Three-Dimensional Assessment of Volumetric Changes in Sinuses Augmented with Two Different Bone Substitutes

Abstract

Introduction. The bone volume of the posterior maxilla may not be appropriate for implant placement, due to factors such as pneumatized maxillary sinus. The purpose of this study was to evaluate the percentage of graft volume reduction following sinus floor elevation (SFE), with either slow resorbable bone substitute only or a composite of slow and fast resorbable bone substitutes, using cone beam computed tomography (CBCT). Materials and Methods. In this retrospective study, CBCT scans of SFE procedures were evaluated to determine the volume of grafted sinus with either deproteinized bovine bone (DBB) or a 2 : 1 mixture of biphasic calcium sulfate (CS) and DBB, as a composite. The volumetric changes of sinus augmentations were measured 2 weeks (V-I) and 6 months (V-II) after operation. Results. Thirty-three patients were included in this study. The average percentage volume reduction was 9.39 ± 3.01% and 17.65 ± 4.15% for DBB and composite grafts, respectively. A significant graft volume reduction was observed between V-I and V-II for both groups (p < 0.01). The DBB group exhibited significantly less volume reduction than the composite group (p < 0.01). Conclusions. Augmented sinus volume may change before implant placement. DBB offers greater volume stability during healing than composite grafts.

Figure 1

Crestal and vertical releasing buccal incisions were made along the residual alveolar bone.

Figure 2

An osteotomy was performed on the buccal sinus wall using diamond rotary instruments or a piezosurgical device. The bone at the center of the access window was gently fractured, and the intact sinus membrane was gently elevated with proper instruments.

Figure 3

Patients requiring SFE underwent grafting procedures using either deproteinized bovine bone (DBB) or a 2 : 1 mixture of biphasic CS and DBB as a composite.

Figure 4

The lateral window was then covered and tacked with resorbable collagen membrane.

Figure 5

The mucosal flap was replaced with nonabsorbable monofilament material for primary closure.

Figure 6

Digital reconstruction was performed by selecting the grafted volume, whereas manual reconstruction was based on threshold values selected according to the gray values of native bone, grafted bone, soft tissue, and sinus cavity, expressed on the software program.

Figure 7

The volume of the three-dimensional grafted biomaterial was calculated.

Figure 8

Box plot of percentages of reduction in bone graft volume in the experimental groups after 6 months. DBB, deproteinized bovine bone; composite, 2 : 1 mixture of biphasic CS and DBB.