Preoperative digital planning

Digital planning and preparation provide a high level of reliability in implant-prosthetic procedures. Preliminary virtual simulation of the surgical intervention can provide confidence and certainty to carry out the actual surgery with peace of mind.

By Dr Florin Cofar and Dr Eric van Dooren

Introduction

Every workflow begins with an information gathering exercise. If a digital workflow is followed, the information consists of data that can be processed by the software. Our prosthetics team employs a photo-video protocol to examine the aesthetic-functional relationship between the smile, dental situation, and face of the patient.

In addition to conventional photographic documentation and video sequences, we use digital volume tomography (DVT) and intraoral scans in the assessment of implant prosthetics cases. By merging all the information gathered, we obtain a “digital clone”.

These amalgamated data sets enable us to plan all steps in a virtual treatment suite; as if we were working on a clone of the patient. Here is an example of an implant prosthetic single-tooth restoration.

Fig. 1: Portrait image prior to the intervention
Fig. 2: DVT data set in the software programme

Creating a digital clone

The process begins by obtaining a high-quality portrait photograph, a DVT, and an STL file (Figs. 1–3). In the case presented here, tooth 12 can no longer be preserved and needed to be replaced with an implant prosthetic restoration.

Designing the prosthetic restoration forms the first stage of the implant planning sequence. In the present case, the shape of the existing tooth should be maintained. If an analogue workflow is followed, the premise for the implant is extraction of the tooth.

This scenario also forms the first step in the digital procedure described here, however, the tooth is “only” extracted virtually. We can extract the tooth digitally to design the future alveolar cavity (emergence profile) and generate an optimised emergence profile.

An alveolar model is required for (1) designing the drill template (navigated implant insertion) and (2) fabricating a temporary restoration or abutment prior to the surgical intervention. Only copied data files are used while the original data sets remain untouched.

Several methods can be employed to perform the virtual tooth extraction. In our opinion, the most effective approach is using the “Provisional Pontic” CAD process and to design the alveolar cavity to have an optimum shape.

Always work on two levels when executing this step: The working scan represents the first level, and the original scan with the tooth represents the second level in this scenario.

Continue reading here. Published in Dental Asia January/February 2021 issue.