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In vivo temperature measurements were performed at drilling in the femoral cortex of the rabbit, dog and man. In the clinical study the bone temperature was measured at fixation of a Richards plate to stabilize a pertrochanteric fracture. With a drill speed of around 20 000 rpm and saline cooling, temperatures of 40 degrees C in rabbits, 56 degrees C in dogs and 89 degrees C in patients were recorded at a distance of 0.5 mm from the periphery of the drill hole. The difference in temperature between the animal and clinical studies was mainly attributed to the difference in cortical thickness between the species. When drilling straight through the canine femur from the lateral to the medial side, a 9 degrees C higher temperature was measured in the remote, medial cortex compared to that recorded in the lateral cortex. This difference arose because it is difficult for the cooling agent to reach the medial cortex. The results of the present study indicate that temperatures measured in animal experiments are not applicable to the clinical situation where very high temperatures may arise on drilling in cortical bone, even if saline cooling is used.

Fourteen Swedish teams outside the University of Gothenburg, each with minimally three years' experience in the Nobelpharma osseointegrated implant participated in a retrospective multiclinic study. The total number of consecutively inserted implants at the 14 clinics was 8139. The outcome of every implant was reported and all implant failures, irrespective of when they occurred, were published. The success criteria included absence of implant mobility, absence of radiolucent zones on x-rays, and an annual bone loss after the first year of less than 0.2 mm. In the mandible 334 implants were followed for five to eight years, with only three failures, for a success rate of 99.1%. In the maxilla 106 implants were followed for five to seven years, with a success rate of 84.9%. In irradiated and grafted mandibles, 56 implants were inserted and none was lost during a follow-up of up to five years. In the irradiated maxilla there were 16 implants inserted with three reported failures and in the grafted upper jaw 71 implants were inserted with 12 failures. The proportions of mandibular and maxillary sleeping implants were 0.8 and 0.3%, of patient drop-out implants 0.3 and 0.6%, and of patient death implants 0.9 and 1.2%, respectively. It was concluded that the osseointegrated implant, if inserted according to the guidelines of Brånemark, results in a very high degree of clinical success, thereby meeting any published oral implant success criteria.

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