Monophasic ß-TCP vs. biphasic HA/ß-TCP in two-stage sinus floor augmentation procedures - a prospective randomized clinical trial

ObjectivesTo compare a monophasic (100% ss-TCP) and a biphasic (60% HA and 40% ss-TCP) bone substitute material (BSM) regarding biocompatibility, osteoconductivity and implant stability using histological, radiological and resonance frequency analysis. Material and MethodsSixty-seven sinus floor elevations were performed in 60 patients. One patient group (monophasic bone substitute [MBS], 30 patients, 32 sinuses) was augmented by the use of the monophasic material (Bioresorb((R)), Sybron Implant Solutions, Bremen, Germany), while the second group (biphasic bone substitute (BBS), 30 patients, 35 sinuses) received a biphasic material (Maxresorb((R)), Botiss Biomaterials, Berlin, Germany). Cone beam CT images were taken immediately after augmentation and prior to implant placement after 6months. Trephines were harvested, while the implant bed was prepared. Resonance frequency analysis was performed immediately after implant placement and 6months later. Descriptive analysis was performed on all augmented sinus (n=67). For statistical comparison of the groups, one sinus of each bilaterally treated patient was randomly excluded, resulting in 30 sinuses grafted with MBS and 30 sinuses grafted with BBS (n=60). ResultsHistomorphometrical analysis of all sinuses displayed comparable results for both groups regarding new bone matrix (MBS 36.1619.37%, BBS 38.42 +/- 12.61%), residual BSM (MBS 30.26 +/- 11.7%, BBS 32.66 +/- 12.57%) and non-mineralized tissue (MBS 34.29 +/- 18.32%, BBS 28.92 +/- 15.04) %) (P>0.05, respectively). Radiological volume of BBS was significantly more stable (volume loss of 22.2% for MBS, 6.66% for BBS; P<0.001), and homogeneity of the graft after 6months was higher for BBS than that for MBS (P<0.05). Resonance frequency analysis endorsed a higher implant stability quotient for BBS after 6months than that for MBS (MBS 78.31 +/- 5.81, BBS 80.42 +/- 6.31; P<0.05, Mann-Whitney U-test, respectively). ConclusionBoth monophasic and biphasic materials show good biocompatibility and osteoconductivity with satisfactory support on implant stability. BBS remains more stable in terms of volume maintenance and radiological graft homogeneity after a healing period of 6months.