Effect of Simvastatin on Guided Bone Regeneration

Objectives: Expensive biologic agents have been used in conjunction with guided bone regeneration to improve outcomes. The hypothesis of this study was that addition of simvastatin, a generic cholesterol-lowering drug with bone anabolic properties, could augment guided bone regeneration in a dog model. Methods: Four adult beagle dogs were anesthetized, mucoperiosteal flaps reflected facial of both mandibular 1st molars, and a 10 x 5 x 3 mm hydroxyapatite/collagen graft (Bio-Oss Collagen, one side randomly soaked in 10 mg simvastatin/ethanol [SIM], the other side soaked in 70% ethanol alone [control]) was placed along the marginal bone. Grafts were covered by a resorbable bilayer collagen membrane (Bio Gide) secured with a sling suture, and the flaps readapted with 4-0 gut sutures. Dogs were euthanized after 2 months, molars and surrounding soft tissue removed, decalcified, 5 µm buccal-lingual sections (3/site) were cut through the mesial-buccal root, and stained with hematoxylin and eosin. Histomorphometrical measurements by 2 masked evaluators were compared between sides using analysis of variance. Results: Thickness of bone over the mesial root increased in both SIM and control groups as measured at the alveolar crestal bone (0.56 ± 0.09 mm) and 4 mm apically (1.07 ± 0.09 mm, p < 0.0001). However, the alveolar crest was located more coronally (< 1 mm from CEJ) in the grafts with added simvastatin (2.35 ± 0.10 vs. 2.51 ± 0.10 mm from reference marker, p = 0.038). Surrounding soft tissues on both sides had minimal inflammatory infiltrate (< 1% of connective tissue area). Conclusions: In this pilot study, addition of simvastatin to hydroxyapatite/collagen grafts covered by collagen membranes appears to have a positive influence on periodontal bone height following surgery, which should be evaluated further in other periodontal and peri-implant conditions. Supported by UNMC College of Dentistry and Surgical Specialties Postgraduate Fund.