[Relationship between tissular structure and strength of fresh bull periodontal ligament].
OBJECTIVE
To study the relationship between the width and the content of fiber in peridontal ligament (PDL) and the strength of peridontal membrane.


METHODS
Fresh mandible of bull was obtained to prepare for a 5 mm x 2 mm x 10 mm cuboid including teeth, peridontal membrane, and alveolar bone. The width of the PDL was measured under a stereomicroseope. Pull stress was loaded on the test piece until it broke. The stress-strain curve was recorded. The broken ends of the PDL was dyed with siriue to adalyze the content of fiber.


RESULTS
The relationship between the width of the PDL and the maximum stress was expressed as Y = 9.786e(-3.6693x). The relationship between the width of the PDL and the physiological ultimate stress was expressed as Y = e((2.188(-3.953)x). The relationship between the percentage of fiber and maximum stress was expressed as Y = 20.788-0.755x + 0.007x(2). The relationship between the percentage of fiber and the physiological ultimate stress was expressed as Y = 1.39e(-14) x x(7.666). The initial physiological stress was 0.28 N/mm2.


CONCLUSIONS
The strength of PDL increases with the decrease of PDL width and increase of fiber content.
Men
Qing-lin
QL
Key Laboratory of Oral Biomedical Engineering of Ministry of Education, Sichuan University, Chengdu 610041, China.
Chen
Xin-min
XM
Xu
Chao
C
Ren
Shi-peng
SP
Peng
Yan
Y
D000818:Animals; D002417:Cattle; D008297:Male; D008334:Mandible / Q000033:anatomy & histology / Q000502:physiology; D010513:Periodontal Ligament / Q000502:physiology* / Q000648:ultrastructure*; D013718:Tensile Strength