Immediate functional loading of Brånemark System implants with enhanced initial stability: a prospective 1- to 2-year clinical and radiographic study.

BACKGROUND: The interest in the benefits of immediate loading of titanium implants has recently involved fixed prostheses for partially edentulous areas. The advantages of this approach well justify the need for extending the procedure to all regions of the mouth. Current available clinical literature on this subject is incomplete.

PURPOSE: The purpose of this study is to investigate the clinical outcome of the immediate loading of Brånemark System implants (Nobel Biocare AB, Gothenburg, Sweden) inserted with enhanced initial stability principally in posterior sites (78%).

MATERIALS AND METHODS: The present study was conducted in 26 consecutively treated patients. A total of 50 Brånemark System machined surface implants were placed supporting 30 fixed temporary partial dentures in light occlusion. All implants were followed up for a minimum of 1 year of function. Minimum requirements for immediate loading were proposed. Bone quality and quantity were classified according to Lekholm and Zarb's criteria. Stability of the marginal bone level, both mesial and distal, was measured on the basis of radiographic analysis. Implant survival rate was calculated according to Kaplan-Meier analysis. The peak insertion torque employed during fixture placement was between 40 and 72 Ncm, except in the case of one implant that was lost.

RESULTS: Overall survival rate was 98%. An unpaired t-test revealed bone remodeling conforming to biologic width establishment (p <.005).

CONCLUSIONS: Within the limit of this study, immediate loading appears to be a viable procedure in posterior sites and for a growing number of clinical indications. Enhanced implant stability and light occlusion seem to be security factors. In spite of unfavorable conditions such as the presence of quality 4 bone and a lack of splinting, all implants with enhanced primary stability survived.