All-ceramic inlay-retained fixed dental prostheses for replacing posterior missing teeth: A systematic review

Purpose

To evaluate the current status of all-ceramic inlay-retained fixed dental prostheses (CIR-FDPs) for the replacement of posterior teeth.

Marginal accuracy of combined tooth–implant‐supported fixed dental prostheses after in vitro stress simulation

Objectives: Caries, periodontal disease, and peri‐implant inflammation caused by deficient marginal adaptation of fixed prostheses are reasons for clinical failure of combined tooth–implant‐supported fixed dental prostheses (TISFDP). This in vitro study examined the marginal accuracy in TISFDP after simulated stress in an artificial oral environment. Materials and methods: Twelve three‐unit TISFDPs were fabricated using a high noble alloy on models containing a human premolar with an artificial periodontium and an implant. Four three‐unit tooth‐supported prostheses (TSFDP) represented the control group. The experimental TISFDPs (four per group) were luted with three different cements: group 1, zinc phosphate; group 2, glass ionomer; group 3, self‐adhesive resin. The specimens were mechanically loaded (1.2 million cycles/50 N) and thermally cycled (8000 cycles with 5/55°C). The vertical marginal gap was measured before and after cementation, after chewing simulation and after thermal cycling by light microscopy (× 560). The results were subjected to statistical analysis (t‐test/one‐way analysis of variance/Bonferroni). Results: Significant increase (P≤0.05) in the marginal gap was found after cementation within the experimental TISFDPs (implants, 11.7–18.7 μm; teeth, 13.4–24.2 μm) and the control TSFDPs (28.5 μm). Comparison of groups 1 and 2 revealed significant differences for the teeth while comparison of the implants showed significant differences among all groups. Chewing simulation and thermal cycling caused statistically insignificant changes in the marginal gaps of the experimental as well as the control TSFDPs. Conclusion: The cementation of the TISFDPs with different luting materials caused a specific enlargement of the marginal gap in teeth and implants. Subsequent to simulated oral stress in an artificial oral environment, no significant changes of the marginal accuracy could be found.     

D-二聚体和FDPs联合检测在血栓性疾病中的应用

[目的]探讨D-二聚体和纤维蛋白(原)降解产物(FDPs)联合应用在血栓性疾病检测中的意义。[方法]选择2010—2011年住院患者60例,基础疾病为肺梗死、深静脉血栓,均为发病初期;另选择同时期门诊患者30例,基础疾病为非血栓性疾病。采用免疫比浊法测定D-二聚体浓度和FDPs浓度,观察两项指标的检测结果对疾病检测的敏感性。[结果]D-二聚体在肺梗死、深静脉血栓和非血栓性疾病中的阳性检出率分别是93.3%、86.7%和3.3%;FDPs在肺梗死、深静脉血栓和非血栓性疾病中的阳性检出率分别是100%、96.7%、40.0%;D-二聚体和FDP s联合检测在肺梗死、深静脉血栓和非血栓性疾病中的阳性检出率分别是100%、96.7%和3.3%。两项指标联合检测与D-二聚体、FDPs单独检测差异有显著性意义(P<0.01)。[结论]D-二聚体和FDPs联合检测较二者单独检测意义更大,能够明显的避免漏检及假阳性结果的产生,能够更加准确地为临床提供阳性数据及排除阴性疾病。     

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.     

Fracture load of tooth-implant-retained zirconia ceramic fixed dental prostheses: effect of span length and preparation design

Objectives: Evaluation of the effect of different span length and preparation designs on the fracture load of tooth–implant‐supported fixed dental prostheses (TIFDPs) manufactured from yttrium‐stabilized zirconia frameworks. Material and methods: Forty‐eight TIFDPs were manufactured using a CAD/CAM system and veneered with a press ceramic. Rigidly mounted implants (SLA, diameter 4.1 mm, length 10 mm) in the molar region with a titanium abutment were embedded in PMMA bases pairwise with premolars. All premolars were covered with heat‐shrink tubing to simulate physiological tooth mobility. Six different test groups were prepared (a) differing in the preparation design of the premolar (inlay [i]; crown [c]), (b) the material of the premolar (metal [m]; natural human [h]) and (c) the length of the TIFDPs (3‐unit [3]; 4‐unit [4]). All TIFDPs underwent thermomechanical loading (TCML) (10,000 × 6.5°/60°; 6 × 10⁵× 50 N). The load to fracture (N) was measured and fracture sites were evaluated macroscopically. Results: None of the restorations failed during TCML. The mean fracture loads (standard deviations) were 1,522 N (249) for the 3‐unit, inlay‐retained TIFDPs on a metal abutment tooth (3‐im), 1,910 N (165) for the 3‐cm group, 1,049 N (183) for group 4‐im, 1,274 N (282) for group 4‐cm, 1,229 N (174) for group 4‐ih and 911 N (205) for group 4‐ch. Initial damages within the veneering ceramic occurred before the final failure of the restoration. The corresponding loads were 24–52% lower than the fracture load values. Conclusions: All restorations tested could withstand the mastication forces expected. Fracture‐load values for 3‐ and 4‐unit inlay–crown and crown–crown‐retained TIFDPs should spur further clinical investigation.     

Evaluation of zirconium-oxide-based ceramic single-unit posterior fixed dental prostheses (FDPs) generated with two CAD/CAM systems compared to porcelain-fused-to-metal single-unit posterior FDPs: a 5-year clinical prospective study

Purpose: The purpose of this prospective clinical study was to determine the success rate of single‐unit posterior fixed dental prostheses (FDPs) with zirconia copings generated with two CAD/CAM systems, compared to porcelain‐fused‐to‐metal (PFM) single‐unit posterior FDPs after 5 years of function. Materials and Methods: From 2005 to 2006, 60 patients who needed a single‐unit FDP on a first molar in the mandibular jaw (left or right) in a private office setting were included in this study. The 60 first mandibular molars were randomly divided into three groups (n = 20): in the control group (group C), 20 PFM FDPs were included. In the other two groups CAD/CAM technology was used for the fabrication of the zirconium‐oxide copings: 20 single‐unit posterior FDPs with zirconia copings were generated with the Procera system (group P, Nobel Biocare); 20 single‐unit posterior FDPs with zirconia copings were generated with the Lava system (group L, 3M ESPE). For the ANOVA follow‐up data, the clinical life table method was applied. The statistical analysis was performed using two nonparametric tests, the log‐rank test for k‐groups and the Fisher exact test. Results: No statistically significant difference in the clinical outcome of zirconia–ceramic FDPs of both groups (P and L) evaluated together and metal–ceramic posterior single FDPs was found at 5 years of function; however, clinical data showed that technical problems, such as extended fracture of the veneering ceramic, tended to occur more frequently in the zirconia–ceramic FDP groups. The difference in the frequency of failure was statistically significant only in the comparison of groups C and P. Conclusions: Even if no statistically significant difference in the clinical outcome of zirconia–ceramic FDPs of both groups (P and L) considered together and metal–ceramic posterior single FDPs was found at 5 years of function, clinical data showed that the two zirconia–ceramic FDP groups tended to have more frequent clinical problems: for this reason all the clinical and technical variables related to the use of zirconia–ceramic FDPs generated with CAD/CAM systems should be carefully considered prior to all treatment procedures.     

蛇毒与播散性血管内凝血(DIC)的研究 Ⅰ.尖吻蝮蛇毒对狗引起的急性DIC

用尖吻蝮蛇毒(Agkistrodon acutus venom,AAV)(0.5mg/kg)静注麻醉狗。观察到AAV对狗引起血小板计数和血浆纤维蛋白原含量明显下降,“PT”和KPTT试验显著延长,血清FDP大大增加,3P试验阳性以及肾小球内呈现纤维蛋白沉积。这些结果表明,AAV对狗引起了急性DIC,因而加重由AAV直接引起的严重出血。此外,对由AAV导致的急性DIC机理作了初步讨论。     

Preservation of Hypermobile Teeth by Establishing Posterior Occlusal Support Using Implant Prostheses: A 5‐Year Follow‐Up

For patients with periodontally compromised, hypermobile teeth, implant‐supported fixed dental prostheses (FDPs) or removable dentures are often used after extracting mobile teeth. The loss of native teeth may carry social consequences, depending upon the patient's age, state of health, and degree of social functioning. This report represents successful stabilization and preservation of questionable, hypermobile teeth that have been damaged by traumatic occlusion due to the loss of posterior support with a cross‐arch splinted FDP, as well as the implementation of posterior support using implant‐supported prostheses.