Influence of the contact area of the sub-antral space with sinus bone and the Schneiderian membrane on osteogenesis in lateral window sinus elevation surgery: a prospective experiment

Abstract

Background: Osteogenesis of lateral window sinus elevation surgery is the key to placement of the subsequent implant, excessive collapse of the sub-antral space may adversely affect long-term stability of implants. At present, few studies focus on the influence of the contact area of the sub-antral space on osteogenesis. This study evaluated whether the change in the contact area of the sub-antral space with maxillary sinus bone and the Schneiderian membrane can affect osteogenesis.

Methods: Cone beam computed tomography (CBCT) images were collected of patients requiring maxillary sinus floor elevation (residual bone height < 6 mm) for standard-length implant placement before surgery, after surgery, and at 6-month follow-up visits. The postoperative sub-antral space volume (V₁) and surface area (S₁), and the remaining volume after six months of healing (V₂) were measured. Then, the contact area of sub-antral space with maxillary sinus bone (S_bc) and the Schneiderian membrane (S_mc), the absorbed volume during healing (V_a), and the percentage of remaining volume (V₂%) and absorbed volume (V_a%) were calculated. The correlation between anatomical parameters was analyzed using multiple linear regression.

Results: A total of 62 maxillary sinuses from 56 patients were augmented, of which 57 were considered for the final analysis (5 withdrew due to perforation). Multiple linear regression results demonstrated that S_bc was significantly positively correlated with V_a (β coefficient = 0.141, p < 0.01) without correlation between S_mc and V_a (β coefficient = - 0.046, p = 0.470). There was a positive correlation between S_bc and V₂% (β coefficient = 2.269, p < 0.05).

Conclusions: This study confirmed that the size of the S_bc in lateral window sinus elevation surgery affected osteogenesis after six months of healing. Clinicians should assess the sinus contour type preoperatively, then consider whether it is necessary to expand the range of the Schneiderian membrane elevation to avoid excessive collapse of the sub-antral space.

Trial registration: Chinese Clinical Trial Registry (ChiCTR), ChiCTR2200057924. Registered 22 March 2022-Retrospectively registered.

Keywords: Bone regeneration; CT imaging; Clinical research; Maxillary sinus; Sinus floor elevation.

Fig. 1

Intraoperative photos. A and B from group A: Simultaneous implantation after completing sinus elevation; C and D from group B: Only sinus elevation was completed during the first surgery

Fig. 2

Volume and surface area analysis was performed using Mimics. A “Green mask” of the sub-antral space was created as the region of interest. A–C: the coronal, axial and sagittal planes of sub-antral space. D: A 3-dimensional model, including sub-antral space (green), bone tissue around maxillary sinus (yellow) and some nearby teeth (white)

Fig. 3

Contact area analysis using Mimics. A Sub-antral space was divided into two parts according to its contact relationship with maxillary sinus bone wall and the Schneiderian membrane, (a) the Schneiderian membrane, the red line marks its lower boundary, (b) maxillary sinus bone. B The sub-antral space that in contact with the Schneiderian membrane (c). C the sub-antral space that in contact with maxillary sinus bone (d)

Fig. 4

Contact relationship between sub-antral space and surrounding tissue. S_mc: the contact area of sub-antral space with schneiderian membrane. S_r: the surface area of the removed lateral bone wall. S_bc: the contact area of sub-antral space with maxillary sinus bone. S_j: the surface area of an imaginary plane, which divides the sub-antral space into upper and lower parts, the upper part contacts the Schneiderian membrane, while the lower part contacts the sinus bone

Fig. 5

Contents of sub-antral space. a Bio-oss, b CGF and blood, c air

Fig. 6

Comparison of the contact area between sub-antral space and sinus bone after sinus membrane elevation for maxillary sinus with different contours. Yellow line represents the contact area. A: narrow tapered, B: square

Fig. 7

The implant is in contact with the sinus membrane due to the absorption of graft material