A comparative evaluation of different compensating curves in the lingual and labial techniques using 3D FEM.

Because adults dislike the visibility of orthodontic appliances, the use of the lingual orthodontic technique has increased over time. But few studies compare tooth movement of the lingual technique with that of the labial technique. In this study, human mandibular left teeth were aligned, and a 3-dimensional finite element model was made (consisting of 19382 nodes and 12150 elements). To compare the effect of compensating curves on canine retraction between the lingual and the labial orthodontic techniques, the compensating curve was increased on the.016-in stainless steel labial or lingual archwire, and a 150-g force was applied distally on the canine. The relative direction and the amount of tooth displacement of the finite element model were compared on a schematic displacement graph (magnified 10,000 times), and the compressive stress distributed on the root surface was observed. The pattern of tooth movement (with or without a compensating curve) was different between the labial and the lingual techniques. As the amount of compensating curve increased (0, 2, and 4 mm) in the archwire, the rotation and the distal tipping of the canine was reduced. The antitip and antirotation action of compensating curve on the canine retraction was greater in the labial archwire than in the lingual archwire.     

Expression and significance of stromal cell-derived factor-1alpha and its receptor CXCR4 in human dental pulp cells

OBJECTIVE: To investigate the expression of CXCR4 in cultured human dental pulp cells (HDPC) in vitro and the corresponding ligand SDF-1alpha level of HDPC supenatants stimulated by lipopolysaccharide (LPS) and tumor necrosis factor-alpha (TNF-alpha), and to explore the role of SDF-1alpha on the proliferation and the migration of HDPC. METHODS: The expression of CXCR4 in HDPC was detected by immunocytochemistry technique and indirect immunofluorescence technique. The culture supernatants of HDPC were collected after HDPC had been simulated by LPS and TNF-alpha of different concentrations for 48h and then the SDF-1alpha level was assayed by quantitative sandwich ELISA. Meanwhile, the effects of recombinant human SDF-1alpha (rhSDF-1alpha) on the proliferation and the migration of HDPC at different concentrations were observed by MTT and Boyden Chamber Assay. RESULTS: CXCR4 was expressed in cytomembrane of HDPC and SDF-1alpha was secreted into their normal cell supernatants with a concentration of (4513.55 +/- 962.92) ng/L. The secretion of SDF-1alpha was both significantly decreased by stimulation with LPS and TNF-alpha (P < 0.05). In addition, rhSDF-1alpha stimulated the HDPC proliferation at the concentrations of 50, 100, 200 microg/L (P < 0.01) and increased the chemotactic migration of HDPC significantly after 9h's incubation with the concentrations of 50, 100 microg/L (P < 0.05). CONCLUSIONS: SDF-1alpha accelerated the proliferation and the migration of HDPC which expressed CXCR4. SDF-1-CXCR4 axis may play a role in repair of pulp injury.     

味觉出汗综合征的临床分析

为了观察味觉出汗综合征的发病情况,对100例行腮腺区手术的患者,作了客现的碘-淀粉试验检查。结果表明:行浅叶切除术者,其发病率(100％)明显高于包括肿瘤及其周围部分正常腺体的区域切除术者(发病率为18.18％)。放射治疗虽可降低味觉出汗综合征的发病率,但放射治疗后仍有复发可能。     

非血管化游离骨移植中细胞活力的实验研究

目的 :探讨非血管化游离骨块中细胞存活能力及数量与离体时间的关系。方法 :取狗非血管化游离髂骨块 ,在离体 2 5～ 15 0min的不同时间点 ,消化骨块获得细胞 ,进行活细胞计数。对消化获得细胞体外培养2 4h后 ,再进行活细胞计数 ,分析细胞存活与离体时间的关系。结果 :在离体 2 5～ 15 0min时间内 ,骨块细胞的存活率从 91.96%降至 9.5 2 %。统计学检验 ,2 5min组与 70min以前组之间没有统计上的差别 ,P >0 .0 5 ;2 5min组与 70min及其以后组之间有明显差别 ,P <0 .0 1。培养 2 4h后 ,以上各时间点的细胞存活率则从88.73 %到 3 .88% ,组间差别与刚离体时相同 ,但 70min后的各组活细胞率明显下降。结论 :非血管化狗游离髂骨块的离体时间对其中的细胞存活有明显影响 ,离体 70min可能是其关键点 ;在非血管化游离骨移植中 ,尽量缩短骨块的离体时间 ,有利于保存更多的活细胞     

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目的探讨螺旋CT三维重建技术在埋伏尖牙正畸牵引中的应用价值。方法2006年3月至2007年12月,南京大学医学院附属口腔医院正畸科对12例颌骨内尖牙埋伏阻生患者进行螺旋CT检查、颌面骨三维重建,并与曲面断层X线片进行对比观察。结果CT三维重建能对颌骨内埋伏阻生尖牙准确定位,与颌骨内的实际情况所见完全一致,极大的提高了埋伏尖牙正畸牵引的成功率,有效地缩短了患者的治疗时间,减少了患者的痛苦。结论螺旋CT三维重建影像可以直观地显示埋伏阻生尖牙在颌骨内的生长情况,对上颌骨埋伏阻生尖牙的定位、治疗方案的制定具有重要指导作用。     

女性生长发育高峰期后安氏Ⅱ1类错(牙合)后部牙弓与颌骨宽度的分析

目的分析生长发育高峰期后女性安氏Ⅱ1类患者存在的后部牙弓及颌骨宽度不调,为安氏Ⅱ1类患者的早期治疗提供临床依据.方法选取30例生长发育高峰期后的女性安氏Ⅱ1类及35例安氏Ⅰ类患者,在模型上测量上下牙弓的宽度并计算宽度差值(PTID),在头颅后前位X线片上测量上颌宽度、鼻宽度及下颌角间宽度,用独立样本的t检验进行统计学分析.结果生长发育高峰期后的安氏Ⅱ1类患者均存在着上牙弓及上颌骨的狭窄,其PTID与安氏Ⅰ类患者相比具有显著性差异(P<0.05).结论生长发育没有改善安氏Ⅱ1类患者上颌后部牙弓及基骨的狭窄;对于安氏Ⅱ1类患者,早期通过扩大上牙弓的宽度,使下颌自由前伸,有利于Ⅱ类关系的纠正.     

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.     

Er, Cr: YSGG激光与氟化物联合应用对牙体硬组织脱矿的影响

目的：体外研究Er，Cr：YSGG激光与氟化物联合应用对牙体硬组织抗酸性的影响。方法：标本随机分成4组，分别为对照组，激光组，氟处理组，激光＋氟组，进行不同处理后，0．1mol／L乳酸（pH4．8）脱矿24h，原子吸收分光光度计检测脱矿液中溶解的钙离子浓度，能谱分析仪进行氟原子含量分析，扫描电镜观察牙釉质和牙本质表面超微结构的变化。结果：激光组、氟处理组、激光＋氟组溶解的钙离子浓度都明显降低，与对照组有显著性差异（P〈0．05），但是激光＋氟组钙离子浓度仅略低于激光组、氟处理组，与其无显著性差异（P〉0．05）；氟含量的测定仅在氟处理组牙釉质和牙本质标本有氟峰出现；扫描电镜观察见，激光组：表面不平呈鳞片状、峭壁状，无玷污层，釉质结构清晰可见，牙本质小管开放，无熔融、炭化等热损伤的表现；氟化钠组：表面有大量玷污层和碎屑，并可见到许多小颗粒沉积在牙釉质和牙本质表面；激光＋氟组：表面结构与激光组相似，未见颗粒沉积。结论：Er，Cr：YSGG激光与氟化物无联合效应，其机制仍需进一步的研究与探讨。     

Surface alteration of human tooth enamel subjected to acidic and neutral 30% hydrogen peroxide

Objectives

To investigate the effects of acidic and neutral 30% hydrogen peroxide (HP) on human tooth enamel in terms of chemical structure, mechanical property, surface morphology and tooth colour.

Methods

Twenty-seven human dental blocks were obtained from premolars and randomly divided into three groups (n = 9): Group acidic HP (30% HP, pH ≈ 3.6), Group neutral HP (30% HP, pH ≈ 7.0) and Group DW (distilled water, pH ≈ 6.8). Attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), Raman spectroscopy, atomic force microscopy (AFM) investigation, microhardness test and colour measurements were carried out before and after treatments. ATR-FTIR and Raman spectroscopy were analysed and then the carbonate:mineral ratio (C:M), Raman absolute intensity (RAI), Raman relative intensity (RRI), and laser-induced fluorescence intensity (FI) were obtained for evaluation.

Results

The C:M, percentage microhardness and percentage RRI of group acidic HP decreased more significantly than those of group neutral HP (P = 0.02, P = 0.001, P < 0.001, respectively) and group DW (P = 0.01, P = 0.008, P < 0.001, respectively). Whilst group neutral HP and group DW had no statistical difference in above terms (P = 0.818, P = 0.528, P = 0.158, respectively). Significant morphological alterations were observed in group acidic HP. Group acidic HP and neutral HP had no significant difference in percentage FI (P = 0.652) and ΔE (P = 0.906).

Conclusions

This study suggested that neutral 30% HP had the same efficiency in tooth bleaching and it caused less deleterious effects on enamel than acidic 30% HP.     

创伤性面瘫物理疗法的临床研究

目的 比较超短波加离子导入疗法（A组）与电刺激加离子导入疗法（B组）治疗创伤性面瘫的效果。方法 对39例创伤性面神经损伤患者进行临床对照研究，通过量化面神经功能评价、神经电图检查及面神经功能的主观评价比较面神经损伤的治疗效果。结果 创伤性面瘫以青年男性多见，损伤程度以中、重度为主；对于神经损伤轻、中度患者,A组与B组均能促进神经恢复，B组神经功能开始恢复时间早于A组。对于神经损伤重度患者，A组与B组神经恢复率高于对照组，两组均不能减少并发症出现率。结论 超短波加离子导入疗法与电刺激加离子导入疗法均能促进面神经损伤的恢复，但对于减少并发症发生率并无帮助。