Quality Resource Guide l Implant Placement by the General Dentist 5th Edition 5 www.metdental.com be used to plan implant position, and generate custom surgical guides. This digital treatment planning requires inputting data from intra-oral scanners, (an optical impression) and merging the files. The resultant surgical guides can precisely dictate the depth and direction of the osteotomy site. (Figure 8, 9) 3D printers are now being used to fabricate guides in the dental office. (Figure 10) Many offices have now gone to an entirely digital workflow, making traditional impressions, plaster casts, and hand fabricated surgical guides and even cast crowns techniques from the past. Surgical Technique Following an antiseptic mouth rinse, access to the surgical site is typically done by making crestal incisions, bisecting the zone of keratinized gingiva. Ideally, the implant abutment exits the bone through a region completely surrounded by keratinized tissue. If the surgeon is planning to place a healing abutment or temporary prosthesis the day of surgery, and if a broad area of keratinized gingiva exists, tissues punches may be considered as an alternative to a full flap. However, this “flapless” technique limits visualization, making the punch method best suited for more experienced operators. Most surgical protocols (all slightly different depending on the manufacturer) recommend marking the site of the implant with a small round bur and then preparing the osteotomy with implant burs of increasing diameter. It cannot be overstressed that all preparation of implant sites in the bone must be done under copious irrigation to prevent overheating. The use of burs that irrigate internally (through the bur itself) make cooling much easier and more predictable (Figure 1). Although dense cortical bone is preferable to the soft cancellous type for improved initial implant stability, it is easy to overheat, much like drilling in hard dense oak versus a softer pine. Implant burs, like any other dental drills, become dull with increased use, contributing to heat buildup. Burs should be discarded at the first sign of decreased cutting efficiency, with some companies advising one time use. The RPMs used during drilling and implant insertion is another variable that is carefully prescribed by the implant manufacturer. A useful technique during osteotomy preparation is taking intraoperative radiographs, leaving the drill in place. The angle relative to adjacent teeth as well as the distance from important structures can be visualized and possibly corrected prior to implant insertion. Following the completion of the recommended bur sequence, it is often helpful to measure the depth one last time before fixture insertion. This is especially important for implants in an esthetic region where depth of insertion is critical. The platform of the implant is ideally placed 2-3 mm apical to the CEJ of the tooth/ teeth the implant is designed to support. Having a guide splint fabricated with the ideal position of the prosthetic teeth aids tremendously in visualizing this. It often becomes obvious that some type of bone graft is needed prior to implant placement; otherwise compromises such as poor crown/ implant ratios or suboptimal esthetics will result (Figures 5, 6, 7). Surgical guides may also be fabricated with sleeves that mandate the exact angle of the twist drills (Figure 8, 9). The accuracy of these guides are generally very good if they are supported by adjacent teeth. However, those that rest on mucosa or bone often shift or slip during surgery, and as a result, the position of the implant may be different compared to the computer-aided plan. 23 Figure 5 Wax up of prosthesis shows ideal tooth position. Figure 6 Vacuum-created splint was created from a wax up. Hard and soft tissue deficiencies are obvious when splint is in position. Figure 7 Block bone graft is placed in region of deficiency. Figure 8 Surgical guide splint (with sleeves) in place. Figure 9 Surgical guide in use.