Distal Displacement of Maxillary Sinus Anterior Wall Versus Conventional Sinus Lift with Lateral Access: A 3-Year Retrospective Computerized Tomography Study

Abstract

Background: The present study is designed to compare the outcomes of two sinus augmentation procedures: distal displacement of the anterior wall versus standard sinus lifting and grafting with a lateral window approach.

Methods: In the displacement group, a localized surgical fracture of the sinus floor achieved through an electromagnetic device results in the distal displacement of the anterior wall. In the filling group, sinus lifting (with lateral access) and grafting with particulate xenogeneic bone substitute was performed. Bone volume beneath the maxillary sinus was investigated with computerized tomography after baseline and postoperative data superimposition. Clinical and radiological outcomes over three years had been evaluated.

Results: Forty-three dental implants were selected. The two sinus lift procedures significantly increased the bone volume (p-value ≤ 0.0017) in the displacement group from 1.17 ± 0.34 to 1.53 ± 0.39 cc, with a final bone gain of +0.36 ± 0.17 cc, and in the filling group from 1.24 ± 0.41 to 1.94 ± 0.68 cc, with a bone augmentation of +0.71 ± 0.31 cc. No events of dental implant bulging into the maxillary sinus occurred. Two implants failed early on in the filling group, attesting the 3-year survival rate of 92.6% (CI95%: 82.7-100%). Marginal bone loss at the distal aspect was 1.66 ± 0.72 and 1.25 ± 0.78 mm, respectively, for the displacement and filling groups, with a significant difference (p-value = 0.0497).

Conclusion: Results showed a significant and effective bone gain around dental implants at a 3-year survey for both sinus augmented by backward displacement of the anterior wall (+34%) and sinus lifting and grafting with a lateral window approach (+57%).

Keywords: CT imaging; bone augmentation; dental implant; infracture approach; maxillary sinus.

Figure 1

Augmented sinus by backward displacement technique of the anterior wall: (A,B) Procedure scheme for the surgical treatment; (C,D) clinical photograph showing the edentulous ridge of the maxilla with expansion devices in action.

Figure 2

Augmented sinus by lifting and grafting with a particulate bone substitute with a lateral window approach: (A) Exposure of the crest with full-thickness flap with osteotomies; (B) dental implants placed in sinus lifted and grafted with xenogeneic bone substitute material; (C) surgical site covered by reabsorbable membrane; (D) clinical view of surgical procedure with final sutures of gingival margins.

Figure 3

Fontal and lateral views of an augmented sinus by a backward displacement technique of the anterior wall: (A) preoperative; (B) postoperative; (C) fused files. Fontal and lateral views of an augmented sinus by lifting and grafting with a particulate bone substitute with a lateral window approach: (D) preoperative; (E) postoperative; (F) fused files.

Figure 4

Box and wishers plot (with scattering data, O) of the volume at the preoperative stage (BVpreop) and at the 3-year survey (BV3yrs) of alveolar bone beneath the sinus, and their difference, ΔBV (with its percentage, %ΔBV) from the preoperative stage to the 3-year survey (preop→3yrs) in volume of interest (VOI). In box-and-whiskers plot the box line represents the lower, median and upper quartile values, the whisker lines include the rest of the data. Outliers (+) were data with values beyond the ends of the whiskers. Results for pair-wise statistical comparisons: Wilcoxon signed-rank test assessing changes in time from the preoperative stage to the 3-year follow-up (*); Wilcoxon rank-sum test assessing changes between groups (°).4. Discussion.