Immediate/Early function of Neoss implants placed in maxillas and posterior mandibles: an 18-month prospective case series study.

BACKGROUND

An increasing number of studies show that immediate/early function of dental implants can be as successful as two-stage procedures. However, the results may not be universal for all implant types and it is important that new implants are tested for this treatment modality.

PURPOSE

The aim was to evaluate an immediate/early function protocol in the maxilla and in the posterior mandible using Neoss implants (Neoss Ltd., Harrogate, UK).

MATERIALS AND METHODS

A total of 21 patients were provided with 69 Neoss implants (4 mm in diameter and 9-15 mm in length) and a provisional bridge within 7 days (mean 4.6 days). Sixteen implants were placed in immediate extraction sites where seven were treated with autologous bone grafts (n = 6) or bone grafts + resorbable membrane (n = 1). A final fixed prosthesis was made 3 to 6 months later. The patients were followed-up with clinical examinations for 18 months. In addition, the implants were monitored with resonance frequency analysis (RFA) measurements at surgery and after 1, 2, and 6 months. Intraoral radiographs were taken after surgery and after 1, 6, and 18 months.

RESULTS

One implant in an extraction site in the maxilla failed after 1 month, giving a survival rate of 98.5% after 18 months. The mean marginal bone loss was 0.7 mm (SD 0.7) after 18 months. RFA showed a mean implant stability quotient (ISQ) value of 68.1 (SD 8.8) at surgery, which increased to 73.7 (SD 5.7) after 6 months. The primary stability for maxillary and mandibular implants was similar, although mandibular implants showed slightly higher values with time. Implants in extraction sockets showed a lower initial stability than in healed sites, ISQ 65.8 (SD 7.5), which increased to ISQ 67.5 (SD 6.9) after 6 months. The failed implant showed an ISQ of 74 at placement, which decreased to 42 1 month after surgery.

CONCLUSION

Within the limitations of the present study, it is concluded that immediate/early function with Neoss implants is a reliable method with an implant survival rate comparable to that of the traditional two-stage protocol.