The Study Of Expression Of NGF In Trigeminal Ganglion During Experimental Tooth Movement Of The Rat Molar

The treatment of malocclusion has been more than one hundred years, but the mechanism of a serial of changes and reactions in orthodontics has not been understood exactly. It has been thought that there are many factors involved in different stages of teeth movement.Nerve growth factor (NGF) is one of neurotrophins. It affects both on nervous and non-nervous system. It has been well known that NGF affects occurrence of inflammation pain and organism restoration. Generally, pain would occur during the beginning of force applied. Alveolar bone of the compressed area would be absorbed with the last of force and that of the tension area formed, then teeth moved. In view of the role of NGF may involve pain and organism restoration, we assume NGF might play an important role during orthodontic teeth movement. Trigeminal ganglia are main sensory nerve of face. It has been reported that the expression changes of NGF in trigeminal ganglia after teeth injured. However, the expression changes of NGF in trigeminal ganglia during orthodontic teeth movement keep to being unknown.105 adult male SD rats were divided into control group, sham experimental group and experimental group. Above groups were divided into 1, 3, 5, 7, 9, 14, 21 days sub-groups. Force was applied to first maxillary molars of right side which analyzed teeth movement. The expression changes of NGF in trigeminal ganglia were investigated by immunohistochemistry, in order to know the intercourse of NGF and orthodontic teeth movement.Results:After force applied on teeth, NGF expression increased greatly and heightened to maximum in the group of 3 days. From the groups of 5 to 21 days, the NGFexpression descended gradually, but was higher than that of control groups.This investigation showed NGF expression increased greatly at the beginning of force applied, which may be related to orthodontic pain. NGF expression descended gradually later, but was higher than that of control groups, which suggested NGF might be involved in regeneration of alveolar bone.