Third order tooth movements with straight wire appliances. Influence of vestibular tooth crown morphology in the vertical plane

摘要: 1. The labial surface in the vertical plane was investigated 3 sections: center, mesial, and distal edge of an ideally positioned bracket. material consisted 28 casts taken from 14 female male individuals with a mean age 26.8 years. 2. After trimming each cast, resulting photocopied, enlarged 8 times, then digitized under 2.0 mm grid (corresponding to 0.25 original size). 3. Using statistical computer program, curves including standard deviations non-linear regression were calculated individual data. In accordance their anatomy groups teeth formed jaw: front teeth, premolars, molars. curves, comparison squared provide accurate mathematical description tooth crown above-stated sections. 4. angle differentials between reference tangent 20 other tangents calculated. From practical standpoint, information is obtained on extent which torque would be changed if bracket vertically (in 0.5 increments) its ideal position. These changes fluctuate average 1.3 degrees (mandibular teeth) 3.3 molars) for every deviation. 5. comparisons permitted construction bases filling-at least dimension-the most accurately "optimal"