Planning General considerations Planning for<unk> s focuses on the general health condition of the patient, the local health condition of the mucous membranes and the jaws and the shape, size, and position of the bones of the jaws, adjacent and opposing teeth. There are few health conditions that absolutely preclude placing<unk> s although there are certain conditions that can increase the risk of failure. Those with poor oral hygiene, heavy smokers and diabetics are all at greater risk for a variant of gum disease that affects<unk> s called peri-implantitis, increasing the chance of long-term failures. Long-term steroid use, osteoporosis and other diseases that affect the bones can increase the risk of early failure of<unk> s. It has been suggested that radiotherapy can negatively affect the survival of<unk> s. Nevertheless, a systemic study published in 2016 concluded that<unk> s installed in the irradiated area of an oral cavity may have a high survival rate, provided that the patient maintains oral hygiene measures and regular follow ups to prevent complications. Biomechanical considerations The long-term success of<unk> s is determined, in part, by the forces they have to support. As<unk> s have no periodontal ligament, there is no sensation of pressure when biting so the forces created are higher. To offset this, the location of<unk> s must distribute forces evenly across the prosthetics they support. Concentrated forces can result in fracture of the bridgework,<unk>  components, or loss of bone adjacent the<unk> . The ultimate location of<unk> s is based on both biologic (bone type, vital structures, health) and mechanical factors.<unk> s placed in thicker, stronger bone like that found in the front part of the bottom jaw have lower failure rates than<unk> s placed in lower density bone, such as the back part of the upper jaw. People who grind their teeth also increase the force on<unk> s and increase the likelihood of failures. The design of<unk> s has to account for a lifetime of real-world use in a person's mouth. Regulators and the<unk>  industry have created a series of tests to determine the long-term mechanical reliability of<unk> s in a person's mouth where the<unk>  is struck repeatedly with increasing forces (similar in magnitude to biting) until it fails. When a more exacting plan is needed beyond clinical judgment, the dentist will make an acrylic guide (called a stent) prior to surgery which guides optimal positioning of the<unk> . Increasingly, dentists opt to get a CT scan of the jaws and any existing dentures, then plan the surgery on CAD/CAM software. The stent can then be made using stereolithography following computerized planning of a case from the CT scan. The use of CT scanning in complex cases also helps the surgeon identify and avoid vital structures such as the inferior alveolar nerve and the sinus. Bisphosphonate drugs The use of bone building drugs, like bisphosphonates and anti-RANKL drugs require special consideration with<unk> s, because they have been associated with a disorder called Medication-associated osteonecrosis of the jaw (MRONJ). The drugs change bone turnover, which is thought to put people at risk for death of bone when having minor oral surgery. At routine doses (for example, those used to treat routine osteoporosis) the effects of the drugs linger for months or years but the risk appears to be very low. Because of this duality, uncertainty exists in the<unk>  community about how to best manage the risk of BRONJ when placing<unk> s. A 2009 position paper by the American Association of Oral and Maxillofacial Surgeons, discussed that the risk of BRONJ from low dose oral therapy (or slow release injectable) as between 0.01 and 0.06 percent for any procedure done on the jaws<unk> , extraction, etc.). The risk is higher with intravenous therapy, procedures on the lower jaw, people with other medical issues, those on steroids, those on more potent bisphosphonates and people who have taken the drug for more than three years. The position paper recommends against placing<unk> s in people who are taking high dose or high frequency intravenous therapy for cancer care. Otherwise,<unk> s can generally be placed and the use of bisphosphonates does not appear to affect<unk>  survival. Main surgical procedures Placing the<unk>  Most<unk>  systems have five basic steps for placement of each<unk> : # Soft tissue reflection: An incision is made over the crest of bone, splitting the thicker attached gingiva roughly in half so that the final<unk>  will have a thick band of tissue around it. The edges of tissue, each referred to as a flap are pushed back to expose the bone. Flapless surgery is an alternate technique, where a small punch of tissue (the diameter of the<unk>  is removed for<unk>  placement rather than raising flaps. # Drilling at high speed: After reflecting the soft tissue, and using a surgical guide or stent as necessary, pilot holes are placed with precision drills at highly regulated speed to prevent burning or pressure necrosis of the bone. # Drilling at low speed: The pilot hole is expanded by using progressively wider drills (typically between three and seven successive drilling steps, depending on<unk>  width and length). Care is taken not to damage the osteoblast or bone cells by overheating. A cooling saline or water spray keeps the temperature low. # Placement of the<unk> : The<unk>  screw is placed and can be self-tapping, otherwise the prepared site is tapped with an<unk>  analog. It is then screwed into place with a torque controlled wrench at a precise torque so as not to overload the surrounding bone (overloaded bone can die, a condition called osteonecrosis, which may lead to failure of the<unk>  to fully integrate or bond with the jawbone). # Tissue adaptation: The gingiva is adapted around the entire<unk>  to provide a thick band of healthy tissue around the healing abutment. In contrast, an<unk>  can be "buried", where the top of the<unk>  is sealed with a cover screw and the tissue is closed to completely cover it. A second procedure would then be required to uncover the<unk>  at a later date. Timing of<unk> s after extraction of teeth There are different approaches to placement<unk> s after tooth extraction. The approaches are: #Immediate post-extraction<unk>  placement. #Delayed immediate post-extraction<unk>  placement (two weeks to three months after extraction). #Late<unk> ation (three months or more after tooth extraction). An increasingly common strategy to preserve bone and reduce treatment times includes the placement of a<unk>  into a recent extraction site. On the one hand, it shortens treatment time and can improve aesthetics because the soft tissue envelope is preserved. On the other hand,<unk> s may have a slightly higher rate of initial failure. Conclusions on this topic are difficult to draw, however, because few studies have compared immediate and delayed<unk> s in a scientifically rigorous manner. One versus two-stage surgery After an<unk>  is placed, the internal components are covered with either a healing abutment, or a cover screw. A healing abutment passes through the mucosa, and the surrounding mucosa is adapted around it. A cover screw is flush with the surface of the<unk> , and is designed to be completely covered by mucosa. After an integration period, a second surgery is required to reflect the mucosa and place a healing abutment. In the early stages of<unk>  development (1970−1990),<unk>  systems used a two-stage approach, believing that it improved the odds of initial<unk>  survival. Subsequent research suggests that no difference in<unk>  survival existed between one-stage and two-stage surgeries, and the choice of whether or not to "bury" the<unk>  in the first stage of surgery became a concern of soft tissue (gingiva) management When tissue is deficient or mutilated by the loss of teeth,<unk> s are placed and allowed to osseointegrate, then the gingiva is surgically moved around the healing abutments. The down-side of a two-stage technique is the need for additional surgery and compromise of circulation to the tissue due to repeated surgeries. The choice of one or two-stages, now centers around how best to reconstruct the soft tissues around lost teeth. Additional surgical procedures For an<unk>  to osseointegrate, it needs to be surrounded by a healthy quantity of bone. In order for it to survive long-term, it needs to have a thick healthy soft tissue (gingiva) envelope around it. It is common for either the bone or soft tissue to be so deficient that the surgeon needs to reconstruct it either before or during<unk>  placement. Hard tissue (bone) reconstruction Bone grafting is necessary when there is a lack of bone. Also, it helps to stabilize the<unk>  by increasing survival of the<unk>  and decreasing marginal bone level loss. While there are always new<unk>  types, such as short<unk> s, and techniques to allow compromise, a general treatment goal is to have a minimum of 10 mm in bone height, and 6 mm in width. Alternatively, bone defects are graded from A to D
Dental implant
Root analogue dental implant
Dental vibration appliance
Brain implant
Facial implant
Surgery for temporomandibular joint dysfunction
Shoulder surgery
Facial prosthetic