The load-deformation curves obtained by extraction of the rat maxillary first molar from its socket in the dissected jaw were analyzed so that the effect of orthodontic retention on the mechanical properties of the periodontal ligament could be examined. An elastic band was inserted between the rat maxillary first and second molars for four days, and then the interdental space was filled with resin for four or eight days. The average interdental spaces between the teeth ranged from 315 to 398 μm during the experimental period. The maximum shear load, elastic stiffness, and failure energy in shear decreased markedly following application of an orthodontic force, but they increased gradually and reached control levels on the 8th day after the retention. Maximum shear deformation at maximum load was not significantly different between the experimental and control teeth during the experimental period. It is suggested that, following orthodontic tooth movement, occlusal function was restored after a relatively short retention period, as was the impaired mechanical strength of the periodontal ligament.
Get full access to this article
View all access options for this article.
References
1.
Azuma M. (1970). Study on histologic changes of periodontal membrane incident to experimental tooth movement. Bull Tokyo Med Dent Univ17:149-178.
2.
Baumrind S. (1969). A reconsideration of the propriety of the "pressure-tension" hypothesis. Am J Orthod55:12-22.
3.
Chiba M., Kinoshita Y., Nakamura G., Ohshima S., Ishikawa S., Tsuruta M., Ozawa M. (1982). Effects of storage of jaws in saline and of velocity of loading on the force required to extract the rat mandibular first molar . Arch Oral Biol27:905-907.
4.
Chiba M., Komatsu K. (1988). In vitro estimation of the resistingforce of tooth eruption and the zone of shear in the rat incisor periodontal ligament. In: Davidovitch Z, editor. The biological mechanisms of tooth eruption and root resorption. Birmingham (AL): EBSCO Media, 193-205.
5.
Chiba M., Ohkawa S. (1980). Measurement of the tensile strength of the periodontium in the rat mandibular first molar. Arch Oral Biol25 :569-572.
6.
Chiba M., Ohshima S., Kuroda T., Ohkawa S. (1981). Effects of repeated shortenings and of artificial restraint on the tensile strength of the periodontium of the rat mandibular incisor. Arch Oral Biol26:135-141.
7.
Chiba M., Ohshima S., Takizawa K.( 1980). Measurement of the force required to extract the mandibular incisor of rats of various ages. Arch Oral Biol25:683-687.
8.
Chiba M., Yamane A., Ohshima S., Komatsu K. (1990). In vitro measurement of regional differences in the mechanical properties of the periodontal ligament in the rat mandibular incisor. Arch Oral Biol35:153-161.
9.
Cohn SA ( 1965). Disuse atrophy of the periodontium in mice. Arch Oral Biol10:909-919.
10.
Diaz EA ( 1978). Periodontal ligament collagen response to tooth movement: histochemical and autoradiographic reactions. Am J Orthod73 :443-458.
11.
Engstrom C., Granstrom G., Thilander B. (1988). Effect of orthodontic force on periodontal tissue metabolism. A histologic and biochemical study in normal and hypocalcemic young rats. Am J Orthod Dentofac Orthop93:486-495.
12.
Fogdestam I., Gottrup F. (1980). Biomechanical methods in wound-healing research with special reference to skin and gastrointestinal tract. In: Viidik A, Vuust J, editors. Biology of collagen. London (UK): Academic Press, 363-371.
13.
Graber TM (1972). Orthodontics. Principles and practice. 3rd ed. Philadelphia (PA): W.B. Saunders Company, 516-518.
14.
Haut RC ( 1986). The influence of specimen length on the tensile failure properties of tendon collagen. J Biomechan19:951-955.
15.
Hong RK ( 1990). The effects of orthodontic forces on the mechanical properties of the periodontal ligament in the rat maxillary molars. Am J Orthod Dentofac Orthop98:533-543.
16.
Kanoza Rjj, Kelleher L., Sodek J., Melcher AH (1980). A biochemical analysis of the effect of hypofunction on collagen metabolism in the rat molar periodontal ligament. Arch Oral Biol25:663-668.
17.
Kinoshita Y., Tonooka K., Chiba M. (1982). The effect of hypofunction on the mechanical properties of the periodontium in the rat mandibular first molar. Arch Oral Biol27:881-885.
18.
Komatsu K. (1988). In vitro mechanics of the periodontal ligament in impeded and unimpeded rat mandibular incisors. Arch Oral Biol33:783-791.
19.
Kuitert RB, van de Velde JP, Hoeksma JB, Prahl-Andersen B (1988/89). Tissue changes in the rabbit periodontal ligament during orthodontic tooth movement. Acta Morphol Neerl-Scand26:191-206.
20.
Macapanpan LC, Weinmann JP, Brodie AG (1954). Early tissue changes following tooth movement in rats. Angle Orthod24:79-95.
21.
MandelU.,DalgaardP.,ViidikA.( 1986). A biomechanical study of the human periodontal ligament . J Biomechan19:637-645.
22.
Martinez RH, Johnson RB (1987). Effects of orthodontic forces on the morphology and diameter of Sharpey fibers of the alveolar bone of the rat. Anat Rec219:10-20.
23.
Moyers RE (1975). Handbook of orthodontics for the student and general practitioner. 3rd ed. Chicago (IL): Year Book Medical Publishers, 438-442.
24.
Ohkawa S. (1982). Effects of orthodontic forces and anti-inflammatory drugs on the mechanical strength of the periodontium in the rat mandibular first molar. Am J Orthod81:498-502.
25.
Ohshima S. (1982). Effects oflathyrogens on the mechanical properties ofthe periodontium in the rat mandibular incisor. Tsurumi Univ Dent J8 :345-356.
26.
Ohshima S., Komatsu K., Yamane A., Chiba M. (1991). Prolonged effects of hypofunction on the mechanical strength of the periodontal ligament in rat mandibular molars. Arch Oral Biol36:905-911.
27.
Ohshima S., Nakamura G., Chiba M. (1989). Effects of lathyrogens on the mechanical strength of the periodontal ligament in the rat mandibular first molar. J Periodont Res24:343-350.
28.
Reitan K. (1954). Tissue reaction as related to the age factor. Dent Rec74:271-278.
29.
Reitan K. (1959). Tissue rearrangement during retention of orthodontically rotated teeth. Angle Orthod29:105-113.
30.
Reitan K. (1960). Tissue behavior during orthodontic tooth movement . Am J Orthod46:881-900.
31.
Reitan K. (1964). Effects of force magnitude and direction of tooth movement on different alveolar bone types. Angle Orthod34:244-255.
32.
Reitan K. (1967). Clinical and histologic observations on tooth movement during and after orthodontic treatment. Am J Orthod53:721-745.
33.
Reitan K. (1975). Biomechanical principles and reactions. In: Graber TM, Swain BF, editors. Current orthodontic concepts and techniques . 2nd ed. Philadelphia (PA) : W.B. Saunders Company, 111-229.
34.
Riedel RA (1960). A review of the retention problem. Angle Orthod30 :179-199.
35.
Roberts WE, Jee Wss (1974). Cell kinetics of orthodontically-stimulated and non-stimulated periodontal ligament in the rat. Arch Oral Biol19:17-21.
36.
Rygh P. ( 1977). Orthodontic root resorption studied by electron microscopy . Angle Orthod47:1-16.
37.
Schwarz AM (1932). Tissue changes incidental to orthodontic tooth movement. Int J Orthod Oral Surg Radiogr18:331-352.
38.
Tanaka T., Morioka T., Ayasaka N., Iijima T., Kondo T. (1990). Endocytosis in odontoclasts and osteoclasts using microperoxidase as a tracer. J Dent Res69:883-889.
39.
Tsuruta M., Ohkawa S., Nakatani Y., Kuwahara Y., Chiba M. (1982). Effect of experimental tooth movement on the mechanical strength of the periodontium in the rat mandibular first molar. Arch Oral Biol27 :875-879.
40.
Waldo CM, Rothblatt JM (1954). Histologic response to tooth movement in the laboratory rat. Procedure and preliminary observations. J Dent Res33:481-486.
41.
Zaki AE, van Huysen G. (1963). Histology of the periodontium following tooth movement. J Dent Res42:1373-1379.
