Analysis of the dimensional changes in bone grafts after maxillary sinus augmentation procedure.

Abstract

Purpose During sinus augmentation, various bone graft substitutes and/or their combination are used. They have varying rates of remodeling and cause different volume changes in the grafted material. This study aimed to investigate the potential time-dependent dimensional changes in graft materials of xenografts and allografts placed using the layering technique, (xenograft placed close to the sinus membrane, while the bone allograft fills the remaining sinus cavity) following a maxillary sinus elevation procedure. Methods CBCT records were available for 16 patients referred for contralateral sinus augmentation and implant placement. In these cases, additional CBCT performed prior to the procedure revealed graft dimensional changes. Linear measurements of the augmented bone grafts were performed at three identical locations at two-time points. Linear regression, one-way ANOVA and Pearson's and Spearman’s correlations were used for statistical analysis. P values ≤ 0.05 were considered statistically significant. Results There was no statistically significant variation in the rate of dimensional change across the different evaluated locations in the augmented graft (p = 0.816). At the peak of augmentation, each additional month corresponded to a decrease of 1.556 mm² (95% CI, -2.723 to -0.388) in the bone dimensions. The changes of the amount of bone filler material above the implant was related to gender (t= -2.167, p = 0.049) and implant diameter (t = 3.251, p = 0.012). Conclusions The combination of xenografts and allografts in maxillary sinus augmentation, applying layer technique, underwent dimensional changes over time and amounted to a 1.5mm² reduction per month. More residual bone was observed among female patients and wider implant diameters.