Severe skeletal bimaxillary protrusion treated with micro-implants and a self-made four-curvature torquing auxiliary: A case report

BACKGROUNDBimaxillary protrusion is a clinically common dentofacial deformity, particularly among Chinese patients. This kind of malformation can severely affect facial esthetics and, even in mild cases, is difficult to correct without surgery. Unfortunately, many patients abandon treatment because of fear of surgery. Here, we describe a case of severe skeletal bimaxillary protrusion treated with nonsurgical orthodontic treatments, highlighting an alternative treatment option.CASE SUMMARYA 31-year-old woman wished to address a severe protrusion profile (approximately 8 mm overbite) and gummy smile. Cephalometric analysis and superimposition showed a severe skeletal class II pattern with a mandibular retrusion, and proclined and protrusive mandibular incisors. Panoramic radiograph showed a missing mandibular right third molar. A diagnosis of severe bimaxillary dentoalveolar protrusion was made. Taking into account the patient’s fear of orthognathic surgery, she accepted the proposed alternative treatment using micro-implants and a self-made four-curvature torquing auxiliary. The treatment allowed for maximal en masse anterior tooth retraction, proper relocation of incisors, and alleviation of the skeletal class II pattern. Esthetically, the patient’s lip protrusion was significantly decreased as was the overjet (from 10.5 mm to 1.8 mm), and the results remained stable throughout the 2-year follow-up.CONCLUSIONNonsurgical treatment using micro-implants and a four-curvature torquing auxiliary may benefit severe cases of skeletal bimaxillary protrusion in adults.     

自攻型微螺钉种植体正畸支抗的临床应用

目的介绍自攻型微螺钉种植体用于正畸支抗的临床过程,以及支抗对磨牙的控制作用,评价自攻型微螺钉种植体支抗的疗效。方法安氏Ⅱ1错合患者16例,年龄在13～25岁。上颌拔除双侧第一前磨牙,矫治设计上颌强支抗,在矫治器粘结之后植入自攻型微螺钉种植体。应用上颌后牙区自攻型微螺钉种植体作为支抗内收前牙,治疗前、后拍摄头颅定位侧位片,并测量切牙和磨牙的治疗变化。结果16例患者应用自攻型微螺钉种植支抗顺利完成正畸治疗,均建立了正常的前牙覆合覆盖关系,上颌第一磨牙在前、后向和垂直向未发生显著性移动,切牙在前、后向发生显著性移位,患者的上颌凸度明显改善。结论自攻型微螺钉种植体是一种稳固、舒适的支抗系统,达到支抗磨牙的稳定,有效治疗拥挤、前突畸形,该方法广泛用于正畸治疗中。     

正畸用微种植体加载时机的组织学研究现状及进展

近年来,微螺钉支抗成为正畸医师研究的热点,其稳定、有效、不依赖患者配合的优点克服了传统支抗的不足。微螺钉种植体的组织学研究较少,其最佳加载时机仍存在争议。本文就微螺钉种植体加载时机的组织学研究进展做一综述。     

微型种植体支抗与口外弓支抗治疗上牙弓前突的疗效比较

目的通过与口外弓支抗治疗上牙弓前突的疗效比较,评价微型种植体支抗作用效果。方法将20例严重上牙弓前突的患者随机分成两组,种植体支抗组10例,口外弓支抗组10例,分别应用种植体支抗与口外弓支抗配合MBT直丝弓矫治技术关闭拔牙间隙。通过头影测量方法比较两组患者矫治前、后的反映牙、颌、面形态特征的标志点位置变化,并通过成组t检验分析两组牙、颌、面形态变化的差异。结果矫治后在矢状向上,种植体支抗组上中切牙内收（6.56±1.37）mm,上唇突点后移（4.36±0.79）mm,口外弓支抗组上中切牙内收（5.56±0.66）mm,上唇突点后移（3.86±0.73）mm,两组差异均无统计学意义（P〉0.05）;而两组的上第一磨牙近中移动分别为（0.55±1.36）mm、（1.81±0.84）mm,差异有统计学意义（P〈0.05）。在垂直向上,种植体支抗组上中切牙压低（1.96±0.82）mm,上第一磨牙压低（1.59±1.15）mm,口外弓支抗组上中切牙伸长（0.60±0.74）mm,上第一磨牙伸长（0.24±1.72）mm,两组差异均有统计学意义（P〈0.05）。种植体支抗组U1-SN角减小（16.76±2.85）°、口外弓支抗组U1-SN角减小（20.10±2.09）°,两组差异有统计学意义（P〈0.05）。结论微型种植体支抗不仅具备较强的矢状向支抗作用,同时具备有传统口外弓支抗难以实现的垂直向支抗能力,有效压低前牙以利于矫正深覆、露龈笑畸形,压低上磨牙以利于骨性Ⅱ类面型的改善。     

Effect of different sterilization modes on the surface morphology,ion release,and bone reaction of retrieved micro-implants

Objective:To compare as-received and sterilized micro-implants in order to assess the prospects of reusing them.Materials and Methods:Forty micro-implants from a single manufacturing lot were used in the study. Thirty were retrieved from patients after successful service in their mouth and with no signs of failure. The retrieved micro-implants were divided into three groups, according to method of sterilization: autoclave, gamma radiation, or ultraviolet radiation. All groups were subjected to scanning electron microscope analysis for surface morphology assessment. The specimens were immersed in a standard simulated body-fluid solution kept at 37°C in an incubator; the solution was then withdrawn at 24 hours and 30 days to evaluate aluminum and vanadium ion release by atomic absorption spectrophotometer in parts per billion. The micro-implants were then surgically implanted into the tibia of rabbits for a 1-month healing period, and the bone-implant blocks were processed for routine histologic examination.Results:This study revealed that sterilized micro-implants had altered surface topography, different ion release values, and different histologic cell reactions than the as-received micro-implants.Conclusions:Within the limitations of this study, it can be concluded that retrieved self-drilling micro-implants have tip sharpness variations that require correction before insertion by bone drilling. The autoclave-sterilized micro-implants showed better histologic results than micro-implants sterilized by gamma or ultraviolet rays.     

个体化舌侧矫治器微种植体支抗滑动法内收上前牙的三维有限元模型的构建

目的建立包含eBrace托槽、牙、牙周膜、牙槽骨、弓丝和微种植体在内的三维有限元模型,为分析个体化舌侧矫治器上颌腭部不同位置微种植体滑动法关闭上前牙间隙的生物力学特征做准备。方法依据eBrace个体化舌侧矫治器的设计特点,基于CT采集的实际数据,先建立实体模型,再构建含有牙、牙周膜、牙槽骨、托槽、弓丝和微种植体6个成分的个体化舌侧矫治系统的三维有限元模型。结果1．根据微种植体植入位置不同,共建立6个有限元模型,微种植体分别位于上颌第二双尖牙和第一磨牙间、第一磨牙和第二磨牙间距离牙槽嵴顶2mm、6mm和10mm。每个模型包括40个实体模型。2．用10节点四面体单元进行单元剖分,第一个模型（微种植体在上颌第二双尖牙和第一磨牙之间距离牙槽嵴顶2mm）在网格剖分后有节点741670个,单元513925个。其他模型的节点数和单元数类似。结论建立了包含eBrace托槽、牙、牙周膜、牙槽骨、弓丝和微种植体在内的三维有限元模型,该有限元模型构建全面、复杂、真实,几何相似性很强;为下一步分析个体化舌侧矫治器上颌腭部不同位置微种植体滑动法关闭上前牙间隙的生物力学特征奠定了基础。     

正畸微种植体支抗稳定性研究方法现状

近年来,正畸微种植体以其突出的优点广泛应用于错牙合畸形的临床矫治中。为了达到有效的支抗作用,越来越多的学者开始关注正畸微种植体稳定性的研究。本文将从组织学、生物力学以及临床评估3个方面对其研究方法作一综述。