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.

A double-blind study was performed in two groups of young, healthy women without signs or symptoms of mandibular dysfunction. Each group contained 12 individuals. In one of the groups, balancing-side interferences were applied bilaterally, whereas the application was simulated in the other group. The participants were re-examined after 2 weeks. Ten individuals in the experimental group reported one or more subjective symptoms during the 2 weeks, whereas seven exhibited clinical signs of dysfunction. The commonest symptom was headache, and the commonest clinical sign was muscles tender to palpation. In the control group, three individuals reported subjective symptoms, and three had clinical signs of dysfunction. One week after elimination of the interferences, all signs and symptoms had disappeared in all individuals but two. In these two subjects it took 6 weeks before pre-experimental conditions were restored. It is concluded that there is no simple relationship between interferences and signs and symptoms of dysfunction. How the individual reacts to local factors depends on his or her psychic condition. In some individuals addition of balancing-side interferences is sufficient to create dysfunction. The findings thus underline the importance of local factors in the etiology of mandibular dysfunction but show that a relationship is not obligatory.

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