back to contentsExperimental study on theeffect of Chinese herb (Erigeron Breviscapus Co.) on toothmovement in young rabbit
Hong-hu LIU and Kooji HANADA*
Department of Orthodontics, School of Stomatology,Shanghai Second Medical University, Shanghai (Chief : Prof. KaanLIU)
* Department of Orthodontics, Niigata University, School ofDentistry (Chief)
Abstract ;
One of the important problems in orthodontic treatment is howtreatment time can be shorten. This problem may be solved bytreatment with an efficient procedure or by rapid tooth movementwith a drug. In the latter, prostaglandin E2 ( PGE2 ) or ErigeronBreviscapus Co. ( EBC ) are known to be used with intragingivalinjection. However, it is impossible to avoid a pain utilizingthis injection method. On the other hand, an ionophoresis methodcan osmose a drug solution to deep the periodental tissue withouta pain.
In the present study, EBC was administerred during tooth movementin a young rabbit with an ionophoresis method or intragingivalinjection. Then, the total distance of tooth movement andhistological findings in the periodontal tissue were comparedamong these groups.
Materials and methods : 50 young rabbits were used. According tothe method of administration of EBC, PGE2, or physiologicalsaline, the animals were divided into 5 groups of ten. Lowerincisors of each animal were moved for 14 days with open helicalloop fabricated by an orthodontic wire so as to generate 50 g ofinitial force. The positive pole or the negative one in eachionphoresis group was established to lower labial area or a lefthand, respectively, and then 0.4 ml of each drug solution wasadministerred under 0.2 mA for 15 minutes per one time. On theother hand, the same amount of each drug solution in eachinjection group was injected into a gingival tissue in the labialside between left and right lower incisors. Administration ofeach drug was executed at 2nd, 4th, 6th, 8th, 10th and 12th dayafter the beginning of tooth movement. After measuring thedistance of tooth movement at 14th day of treatment, the animalswere killed. Then, the jaws were demineralized in formate-citratesolution for 10 days, and serial paraffin sections, 7μm inthickness, were cut on a microtome. After that, these sectionswere stained with H-E for light microscopic observation.
Results : Average distance of tooth movement in EBC group with anionophoresis method was 4.28 mm and significantly longer thanthat in any other group ( P<0.05 ). With respect tohistological findings, the number of blood vessels in the tensionsite of the periodontal ligament was prone to increase especiallyin EBC ionphoresis group. Alveolar bone formation in the tensionsite was also more active in this group. On the other hand, asignificantly more bone resorptive lacunae in the compressionsite were observed in EBC ionophoresis group as compared to anyother group.
These findings mentioned above demonstrate that EBCadministration with an ionphoresis method appears to evoke moreactive bone remodeling during tooth movement. Therefore, it ispossible that EBC may be useful in efficient tooth movement inthe orthodontic field.