种植金瓷固定桥的瓷层厚度对瓷裂影响的试验研究

作者研究了烤瓷厚度对松风一镍铬合金系列的种植金瓷固定义齿瓷裂的影响、结果表明：当瓷粉厚度达到3.5mm时，开始出现瓷裂；达到4mm时，全部样本产生瓷裂；连接体是产生裂纹的主要部位；用体视镜观察裂纹优于肉眼观察。提示应保证涂塑的体瓷粉厚度小于3．5mm，为了更好地满足此要求，可在种植体基桩与支架固位体之间做内冠。同时要求支架连接体外形和连接体处的瓷表面外形为平缓曲面，以避免连接体外的形状突然变化而引起的瓷裂     

三种不同材料烤瓷冠对龈沟液内天冬氨酸转氨酶和碱性磷酸酶水平的影响

目的:通过对不同材料的烤瓷冠修复后龈沟液(gingivalcrevicularfluid,GCF)内天冬氨酸转氨酶(aspartatetransaminase,AST)和碱性磷酸酶(alkalinephosphatase,ALP)总量的测定,来探讨内冠材料对牙周的影响。方法:选择临床病例26例,采用镍铬合金烤瓷冠、钛合金烤瓷冠和金铂合金烤瓷冠修复,分别在修复前、修复后1个月和3个月进行临床检查和取GCF,进行GCF量和AST、ALP总量的测定,从而进行分析。结果:1个月时,3组之间并未见指标差异;3个月时镍铬合金组和钛合金组之间未见指标差异,此时镍铬合金组和钛合金组分别与金铂合金组在指标上均有明显差异。结论:非贵金属对牙周组织有不利影响,同时通过测定GCF中AST和ALP的总量,可以方便的动态观察烤瓷冠对牙周的影响。     

牙本质瓷厚度对Ni-Cr合金烤瓷修复体颜色的影响

目的 探讨牙本质瓷厚度对金属烤瓷修复体颜色的影响.方法 用SHOFU Vintage Halo A2色牙本质瓷粉制作牙本质瓷为不同厚度(0.3mm、0.6mm、0.9mm、1.2mm、1.5mm)的金属烤瓷试件,用色度计测量试件的L*、a*、b*值,并计算其⊿E 和C*ab.比较试件颜色与VITA A2色比色片颜色的差...     

镍铬合金、钴铬合金和纯钛金瓷结合强度的比较

目的比较镍铬合金、钴铬合金和纯钛的金瓷结合强度和金瓷界面特征。方法执行ISO9693[1]标准,采用三点弯曲试验分别测定在常规热处理条件下的镍铬合金、钴铬合金和纯钛的金瓷结合强度。运用扫描电镜和X射线衍射进行金瓷界面分析。结果金瓷结合强度分别为:镍铬合金:(37.56±2.92)Mpa,钴铬合金:(39.06±2.79)Mpa,纯钛:(32.61±5.62)Mpa,前两者组间差异无统计学意义(P>0.05),后者与前两者组间差异有统计学意义(P<0.05)。扫描电镜和X线衍射:镍铬合金和钴铬合金与瓷之间紧密接触,无裂纹,界面过渡层15～20μm。纯钛与瓷过渡层80μm,可见孔洞。纯钛基体表面可见约2μm黑色带。结论①钴铬合金与镍铬合金的金瓷结合强度接近,都大于纯钛的金瓷结合强度。②钴铬合金、镍铬合金、纯钛的金瓷结合强度都大于25Mpa,按ISO9693标准均可应用于临床。③金瓷之间存在结合介质,形成过渡层。     

Objective evaluation of abutment tooth preparation for preformed metal crowns for primary molars in Japanese preclinical training

Evaluation of abutment tooth shape for preformed metal crowns for primary teeth in preclinical training depends on the subjective opinion of the instructor providing the training. Thus, the student's grade will likely vary according to teacher grading. In this study, we explored the potential for objective evaluation by comparing evaluations performed by teaching personnel (teacher grading) of abutment teeth for preformed metal crowns for primary teeth prepared by students at a dental school with evaluation by a three-dimensional (3D) laser morphometric system (system grading). The subjects of the evaluations were 139 abutment teeth for preformed metal crowns for primary teeth that had been prepared by fourth-year students at Asahi University School of Dentistry during preclinical pediatric dentistry training. A tooth prepared by a teacher following instruction criteria was used as the reference tooth, and system grade points were calculated from deductions made for insufficient and excessive cutting. Teacher grade points varied among teachers. We found that teachers prioritized contours of the margin, buccal and lingual sides, and adjacent surfaces in their evaluations. System grading showed that most students carried out insufficient cutting. The mean (SD) teacher and system grade points were 57.7 (9.7) and 75.7 (4.7), respectively, and these grade points were positively correlated (r = 0.500). System grading provides a simple 3D visual assessment of insufficient and excessive cutting that can be used for instructing students.     

反3/4冠抗切向脱位力的实验研究

目的:通过测量并比较金属3/4冠与金属烤瓷反3/4冠修复离体上颌中切牙抗切向脱位力的差异,论证金属烤瓷反3/4冠的抗切向脱位力能否满足临床固位要求.方法:选择20颗牙冠完整的离体上颌中切牙行牙体预备,制作金属3/4冠并就位于对应离体牙上,用万能试验机测量并统计各个样本的切向脱位力.再对20颗离体上颌中切牙行牙体预备,制作金属烤瓷反3/4冠金属底冠并就位于对应离体牙上,用万能试验机测量并统计各个样本的切向脱位力.用SPSS14.0统计软件包对测量结果进行配对T检验(parired-samples T Test).结果:①金属3/4冠的切向脱位力为0.545±0.487N.②金属烤瓷反3/4冠金属底冠的切向脱位力为2.96±1.58N.③金属3/4冠的抗切向脱位力和金属烤瓷反3/4冠金属底冠的切向脱位力差异有显著统计学意义(P<0.01).后者抗切向脱位力大于前者.结论:金属烤瓷反3/4冠修复离体上颌中切牙,其抗切向脱位力能够满足临床要求.     

Clinical and SEM evaluation of all-ceramic chair-side CAD/CAM-generated partial crowns

The effect of hardware and software on the quality of Cerec all-ceramic partial crowns was investigated in this cross-sectional study. Partial crowns (n = 818) had been adhesively placed in 496 patients between 1993 and 1997 using Cerec 1 and Cerec 2 units (groups 1 and 2) as well as Cerec 2 with wall-spacing software (group 3). From each group, 25 randomly selected partial crowns were evaluated using modified United States Public Health Service (USPHS) criteria. Of these, 12 were randomly selected in each group, replicas taken and examined in a scanning electron microscope for marginal interfacial width and for continuous margin adaptation. Interfacial width of group 1 (308 +/- 95 micro m) was significantly larger than those of groups 2 (243 +/- 48 micro m) and 3 (207 +/- 63 micro m). Continuous margin adaptation at the tooth-luting composite and luting composite-restoration interfaces showed only minor differences in groups 1 (94.5 +/- 8% and 95.5 +/- 2%), 2 (98.1 +/- 1% and 97.5 +/- 1.4%) and 3 (96.8 +/- 3% and 96.8 +/- 2%). Pooled clinical rating was excellent or good at 97% for all groups, indicating acceptable restoration quality except for one breakage in group 1.