安氏Ⅱ1类下颌后缩颞下颌关节结构与垂直骨面型、覆(牙合)覆盖的相关性研究

目的:探讨安氏Ⅱ1类下颌后缩颞下颌关节结构与垂直骨面型及咬合因素是否存在相关性.方法:30例安氏Ⅱ1类下颌后缩儿童(男14例,女16例),平均年龄(10.8±1.1)岁(8.1～13.0岁),分别进行TMJ的MRI扫描检查,X线头影测鼍和覆(牙合)覆盖的模型测量,并采用pearson榆验髁突位置和盘突关系与垂直骨而型和咬合因素的相父分析.结果:下颌平面角与前间隙有弱的正相关;前后而高比与所有测量项目均无相关性;后而高与代表盘突关系的Dp-Cc/Cs-Cc角有弱的正相关关系;前而高与Dp-Cc/Cs-Cc、Ca-Ca'、Ca-Cp值角均有弱的负相关关系;髁突位置与覆(牙合)覆盖均无关;盘突关系与覆(牙合)无关,但覆盖与Ca-Dm、Dp-Cc/Cs.Cc呈正相关,相关系数为0.420、0.460.结论:垂直骨而型与髁突后移、盘前移有一定的相关性.覆(牙合)、覆盖与髁突位置无关;而覆盖越大者,盘前移位越明显,盘突关系越具有病理性.     

Influence of fiber-reinforced composites on the resistance to fracture of vertically fractured and reattached fragments

Introduction

The aim of this in vitro study was to evaluate the fracture type and test the effects of 2 different fibers on fracture strength of roots with reattached fragments. The null hypothesis was that adding suitable fibers to the content of dual-cure adhesive resin cement increases the fracture resistance of reattached fragments under vertical forces.

Methods

Root canals of 45 teeth were prepared, and the teeth were intentionally fractured into 2 separate fragments. Control groups (n = 7 each) consisted of unfractured teeth with instrumented and obturated or only instrumented root canals. The fractured teeth were divided into 3 groups (n = 15 each), and separated fragments were reattached by using (1) dual-cured resin cement (Clearfil SA), (2) dual-cured resin cement + polyethylene fiber (Construct), or (3) dual-cured resin cement + glass fiber (Stick-Net). Force was applied at a constant speed of 0.5 mm/min to the root until fracture. Mean load was recorded and analyzed statistically by using Kruskal-Wallis and Dunn tests (P = .05). Fracture types were analyzed by using χ² analysis with Yates correction.

Results

Stick-Net demonstrated the lowest fracture resistance (P < .05), whereas Construct and Clearfil SA had similar fracture strengths (P > .05). The roots in the control group showed the highest fracture resistance. However, there was no statistically significant difference between the Construct, Clearfil SA, and control groups (P > .05).

Conclusions

Separated fragments of vertically fractured teeth can be reattached by using a dual-cured resin or by adding polyethylene fiber (Construct).     

Prolonged bleeding following tongue piercing: a case report and review of complications

The number of adolescents and young adults undergoing intraoral piercing is increasing in the United States. Numerous articles have documented complications following intraoral piercing. This article presents a case of prolonged bleeding and reviews other documented sequelae following intraoral piercing. The article may serve as a guide to dental professionals whose patients seek advice regarding these procedures.     

窝洞内内毒素对牙髓组织LPS结合受体TLR4表达的影响研究

目的 动物实验观察窝洞内内毒素对牙髓组织LPS结合受体TLR4表达的影响,探讨牙髓组织在LPS刺激后的信号转导途径.方法 在8头小型猪磨牙和前磨牙上制备不同深度窝洞,窝洞分为牙釉质深层组、牙本质浅层组、牙本质深层组.封入一定量的内毒素,分另q于术后3天、7天、14天、28天处死动物取牙.采用免疫组织化学染色的方法,观察小型猪磨牙和前磨牙窝洞内封入内毒素后牙髓组织中TLR4的表达和分布.结果 小型猪正常牙髓中未见TLR4阳性细胞.内毒素实验组随着窝洞深度增加,TLR4阳性细胞数增加.在深窝洞组3a窝洞下方牙髓组织中TLR4阳性细胞多为中性粒细胞表达,其他实验组多为单核细胞表达.结论 牙髓组织中TLR4的表达提示内毒素通过牙本质渗透至牙髓,通过LPS信号受体TLR4在牙髓组织的炎症发展过程中发挥作用.     

氟离子缓释正畸粘接剂缓释性能的研究

目的全面了解树脂型氟离子缓释正畸粘接剂(fluoride releasing adhesive，FRA)缓释氟离子的性能，建立一套评价FRA氟离子缓释性能的测试方法及指标。方法测定并计算FRA在一定时间中累计氟离子释放量，绘制出时间—氟离子累计释放量趋势线，并计算每单位质量FRA有效氟离子释放量。结果时间—氟离子累计释放量趋势线显示，FRA在90d内能持续、稳定地释放氟离子，每单位质量FRA在90d内有效氟离子释放量为449μg/g。结论本实验FRA试样具有稳定缓释氟离子的能力。     

Tissue oxygen tension and blood-flow changes in rat incisor pulp with graded systemic hyperoxia

The role of oxygen in the regulation of the pulpal microcirculation is unknown. This investigation is aimed to measure tissue oxygen tension and blood-flow changes in the pulp of rat lower incisors during graded systemic hyperoxia, and to determine the response of the pulpal vasculature to various oxygen tensions. Twenty-four Sprague-Dawley rats were anaesthetized and artificially ventilated with the appropriate gas mixture. Recessed oxygen-sensitive microelectrodes were used to measure pulpal tissue oxygen tension via a small access cavity filled with saline on the labial surface of the incisor. A laser Doppler flowmeter was used to record pulpal blood-flow. Inspired oxygen was increased stepwise from 20 to 100% in 20% steps. Systemic blood-gas concentrations were measured at each step. Systemic arterial oxygen tension at 100% oxygen ventilation reached 481.2 +/- 30.7% of the baseline at 20% oxygen breathing (n=21). Pulpal tissue oxygen tension did not change significantly whereas pulpal blood-flow fell dose-dependently to 74.6 +/- 5.0% at 100% oxygen ventilation (n=21). Systemic hyperoxia, therefore, induces a significant reduction in pulpal blood-flow whereas pulpal tissue oxygen tension remains relatively stable, indicating an oxygen-dependent local regulatory mechanism.     

咀嚼肌表面电极肌电图重复性检验和参考值的建立

目的:对成年人咀嚼肌表面电极采集的肌电信号加以分析,研究下颌在6种不同运动状态下咀嚼肌肌电信号的可重复性,并取得正常参考值。方法:30名22-44岁受试者进行咀嚼肌表面电极肌电图检查,记录下颌姿势位、牙尖交错位和扣齿运动时双侧咬肌、颞肌前束和二腹肌前腹的肌电活动,每个受试者在3个不同时段各测试一次。结果:3次测试的咀嚼肌峰值电位之间无统计学差异(P>0.05)。下颌姿势位时,右侧咬肌峰值电位95%正常参考值为0-0.1,左侧为0-0.13,右侧颞肌前束为0-0.67,左侧颞肌前束为0-0.1,右侧二腹肌前腹为0-0.13,左侧二腹肌前腹为0-0.1;牙尖交错位时,右侧咬肌峰值电位95%正常参考值为0.33-2.53,左侧为0.47-2.5,右侧颞肌前束为0.23-2.23,左侧颞肌前束为0.2-3.67,右侧二腹肌前腹为0.13-1.07,左侧二腹肌前腹为0.1-0.87;扣齿运动时右侧咬肌峰值电位95%正常参考值为0.5-2.5,左侧为0.73-2.3,右侧颞肌前束为0.4-3.47,左侧颞肌前束为0.3-3.63,右侧二腹肌前腹为0.2-1.07,左侧二腹肌前腹为0.13-0.97。结论:表面电极采集的双侧咬肌、颞肌前束和二腹肌前腹的肌电活动具有一定的可重复性。     

Recognition and phagocytosis of multiple periodontopathogenic bacteria by anti-Porphyromonas gingivalis heat-shock protein 60 antisera

The present study has been performed to evaluate Porphyromonas gingivalis heat shock protein (HSP) 60 as a candidate vaccine to protect against multiple putative periodontopathic bacteria. Mouse anti-P. gingivalis HSP antisera demonstrated the elevated IgG antibody titers against the multiple bacteria tested and cross-reacted with heat-induced bacterial proteins of the target bacteria. The antisera also demonstrated a significantly higher opsonophagocytosis function against all the target bacteria than the control sera (P<0.01). We concluded that P. gingivalis HSP 60 could potentially be developed as a vaccine against multiple periodontopathic bacteria.     

Gingival crevice microbiota from Chinese patients with gingivitis or necrotizing ulcerative gingivitis

The objective of this study was to quantitatively compare the bacterial population structure in plaque from the gingival margin of two groups of 21 Chinese patients with gingivitis or necrotizing ulcerative gingivitis (NUG). Subjects were recruited in four dental clinics in Eastern China. Samples were quantitatively assessed by immunofluorescence and fluorescent in situ hybridization for taxa known to be associated with periodontal diseases. The analyses showed that the fusiform taxa (Fusobacterium nucleatum/Fusobacterium periodonticum, Leptotrichia buccalis, Tannerella forsythensis, and Capnocytophaga sp.), Campylobacter rectus, Prevotella intermedia, Prevotella nigrescens, Selenomonas sputigena, and treponemes were present in both groups with high prevalence. Porphyromonas gingivalis and Actinomyces gerencseriae were much more prevalent in the NUG group. Quantitatively, most taxa, including P. gingivalis, F. nucleatum and the treponemes, accounted, on average, for < 3% of the total bacterial cell number. Only P. intermedia/P. nigrescens, P. gingivalis, S. sputigena, A. gerencseriae, and the sum of all monitored suspected periodontal pathogens were significantly increased in the NUG group. The present study demonstrates for both groups a highly diverse plaque composition and suggests that, etiologically, the overall concentration and the concerted effects of the entire group of opportunistic pathogens thriving in NUG-associated plaque are of prime importance.