Abstract
Objective: To compare three-dimensional tooth movements resulting from relatively higher and lower stresses in a split-mouth design. Materials and Methods: Eight volunteers whose maxillary first premolars were removed for orthodontic treatment participated. Each subject's maxillary canines were retracted by randomly assigned constant stresses of 78 kPa and 4 kPa via segmental mechanics. Dental casts depicting 8-10 visits per subject over 84 days and a three-axis microscope were used to measure movements serially. Descriptive statistics and mixed linear modeling were applied for data analyses (α = .05). Results: Teeth moved by 78 kPa had significantly faster (P = .0005) distal movement (0.066 ± 0.020 mm/day) compared to teeth moved by 4 kPa (0.031 ± 0.012 mm/day). Lateral movement and distopalatal rotation were also significantly faster (fourfold and 10-fold, respectively) with higher than with lower stress (P < .0001). Average extrusion-intrusion, crown torque, and tip were small (≤ |0.25| mm, |2.29|°, and |1.98|°, respectively), fluctuated, and not significantly different between high and low stresses. No lag phase of tooth movement was evident. Conclusions: Maxillary canines were retracted faster by 78 kPa than by 4 kPa. Controlled translation was possible with 4 kPa, but 78 kPa outstripped appliance constraints, causing distopalatal rotation.
Original language | English (US) |
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Pages (from-to) | 102-108 |
Number of pages | 7 |
Journal | Angle Orthodontist |
Volume | 84 |
Issue number | 1 |
DOIs | |
State | Published - Jan 2014 |
Externally published | Yes |
Keywords
- Human
- Mechanical stress
- Mechanics
- Tooth movement
ASJC Scopus subject areas
- Orthodontics