The implant site 79

It is not necessary to splint a triplant as soon as it is inserted, because its splayed pins provide immediate mechanical retention. Splinting the triplant to place it in functional occlusion is also not essential, since the beneficial effects of normal functional occlusion on bone plays little role in the success of this type of implant. However, as cells die back from the implant site, the initial mechanical stability is lost. Now loose, the implant is prone to tipping by forces exerted against it. This traumatizes the bone, causing further resorption and enlargement of the pin sites. Splinting helps immobilize the implant and reduce trauma.

Periodontal disease and an implant

Any pathologic condition that can involve a natural tooth can also affect an implant. If the false periodontal ligament becomes disorganized and non-functional because of occlusal trauma, the epithelial tissue will move clown along the implant, creating conditions similar to those in periodontosis. If a pocket forms and becomes filled with bacterial or chemical debris, inflammation will spread and cause the degeneration of adjacent tissues.

The gingiva around an implant post may also be irritated by poor oral hygiene. The resulting inflammation will spread in the true picture of periodontitis. Since more teeth are lost because of perioclontal disease than any other cause, the dentist should emphasize the role of good oral hygiene during patient instruction on the care of an implant-supported prosthesis.

Evaluating local and systemic conditions that could lead to periodontal disease should be a routine part of the dentist's follow-up program.

CLINICAL CONSIDERATIONS

A dental prosthesis should be planned not only to provide additional chewing surfaces and to improve the esthetic appearance of the mouth, but also to help preserve any remaining teeth. An endosseous implant-supported fixed denture offers so many advantages in achieving this goal that the merits of such support can no longer be denied by any open-minded practitioner.

Teeth that have been loosened by periodontal disease can usually be saved if included in an implant-supported restoration. The additional stability gained from advantageously placed artificial sup-ports not only prevents further loosening of these teeth but also prevents the traumatization of other teeth and their subsequent involvement in periodontal disease.

Because the entire dentition tends to become involved if compatible occlusal patterns are not re-established after tooth loss, the importance of providing stable artificial abutments for a fixed partial denture cannot be underestimated. Certain problems of perioclontal-prosthodontic interrelationships may now be more successfully resolved by the use of endosseous implants than by conventional methods.

Natural tooth abutments

Like other types of fixed dentures, an implant-borne prosthesis must be supported by natural tooth abutments. These serve primarily to eliminate lateral movements or torsion on the implant. However, as natural tooth abutments on one end of a splint inhibit torsion on the implant-supported end, so does an implant reduce the possibility of torsion action on the natural tooth abutments. This is a particularly advantageous feature when the natural teeth have weakened periodontal tissues.

When a conventional fixed partial denture is used in a posterior edentulous situation, it usually includes two or more natural tooth abutments. These have frequently been weakened by drifting toward the edentulous area. Although including several teeth as abutments and carrying the splint around the arch to avoid straight line segments may reduce torsion on the teeth, an implant in the edentulous area provides the most effective method to date of minimizing such movement. By anchoring the splint in the area where such activity may be initiated, an obvious advantage is provided (Fig. 3-40).

Anterior splints, even when including the cuspid teeth, tend to be tipped by labiolingual actions. One or more implants used in the posterior region prevent this.

Fig. 3-40. An advantageously placed endosseous implant not only anchors the splint in the area but also helps protect natural tooth abutments from torsion.