International Journal of Computerized Dentistry, 01/2009

Surveying intraoral structures by optical means has reached the stage where it is being discussed as a serious clinical alternative to conventional impression taking. Ease of handling and, more importantly, accuracy are important criteria for the clinical suitability of these systems. This article presents a new intraoral camera for the Cerec procedure. It reports on a study investigating the accuracy of this camera and its potential clinical indications. Singletooth and quadrant images were taken with the camera and the results compared to those obtained with a reference scanner and with the previous 3D camera model. Differences were analyzed by superimposing the data records. Accuracy was higher with the new camera than with the previous model, reaching up to 19 µm in singletooth images. Quadrant images can also be taken with sufficient accuracy (ca 35 µm) and are simple to perform in clinical practice, thanks to built-in shake detection in automatic capture mode. Keywords: Intraoral measurement, registration, accuracy, CAD/CAM, virtual model

Twenty years ago, Cerec was introduced to the dentalpractice as a completely new workflow. The restorationof a tooth with a ceramic inlay in one appointment wasan innovation that was followed with scepticism in thebeginning. Only after the first long-term studies werepublished, for example Reiss/Walther, did the break-through and recognition come from science and univer-sities. Since the market introduction of Cerec 1 in 1988,over 25,000 systems have been sold worldwide. We canassume that since its inception, more than 14 million Cerecrestorations have been placed. The initial scepticism towards the Cerec method has beenresolved. Many scientific publications have dealt with allaspects of ceramic restorations and have proven thatCerec results are at least as good as ceramic or goldrestorations from the dental lab. Eight years ago, in the wake of the Berlin Dentists Con-ference, the current Cerec 3 hardware was introduced tothe audience. Compared to the former editions Cerec 1and Cerec 2, Sirona had decided to separate the acquisi-tion unit from the milling unit.

The technical features of the new Cerec Bluecam greatly simplify the optical impression-taking process and allow the dentist to concentrate on the patient and on the clinical aspects of the procedure. The level of precision attained with the Cerec Bluecam compares very well with the results achieved with laboratory scanners. With Cerec Bluecam, digital impressions become a clinical reality even for laboratory-made indirect restorations.

Powder or spray? - An anachronistic question concerning "as well as" or else: Why do it at all? Twenty-one years of our own experience with the Cerec system make us think. Much has developed further, some things have been revolutionized, new dimensions have been opened up, and yet some things remain almost unchanged. The camera - previously only slightly modified - represents in its current form a new generation of optical measuring systems, as can be gathered from other articles. But what about powdering? Where do we stand today?

The new software for the Cerec system is a perfect companion for the Cerec Bluecam and the Cerec 3 camera. It has a completely new and redesigned 3D preview. Taking optical impressions for new users is now easier than ever and has all the features that the experienced user requires. The software indication spectrum includes: inlays, onlays, anterior crowns, posterior crowns, veneers and now also long-term provisional chairside bridges. The new milling preview shows precisely where the restoration in the selected block will be placed and how it will be milled.

During the past few years, the innovations and improvements of the Cerec system by Sirona have been mainly marked by progress in the software field (the most recent improvement being the introduction of the biogeneric inlay design function for occlusal surfaces). Now the world leader in dental CAD/CAM system has developed a new and completely redesigned recording unit. I was given the opportunity to test Cerec AC for several weeks. In addition to the new design, the very core of the Cerec AC - the new Bluecam 3D camera - is apt to excite both seasoned Cerec users and newcomers alike.

Cerec users today produce chairside inlays, onlays, veneers and crowns on the basis of a digital impression. Cerec Connect, Sirona's Internet portal, through which Cerec users can send digital models to the laboratory for production of the restorations, is now available for many further indications.