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Health See other Health Articles Title: Dental Implant Placement Dental implant placement is no longer performed only by oral surgeons and periodontists; general dentists are also increasingly providing difficult surgical implant services. Dental implants may be used to replace single teeth, replace multiple teeth, or provide abutments for complete dentures or partials. This topic focuses on the placement of single-tooth dental implants. In the 1960s, Branemark introduced the concept of osseointegration as it applies to dental implants.[1] Since that time, a multitude of different dental implant types have been introduced into the market and are being used in daily dental practice. Osseointegration, as applied to dental implants, refers to the postinsertion result in which medullary bone has grown up to or into the material of the implant without interposition of a connective tissue layer between the bone and the alloplastic implant material. Osseointegration can be contrasted with fibroosseous integration, in which there is a soft-tissue interface that is viewed as the equivalent of the periodontal ligament that surrounds the tooth. Both mechanisms can facilitate retention of an implant, but osseointegration is considered more suitable for long-term implant success. Indications Implants can be used to replace single teeth, multiple teeth, or used to provide abutments for complete dentures or partials. Contraindications In addition to evaluation of the patient’s underlying health, it is important to assess for preexisting periodontal disease as peri-implantitis, a periodontal condition similar to periodontitis that is associated with gingival tissue inflammation, pocket formation, and ultimately loss of bone that can lead to implant failure. Implants that are placed adjacent to teeth with periapical lesions may also be at greater risk of failure.[2] Another patient factor that has been associated with peri-implant microbiota and potential disease and implant failure is smoking.[3] The presence of dental caries on adjacent teeth is not a contraindication for implant placement, but lesions should be eliminated and teeth restored prior to proceeding with surgical procedures. Outcomes From a biomechanical standpoint, several factors appear to be important in determining the success of implant placement as they relate to technique: stiffness of the tissue-implant interface, the quality of the supporting tissues, and implant diameter, particularly as it applies to short implants. Bone density around submerged implants that failed was found to be significantly less than in those implants that survived. Additionally, it was found that there was a tendency towards higher failure rates of machined (smooth) surface implants versus those with rough surfaces and in those placed where there was poor bone quality.[4] There has been a significant lack of well-controlled prospective longitudinal studies comparing the success rates of different implant systems. Many published studies are retrospective in nature and thus must be interpreted with caution.[5] Population size is also problematic in many studies. With respect to survival rate, the probability of failure for industry-associated clinical trials was significantly lower than that that reported in nonindustry research, as reported in a systematic review of 38 published clinical trials.[6] Based on the analysis of these studies, funding sources may have a significant effect on the reporting of implant failure. Thus, all survival data must be interpreted with caution. In a retrospective study evaluating 206 immediate implants using a flapless technique and immediate loading, the cumulative survival rate at a mean of 23 months was 98.77%.[7] Complications Tissue Loss Tissue loss is of particular concern in the anterior maxillary and mandibular region. The causes of tissue loss include smoking, flap design, and poor oral hygiene. Postplacement plaque control is also important. It is important to have a good peri-implant soft tissue seal and the preservation of a keratinized gingival zone to promote plaque control. Patients receiving implants should be instructed on the importance of plaque control and monitoring for implant survival. Crestal Bone Preservation The loss of crestal bone around an implant results in an environment conducive to anaerobic colonization, which can lead to peri-implantitis and implant failure. Early bone loss has been associated with several factors, including the effect of tissue manipulation during surgery on blood flow, osteotomy preparation, bacterial colonization, lack of biologic seal around the implant, plaque accumulation at the implant-transmucosal abutment interface,[8] implant design features, flap elevation,[9] and stress.[10] It has been reported that crestal bone loss is a fairly normal consequence of implant placement when it involves two stages. It does not typically occur when the implant remains completely submerged but can occur during the exposure surgery and placement of the abutment. There is evidence that platform shifting at the time of abutment placement can act to prevent crestal bone resorption.[11] When implants placed with conventional drilling techniques were compared with those placed via osteotome technique for crestal bone loss, it was found that at month 3 the osteotome group experienced significantly more crestal bone loss. However, by months 6 and 12, there were comparable bone levels.[12] Treatment Failure Implants can fail for a number of reasons, including the following: Lack of osseointegration Fracture of bone during the osteotomy Graft failure Prosthetic design Postimplant soft tissue defects Improper selection of implant type Patient force factors Miscalculation of bone density or tissue thickness Patient health and lifestyle factors Comorbid periodontal disease Poor drilling technique However, research suggests that cumulative survival rates for dental implants are excellent, even if training is of a limited nature. Success rates for dental implants were reported to be greater than 90% for both maxillary and mandibular implants, with mandibular implants having a greater survival rate than maxillary implants.[13] In patients with placed implants, there is evidence that the survival of the initial implant correlates with the survival of subsequent implants and vice versa. Next Section: Periprocedural Care Poster Comment: maxillary - relating to a jaw or jawbone, especially the upper one. The Mandible (Lower Jaw) - Gray's Anatomy of the Human Body ... The mandible, the largest and strongest bone of the face, serves for the reception of the lower teeth Post Comment Private Reply Ignore Thread
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