A basic principle taught in dental school is that both systemic health and oral health are important factors that must be considered when any surgical procedure is performed. This principle covers almost all dental procedures because extractions, cavity preparations, gingivectomies, scaling and polishing, root planing and deep periodontal probing are invasive and surgical in nature. Obviously, site preparation and placing dental implants must be considered to be surgical procedures.

Systemic and Oral Health and Implants

Many systemic conditions have traditionally been considered to be important factors in the success, or failure, of dental implants, Table 4.1; the conditions are listed in alphabetical order.

Clinical studies suggest, however, that most systemic disease or conditions do not significantly increase the risk for implant failure to integrate. There are, however, exceptions to this general rule. Dental implant failure is a possibility for patients diagnosed with RA and diabetes, both of which cause the body to heal at a slower pace and have a higher risk of infection, as well as potentially compromising osseointegration.

The use of certain medications can also lead to dental implant failure, notably through poor osseointegration [1]. Recent research studies indicate that proton pump inhibitors (PPIs), commonly used for the treatment of gastric‐acid related disorders, may affect bone regeneration and the osseointegration process, causing an increased risk of deterioration of bone metabolism and impaired bone healing [2]. Likewise, it has been reported that patients using selective serotonin reuptake inhibitors (SSRIs) were found to be three times more likely to experience early implant failure than nonusers [3]. Although the findings did not reach statistical significance, they did suggest that SSRIs may lead to an increase in the rate of osseointegration failure.

Although the consensus is that systemic diseases should not be a problem regarding patient selection for implants, there is some evidence that the presence of diabetes mellitus does adversely affect dental implant outcomes [4]. Consequently, dentists should advise patients with medical issues to consult their physicians before undergoing any dental surgery procedure and, when in doubt, the dentist should personally consult with that physician prior to performing any surgical procedure. This is particularly true for patients on blood thinners and those suffering from hypertension.

Patients with the blood disorders, hemophilia¹ and polycythemia vera² as well as patients with heart conditions or those who have received arterial stents should always be of concern regarding implants. In the case of patients with polycythemia vera (i.e., a hematocrit >45 for males and >42 for females), anti‐clotting (anti‐platelet) medications such as hydroxyurea (Hydrea^®), aspirin and dipyridamole (Persantine^®) are often prescribed. Blood thinners are commonly prescribed for patients with heart conditions and to prevent strokes and heart attacks as well as to treat and prevent blood clots; these medications include aspirin, chlopidogrel (Plavix^®), apixaban (Eliquis^®), warfarin (Coumadin^®), rivaroxaban (Xarelto^®), and dabigatran (Pradaxa^®). Patients who have received stents are also placed on blood thinners for a short period. With patients experiencing any of these conditions or taking such medications, caution must be exercised before undertaking any surgical procedure, including site preparation for implant placement.

At first glance, the caution regarding the potential effects of bisphosphonate therapy on the success of dental implants might appear to be obvious. Bisphosphonates are pharmaceuticals that slow down or prevent bone loss and are recommended for strengthening bones. They are the treatment of choice for osteoporosis and Paget’s disease as well as a method of treating hypercalcemia and hyperkalemia, i.e., elevated calcium and potassium levels such as those in certain cancer patients. The therapeutic action of bisphosphonates is through inhibiting osteoclastic activity and promoting more effective osteoblastic activity. Although the optimal duration of bisphosphonate treatment is not known, apparently most benefits occur within the first five years of therapy. Long‐term bisphosphonate treatment, however, is reported to lead to atypical femur fractures and osteonecrosis of the jaw as well as esophageal cancer. Consequently, bisphosphonate treatment is customarily reviewed every three to five years and dentists should be cautious when considering dental implants for patients receiving bisphosphonates.

Oral health factors and conditions that may impact the success of dental implants are indicated in Table 4.2. We consider the primary predictors of implant failure are unresolved caries or infection, certain systemic diseases, smoking, advanced age, chronic periodontitis and poor bone quality. Of these oral health factors, the most important appear to be infection and bone quality.

However, as is discussed in later chapters, clinical predictors of implant success or failure can include implant location, short implants, acentric loading, an inadequate number of implants, parafunctional habits and absence/loss of implant integration with hard and soft tissues. Inappropriate prosthesis design also may contribute to implant failure.

Infection

Any oral infection is likely to cause problems with dental implants but the conditions that are of the greatest concern are indicated in Table 4.3.