正畸粘结剂添加金属镧对变形链球菌抑制作用的研究

目的明确正畸粘结剂添加金属镧后,对变形链球菌生长的抑制作用,并检测其抑制能力的大小。方法实验分3组,阴性对照组用复合树脂粘结剂（compositeresin）、实验组用含5%氯化镧复合树脂粘结剂、阳性对照组用GCFujiOrtho树脂改良型玻璃离子粘固剂,每组10个样本。分别将3组粘结剂样本放入变形链球菌悬液中,厌氧菌培养48h,酶标仪测量菌悬液OD值。结果 3组样本变链菌液OD均值从大到小依次为复合树脂粘结剂组、含5%氯化镧复合树脂粘结剂组、GCFujiOrtho树脂改良型玻璃离子粘固剂组,其组间两两比较,均有显著性差异（P〈0.01）。结论含5%氯化镧复合树脂粘结剂具有明显的抑制变形链球菌生长的作用。     

14例正畸减数第一恒磨牙病例临床疗效分析及相关问题初探

目的 评价正畸减数第一磨牙的临床疗效,并就减数第一磨牙的相关矫治原则、间隙关闭情况及第三磨牙的建（牙合）等问题进行初步探讨.方法 选取我科近10年完成的14例减数第一磨牙矫治病例进行分析.通过对矫治前后模型的PAR指数和头颅侧位片,对矫治后磨牙间隙关闭、咬合关系及软组织侧貌进行评价;并通过曲面断层片,初步评价第二磨牙的牙根吸收和牙槽骨的改建以及第二磨牙和前磨牙的牙根平行状况.结果 14例患者平均疗程（29.5±4.3）个月,PAR疗效分析显示治疗后变差或无改变0例,改善5例,明显改善9例,提示拔牙间隙关闭满意,牙（牙合）关系良好;软组织侧貌协调,面型满意;曲面断层片显示第二前磨牙与第二磨牙牙根平行状况良好,第二磨牙牙根及牙槽骨无明显吸收.结论 减数第一磨牙病例只要严格把握适应证,合理的支抗设计和严谨的临床操作,可以获得满意的临床矫治效果.     

M-CSF油包水型微乳对大鼠正畸牙齿移动的影响

目的探讨巨噬细胞集落刺激因子（M—CSF）油包水型（W／O）微乳对大鼠正畸牙齿移动及其牙周组织改建的影响。方法选用蓖麻油和无水乙醇分别作为表面活性剂和助表面活性剂,油酸聚乙二醇甘油酯作为油相,M-CSF水溶液为水相,制备成M—CSF油包水型微乳。加力ld开始,每2d将该微乳局部注射于大鼠左上第一磨牙,分别于1d,3d,7d,14d测量上颌第一磨牙移动距离,用HE染色观察牙周组织改建情况。结果加力1d,4组间无明显差异（P〉0．05）;加力3d,M—CSF微乳组正畸牙移动距离大于其它组,但与M—CSF水溶液组差别无统计学意义（P〉0．05）;加力7d和14d,M-CSF微乳组正畸牙移动距离同样大于其它组,差异有统计学意义（P〈0．01）,且压力侧牙槽骨骨吸收陷窝增多,呈“锯齿”状。结论大鼠正畸牙齿局部注射M．CSF油包水型微乳可以促进其移动及压力侧牙周组织改建。     

Comparison of static friction with self-ligating,modified slot design and conventional brackets

Objective

To compare the static frictional forces generated at the bracket/wire interface of stainless steel brackets with different geometries and angulations, combined with orthodontic wires of different diameters.

Material and Methods

The frictional forces were evaluated with three different types of metal brackets: a passive self-ligating (SmartClip^TM, 3M/Unitek, Monrovia, USA), with a modified slot design (Mini Uni Twin^TM, 3M/Unitek, Monrovia, USA) and conventional (Kirium, Abzil, São José do Rio Preto, Brazil). The samples were mounted in a testing device with three different angulations and tested with 0.014" and 0.018" stainless steel wires (American Orthodontics, Sheboygan, USA). The static frictional force was measured using a universal testing machine (DL 500, EMIC^®, São José dos Pinhais, Brazil) with a crosshead speed of 1 mm/min. Statistical analysis was performed by two-way ANOVA followed by Bonferroni''s post hoc test.

Results

There was a significant difference (p<0.05) in static friction when the three types of brackets were tested with the same wire size. The wire diameter influenced friction only when the brackets had a 10º angulation (p<0.05). The angulation influenced friction (p<0.05) when the brackets were associated with a 0.018" wire.

Conclusion

Brackets with a modified slot design showed intermediate static frictional force values between the conventional and self-ligating brackets tested.     

Biological Changes on the Compressing Side of Orthodontic Teeth Stimulating by Soft laser

目的：研究在弱激光作用下接受正畸力作用的牙齿的压力侧出现的生物学变化，为临床应用弱激光加速牙齿移动提供理论依据。方法：实验动物分2组，每组20只。A组动物接受正畸力，B组动物除接受正畸力之外，还接受弱激光照射。采用免疫组化检测层连蛋白的组间表达变化，采用原位杂交检测RANKL(receptor activator of NF-kB ligand)mRNA的组间表达变化。结果：免疫组化结果表明，新生血管活跃的高峰期出现在接受正畸力的第7d。与A组相比，接受弱激光照射的B组呈现层连蛋白的高表达。同样，与A组相比，原位杂交检测发现在接受弱激光照射的B组中，正畸牙压力侧呈现RANKL mRNA的高表达。结论：弱激光照射后能够促进正畸牙压力侧血管新生(呈现层连蛋白高表达)，从而促进破骨细胞的分化激活。此外弱激光还能够促进破骨细胞活化因子RANKL的表达，增强正畸牙压力侧的破骨细胞的活性，加快骨改建。     

SHEAR BOND STRENGTH OF METALLIC BRACKETS PHOTO-ACTIVATED WITH LIGHT-EMITTING DIODE (LED) AT DIFFERENT EXPOSURE TIMES

The purpose of this study was to compare the shear bond strength of orthodontic metallic brackets photo-activated with two different light-curing sources at different exposure times: halogen light (XL 1500, 3M ESPE) and LED light (Ortholux, 3M Unitek). Sixty bovine permanent lower incisors were inserted into PVC tubes containing plaster. The buccal surfaces were cleaned with pumice and water, and then etched with 37% phosphoric acid gel. The XT Primer bonding agent (3M Unitek) was applied to the enamel surfaces and the metallic pre-coated brackets (Transbond APC II system, 3M Unitek) were attached to upper central incisors. The teeth were randomly divided into four groups (n=15). In Group I (Control), halogen light was used for 40 seconds, while in Groups II, III, and IV were light-cured with LED light unit for 40, 10, and 5 seconds, respectively. The teeth were stored in distilled water at 37°C for 24 hours. The brackets were submitted to shear bond strength test in universal testing machine (Instron) at a crosshead speed of 0.5 mm/minute. Shear bond strength means (MPa) were 4.87 for Group I; 5.89 for Group II; 4.83 for Group III, and 4.39 for Group IV. Tukey''s test detected no statistically significant differences among the groups regarding the shear bond strength (p>0.05). Neither of the types of light-curing sources or exposure times influenced the shear bond strength of metallic brackets.     

正畸配合根尖下截骨术治疗严重双牙弓前突的临床研究

目的探讨骨性双牙弓前突患者经正畸正颌联合治疗后,颌面部硬组织、软组织在矢状方向上的变化及其相互关系,为临床矫治方法的选择提供参考。方法临床选择10例安氏Ⅰ类重度骨性双牙弓前突符合正颌手术的患者,术前正畸矫治完成后实施上、下前颌部截骨后退术（术中去除上下第一前磨牙牙骨块）,术后进一步正畸治疗以改善咬合关系。通过手术前后头影测量分析,比较颌面部硬组织,软组织在矢状方向上后退量及其相互关系。结果10例重度骨性双牙弓前突患者,经正畸一正颌联合矫治后,效果非常显著。上颌切牙平均后退7．13mm,上颌牙槽骨平均后退6．48mm,上颌软组织唇突点平均后移5．66nm。上颌硬、软组织后退的比例为1：0．87;下颌切牙平均后退6．62mm,下颌牙槽骨平均后退6．91mm,下颌软组织唇突点平均后移5．89mm。硬软组织后移的比值为1：0．85。结论重度骨性的双牙弓前突患者,应首选正畸正颌联合治疗,可彻底纠正前突的面型,上、下颌的硬软组织显著的内收,达到十分满意的疗效。     

Experimental study of brackets adhesion with a novel enamel-protective material compared with conventional etching

IntroductionA reliable adhesion between fixed devices and dental surfaces is a key factor for the clinical success of any orthodontic treatment. Adhesion preparation is associated with damages related to abrasive cleaning, enamel structure defacing caused by etching, enamel loss when removing resin remnants at orthodontic treatment finishing stage or when conditioning surface for adhesive failure and fractures at bracket removal.AimThe objective of this study was to compare the shear bond strength of metallic brackets to enamel adhered with a novel non-damaging and remineralizing material for enamel versus the traditional 37% phosphoric acid etching.Material and methods75 Premolars collected from 15- to 40-years old healthy donors requiring extraction were collected. The teeth were then randomly divided into three groups (n = 25). One group was used for the experimental new method (EX), the second for the conventional phosphoric acid etching (PA) method and the third group was left without any treatment (NT). The metallic brackets were fixed with Transbond® XT adhesive and composite resin polymerized for 40 s with a halogen photocuring lamp. The shear bond strength was quantified by means of a universal testing machine at 1 mm/min crosshead speed and a load cell of 1 kN.Statistical analysis usedTests of normality, adjustment of the data to a root square, a one-way ANOVA and Tukey tests were performed.ResultsStatistically significant differences between the NT (1.4 MPa), PA (32.1 MPa) and EX (9.7 MPa) groups were observed.ConclusionsThe experimental material for conditioning human enamel induces calcium phosphates crystals on the enamel surface and improves the bond strength in comparison to the NT group.