Resistance of Mandibular Polyurethane Replicas to Fracture After Removal of Blocks From the Symphysis and Ramus.
BACKGROUND
When block grafts are harvested intraorally, the donor sites may act as stress concentrators and alter the structural integrity of the mandible.


OBJECTIVE
The study aimed to compare displacement and load failure between intact polyurethane mandibular replicas and similar replicas from which blocks were taken at the symphysis or the ramus. It also aimed to identify trends of load failure.


METHODS
Thirty-five mandibular replicas were tested to failure with an electromagnetic material testing unit. The variables evaluated in this investigation were maximal load, displacement at maximal load, and fracture location.


RESULTS
Statistically significant differences in maximal load were detected between groups (P = 0.0008). Differences between fracture locations were also statistically significant (P < 0.0001). The mandibles from which blocks were removed at the symphysis were significantly more likely to break at a lower maximal load than were the control mandibles (P = 0.0010) or the mandibles from which blocks were removed at the ramus (P = 0.0162). They were also more likely than the control group to break at a lower displacement at maximal load (P = 0.0145).


CONCLUSIONS
Location of the donor site significantly influences the structural integrity of mandibular replicas. In addition, the donor site significantly affects the location of mandibular fractures.
*Division Chief and Graduate Program Director of Periodontology, Department of Oral Health Practice, University of Kentucky College of Dentistry, Lexington, KY. †Professor, Department of Periodontology, School of Dental Medicine, Stony Brook University, Stony Brook, NY. ‡Past periodontal resident, Department of Oral Health Practice, University of Kentucky College of Dentistry, Lexington, KY. §Professor, Department of Biomedical Engineering; Associate Dean for Research and Graduate Studies, College of Engineering, University of Kentucky, Lexington, KY. ¶Associate Dean for Clinical Administration and Patient Care, The Ohio State University College of Dentistry, Columbus, OH. ‖Former Chair and Professor, Department of Oral Health Practice, University of Kentucky College of Dentistry, Lexington, KY.
Mohanad
M
Al-Sabbagh
Georgios
G
Romanos
Scott R
SR
Price
David A
DA
Puleo
Fonda G
FG
Robinson
Mark V
MV
Thomas
D001696:Biomechanical Phenomena; D016025:Bone Transplantation / Q000379:methods; D003799:Dental Stress Analysis; D008337:Mandibular Fractures / Q000503:physiopathology*; D008422:Materials Testing; D008953:Models, Anatomic; D011140:Polyurethanes / Q000737:chemistry*
D011140:Polyurethanes