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The aim of this study is to present an orthodontic appliance which move the upper first molars in rats mesially and to evaluate the results of this appliance with the findings of other researches. 20 Sprague Dawley rats 220±10 gr. in weight and 90±10 days of age were used in this study and NiTi coil springs were inserted between the first upper molar and incisor as the orthodontic appliance. Animals tolerated the experimental procedures well. Following an initial loss, they all regained their original weights. During the experimental period appliance breakage did not occur due to the continuos eruption of upper incisors or to the chewing function. At the end of the experimental period diastema between the first and second molar and food impaction in this area was seen. Histological examination showed that because of food impaction and the wire around the first upper molar pathological changes on alveolar bone occurred.Because of continuos eruption of upper incisors in rats applying the orthodontic appliance to the molars would have some advantages over the other appliances applied to the incisors. Difficulties in inserting the appliance and pathological changes on alveolar bone are two main disadvantages of this appliance.

The aim of this study is to evaluate the effect of different doses and the numbers of injections parathyroid hormone on the rate of tooth movement, alveolar bone and on Ca and P levels in blood. Fifteen male sprague dawley rats 220±10 gr. in weight and 90 days of age were used in this study. Orthodontic appliance were inserted on the upper first molar and different doses and numbers of parathyroid hormone were injected Tooth movement is measured on radiographs taken at the beginning and at the end of the experiment. All animals were killed at 14 th. day of the experiment. The heads were dissected and processed for histological examination, blood serum was tested for the level of Ca and P. The fastest tooth movement occurred after local injection of 17 pgr. of parathyroid hormone 3 times. There was no difference in blood Ca and P levels between control and experimental animals. Histologically .there was no pathological changes on alveolar bone due to the local injection of parathyroid hormone.