrik, Bad Säckingen, Germany). The goal of the study was to evaluate two different inlay preparations with differently designed ceramic inlays resulting from it, to determine which offered the greatest possible resistance in static fracture loading tests. Materials and Methods: Tooth 36 on the model, provided with a standard preparation with a level floor, served as the test object. Two inserts were produced: one with classical preparation pattern, the other with a modified shape of the cavity floor. In one inlay design, the cavity floor was designed according to the guidelines valid for all-ceramic inlay restorations; in the second inlay design, a differently shaped cavity floor was selected to exclusively meet the requirements of the ceramic material. Impressions were then taken, and inlays were designed and produced by means of CAD/CAM technology. Results: Lower fracture strength with mean fracture load values of ca 66.6 N was shown for traditional inlay preparations with a cavity floor segment designed as box. The mean fracture strength of the inlay design consisting of the same material with a hemispherical cavity floor segment was 84.9 (N), 27.5% greater. Conclusion: The question arises whether it is possible, independently of the ceramic used, to achieve an increase in strength by modifying the design of the inlay. Keywords: preparation design, FE analysis, inlay design

For the diagnosis of bone pathology, planning of complex implant-supported prosthetic restorations, and guaranteeing oral surgery that is as safe and free of complications as possible, a three-dimensional radiological display is frequently indicated. Cone beam computed tomography (CBCT), which can cover a large part of the indications of the dental and oral surgical spectrum, represents an alternative to computed tomography. Moreover, the method offers the advantage that it can also be used in the dental practice, taking the existing radiation protection regulations into account. This guarantees optimum patient and user friendliness, because referral to a specialized CT facility is thus no longer necessary in most cases. In the first 12 months of the trials of the Planmeca Promax 3D® at the Department of Dental Surgery and Radiology of the University Clinic for Oral and Maxillofacial Medicine in Graz, the overwhelming majority of referrals for CBCT (almost 90%) was concerned with the field of oral surgery and implantology. Oral surgical questions mainly covered aspects of wisdom tooth anatomy, position of impacted canines, premolars, and mesiodents, as well as cystic lesions. Diagnoses of the maxillary sinuses and the area of tooth preservation represented further indications. Apart from diagnostic purposes, the objective of the referrals was facilitating optimum preparation for the pending operation. In the area of implantology, this was combined frequently with pre- or post-augmentative three-dimensional digital therapy planning. CBCT showed good results in the display of hard tissue structures and can be integrated without difficulty in the daily clinical routine. Keywords: CBCT, CT, oral surgery, oral radiology, computerized implant planning, 3-dimensional diagnostics.

The continuing development of innovative surgical and prosthodontic techniques has led to a greatly increased interest in and demand for restorations on immediately loadable implants, due to the numerous clinical advantages offered by this treatment mode. By now, numerous clinical observations supported by histological studies have shown that dental implants placed in fresh extraction sockets with subsequent immediate loading result in clinical success.1 Software-assisted approaches to prosthetically driven surgery combined with CAD/CAM methods can result in highly esthetic and functional all-ceramic restorations for single missing teeth or more extensive edentulous areas using an immediate-loading protocol. The most important objectives in this respect are to reduce treatment times, prevent postextraction bone resorption, and preserve the residual periodontal tissues. Implant-supported restorations have become a frequently employed treatment method for the partially or completely edentulous jaw, well documented in long-term observations and histological studies of the osseointegration process.1-4 Numerous treatment protocols have been proposed and employed, depending on the number and distribution of implants used, to obtain a functional rehabilitation, using diagnostic templates during the restorative process to ensure a better axial alignment of the transmucosal units relative to the occlusal load.12 The choice of implant in terms of shape and diameter must be consistent with immediate functional loading with a provisional or definitive restoration, taking into account the effects and specifics of the occlusal loading situation as well as the need for conditioning the soft tissues. Primary stability, biological stability and the BIC (bone-implant contact) index all define the basic parameters of osseointegration, just as with the treatment modalities and osseointegration processes associated with conventional loading protocols.6-11 In this case report, the surgical procedure was driven by the subsequent restoration. We describe the chairside definitive restoration of a single missing tooth 3513 in a single visit by placement of a tapered, immediately loaded implant, a titanium/zirconia abutment, and an all-ceramic crown, including tollow-up and evaluation of the clinical result. Keywords: prosthetically guided surgery, immediate loading, CAD/CAM technology, all-ceramic restorations

In February 2008, the Lava™ Chairside Oral Scanner C.O.S. (Fig 1) was successfully launched by 3M ESPE (St Paul, MN, USA) in the United States. In German dental practices, the test phase started in October 2008. In Germany, the new intraoral scanner for direct digitization of teeth will be available in April 2009. The method of data capture of the Lava™ C.O.S. is based on the novel 3Din- Motion technology. This technology was developed by Brontes Technologies (Lexington, KY, US), which was founded by former employees of the Massachusetts Institute of Technology (MIT) and acquired by 3M in October 2006. First study results prove the reproducibly high precision of the Lava C.O.S.

Both pressing technology and CAD/CAM methods have proven themselves clinically for the fabrication of allceramic restorations. The advantages of the Cerec technology for the economic fabrication of all-ceramic bridges can be exploited by the use of burn-out blanks of polymer material. The milling process of very hard ceramics in the milling unit, which has some disadvantages, is replaced by the pressing process and makes the IPS e.max press material accessible to CAD/CAM users, primarily for extending the range of indications to splinted crowns and small all-ceramic bridges. Keywords: all-ceramic, CAD/CAM technology, pressing technique, lithium disilicate.