The evolution of digital dentistry and the development of a digital workflow has concentrated on digital planning with the use of Cone Beam CT scanning as well as using digital restorative tools to combine DICOM (Digital Imaging Communication in Medicine) and .stl (stereolithography) files to virtually plan, place and restore implants before using this plan to treat patients. The resulting benefits are reduced chair time, high precision and predictable aesthetic results often with immediate fixed provisional restorations available at time of surgery and corresponding high levels of patient satisfaction.
Intra-oral scanning to create digital ‘virtual impressions’ is also becoming more prevalent with the information being stored in the .stl file format. This information can be utilised by appropriate CAD/CAM (computer-aided design and computer aided manufacturing) software to design and manufacture a dental restoration (either by milling or 3D printing).
One area that is sometimes overlooked is the use of digital technology in occlusal analysis and adjustment of the restored dental implant. The following case study examines the occlusal management of a conventionally placed implant.
A 36-year-old male patient presented with a fractured upper left second premolar.
Figures 1a, b & c photographs and periapical radiograph showing fractured upper left premolar.
A treatment plan involving root extraction and a conventional implant placement and the use of a bone graft substitute was formulated. A C-Tech (Bologna, Italy) Esthetic Line (EL) implant was selected as the appropriate implant in this case for several reasons. These include a sub-crestal insertion protocol and a modulated thread design that allows for bone maintenance at the head of the implant, increased bone to implant contact mid-implant and an aggressive apical design to achieve good primary stability. This also makes the implant suitable for immediate implant placement postextraction. The implant also incorporates a Morse locking connection, bevelled shoulder and a platform switching design which all help to minimise and prevent bone loss.
The root was carefully extracted. Figures 2a & 2b Root extraction.
The site was then prepared in accordance with the C-Tech surgical protocols with sequential use of a locator drill, pilot and depth drills to create the appropriate osteotomy. In this case a 4.3mm EL implant was selected with a length of 11mm. Once placed, the implant had good primary stability so that it was suitable for immediate loading. A healing abutment was screwed to the implant and the gap between the implant and the alveolar bone was filled with an appropriate bone graft substitute, in this case, BioOss (Geistlich, Wolhusen, Switzerland). The patient was then seen by the prosthodontist who took a conventional impression post surgery to allow for same-day fabrication of a resin based provisional which was then delivered to the patient two hours later. The provisional crown remained in situ for a four-month period. At this time the provisional was removed and a C-Tech PEEK scan body was placed on top of the implant and the digital impression was recorded using the Carestream CS 3600 intraoral scanner (Carestream Dental LLC, Atlanta, USA). A definitive CAD/CAM Zirconia/ Porcelain restoration on grade 5 titanium base was then fabricated and delivered to the patient. Having fitted the definitive restoration, a high precision adjustment of the occlusion was undertaken utilising T-Scan (Tekscan Inc., Boston, USA) digital occlusal analysis. The advantage of a digital analysis of the occlusion over conventional articulating paper is that it can identify, very accurately, force and timing as well as location. This is very useful in implant dentistry as occlusion can be adjusted to ensure that surrounding natural teeth with the periodontal ligament absorb the bite forces, minimising those on the implant.
Developments in digital dentistry have concentrated on case planning and virtual implant placement allowing for guided surgery solutions in choosing the optimal position for a restorative led implant restoration. Conventional implant placement protocols remain valid options, with a determining factor being the position into which the implant will be placed. One area of the digital dentistry workflow that is receiving more and more attention is digital occlusal analysis and subsequent management of the occlusion with implants. The longterm prognosis of an implant restoration is enhanced if the implant can be protected from excessive occlusal load.