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991.
992.
Warattama Suksaphar Danuchit Banomyong Titalee Jirathanyanatt Yaowaluk Ngoenwiwatkul 《Journal of endodontics》2018,44(2):233-238
Introduction
The aim of the present study was to compare the survival rates against fracture of premolar endodontically treated teeth (ETT) restored with resin composite or crowns and to identify risk factors associated with the fracture.Methods
Data from dental records and radiographs of premolar ETT with postendodontic restorations (ie, resin composite or crowns) were collected between 2012 and 2016 and selected following selected inclusion and exclusion criteria. Tooth location, type of restoration, number of proximal contacts, and amount of tooth surface loss were recorded. The incidence and restorability of postendodontic fractures were identified. Survival rates against fracture of the 2 restoration types were calculated using Kaplan-Meier survival analysis. Any potential factors associated with fractures were identified using Cox proportional hazards models.Results
The survival rate against fracture of ETT restored with crowns (95.1%) was higher than resin composite (77.0%). ETT restored with resin composite with 1 or 2 tooth surface losses and 2 proximal contacts had a high survival rate of 88.5% that was not significantly different from ETT with crowns. A higher incidence of restorability after fracture was observed in teeth restored with resin composite than crowns. The type of restoration and number of proximal contacts were identified as potential risk factors associated with fracture incidence.Conclusions
The survival rate against fracture of ETT restored with crowns was higher than resin composite. However, ETT with 1 or 2 tooth surface losses and 2 proximal contacts and restored with resin composite showed a high survival rate that was comparable with ETT restored with crowns. 相似文献993.
Ririko Tsuboi Jun-Ichi Sasaki Haruaki Kitagawa Itsumi Yoshimoto Fumio Takeshige Satoshi Imazato 《Dental materials》2018,34(4):641-648
Objective
Aiming to achieve bioactive dental resins that promote healing of surrounding tissues, we developed novel poly(2-hydroxyethyl methacrylate/trimethylolpropane trimethacrylate) (polyHEMA/TMPT) particles. These particles have been reported to be useful as a non-biodegradable carrier for fibroblast growth factor-2 (FGF-2) in vitro. The aim of this study was to evaluate the ability of an adhesive resin incorporating FGF-2-loaded polymer particles to promote tissue regeneration in vitro and in vivo.Methods
Experimental adhesive resins were prepared by incorporating FGF-2-loaded polyHEMA/TMPT particles into a 4-META/MMA-based adhesive resin, and the release profiles of FGF-2 were evaluated. The proliferation of osteoblast-like cells in the eluate from cured experimental resin was assessed. When the experimental resin was implanted into rat calvaria defects, bone regeneration was evaluated by microcomputed tomography and histological observations.Results
Sustained release of FGF-2 from the experimental resin was observed for 14 days. Eluate from the cured experimental resin significantly promoted the proliferation of osteoblast-like cells. Significantly greater bone regeneration was observed using the experimental resin compared with the control resin without FGF-2.Significance
4-META/MMA-based adhesive resin incorporating FGF-2-loaded polymer particles is useful to promote tissue regeneration, suggesting that its application would be beneficial for root-end filling or the repair of fractured roots in cases with severely damaged periodontal tissue. 相似文献994.
Krisztina Mikulás Péter Hermann István Gera Timea Komlódi Gergő Horváth Attila Ambrus László Tretter 《Dental materials》2018,34(7):e166-e181
Objectives
Earlier studies demonstrated that dental resin monomers lower cellular viability and provoke oxidative stress. Reactive oxygen species (ROS) formation has a key role in triethylene glycol dimethacrylate (TEGDMA) induced adverse reactions. In the present study the effects of TEGDMA on mitochondrial functions were investigated to identify a direct molecular target for cytotoxicity.Methods
Mitochondria were isolated from guinea pig brain. The most important bioenergetic parameters, oxygen consumption, membrane potential (ΔΨm), and ATP production were assessed. Mitochondrial H2O2 production and elimination and the NAD(P)H level reported on redox balance.Results
Mitochondria were supported with respiratory substrates to be oxidized by either Complex I (CI) or Complex II (CII). ΔΨm was depolarized, respiration and ATP production was greatly diminished when applying CI substrates in the presence of TEGDMA. The same parameters remained essentially unaffected when CII substrate plus TEGDMA were applied. H2O2 production by mitochondria was significantly stimulated by TEGDMA in the presence of CI substrates. In the presence of TEGDMA mitochondrial elimination of exogenous H2O2 was impaired. When CII substrate supported the mitochondria in the absence of ADP the H2O2 generation was decreased. NADH autofluorescence results also demonstrated the inhibitory effect of TEGDMA on CI activity.Significance
TEGDMA inhibits CI in the respiratory chain, which explains effects induced by TEGDMA on redox homeostasis, apoptotic and necrotic cell deaths described in previous studies. Identification of the molecular target of TEGDMA may influence the development of relevant biomaterials and may induce new therapeutic strategies to control the adverse effects of resin monomers. 相似文献995.
Muna Q. Marashdeh Russel Gitalis Celine Levesque Yoav Finer 《Journal of endodontics》2018,44(4):609-613
Introduction
After root canal treatment, the dentin-sealer interface undergoes degradation, allowing for interfacial microbial biofilm proliferation and treatment failure. Saliva and cariogenic bacteria showed esterase-like activities (ie, cholesterol esterase [CE]-like and/or pseudocholinesterase [PCE]-like) that degrade methacrylate-based resin materials and/or the restoration-tooth interface, increasing microbial interfacial proliferation. Enterococcus faecalis is a gram-positive bacterium that is commonly detected in persistent endodontic infections. The aim of this study was to measure E. faecalis esterase-like, CE-like, and PCE-like activities and to assess the ability of the bacterium to degrade methacrylate-based resin composite (RC) and total-etch (TE) and self-etch (SE) adhesives.Methods
CE-like and PCE-like activities from E. faecalis were measured using nitrophenyl and butyrylthiocholine substrates, respectively. The ability of E. faecalis to degrade resin composite, total-etch and self-etch adhesives was examined by quantifying the release of a universal resin degradation by-product (ie, Bis[hydroxypropoxy]-phenyl propane [BisHPPP]) using high-performance liquid chromatography.Results
E. faecalis showed CE-like (1.23 ± 0.13 U/μg dry bacteria) but no PCE-like activity. After 30 days and/or 14 days of incubation, the amount of BisHPPP released was significantly higher in the presence of bacteria versus media for TE and RC but not SE (P < .05). The amount of BisHPPP released after 30 days of incubation with bacteria was highest for TE (23.69 ± 1.72 μg/cm2) followed by RC (3.43 ± 1.20 μg/cm2) and lowest for SE (0.86 ± 0.44 μg/cm2) (P < .05).Conclusions
E. faecalis possesses esterase-like degradative activity toward dental methacrylate resin restoration materials, which could accelerate the degradation of the dentin-methacrylate resin interface, increasing bacterial biofilm proliferation and penetration into the root canal system. 相似文献996.
Marina Lermenn Vidal Guilherme Ferreira Rego Gil Mendes Viana Lucio Mendes Cabral Juliana Primo Basílio Souza Nick Silikas Luis Felipe Schneider Larissa Maria Cavalcante 《Dental materials》2018,34(1):143-151
Objective
Investigate physical and chemical properties of model composites formulated with quaternary ammonium salt monomers (QAS) at different concentrations and alkyl chains lengthsMethods
QAS with 12 dimethylaminododecyl methacrylate (DMADDM) and 16 dimethylaminohexadecyl methacrylate (DMAHDM) chains lengths were synthesized and incorporated at 5 and 10% in model composites, resulting in four groups: G12.5 (DMADDM 5%), G12.10 (DMADDM 10%), G16.5 (DMAHDM 5%), G16.10 (DMAHDM 10%). One group was used as control group (CG 0%). Degree of conversion (DC); water sorption (WS) and solubility (SL); hygroscopic expansion (HE); degradation temperature (DT); glass transition temperature (Tg) and polymerization shrinkage (PS) were determined. Knoop hardness (KNH), flexural strength (FS) and elastic modulus (EM) were measured before and after storage Data were submitted to ANOVA and Tukey's test (p ≤ 0.05).Results
DC ranged between 76.1 (G12.10) and 70.7 (G16.5) %; CG had the lowest WS, SL and HE. There was no statistical difference for PS and FS. KHN values ranged between 30.2 (GC) and 25 (G16.10) and after storage the performance was depended on QAS concentration and chain length. For EM, CG had the highest values before and after storage and no difference was observed in the QAS groups before storage. After storage, the results were dependent on QAS concentration (3.5-4.3 GPa).Significance
In general, the addition of QAS increased composite’s degradation compared with the CG. In the tested QAS, the addition of DMADDM at 5% concentration resulted in a less degradable material. 相似文献997.
Objective
To compare mechanical performance and enamel-crack propensity of direct, semi-direct, and CAD/CAM approaches for large MOD composite-resin restorations.Methods
45 extracted maxillary molars underwent standardized slot-type preparation (5-mm depth and bucco-palatal width) including immediate dentin sealing (Optibond FL) for the inlays (30 teeth). Short-fiber reinforced composite-resin (EverX Posterior covered by Gradia Direct Posterior) was used for the direct approach, Gradia Direct Posterior for the semi-direct, and Cerasmart composite resin blocks for CAD/CAM inlays. All inlays were adhesively luted with light-curing composite-resin (preheated Gradia Direct Posterior). Shrinkage-induced enamel cracks were tracked by transillumination photography. Cyclic axial isometric chewing (5-Hz) was simulated, starting with a load of 200 N (5000 cycles), followed by stages of 400, 600, 800, 1000, 1200, and 1400 N (maximum 30,000 cycles each) until fracture or to a maximum of 185,000 cycles. Survived specimens were subjected to cyclic-load-to-failure test at 30-degree angle on the palatal cusp.Results
Only small shrinkage-induced cracks were found in 47% of the direct restorations compared to 7% and 13% of semi-direct and CAD/CAM inlays, respectively. Survival to accelerated fatigue was similar for all three groups (Kaplan–Meier p > .05) and ranged between 87% (direct) and 93% (semi-direct and CAD/CAM). Cyclic-load-to-failure tests did not yield significant differences either (Life Table analysis, p > .05) with median values of 1675 N for CAD/CAM inlays, 1775 N for fiber-reinforced direct restorations and 1900 N for semi-direct inlays.Significance
All three restorative techniques yielded excellent mechanical performance above physiological masticatory loads. Direct restorations performed as good as inlays when a short-fiber reinforced composite-resin base was used. 相似文献998.
Hongyan Chen Ruili Wang Jiadong Zhang Hongfei Hua Meifang Zhu 《Dental materials》2018,34(12):1846-1855
Objective
The aim of this study is to explore the reinforcing effect and the antimicrobial activity of the core-mesoporous shell structured ZnO@m-SiO2, which possesses the micromechanical resin matrix/filler interlocking in dental composites, and to investigate the effect of filler compositions on their physical-mechanical properties.Methods
ZnO@m-SiO2 was synthesized by a simple self-assembly method and then characterized by electron microscopy, X-ray diffraction (XRD) and N2 adsorption/desorption measurements. Mechanical properties of dental composites reinforced with ZnO@m-SiO2 and nonporous SiO2 particles were measured with a universal mechanical testing machine. Fracture morphologies of these composites were observed by field-emission scanning electron microscopy (FE-SEM), and their antimicrobial activities were evaluated according to the ASTM E 2180-07 (2012) method. Resin composites containing unimodal silanized SiO2 were served as the control group.Results
The impregnation of lower loading of ZnO@m-SiO2 (≤7 wt%) into dental composites including silanized SiO2 substantially increased their mechanical properties. Among all composites, the optimal composite Z7S63 (ZnO@m-SiO2: silanized SiO2 = 7:63, wt/wt, total filler loading 70 wt%) demonstrated the best flexural strength, flexural modulus and compression strength, which were increased by 121.2, 67.1 and 32.5%, respectively, in comparison with the control composite Z0S70. In addition, this optimal composite also exhibited superior antimicrobial activity (>99.9%) and acceptable degree of conversion, polymerization shrinkage and curing depth.Significance
The incorporation of ZnO@m-SiO2 and silanized SiO2 as bimodal fillers led to the design and formulation of dental composites with excellent comprehensive performance, especially the improved mechanical properties and the superior antimicrobial activity. 相似文献999.
Fabrication of an Implant‐Supported Fixed Interim Prosthesis Using a Duplicate Denture: An Alternative Technique 
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下载免费PDF全文 The fabrication of an implant‐supported fixed complete denture prosthesis involves multiple clinical and laboratory steps. One of the main steps is to provide the patient with an interim fixed prosthesis to evaluate the patient's esthetic and functional needs as well as to enhance the patient's psychology before proceeding to the definitive prosthesis. Different techniques for fabricating interim prostheses have been described in the literature. This report describes an alternative technique that uses a duplicate denture made of self‐curing acrylic resin to fabricate an implant‐supported fixed interim prosthesis. The interim prosthesis was later used as a blueprint for the definitive implant‐supported hybrid prosthesis. 相似文献
1000.
目的 评价牙本质表面玷污层的特性对自粘接型树脂水门汀粘接强度和耐久性的影响。方法 将48颗新鲜无龋的人第三恒磨牙暴露出牙本质表面,分别用标准粒径（105~125 μm）金刚砂车针（A组）和标准粒径+细粒径（25 μm）金刚砂车针进行研磨（B组）。研磨后的牙齿分别与Clearfil SA Cement（CSA）和Multilink Speed（MS）两种自粘接型复合树脂水门汀粘接,制成微拉伸试件,试件分别在水中存储24 h和2年,进行微拉伸强度测试,断裂后的试件使用体视显微镜观察粘接界面并记录断裂模式。采用扫描电子显微镜（SEM）观察研磨后的牙本质表面及牙本质-树脂粘接界面。结果 A组SEM观察到研磨后牙本质表面粗糙,玷污层较厚,牙本质小管口未完全栓塞;B组牙本质表面粗糙程度降低,牙本质小管口完全栓塞,玷污层变薄。CSA和MS的B组初期粘接强度显著低于A组（P<0.05）;CSA和MS的粘接强度在水储存2年后出现显著降低（P<0.05）,CSA的B组粘接强度显著低于A组（P<0.05）,而MS的A组与B组间的粘接强度无明显差异（P>0.05）。结论 牙本质表面玷污层特点及自粘接型树脂水门汀类型都会对粘接强度及耐久性产生影响。 相似文献