Clinical and instrumental evaluation of implant stability after free fibula flaps for jaw reconstruction

Osseointegration is a direct union between bone and an allograft with no soft tissue interposition. It represents the morphological basis of secondary stability. Introduction of Resonance Frequency Analysis (RFA) as a commercially available technique has made it possible to measure implant stability as an Implant Stability Quotient (ISQ) unit at any time during the course of implant treatment and loading. The study aims to clinically and objectively analyze the stability of implants loaded upon revascularized free fibula flaps on patients who underwent maxilla or mandible reconstruction following trauma, oncological resection or class V–VI Cawood's atrophy treatment. Of the 105 patients that underwent jaw bone reconstruction with free fibula flaps in our division between 1993 and 2003, 37 were eligible for implant-supported dental rehabilitation. Of these, the last 12 were selected and included in the study. Primary and secondary implant stability assessments involved a clinical evaluation, radiograms and RFA measurements using the Osstell (Integration Diagnostics, Savedalen, Sweden) at the time of implant insertion, at 6 months and at 1 year of functional loading. 76 implants were loaded in 12 patients. All of them were clinically stable at each evaluation. Radiograms showed modest bone resorption after 1 year of functional load in 16 implants (21%). Implant stability levels ranged from 48 to 74 ISQ (mean 59.9±7.8 ISQ) at 6 months. At 1 year, the mean ISQ level was higher (62.6±7.2) but still coherent according to the radiographic evidence. Implant-supported dental rehabilitation of the reconstructed jawbone is not always possible. Free fibula flap represents a good substrate for implant osseointegration being a bicortical bone capable of structural remodelling after masticatory load enhancement. When possible, instrumental evaluation of implant stability with RFA and supported by radiograms represent the best objective way to assess osseointegration as a clinical evidence alone is unable to offer a definitive assessment.