Determinative Diagnostic Criteria

Tooth Maintenance or Dental Implant?

This question can only be answered on a case-by-case basis. In healthy patients, implant success rates of 99% after 15 years have been reported (Lindquist et al. 1996). In patients suffering systemic disease, as well as those manifesting aggressive periodontitis, the success rate is much lower. Thus the predictability of success is also reduced, and there can be no “guaranteed” prognosis. Local risk factors (oral hygiene, compliance etc.), and above all general systemic risks (smoking, diabetes, osteoporosis, hematologic disorders) must be definitively characterized and diagnosed before making the decision about whether a tooth should be maintained “at all costs” (van Steenberghe 2003).

These decisions demand careful examination of the general medical history and all specific clinical data. It remains within the competency of the dentist to interpret the numerous aspects of each case in order to determine the appropriate and long-term functional treatment plan.

Maintenance of natural teeth

Not only in dental implantology, but also in regenerative periodontal therapy, enormous advances have been made. If periodontal therapy—alone—can lead to success, implant therapy is not indicated; this is especially true for teeth in the “risk areas” such as the maxillary posterior segment (maxillary sinus) or mandibular molars (mandibular canal/mental foramen).

If a prospective abutment tooth requires initial endodontic treatment, post build-up etc., it is important to consider and compare the length of treatment, the costs and the prognosis in comparison to dental implant therapy. Especially in such cases, the well-informed patient must participate in the decision.

Replacement via dental implants

In many partially edentulous patients, such decisions are not even necessary; the decision is simply between fixed bridgework including dental implants, or a removable partial denture.

Teeth that exhibit severe periodontal compromise and which are in danger of progressive disease are better extracted early on in order to preclude extensive loss of the osseous fundament that will be necessary for subsequent dental implant therapy.

Diagnosis before Dental Implant Therapy

Before making a definitive decision in favor of dental implants, the identical clinical examinations and findings must be collated as for all periodontitis patients (p. 165). Additional radiographic examinations (CT scans) provide information in complex or risk-rich cases concerning shape, structure, and thickness of the alveolar ridge, as well as concerning special structures such as the maxillary sinus, mandibular canal, persistent areas of ostitis, thickness of the compact bone layers and therefore indirectly concerning the bone quality (Lekholm & Zarb 1985).

Simultaneously, the prosthetically relevant parameters as they relate to the set-up plan and positions of the fixtures can be depicted in the radiographs (templates with marker points). This permits the observation of the implant sites before the surgical procedure.

In cases in which the alveolar process is significantly deformed, the implants may have to be positioned in unconventional areas of the alveolar ridge. Today, implants are not necessarily placed where bone remains, rather in locations where the prosthodontist needs them for her/his crown and/or bridge constructions (“backward planning”); additional surgical procedures may be necessary.