Thiruvenkatachari Badri, Javidi Hanieh, Griffiths Sarah Elizabeth, Shah Anwar A, Sandler Jonathan
School of Dentistry, University of Manchester, Manchester, United Kingdom.
School of Clinical Dentistry, University of Sheffield, Sheffield, United Kingdom.
Am J Orthod Dentofacial Orthop. 2017 Oct;152(4):509-515. doi: 10.1016/j.ajodo.2017.02.015.
Maxillary canines are generally considered important both cosmetically and functionally. Most claims on the importance of maxillary canines, however, have been based on expert opinions and clinician-based studies. There are no scientific studies in the literature reporting on their cosmetic importance or how laypeople perceive a smile treated by maxillary canine extractions. Our objective was to investigate whether there is any difference in the perceptions of patients' smiles treated by extracting either maxillary canines or first premolars, as judged by orthodontists, dentists, and laypeople.
This retrospective study included 24 participants who had unilateral or bilateral extraction of maxillary permanent canines and fixed appliances in the maxillary and mandibular arches to comprehensively correct the malocclusion, selected from orthodontic patients treated at Chesterfield Royal Hospital NHS trust in the United Kingdom over the last 20 years. The control group of patients had extraction of maxillary first premolars followed by fixed appliances and finished to an extremely high standard judged by the requirement that they had been submitted for the Membership in Orthodontics examination. The finished Peer Assessment Rating scores for this group were less than 5. The end-of-treatment frontal extraoral smiling and frontal intraoral views were presented for both groups. The photographs were blinded for extraction choice and standardized for size and brightness using computer software (Adobe Photoshop CC version 14.0; Adobe Systems, San Jose, Calif). The work file was converted to an editable pdf file and e-mailed to the assessors. The assessor panel consisted of 30 members (10 orthodontists, 10 dentists, and 10 laypeople), who were purposely selected. The measures were rated on a 10-point Likert scale.
The attractiveness ratings were not statistically significantly different between the canine extraction and premolar extraction groups, with a mean difference of 0.33 (SD, 0.29) points. A 1-way repeated-measures analysis of variance to test the difference in scores among the laypeople, orthodontists, and dentists (n = 30) showed no statistically significant difference (Wilks lambda = 0.835; P = 0.138), and the Bonferroni test indicated that no pair-wise difference was statistically significant.
No statistically significant difference was found in the smile attractiveness between canine extraction and premolar extraction patients as assessed by general dentists, laypeople, and orthodontists. Further high-quality studies are required to evaluate the effect of canine extraction and premolar substitution on functional occlusion.
上颌尖牙通常在美观和功能方面都被认为很重要。然而，关于上颌尖牙重要性的大多数说法都基于专家意见和临床医生的研究。文献中没有科学研究报告其在美观方面的重要性，也没有研究外行人如何看待上颌尖牙拔除后的微笑。我们的目的是调查正畸医生、牙医和外行人对上颌尖牙或第一前磨牙拔除治疗的患者微笑的看法是否存在差异。
这项回顾性研究纳入了24名参与者，他们在上颌和下颌牙弓中进行了单侧或双侧上颌恒牙尖牙拔除及固定矫治器治疗，以全面矫正错牙合畸形，这些参与者选自过去20年在英国切斯特菲尔德皇家医院国民保健服务信托基金接受治疗的正畸患者。对照组患者拔除上颌第一前磨牙，然后使用固定矫治器，根据他们已提交正畸专业会员资格考试的要求，治疗达到了极高的标准。该组最终的同伴评估评分低于5分。两组均展示了治疗结束时的正面口外微笑和正面口内视图照片。照片对拔牙选择进行了盲法处理，并使用计算机软件（Adobe Photoshop CC版本14.0；Adobe Systems，加利福尼亚州圣何塞）对尺寸和亮度进行了标准化处理。工作文件被转换为可编辑的pdf文件并通过电子邮件发送给评估人员。评估小组由30名成员组成（10名正畸医生、10名牙医和10名外行人），他们是经过特意挑选的。这些指标在10分的李克特量表上进行评分。
尖牙拔除组和前磨牙拔除组之间的吸引力评分在统计学上没有显著差异，平均差异为0.33（标准差，0.29）分。一项单因素重复测量方差分析用于检验外行人、正畸医生和牙医（n = 30）之间评分的差异，结果显示没有统计学上的显著差异（威尔克斯lambda = 0.835；P = 0.138），邦费罗尼检验表明没有两两之间的差异具有统计学显著性。
普通牙医、外行人及正畸医生评估发现，尖牙拔除患者和前磨牙拔除患者的微笑吸引力没有统计学上的显著差异。需要进一步开展高质量研究来评估尖牙拔除和前磨牙替代对功能咬合的影响。
