Guided bone regeneration using beta‐tricalcium phosphate with and without fibronectin—An experimental study in rats

Objective This histomorphometric study compared bone regeneration potential of beta‐tricalcium phosphate with fibronectin (β‐TCP‐Fn) in critical‐sized calvarial defects (CSDs) in rats to assess whether fibronectin (Fn) improved new bone formation. Material and methods Critical‐sized calvarial defects were created in 30 adult male Sprague Dawley rats, which were divided into four groups according to the time of euthanasia (6 or 8 weeks of healing) and type of filling (β‐TCP‐Fn/6 weeks, β‐TCP/6 weeks, β‐TCP‐Fn/8 weeks and β‐TCP/8 weeks). The primary variables related to new bone formation were augmented area (AA) and gained tissue (GT; sum of mineralized bone matrix [MBM] and bone substitute [BS]). Secondary variables were the diameter of the defect, MBM, non‐mineralized tissue (NMT) and BS. Results A total of 29 rats and 58 histological samples were evaluated, 28 (48.3%) samples obtained at 6 weeks and 30 (51.7%) at 8 weeks, homogeneously distributed between right and left sides. Thirteen (22.4%) were treated with β‐TCP‐Fn, 16 (27.6%) with β‐TCP and 29 (50%) were controls. At 8 weeks, histomorphometric analysis showed significant differences in AA using β‐TCP and β‐TCP‐Fn versus controls (p = 0.001 and p = 0.005, respectively). Bone turnover expressed as % within the target area was slightly higher but not statistically significant in the β‐TCP‐Fn than in β‐TCP (MBM) at 6 weeks versus 8 weeks (p = 0.067 and p = 0.335, respectively). Finally, the total GT area in mm2 was higher using β‐TCP‐Fn as compared to β‐TCP (p = 0.044). Conclusions β‐TCP‐Fn was slightly but non‐significantly more effective than β‐TCP without Fn for improving the volume of regenerated bone in CSDs of rats, possibly allowing a more efficient bone remodelling process. This effect however should continue being investigated.