Digital Workflows in Implant Dentistry

German O. Gallucci, Christopher Evans, Ali Tahmaseb, Daniel Wismeijer, Stephen Barter, Nikolaos Donos, Daniel Wismeijer, Stephen Barter, Nikolaos Donos

• Editorial: Quintessence Publishing
• Año: 2019
• ISBN:
  9783868674996
• Edición: 1
• Categoría: Medicine
• Categoría: Dentistry

The field of implant dentistry continues to grow both in terms of the number of practitioners placing and restoring implants and in terms of as well as patient demand for successful outcomes in as short a time as possible. The pace of technological changes and new offerings from implant manufacturers and allied industries are equally fast in their attempts to meet these demands, with a frequently bewildering array of potential solutions available to clinicians. This is never more so than in the field of digital dentistry, with hardware and software solutions for diagnosis, imaging, planning, surgery, impression-taking, and the computer-aided design and manufacture of intraoral prostheses.However, we must always remember our responsibility to ensure that our treatments are carried out safely and in the best interests of our patients. This new Volume 11 of the ITI Treatment Guide series continues the successful theme of the previous ten volumes: a compendium of evidence-based methodology in digital techniques and procedures for daily practice. Written by renowned clinicians and supported by contributions from expert practitioners, the ITI Treatment Guide Digital Workflows in Implant Dentistry provides a comprehensive overview of various technological options and their safe clinical application.

1	Introduction
	G. Gallucci

Fig 1 Digital dataset used for planning in implant prosthodontics. CBCT: Cone-beam computed tomography. DICOM: Digital imaging and communications in medicine. IOS: Intraoral scanner. EOS: Extraoral scanner. STL: Standard tessellation language (formerly stereolithography).

The present Volume 11 of the ITI Treatment Guide explores the advances in implant dentistry made by incorporating digital dental technology (DDT). In this context, current implant prosthodontic protocols are revisited to accommodate modern technology and techniques.

This volume begins by addressing the technology and the necessary tools for the incorporation of DDT in a digital workflow, along with the clinical steps required for data acquisition. This includes imaging by cone-beam computed tomography (CBCT), intraoral scanning (IOS), extraoral scanning (EOS), and facial scanning (FS). It then turns to the different software tools needed to manipulate the digital data. A section is also dedicated to the integration of DDT into patient care by merging different datasets to virtually reconstruct the patient’s orofacial anatomy.

An example dataset used in DDT for virtual implant planning incorporates several digital elements, as shown in Fig 1. Two main aspects of this dataset are the technology used for capturing orofacial structures in digital format and the software used to manipulate those digital files in order to perform virtual treatment planning, or to use computer-assisted design/computer-assisted manufacturing (CAD/CAM) technology.

1.1	Acquiring Digital Data

Different technologies are used to capture orofacial structures in a digital format. For instance, a CBCT unit is used to obtain a digital 3D rendering of the selected anatomical areas.

Chapter 2 describes in detail the imaging techniques and specifications for CBCT use in Implant Dentistry. While CBCT has the capability to capture most orofacial structures, it is mostly used to digitally replicate structures of higher density such as bone and teeth. A CBCT will produce a file in a format called DICOM (Digital Imaging and Communications in Medicine); this is a standard format commonly accepted in medicine.

CBCT images are often merged with IOS or EOS images obtained with a surface scanner. These types of scanners generally yield the generic STL file format (formerly known as Stereolithography format, now Standard

Tessellation Language format). STL files are native to the stereolithography CAD software used by 3D systems. Unlike DICOM files, surface scanners produce a 3D representation of the surface of a scanned object. For this reason, a more detailed 3D representation of the scanned anatomical structures can be obtained when STL files are matched with a DICOM file.

Chapter 3 describes digital intraoral and extraoral scanning techniques as well as the associated technology. In addition to intraoral and extraoral scanning, the tissues of the face can be captured by a facial scanner (FS) to produce an additional dataset that can be merged with DICOM and IOS/EOS STL files, the goal being to obtain a complete virtual representation of the patient.

The current state of face scanning and an overview of the currently available technology are presented in Chapter 4.

1.2	Manipulating Digital Data

Fig 2 Virtual planning software for implant prosthodontics. Grey: DICOM. Green: STL. Red: Proposed implant. White: digital prosthetic setup. – Top left window: Cross-sectional views. Top right window: Axial view. Middle left window: Tangential view. Bottom left window: 3D reconstruction. Bottom right window: Panoramic view.

Fig 3 Screenshot of a CAD screen for an implant crown. (Courtesy of Chris Evans.)

Different software packages are available that can process digital files such as DICOM and STL for the virtual planning of implant placement, the digital design of surgical guides, or the digital fabrication of implant-supported prostheses. These software packages are divided into two main groups: (1) virtual implant-planning software and (2) CAD/CAM software. These two digital platforms can also be integrated to facilitate the free exchange of information.

Virtual planning software is used to select the ideal implant type and plan the implant’s position in relation to the anatomy of the patient and the desired implant-prosthetic design. Fig 2 shows an example display of virtual planning software that has been used to plan an implant case.

Several planning steps are performed in this platform as follows:

1.Importing, segmenting, and aligning DICOM files

2.Setting the panoramic curve

3.Matching of DICOM and STL files

4.Digital tooth set-up (prosthetic planning)

5.Virtual implant selection and planning

6.Virtual abutment selection and planning

7.Virtual bone augmentation planning

8.Digital design of a surgical template for guided implant placement

9.Rendering a surgical protocol

10.Connectivity with CAD/CAM software

These steps are described in detail in Chapters 5 to 9.

In dentistry, CAD/CAM software is generally used for digital prosthodontics. Here, the main file format used is an STL file obtained via an IOS or EOS unit. Initially, the CAD side of the software is used to manipulate the STL file to design diagnostic models, implant abutments, a temporary implant prosthesis, and the final implant-supported prosthesis (Fig 3).

For implant-supported prostheses, the implant position is captured by an IOS or EOS image of a master cast using scanbodies (impression copings for digital surface scanning). These are geometric objects of known dimension (Fig 4) connected to the dental implant instead of the regular impression coping. The scanbody is usually constructed from PEEK material and has a dimension that can be recognized by the CAD software. Based on the scanbodies, the CAD software recognizes the implant type and spatial orientation allowing for the subsequent design of the implant prosthesis. CAD software packages offer an array of tools and commands for the virtual design of implant prostheses.

Once the CAD process is completed, a new STL file can be exported to various types of hardware to perform the CAM portion of the process. Implant-supported restorations can be manufactured by two main processes: additive or subtractive manufacturing. These steps are described in detail in Chapters 10 and 11.

Additive manufacturing (AM) is the process of joining materials to make objects from 3D model data, usually layer upon layer. Examples of additive 3D printing/manufacturing are:

1.Vat photopolymerization (digital light processing)

2.Powder-bed fusion (laser sintering)

3.Binder jetting (powder-bed and inkjet 3D printer)

4.Material jetting (multi-jet modeling)

5.Sheet lamination (selective deposition lamination)

6.Material extrusion (fused filament fabrication)

7.Directed energy deposition (laser metal deposition)

Subtractive manufacturing is a process by which 3D...