Customized procedure to display T-Scan occlusal contacts.

The virtual technique described in this article integrates reverse engineering and mandibular dynamics into dental computer-aided design and computer-aided manufacturing (CAD-CAM) systems. This technique aims to provide more objective information to the dental technician for the diagnosis, planning, and treatment phases. In order to carry out this protocol, the following devices, currently available in many practices, are necessary: an intraoral scanner, a T-Scan system, and some specific open reverse engineering software. By means of a virtual procedure, the T-Scan system detects the occlusal contacts, and the occlusal surfaces are obtained using an intraoral scanner. Once the alignment between the 3-dimensional occlusal surface and the T-Scan registration is carried out, the resulting contacts are projected onto the patient's occlusal surfaces; in this way, occlusal forces are obtained over time. The results obtained with this procedure demonstrate the feasibility of integrating different tools and software and the full integration of this procedure into a dental digital workflow.

Intraoral Digital Impressions for Virtual Occlusal Records: Section Quantity and Dimensions.

The purpose of this study was to locate the 3D spatial position mandibular cast and determine its occlusal contacts in a novel way by using an intraoral scanner as part of the virtual occlusal record procedure. This study also analyzes the requirements in quantity and dimensions of the intraoral virtual occlusal record. The results showed that the best section combination consists of 2 lateral and frontal sections, the width of this section being that of 2 teeth (24 mm × 15 mm). This study concluded that this procedure was accurate enough to locate the mandibular cast on a virtual articulator. However, at least 2 sections of the virtual occlusal records were necessary, and the best results were obtained when the distance between these sections was maximum.

Comparison of a conventional and virtual occlusal record.

STATEMENT OF PROBLEM: Conventional methods associated with many processes in dentistry are being replaced by methods that use digital technology. One of these processes is the making of occlusal records for the positioning of casts in a virtual articulator. Conventional interocclusal records and the articulator are being replaced by the virtual occlusal record and the virtual articulator. PURPOSE: The purpose of this study was to validate a virtual procedure to locate the mandibular cast in a 3-dimensional (3D) spatial position and to verify the occlusal contact points in reference to the corresponding maxillary cast on a virtual articulator. MATERIAL AND METHODS: The conventional procedure was carried out by locating 6 sets of casts in maximal intercuspal position without any interocclusal record. Then, the occlusal contacts were determined with articulating paper. Subsequently, the occlusal relationships and stone cast were digitized with a 3D scanner. The occlusal contacts were compared with photographs and by superimposing these on screenshots of the software. Finally, the deviation of discrete points on the mandibular cast was calculated, and all the points of the occlusal surface were compared point by point. RESULTS: This study analyzed the main variables of the virtual occlusal record by using 3 current reverse engineering software packages. The results show a mean deviation of 0.069 mm from the virtual occlusion procedure and a mean standard deviation of 0.011 mm from all the points of the occlusal surface. CONCLUSIONS: The main conclusion of this study was that the accuracy provided by a virtual occlusion procedure is greater than that of the traditional physical interocclusal record. Additionally, knowing the deviation of each alignment (best-fit operation or algorithm) is useful.

Comparison of the accuracy of a 3-dimensional virtual method and the conventional method for transferring the maxillary cast to a virtual articulator.

STATEMENT OF PROBLEM: The currently available virtual articulators fail to locate the digitized maxillary cast at the exact position in the virtual environment. Some locate the casts on a mechanical articulator with a facebow, and this position is then digitized for the virtual environment. PURPOSE: The purpose of this study was to compare the location of the maxillary cast on an articulator by using 2 different procedures: the conventional method and a virtual method. MATERIAL AND METHODS: With the conventional procedure, the kinematic axis of the participant was determined with an axiograph. The location of the maxillary cast in reference to this axis was then physically transferred to a Panadent mechanical articulator. By a virtual procedure, the same kinematic axis and the maxillary cast were transferred directly from the participant to the Panadent virtual articulator by means of reverse engineering devices. The locations obtained with both procedures were compared in a virtual environment with an optical scanner. By calculating the deviation at every point of the occlusal surface, the results obtained with this procedure were then compared with those of the conventional method. RESULTS: The mean deviation on the occlusal surface was 0.752 mm, and the standard deviation was 0.456 mm. CONCLUSIONS: The deviation between the procedures was sufficiently small to allow the methodology for orthodontic purposes. However, the accuracy of the virtual procedure should be improved so as to extend its use to other fields, such as orthognathic surgery or dental restorations, in which the clinical technique requires an articulator.

Improved digital transfer of the maxillary cast to a virtual articulator.

The clinical procedure described provides a quantifiable, repeatable, and reliable method of transferring the location of the maxillary dental arch from the patient directly to a virtual articulator (virtual facebow transfer) by means of reverse engineering devices to design a customized dental restoration. This procedure allows the dentist and the dental laboratory technician to work in a fully digital environment without having to mount stone casts on a mechanical articulator. In addition, specific suggestions are provided for designing the transfer device to enhance patient comfort during the data transfer process and reduce deviation.