Implant Surgery: Simple Healed Sites
The first step in planning implant surgery is to open a dialogue with the patient to identify the problem, as discussed in Chapters 4–6. After discussing costs, outlining the procedures involved and deciding upon the optimum treatment plan, the most important task is to perform a patient evaluation and collect essential data, Table 8.1.
Many dentists do not have ready access to a CBCT (cone beam computed tomography) system and, when weighing whether to embark on implant surgery, they often ask whether CBCT’s are necessary. The answer to this question is that No, they are not essential and, in fact, millions of implants have been placed without CBCT although there is no doubt that they can be very useful during treatment planning. One alternative to CBCT is bone sounding which, in most cases, can provide sufficient information for clinical decision making. However, as discussed below, it is important for the dentist to have available solid information on the bony parameters of the implant site. In the absence of a CBCT image, it is advisable to reflect a full thickness flap for the first 50 implant placements until the operator gains sufficient experience to readily visualize the bony architecture prior to surgery.
Replacing a missing or extracted single (free‐standing) tooth is the most common implant procedure performed. It is the most basic implant procedure in that there is no need for preparation of abutment teeth for a traditional bridge. Even although this procedure is surgical in nature, it is less invasive in that removal of enamel is an irreversible procedure. Bone and soft tissue can be regenerated through grafting procedures. Generally, the long‐term prognosis is better for a single implant than for a traditional bridge. Further, although the initial cost may be higher for a single implant, the long‐term cost is lower than for a traditional bridge. Also, replacing a single tooth will simplify possible future retention of prostheses such as FPD’s, RPD’s, and CD’s.
Table 8.1 Data collection for treatment planning.
CBCTa, if necessary
Models, if necessary
a CBCT: Cone beam computed tomography (also known as cone beam volume CT, C‐arm CT or flat panel CT) is an imaging technique consisting of X‐ray computed tomography where the X‐rays directed at the subject diverge to form a cone.
Table 8.2 Bone factors in implant planning (≥ denotes greater than or equal to, or simply “no less than”).
|Radiographic height of available bone (≥6 mm)
CT width, ridge mapping (≥6 mm)
Inter‐occlusal space (≥6 mm)
M‐D width (≥6 mm)
Systemic and Dental History
As discussed in Chapter 4, the following conditions are relative contra‐indications for implant surgery:
- Uncontrolled hypertension
- Uncontrolled diabetes
- IV bisphosphonates
- Periodontal disease (increases risk of peri‐implantitis)
Obviously, absence of active infection is strongly advised. Although smoking may not be a direct contra‐indication to implant surgery, advising the patient to avoid smoking for 48 hours post‐surgery may help reduce complications .
Most clinical factors impacting the decision to perform implant surgery are discussed in detail in Chapters 4–7. Nevertheless, it is useful to repeat them here as Tables 8.2 and 8.3 indicate the implant site considerations and treatment factors that must be decided on before surgery.
Regarding bone quality and the bony parameters surrounding the implant site, having a CBCT scan available does simplify matters because making the necessary measurements directly from the scan is very convenient. Further, a copy of the scan can be used during surgery to correlate the scan to the patient’s bony architecture.
Table 8.3 Treatment factors for dental implant placement.
|Need for bone graft (?)
Need for guided bone regeneration graft (?)
Need for a custom abutment (?)
Interim partial denture (?)
Table 8.4 Implant system selection.
The site criteria for a simple implant to be placed from the first molar and forward are indicated in Table 8.2 but are repeated here for emphasis:
- Bone width: ≥6 mm
- Bone height: ≥6 mm
- While the rule of 6 applies to the bone height as an absolute minimum requirement, it is highly recommended to have a 2 mm zone of safety when dealing with the inferior alveolar nerve. So, if placing a 6 mm implant in the posterior mandible, 8 mm of bone height would be needed.
- Inter‐occlusal space: ≥6 mm
If the bone criteria are not satisfied, then grafting or guided bone regeneration (GBR) may be necessary. Typical situations where grafting is necessary are discussed in Chapter 9.
The next decision is the choice of the implant system, Table 8.4.
The guidelines for deciding upon an implant choice are indicated in Table 8.5.
We are not advocating that all dentists must use implants with the listed criteria but rather that we have found that a tapered internal connection system (Fig. 8.1) to work the best in our multi‐facility group. With so many systems available, dentists should opt for the system that they are most comfortable with and that works best for them. Another factor, of course, is overhead and the various available systems differ in cost, which can be a factor in system selection.