Glycosaminoglycans in peri-implant sulcus fluid from implants placed in sinus-inlay bone grafts

Glycosaminoglycans (GAG) present in peri-implant sulcus fluid (PISF) were used as an indicator of the metabolic activity in the supporting tissues of implants placed in maxillary bone or maxillary bone and bone grafts together. The study included 16 patients who received implants (Brånemark system(R)) and sinus-inlay bone grafts. In 12 of these patients, the implants were placed in either maxillary bone alone or maxillary bone and sinus-inlay bone grafts in combination. Altogether the patients received a total of 102 implants, of which 73 implants were placed in bone grafts and 29 implants in maxillary bone alone. Samples of PISF were tested at 2-8 days and at 6 months after abutment connection. Levels of the GAG's chondroitin-4-sulphate (C4S) and hyaluronan (HA) were assessed using cellulose acetate electrophoresis and densitometric scanning of Alcian blue-stained strips against known GAG standards. The C4S was used as a bone metabolic marker, and HA was used to reflect the progress of soft tissue healing. Comparing grafted and non-grafted regions, there was no significant difference in either C4S levels or HA levels during the first 8 days or at the 6 months period. The levels of HA from the first week collection did not differ significantly from the HA level after 6 months in either type of bone. However, the level of C4S was significantly lower after 6 months than during the first week, in both maxillary and grafted bone but consistent with a normal metabolic turnover. C4S can therefore be used as an indicator of the progressive healing of bone adjacent to implants.