Please activate JavaScript!
Please install Adobe Flash Player, click here for download
ePaper created 2018-03-23, 14:21:22 | version 1.38.0
lab tribune Dental Tribune Middle East & Africa Edition | January-February 20152C > Page 3C By Dr. Scott D. Ganz, USA T he process of accumulat- ing patient information to determine which course of dental implant treatment should be considered can be described under the category of pre-surgicalprostheticplanning. The first step in patient evalua- tion involves conventional peri- 3-D virtual planning concepts for implant-retained full-arch mandibular prostheses: The bone reduction guide apical radiographs, panoramic radiographs, oral examination, and mounted, articulated study casts. These conventional tools allow the clinician to assess sev- eral important aspects of the pa- tient’s anatomical presentation, including vertical dimension of occlusion, lip support, phonetics, smile line, overjet, overbite, and ridge contours, and to obtain a basic understanding of the un- derlying bone structures. Theaccumulationofpreliminary data afforded by conventional diagnostics provides the foun- dation for preparing a course of treatment for the patient. How- ever, the review of findings is based upon a 2-D assessment of the patient’s bone anatomy and may not be accurate in the ap- preciation of the spatial position- ing of other vital structures, such as the incisive canal, the inferior alveolar nerve, or the maxillary sinus. In order to understand each individual patient’s pres- entation fully, it is essential that clinicians adopt an innovative set of virtual 3-D tools. Through the use of advanced imaging modalities, new paradigms have been established that, in the au- thor’s opinion, will continue to redefine the process of diagnosis and treatment planning for den- tal implant procedures for years to come. Without the application of computed tomography (CT) or lower radiation dosage cone beam computed tomography (CBCT), an understanding of the 3-D anatomical reality cannot be accurately determined, po- tentially increasing surgical and restorative complications. The utilisation of 3-D imaging modalities as part of pre-surgi- cal prosthetic planning can take several paths as demonstrated in the flow chart. The first involves acquiring a 3-D scan directly, without any prior planning or ancillary appliances. The scan process can be accomplished at a local radiology centre or via an in-office CBCT machine, now widely available. The scan itself can be completed within several minutes. Once the data has been processed, it can be viewed via the native software of the CBCT machine used and evaluated for potential implant recipient sites, followed by the surgical inter- vention. A second path requires the fabrication of a radiopaque scannographic appliance that incorporates vital restorative in- formation and will be worn by the patient during the acquisi- tion of the scan. In this manner, the tooth position can be evalu- ated in relation to the underlying bone and other important ana- tomical structures, such as the maxillary sinus or the inferior alveolar nerve. The scan data can again be visualised via the CBCT machine’s native software and a plan can be determined based directly upon the restora- tive needs of the patient. The scan data is formatted into a nonproprietary data interchange protocol referred to as DICOM (Digital Imaging and Commu- nications in Medicine). The DICOM data can be exported for use in third-party software applications that incorporatead- ditional tools to aid clinicians in the diagnosis and treatment planning functions. The use of interactive treatment planning has expanded dra- matically in the past ten years as computing power has increased exponentially. There are at least two paths that can be taken once a virtual plan has been estab- lished. The first allows the data to be assessed, providing impor- tant information to the clinician who will perform the surgical intervention free-hand based upon the software plan. This has been termed CT-assisted inter- vention by the author. The sec- ond path involves the fabrication of a surgical guide or template that is remotely constructed from the digital plan usually through rapid prototyping or ste- reolithography. This method has been described as CT-derived template-assisted intervention and is considered to be more predictable than any previous methods. The use of advanced imaging modalities for presur- gical prosthetic planning is es- sential for any type of implant surgical and restorative inter- vention, including single-tooth and multiple-tooth restoration, full-arch fixed and removable overdenture reconstruction. 3-D planning concepts for the mandible Regardless of the image acqui- sition process, there are four standard views that need to be fully appreciated in the diag- nosis phase. These include the cross-sectional (A), the axial (B), the panoramic (C), and the 3-D reconstructed volume (D) as seen in Figure 1. The ability to interact within these images dif- fers from software to software. It is the ability to visualise 3-D data with improved tools that empowers clinicians to assess Fig. 1. Regardless of the image acquisition process, there are four standard views that need to be fully appreciated in the diagnosis phase. These include the cross-sectional (A), the axial (B), the pano- ramic (C), and the 3-D reconstructed volume (D).(Image: Dr Scott D. Ganz) Fig. 2a-c Fig. 3a-b Fig. 4a-b Fig. 5a-b Fig. 7a-b Fig. 9a-d Fig. 6a-b Fig. 8a-b