Analysis of the influence of residual alveolar bone height on sinus augmentation outcomes

Introduction Maxillary sinus augmentation is a predictable implant site development technique for posterior atrophic maxillary ridges. However, graft consolidation requires adequate angiogenesis and migration of osteogenic cells from native bone. Therefore, the amount of residual bone height ( RBH ) may play a role in the rate of graft maturation. The purpose of this study was to analyze the influence of RBH in the histomorphometric outcomes of maxillary sinus augmentation procedures. Material and methods Patients in need of sinus augmentation were recruited for the study. Customized radiographic guides were fabricated and a cone‐beam computerized tomography scan was obtained at baseline. Two examiners measured RBH on the scans at the locations marked by the radiographic guide. Sinus grafting was performed by a lateral window approach using a particulated mineralized allograft. Patients were followed up for 6 months. At the time of implant placement, bone core biopsies were harvested using the radiographic guide, which was converted into a surgical guide. Samples were histomorphometrically analyzed. Proportion of vital bone (% VB ), remaining allograft particles (% RA ), and non‐mineralized tissue (% NMT ) were quantified. Categorical analysis of correlation of RBH (<4 or ≥4 mm) with% VB and% RA was performed using a statistical model. Results Twenty‐one patients underwent sinus augmentation for a total of 21 sinuses. One patient developed an infection after grafting and was excluded. Histomorphometric analysis revealed that mean% VB was 20.47 ± 18.25, mean % RA was 29.04 ± 24.94, and average % NMT was 50.47 ± 12.76. No significant correlation between RBH and % VB ( r  = 0.016; P  =   0.951), and RBH and % ( r  = 0.009; P  =   0.971) was found. Similarly, categorical analysis of correlation showed no statistical significance. Conclusion These findings suggest that the remaining alveolar bone height does not appear to influence the maturation and consolidation of an allograft in the maxillary sinus.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/93580/1/clr2270.pd

The effect of collagenated space filling materials in sinus bone augmentation: a study in rabbits

Aim: The inclusion of biomaterial particles used for alveolar bone regeneration in a carrier or in binding agents such as collagen gel or fibers is of interest as a means to help with surgical handling. However, the possible influence of collagen on bone tissue response to biomaterials is poorly studied. The objective of the present study was to investigate, in a sub-sinus bone augmentation model in rabbits, the effect of collagen at different stages of the osteogenesis process. Histologic, histomorphometric and volumetric analyses were performed. Materials and methods: Rabbits underwent a double sinus lift procedure using bovine hydroxyapatite (BHA), collagenated bovine hydroxyapatite (BHAColl), and prehydrated and collagenated porcine hydroxyapatite (PHAColl). Animals were sacrificed at 1 week, 5 weeks or 6 months. Samples were subjected to X-ray micro-tomography and histology. Qualitative analysis was performed on the non-decalcified sections and quantitative histomorphometric analyses were conducted using scanning electron microscopy (SEM). Volume variations of bone augmentations were calculated at different time points. Results: The three biomaterials allowed an optimal bone formation and were able to equally withstand sinusal reexpansion. A comparable percentage of new bone, as well as 3D volume stability, was found between the groups at each time point. However, the PHAColl resorption rate was significantly higher than the rates in other groups (P = 0.0003), with only 3.6% of the particles remaining at 6 months. At 1 week, both collagenated groups displayed the presence of inflammatory cells although BHA did not show any sign of inflammation. At 5 weeks and 6 months, the inflammatory process had disappeared completely in the BHAColl groups, whereas some inflammatory-like cells could still be observed around the remaining particles of PHAColl. Conclusions and clinical implications: Within the limitations of this study in rabbits, the findings showed the presence of inflammatory-like cells at the early stage of bone regeneration when collagenated xenogenic biomaterials were used compared to xenogenic granules alone. Nevertheless, similar bone formation occurred and comparable 3D volumes were found at 6 months in the different groups