Purpose: To analyze effect of an alternating distraction–compression protocol over conventional distraction osteogenesis (DO) protocol on new bone formation.
Materials and methods: Eighteen rabbits underwent bilateral mandibular corticostomy, custom-made distractor device placement, and application of distraction protocols for 15 days to a length of 6 mm. After a 5-day latency period, in each left hemimandible the conventional DO protocol (Group I, N = 18) was initiated at a rate of 0.2 mm twice a day, to a total length of 0.4 mm. In the opposite side the experimental DO protocol (Group II, N = 18) was done first by an over-distraction of 0.6 mm followed by a compression of 0.2 mm the next 12 h and setting same total length as the control side. After a consolidation period of 0 (Subgroup A, N = 2), 4 (Subgroup B, N = 8) and 8 weeks (Subgroup C, N = 8), bone data was obtain through plain radiography, micro-computed tomography, histomorphometric and immunohistochemical analysis.
Results: Bone-surface to bone-volume ratio (BS/BV) and structural model index (SMI) showed statistical significant differences ( p < .05) between the consolidation groups. Group II showed higher trabecular number (Tb.N) and separation (Tb.Sp), and BS/BV values than Group I. Among subgroups, Group IIB showed significantly differences ( p < .05) in osteoblast-covered bone surface (Ob.S/BS), relative fibrous tissue volume (Fb.V/TV), relative bone volume (BV/TV), and relative number of blood vessels (Bv.N/TV). Expression of BMP-4 was more intense in Group IIA and IIB and Osteocalcin in Group IIC.
Conclusion: Results suggest that an alternating distraction–compression protocol may enhance the regenerated distracted bone quantity and quality.
Conflict of interest: None declared.