Joanne S. Kim

Abstract

Introduction: Regenerating bone in critical-sized maxillofacial osseous defects remains a challenge. The utilization of recombinant human bone morphogenetic protein-2 (rhBMP-2) to form new bone has been shown to be a promising alternative to autogenous bone grafts, and the development of a carrier matrix to effectively deliver the rhBMP-2 has been identified as the critical factor necessary for the successful clinical application of rhBMP-2. The objective of this study was to perform a microCT analysis to examine the density of reconstructed bone using different rhBMP-2 carriers in critical-sized defects.

Material and Methods: Critical-sized defects (approximately 2.5 cm) were created in the mandibles of 13 adult male non-human primates. Each side of the mandibles received one of four carrier types: A) 1.5 mg/cc rhBMP-2 combined with an absorbable collagen sponge (ACS), B) 15% hydroxyapatite (HA) and 85% beta-tricalcium phosphate (β-TCP) spheres wrapped with an absorbable collagen sponge (ACS) and 1.5 mg/cc rhBMP-2, C) Compression resistant matrix (CRM) with 2.0 mg/cc rhBMP-2, and D) CRM with .75 mg/cc rhBMP-2. One control animal received CRM alone, and the resected original bone from this animal was also made available for analysis. A 3-D microCT analysis was performed using an imaging software (Amira 5.2.2; Visage Imaging, Inc, Carlsbad, CA) to measure the bone density of the newly regenerated bone in relative Hounsfield units (rHUs) from specific regions of interest (ROIs). Means and standard deviations of all variables were calculated. Sebeffe's test at the significance level of α = 0.05 was used for statistical analysis.

Results: A high intra-examiner reliability of measurements (ICC = .922 - .995) was observed. While groups B, C, and D formed bone with densities that were not statistically different from one another, they were significantly denser than regenerated bone formed in Group A (p < .05). The superior section of bone in groups B, C, and D was found to be significantly denser than the inferior section (p < .05).

Conclusions: MicroCT analysis provided for objective measurements of bone density. Using an rhBMP-2 carrier consisting of a collagen sponge and 15:85 HA-β-TCP was more effective in producing bone of higher density than using a collagen sponge alone. A low dose of rhBMP-2 (0.75 mg/cc) was as effective as a high dose (2.0 mg/cc) when utilizing CRM to form new bone.

LLU Discipline

Orthodontics and Dentofacial Orthopedics

Department

Orthodontics and Dentofacial Orthopedics

School

Graduate Studies

First Advisor

Joseph M. Caruso

Second Advisor

Alan S. Herford

Third Advisor

Kitichai Rungcharassaeng

Degree Name

Master of Science (MS)

Degree Level

M.S.

Year Degree Awarded

2010

Date (Title Page)

9-2010

Language

English

Library of Congress/MESH Subject Headings

Bone Regeneration; Bone Morphogenetic Protein 2; Bone Morphogenetic Proteins -- administration & dosage; Bone Density -- physiology; Recombinant Proteins -- administration & dosage; Mandible -- surgery; Reconstructive Surgical Procedures -- methods; Bone Transplantation; Surgical Sponges; Drug Carriers; X-Ray Microtomography; Animals, Laboratory

Type

Dissertation

Page Count

xi; 46

Digital Format

PDF

Digital Publisher

Loma Linda University Libraries

Usage Rights

This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.

Collection

Loma Linda University Electronic Theses and Dissertations

Collection Website

http://scholarsrepository.llu.edu/etd/

Repository

Loma Linda University. Del E. Webb Memorial Library. University Archives

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