The Effect of Alendronate on Various Graft Materials Used in Maxillary Sinus Augmentation: A Rabbit Study

Abstract

Background: Increasing sinus pneumatization and the accompanying alveolar bone resorption complicate dental implant placement. This problem can be overcome today by raising the maxillary sinus floor with graft materials. Bisphosphonates are commonly used to accelerate the recovery of the graft materials and to prevent resorption.

Objectives: The purpose of this study is to investigate whether systemic administration of a bisphosphonate (alendronate) would improve new bone formation and reduce fibrous tissue formation over a 6-week follow-up in rabbits treated with two different grafting materials for maxillary sinus floor augmentation.

Materials and methods: This experimental animal study was conducted at the Experimental Medical Application and Research Center at Erzurum/ Turkey. Twelve New Zealand rabbits, each weighing between 2.7 and 3.3 kg, were used. Twenty-four maxillary sinus floor elevation operations were performed, two on each animal (n = 24). Each elevation was repaired with either deproteinized bovine bone (xenograft) or autogenous bone graft obtained from the iliac crest. Both groups were divided into 2 subgroups: saline-treated and alendronate-treated. All groups underwent the same surgical procedures and evaluation, and were sacrificed at the 6th postoperative week. Sinuses augmented with deproteinized bovine bone (xenograft) and autogenous bone graft were examined histopathologically and histomorphometrically.

Results: At 6 weeks, the bone area was significantly larger in the Xenograft-Alendronate group (33.0% ± 5.0%) than in the Xenograft-Saline group (20.8% ± 4.9%) and the bone area was significantly larger in the Autogenous-Alendronate group (43.3% ± 3.8%) than in the Autogenous-Saline group (37.5% ± 6.6%) (P = 0.001). The histomorphometric and histopathological results consistently showed that alendronate stimulated bone formation and reduced fibrous tissue formation in maxillary sinus augmentation grafts, especially in the deproteinized bovine bone group (xenograft).

Conclusions: Alendronate may be considered a therapeutic option for improving the bone formation process and reducing resorption in different bone grafting procedures. Further detailed studies should focus on dosage and time-dependent effects of alendronate on bone remodeling.

Keywords: Alendronate; Bisphosphonate; Maxillary; Sinus.

Figure 1.. The Defect Sites Were Filled With Grafting Materials

A, Autogenous bone graft; B, Cone-beam tomographic image immediately after surgery; D, Deproteinized bovine bone (xenograft); M, Maxillary Sinus; N, Nose.

Figure 2.. A, Control 10x; B, Control 20x; C, Alendronate 10x; D, Alendronate 20x; A - B, Illustration of new bone ossification areas for xenograft material in the control group; C - D, New bone ossification areas for xenograft material in the alendronate-treated group; (b, bone trabecular; f, fibrous tissue; bm, bone marrow cavity; d, vessel; open arrow, osteoclast cell; arrow head, osteocyte).

Figure 3.. A, Control 10x; B, Control 20x; C, Alendronate 10x; D, Alendronate 20x; A - B, Illustration of new bone ossification areas for autogenous bone grafts in the control group; C - D, New bone ossification areas for autogenous bone grafts in the alendronate-treated group; (b, bone trabecular; f, fibrous tissue; bm, bone marrow cavity; open arrow, osteoclast cell; d, vessel; arrow head, osteocyte).