替牙列早期上颌慢速扩弓对上颌中段牙及牙槽嵴的影响

Efficacy of early maxillary slow expansion in mixed dentition on maxillary teeth and alveolar crest in the central segment

目的:研究替牙列早期患儿使用上颌慢速扩弓(slow maxillary expansion,SME)对上颌中段恒前磨牙牙胚、乳磨牙及牙槽嵴的影响。方法:根据纳入、排除标准,选择上颌骨横向发育不足行SME治疗的患儿17例,平均年龄(7.41±0.80)岁。治疗前后均基于锥形束CT(CBCT)并使用Dolphin Imaging软件对上颌前磨牙牙胚位置、上颌乳磨牙位置、上颌中段牙弓及牙槽嵴形态进行矫治疗效分析。采用SPSS 21.0软件包对结果进行统计学分析。结果:扩弓后,上颌第一、二前磨牙牙胚未见明显的相对于上颌牙槽骨骨皮质的颊舌向移动及倾斜变化(P>0.05)。扩弓后,上颌中段牙槽嵴顶有明显扩弓效果(P<0.05);在上颌第二乳磨牙段的牙槽嵴底有扩弓效果(P<0.05),而在上颌第一乳磨牙段的牙槽嵴底治疗前后无统计学差异。扩弓后,上颌第一及第二乳磨牙颊尖间宽度增加(P<0.05),且无相对于牙槽嵴的倾斜(P>0.05)。结论:替牙列早期使用SME扩弓对前磨牙牙胚于牙槽骨内的位置无影响。SME能扩宽及颊倾上颌中段牙槽嵴及牙弓,其牙性扩弓及颊倾的效应大于骨性扩弓及颊倾的效应。替牙列早期SME中,牙位越靠近第一磨牙,其扩弓的骨性效应越大。SME是临床早期扩弓矫治的有效手段。

PURPOSE:To study the effect of slow maxillary expansion(SME)appliance on the development of premolar tooth germ,primary molar and alveolar crest in the central segment of maxilla in the mixed dentition.METHODS:According to the inclusion and exclusion criteria,17 children(average age 7.41±0.80 years old)with maxillary transverse deficiency were selected for SME.Before and after treatment,based on cone-beam CT(CBCT)and Dolphin Imaging software,the position of maxillary premolar tooth germ,the position of maxillary primary molar,the shape of maxillary alveolar crest in the central segment were analyzed.SPSS 21.0 software package was used for data analysis.RESULTS:There was no significant change in the buccal-lingual movement and inclination of the tooth germs of the maxillary first and second premolars relative to the maxillary alveolar bone cortex after expansion(P>0.05).After expansion,the maxillary alveolar crest in the central segment had an obvious expansion effect(P<0.05).There was an arch expansion effect in the alveolar crest bottom of the maxillary second primary molar(P<0.05),but there was no significant difference in the alveolar crest bottom of the maxillary first primary molar before and after treatment.Buccal cusp width of maxillary first and second primary molars increased after arch expansion(P<0.05)without inclination of alveolar crest(P>0.05).CONCLUSIONS:SME in the mixed dentition did not affect the position of premolar tooth germ in alveolar bone.SME can expand and buccally tilt central alveolar crest and dental arch,and buccal inclination is greater than that of skeletal expansion and buccal inclination.The closer tooth site is to the first molar,the greater the skeletal effect of arch expansion is at this site.SME is an effective treatment for early maxillary expansion in the clinic.