Treatment Planning Posterior Sextants

As described in Chap. 1 , “Rationale for Dental Implants”, it is not mandatory to have a full complement of teeth when posterior teeth are missing; however, in situations where bite forces overcome the periodontal attachment support of the remaining teeth, some patients may suffer a “loss of posterior support”—the placement of implants in this situation is most beneficial. Loss of posterior support is also known as “posterior bite collapse”; this is primarily due to occlusal forces that overcome the support of the remaining periodontal attachment. This refers to either loss of posterior teeth that cause overloading of the remaining dentition due to heavy bite forces or to remaining dentitions that have a reduced periodontal support due to periodontitis leading to attachment loss. In either situation where bite forces overcome the periodontal support available, symptoms that manifest are increasing mobility of remaining teeth, migration of teeth, fremitus, flaring of the anterior teeth and a reduction of vertical dimension. When patients present with all or some of the symptoms described above, dental implants would be best indicated to restore posterior support and oral function. With missing posterior teeth, other avenues of restoration include the following: tooth-supported cantilever fixed partial dentures that have a well-documented history of failure due to decay of abutment teeth; fracture of abutment teeth due to weakened teeth due to removal of tooth structure; and often when endodontic therapy is required, the abutment teeth are weakened and prone to fracture. Distal extension removable partial dentures do not provide support in posterior sextants as the mucosa cannot provide the support that teeth or implants do. In addition, the forces applied to the remaining anterior teeth and the areas of stasis that cause plaque accumulation will facilitate tooth decay or periodontitis leading to attachment loss. Dental implants are the most suitable replacement of missing teeth compared to the other modalities discussed above; in addition, the implant-supported restorations provide additional support and distribute the forces that are generated with occlusion. When patients do not suffer from loss of posterior support, implants in the posterior sextants can reduce wear of the remaining dentition. In addition, dental implants have demonstrated a very high survival rate over the long term.