计算机辅助设计与辅助制作氧化锆全瓷冠的临床效果初探

目的 评价计算机辅助设计与辅助制作氧化锆全瓷冠的临床修复效果,为其临床应用提供参考.方法 选择于北京大学口腔医学院·口腔医院修复科就诊的磨牙牙体缺损患者60例.30例患者共计35颗患牙用三维激光扫描仪获取工作模型、对验模型及咬合记录的三维数据;用软件的全冠设计程序设计有咬合关系及邻牙接触关系的全解剖形态氧化锆全瓷单冠;用数控机床和氧化锆块制作、终烧结并上釉完成最终修复体,临床试戴并粘固(全瓷冠组).30例患者共计30颗患牙制作金合金铸造单冠(铸造冠组).参考改良的美国公共卫生署评价标准,戴冠后即刻、3、6、12、24个月临床观察和评价修复体外形、颜色、自身和对(牙合)牙磨耗及修复体破损情况.结果 35件氧化锆全瓷冠均未出现崩瓷及折裂,修复后24个月5例患者5件全瓷冠对(牙合)牙出现Ⅰ级磨耗,1例患者1件全瓷冠对(牙合)牙由修复后即刻的Ⅰ级磨耗变为Ⅱ级磨耗,全瓷冠抛光后对(牙合)牙磨耗未进展.30件金合金铸造冠无磨穿等破损现象,对(牙合)牙无明显磨耗.结论 用氧化锆全瓷冠修复磨牙牙体缺损,美观程度较好、不易破损、磨耗,但氧化锆全瓷冠可在一定程度上磨耗其对(牙合)天然牙,应严格把握临床适应证.     

CAD/CAM氧化锆及Empress全瓷冠修复三年临床效果比较

目的:比较CAD/CAM氧化锆及Empress全瓷冠修复3年的临床效果。方法:选择350例患者共838个全冠修复体(其中CAD/CAM氧化锆全冠428颗、Empress铸瓷全冠410颗),平均观察期36.2±5月,随访检查基牙和修复体情况,分别对两组全瓷冠的存留率和修复成功率进行统计学分析。结果:观察期内共有41颗全瓷冠(19颗为氧化锆,22颗为Empress铸瓷)完全失败,需重新制作。氧化锆全瓷冠和Empress铸瓷全冠的存留率分别为95.1%和95.8%,成功率分别为90.7%和91.2%,其差异均无统计学意义。结论:CAD/CAM氧化锆和Empres铸瓷全冠均能满足临床需要,有较好的修复效果。     

氧化铝全瓷冠修复前牙牙体缺损的临床效果评价

目的探讨氧化铝全瓷冠修复前牙牙体缺损的临床疗效。方法 Procera氧化铝全瓷冠修复前牙牙体缺损患者174例,患牙327颗,6个月后参照美国公共健康协会的修正标准评价修复体形态、基牙继发龋、修复体边缘密合度、修复体磨损及折裂情况。结果 174例327件Procera氧化铝全瓷冠修复体复诊154例292件,修复体边缘适应性的合格率为100%,修复体形态合格率为99.7%,磨损和折裂的合格率是99.7%,无基牙继发龋,仅1件修复体崩瓷。患者对美学效果均感满意。结论 Procera氧化铝全瓷冠修复前牙牙体缺损临床效果理想,美学效果良好。     

非金属桩核冠系统在磨牙大面积缺损修复中的应用

目的 评价磨牙大面积牙体缺损采用纤维桩及全瓷冠修复的短期临床效果.方法 28例患者,共33颗磨牙残冠根采用纤维桩及全瓷冠修复.于修复体黏固后1周、1个月及6 ～ 24个月复查,评价修复体完整性,边缘适合度,牙周组织健康状况及根尖周健康状况.结果 93.9%的修复体保持完整.有2颗修复体发生崩瓷或折裂,为咬硬物所致.所有修复体边缘适合性良好,色泽稳定,牙龈状况良好.纤维桩及树脂核无松动、折裂、缝隙等.X线片未见根尖异常,未见根折或桩折.结论 在严格掌握适应证的条件下,将纤维桩及全瓷冠用于磨牙残根残冠修复能够取得良好的近期临床效果.     

CAD/CAM氧化锆全瓷冠修复临床疗效评价

目的：探讨CAD／CAM氧化锆全瓷冠的修复效果。方法：选择82例（192颗患牙）,分别在CAD／CAM氧化锆全瓷冠粘接后1、3、6、12个月进行随访观察。采用美国公共健康协会的修订标准对修复体的临床效果进行评价。结果：观察期间失访4例,随访78例共181件修复体,结果显示CAD／CAM全瓷冠颜色达到好以上91．2％,CAD／CAM氧化锆全瓷冠的崩瓷率2．76％,与修复体部位有明显相关性（P〈0．01）,在粘接12个月后有1个修复体的边缘密合度欠佳,所有复诊患者在12个月的临床观察中均未见边缘着色,继发龋和基牙松动。结论：氧化锆全瓷修复体具有良好的稳定性和生物相容性,近期临床效果满意。     

CAD/CAM氧化锆全瓷单冠抗折裂随访4年临床分析

目的 回顾分析评价CAD/CAM氧化锆全瓷单冠抗折裂性能。 方法 为189例患者制作CAD/CAM氧化锆全瓷冠284颗,随访到156例患者的226颗全瓷冠,随访2.5~5.5年,对修复体的位置、崩瓷、基底冠折断、修复体松动脱落等情况进行观察。 结果 CAD/CAM全瓷冠1年的折裂率0.9%,2年的折裂率为2.1%,3年的折裂率为3.3%,4年的折裂率为7.1%,观察期间全瓷冠的总折裂率为9.7%。其中2例患者发生基底冠折裂。当对颌分别为天然牙或瓷修复体时,全瓷冠的折裂率有显著性差异（P=0.034）。全瓷冠的折裂后牙明显高于前牙区（P<0.01）。 结论 CAD/CAM氧化锆全瓷冠整体抗折裂性能临床可接受,可作为临床首选的美学修复体。     

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目的评价Ceramage聚合瓷高嵌体和多面嵌体修复后牙牙体缺损的临床效果。方法选择2005年1月至2008年1月于中国医科大学口腔医学院修复科就诊的后牙牙体缺损患者129例(患牙200颗),行Ceramage聚合瓷高嵌体和多面嵌体修复各100颗牙,于患者戴用修复体后6个月、1年、2年、3年,检查其形态、边缘适合性、颜色、周围龋、修复体磨耗程度、接点及折裂情况。结果200颗患牙修复后中共出现5颗失败,其中高嵌体修复体破损1颗、松动1颗、食物嵌塞2颗;多面嵌体修复体未发现有破损,1颗出现基牙折裂。结论Ceramage聚合瓷是一种很好的后牙牙体缺损修复材料;与高嵌体相比,多面嵌体保留了更多牙体组织,更有利于修复体力学或生物学的使用周期。     

瓷基台在前牙种植修复中的临床应用

目的：评估氧化铝或氧化锆瓷基台支持的种植全瓷修复体的近期临床疗效.方法：病例包括由相同的临床操作者连续完成的10例患者共17颗种植全瓷修复体.考察瓷基台有无松动及瓷基台支持的全瓷冠有无破损、折裂,同时观察全瓷修复的美学效果.观察时间为完成修复后4个月到22个月.结果：10例患者17颗瓷基台全瓷冠修复体在4～22个月内疗效良好.瓷基台及全瓷冠无松动.全瓷冠未见折裂、破损现象.患者均对全瓷修复的美学效果满意.结论：氧化铝或氧化锆瓷基台支持的种植全瓷修复方法可行,美学效果满意,其长期效果有待进一步观察.     

氧化锆全瓷冠修复上颌前牙牙体缺损的临床效果

目的评价氧化锆全瓷冠修复上颌前牙牙体缺损的临床效果。方法上颌前牙牙体缺损患者49例共134颗患牙,使用氧化锆全瓷冠进行前牙美学修复。全瓷冠粘固后6、12个月进行复诊检查,根据美国公共健康协会口腔临床修复材料评价修正标准对全瓷冠的外形、边缘适合性、表面质地、颜色匹配性、边缘染色等进行评价。结果 3颗全瓷冠粘固后2周因咬硬物崩瓷,其余无破损、松动、脱落,牙体无折断、劈裂和继发龋等并发症。修复后6、12个月复查,修复体外形、表面质地、边缘染色、固位、术后敏感性、牙龈健康、继发龋7项标准在2次评价中均达到了A级;边缘适合性在修复后6个月复查时A级占97.8%(131/134),在修复后12个月复查时A级占96.3%(129/134);颜色匹配性两次复诊时A级均占92.5%(124/134)。结论掌握合理的适应证和规范化的操作,采用氧化锆全瓷冠修复上颌前牙牙体缺损能达到满意的临床效果。     

CAD/CAM氧化锆全瓷冠桥随访4年的临床分析

目的:回顾分析评价CAD/CAM氧化锆全瓷冠桥的修复效果.方法:为267位患者制做CAD/CAM氧化锆全瓷冠或桥681件,随访了205例患者的562件全瓷冠桥,随访时间2-6年.对修复体的崩瓷、全瓷冠的颜色与修复体的边缘密合度进行评价.结果:CAD/CAM氧化锆全瓷冠的崩瓷率3.31%,与修复体部位有明显相关性(P＜0.01),不同技术员完成的CAD/C氧化锆全瓷冠的颜色效果有明显不同(P＜0.001),不同颜色预备体的修复体后颜色效果没有明显差异(P＞0.05),CAD/CAM全瓷冠颜色达到好以上90.8%,CAD/CAM全瓷修复体的边缘密合度达到好的99.2%,长桥边缘密合度欠佳,修复体松动脱落0.35%,随访期间没有发现CAD/CAM全瓷修复体基底冠或桥支架折断.结论:CAD/CAM全瓷冠颜色接近天然牙,特别是预备体变色时是115床旨选的美学修复体,CAD/CAM全瓷冠边缘密合度好,整体崩瓷率可接受,但长桥边缘密合度需进一步提高,且磨牙的崩瓷率须进一步研究降低.     

计算机辅助设计和制造全瓷冠在前牙修复的临床效果

目的比较计算机辅助设计和制造全瓷冠与钴铬合金烤瓷冠在前牙修复的临床效果。方法采用计算机辅助设计和制造技术制作89件前牙二氧化锆全瓷冠,采用钴铬合金烤瓷冠制作67件前牙修复体,修复后1年复查,对边缘着色、龈缘密合度、修复体颜色、修复体周围龋、修复体折裂、牙龈健康情况进行评价。结果在边缘着色、龈缘密合性、修复体颜色、牙龈健康状况方面差异有统计学意义(P<0.05),全瓷冠的临床效果优于钴铬合金烤瓷冠。结论计算机辅助设计和制造全瓷冠的临床修复效果良好,是前牙修复的理想选择。     

Resistance to fracture of two all-ceramic crown materials following endodontic access

STATEMENT OF PROBLEM: There is currently no protocol for managing endodontic access openings for all-ceramic crowns. A direct restorative material is generally used to repair the access opening, rendering a repaired crown as the definitive restoration. This endodontic procedure, however, may weaken the restoration or initiate microcracks that may propagate, resulting in premature failure of the restoration. PURPOSE: The purpose of this in vitro study was to evaluate how an endodontic access opening prepared through an all-ceramic crown altered the structural integrity of the ceramic, and the effect of a repair of this access on the load to failure of an all-ceramic crown. MATERIAL AND METHODS: Twenty-four alumina (Procera) and 24 zirconia (Procera) crowns were fabricated and cemented (Rely X Luting Plus Cement) onto duplicate epoxy resin dies. Twelve crowns of each were accessed to simulate root canal treatment therapy. Surface defects of all accessed specimens were evaluated with an environmental scanning electron microscope. The specimens were repaired with a porcelain repair system (standard adhesive resin/composite resin protocol) and were loaded to failure in a universal testing machine. Observations made visually and microscopically noted veneer delamination from the core, core fracture, shear within the veneer porcelain, or a combination thereof. A Kruskal-Wallis test was used to determine if a significant difference (alpha=.05) in load to failure existed between the 4 groups, and a Mann-Whitney test with a Bonferroni correction (P<.0125) was used for multiple comparisons. A Weibull analysis was also used to estimate the Weibull modulus and characteristic failure for each group. RESULTS: All specimens exhibited edge chipping around the access openings. Some displayed larger chips within the veneering porcelain, and 4 zirconia crowns showed radial crack formation. There was a significant difference in load to failure among all groups with the exception of the alumina intact and repaired specimens (P=.695). The alumina crowns generally showed fracture of the coping with the veneering porcelain still bonded to the core, whereas the zirconia copings tended not to fracture but experienced veneering porcelain delamination. CONCLUSION: Endodontic access through all-ceramic crowns resulted in a significant loss of strength in the zirconia specimens but not in the alumina specimens.     

氧化锆全瓷冠与贵金属烤瓷冠修复体生物相容性比较的回顾性研究

目的：对比分析氧化锆全瓷冠与贵金属烤瓷冠修复的临床疗效。方法：60例患者的98颗牙齿进行全冠修复,其中,观察组30例（49颗）采用氧化锆全瓷冠修复,对照组30例（49颗）采用贵金属烤瓷冠修复。修复1年后按照美国加州牙科协会的全瓷修复临床标准对两组修复体的临床效果进行评价。结果：修复1年后检查,氧化锆全瓷冠的周围牙龈状况及颜色匹配优于贵金属烤瓷冠（P〈0．05）。结论：氧化锆全瓷冠修复体相比贵金属烤瓷冠具有更好的美学效果及生物相容性。     

Influence of porcelain veneering on the marginal fit of Digident and Lava CAD/CAM zirconia ceramic crowns

PURPOSE

Marginal fit is a very important factor considering the restoration''s long-term success. However, adding porcelain to copings can cause distortion and lead to an inadequate fit which exposes more luting material to the oral environment and causes secondary caries. The purpose of this study was to compare the marginal fit of 2 different all-ceramic crown systems before and after porcelain veneering. This study was also intended to verify the marginal fit of crowns originated from green machining of partially sintered blocks of zirconia (Lava CAD/CAM system) and that of crowns obtained through machining of fully sintered blocks of zirconia (Digident CAD/CAM system).

MATERIALS AND METHODS

20 crowns were made per each system and the marginal fit was evaluated through a light microscope with image processing (Accura 2000) at 50 points that were randomly selected. Each crown was measured twice: the first measurement was done after obtaining a 0.5 mm coping and the second measurement was done after porcelain veneering. The means and standard deviations were calculated and statistical inferences among the 2 groups were made using independent t-test and within the same group through paired t-test.

RESULTS

The means and standard deviations of the marginal fit were 61.52 ± 2.88 µm for the Digident CAD/CAM zirconia ceramic crowns before porcelain veneering and 83.15 ± 3.51 µm after porcelain veneering. Lava CAD/CAM zirconia ceramic crowns showed means and standard deviations of 62.22 ± 1.78 µm before porcelain veneering and 82.03 ± 1.85 µm after porcelain veneering. Both groups showed significant differences when analyzing the marginal gaps before and after porcelain veneering within each group. However, no significant differences were found when comparing the marginal gaps of each group before porcelain veneering and after porcelain veneering as well.

CONCLUSION

The 2 all-ceramic crown systems showed marginal gaps that were within a reported clinically acceptable range of marginal discrepancy.     

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目的 探讨氧化锆全瓷冠桥修复体的修复效果,为临床应用提供参考.方法 对2008年1月至2009年6月佛山市禅城区口腔医院修复科收治的40例接受全瓷修复的患者,采用计算机辅助设计与计算机辅助制作(CAD/CAM)技术制作氧化锆全瓷冠桥修复体60件,其中上颌32件,下颌28件;前牙单冠24个,后牙单冠21个,前牙固定桥2个,后牙固定桥3个(均为3单位固定桥).分别在修复体黏结后1、3、6、12个月对患者进行随访观察,采用美国加利弗尼亚牙科学会的全瓷修复临床标准对修复体的临床效果进行评价,同时也对牙周健康状况进行评价,记录全瓷修复体牙冠的牙龈出血指数(BI)、牙周袋深度(PD)以及附着丧失(AL).结果 观察期间失访3例患者5件修复体,对剩余的37例患者55件修复体的临床观察结果显示,在黏结1个月后有2件修复体的边缘卡探针,有2颗氧化锆全瓷冠修复的牙齿出现牙龈炎.在黏结3个月后,有1个单冠出现裂纹,1例固定桥断裂,2颗牙齿出现牙龈红肿.在黏结6个月后,有1例桩核冠脱落,2颗牙齿出现牙髓炎或根尖周炎.所有复诊患者在12个月的临床观察中均未见边缘着色和继发龋,有5件修复体的颜色匹配稍差.在各时间点BI、PD和AL等指标与治疗前比较差异均无统计学意义(P＞0.05),各项指标比较差异亦无统计学意义(P＞0.05).结论 氧化锆全瓷修复体具有良好的稳定性和生物相容性,近期临床效果满意.     

3种全冠修复材料对牙龈指数的影响

目的研究全瓷冠、镍铬合金烤瓷冠、钴铬合金烤瓷冠修复对患牙牙龈指数的影响。方法 100例接受全冠修复的患者共155件修复体,按修复材料分为3组,镍铬合金烤瓷组62件,钴铬合金烤瓷组50件,全瓷组43件。于修复前、修复后6个月、修复后12个月分别检测3组患牙的牙龈指数,并进行统计学分析。结果修复前、修复后6个月、修复后12个月镍铬合金烤瓷组牙龈指数分别为0.81±0.27、1.71±0.23、1.73±0.30,钴铬合金烤瓷组分别为0.80±0.25、0.79±0.20、0.89±0.20,全瓷组分别为0.83±0.33、0.78±0.29、0.89±0.32。镍铬合金烤瓷组、钴铬合金烤瓷组在修复前、修复后6个月、修复后12个月的牙龈指数呈升高趋势,差异有统计学意义(P<0.05)。全瓷组在3个时间点牙龈指数变化无统计学意义。结论全瓷冠随着时间变化,牙龈指数升高不明显,对牙龈组织的刺激小,临床效果更为优良,有利于牙周健康的维护。     

表面多孔涂层对氧化锆与饰面瓷界面结合强度的影响

目的：以表面抛光、喷砂为对照,研究表面多孔涂层对氧化锆与饰面瓷界面剪切结合强度的影响。方法：按照Schmitz-Schulmeyer法测量氧化锆与饰面瓷的剪切结合强度。制作氧化锆基底样本60个（IO×5×5mm）,分为三组（抛光组：耐水碳化硅砂纸逐级抛光至1200#;喷砂组：1lOμmA1203颗粒在3bars的压力下喷砂10sec,距离10mm;涂层组：质量分数为55wt％的氧化锆粉浆涂塑氧化锆表面,致密烧结）,每组20个。表面烧结饰面瓷（5×3×3mm）。每组取10个样本,5℃／55℃水域中交替循环5000次。万能材料试验机测试剪切结合强度,加载速度0．5mm／min。对测试结果进行双因素方差分析（α=0．05）。SEM观察样本断裂模式。结果：涂层组剪切结合强度与抛光组和喷砂组差异均有统计学意义（P〈0．05）;喷砂组与抛光组间差异无统计学意义（P〉0．05）;各组温度循环后剪切结合强度差异均无统计学意义（P〉0．05）。SEM观察显示,涂层组样本以饰面瓷的内聚断裂为主;抛光组和喷砂组以界面断裂为主。结论：表面多孔涂层可显著提高氧化锆与饰面瓷的剪切结合强度,并能耐受短期的人工老化,而结合强度无明显下降。     

Comparative fracture strength analysis of Lava and Digident CAD/CAM zirconia ceramic crowns

PURPOSE

All-ceramic crowns are subject to fracture during function. To minimize this common clinical complication, zirconium oxide has been used as the framework for all-ceramic crowns. The aim of this study was to compare the fracture strengths of two computer-aided design/computer-aided manufacturing (CAD/CAM) zirconia crown systems: Lava and Digident.

MATERIALS AND METHODS

Twenty Lava CAD/CAM zirconia crowns and twenty Digident CAD/CAM zirconia crowns were fabricated. A metal die was also duplicated from the original prepared tooth for fracture testing. A universal testing machine was used to determine the fracture strength of the crowns.

RESULTS

The mean fracture strengths were as follows: 54.9 ± 15.6 N for the Lava CAD/CAM zirconia crowns and 87.0 ± 16.0 N for the Digident CAD/CAM zirconia crowns. The difference between the mean fracture strengths of the Lava and Digident crowns was statistically significant (P<.001). Lava CAD/CAM zirconia crowns showed a complete fracture of both the veneering porcelain and the core whereas the Digident CAD/CAM zirconia crowns showed fracture only of the veneering porcelain.

CONCLUSION

The fracture strengths of CAD/CAM zirconia crowns differ depending on the compatibility of the core material and the veneering porcelain.     

The influence of different core material on the FEA-determined stress distribution in dental crowns.

OBJECTIVES: All ceramic restorations without metal have great advantages in their biocompatibility and aesthetic aspects. With the introduction of new core materials, the cores are sufficiently strong to produce long lasting all-ceramic restorations; however, the stresses in the veneering porcelain could still determine the longevity. The objective of this study was to evaluate, by finite element analysis (FEA), the influence of different core materials on the stress distribution in dental crowns. METHODS: The model of a multi-layer all-ceramic crown for posterior tooth 46 produced with CAD-CAM-technology was translated into a three-dimensional FEA program. This crown model was made with gold, zirconia, and alumina-based porcelain core and their matching veneering porcelains. The stress distribution due to the combined influences of bite forces, residual stresses caused by the difference in expansion coefficient of the core material and the veneering porcelain, and the influence of shrinkage of the cement was investigated. RESULTS: Stiffer core material does not always for various reasons result in lower stresses in the veneering porcelain. SIGNIFICANCE: This study indicates that the actual distribution of the tensile stresses and the design of restorations must be taken into account; otherwise, the significant contribution of stronger and tougher core materials to the performance of all-ceramic restorations may be offset by the weaker veneering porcelain.     

Current status of zirconia restoration

During the past decade, zirconia-based ceramics have been successfully introduced into the clinic to fabricate fixed dental prostheses (FDPs), along with a dental computer-aided/computer-aided manufacturing (CAD/CAM) system. In this article (1) development of dental ceramics, (2) the current status of dental CAD/CAM systems, (3) CAD/CAM and zirconia restoration, (4) bond between zirconia and veneering ceramics, (5) bond of zirconia with resin-based luting agents, (6) surface finish of zirconia restoration and antagonist enamel wear, and (7) clinical evaluation of zirconia restoration are reviewed.Yttria partially stabilized tetragonal zirconia polycrystalline (Y-TZP) showed better mechanical properties and superior resistance to fracture than other conventional dental ceramics. Furthermore, ceria-stabilized tetragonal zirconia polycrystalline and alumina nanocomposites (Ce-TZP/A) had the highest fracture toughness and had resistance to low-temperature aging degradation. Both zirconia-based ceramics have been clinically available as an alternative to the metal framework for fixed dental prostheses (FDPs). Marginal adaptation of zirconia-based FDPs is acceptable for clinical application. The most frequent clinical complication with zirconia-based FDPs was chipping of the veneering porcelain that was affected by many factors. The mechanism for the bonding between zirconia and veneering ceramics remains unknown. There was no clear evidence of chemical bonding and the bond strength between zirconia and porcelain was lower than that between metal and porcelain.There were two alternatives proposed that might avoid chipping of veneering porcelains. One was hybrid-structured FDPs comprising CAD/CAM-fabricated porcelain parts adhering to a CAD/CAM fabricated zirconia framework. Another option was full-contour zirconia FDPs using high translucent zirconia. Combined application of silica coating and/or silane coupler, and 10-methacryloyloxydecyl dihydrogen phosphate is currently one of the most reliable bonding systems for zirconia. Adhesive treatments could be applied to luting the restorations and fabricating hybrid-structured FDPs. Full-contour zirconia FDPs caused concern about the wear of antagonist enamel, because the hardness of Y-TZP was over double that of porcelain. However, this review demonstrates that highly polished zirconia yielded lower antagonist wear compared with porcelains. Polishing of zirconia is possible, but glazing is not recommended for the surface finish of zirconia.Clinical data since 2010 are included in this review. The zirconia frameworks rarely got damaged in many cases and complications often occurred in the veneering ceramic materials. Further clinical studies with larger sample sizes and longer follow-up periods are required to investigate the possible influencing factors of technical failures.