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1.
Mater Sci Eng C Mater Biol Appl ; 126: 112116, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34082933

RESUMO

In order to prepare a titanium with a low elastic modulus and good antibacterial property to meet the requirements as a biomedical material, Ti-13Nb-13Zr-5Cu (TNZ-5Cu) alloy was prepared by high vacuum consume electric arc melting furnace and then subjected to a solution treatment at 950 °C followed by a short-term aging treatment at 600 °C, for 15 min, 30 min, 1 h and 2 h, respectively. The microstructure, mechanical property, antibacterial property and biocompatibility of TNZ-5Cu were investigated in detail. The research results have shown that the solid solution treated alloy was mainly composed of ß-phase and α″-phase, while the aged alloys of ß-phase, α″-phase, α-phase and Ti2Cu. Compared with Ti-13Nb-13Zr alloy (65 GPa) and Ti-6Al-4 V alloy (111 GPa), the elastic modulus of TNZ-5Cu alloy after solution treatment was about 72 GPa and increased with the aging treatment up to 85 GPa, and the hardness was maintained at a higher level than that of Ti-13Nb-13Zr alloys (288 HV). The bacteria plate count results showed that the antibacterial ability of TNZ-5Cu alloy increased with the extension of the aging duration from <60% at 15-30 min to >90% at 1-2 h. Cell experiments showed that all TNZ-5Cu alloy had good cell compatibility. The low modulus and the antibacterial property could provide potential to avoid stress shield and device-related inflection in the clinical application.


Assuntos
Ligas , Titânio , Ligas/farmacologia , Antibacterianos/farmacologia , Materiais Biocompatíveis , Módulo de Elasticidade , Teste de Materiais , Titânio/farmacologia
2.
Mater Sci Eng C Mater Biol Appl ; 126: 112128, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34082945

RESUMO

According to the National Center for Health Statistics, currently, more than 250,000 total hip replacements annually in the US alone, with an estimated increase to 500,000 by the year 2030. The usage of tapered junctions between the femoral neck and head gives the surgeon flexibility in implant assembly. However, these modular junctions are subjected to micro-motion that may cause chemical and fretting-corrosion at the modular junction. Therefore, it is imperative to study these forces to mitigate their effects. The current study aims to understand the effects of fretting-corrosion as a function of fretting frequencies caused by common physical activities in an in-vitro model of hip modular junctions. The fretting system has a tribological contact condition of flat-on-flat, mounted to a load frame. CoCrMo pins were polished and immersed in a synovial fluid-like electrolyte solution (Bovine calf serum 30 g/l). Electrochemical measurements were made using a potentiostat. Samples then undergo 3600 cycles at 50 µm (to simulate gross slips), with a horizontal load at 200 N, and a frequency of 0.5 Hz, 0.7 Hz, 1 Hz, and 1.5 Hz to simulate Sit Down-Stand Up, Stair Climb, Walking, and Jogging, respectively. Worn surfaces were then examined under optical and scanning electron microscopy. The evolution of free potential as a function of time for tested frequencies shows the initial potential drop and stabilized trend in the potential evolution. The sample group at a higher frequency displays a higher tendency of corrosion than a lower frequency; however, the dissipation energy decreases as a function of fretting frequency. Both electrochemical and mechanical responses correlate to the variation in the fretting frequencies. Organometallic complexes were found on the surfaces of the samples that were subjected to a slower frequency of fretting, whereas mechanical grooving was noticed on samples with a faster frequency. Hence, these preliminary studies suggest that implant failure rates may be altered based on fretting-frequencies induced by physical activity. Further studies will be required to verify the findings and explore the potential role of fretting frequency in the damage modes of the modular junction.


Assuntos
Artroplastia de Quadril , Prótese de Quadril , Animais , Bovinos , Corrosão , Teste de Materiais , Desenho de Prótese , Falha de Prótese , Propriedades de Superfície
3.
Mater Sci Eng C Mater Biol Appl ; 126: 112158, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34082963

RESUMO

The growing threat of bacterial resistance to antibiotics is driving an increasing need for new antimicrobial strategies. This work demonstrates the potential of magnesium oxychloride cements (MOC) to be used as inorganic antimicrobial biomaterials for bone augmentation. An injectable formulation was identified at a powder to liquid ratio of 1.4 g mL-1, with an initial setting time below 30 mins and compressive strength of 35 ± 9 MPa. Supplementation with Ag3PO4 to enhance the antimicrobial efficacy of MOC was explored, and shown via real time X-ray diffraction to retard the formation of hydrated oxychloride phases by up to 30%. The antimicrobial efficacy of MOC was demonstrated in vitro against Staphylococcus aureus and Pseudomonas aeruginosa, forming zones of inhibition and significantly reducing viability in broth culture. Enhanced efficacy was seen for silver doped formulations, with complete eradication of detectable viable colonies within 3 h, whilst retaining the cytocompatibility of MOC. Investigating the antimicrobial mode of action revealed that Mg and Ag release and elevated pH contributed to MOC efficacy. Sustained silver release was demonstrated over 14 days, suggesting the Ag3PO4 modified formulation offers two mechanisms of infection treatment, combining the inherent antimicrobial properties of MOC with controlled release of inorganic antimicrobials.


Assuntos
Anti-Infecciosos , Magnésio , Antibacterianos/farmacologia , Anti-Infecciosos/farmacologia , Cimentos Ósseos , Suplementos Nutricionais , Magnésio/farmacologia , Teste de Materiais , Fosfatos , Compostos de Prata
4.
Int J Comput Dent ; 24(2): 147-155, 2021 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-34085500

RESUMO

BACKGROUND: The esthetic outcome of a dental restoration largely depends on the translucency of the materials used, especially for monolithic restorations. Research has been published reporting a correlation between translucency and material thickness. However, no mathematical formula has been described yet. The aim of the present study was to determine the mathematical relationship between material thickness and translucency of three dental ceramic materials. MATERIAL AND METHODS: Three representative all-ceramic materials were taken out of the group of silicate ceramics (IPS Empress CAD LT), lithium X-silicate ceramics (IPS e.max CAD LT), and oxide ceramics (Lava Plus HT). Sixty specimens with five different thicknesses (0.4, 0.7, 1.0, 1.3, and 1.6 mm; N = 60, n = 12) were produced out of each ceramic (N = 180). A spectrophotometer was used to measure the transmittance coefficient tc[%] for each wavelength within the visible light spectrum, and the total light transmittance (T%) was calculated for each specimen. Linear, exponential, and logarithmic regression curves were fitted to the results. RESULTS: The logarithmic regression curves exhibited the best correlation (R2; IPS Empress CAD LT, R2 = 0.996; IPS e.max CAD LT, R2 = 0.987; Lava Plus HT, R2 = 0.907) to the transmittance values. CONCLUSION: Within the limitations of the present study, the transmittance behavior of silicate ceramics, lithium-X-silicate ceramics, and oxide ceramics can be described by a logarithmic equation. The findings of this study therefore suggest that the optical behavior might be calculable by a mathematical approach.


Assuntos
Porcelana Dentária , Estética Dentária , Cerâmica , Desenho Assistido por Computador , Humanos , Luz , Teste de Materiais , Espectrofotometria , Propriedades de Superfície
5.
Int J Mol Sci ; 22(10)2021 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-34068386

RESUMO

(1) Background: Properties and descriptors are two forms of molecular in silico representations. Properties can be further divided into functional, e.g., catalyst or drug activity, and material, e.g., X-ray crystal data. Millions of real measured functional property records are available for drugs or drug candidates in online databases. In contrast, there is not a single database that registers a real conversion, TON or TOF data for catalysts. All of the data are molecular descriptors or material properties, which are mainly of a calculation origin. (2) Results: Here, we explain the reason for this. We reviewed the data handling and sharing problems in the design and discovery of catalyst candidates particularly, material informatics and catalyst design, structural coding, data collection and validation, infrastructure for catalyst design and the online databases for catalyst design. (3) Conclusions: Material design requires a property prediction step. This can only be achieved based on the registered real property measurement. In reality, in catalyst design and discovery, we can observe either a severe functional property deficit or even property famine.


Assuntos
Desenho de Fármacos , Nanotecnologia , Preparações Farmacêuticas/química , Preparações Farmacêuticas/metabolismo , Catálise , Bases de Dados Factuais , Teste de Materiais
6.
Zhejiang Da Xue Xue Bao Yi Xue Ban ; 50(2): 179-186, 2021 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-34137232

RESUMO

To investigate the effect of captopril on the dentin bonding durability of self-etch adhesive. Different concentrations of captopril ethanol solutions or captopril ethanol/water solutions were prepared to pretreat dentin as primer for the self-etch adhesives. The surface morphology of the dentin was observed with scanning electron microscopy (SEM). Based on the morphology analysis, the pretreatment condition was selected and two self-etch adhesives were employed to evaluate the improvement effect of the captopril pretreatment on the dentin bonding durability. : SEM showed that the pretreatment of captopril ethanol solutions and captopril ethanol/water solutions were able to remove the smear lay and partially expose collagen matrix. According to the SEM results, the pretreating condition of captopril ethanol/water solution with the pretreating time of was selected for further dentin bonding study. For Clearfil SEBOND system, the immediate bonding strength increased from to  (<0.05). After one-year aging, the bonding strength of the control group decreased markedly [(22.90±6.82) MPa, <0.05]; while the bonding strength of the captopril pretreated group kept steadily >0.05]. For Clearfil S BOND system, there was no significant difference in the immediate bonding strength between the experimental group [(4.07) MPa] and the control group[(4.11) MPa]. But after one-year aging, the bonding strength of the experimental group was higher than that of the control group <0.05]. : The pretreatment with captopril ethanol/water solution increases the dentin bonding strength of the self-etch adhesive systems and also improves the bonding durability.


Assuntos
Colagem Dentária , Adesivos Dentinários , Adesivos , Captopril , Dentina , Teste de Materiais , Microscopia Eletrônica de Varredura , Cimentos de Resina
7.
Int J Oral Maxillofac Implants ; 36(3): 451-459, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34115058

RESUMO

PURPOSE: Microcomputed tomography (micro-CT) is a relatively new modality to investigate mechanical deformations. The purpose of this study was to assess the microgap at the implant-sleeve connection of a new two-piece dental implant with a replaceable sleeve. MATERIALS AND METHODS: Implants were assembled with 25-degree angulated abutments. Micro-CT was used to assess implant-sleeve connection gaps under the following mechanical conditions: (1) unloading; (2) compressive 10,000 cyclic loading with 400 N; (3) static compressive load of 200 N or 400 N for 24 hours. RESULTS: The mean gap in the unloaded sample was 2.9 ± 0.9 µm. The mean gap difference after cyclic compressive load was 0.3 ± 0.15 µm, demonstrating a negligible effect for the cyclic loading. Under static compressive load, there was no increase in microgap size at 200 N. At 400 N, a significant (P < .05) increase was noted. While the mean values increased by 1.9 µm, the most pronounced significant increase in mean microgap was noted in the direction of force application (5.1 ± 2.14 µm), while a significant decrease in mean microgap (1.2 ± 1.47 µm) was noted on the opposite side. CONCLUSION: The mechanical behavior of the implant-sleeve connection under static and dynamic loads was found to be within the previously reported range of implant dentistry.


Assuntos
Implantes Dentários , Dente Suporte , Projeto do Implante Dentário-Pivô , Análise do Estresse Dentário , Teste de Materiais , Microtomografia por Raio-X
8.
Int J Oral Maxillofac Implants ; 36(3): 485-491, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34115062

RESUMO

PURPOSE: To evaluate the factors that could influence the fracture resistance of implant-supported posterior monolithic zirconia crowns. MATERIALS AND METHODS: Sixty zirconia molar crowns with three different occlusal thicknesses of 0.5, 1.0, and 1.5 mm (20 samples per group) were prepared for implant abutments using a CAD/CAM system. In each group, 10 crowns were luted on the abutment with resin cement (Panavia F), and the other 10 crowns were luted with resin-modified glass-ionomer cement (Ketac Cem Plus). Dynamic loading (1.2 × 106 cycles; 70 N) and thermal cycling were applied to the samples using a chewing simulator before evaluating their fracture resistance with a universal testing machine and examining their fracture type using a stereomicroscope. One-way analysis of variance (ANOVA), the Duncan test, and two-way ANOVA were used for data evaluation (α = .05). RESULTS: The occlusal thickness (P < .001) and cement type (P < .01) affected the fracture load of the monolithic zirconia crowns. The highest fracture resistance was found in 1.5-mm-thick crowns luted with resin cement (4,212 ± 501 N), and the lowest fracture resistance was found in 0.5-mm and 1-mmthick crowns luted with resin-modified glass-ionomer cement (1,198 ± 116 N and 1,197 ± 66 N). A significant difference was not found in the mean maximum fracture load between the 1.5-mm-thick crowns cemented with resin cement and glass-ionomer resin cement. CONCLUSION: Both the occlusal thickness and cement type remarkably affected the fracture resistance of the crowns, but occlusal thickness was more significant. Implant-supported posterior zirconia crowns can withstand physiologic occlusal forces even with a thickness as low as 0.5 mm. Resin luting cement is recommended for implant-supported posterior zirconia crowns with reduced occlusal thickness.


Assuntos
Implantes Dentários , Porcelana Dentária , Desenho Assistido por Computador , Coroas , Planejamento de Prótese Dentária , Análise do Estresse Dentário , Cimentos de Ionômeros de Vidro , Teste de Materiais , Cimentos de Resina , Zircônio
9.
Int J Oral Maxillofac Implants ; 36(3): 492-501, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34115063

RESUMO

PURPOSE: To evaluate the abutment removal torque and the morphologic aspects of wear in frictional Morse taper connections after axial loading with or without biofilm immersion. MATERIALS AND METHODS: Thirty sets of Morse taper implants and prosthetic abutments were divided into six groups based on the number of mechanical loading cycles and immersion in biofilm derived from human saliva: without load, without biofilm; without load, with biofilm; 100,000 cycles of load, without biofilm; 100,000 cycles of load, with biofilm; 500,000 cycles of load, without biofilm; and 500,000 cycles of load, with biofilm. Mechanical loading was applied at a force of 80 ± 15 N with a frequency of 2 Hz for 100,000 or 500,000 cycles. After removal torque evaluation, the internal surface of the implants was evaluated by scanning electron microscopy and optical profilometer. The results were statistically analyzed at a significance level of P = .05. RESULTS: Overall, the removal torque increased for samples submitted to loading (100,000 cycles of load, without biofilm = 83.8 ± 15.8 Ncm; 100,000 cycles of load, with biofilm = 160.6 ± 16.2 Ncm; 500,000 cycles of load, without biofilm = 147.0 ± 29.3 Ncm; 500,000 cycles of load, with biofilm = 154.5 ± 14.0 Ncm) compared to samples without loading (without load, without biofilm = 23.0 ± 9.4 Ncm; without load, with biofilm = 27.2 ± 7.5 Ncm). The removal torque was not different between groups that received the same number of loading cycles and varied on biofilm exposure (P > .05). However, samples immersed in biofilm showed higher values of removal torque. Surface analysis revealed that the damage on the internal surface of implants was lower in samples not submitted to cyclic mechanical loading (P < .05) independently of immersion in biofilm medium. CONCLUSION: Cyclic mechanical load on the frictional implant-abutment connection of Morse taper implants increased the removal torque of abutments. The findings of this research suggest that the presence of biofilm can potentially increase the removal torque in frictional Morse taper connections, although more studies are recommended to support this affirmation. Oral biofilm did not interfere with the presence of wear areas along the internal surface of Morse taper implants but increased the roughness values.


Assuntos
Projeto do Implante Dentário-Pivô , Implantes Dentários , Biofilmes , Dente Suporte , Análise do Estresse Dentário , Humanos , Teste de Materiais , Torque
10.
Niger J Clin Pract ; 24(6): 828-832, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34121729

RESUMO

Background: Temporary stage in crowns and bridgework plays an important role in the success and failure of the final restorations. Lack of marginal seal of the temporary restorations can lead to further complications. Recently, digital dentistry has been improved in terms of marginal integrity. Aims: The aim of this study was to evaluate and compare the marginal leakage between CAD/CAM and conventionally made Polymethyl methacrylate (PMMA) interim crowns cemented with different temporary luting cements. Materials and Methods: Sixty resin dies of a maxillary right first premolar were prepared according to the protocol of the tooth preparation for all-ceramic crown. Interim crowns were then fabricated and assigned to two main groups according to the fabrication technique (CAD/CAM technique and conventional technique). Furthermore, the samples were sub-grouped (n = 10) according to the type of the luting cements: Zinc oxide eugenol (RelyX temp E), Zinc oxide non-eugenol (RelyX temp NE), and Zinc polycarboxylate cement (pentron). The specimens were then subjected to thermocycling at 5°C and 55°CC for 30 sec and transfer time of 15 seconds for 1500 cycles. After that, the specimens were immersed in a 2% methylene blue solution for 24 hours. The cemented specimens were sectioned buccolingually and the amount of marginal leakage was evaluated under digital microscope at magnification 50x. The scores of dye penetration were recorded and analyzed using one-way ANOVA at P < 0.05 for all tests. Results: For the fabrication technique, CAD/CAM-made interim crowns had significantly better performance in terms of lower microleakage in comparison to conventionally built interim crowns (P < 0.001). Overall, Zinc Oxide non-eugenol also showed significantly least microleakage as a luting cement then Zinc Oxide Eugenol and the most microleakage was found with Zinc Polycarboxylate regardless of the fabrication method. Conclusion: Interim crowns fabricated by CAD-CAM system are better suited for temporization. Zinc-oxide non-eugenol cements showed the least amount of microleakage in both types of crown.


Assuntos
Desenho Assistido por Computador , Coroas , Cimentação , Cimentos Dentários , Cimentos de Ionômeros de Vidro , Teste de Materiais , Cimentos de Resina , Preparo do Dente
11.
J Adhes Dent ; 23(3): 233-242, 2021 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-34060303

RESUMO

PURPOSE: To investigate the effects of several etching products prior to the application of a one-step self-etch adhesive (1-SEA) or two-step self-etch adhesive (2-SEA) on enamel by microshear bond strength (µSBS) testing and observation of the adhesive-enamel interface. MATERIALS AND METHODS: Ground human enamel surfaces were randomly assigned to one of eight groups according to the combination of surface treatments (either no conditioner [NC], ME [Multi Etchant], EC [Enamel Conditioner], or KE [K-etchant Gel]) and adhesive (ADU [Adhese Universal] or SE2 [Clearfil SE Bond 2]). All groups were further divided into two subgroups: 0 or 10,000 thermal cycles (TC). Then, the µSBS test was performed. The adhesive-enamel interface after acid-base challenge and the surface structure after conditioner application were also observed. RESULTS: With 10,000 TCs, there was no statistically significant difference between ME-ADU and NC-ADU. On the other hand, the µSBS of EC-ADU or KE-ADU was significantly higher than that of NC-ADU, while that of ME-SE2 was significantly lower than NC-SE2. There was no significant difference between EC-SE2, NC-SE2, and KE-SE2. Formation of an acid-base resistance zone (ABRZ) was confirmed in all groups. However, funnel-shaped erosion, which indicates interfacial defects, was observed in the NC-ADU, ME-ADU, and ME-SE2 groups. CONCLUSION: For enamel bonding, application of EC or KE prior to ADU increased the bond strength and created a stable adhesive-enamel interface. On the other hand, SE2 also had stable shear bond strength and interface without the use of conditioners. However, ME decreased the bonding performance of SE2.


Assuntos
Condicionamento Ácido do Dente , Colagem Dentária , Cimentos Dentários , Esmalte Dentário , Humanos , Teste de Materiais
12.
J Adhes Dent ; 23(3): 255-265, 2021 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-34060305

RESUMO

PURPOSE: To evaluate the effect of different surface modification methods on the microtensile bond strength (µTBS) of four resin-matrix CAD/CAM ceramics after artificial aging. MATERIALS AND METHODS: Specimens of four CAD/CAM materials (Shofu Block HC, Lava Ultimate, Brilliant Crios, and Vita Enamic) were prepared and divided into four groups. Each group received one of the following treatments: group 1 (INT): no surface modification; group 2: sandblasting with 29-µm Al2O3 particles (SB); group 3: hydrofluoric acid etching (9%) + silane (HF+Si); group 4: sandblasting with 30-µm particles of the CoJet system (CJ). The specimens of each group were luted together in pairs using resin cement (RelyX Ultimate). After one week of water storage (37°C), the sandwich specimens were sectioned into rectangular microspecimens and half of them were immediately subjected to µTBS testing, while the other half was tested after six months. Data were statistically analyzed using FFANOVA including the factors of material, treatment, and storage time, with α = 0.05. RESULTS: After one week, the lowest µTBS was observed for INT, while the highest was found for either mechanical (SB and CJ) or chemical (HF+Si) treatments (p < 0.05). After six months, a significant decrease in µTBS was observed depending on treatment (p < 0.05), while artificial aging significantly influenced the µTBS of all experimental groups (p < 0.05). During the two storage periods, the failure type was mainly interfacial and was associated with the type of surface modification. CONCLUSION: After artificial aging, the µTBS appeared to depend on srface modification, while the parameter "material" did not influence the results. Consequently, adhesive strategies should be oriented towards surface modification techniques.


Assuntos
Colagem Dentária , Cimentos de Resina , Cerâmica , Teste de Materiais , Propriedades de Superfície , Resistência à Tração
13.
J Adhes Dent ; 23(3): 267-275, 2021 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-34060306

RESUMO

PURPOSE: To compare the shear bond strength of composite cement to lithium-disilicate glass-ceramic coated zirconia vs to alumina air-abraded zirconia and to analyze the residual stresses on both of lithium-disilicate glass-ceramic coated zirconia vs alumina air-abraded zirconia specimens. MATERIALS AND METHODS: One hundred eighty zirconia disks (diameters 10 mm and 5 mm, 4.5 mm thick) were divided into two groups: lithium-disilicate glass-ceramic coating followed by hydrofluoric acid etching and Monobond N Primer (LiDi) or alumina air-abrasion (AA). For each group, two different sizes of identically pre-treated zirconia specimens were bonded with Multilink Speed Cement. A total of 90 specimens were stored in distilled water at 37°C for 24 h and then assigned to three subgroups (n = 15/test group): 1. short-term test; 2. thermocycling for 5000 cycles; 3. thermocycling for 10,000 cycles. Bond strength was tested in shear mode and results were analyzed using two-way ANOVA, followed by one-way ANOVA and Tukey's HSD (α = 0.05). Failure mode and surfaces were analyzed with optical and scanning electron microscopy. X-ray diffraction was used to analyze t-m phase transformation and residual stresses on mechanically pre-treated LiDi and AA surfaces. RESULTS: The LiDi groups recorded higher mean bond strength than AA groups after thermocycling (p < 0.05). Thermocycling did not affect the bond strength of either LiDi or AA groups (p > 0.05). Most of specimens in AA groups exhibited mixed failure. Alumina air-abraded surfaces exhibited higher residual compressive stresses than did surfaces with a lithium-disilicate glass-ceramic coating. CONCLUSION: Following thermocycling, composite-zirconia bond strength of specimens with a lithium-disilicate glass-ceramic coating was greater than that of alumina air-abraded specimens.


Assuntos
Óxido de Alumínio , Colagem Dentária , Lítio , Teste de Materiais , Cimentos de Resina , Propriedades de Superfície , Zircônio
14.
J Pak Med Assoc ; 71(6): 1648-1654, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34111090

RESUMO

OBJECTIVE: To explain the success and failure of dental implant diameter on the efficiency of fatigue. METHODS: The systematic review was conducted using PubMed and Cochrane databases for Original Articles published in the English language from 1999 to 2019. Outcomes were evaluated to determine perceptions regarding the role of dental implant diameter in influencing the implant's fatigue performance. Data was analysed using SPSS 22. RESULTS: Of the 263 abstracts retrieved, 53(20%) were reviewed. Of them, 14(26.4%) were included; 9(64.3%) systematic reviews, and 5(35.7%) studies. The implant diameter could be categorised into wide diameter (5-6mm), regular diameter (3.75-4mm), and small/narrow diameter (3-3.4mm). The narrow diameter implants are indicated through thin alveolar ridges and mesiodistal spaces (<7mm). The implants with narrow diameter would offer greater risk of fatigue failure for clinical situations with significant functional loading (p<0.05). No significant differences were found either in success or failure of dental implant diameter on fatigue efficiency at 1-year and 3-year follow-ups (p>0.05). CONCLUSIONS: The technical complication of dental implant included abutment screw loosening or fracture, abutment and superstructure fracture, and implant body fracture. The review mainly focussed on the impact of dental implant diameter on the efficiency of fatigue and reviewed a significant impact of dental implant diameter on the fatigue efficiency.


Assuntos
Implantes Dentários , Humanos , Teste de Materiais
15.
Nat Commun ; 12(1): 3303, 2021 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-34083518

RESUMO

Peri-implant infection is one of the biggest threats to the success of dental implant. Existing coatings on titanium surfaces exhibit rapid decrease in antibacterial efficacy, which is difficult to promisingly prevent peri-implant infection. Herein, we report an N-halamine polymeric coating on titanium surface that simultaneously has long-lasting renewable antibacterial efficacy with good stability and biocompatibility. Our coating is powerfully biocidal against both main pathogenic bacteria of peri-implant infection and complex bacteria from peri-implantitis patients. More importantly, its antibacterial efficacy can persist for a long term (e.g., 12~16 weeks) in vitro, in animal model, and even in human oral cavity, which generally covers the whole formation process of osseointegrated interface. Furthermore, after consumption, it can regain its antibacterial ability by facile rechlorination, highlighting a valuable concept of renewable antibacterial coating in dental implant. These findings indicate an appealing application prospect for prevention and treatment of peri-implant infection.


Assuntos
Antibacterianos/farmacologia , Materiais Revestidos Biocompatíveis/farmacologia , Peri-Implantite/prevenção & controle , Peri-Implantite/terapia , Titânio/farmacologia , Aminas/administração & dosagem , Aminas/química , Aminas/farmacologia , Animais , Antibacterianos/administração & dosagem , Antibacterianos/química , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Materiais Revestidos Biocompatíveis/administração & dosagem , Materiais Revestidos Biocompatíveis/química , Implantes Dentários , Estabilidade de Medicamentos , Humanos , Técnicas In Vitro , Masculino , Teste de Materiais , Osseointegração/efeitos dos fármacos , Peri-Implantite/microbiologia , Porosidade , Coelhos , Propriedades de Superfície , Titânio/administração & dosagem , Titânio/química
16.
Mater Sci Eng C Mater Biol Appl ; 126: 112105, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34082929

RESUMO

AIM: Our study aimed to measure (1) the flexural strength, (2) shear bond strength to dentin, (3) pH, and (4) calcium (Ca) release of a series of innovative resin-modified calcium-silicate pulp-capping cements (Rm-CSCs). Using an ex-vivo human vital tooth-culture model, we additionally assessed (5) their pulp-healing initiation when brought in direct contact with human dental pulp tissue. METHODOLOGY: Three experimental Rm-CSCs, being referred to 'Exp_HEAA', 'Exp_GDM' and 'Exp_HEAA/GDM', contained either 20 wt% N-(2-hydroxyethyl) acrylamide (HEAA), 20 wt% glycerol dimethacrylate (GDM) or 10 wt% HEAA plus 10 wt% GDM, added to a common base composition consisting of 25 wt% urethane dimethacrylate (UDMA), 10 wt% 4-methacryloxyethyl trimellitate anhydride (4-MET), and 5 wt% N,N'-{[(2-acrylamido-2-[(3-acrylamidopropoxy)methyl] propane-1,3-diyl)bis(oxy)]bis-(propane-1,3-diyl)}diacrylamide (FAM-401). As Ca source and radiopacifier, 37 wt% tricalcium silicate powder (TCS) and 3 wt% zirconium oxide (ZrO 2) were respectively added. RESULTS: All three experimental Rm-CSCs revealed a significantly higher flexural strength and shear bond strength to dentin (p < 0.05) than the commercial reference Rm-CSC TheraCal LC (Bisco). Exp_HEAA presented with a significantly higher Ca release and pH at 24 h compared with the other Rm-CSCs (p < 0.05). At 1 week, the Ca release and pH of Exp_HEAA and Exp_HEAA/GDM was significantly higher than those of Exp_GDM and TheraCal LC (p < 0.05). Using the ex-vivo human vital tooth culture model, Exp_HEAA revealed pulp-healing initiation capacity as documented by nestin and collagen-I expression. CONCLUSIONS: Depending on the formulation, the innovative Rm-CSCs performed favorably for primary properties of relevance regarding pulp capping, this more specifically in terms of flexural strength, bond strength to dentin, as well as alkaline pH and Ca release. However, only Exp_HEAA revealed pulp-healing initiation in direct contact with human dental pulp tissue in the ex-vivo human vital tooth-culture model. This promising outcome for Exp_HEAA should be attributed to the combined use of (1) a novel hydrophilic acrylamide monomer, enabling sufficient polymerization while maintaining adequate hydrophilicity, with (2) the functional monomer 4-MET, possessing chemical bonding potential to dentin, and (3) tricalcium silicate powder to achieve an alkaline pH and to release Ca in a sufficient and controlled way.


Assuntos
Cálcio , Cimento de Silicato , Acrilamida , Compostos de Cálcio , Humanos , Teste de Materiais , Silicatos , Engenharia Tecidual
17.
Ann Palliat Med ; 10(5): 5462-5473, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-34107709

RESUMO

BACKGROUND: To evaluate the clinical performance of universal adhesives in etch-and-rinse or self-etch application modes through meta-analysis. METHODS: A literature search was performed by two reviewers in the PubMed, Cochrane Library, and Embase databases (from January 2000 to March 2020). A total of 2,516 non-replicated records were identified and filtered. Studies that evaluated the clinical performance of universal adhesives using etch-and-rinse or self-etch mode were included. RevMan 5.3.5 (Cochrane, London, UK) was used to perform the meta-analysis. RESULTS: A total of 13 studies were included in the meta-analysis. The retention rates were higher in etch-and-rinse groups compared with self-etch groups [odds ratio (OR) =0.35, 95% confidence interval (CI): 0.18-0.71, P=0.003]. The etch-and-rinse approach also had better performance in marginal adaptation (OR =0.49, 95% CI: 0.36-0.67, P<0.001) and marginal staining (OR =0.49, 95% CI: 0.36-0.66, P<0.001). The current data showed a very low incidence rate of secondary caries or postoperative sensitivity, and there were no significant differences in the incidence rates between the etch-and-rinse groups and self-etch groups. DISCUSSION: The current evidence shows that, compared with self-etch approach, the etch-and-rinse approach for universal adhesives provides improved clinical outcomes in terms of retention rates, marginal adaptation, and marginal staining.


Assuntos
Adesivos , Adesivos Dentinários , Humanos , Londres , Teste de Materiais , Cimentos de Resina
18.
Shanghai Kou Qiang Yi Xue ; 30(2): 120-123, 2021 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-34109347

RESUMO

PURPOSE: To explore the advantages of fiber reinforced composites veneer in repairing discolorated and defective anterior teeth. METHODS: Twenty porcelain veneers and 20 fiber reinforced composites veneers specimens of 2 cm long, 2 cm wide and 1 mm in thickness, with a longitudinal cross section of 45° incline were made. Another 40 fiber reinforced composites specimens of the same shape were used for comparison. After polishing and acid treatment of all the specimens according to clinical routine, resin cement was used for bonding the porcelain cover with resin veneers slope, and the conjunct specimens were soaked in 40 ℃ warm water for 24 h and drying; then the two groups of specimens were put were put on the pressure testing platform of the universal testing machine, with 1 mm/min testing pressure, and 1 cm2 square head was contacted on the surface of the bonding interface. Computer was used to record the fracture process of the two groups of specimens and the maximum compressive strength of bonding interface automatically. The compressive strength of the bonding interface under the same conditions was evaluated. SPSS 12.0 software package was used for statistical analysis. RESULTS: The compressive strength of the bonding interface between fiber reinforced composites was significantly higher than that between porcelain and fiber reinforced composites(P<0.05). CONCLUSIONS: Compared with porcelain veneers that can not be repaired when damaged in the anterior teeth, high-strength fiber resin veneers can partially be repaired with the same material, which has obvious advantages.


Assuntos
Colagem Dentária , Facetas Dentárias , Resinas Compostas , Porcelana Dentária , Análise do Estresse Dentário , Estética Dentária , Teste de Materiais , Cimentos de Resina
19.
Shanghai Kou Qiang Yi Xue ; 30(2): 191-195, 2021 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-34109361

RESUMO

PURPOSE: To investigate the clinical performance of chairside monolithic lithium disilicate glass-ceramics computer-aided design(CAD)-computer aided manufacturing(CAM) crowns, and to analyze the influencing factors of cumulative survival rate. METHODS: Two hundred and fourteen patients who had chairside posterior lithium disilicate glass-ceramic CAD-CAM crowns in Peking University Shenzhen Hospital from March 2015 to March 2017 were enrolled. The crown preparations were milled using Cerec Omnicam system. The clinical and esthetic effects of the crowns were analyzed at 3, 6, 12, 24, and 36 months. The cumulative survival rate of crowns was calculated, and the effects of gender, age, pulp condition, tooth position and adhesive type on the cumulative survival rate were analyzed. SPSS 20.0 software package was used for statistical analysis. RESULTS: After a 36-month follow-up, the failed crowns were mainly caused by marginal integrity, crown fracture and loss of retention. During the observation period of 3, 6, 12, 24 and 36 months, the scores of color, shape, quality of proximal contact, and chewing ability were greater than 9. The cumulative survival rates were 100.00%, 96.17%, 94.89%, 92.77% and 91.06% at 3, 6, 12, 24 and 36 months, respectively. The cumulative survival rate had no significant difference among different gender, age, and dental pulp status(P>0.05). CONCLUSIONS: Chairside monolithic lithium disilicate glass-ceramic CAD-CAM crowns have a high 3-year cumulative survival rate and good esthetic outcome, which is not affected by gender, age, and pulp status with high clinical value.


Assuntos
Planejamento de Prótese Dentária , Estética Dentária , Cerâmica , Desenho Assistido por Computador , Coroas , Porcelana Dentária , Humanos , Teste de Materiais
20.
Braz Oral Res ; 35: e062, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34133579

RESUMO

This in vitro study evaluated the impact of TiO2 nanotubes (n-TiO2) incorporated into glass ionomer cement (GIC) on Streptococcus mutans (S. mutans) characteristics at cellular and molecular levels. n-TiO2, synthesized by the alkaline method (20 nm in size), was added to Ketac Molar EasyMix® at 0%, 3%, 5%, and 7% by weight. S. mutans strains were cultured on GIC disks with addition or not of n-TiO2 for 1, 3, and 7 days and the following parameters were assessed: inhibition halo (mm) (n=3/group); cell viability (live/dead) (n=5/group); cell morphology (SEM) (n=3/group); and gene expression by real-time PCR (vicR, covR, gtfB, gtfC, and gtfD) (n=6/group). The data were analyzed by the Kruskal-Wallis test, repeated-measures ANOVA or two-way ANOVA, and Tukey's and Dunn's post-hoc tests (α=0.05). The agar diffusion test showed a higher antibacterial property for 5% n-TiO2 compared with 3% and 7% (p<0.05) with no effect of time (1, 3, and 7 days). The cell number was significantly affected by all n-TiO2 groups, while viability was mostly affected by 3% and 5% n-TiO2, which also affected cell morphology and organization. Real-time PCR demonstrated that n-TiO2 reduced the expression of covR when compared with GIC with no n-TiO2 (p<0.05), with no effect of time, except for 3% n-TiO2 on vicR expression. Within-group and between-group analyses revealed n-TiO2 did not affect mRNA levels of gtfB, gtfC, and gtfD (p>0.05). Incorporation of n-TiO2 at 3% and 5% potentially affected S. mutans viability and the expression of key genes for bacterial survival and growth, improving the anticariogenic properties of GIC.


Assuntos
Nanotubos , Streptococcus mutans , Cimentos de Ionômeros de Vidro/farmacologia , Teste de Materiais , Titânio , Virulência
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