Effect of systemic parathyroid hormone (1-34) and a β-tricalcium phosphate biomaterial on local bone formation in a critical-size rat calvarial defect model

Yun JI, Wikesjö UME, Borke JL, Bisch FC, Lewis JE, Herold RW, Swiec GD, Wood JC, McPherson III JC. Effect of systemic parathyroid hormone (1–34) and a β‐tricalcium phosphate biomaterial on local bone formation in a critical‐size rat calvarial defect model. J Clin Periodontol 2010; 37: 419–426 doi: 10.1111/j.1600‐051X.2010.01547.x Objective: The objective of this study was to evaluate local bone formation following systemic administration of parathyroid hormone (1–34) (PTH), a surgically implanted synthetic β‐tricalcium phosphate (β‐TCP) bone biomaterial serving as a matrix to support new bone formation. Materials and Methods: Critical‐size, 8 mm, calvarial through‐and‐through osteotomy defects were surgically created in 100 adult male Sprague–Dawley rats. The animals were randomized into five groups of 20 animals each to receive one of the following treatments: PTH (15 μg PTH/kg/day; subcutaneously), PTH/β‐TCP, β‐TCP, or particulate human demineralized freeze‐dried bone (DFDB), and sham‐surgery controls. Ten animals/group were euthanized at 4 and 8 weeks post‐surgery for radiographic and histometric analysis. Results: The histometric analysis showed that systemic PTH significantly enhanced local bone formation, bone fill averaging (±SE) 32.2±4.0% compared with PTH/β‐TCP (15.7±2.4%), β‐TCP (12.5±2.3%), DFDB (14.5±2.3%), and sham‐surgery control (10.0±1.5%) at 4 weeks (p