2 ◊Page 1 IMPLANT TRIBUNE Dental Tribune Middle East & Africa Edition | 5/2018 Fig. 9: Surgical placement of LL67 implants Fig. 10: Scanbodies in situ Fig. 11: Tissue level implants Fig. 12: Crowns on printed model Fig. 13: Implant crowns in situ Fig. 14: Scanbodies with composite flow material to increase scan accuracy Fig. 15: Verification jig locked in situ to gain implant passivity Fig. 16: Createch framework fit surface Even with assisted surgery or guided surgery, there are sometimes certain restrictions that prevent us from achieving the most ideal implant placement, such as this case shown where posterior access in the second molar region was reduced, so achiev- ing the perfect parallel was extreme- ly difficult. There are fully guided systems avail- able that allow for absolutely pre- cise implant placement, but these ar fraught with complexities and should be reserved for experienced clinicians. The accuracy of surgical guides should not be used to make up for a lack of surgical competency however. There are many factors to be consid- ered when using surgical guides, in- cluding whether the guide is tooth- ,soft tissue- or bone-supported. Tooth-supported allows the greatest degree of accuracy. If tooth-supported, · are there win- dows in the guide that direct full seating of the guide? · are the teeth that support exact po- sitioning of the guide mobile? Any mobility adds a degree of inaccuracy. · is the guide made from a direct intraoral scan or a scan of a study model? If scanning a study model, is this an accurate stone model rep- resentation? Otherwise, there is the risk of poor seating and inaccuracy of the guide. Fig. 17: Finished screw-retained bridge in situ If soft tissue-supported, mobility completely negates any accuracy of the guide, so it should only be used for a pilot drill and then a more con- ventional surgical protocol adopted. If bone-supported, · raising of a very large surgical flap is likely. · it is very difficult to ensure accu- rate full seating of a bone-supported guide in the precise planned posi- tion and this relies upon external fixation. Once the implants are placed in situ and fully integrated, we then have a choice of conventional wet impression techniques versus digi- tal intraoral scanning. For the ma- jority of cases, intraoral scanning is extremely predictable and reli- able—more so than conventional techniques—with milled (and lately printed) models having excellent properties and less accumulation of processing errors. However, deeply placed implants relative to adjacent teeth with deep contact points are very difficult to scan and pick up. Straumann tissue level implants of- fer a very straightforward restorative platform to scan from. With greater numbers of implants and fewer teeth to act as reference points, intraoral scanning becomes less reliable—particularly across the arch—so we need to exercise caution and be aware of its limitations. We have used composite flow stuck to the soft tissue to increase reference points for our scanners, increasing their ability to stitch images more ac- curately together. With this in mind, we cannot assume the scan is accu- rate and any framework fabricated would be non-passive; therefore, we must use other methods to verify the scan’s accuracy. We have found locking temporary abutments with- in a composite framework intraoral- ly the easiest and most reproducible way to do this. It then allows us to de- sign and mill a truly passive frame- work by Createch and a temporary acrylic bridge. Conclusion There are many opportunities to opt in and out of using technology regarding the digital implant work- flow. For anyone considering capital investment, the most important question to ask is, how will or can this improve the outcomes I provide to my patients, and then determine whether that warrants the expendi- ture. Too often are we subjected to sales pitches of the next biggest thing by company sales representa- tives and gadgets and gizmos end up by the wayside. Acknowledgements to Andy Morton and Ian Murch, the fantastic labora- tory technicians at Borough Crown and Bridge that I work closely with. Editorial note: This article was published in the 2/2018 issue of CAD/CAM_interna- tional magazine of digital dentistry. Dr Ross Cutts He is the principal dentist at Cirencester Dental Practice in Cirencester in the UK. He can be contacted at cuttsrg@aol.com.