Objective. The purpose of this study was to examine alterations in blood-flow signals (BFS) from human teeth during an alignment and leveling phase (superelastic wire 0.014′′) in a clinical orthodontic treatment using laser doppler flowmetry (LDF). Materials and Methods. Recordings were made in 12 maxillary left central incisors. The basal value of the BFS from each tooth (without orthodontic forces) was compared with the corresponding values of BFS during four periods of observation: 20 minutes, 48 hours, 72 hours, and one month after the activation of the orthodontic appliance. Results. Statistically significant decrease of BFS was observed at 20 minutes, 48 hours, and 72 hours . No differences were found comparing BFS on day 30 and the corresponding basal values. Conclusion. Under real clinical conditions, a significant decrease in BFS was verified during the initial phase of the treatment, followed by a recovery on day 30. 1. Introduction A common reaction to orthodontic forces is an inflammatory process in the periodontal support tissues. The inflammatory process is a necessary condition for tooth movement and commonly affects the dental pulp [1]. Changes in blood flow are closely related to inflammatory processes. Thus, the evaluation of changes in the blood flow in the dental pulp and periodontal tissues during the application of orthodontic forces is of interest to study the mechanisms of the movement and related iatrogenic alterations in the dental pulp and root [1–4]. In initial studies, alterations in blood flow were analyzed in animal models by invasive and destructive methods due to the difficulties in accessing the pulp and periodontal tissues. More recently, the laser Doppler flowmetry (LDF) has been used to study practically all human organs. The method is noninvasive, offers no risk and allows measurement in real time. The blood-flow signals (BFS) from intact teeth, measured by the LDF, contain information of alterations in the blood flow in the dental pulp. Therefore, the technique has been used to evaluate alterations in blood flow in the dental pulp during orthodontic movements in humans. The information in the literature is limited to experimental movements such as intrusive (intermittent forces) [5–8], extrusive (intermittent forces) [5], intrusive (continuous forces during six days) [8], and tipping (continuous forces during three days) ones [9]. In these studies, experiments were carried out in laboratory, and the movements were monitored during short time intervals. BFS changes in real clinical time and conditions remain
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