上颌和下颌基骨长度与完全性 II 类错颌患者牙列拥挤的关系。
Relationship between maxillary and mandibular base lengths and dental crowding in patients with complete Class II malocclusions.
机构信息
Department of Orthodontics, University of São Paulo, Bauru, Brazil.
出版信息
Angle Orthod. 2011 Mar;81(2):217-21. doi: 10.2319/062110-338.1.
OBJECTIVE
To verify the relationship between maxillary and mandibular effective lengths and dental crowding in patients with Class II malocclusions.
MATERIALS AND METHODS
The sample comprised 80 orthodontic patients with complete Class II malocclusions in the permanent dentition (47 male, 33 female) who were divided into two groups according to the amount of mandibular tooth-arch size discrepancy. The maxillary and mandibular effective lengths (Co-A and Co-Gn) and tooth-arch size discrepancies were measured on the initial cephalograms and dental casts, respectively. Intergroup comparisons of apical base lengths were performed with independent t-tests. Correlation between base length and dental crowding was examined by means of Pearson's correlation coefficient (P < .05).
RESULTS
Patients with Class II malocclusion and moderate to severe crowding had significantly smaller maxillary and mandibular effective lengths than subjects with the same malocclusion and slight mandibular crowding. A weak inverse correlation was also found between maxillary and mandibular effective lengths and the severity of dental crowding.
CONCLUSION
Decreased maxillary and mandibular effective lengths constitute an important factor associated with dental crowding in patients with complete Class II malocclusion.
目的
验证上颌和下颌有效长度与安氏Ⅱ类错（牙合）患者牙列拥挤的关系。
材料与方法
本研究共纳入 80 名恒牙完全性安氏Ⅱ类错（牙合）患者（男 47 名，女 33 名），根据下颌牙弓与颌骨不调程度分为两组。在初始头颅侧位片和石膏模型上分别测量上颌和下颌有效长度（Co-A 和 Co-Gn）以及牙弓与颌骨不调程度。采用独立 t 检验对根尖基长进行组间比较。采用 Pearson 相关系数（P<0.05）分析基长与牙列拥挤的相关性。
结果
与安氏Ⅱ类错（牙合）且轻度下颌拥挤的患者相比，中度至重度拥挤患者的上颌和下颌有效长度明显更小。上颌和下颌有效长度与牙列拥挤的严重程度之间也存在弱负相关。
结论
上颌和下颌有效长度的减小是完全性安氏Ⅱ类错（牙合）患者牙列拥挤的一个重要相关因素。
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