Preventive implantations.

Preventive implantology is concerned with the preservation of the alveolar ridge of the (edentulous) jaw. Maintaining the volume of the alveolar ridge is a major problem in the prevention of oral disease. Loss of teeth and tooth roots leads to resorption of residual ridges. This being so, it is a logical approach to substitute artificial analogues for lost tooth roots. Hydroxyapatite implants have been studied as submerged tooth root substitutes and shown to maintain the bulk of the alveolar ridge. A drawback of the implants is that the ridge maintenance depends solely on the physical presence of the hydroxyapatite implants. No physiological influence on bone preservation can be attributed to the implants. However, long term research indicates that 75 per cent of the implants survive under full lower dentures and 100 per cent of the implants under fixed partial dentures.