Pulpal blood flow changes due to rapid maxillary expansion

Abstract

Objective: To determine the pulpal blood flow (PBF) changes in anchorage teeth associated with the high forces of a rapid maxillary expansion (RME) appliance. Materials and Methods: The study was performed with 14 girls and 7 boys for a total of 21 patients between 10 and 15 years of age (mean, 13.1 6 1.39 years). A modified acrylic bonded RME appliance was used as an expansion appliance. Laser Doppler flowmetry was used for the pulpal perfusion measurements. Records were taken from 42 upper central incisors, 28 canines, and 42 first molars at the following time intervals: just before expansion (T1); at the first week of expansion (T2); at the end of the expansion process (T3); and at the third (T4), seventh (T5), and 12th weeks of retention (T6). The data gained were statistically evaluated by parametric tests. Results: PBF values of the anchorage teeth were doubled at the first week of expansion; however, these values began to decrease because of separation of the median palatal suture. PBF values tended to reach their initial values during the retention period. Pulpal perfusion changes of all examined anchorage teeth were similar to each other from the beginning to the end of the evaluation. Conclusion: PBF changes that occur with RME are reversible. (Angle Orthod. 2010;80:1136-1140

Does rapid maxillary expansion induce adverse effects in growing subjects?

“…Application of the inclusion and exclusion criteria and follow-up on the referred studies identified 30 relevant publications (Figure 1). [3][4][5][6][7][8][9][10][11][12][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] Heterogeneity of the results of the investigations with similar technique of maxillary expansion was high (.85%). A meta-analysis was not performed for this reason.…”

“…A meta-analysis was not performed for this reason. Twenty-one studies 3,4,6,8,9,15,[18][19][20][22][23][24][25][26][28][29][30][31][32][33][34] were retrospective, five studies 7,11,12,16,17 were prospective, and four studies 5,10,21,27 were prospective and randomized. Six studies 10,18,[22][23][24]33 compared the results with a control group of the same age, and eight studies 4,6,10,12,22,[32][33][34] analyzed the long-term effects of RME.…”

“…19,33 used other methods, such as probe and intraoral measure of pulpal blood flow. RME was used to treat transverse maxillary deficiency, and the device was maintained in situ as a passive retainer for a minimum of 3 months and a maximum of 18 months.…”

“…Mean age at the start of orthopedic expansion in the evaluated samples ranged from 7 to 17 years. Overall, in 24 studies 3,[4][5][6][7][9][10][11][15][16][17][18][19]21,22,[24][25][26][27][30][31][32][33][34] the sample comprised teenagers; in six studies, 8,12,20,23,28,29 the sample was younger than 10 years (mean age, 8.6 years). The devices applied were bonded with acrylic coverage on the occlusal surface of posterior upper teeth or banded with the 2 or 4 anchored tooth (Hyrax or Haas type maxillary expanders).…”

“…RME was used to treat transverse maxillary deficiency, and the device was maintained in situ as a passive retainer for a minimum of 3 months and a maximum of 18 months. The screw was activated twice a day in 25 studies, [3][4][5][6][7][9][10][11][12]15,17,18,20,21,[24][25][26][27][28][29][30][31][32][33][34] once a day in 1 study, 19 and more than twice a day in 4 studies. 8,16,22,23 All the included studies used a clinical evaluation, such as molar contact or overcorrection of 2-3 mm, to assess the required expansion.…”