Clinical outcome of overdenture treatment on two nonsubmerged and nonsplinted Astra Tech Microthread™ implants

The use of two implants for mandibular overdenture stabilization improves the patients' comfort and well-being. This treatment could be more cost-effective if surgery and prosthetic treatment could be performed by one clinician in the normal setting of a dental clinic. The aim of this retrospective clinical study was to describe implant success, restorative outcome, and the patients' opinion of mandibular overdenture treatment on two early-loaded, nonsplinted Astra Tech TiOblast Microthread (TM) (Astra Tech Dental, Molndal, Sweden) implants. Thirty-seven consecutive patients treated with implant-supported mandibular overdentures were invited for a clinical examination. Implant survival, marginal bone level, quality of implant and prosthetic treatment, and the patients' opinion by means of questionnaires were scored. Thirty-four patients attended the examination. Two implants were lost in one patient and the failure rate for the total group of patients was 3%. As 8 of the 33 remaining patients were still in the provisional loading stage, they were not included in the final clinical and radiographic examination. Based on 25 patients and 50 implants with a mean follow-up of 18.8 months (range 4-33), implant positioning and occlusion/articulation scored perfect in 74 to 80% of the cases. Retention of the dentures was rated perfect in 80%, but 20% needed minor activation of the attachments, 20% showed signs of abrasion, and 20% had already been repaired. The average marginal bone level was 0.8 mm below the reference point. The mean pocket depth was 2.1 mm, and 54% of the peri-implant tissues were free of bleeding. The patients were appreciative of the work carried out by their dentist and they indicated a significant improvement in their well-being and quality of life. It can be concluded that the Astra Tech implant system was successfully used by the general dentist both surgically and prosthetically with minimal implant failures and prosthetic complications and that this led to high levels of patient appreciation and overall satisfaction