Practical Procedures in Implant Dentistry. Группа авторов

       Placement of implants in younger patients that are skeletally immature is contraindicated. Implants act like ankylosed teeth and hence lack the ability to erupt and compensate for changes in growth. This may lead to the implant submerging over time and may also interfere with the normal growth of the jaw. Individual assessment by serial cephalometric radiographs, one year apart, is needed to confirm that growth has truly ceased [6] prior to implant placement.

       In the elderly patient, there is no upper age limit contraindication for implant therapy. However, the elderly patient may not be able to undergo prolonged surgical procedures, is likely to possess more systemic health factors and have decreased ability to adapt to new prostheses, may have poorer oral hygiene practices, and may require longer healing times due to changes in bone and calcium metabolism which can potentially affect osseointegration.

       Nevertheless, the literature suggests that age does not have an impact on osseointegration of implants, nor survival of the implants after osseointegration.

       It has been documented that smoking may impair wound healing through the vasoconstrictive effects of nicotine, which may compromise tissue perfusion and vascularity. This also may reduce the tissue capacity to combat infection.

       Multiple studies demonstrate a significant relationship between smoking and higher failure rates of implants [2, 7, 8]. Bain and Moy [8] revealed that smokers had more than twice the percentage of implant failures when compared to non‐smokers (11.3 versus 4.8%). Two studies investigated the effect of smoking on initial healing of the implant [7, 9]. They showed smokers had a higher failure rate than non‐smokers, particularly in the maxilla.

       Bain [7] found a statistically significant difference between smokers and non‐smokers, as well as between smokers and those who underwent a protocol of cessation of smoking during the period of implant placement and initial healing. Under the protocol suggested by Bain, patients are advised to cease smoking for a minimum of one week prior to and at least eight weeks after implant surgery. The short‐term implant success rates were similar to those who had never smoked. However, long‐term heavy smokers should be informed about the reduced success rate, especially for maxillary implants.

       Osteoporosis has been defined as a decrease in bone mass and bone density with an increased risk and/or incidence of fracture. Currently there is no evidence to suggest that clinical diagnosis of osteoporosis affects all parts of the skeleton uniformly. Thus, a diagnosis of osteoporosis in other parts of the skeleton does not presume that the maxilla and mandible are affected. A systematic review [10] reports no evidence for a higher failure rate of dental implants in the osteoporotic patient.

       The mode of action of bisphosphonate and other osteoporosis‐related medications is to disrupt osteoclastic‐mediated bone resorption, and this may reduce bone deposition by osteoblasts with a reduction in bone resorption and bone turnover.

       Medication‐related osteonecrosis of the jaw is a potential complication with long‐term use of bisphosphonates and complex surgeries. The impaired bone healing may leave exposed bone uncovered by mucosa resulting in chronic pain, infection, bone loss, and possible pathologic jaw fracture. The risk is increased in IV infusion therapy of these medications, other comorbidities, duration of medication usage, and the complexity of surgery.

       In a postal survey, Mavrokokki et al. [11] estimated the risk of osteonecrosis of the jaw after dental extraction to be 0.09–0.34% with weekly oral alendronate (Fosamax) and 6.7–9.1% with IV formulations used for bone malignancy.

       The American Association of Oral and Maxillofacial Surgeons updated position paper (2014) on bisphosphonate‐related osteonecrosis of the jaws listed additional risk factors of corticosteroid use, diabetes, smoking, poor oral hygiene, and chemotherapy [12]. Their recommendations are as follows:For individuals on oral bisphosphonate for less than four years with no clinical risk factors, no alteration or delay in the planned surgery is necessary. It is suggested that if dental implants are placed, informed consent should be provided related to possible long‐term implant failure and the low risk of developing osteonecrosis of the jaws if the patient continues to take an antiresorptive agent.For those patients who have taken an oral bisphosphonate for less than four years and have also taken corticosteroids or anti‐angiogenic medications concomitantly, the prescribing provider should be contacted to consider discontinuation of the oral bisphosphonate (drug holiday) for at least two months prior to oral surgery, if systemic conditions permit. The antiresorptive should not be restarted until osseous healing has occurred.For those patients who have taken an oral bisphosphonate for more than four years with or without any concomitant medical therapy, the prescribing provider should be contacted to consider discontinuation of the antiresorptive for two months prior to oral surgery, if systemic conditions permit. The bisphosphonate should not be restarted until osseous healing has occurred.

       Current management is based on minimal evidence and expert opinion with an emphasis on prevention. Informed consent must be attained on possible risks and complications. Ongoing careful monitoring is essential when considering implant treatment for these patients.

       Radiation treatment may lead to oral effects such as xerostomia, hypovascularity, mucositis, fibrosis, and osteoradionecrosis.

       A systematic review by Colella et al. [13] reported similar failure rates for implants placed pre‐radiotherapy compared with those placed post‐radiotherapy: 3.2 and 5.4%, respectively. Implant failure rate was significantly higher in the maxilla (17.5%) compared with the mandible (4.4%), with all implant failures occurring within three years after radiotherapy and most within 1–12 months. No implant failures were reported when radiation dose was less than 45 Gy.

       The adjunctive use of hyperbaric oxygen therapy (HBO) has been suggested in the treatment of irradiated patients. HBO increases the blood‐to‐tissue oxygen gradient, improving the healing capacity of irradiated tissue by stimulating capillary growth and osteogenesis. Treatment consists of breathing 100% pressurised oxygen for approximately 90 minutes for about 20 sessions pre‐surgery and 10 post‐surgery. Esposito et al. [14] in a Cochrane review of HBO and implant treatment failed to show any appreciable clinical benefits.

       Ihde et al. [15] reported in a systematic review that implants placed in irradiated bone exhibited a two to three times greater failure rate compared with non‐irradiated bone, with doses above 50 Gy having a higher failure rate. No significant differences in failure rate were found with implants placed at various intervals, either before or after radiotherapy for a clinical recommendation to be made. However, implants placed in the maxilla were at least twice as likely to fail and no specific implant could be recommended based on survival data.