Submucosal injection of platelet rich plasma for orthodontic treatment in dentoalveolar protrusion

Maxillary/mandibular dentoalveolar protrusion is one of the most common oral deformities, & orthodontic anterior retraction-intrusion is one of the non-surgical treatment modalities. Our previous research projects revealed that (1) the alveolar bone density in situ is a factor determining the rate of orthodontic tooth alignment within individual & it is the baseline bone metabolism dominates over the alveolar bone density in determining the rate of orthodontic tooth alignment among individuals, (2) submucosal injection of platelet rich plasma (PRP) increases alveolar bone metabolism & accelerates rate of orthodontic tooth alignment, & (3) bone resorption dominates deposition resulting in alveolar bone loss in the anterior alveolus during orthodontic anterior retraction-intrusion. Although the factors affecting rate of orthodontic tooth alignment has been revealed in our previous study, the factors affecting the rate of orthodontic anterior retraction-intrusion, and the methods to decrease loss of alveolar bone after orthodontic anterior retraction-intrusion have not been well studies yet. Based on the above, for the orthodontic treatment of dentoalveolar protrusion, we hypothesize (1) the baseline bone metabolism, dental root volume of anterior teeth, & bone density in situ of anterior alveolus are the factors determining the rate of orthodontic anterior retraction-intrusion; (2) the baseline bone metabolism, dental root volume of posterior teeth, & bone density in situ of posterior alveoli are the factors determining the amount of anchorage loss [mesial movement of posterior teeth]; (3) submucosal injection of PRP in the anterior alveolus increases the rate of orthodontic anterior retraction-intrusion & decrease loss of alveolar bone in the anterior alveolus. Study design & method: We plan to collect 50 patients with bimaxillary dentoalveolar protrusion in 3 years. They will be randomly assigned into 2 groups, the group-1 (N=25) will receive extraction of maxillary & mandibular first premolars and orthodontic anterior retraction- intrusion, & the group-2 (N=25) will receive the same as the group-1 in addition to two times of submucosal PRP injection in the anterior teeth at the beginning of orthodontic treatment & 6 months after the beginning of orthodontic treatment respectively. Serum alkaline phosphatase (ALP) and C-terminal telopeptide of type I collagen (ICTP) will be taken before the orthodontic treatment (T1), and cone beam CT (CBCT) will be taken at T1 and the end of treatment (T2). The serum ALP and ICTP are studied for the osteoblastic and osteoclastic activities in baseline bone metabolism, and the CBCTs for the dental root volume of the anterior and posterior teeth, alveolar bone volume of the anterior alveoli, alveolar bone density in situ of the posterior & anterior teeth, amount of orthodontic anterior retraction-intrusion, and amount of anchorage loss. The data will be statistically analyzed for (1) the correlation of the rate of orthodontic anterior retraction-intrusion to the baseline bone metabolism, dental root volume of anterior teeth, & bone density in situ of anterior alveolus; (2) the correlation of the anchorage loss to the baseline bone metabolism, dental root volume of posterior teeth, & bone density in situ of the posterior alveoli; (3) comparison of the intergroup differences in rate of orthodontic anterior retraction-intrusion and amount of alveolar bone loss in the anterior alveoli. Expecting results: We are expecting the results will fulfill the hypotheses, and from which we would be able to develop a better orthodontic approach toward the treatment of dentoalveolar protrusion that has shorter treatment time, less anchorage loss, and minimal loss of alveolar bone in the anterior alveolus.

Project ID:PG10201-0100
External Project ID:NHRI-EX102-10250EI