The effect of chitosan bead encapsulating calcium sulfate as an injectable bone substitute on consolidation in the mandibular distraction osteogenesis of a dog model.
OBJECTIVE
The purpose of this project was to study the effect of chitosan bead encapsulating calcium sulfate, which provides a sustained release of chitosan and calcium sulfate after implantation, on early bony consolidation in distraction osteogenesis of a dog model.


METHODS
Forty-five dogs were used for this study. An external distraction device was applied to the mandibular body after a vertical osteotomy and mandibular distraction was initiated 5 days after the operation at a rate of 1 mm/day up to a 10-mm distraction. The experimental group was divided into a control group (I), hyaluronic acid group (II), chitosan group (III), calcium sulfate group (IV), and chitosan bead encapsulating calcium sulfate group (V). Normal saline was injected in group I. In group II, 1 mL of hyaluronic acid solution was injected into the distracted region. In group III, 1 mL of injectable solution of chitosan mixed with hyaluronic acid was implanted. In group IV, 1 mL of injectable solution of calcium sulfate mixed with hyaluronic acid was implanted. In group V, an injectable form of powdered chitosan bead encapsulating calcium sulfate mixed with 1 mL volume of hyaluronic acid was implanted.


RESULTS
Bone mineral density was 12% of the contralateral normal mandible at 3 weeks, 23.4% at 6 weeks in group I, 15% at 3 weeks, 29.1% at 6 weeks in group II, 16% at 3 weeks and 32% at 6 weeks in group III, 30.4% at 3 weeks and 52.8% at 6 weeks in group IV, and 33.6% at 3 weeks and 55% at 6 weeks in group V with statistical significance (P < .005). The mean 3-point failure load was compared with the intact contralateral mandible and noted to be 12% in the control group, 16% in group II, 18% in group III, 34.3% in group IV, and 31.7% in group V. Difference of mean percentages between one group and another was statistically significant (P < .005). In the histologic findings, new bone was generated in all groups. In groups IV and V, the formation of active woven bone was observed throughout the distracted region at 6 weeks. The amount of new bone formation in the distracted zone was in the order of group IV and V, III and II, and the control group.


CONCLUSIONS
These findings suggest that chitosan bead encapsulating calcium sulfate appears to facilitate early bony consolidation in distraction osteogenesis.
Cho
Byung Chae
BC
Department of Plastic and Reconstructive Surgery, College of Medicine, Kyungpook National University, Daegu, Korea. bccho@knu.ac.kr
Chung
Ho Yun
HY
Lee
Dong Gul
DG
Yang
Jung Duk
JD
Park
Jae Woo
JW
Roh
Kyung Ho
KH
Kim
Go Un
GU
Lee
Dong Sin
DS
Kwon
Ick Chan
IC
Bae
Eun Hee
EH
Jang
Kwang Ho
KH
Park
Rang Woon
RW
Kim
In San
IS
D000704:Analysis of Variance; D000818:Animals; D015519:Bone Density; D001861:Bone Regeneration; D018786:Bone Substitutes / Q000008:administration & dosage*; D002133:Calcium Sulfate / Q000008:administration & dosage; D048271:Chitosan / Q000008:administration & dosage; D003799:Dental Stress Analysis; D004285:Dogs; D006820:Hyaluronic Acid / Q000008:administration & dosage; D008334:Mandible / Q000601:surgery*; D019186:Mandibular Advancement / Q000379:methods*; D008863:Microspheres; D023421:Models, Animal; D019857:Osteogenesis, Distraction; D018583:Pliability
D018786:Bone Substitutes; D006820:Hyaluronic Acid; D048271:Chitosan; D002133:Calcium Sulfate