Microleakage Evaluation in Amalgam Restorations Used with Bases

Marginal leakage in amalgam restorations often precedes the development of secondary caries. One potential way to improve the marginal seal of such restorations, and thus minimize the risk of carles development, is to apply a glassionomer base prior to amalgam placement.
This study compared microleakage resistance among amalgam restorations placed with and without light-cured glass-ionomer base materials. Preparations were made in extracted human molar teeth. Four groups were studied, including copal varnish, which was used as a control. All specimens were restored with amalgam. Results indicated significantly greater leakage at the cavity wall/base interface for restorations with a copal varnish cavity liner than for those with a glass-ionomer base. Leakage differences among bases were also found at the amalgam/base interface. Best results were obtained with a dual-cure resin-based system. These samples showed minimal leakage at both the cavity wall/base and the base/amalgam interfaces. These findings suggest that light-cured glass-ionomer bases can be effective in the prevention of microleakage in amalgam restorations.     

大鼠正畸牙齿移动过程中牙周组织超微结构的改变

目的：研究正畸牙齿移动过程中牙周组织超微结构的改变情况。方法：施加外力使大鼠上颌第一磨牙向近中移动后，处死大鼠制备第一磨牙标本，进行透射电镜观察。结果：大鼠受正畸力作用后，组织各种生理、病理反应更加明显，压力侧破骨细胞增多，线粒体、溶酶体增多，高尔基体发达，成纤维细胞排列紊乱、变性、萎缩甚至坏死。张力侧成骨细胞、成纤维细胞的胞浆内高尔基体、内质网丰富，分泌功能旺盛。结论：正畸力引起牙周组织细胞功能的旺盛，改建活跃。     

正畸钢丝冠内固定治疗磨牙纵折的应用

目的:改进磨牙纵折保留治疗的固定方法.方法:对56颗磨牙纵折采用正畸钢丝冠内固定、牙体牙髓治疗加全冠修复的综合治疗,保留患牙.结果:56颗磨牙纵折成功49颗,失败7颗,有效率为87.5%.结论:在磨牙纵折的保留治疗中,正畸钢丝冠内固定是一种较佳的固定方法.     

内眦韧带的应用解剖及组织学研究

目的　研究内眦韧带的分支、走行、附着及其组织学构成。方法　对 6例 12侧尸颅内眦韧带进行解剖观察及测量 ,对 8例 8侧尸颅内眦结构进行组织学切片 ,光镜下观察内眦韧带的纤维构成及内眦区精细构造之间的关系。结果　内眦韧带前支的长度为 7.6± 1.5mm ,最大宽为 4 .5± 0 .7mm ,最小宽为 2 .3± 0 .5mm ;后支长度为 8.0± 1.0mm ,宽度为 6 .4± 1.4mm ;上支长度为 6 .7± 1.5mm ,宽度为 4 .5± 1.1mm ;前支距鼻颌缝的距离为 2 .8±1.0mm ,距鼻额缝的距离为 7.8± 1.5mm ;双侧韧带附着处之间的距离为 13.1± 2 .3mm。结论　内眦韧带由三个分支构成 ,均附着于骨膜。它们主要成分为胶原纤维 ,弹性纤维含量较少。眼轮匝肌内眦区的深层纤维通过组织移行参与构成内眦韧带。     

Effect of finish line variants on marginal accuracy and fracture strength of ceramic optimized polymer/fiber-reinforced composite crowns

STATEMENT OF PROBLEM: Ceramic optimized polymer (Ceromer)/fiber-reinforced composite (FRC) crowns have been promoted as alternatives to conventional crowns. However, little is known regarding the ideal tooth preparation for this type of crown. PURPOSE: This in vitro study evaluated the marginal adaptation and fracture strength of ceromer/FRC crowns with respect to the various types of finish lines. MATERIAL AND METHODS: Four metal dies with different finish lines (0.9-mm chamfer, 1.2-mm chamfer, 1.2-mm rounded shoulder, and 1.2-mm shoulder) were prepared. Forty (10 for each finish line) Targis/Vectris crowns were fabricated on duplicated base metal alloy dies. The restorations were stereoscopically evaluated at 56 points along the entire circumferential margin for measuring the margin adaptation before and after cementation with a resin luting agent. The specimens were then compressively loaded to failure using a universal testing machine. The marginal adaptation (microm) was analyzed with the Kruskal-Wallis test and post-hoc Dunnett test (alpha=.05). The fracture load (N) was analyzed with a 1-way analysis of the variance and the Scheffe adjustment (alpha=.05). The fractured surfaces of the crowns were examined with a scanning electron microscope to determine the mode of fracture. RESULTS: The marginal adaptation of crowns with a shoulder finish line was significantly better than crowns with a chamfer finish line before and after cementation (P<.001). The increased marginal gap after cementation was the lowest in the 1.2-mm rounded shoulder group. The fracture strength of the crowns with the 0.9-mm chamfer and crowns with 1.2-mm chamfer was significantly greater than those of the crowns with the 1.2-mm shoulder or rounded shoulder (P=.011, P=.049, respectively). The mean fracture load of all crowns, regardless of the finish line design, was 1646 N. The fractured surface of the crown revealed adhesive failure and 3 types of cohesive failure (fracture of the Targis and Vectris, Targis fracture with a crack in the Vectris layer, and crushing without fracture). CONCLUSION: The marginal gaps were greater for the chamfer finish line specimens than in the shoulder finish line specimens. However, the fracture strength of the chamfer finish line specimens was greater than that of the shoulder finish line specimens.     

髁突形态与骨性Ⅲ类不同垂直骨面型患者生长发育的相关性

目的:探讨髁突形态与骨性Ⅲ类不同垂直骨面型患者生长发育的关系。方法:采用计算机辅助X线头影测量技术,对不同年龄组骨性Ⅲ类不同垂直骨面型患者的全口曲面断层片进行测量,比较各组间髁突形态特点。结果:高角患者中:升支高度(RH)值在不同年龄段均有显著性差异(P<0.001),成人组>青少年组>儿童组(P<0.05);髁突上部高度(h)值、h/RH值、H/W值在不同年龄组中有显著性差异(P<0.05),且成人组分别大于青少年组和儿童组。均角患者中:h值、RH值均有显著性差异(P<0.001),且成人组分别大于青少年组和儿童组;h/RH值、H/W值在各年龄段间无统计学差异(P>0.05)。低角患者中:h值、RH值在各组中均有显著性差异(P<0.001),且成人组分别大于青少年组和儿童组;h/RH值在各年龄段间无统计学差异(P>0.05);H/W值在不同年龄组间有显著性差异(P<0.01),且儿童组和成人组分别大于青少年组。结论:髁突形态在骨性Ⅲ类不同垂直骨面型患者生长发育过程中存在差异,这可能与他们不同的生长型有关。     

腭裂患者喉塞音的声学特征初探

目的:探讨腭裂患者喉塞音的声学特征。方法:检测存在病理性喉塞音的男性腭裂患儿及正常男性儿童各20名发含口塞音的语句时的语图,观察患者喉塞音声学特征并与正常对照组相比较。结果:腭裂患者喉塞音出现与原塞音的伴随情况不同,可以表现出包括冲直条、嗓音起始时间(VOT)、共振峰转接、冲直条频谱等各种声学指标的异常。结论:塞音的声学特征复杂,应该结合语图形态及各参数的数值共同诊断。     

低强度激光治疗颞下颌关节紊乱病的疗效评价

目的 评估低强度激光(LLLT)疗颞下颌关节痛的效果.方法 将颞下颌关节痛的患者按随机、双盲原则分为激光组(n=21)和对照组(n=21),每位患者均接受连续6d、每天1次的激光或假激光治疗.在治疗前、治疗后、治疗后1月、治疗后2月14个时点对患者的疼痛程度、功能状态进行测量和评估.结果 2组中疼痛视觉模拟评分(VAS...