玻璃离子与光固化树脂封闭剂封闭乳牙窝沟

背景：传统方法玻璃离子作为封闭剂耐磨性能差,抗折强度低,位于合面的封闭剂很容易脱落,很难取代树脂封闭剂。 目的：观察光固化树脂封闭剂和非创伤性充填技术玻璃离子窝沟封闭幼儿乳牙的效果。 方法：按同人半口随机比较的方法,对89名3岁幼儿的左或右半口符合窝沟封闭条件的乳磨牙在非创伤性充填技术下行玻璃离子窝沟封闭,对侧半口符合窝沟封闭条件的乳磨牙进行树脂封闭。 结果与结论：窝沟封闭后6,18个月玻璃离子组封闭物脱落率均低于树脂材料组(P < 0.05)。玻璃离子材料最易脱落的牙位是下颌第二乳磨牙;树脂材料最易脱落的牙位是上颌第二乳磨牙。封闭后6个月,玻璃离子组封闭的乳牙患龋率低于树脂材料组,18个月时两组间差异无显著性意义。说明非创伤性充填技术玻璃离子窝沟封闭幼儿乳牙的脱落率低,操作简单,防龋效果肯定,且成本低,在经济学上可行性优于树脂封闭。     

窝沟封闭术预防窝沟龋齿102例的临床疗效分析

目的：探讨分析窝沟封闭术预防窝沟龋的临床效果。方法选取102例6~8岁儿童的下颌第一恒磨牙为研究对象,左右侧进行自身对比分析,治疗组102例儿童下颌左侧第一恒磨牙共102颗牙采取窝沟封闭术的治疗方法,对照组对侧同名牙不涂布窝沟封闭剂,比较两组龋病发生率。结果3年后治疗组患龋率为5.3%,对照组患龋率为24.13%,3年内龋齿发生率治疗组低于对照组,两组比较,差异有统计学意义(P<0.05)。结论对6~8岁儿童的牙齿行窝沟封闭术,对预防儿童窝沟龋的效果显著,值得临床广泛推广使用。     

窝沟封闭技术在预防儿童龋病中的临床应用

目的：分析研究窝沟封闭技术对预防小二龋病的临床应用价值。方法抽取7~9岁学龄儿童1053例,要求四颗第一恒磨牙全部萌出,没有龋齿,首先对牙齿表面进行彻底清洁,隔湿,用37%的磷酸凝胶酸蚀,酸蚀时间为30 s,以后采用清水彻底冲洗配合吸唾管吸唾。隔湿和吹干牙齿表面,采取小毛刷吧封闭剂均匀涂抹在干燥的牙齿表面,要使封闭剂充分渗入窝沟点隙中不能留有气泡。涂封闭剂时间要在1 min以内完成。采取光固化灯照射牙齿,时间为30 s。临床手术以后对窝沟封闭的具体效果、封闭剂凝固以及附着情况给予详细检查。手术以后1~2年复诊。结果经过1~2年的临床复诊检查,在4205颗牙齿当中,400颗牙齿的封闭剂保存完整,没有龋齿,占总体的83.3%。封闭剂脱落的牙齿一共有52颗,当中41颗没有发生龋坏,出现龋坏的牙齿一共有11颗,采取备洞以后永久性充填。结论预防儿童龋齿采取窝沟封闭手术可以起到明显的临床效果,使儿童健康生活质量得到保障。具有临床推广价值。     

流动纳米树脂预防性窝沟龋充填

背景：预防性树脂充填术由于不采用传统的预防性扩展,只去除少量的龋坏组织后即用复合树脂或玻璃离子材料充填龋洞,而未患龋的窝沟使用封闭剂保护。 目的：通过应用美国3M公司生产的Filtek Z350流动纳米树脂对窝沟可疑龋、初龋磨除后进行预防性充填,观察并评价其临床效果,探索预防性充填治疗早期窝沟龋的新方法。 方法：对196例6~25岁患者磨牙的牙合 面窝沟龋在去除龋坏的牙体组织后,采用Eadper prompt自酸蚀粘结技术,用Filtek Z350流动纳米树脂对整个牙面进行预防性充填术,并采用对侧同名牙或邻牙也有窝沟龋者用同一公司生产的ClinproTM可见光固化变色窝沟封闭剂充填作对照研究。 结果与结论：随治4年后发现该方法涂膜保留率高,能有效阻止龋病的进一步发展。实验组与对照组在术后1,2年时的涂膜保留率差异无显著性意义,而在第3,4年时差异有显著性意义(P < 0.01、P < 0.05)。龋病发生率在1,2年时差异无显著性意义,而在3,4年时差异有显著性意义(P < 0.05)。提示Filtek Z350流动纳米树脂预防性窝沟充填是一种有效阻止窝沟早期龋进一步发展的方法。     

Filtek Z350流动纳米树脂与Fuji Ⅸ玻璃离子应用于磨牙窝沟浅龋的效果比较

目的 比较3M ESPE Fihek Z350 Flowable纳米流动树脂(Filtek Z350流动纳米树脂)与而至富士Ⅸ GP玻璃离子水门汀(Fuji Ⅸ玻璃离子)应用于磨牙窝沟浅龋的临床效果,探讨更适合于预防和治疗磨牙窝沟浅龋的方法.方法 选择201例患者的356颗窝沟浅龋的患牙作为研究对象,随机分为两组,实验组101例患者178颗患牙,对照组100例患者178颗患牙,在彻底去除龋坏组织后,实验组用Fihek Z350流动纳米树脂充填龋坏部位并对未龋损的窝沟区域进行预防性充填封闭,对照组采用FUjiⅨ玻璃离子材料进行充填及封闭,观察两种材料4年中的保留情况和继发龋发生率.结果 术后第2～4年Filtek Z350流动纳米树脂的涂膜保留率高于对照组(P＜0.05),两组的继发龋发生率在第1、第2年均为0,在第3、第4年两组间无统计学差异(P＞0.05).结论 Filtek Z350流动纳米树脂是一种能有效预防和治疗磨牙窝沟龋的新方法,建议临床推广使用.     

两种颌间牵引对下颌骨微种植体及周围影响的三维有限元分析

背景：有限元分析能够模拟正畸治疗方法,并对模型进行生物力学分析,此方法被认为是一种重要的、新的正畸生物力学分析方法。 目的：以三维有限元方法分析下颌骨微种植体及周围牙齿在颌间Ⅱ类、Ⅲ类牵引状况下的应力分布。   方法：选择一个牙列完整(无第三磨牙),咬合关系正常,后牙中性颌,无任何颞下颌关节紊乱症状和体征及病变的成年女性志愿者,24岁。采用螺旋CT对志愿者行闭口位头颅CT断层扫描,应用Ansys多种软件结合的方法,建立颞下颌关节、下颌骨及下颌牙列、微种植体的三维有限元模型,模拟临床颌间Ⅱ类、Ⅲ类牵引对微种植体及周围牙齿应力的影响,并对其进行分析。根据方向分别加载,力值为1 N。 结果与结论：①所建三维有限元模型具有较好的几何相似性。②颌间Ⅱ类牵引：种植钉在上颌在尖牙和第一前磨牙之间,下颌在第二前磨牙和第一磨牙之间。第一磨牙应力分布大于第二前磨牙,但第二前磨牙牙周膜应力分布大于第一磨牙牙周膜。③颌间Ⅲ类牵引：种植钉在上颌在第二前磨牙和第一磨牙之间,下颌在尖牙和第一前磨牙之间。下颌尖牙及其牙周膜应力分布大于下颌第一前磨牙。④微种植体及周围牙齿在进行颌间牵引时应力分布变化微小。     

比格犬下颌骨微种植体的置入部位和方法*

背景：比格犬下颌骨解剖结构复杂,微种植体置入位置不恰当会造成微种植体周骨量不足和微种植体松脱。 目的：观察比格犬下颌骨相应解剖结构及微种植体的置入部位和方法。 方法：取成年雄性比格犬尸体下颌骨,测量下颌第二双尖牙牙尖至下颌第一磨牙远中颊尖的长度;下颌第二、三、四双尖牙和第一磨牙根分叉度及牙根分叉处距离下颌神经管的垂直高度;于牙槽嵴下4,6 mm处用游标卡尺测量下颌第二、三、四双尖牙和第一磨牙颊舌向牙槽嵴厚度和近远中根的水平距离。 结果与结论：下颌第二双尖牙牙尖至下颌第一磨牙远中颊尖的长度平均为52.70 mm;距离下颌神经管的垂直高度最远的是第一磨牙,最近的是第四双尖牙,根分叉度最大的是第一磨牙,最小的是第四双尖牙。下颌第二、三、四双尖牙和第一磨牙的颊舌向骨质厚度随着距离牙槽嵴顶深度的增加而增加。在距离牙槽嵴顶4,6 mm的深度,下颌第二、三、四双尖牙和第一磨牙近远中根的水平距离均大于5 mm,且随着距离牙槽嵴深度的增加而增加。说明比格犬下颌第二双尖牙至第一磨牙牙槽骨段骨质结构均匀。在距离牙槽嵴顶4~6 mm深度,单颗牙自身近远中牙根之间足以提供微种植体置入所需骨量。     

国人上、下颌牙槽弓的探讨

将198个颅骨及243个下颌骨(性别未作鉴定)分为不同年龄的四组:2～5岁者(仅有5对乳牙槽);6～12岁者(已出现第一恒磨牙槽);12～17岁者(已出现第二恒磨牙槽)及18岁以上者(已出现第三磨牙槽,除去老年)。对上、下颌牙槽弓进行了测量、分析,得出以下初步结果: 1.国人牙槽弓的指数在成人分别为:上颌:118.2,下颌:77.6。 2.两内侧门牙间正中点至犬牙前外侧缘最突出点间之距离,分别为左:19.6毫米,右:19.8毫米(上颌);左:13.8毫米,右:14.0毫米(下颌)。 3.犬齿前外侧缘最突出点至第二恒磨牙槽外缘最突出点间之距离分别为:左:32.7毫米,右:32.7毫米(上颌);犬牙牙槽前外缘最突出点至第三磨牙牙槽外缘最突出点之距离:左:43.7毫米,右:44.5毫米(下颌)。 4.成人牙槽弓的辐辏距离(Convergence distance)和辐辏角(Convergence angle)分别为42.9毫米,43.1度(上颌);26.4毫米,51.1度(下颌)。 5.上、下颌牙槽弓在不同年龄组均呈现大多数不对称性;尤以上颌为甚,占82.2％《成人);下颌者为67.0％(成人)。     

Auto-CAD计算机辅助设计软件定点测量上颌窦底的位置变化

背景：有学者专门就曲面断层片下颌骨的研究测量方法进行了详尽阐述,随生长发育上颌窦底相对鼻中隔与硬腭交点的相对位置变化尚未见相关报道。 目的：测量4~14岁儿童生长发育过程中上颌窦底的位置变化。 方法：选择乌鲁木齐市口腔医院就诊的300例4~14岁儿童,将收录的人群按Hellman’s牙齿发育阶段分为5组,ⅡA组：完全的乳牙阶段;ⅡC组：第一恒牙萌出阶段;ⅢA组：乳切牙到恒切牙的过渡阶段;ⅢB组：乳后牙(包括尖牙到磨牙)到恒后牙(包括尖牙到第二前磨牙)的过渡阶段;ⅢC组：第二恒磨牙的萌出阶段。通过Auto-CAD计算机辅助设计软件对全颌曲面断层片进行画图分析,定鼻中隔与硬腭的交点为O点,硬腭与上颌窦近中面的交点为PA点,将两点连成一线定位X轴,过O点并与X轴垂直的为Y轴,此时O点为(0,0)点,对上颌窦最低点(S)进行定点,此点会有一个精确的坐标值即(SX,SY),将数据进行统计分析。 结果与结论：ⅡA组与其他各组SX点相比,差异均有显著性意义(P < 0.01);ⅡC,ⅢA,ⅢC组之间无显著性差异(P> 0.05);ⅢB组与ⅢC组之间差异有显著性意义(P < 0.01)。SY点除ⅡA组与ⅡC组之间无差异外(P > 0.05),其余各组之间差异均有显著性意义(P < 0.01)。上颌窦底是向外向下,向内下侧的方向生长。     

无托槽隐形矫治器压低上颌伸长第一磨牙的有限元分析

背景：对于骨质密度不同的成年患者,在运用隐形矫治器压低上颌伸长磨牙时,正畸医师多由主观经验选择膜片厚度,有限元分析有望为不同骨质密度患者选择合适厚度的膜片提供理论依据。目的：通过有限元法分析膜片厚度及骨质密度对成年患者运用隐形矫治技术压低上颌伸长磨牙的影响。方法：基于4种骨密度类型(骨松质Ⅰ类、Ⅱ类、Ⅲ类、Ⅳ类)建立4组有限元模型,并分别与膜片厚度为0.5,0.75,1 mm的3种隐形矫治器模型进行组装,运用Ansys 2021软件进行有限元分析,各组模拟隐形矫治器对上颌第一磨牙施加0.2 mm压低位移,比较各组第一磨牙及其邻牙牙根、牙周膜、牙槽骨的等效应力与牙体位移趋势。结果与结论：(1)各组第一磨牙的等效应力分布情况相同,主要分布于根分叉处;第二前磨牙的等效应力分布于近中颈1/3;第二磨牙的等效应力分布于两颊根根分叉处。(2)第一磨牙及邻牙均产生近中、压低位移趋势;第一磨牙产生颊侧位移趋势,邻牙产生腭侧位移趋势。Ⅱ类骨密度下,第一磨牙X、Y轴位移量最小,Z轴位移量最大;邻牙位移量随骨密度降低而增加。Z轴方向上,第一磨牙及邻牙位移量与膜片厚度呈正比;X、Y轴方向上,第二前磨牙膜片厚度...     

Evaluation of growth hormone axis and responsiveness to growth stimulation of short children with osteogenesis imperfecta

We present four individuals with Gerodermia Osteodysplastica in a Jewish family from Morocco confirming the autosomal recessive inheritance of the disorder. Three previously unreported findings are described: (a) enlarged funnel-shaped mandibular lingula; (b) extension of the mandibular premolar and molar roots below the inferior dental canal, and of the second molars into the lower border of mandibular cortical bone; and (c) hypercementosis of the maxillary incisors and mandibular molars surrounded by a radiolucent halo in several teeth. The facial deformity resulting from maxillary hypoplasia and mandibular prognathism was corrected by orthognathic surgery: Le Fort I maxillary osteotomy and vertical mandibular osteotomy. © 1993 Wiley-Liss, Inc.     

Root Canal Morphology of Chalcolithic and Early Bronze Age Human Populations of El Mirador Cave (Sierra de Atapuerca,Spain)

This study provides a morphological characterization of the inner anatomy of the root canals of permanent first and second molars in Chalcolithic and early Bronze Age human fossils using cone‐beam computed tomography. The general evolutionary trend in present‐day human dentition is related to morphological simplification. As little is known about when this trend appeared in Homo sapiens populations, the aim of this work is to test the presence of modern radicular morphology 4,400 years ago. Fifty‐four permanent first and second maxillary and mandibular molars of 17 individuals were included in the study. All maxillary first and second molars showed three separate roots. Almost all the lower molars analyzed (100% of first molars and 75% of second molars) had two separate roots. More differences in the canal system configuration were documented in the maxillary mesiobuccal roots than in the palatal or distobuccal roots. The most variable tooth in root and canal configuration is the maxillary second molar. It should be pointed out that 12.5% of the teeth analyzed showed a C‐shaped root configuration. Anat Rec, 297:2342–2348, 2014. © 2014 Wiley Periodicals, Inc.     

Evaluation of the relationship between the maxillary posterior teeth and the sinus floor using cone-beam computed tomography

Aim

The aim of this study was to evaluate the relationship between each root of maxillary premolars and molars and the maxillary sinus floor according to sex, sinus position, and age by decade in a Turkish population by using cone-beam computed tomography (CBCT) scanning.

Methodology

We evaluated a database of 5,166 (2,680 maxillary premolars and 2,486 maxillary molars) CBCT scans obtained from 849 patients. The vertical relationship between each root of the molar and premolar teeth to the sinus floor was classified into three types: type 1, the roots penetrated into the sinus floor; type 2, the roots contacted the sinus floor; and type 3, the roots extended below the sinus floor.

Results

The results of the classification of each root in relationship to the sinus floor were as follows: type 3 occurred most frequently in the first (92.4 %) and second (71.6 %) premolar teeth, type 1 (34.2 %) occurred most frequently in the palatinal roots of the first molar teeth, type 3 occurred most frequently in the mesiobuccal (39.9 %) and distobuccal (39.7 %) roots of the first molar teeth, and type 2 (36.7 %) occurred most frequently in the mesiobuccal roots of the second molar teeth. No significant differences were found between the left and right sides, but several differences were found between males and females. The relationship between the posterior teeth and the sinus floor differed according to the age decade interval (p < 0.05).

Conclusions

The maxillary first premolars have no relationship with the maxillary sinus floor, but the maxillary second molars are closer to the sinus floor. Also the second decade and males were most susceptible to undesirable results.     

Morphodigital study of bone quality in the mandibular angle in patients with third molar impacted

The aim of this study was to analyze if the presence of impacted third molars, and their positions in the mandibular angle, can change the bone quality in this area, considering the measure of the cortical thickness in this region as representative or not for mandible fracture risk. Software was used to analyze 50 digital images from panoramic radiographs of patients who had one or two impacted third molars in the mandible, and 30 digital images of patients with agenesis of the mandibular third molar. The thickness of the cortical region of the mandible was measured; it was possible to draw a parallel line to the posterior portion of the mandible and a parallel line to the body of this bone on each side of the image. At the intersection of these lines near the distal portion of the second molar, another line was set up to serve as reference in the cortical thickness measurement. It could be concluded that the cortical thickness of the mandibular angle in male patients without impacted third molars was greater than the thickness in patients with these teeth, and no difference in thickness was found for the female group.     

Emergence of permanent teeth among the meiteis of Manipur,India

To estimate the time and sequence of emergence of the first 28 permanent teeth in rural Meiteis of Manipur, 440 children 5–14 years of age were examined. Median tooth emergence times were earlier in females than males. The first molar was highly variable in its emergence time in both sexes. With the exception of premolars, mandibular teeth emerged earlier than maxillary teeth. Although no definite pattern was found in bilateral differences, left maxillary teeth and right mandibular teeth emerged slightly earlier in females and males, respectively. There was no clear sex difference in the sequence of permanent tooth emergence. The quiescent period between the first and second phases of tooth emergence was more apparent in the mandible than in the maxilla and occurred between the lateral incisor and first premolar in both jaws and sexes. The Meiteis displayed earlier emergence compared to other populations within India. The findings of this study support earlier reports that socioeconomic conditions do not significantly influence permanent tooth emergence; the chief controlling factor is most likely genetic. © 1994 Wiley-Liss, Inc.     

Osteogenesis imperfecta type I with unusual dental abnormalities

A large kindred with dominantly inherited osteogenesis imperfecta was evaluated. Affected individuals had bone fractures, blue sclerae, and hearing loss. In addition, all had dental abnormalities distinct from those previously described in other families with this syndrome. Deciduous teeth were normal in color or blue-grey. On radiographs of an early developing deciduous dentition, pulps were larger than normal. In patients with mixed dentitions, pulp chambers of deciduous teeth were partially obliterated. Increased constriction at the junctions of the crowns and roots was found in some deciduous teeth. One patient had large pulp stones in the pulp chambers of all maxillary deciduous molars. Permanent teeth were normal in color but had oval pulp chambers with apical extensions into the coronal portions of the roots, large coronal pulp stones, narrow root canals, and thin roots. Individuals in this family who did not have osteogenesis imperfecta had normal teeth. In addition, a well circumscribed radiolucency without a sclerotic periphery, involving the apices of all permanent mandibular incisors, was found in the anterior mandible in one patient. These findings support the hypothesis that this family has yet another type I osteogenesis imperfecta "syndrome".     

Remineralization of human natural caries and artificial caries-like lesions with an experimental whisker-reinforced ART composite

This paper compares the remineralization of human natural caries and artificial caries-like dentin lesions treated with a novel whisker-reinforced experimental composite resin (ART composite) with a resin-modified glass ionomer cement (RM-GIC) as control. Ten molars with moderate natural dentin caries were prepared (N). Artificial caries-like dentin lesions were prepared in occlusal dentin of 10 caries-free molars and demineralized at pH 4.3 for 48 h (A). The cavities were restored with ART composite or RM-GIC. All restored teeth were sliced into 120 μm sections. Transverse microradiography combined with digital image analysis was performed to analyze the change in mineral density at the same position in the specimens before and after 4 and 8 weeks remineralization/demineralization treatment. The mean percent remineralization ± standard deviation after 4 and 8 weeks are: N with ART composite, 27 ± 9 and 46 ± 14, respectively; N with RM-GIC, 18 ± 6 and 36 ± 11, respectively; A with ART composite, 48 ± 9 and 66 ± 11, respectively; A with RM-GIC, 50 ± 13 and 62 ± 11, respectively. There was a significant difference between the ART composite and RM-GIC for the remineralization of natural caries (P<0.05). For both restoratives there were significant differences between the remineralization of natural and artificial caries (P<0.001). The ART composite and RM-GIC remineralized natural and artificial caries differently, most likely due to differences in the microstructure and composition of the caries dentin.     

FiltekTM Z 350纳米流动树脂微创修复细小窝沟龋

背景：传统的细小窝沟龋修复需要按Ⅰ类洞形进行预备,对牙体组织破坏较多。 目的：评价流动纳米树脂微创修复细小窝沟龋的临床效果。 方法：选择14~30岁磨牙有窝沟龋且对侧同名牙或邻牙也有窝沟龋患者167例,在一侧磨牙牙合面窝沟龋去除龋坏牙体组织后,采用Adper Single Bond 2全酸蚀黏结技术,用Filtek ^TM Z350流动纳米树脂充填整个微创窝洞作为实验组,对侧同名牙或邻牙窝沟龋用同一公司生产的Filtek ^TM Z350纳米树脂充填作对照。 结果与结论：随访2年后发现实验组Z350流动纳米树脂填充体保留率高,边缘完整性好,边缘着色率低,树脂保留率、边缘完整性及边缘着色率高于对照组(P < 0.05)。提示Filtek ^TM Z350流动纳米树脂微创窝沟充填可有效修复细小窝沟龋。