In this paper, both the surgical procedure and the clinical results of a novel distraction device to augment a severely resorbed anterior edentulous mandible are described. The distraction device is non-voluminous, and consists of two distraction screws and one guide screw. Two months after the last day of distraction, both distraction screws are replaced by endosseous implants and the guide screw is removed. Three months after implantation, the prosthetic treatment can be started. So far three patients have been treated. In all patients, the severely resorbed mandible (mandibular height in the canine region: 5, 6 and 7 mm, respectively) could be sufficiently enlarged to enable reliable insertion of endosseous implants with a length of at least 12 mm. No complications occurred. Biopsies taken from the distraction site revealed formation of lamellar bone parallel to the distraction vector. From this preliminary study it is concluded that the Groningen vertical distraction device has the potential for reliable augmentation of the anterior segment of a severely resorbed edentulous mandible to enable insertion of endosseous implants with adequate length and primary stability.

The aim of this study was to evaluate the feasibility of using a two-stage implant system in a single-stage procedure and to study the impact of the microgap at crestal level and to monitor the microflora in the peri-implant area. Forty edentulous patients (Cawood & Howell class V-VI) participated in this study. After randomisation, 20 patients received two IMZ implants inserted in a single-stage procedure and 20 patients received two ITI implants. After 3 months, overdentures were fabricated, supported by a bar and clip attachment. A standardised clinical and radiographic evaluation was performed immediately after denture insertion and 6 and 12 months later. Twelve months after loading, peri-implant samples were collected with sterile paper points and analysed for the presence of putative periodontal pathogens using culture techniques. One IMZ implant was lost due to insufficient osseointegration. With regard to the clinical parameters at the 12 months evaluation, significant differences for plaque score and probing pocket depth (IMZ: mean 3.3 mm, ITI: mean 2.9 mm) were found between the two groups. The mean bone loss in the first year of functioning was 0.6 mm for both groups. Prevotella intermedia was detected more often in the ITI group (12 implants) than in the IMZ group (three implants). Porphyromonas gingivalis was found in three patients. In one of these patients an implant showed bone loss of 1.6 mm between T0 and T12. Some associations were found between clinical parameters and the target microorganisms in the ITI group. These associations were not present in the IMZ group. The short-term results indicate that two-stage implants inserted in a single-stage procedure may be as predictable as one-stage implants. The microgap at crestal level in nonsubmerged IMZ implants seems to have no adverse influence on the peri-implant microbiological colonisation and of crestal bone loss in the first year of functioning. The peri-implant sulcus can and does harbour potential periodontal pathogens without signs of peri-implantitis during the evaluation period of 1 year.

Objective: The aim of this study was to evaluate the feasibility of using a twopart implant system in a one-stage procedure and to monitor the microflora in the peri-implant area in relation to clinical and radiographic outcome. A standardised clinical and radiographic evaluation was performed after denture insertion as well as 6 and 12 months thereafter. Twelve months after loading, peri-implant samples were collected and analysed for the presence of putative periodontal pathogens using culture technique. Results: No striking differences were found between the two groups with regard to the clinical parameters during the evaluation period. The mean bone loss in the first year of functioning was 0.6 mm in both groups. With regard to the gingiva score, plaque score, bleeding score or bone loss between T0 and T12, no associations were found with the presence of the cultured microorganisms. An association was present between pockets Ն4 mm and the presence of Peptostreptococcus micros in the two-stage group. Conclusions: The short-term results indicate that two-part implants inserted inKey words: dental implants; edentulous; a one-stage procedure may be as predictable as inserted in the common two-stage overdenture; one-stage; microorganisms procedure. The peri-implant sulcus can and does harbour potential periodontal pathogens without significant signs of tissue breakdown.

The results from this study suggest that an implant-retained MRA in the mandible is a viable treatment modality in edentulous OSAHS patients. Because the therapeutic effectiveness of this treatment may be compromised by excessive pressure of the MRA on the labial mucosa in the maxilla, we suggest that an implant-retained MRA in the maxilla be offered as a secondary treatment in selected patients.

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