Moin Kambiz, Bishara Samir E
Department of Orthodontics, Harvard School of Dental Medicine, Boston, MA, USA.
Angle Orthod. 2007 Jan;77(1):57-63. doi: 10.2319/120405-423R.1.
To evaluate the short-term effects of the buccal shield modification of the lip-bumper design and on various mandibular dental arch parameters and to determine whether the changes in arch widths are due to the tipping or bodily movements of the teeth involved.
This study included 45 consecutively treated patients (29 girls and 16 boys) from a private orthodontic practice. Student's and paired t-tests were used to test the null hypothesis of no change over time for the various measurements. Linear regression analyses were used to determine whether treatment time was a significant predictor of arch width expansion. Significance for all statistical tests was predetermined at P < or = .05.
Student's t-test results indicated the presence of a significant (P < .0001) increase in all the arch parameters measured. The greatest mean expansion was observed at the first (5.0 +/- 2.2 mm) and second (3.4 +/- 2.2 mm) premolar width measurements. The changes in arch width parameters were significantly (P < .0001) greater than the normal age-related changes in the corresponding parameters. There was no significant difference between arch width expansion of the occlusal vs gingival levels, indicating a bodily and not tipping movement. Only 30% of the lower incisors demonstrated an increase in their proclination beyond normal values.
When using the buccal shield appliance, the mandibular arch width parameters can be expanded in the mixed dentition with bodily movement of teeth. The expanded arch width dimensions are greater than what would be expected as a result of normal growth.
评估唇挡设计的颊屏改良对下颌牙弓各项参数的短期影响，并确定牙弓宽度的变化是由于相关牙齿的倾斜移动还是整体移动所致。
本研究纳入了一家私立正畸诊所连续治疗的45例患者（29名女孩和16名男孩）。采用学生t检验和配对t检验来检验各项测量值随时间无变化的零假设。使用线性回归分析来确定治疗时间是否是牙弓宽度扩展的显著预测因素。所有统计检验的显著性预先设定为P≤0.05。
学生t检验结果表明，所有测量的牙弓参数均有显著增加（P<0.0001）。在第一前磨牙（5.0±2.2mm）和第二前磨牙宽度测量中观察到最大的平均扩展量。牙弓宽度参数的变化显著大于相应参数的正常年龄相关变化（P<0.0001）。咬合面与牙龈水平的牙弓宽度扩展之间无显著差异，表明是整体移动而非倾斜移动。只有30%的下切牙倾斜度增加超过正常值。
使用颊屏矫治器时，在混合牙列期，下颌牙弓宽度参数可通过牙齿的整体移动得以扩展。扩展后的牙弓宽度尺寸大于正常生长预期的尺寸。
