2种功能矫治器治疗安氏Ⅱ类1分类错作用机理的比较研究

目的通过X线头影测量分析,比较SanderⅡ和Twin-Block功能矫治器治疗生长发育期安氏Ⅱ类1分类错(Ⅱ1类错)的作用机制。方法随机分为T、S两组,各13例患者,T组采用Twin-Block技术矫治,S组采用SanderⅡ矫治器矫治。全天戴用矫治器治疗4~10个月。测量治疗前、后摄X线头侧位片,测量项目28项,并进行统计学分析。结果两组上颌发育均受抑制,经Pancherz分析,覆盖均显著减小,骨、牙因素没有差别;下颌均有显著生长,S组下颌升支长(Co-Go)比T组增加明显,S组下颌Ar-Go-Me角增加明显;S组的平均矫治时间为5.5个月,T组为7个月。结论2种矫治器均能明显促进下颌骨生长;SanderⅡ比较适合垂直生长型的Ⅱ类患者;SanderⅡ较Twin-Block疗程缩短。     

改良Twin-Block矫治器治疗安氏Ⅱ~2类错的临床观察

目的研究改良Twin-Block矫治器对生长发育期安氏Ⅱ类2分类错的矫治作用。方法选择27例替牙期或恒牙早期安氏Ⅱ类2分类错患者,应用改良Twin-Block矫治器进行矫治,通过测量治疗前后X线头颅定位侧位片,进行统计学分析。结果矫治后磨牙调整为中性关系或轻度近中关系;前牙覆覆盖正常;上下颌关系及软组织侧貌协调。结论改良Twin-Block矫治器治疗早期安氏Ⅱ类2分类错畸形疗效显著,能促进下颌生长,改善下颌后缩。     

反式Twin-Block与Frankel-Ⅲ治疗安氏Ⅲ类错作用机制的比较

目的:通过X线头影测量分析,比较反式Twin-Block和Frankel-Ⅲ功能矫治器治疗生长发育期安氏Ⅲ类错的作用机制.方法:选择替牙期、恒牙早期安氏Ⅲ类错患者20 例(男9 例,女11 例),平均年龄11 岁2 个月,随机分为T、F 2 组,每组各10 例患者,T组采用反式Twin-Block矫治器矫治,F组采用Frankel-Ⅲ矫治器矫治.全天戴用矫治器治疗4~11 个月.分别对治疗前后头颅侧位定位片进行分析比较.结果: 2 组下颌骨位置均后移,稳定在治疗前的下颌后退位处(P>0.05);2 组上颌骨长度及突度均增加,F组效果优于T组(P<0.05);F组有明显的牙齿代偿性移动(P<0.01);T组的平均疗程6.5 个月,F组为9 个月.结论: 2 种功能矫治器均能有效的使下颌后退矫治生长发育期安氏Ⅲ类错.Frankel-Ⅲ对上颌的作用大于反式Twin-Block,反式Twin-Block的治疗时间明显短于Frankel-Ⅲ.     

下颌前伸矫治器和Herbst矫治器治疗AngleⅡ类错的对比研究

目的 :比较下颌前伸矫治器 (MandibularProtractionAppliance ,MPA)和Herbst矫治器对AngleⅡ类错牙合的治疗效果。方法 :选择 2 6例AngleⅡ类错牙合病人 ,男 14例 ,女 12例 ,最大 13岁 ,最小 10岁。X线头影测量显示主要为下颌后缩及轻微上颌前突 ,手腕片显示为生长发育高峰期。将这些病人分成两组 ,一组用下颌前伸矫治器治疗 (MPA组 ) ,另一组用Herbst矫治器进行治疗 (HA组 )。功能矫治结束时 ,两组病例均摄X线头颅定位侧位片 ,由专人定点、测量 ,并进行统计学分析。结果 :X线头影测量结果显示两组病例中Co -Pg、Go -Pg及Co -Go均增大 ,其变化量经统计学检验差异无显著性意义 ,表明下颌前伸矫治器及Herbst矫治器均能促进下颌骨生长 ,尤其是下颌升支的生长 ;SNB、ANB、U1-L1、U1-NL及L1-MP的变化量经过统计学检验差异有显著性意义 ,说明下颌前伸矫治器和Herbst矫治器都能有效矫治AngleⅡ类错牙合颌骨矢状关系不调 ,尤其是前者更有效 ,而Herbst矫治器易引起支抗丢失 ,即易使上颌前牙舌向倾斜、下颌前牙唇倾。结论 :下颌前伸矫治器和Herbst矫治器治疗早期AngleⅡ类错牙合均可取得明显的骨胳改变 ,但前者治疗效果更好     

下颌前伸矫治器和Herbst矫治器治疗Angle Ⅱ类错牙合的对比研究

目的:比较下颌前伸矫治器(Mandibular Protraction Appliance,MPA)和Herbst矫治器对Angle Ⅱ类错牙合的治疗效果.方法:选择26例Angle Ⅱ类错牙合病人,男14例,女12例,最大13岁,最小10岁.X线头影测量显示主要为下颌后缩及轻微上颌前突,手腕片显示为生长发育高峰期.将这些病人分成两组,一组用下颌前伸矫治器治疗(MPA组),另一组用Herbst矫治器进行治疗(HA组).功能矫治结束时,两组病例均摄X线头颅定位侧位片,由专人定点、测量,并进行统计学分析.结果:X线头影测量结果显示两组病例中Co-Pg、Go-Pg及Co-Go均增大,其变化量经统计学检验差异无显著性意义,表明下颌前伸矫治器及Herbst矫治器均能促进下颌骨生长,尤其是下颌升支的生长;SNB、ANB、U1-L1、U1-NL及L1-MP的变化量经过统计学检验差异有显著性意义,说明下颌前伸矫治器和Herbst矫治器都能有效矫治Angle Ⅱ类错牙合颌骨矢状关系不调,尤其是前者更有效,而Herbst矫治器易引起支抗丢失,即易使上颌前牙舌向倾斜、下颌前牙唇倾.结论:下颌前伸矫治器和Herbst矫治器治疗早期Angle Ⅱ类错牙合均可取得明显的骨胳改变,但前者治疗效果更好.     

Forsus矫治器治疗恒牙初期安氏Ⅱ类错牙合的临床疗效

目的探讨Forsus矫治器的治疗对安氏Ⅱ类错牙合硬组织变化的影响。方法临床选择恒牙初期的安氏Ⅱ类错牙合患者12例,年龄11~15岁。采用Forsus矫治器治疗,治疗前、后进行X线头影测量分析,并评价其疗效。结果12例患者经过4~7个月(平均6个月)的治疗,面形改善明显,并获得Ⅰ类磨牙关系,前牙覆牙合覆盖正常。矫治前后X线头影测量结果中下颌骨的B、Pg、Co三点的变化都有显著的统计学差异;在覆盖和磨牙关系的变化中,骨性改变占总变化的38.2%和32.3%;上、下颌平面角及面下高无显著变化,但上下牙合平面发生顺时针的旋转。结论Forsus矫治器对于生长期的安氏Ⅱ类错牙合可以产生一定的生长改良作用。     

改良型生物调节器治疗Ⅱ类错

目的采用改良型生物调节器矫治生长发育期的安氏类Ⅱ错牙合儿童,以评价此矫治器对颅、颌、面软硬组织的影响.方法本文随机选择30例安氏Ⅱ类错牙合儿童,30例健康儿童作为对照组,分别拍摄X线头颅侧位片,并进行治疗前后的电子计算机-头影测量研究.结果治疗组SNA角减小,SNB角明显增大,ANB角减小,下颌骨水平向生长趋向正常.结论生物调节器矫治Ⅱ类错牙合不仅能抑制上颌生长,减小上颌突度,还能有效地促进下颌生长.     

Forsus和Dynamax矫治器对下颌骨生长改形的效果比较

目的比较Forsus矫治器与Dynamax矫治器对下颌骨形态的影响。方法选择30例治疗成功的骨性Ⅱ类错[牙合]患者,15例采用Forsus矫治器治疗,15例采用Dynamax矫治器治疗,以矫治前后的X线头影测量片评价其疗效,并进行对比。结果两种矫治器均能明显增加下颌骨长度,但Dynamax矫治器对下颌平面角的影响更大。结论在选择两种矫治器矫治骨性Ⅱ类错[牙合]患者时应考虑患者的下颌角因素。     

Twin-Block联合MBT双期矫治安氏Ⅱ^1错（牙合）的临床应用

目的：观察应用Twin-Block功能矫治器联合MBT直丝弓矫治技术双期矫治快速生长期下颌后缩性安氏Ⅱ^1错（牙合）的临床疗效。方法：选择以下颌后缩为主要临床表现的生长期安氏Ⅱ^1错（牙合）患者16例,采用双期矫治I,期应用Twin-Block功能矫治器,Ⅱ^1期应用MBT直丝弓矫治技术,应用X线头影测量分析,对患者治疗前后的硬组织变化进行分析,并对测量结果进行t检验。结果：治疗前后患者外形侧貌及覆盖改善明显。X线测量结果ANB,SNA,Go-Gn,L1-MP,ANS-Me变化有统计学意义。结论：对于快速生长期的下颌后缩性安氏Ⅱ^1错（牙合）采用双期矫治有明显疗效,可以有效改变前牙的覆盖和磨牙关系,这种改善包括骨骼效应和牙效应。     

TWin-block矫治器治疗安氏Ⅱ类错(牙合)后牙和骨骼变化的研究

目的通过X线头影测量分析,比较生长发育期安氏Ⅱ类Ⅰ分类错(牙合)患者用Twin-block矫治器治疗后,牙和骨骼的变化.方法选择14例以下颌后缩为主的安氏Ⅱ类Ⅰ分类错(牙合)患者,年龄10～12岁,后牙均为远中关系.全天戴用Twin-block矫治器9～12个月,测量治疗前后X线头颅定位侧位片,进行统计学分析.结果ANB角减小1.68°(P＜0.01),Pg-OLP增加3.23mm(P＜0.01),上切牙唇倾度(1s-NSL)减小5.61°(P＜0.01),下切牙唇倾度增加2.96°(P＜0.01),覆盖及磨牙位置关系均有显著差异(P＜0.01),腭平面角、(牙合)平面角、下颌平面角均未发生显著性改变.结论Twin-block矫治器用于早期以下颌功能性后缩为主的安氏Ⅱ类Ⅰ分类错(牙合)的功能性矫治,可取得明显的牙(牙合)骨骼的改变.     

Comparison of the cutting efficiency of two ultrasonic units utilizing two different tips at two different power settings

The objective of this in vitro study was to set up a testing protocol and utilize it to evaluate and compare the cutting efficiency of ultrasonic units. Evaluation of two ultrasonic units utilizing two different tips was done by measuring the weght of a dentin specimen before and after ultrasonic treatment for set time periods. The difference in weight was the amount of dentin removed. The ultrasonic units tested were the P5 Booster (Staelec, France) and the Spartan (Obtura-Spartan, Fenton, MO) machines. The tips tested were the CPR-2D and ETD20 types. The units were tested at maximum and medium power. All the experimental variables, ultrasonic unit type, power setting and tip type were found to have an effect on the cutting efficiency (P<0.0001). The P5 ultrasonic unit was more effective at dentin removal than the Spantan ultrasonic unit at both power settings. The ETD-20 tip was more effective at dentin removal than the CPR-2D tip on both units at both power settings.     

2种根管封闭剂对2种纤维桩剪切粘接强度的影响

目的 研究2种根管封闭剂对2种纤维桩固位力的影响.方法 将28颗完整离体上颌中切牙截冠、逐步后退法预备根管,按采用的根管封闭材料及纤维桩不同分为4组:Cortisomol封闭剂+Matchpost纤维桩(A组),Cortisomol封闭剂+Macrolock纤维桩(B组),Guttaflow封闭剂+Matchpost纤...     

The effectiveness of two sonic and two ultrasonic scaler tips in furcations

This study compared the effectiveness of two sonic and two ultrasonic scaler tips on artificial calculus removal from the furcations of mandibular first and second molars. Twenty-four extracted mandibular molars were cleaned and randomly assigned to one of four treatment groups. Teeth were split buccal lingually, artificial calculus was placed in the furcation areas, and the teeth were photographed with a stereo camera. Teeth were reconnected with bonding material and mounted in a typodont with simulated gingiva and attached to a dental chair. Teeth were instrumented with either a Cavitron TFI10 tip, Cavitron EWPP tip, Titan-S Universal tip, or Titan-S Sickle tip by a licensed dental hygienist until each tooth was judged calculus free to the touch with a CH3 explorer. Time for each instrumentation period was recorded. Following instrumentation, the teeth were again split and photographed. Stereophotogrammetry was used to produce tracings of the teeth with initial calculus and remaining calculus. Pre-instrumentation and post-instrumentation amounts of calculus on the surface area were computed using the Bioquant system. A two factor analysis of variance was conducted followed with a Newman-Keuls Multiple Comparison Technique to test for within and between differences. Significant differences (P less than or equal to 0.01) were found between pre- and post-amounts of calculus for all tips. No significant differences (P less than or equal to 0.05) were found between the four instrument tips with respect to percentage of furcation surface with calculus remaining. No differences were found between tips with regard to the time required to clean the test surfaces.     

Quantitative evaluation of marginal leakage of two resin composite restorations using two filling techniques

This in vitro study evaluated the marginal leakage of two light-cured resin composites used for posterior restorations using two filling techniques. Standardized Class V cavities were made on the enamel vestibular surface of 30 freshly extracted sound inferior bovine incisors. The teeth were randomly restored according to three experimental groups (Group 1--Z250 with 1 mm vertical increments; Group 2--Z250 with 1 mm horizontal increments; Group 3--SureFil with 1 mm horizontal increments). All samples were thermocycled (3000 cycles at 5 degrees C and 55 degrees C) with a dwell time of one minute at each temperature and immersed in a dye solution for 12 hours. After being ground into powder, the samples were individually immersed into glass tubes with absolute alcohol. The solution was centrifuged and the supernatant was analyzed using a spectrophotometer to quantify its dye concentration. Results showed that Group 2 exhibited the lowest leakage means, which was significantly different from Groups 1 and 3 (p<0.05). It was concluded that despite the lower leakage means exhibited by medium viscosity composites, no restorative material or filling technique was able to avoid leakage.     

Endodontic treatment of mandibular incisors with two root canals: report of two cases

The root canal anatomy of mandibular incisors can present a number of variations, including multiple canals. Two case reports are presented to illustrate the serendipitous discovery and successful non-surgical endodontic management of complex canal systems in mandibular incisors. In both cases, all four mandibular incisors had two canals each.     

Bond strength of three porcelains to two forms of titanium using two firing atmospheres

STATEMENT OF PROBLEM: Problems with casting and porcelain bonding are encountered when titanium is used in metal-porcelain restorations. The oxidation characteristics of titanium are the main problem. The bonding mechanisms in titanium-porcelain systems are complex and poorly understood. PURPOSE: An in vitro investigation was performed to evaluate the bonding characteristics of 3 titanium-porcelain systems in various firing conditions. MATERIAL AND METHODS: This study evaluated the bonding strength of 3 commercial titanium porcelains fired in a vacuum and in an argon atmosphere to cast and noncast commercially pure titanium, using a 3-point bending test according to DIN 13927 and SEM with energy-dispersive spectrometry analysis. The results were compared with an Ni-Cr alloy and a conventional porcelain that was chosen as a control. RESULTS: The Ni-Cr-conventional porcelain system fired in an argon atmosphere had significantly higher bond strength than the other systems (P<.001). In addition, the bond strength of the titanium-spark erosion-Noritake Ti22 combination, fired in an argon atmosphere, was significantly higher than the other titanium-porcelain groups, which had results similar to those obtained with the vacuum-fired, Ni-Cr-conventional porcelain and argon-fired titanium-cast-Noritake Ti22 groups. On the other hand, the bond strength of the titanium-TiBond and titanium-Vita Titankeramik groups was below the lower limit value in the DIN 13927 standard for the 3-point bending test (25 MPa). Although the results of the Duncan multiple range test showed that firing in an argon atmosphere did not affect the bond strength of the titanium-Vita Titankeramik groups, the titanium-spark erosion-TiBond group, or the titanium-cast-Noritake Ti22 group, argon firing improved the bond strengths of the Ni-Cr-conventional porcelain group, the titanium-cast-TiBond group, and the titanium-spark erosion-Noritake Ti22 porcelain group. It was also found that there were no significant differences between the bond strengths of cast and non-cast titanium groups; an exception was the titanium TiBond groups in which the porcelain was fired in a vacuum. CONCLUSION: The oxide layer produced on titanium was considered to have a potentially adverse effect on titanium-porcelain bonding. It was also concluded that matching the titanium-porcelain combination is the main determinant for optimal bonding. Firing in an argon atmosphere that limited the oxidation of titanium improved the titanium-porcelain bond in some of the groups.