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The biomechanical properties of the healing periodontium of replanted rat mandibular incisors
Author(s) -
Shinohara Josuke,
Shibata Tatsuya,
Shimada Akemi,
Komatsu Koichiro
Publication year - 2004
Publication title -
dental traumatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 81
eISSN - 1600-9657
pISSN - 1600-4469
DOI - 10.1111/j.1600-9657.2004.00244.x
Subject(s) - periodontal fiber , periodontium , tooth replantation , replantation , dentistry , incisor , medicine , dental alveolus , orthodontics , anatomy , resorption , root resorption , pathology
– One of the most important aspects in tooth replantation seems to be restoration of the tooth support function of the healing periodontal ligament (PDL). We examined the support function, as measured by the mechanical properties, of the healing PDL at 7, 14, and 21 days after replantation of the left mandibular incisor in rats. From each dissected left mandible, a transverse section(650 µm in thickness) of the incisor was cut through an axis near the labial alveolar crest. Each section was intrusively loaded at a rate of 5 mm min −1 , and the shear stress–strain curve for the PDL was analyzed. Mechanical measures of the healing PDL showed gradual improvement after replantation. By 21 days, the mechanical strength returned to 53% of the control value; the extensibility, to 85%; the stiffness, to 61%; and the toughness, to 52%. The healing PDL exhibited reattachment of fibers in the middle region of the PDL, and the birefringent collagen fibers appeared to have regained the functional orientation by 14 days. The ratios occupied by the birefringent collagen fibers in the tooth‐related, middle, and bone‐related areas of the healing PDL gradually improved and returned to 78, 51, and 48% of the respective control values by 21 days. These results suggest that the support function of the healing PDL is gradually restored and that the biomechanical restoration is closely related to the reorganization and reorientation of collagen fiber bundles in replanted rat incisors.