Esthetic restorations of maxillary anterior teeth with orthodontic treatment and porcelain laminate veneers: a case report

If orthodontists and restorative dentists establish the interdisciplinary approach to esthetic dentistry, the esthetic and functional outcome of their combined efforts will be greatly enhanced. This article describes satisfying esthetic results obtained by the distribution of space for restoration by orthodontic treatment and porcelain laminate veneers in uneven space between maxillary anterior teeth. It is proposed that the use of orthodontic treatment for re-distribution of the space and the use of porcelain laminate veneers to alter crown anatomy provide maximum esthetic and functional correction for patients with irregular interdental spacing.     

上颌中切牙不同厚度瓷贴面应力分布的三维有限元分析

目的 采用三维有限元分析上颌中切牙不同厚度瓷贴面应力分布情况。方法在上中切牙三维数据模型上，采用pro-engineer生成不同厚度切端包绕型瓷贴面模型，pro-mechanica软件进行三维有限元分析在不同加载条件下瓷贴面应力分布情况。结果在三种不同加载方式下，不同厚度瓷贴面应力分布无统计差异。结论瓷贴面厚度对其载荷后应力分布影响较小。     

下前牙瓷贴面修复三维有限元模型的建立

目的：建立下颌中切牙及其瓷贴面粘接修复的三维有限元模型,为前牙瓷贴面修复的生物力学分析奠定基础。方法：用Micro-CT扫描离体牙,Mi mi cs软件读取断层影像数据、数据分割、三维重建,Geo-magic软件精修,再运用Catia软件预备牙体并制作瓷贴面及粘接剂层,ANSYS workbench软件网格划分,最后进行有效性验证。结果：准确地建立含有瓷贴面、粘接剂、牙釉质、牙本质、髓腔的下颌中切牙三维有限元模型,网格划分后共计771788个单元,551587个节点。经收敛试验验证所得模型在力学和几何学方面与实体组织具有高度的相似性。应力云图可见Von-Mises应力主要集中于舌侧牙颈及唇侧肩台部,应力峰值发生在肩台偏近中处。结论：应用Micro-CT扫描结合逆向工程软件Mimics、Geomagic,及造型软件Catia,有限元分析软件ANSYS workbench建模的方法快捷可行、准确度高。     

上颌中切牙不同厚度Empress瓷贴面的破坏力学分析

目的:研究不同厚度瓷贴面的破坏过程,探讨提高贴面复合体强度的方法.方法:经软件建模工具生成上颌中切牙矢状面解剖外形.选用临床常用的4种设计外型:开窗型、对接型、包饶型和贴面冠型,结合3种贴面厚度0.5mm,1.0mm和1.5mm,建立12种模型.应用RFPA系统软件处理程序对模型进行处理.比较不同厚度的瓷贴面复合体在负...     

上颌中切牙瓷贴面力学特性的正交实验

目的:通过对上颌中切牙瓷贴面的力学特性进行正交实验研究,得出相对合理的瓷贴面设计方案。方法:制作开窗型、对接型、包绕型厚度分别为0.5、0.7、0.9 mm的中切牙瓷贴面复合体,进行正交力学实验研究。结果:加载部位对应力的影响较大,其次是瓷贴面厚度、加载角度,切端设计类型的影响最小;当加载角度为0°、厚度为0.9 mm、加载部位为中1/3时对应力影响最小。结论:正常覆的患者为瓷贴面修复的最佳适应证;瓷贴面厚度对瓷贴面应力分布的影响较大,而瓷贴面切端设计对应力的影响最小。     

热压铸造陶瓷制作前牙瓷贴面的临床效果观察

目的:探讨采用热压铸造瓷块制作前牙瓷贴面的临床修复效果.方法:选择要求进行前牙修复的患者32例,共206颗牙.其中,氟斑牙患者20例,轻度四环素牙患者8例,牙唇侧釉质发育不全或釉质表面有明显裂纹患者4例.根据邻牙颜色、皮肤和唇颜色选择瓷块颜色,进行失蜡热压铸造成型,并经过口内试戴、仔细修形后,再在超薄贴面的边缘嵴、切缘等部位进行特殊艺术化染色处理,采用VariolinkⅡ树脂粘固剂黏结超薄瓷贴面.结果:根据改进的USPHS标准评价临床美学修复效果:瓷贴面的半透性极佳,边缘完整性好,与预备体边缘终止线对接密合.经7年多使用,瓷贴面边缘无着色,且能吸收牙龈和邻牙的色泽而产生良好的变色龙作用,同时精雕后的瓷面能够产生自然牙釉质的表面特征.经7年多临床观察,206个瓷贴面仅有5个发生瓷体折裂和脱落.结论:采用热压铸造陶瓷制作瓷贴面,具有操作简单、修复体强度高、磨除牙体组织少、美观效果好等特点,特别适用于氟斑牙、轻度四环素牙、自然磨损牙的美学修复.     

Cerinate瓷贴面在牙齿美容修复中的临床应用

目的：通过对58例患者382颗瓷贴面修复效果的临床观察,评价该技术在牙科美容中的作用.方法：门诊选择382颗需要美容修复的前牙和前磨牙,使用Cerinate瓷贴面修复系统进行修复,于修复后1周、6个月、1年、2年、3年和5年复诊,对患者满意度、贴面脱落、折裂、边缘适合性、修复体颜色及牙龈健康情况等进行评价.结果：临床调查结果显示,1年内100%的瓷贴面具有良好的边缘适合性及牙龈健康状况,修复体色泽稳定,有2个修复体折裂重新制作,3个脱落并再行粘结,1颗牙出现加重的敏感症状而行根管治疗术.所有患者对修复效果均非常满意.结论：Cerinate瓷贴面修复系统是一种可靠的、理想的前牙美容修复方法.     

正交试验法的上颌中切牙瓷贴面力学特性的有限元分析

目的综合上颌中切牙瓷贴面受力的主要因素,设计正交试验对其力学特性进行有限元分析,得出相对合理的瓷贴面设计方案。方法制作开窗型、对接型、包绕型厚度分别为0.5、0.7、0.9㎜的中切牙瓷贴面复合体,螺旋CT扫描后建立有限元模型,基于正交试验进行有限元分析,得出最佳应力分布条件下各因素参数的最优组合。结果加载部位对应力的影响最大,其次为瓷贴面厚度、加载角度,切端设计类型最小;当加载角度为0°、厚度为0.9㎜、加载部位为中1/3时对应力影响最小;开窗型、对接型瓷贴面的各部位的应力均大于包绕型,且于牙颈部存在较大应力集中区。结论正常覆牙合的患者为瓷贴面修复的最佳适应证;瓷贴面厚度对应力分布的影响较大;瓷贴面切端设计对应力的影响最不重要,但临床上尽可能选择包绕型设计;牙唇倾度对瓷贴面应力分布的影响较小,沿牙体长轴传导的力最有利。     

Effect of provisional restorations on the final bond strengths of porcelain laminate veneers

The purpose of this in vitro study was to evaluate the effect of the different provisional restorations cementation techniques on the final bond strengths of porcelain laminate veneers (PLVs). Thirty-six extracted human central incisors were sectioned 2 mm below the cemento-enamel junction, and crown parts were embedded into self-cure acrylic resin. Standardized PLV preparations were carried out on labial surfaces of the teeth. Then the teeth were randomly divided into three groups of 12 each. In group 1, provisional restorations were cemented with eugenol-free cement. In group 2, prepared teeth surfaces were first coated with a desensitizing agent then provisional restorations were cemented with resin cement. In group 3, provisional restorations were not fabricated to serve as control. After specimens were stored in distilled water for 2 weeks, provisional restorations were removed and final IPS Empress 2 ceramic veneers were bonded with a dual-curing resin. Two microtensile samples from each tooth measuring 1.2 x 1.2 x 5 mm were prepared. These sections were subjected to microtensile testing and failure values were recorded. The data were analysed by one-way anova and Tukey HSD tests. The PLVs, placed on the tooth surface that had received a dentine desensitizer and provisional restorations luted with resin cement (group 2), showed the lowest bond strength in all test groups. But no statistically significant differences were found between the bond strength of PLVs in control group (no provisional restorations) and group 1 (provisional restorations cemented with eugenol-free cement before final cementations). Scanning electron microscopic (SEM) examination of this study also showed that the bonding to enamel surface was better in control group and group 1 than group 2.     

Treatment of a transmigrated and an impacted mandibular canine along with missing maxillary central incisor: A case report

IntroductionTreatment of a case with impacted canines is complex and numerous options are available ranging from disimpaction to forced eruption.ObjectiveThe objective of this case report was to describe the treatment of a 19-year-old male, with a skeletal Class II, dental Class II Division 1 malocclusion, prognathic maxilla, proclined maxillary incisors, with missing left maxillary central incisor and bilateral mandibular canine impaction.MethodologyThe orthodontic treatment plan included forced eruption of the impacted canines and conversion of maxillary left lateral incisor to central incisor.ConclusionProper diagnosis and implementation of orthodontic biomechanics can minimize the amount of prosthetic and surgical intervention needed in the management of transmigrated canine and smile designing.     

纤维桩修复上颌中切牙的三维有限元研究

目的应用三维有限元法研究上颌中切牙采用全瓷冠修复和纤维桩全瓷冠修复时牙本质的应力变化情况,分析纤维桩修复对上颌中切牙应力大小和分布的影响。方法通过螺旋CT扫描、Mimics软件、ANSYS软件建立不同牙体量上颌中切牙的三维有限元模型,分别行全瓷冠修复和纤维桩全瓷冠修复,模拟咬合加载,记录牙本质的von Mises应力和最大拉应力。结果相同牙体量的上颌中切牙,采用纤维桩全瓷冠修复时牙本质的应力值小于全瓷冠修复时的应力值,应力分布基本相似。结论纤维桩的应用能降低上颌中切牙牙体组织的应力峰值,有利于降低牙折的风险,并且不改变原有应力分布模式。     

Influence of tooth preparation design on the stress distribution in maxillary central incisors restored by means of alumina porcelain veneers: A 3D-finite element analysis

AIM: The present study aimed at providing 3D-FEA engineering tools for the understanding of the influence of tooth preparation design on the stress distribution and localization of critical sites in maxillary central incisors restored by means of alumina porcelain veneers under functional loading. METHODS: A 3D-FEM model of a maxillary central incisor is presented. An arbitrary chewing static force of 10 N was applied with an angulation of 60 and 125 degrees to the tooth longitudinal axis at the palatal surface of the crown. The model was considered to be restored by means of alumina porcelain veneers with different tooth preparation designs. The differences in occlusal load transfer ability of the two restorative systems are discussed. RESULTS: The maximum Von Mises equivalent stress values were observed in the window restorative system for both 125 and 60 degrees load angulations. When the chamfer with palatal overlap preparation was simulated, the stress distributed uniformly in the cement layer, whereas in the window preparation the stress mainly occurred in the incisal area of the cement layer. SIGNIFICANCE: When restoring a tooth by means of porcelain veneers, the chamfer with palatal overlap preparation better restores the natural stress distribution under load than the window technique.     

In vitro evaluation of the fracture resistance and microleakage of porcelain laminate veneers bonded to teeth with composite fillings after cyclic loading

PURPOSE

There is insufficient data regarding the durability of porcelain laminate veneers bonded to existing composite fillings. The aim of the present study was to evaluate the fracture resistance and microleakage of porcelain laminate veneers bonded to teeth with existing composite fillings.

MATERIALS AND METHODS

Thirty maxillary central incisors were divided into three groups (for each group, n=10): intact teeth (NP), teeth with class III composite fillings (C3) and teeth with class IV cavities (C4). Porcelain laminate veneers were made using IPS-Empress ceramic and bonded with Panavia F2 resin cement. The microleakage of all of the specimens was tested before and after cyclic loading (1 × 10⁶ cycles, 1.2 Hz). The fracture resistance values (N) were measured using a universal testing machine, and the mode of failure was also examined. The statistical analyses were performed using one-way ANOVA and Tukey post hoc tests (α=.05).

RESULTS

There was a significant difference in the mean microleakage of group C4 compared with group NT (P=.013). There was no significant difference in the fracture loads among the groups.

CONCLUSION

The microleakage and failure loads of porcelain laminate veneers bonded to intact teeth and teeth with standard class III composite fillings were not significantly different.     

切牙管及其与上颌中切牙位置关系的研究进展

上颌中切牙的矢状向位置决定了正畸患者的侧貌美观,在正畸临床诊疗中,上颌前突患者一般需要通过减数四个前磨牙进行矫治,以最大支抗内收上下颌前牙,来改善侧貌,解决突度问题。传统支抗正畸手段可以使上颌中切牙内收5.78mm,而种植支抗可以使上颌中切牙的最大内收量增大至8mm,但是在上颌前牙内收的过程中,少数上颌中切牙会侵犯上颌骨一个重要的解剖结构——切牙管,从而导致牙根吸收,牙齿松动等并发症的出现。因此本文就切牙管及其与上颌中切牙位置关系的研究进展做一综述。     

瓷贴面与纳米树脂修复上前牙切角缺损的对比研究

目的：比较瓷贴面和纳米树脂修复上前牙切角缺损的临床疗效。方法：对上前牙切角缺损患者行瓷贴面修复或纳米树脂修复,1年后对其修复效果进行评估。结果：瓷贴面在修复体颜色、边缘密合度、牙髓反应方面,均优于纳米树脂修复。结论：瓷贴面用于上前牙切角缺损的修复可取得比较好的临床效果。     

上颌埋伏阻生中切牙的临床研究

目的统计温州医学院附属口腔医院正畸科门诊病例中上颌埋伏阻生中切牙的患病率、唇腭侧的比例及治疗情况。方法选取2005年1月至2008年1月期间,在温州医学院附属口腔医院正畸科就诊的错殆患者中,所有在放射科拍摄过螺旋CT的上颌中切牙埋伏阻生的患者。统计其发病、治疗情况。结果2005年1月至2008年1月期间,在温州医学院附属口腔医院正畸科共有8763名患者,上颌中切牙埋伏阻生者共103名。男性50名,女性53名。唇侧阻生71名（其中3名为双侧阻生）,腭侧阻生20名,垂直阻生12名。其中76颗埋伏牙采用外科手术结合正畸牵引治疗,27颗采取外科拔除,3颗采用减阻助萌术。结论在温州医学院附属口腔医院正畸门诊患者中上颌中切牙埋伏阻生约占1．18％,男女比例基本一致,唇侧阻生最常见,上颌埋伏阻生中切牙的治疗以外科手术结合正畸治疗为主。     

倒置埋伏阻生上颌中切牙的临床矫治效果研究

目的 探讨倒置埋伏阻生上颌中切牙的矫治时机和矫治方法.方法 选择10例患者共10颗上颌单侧倒置埋伏阻生中切牙为研究对象.矫治前常规拍摄全口曲面断层片、CT片,确定倒置埋伏牙的冠根形态及其与邻牙的关系.根据埋伏牙的翻转角度选择面弓式前方牵引器或主弓丝牵引.牵引结束测试牙髓活力.结果 通过7～14个月牵引,倒置埋伏阻生的上颌中切牙基本达到牙列的正常位置;埋伏牙牙髓活力测试结果为25.9±2.8,对侧同名牙为25.0±3.3,差异无统计学意义(t=1.15,P=0.159).结论 倒置埋伏阻生的上颌中切牙并非一定需要拔除,选择恰当的时机对倒置埋伏阻生的上颌中切牙给予有效的外科-正畸联合治疗,效果较好.     

Solitary median maxillary central incisor in association with Goldenhar's syndrome: a case report

Goldenhar's syndrome is a rare disorder characterized by several anomalies that include dermal epibulbar cysts, auricular appendices and malformations and vertebral anomalies. In this article, the authors report a case of Goldenhar's syndrome in a 10-year-old child who presented with the classical signs of this condition and a solitary median maxillary central incisor (SMMCI).     

上中切牙全瓷冠修复后牙本质的三维有限元分析

目的：研究上颌中切牙进行全瓷冠修复后牙本质的应力分布情况。方法：应用三维有限元法进行分析,模拟在最大咬合力120N时,分别以与牙体长轴成30°、40°、45°和50°角加载的情况下,4种不同全瓷冠材料IPS EmpressⅡ,In-Cream Alumina,In-Cream Zirconia,Vita MarkⅡ修复上颌中切牙后牙本质的应力分布。结果：应用不同全瓷冠材料修复后,牙本质上的应力分布相似,但加载力角度的增加会使张应力改变很大。结论：进行上颌中切牙全瓷冠修复时,需要注意修复后上下颌中切牙的角度,否则可能会造成牙本质的损伤。     

上颌中切牙与尖牙同时阻生的临床特征分析

目的分析上颌中切牙与同侧尖牙同时阻生病例的临床特征。方法选择上颌中切牙与同侧尖牙同时阻生病例21例,分析上颌中切牙阻生类型与尖牙阻生情况,测量阻生侧及对侧侧切牙发育或萌出异常情况。结果与中切牙阻生同时发生的尖牙76.2%为唇侧阻生,其中完全易位与不完全易位占唇侧阻生尖牙的68.8%,尖牙唇侧阻生病例中侧切牙根远中倾斜和伴牙冠近中倾斜者占87.5%,尖牙唇侧或腭侧阻生病例中,出现锥形或过小等畸形侧切牙的比例分别为31.25%和40.00%。上颌中切牙与尖牙不同阻生类型患者,前牙反牙合比例都超过40%,且多为牙型反牙合。结论与中切牙阻生同时发生的尖牙阻生多为唇侧阻生,与中切牙阻生类型无关,与侧切牙根远中倾斜高度相关,尖牙完全易位与过小或锥形等畸形侧切牙有关。