Study On The Clinical Effect Of Site Preservation With CGF In Orthodontic Treatment Of Reduced Premolars

Objective: To study the clinical effect of site preservation with CGF on orthodontic reduction extraction wound healing,canine movement and prevention of gingival crease.To observe the preservation effect of bone height,bone width and bone mineral density in the extraction area after orthodontic reduction with CGF site alone,to compare the incidence and severity of gingival creases between the two groups during space closure,and to compare the distance of distal movement of maxillary canines,so as to provide sufficient bone mass for orthodontic reduction to close the extraction space and to provide clinical basis for preventing gingival creases.Methods: From October 2019 to December 2020,23 Angle II patients(aged 13 to 30years)with 46 extraction sites were selected from the Stomatology Department of the affiliated Hospital of Youjiang Medical College for Orthodontic treatment.The patients were divided into experimental group and control group: the experimental group(each patient’s right extraction fossa)and the control group(each patient’s left extraction fossa).There were23 extraction sites in each group.All patients were performed maxillary first premolar extraction by the same group of medical staff under aseptic operation.The extraction fossa of the experimental group was treated with CGF,while the control group was treated with routine treatment after tooth extraction to fill the alveolar fossa with fresh blood.2 weeks later,the same group of medical staff were treated with orthodontic straight wire fixation.The height,width and bone mineral density of the local alveolar bone of the maxillary extraction fossa were measured by CBCT and clinical examination records before and 3 months after operation.the distance of canine movement for one month was measured,and the incidence and severity of gingival creases in the two groups during the closure of the space were measured.The statistical method of t-test was used to compare the measurement indexes between the two groups to explore the clinical effect of CGF for site preservation in orthodontic reduction treatment.Results:(1)Bone mineral density of alveolar fossa: According to the measurement data of alveolar fossa area gray value of experimental group and control group 3 months after operation,compared with CBCT image gray value of tooth fossa area extracted 3 months after operation,the results showed that the bone mineral density of experimental group was higher than that of control group(P < 0.001),and the difference was statistically significant.(2)Alveolar ridge height: The difference of alveolar ridge height between the experimental group and the control group was compared before and 3 months after operation.The results showed that the alveolar ridge height of the control group was higher than that of the experimental group(P < 0.001).The difference was statistically significant.(3)Alveolar ridge width: The difference of alveolar ridge width between the experimental group and the control group was compared before operation and 3 months after operation,the results showed that the control group was higher than the experimental group(P < 0.001).The difference was statistically significant.(4)Canine movement distance: According to the measured data of canine distal movement for one month between the experimental group and the control group,the results showed that there was no significant difference between the two groups(P > 0.05).(5)Incidence and severity of gingival creases: The incidence and severity of gingival creases in the experimental group were lower than those in the control group(P <0.01).The results showed that the incidence and severity of gingival creases in the experimental group were lower than those in the control group.Conclusion:(1)CGF can effectively delay the absorption of alveolar bone,increase the bone mineral density of alveolar fossa and maintain the width and height of alveolar ridge.(2)the movement speed of orthodontic teeth in the site preservation area is not significantly different from that in normal alveolar bone.(3)the application of CGF in orthodontic reduction extraction can effectively reduce the occurrence of gingival crease and reduce the severity of gingival crease.