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1.
Dent Mater J ; 43(3): 477-484, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38719582

RESUMO

We aimed to evaluate the antibacterial activity of phytochemicals with or without an experimental fluoride varnish against Porphyromonas gingivalis. Five phytochemicals, chrysophanol (CHR), emodin (EMO), anthrarufin (ANT), bavachalcone (BCC), and isobavachromene (IBC), were tested using agar diffusion, minimal inhibition concentration (MIC), and minimum bacterial concentration (MBC) assays. We also assessed the cell viability and cytotoxicity of phytochemicals. All phytochemicals showed clear inhibition zones in the agar diffusion test. The inhibition zones of all phytochemical-containing fluoride varnishes were similar to or larger than that of the positive control, excluding that of 1 mM EMO. With or without the fluoride varnish, BCC exhibited the lowest MIC and MBC levels. Cell viability was high in the presence of all phytochemicals except 200 µM EMO. In conclusion, BCC was most effective as a phytochemical alone, while all phytochemical-containing fluoride varnishes inhibited P. gingivalis growth without cytotoxicity.


Assuntos
Antibacterianos , Sobrevivência Celular , Testes de Sensibilidade Microbiana , Doenças Periodontais , Compostos Fitoquímicos , Porphyromonas gingivalis , Porphyromonas gingivalis/efeitos dos fármacos , Antibacterianos/farmacologia , Compostos Fitoquímicos/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Doenças Periodontais/prevenção & controle , Doenças Periodontais/microbiologia , Fluoretos Tópicos/farmacologia , Humanos
2.
Dent Mater J ; 43(2): 320-327, 2024 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-38382939

RESUMO

We aimed to determine whether adhesive components could increase the release time of effective fluoride concentration from an experimental fluoride varnish applied to bovine teeth. An experimental fluoride varnish containing 5% sodium fluoride (EX1) was prepared and combined with 35% hydroxyethyl methacrylate (HEMA) (EX2), 5% glutaraldehyde (EX3), or 35% HEMA/5% glutaraldehyde mixture (EX4). Two commercially available fluoride varnishes were used for comparison. Each group was applied to bovine incisors, and the fluoride release and pH were monitored for 30 days. Cell viability analysis, scanning electron microscopy, and energy-dispersive spectroscopy were performed. EX4 released the highest and most effective concentration of fluoride for the longest period and reached neutral pH at the earliest; the release was maintained for up to 30 days without cytotoxicity. In conclusion, EX4 is considered to be the most effective varnish to prevent dental caries.


Assuntos
Cárie Dentária , Fluoretos , Metacrilatos , Animais , Bovinos , Fluoretos/farmacologia , Fluoretos Tópicos/farmacologia , Fluoretos Tópicos/química , Cariostáticos/farmacologia , Cariostáticos/química , Cárie Dentária/prevenção & controle , Glutaral , Fluoreto de Sódio/farmacologia , Fluoreto de Sódio/química
3.
Materials (Basel) ; 16(18)2023 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-37763402

RESUMO

Several calcium silicate cement (CSC) types with improved handling properties have been developed lately for root-end filling applications. While sealing ability is important, a high biocompatibility and antimicrobial effects are critical. This study aimed to conduct a comparative evaluation of the antimicrobial efficacy and sustained antibacterial effectiveness against Enterococcus faecalis (E. faecalis) of commercially available CSCs mixed with distilled water (DW) and chlorhexidine (CHX). Various products, viz., ProRoot mixed with DW (PRW) or with CHX (PRC), Endocem mixed with DW (EW) or with CHX (EC), and Endocem premixed (EP) syringe type, were used. While antibacterial activity against E. faecalis was evaluated using a direct contact method, the specimens were stored in a shaking incubator for 30 d for antibacterial sustainability. The cytotoxicity was evaluated using a cell counting kit-8 assay in human periodontal ligament stem cells. The antibacterial activities of EP, EW, and EC were greater than those of PRC and PRW (p < 0.05). The antibacterial sustainability of EP was the highest without cytotoxicity for up to 30 days (p < 0.05). In conclusion, the pre-mixed injectable type EP was most effective in terms of antibacterial activity and sustained antibacterial effectiveness without cytotoxicity.

4.
Nanomaterials (Basel) ; 13(8)2023 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-37110962

RESUMO

Photobiomodulation (PBM) therapy is known to have the potential to improve bone regeneration after implant surgery. However, the combinatory effect of the nanotextured implant and PBM therapy on osseointegration has not yet been proved. This study evaluated the photobiomodulation-based synergistic effects of Pt-coated titania nanotubes (Pt-TiO2 NT) and 850 nm near-infrared (NIR) light on osteogenic performance in vitro and in vivo. The FE-SEM and the diffuse UV-Vis-NIR spectrophotometer were used to perform the surface characterization. The live-dead, MTT, ALP, and AR assays were tested to perform in vitro tests. The removal torque testing, the 3D-micro CT, and the histological analysis were used to conduct in vivo tests. The live-dead and MTT assay resulted in Pt-TiO2 NTs being biocompatible. The ALP activity and AR assays demonstrated that the combination of Pt-TiO2 NT and NIR irradiation significantly enhanced osteogenic functionality (p < 0.05). The results of in vivo test, employing the removal torque testing, the 3D-micro CT, and histological analysis, showed overall improved outcomes; however, no significant difference was observed between the control and experimental groups (p > 0.05). Therefore, we confirmed the possibility of the combination of Pt-TiO2 NT and NIR light as a promising technology for implant surgery in dentistry.

5.
Dent Mater J ; 42(2): 273-281, 2023 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-36696986

RESUMO

The aims of this study were to estimate the machinability and machining accuracy of polymer-based CAM blocks using the merlon fracture test model specified in ISO 18675: 2022. Three hybrid disc blanks (MazicDuro, HC Disk, and Enamic) and three polymethyl methacrylate (PMMA) disc blanks (PMMA Disk, PMMA Block, and MazicTemp Hybrid) were tested in this study. The machinability was evaluated by assigning scores according to the fracture range of merlons with areas divided by ten vertical planes. The machining accuracy was evaluated by superimposing methods via CAD reference data and CAD specimen data. Within the limits of this study, a thickness of 0.3 mm is recommended for the clinical application of polymer-based CAD/CAM blocks in dental restorations that require superior machinability and accuracy. In addition, the machinability and machining accuracy tests of polymer-based CAM blocks are expected to provide guidelines for preparing accurate dental restorations.


Assuntos
Polímeros , Polimetil Metacrilato , Teste de Materiais , Cerâmica , Desenho Assistido por Computador , Propriedades de Superfície
6.
Materials (Basel) ; 15(15)2022 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-35955331

RESUMO

This study was aimed at preparing zirconia samples via additive manufacturing (AM) and subtractive manufacturing (SM) and testing the following aspects: (1) the manufacturing accuracy of the zirconia samples and (2) the bond strength of porcelain to zirconia to evaluate the applicability of the zirconia fabricated by AM in dental clinics. We used three milling machines for SM (AR, K5, and UP) and a 3D printer for AM (AO). The manufacturing accuracy of the zirconia specimen in the internal and marginal areas was evaluated by superimposing techniques to calculate the root mean square (RMS) values. The bond strengths of porcelain to zirconia prepared via SM and AM were measured using a universal testing machine. The internal and marginal RMS values of the zirconia prepared by AM (AO) were within the range of those of the zirconia prepared by SM (AR, K5, and UP). Moreover, the bond strength value of the zirconia prepared by AM (35.12 ± 4.09 MPa) was significantly higher than that of the zirconia prepared by SM (30.26 ± 5.20 MPa). Therefore, AM technology has significant potential for applications in dentistry.

7.
Medicina (Kaunas) ; 58(4)2022 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-35454345

RESUMO

Background and Objective: There is increasing interest in preventing periodontitis using natural products. The purpose of this study was to investigate the effect of Colocasia antiquorum var. esculenta (CA) varnish on the oral microbiome and alveolar bone loss in a mouse periodontitis model. Materials and Methods: Antibacterial activity against Porphyromonas gingivalis (P. gingivalis) ATCC 53978 and cell cytotoxicity using CCK-8 on L929 cells were measured. Balb/c mice were assigned into five groups (negative control, positive control, CA in drinking water, varnish, and CA varnish). P. gingivalis was administered to the mice by oral gavage three times. After sacrifice, the oral microbiome and the levels of the inflammatory cytokine IL-1ß and matrix metalloproteinase-9 were analyzed. Alveolar bone loss was measured using micro-computed tomography. Results: CA extract showed an antibacterial effect against P. gingivalis (p < 0.05) and showed no cytotoxicity at that concentration (p > 0.05). Although alpha diversity of the oral microbiome did not statistically differ between the groups (p > 0.05), the relative abundance of dominant bacteria tended to be different between the groups. The inflammatory cytokine IL-1ß was reduced in the CA varnish group (p < 0.05), and no difference was observed in MMP-9 expression and alveolar bone loss (p > 0.05). Conclusions: CA varnish did not affect the overall microflora and exhibited an anti-inflammatory effect, suggesting that it is possibility a suitable candidate for improving periodontitis.


Assuntos
Perda do Osso Alveolar , Colocasia , Microbiota , Periodontite , Perda do Osso Alveolar/tratamento farmacológico , Perda do Osso Alveolar/prevenção & controle , Animais , Antibacterianos , Citocinas/metabolismo , Modelos Animais de Doenças , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Periodontite/tratamento farmacológico , Extratos Vegetais/metabolismo , Extratos Vegetais/farmacologia , Extratos Vegetais/uso terapêutico , Porphyromonas gingivalis/metabolismo , Microtomografia por Raio-X
8.
Dent Mater J ; 41(2): 323-332, 2022 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-35095043

RESUMO

This study evaluated the shear bond strengths of various types of resin cements between three types of adherends (composite resin, metal, and ceramic) and bovine teeth with and without thermocycling. A conventional resin cement (Variolink N), two adhesive resin cements (PANAVIA F 2.0, Multilink N), and three self-adhesive resin cements (MAXCEM ELITE, Rely X Unicem 2, Speed CEM) were used. The adherends were cemented on the superficial dentin of bovine incisors using each resin cement. Herein, 10 specimens from each group were thermocycled 5,000 times, and the other 10 were stored without thermocycling. With the resin and ceramic adherends, the shear bond strengths of Rely X Unicem 2 were significantly higher than those of the other resin cements both with and without thermocycling (p<0.05). With the metal adherend, the shear bond strengths were not significantly different among the cement groups, except MAXCEM ELITE, which showed the lowest strength.


Assuntos
Colagem Dentária , Cimentos de Resina , Animais , Bovinos , Cerâmica/química , Materiais Dentários/química , Análise do Estresse Dentário , Dentina , Teste de Materiais , Cimentos de Resina/química , Resistência ao Cisalhamento
9.
Materials (Basel) ; 14(20)2021 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-34683564

RESUMO

The visible light reactions of noble metal-based photocatalysts have been increasingly utilized to investigate their antibacterial activities. Furthermore, the photoreactions at various visible light wavelengths for specific combinations of titania nanotubes and noble metal nanoparticles have been found to promote osteogenic functionality. In this investigation, a novel multi-coating combination of noble metals (gold and platinum) on titania nanotubes was assessed using plasmonic photocatalysis and low-level laser therapy at 470 and 600 nm. The results showed that this coating on the nanotubes promoted antibacterial activity and osteogenic functionality. The order in which the gold and platinum coatings were layered onto the titania nanotubes strongly affected the osteogenic performance of the human mesenchymal stem cells. These results have identified a new approach for the development of efficient novel combinations of noble metal nanoparticles and titania nanotubes with visible light responses, sustainable antimicrobial activity, and osteogenic functionality.

10.
Medicina (Kaunas) ; 57(10)2021 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-34684091

RESUMO

Background and Objectives: Periodontal disease is a chronic inflammatory disease in which gradual destruction of tissues around teeth is caused by plaque formed by pathogenic bacteria. The purpose of this study was to evaluate the potential of 75% ethanol extract of Colocasia antiquorum var. esculenta (CA) as a prophylactic and improvement agent for periodontal disease in vitro and in vivo. Materials and Methods: The antimicrobial efficacy of CA against Porphyromonas gingivalis (P. gingivalis, ATCC 33277) was evaluated using minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) test, and cytotoxicity was confirmed by CCK-8 assay. For the in vivo study, P. gingivalis was applied by oral gavage to BALB/c mice. Forty-two days after the first inoculation of P. gingivalis, intraoral swabs were taken for microbiome analysis, and the mice were sacrificed to evaluate the alveolar bone loss. Results: The MIC of CA against P. gingivalis was 31.3 µg/mL, the MBC was 62.5 µg/mL, with no cytotoxicity. The diversity of the oral microbiome decreased in the positive control group, while those of the VA (varnish) and VCA (varnish added with CA) groups increased as much as in the negative control group, although the alveolar bone loss was not induced in the mouse model. Conclusions: CA showed antibacterial effects in vitro, and the VA and VCA groups exhibited increased diversity in the oral microbiome, suggesting that CA has potential for improving periodontal disease.


Assuntos
Colocasia , Doenças Periodontais , Animais , Camundongos , Camundongos Endogâmicos BALB C , Doenças Periodontais/tratamento farmacológico , Extratos Vegetais/farmacologia , Extratos Vegetais/uso terapêutico , Porphyromonas gingivalis
11.
Medicina (Kaunas) ; 57(7)2021 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-34206271

RESUMO

Background and Objectives:Asplenium incisum, a natural plant, is known to possess numerous pharmacological and biochemical properties. However, the inhibitory effect of A. incisum against Porphyromonas gingivalis and other factors related to periodontal disease have not yet been demonstrated. This study aimed to investigate the potential of A. incisum extract as a phytotherapeutic candidate for improving periodontal diseases by assessing its antibacterial, anti-inflammatory, and anti-osteoclastogenic activities. Materials and Methods: The inhibition of proliferation of P. gingivalis by A. incisum and the sustainability of its antibacterial activity were evaluated in this study. The production of inflammatory cytokines (tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6)) and nitric oxide (NO) from lipopolysaccharide-stimulated RAW 264.7 cells was assessed using an enzyme-linked immunosorbent assay. To identify the anti-osteoclastogenic activity, tartrate-resistant acid phosphatase (TRAP) staining and TRAP activity analyses were performed on bone marrow macrophages. Results: The proliferation of P. gingivalis was significantly inhibited by A. incisum (p < 0.001), and the antibacterial activity was sustained for up to 3 days. A. incisum showed anti-inflammatory activities by significantly decreasing the release of TNF-α, IL-6 (p < 0.05), and NO (p < 0.01). In addition, A. incisum significantly suppressed TRAP-positive cells and TRAP activity (at 30 µg/mL, p < 0.01) without causing any cytotoxicity (p > 0.05). Conclusions:A. incisum showed antibacterial, anti-inflammatory, and anti-osteoclastogenic activities, suggesting it has strong therapeutic potential against periodontal diseases.


Assuntos
Osteoclastos , Osteogênese , Citocinas , Humanos , Inflamação/tratamento farmacológico , Porphyromonas gingivalis , Fator de Necrose Tumoral alfa
12.
Dent Mater J ; 39(6): 1096-1102, 2020 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-32999262

RESUMO

This study aimed to investigate the inhibitory effects of Colocasia antiquorum var. esculenta (CA) on Porphyromonas gingivalis (P. gingivalis) growth, inflammation, and osteoclastogenesis. CA was effective in inhibiting the growth of P. gingivalis when applied together with an experimental fluoride varnish. CA also significantly decreased the release of interleukin-6, tumor necrosis factor-α, and nitric oxide from lipopolysaccharide-induced RAW 264.7 cells. No significant differences in viability were noted between the cells treated with CA and the controls. In addition, CA significantly attenuated osteoclast differentiation on bone marrow macrophages. In conclusion, CA inhibited the growth of P. gingivalis and showed anti-inflammatory and anti-osteoclastogenic effects. Therefore, CA may have the potential to act as a novel natural agent for preventing periodontitis.


Assuntos
Colocasia , Doenças Periodontais , Antibacterianos/farmacologia , Anti-Inflamatórios/farmacologia , Humanos , Osteogênese , Porphyromonas gingivalis
13.
Materials (Basel) ; 13(17)2020 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-32842504

RESUMO

This study aimed at evaluating the visible light mediated antimicrobial and osteogenic applications of noble metal, such as gold (Au) and platinum (Pt) coated titania (TiO2) nanotubes (NTs). In this study, the Au and Pt nanoparticles (NPs) were deposited on anodized 100 nm TiO2 NTs by ion plasma sputtering. The Au and Pt NPs were mainly deposited on the top surface layer of TiO2 NTs and showed light absorbance peaks around the 470 and 600 nm visible light region used in this study, as seen from the surface characterization. From the results of antibacterial activity test, Au and Pt NPs that were deposited on TiO2 NTs showed excellent antibacterial activity under 470 nm visible light irradiation due to the plasmonic photocatalysis based on the localized surface plasmon resonance effect of the Au and Pt NPs. In addition, alkaline phosphate activity test and quantitative real-time PCR assay of osteogenic related genes resulted that these NPs promoted the osteogenic functionality of human mesenchymal stem cells (hMSCs) under 600 nm visible light irradiation, because of the synergic effect of the photothermal scattering of noble metal nanoparticles and visible light low-level laser therapy (LLLT). Therefore, the combination of noble metal coated TiO2 NTs and visible light irradiation would be expected to perform permanent antibacterial activity without the need of an antibacterial agent besides promoting osteogenic functionality.

14.
Dent Mater J ; 39(4): 690-695, 2020 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-32522914

RESUMO

We investigated the inhibitory effect of antibacterial agents mixed with experimental fluoride varnish (EFV) on Streptococcus mutans. The antibacterial agents used were (1 and 10) mM of xanthorrhizol, bakuchiol, bavachalcone, isobavachromene, and bavachromene. Agar diffusion tests were performed on S. mutans (1.1×1010 CFU/mL), using antibacterial agents without and with EFV. Bavachalcone showed the highest inhibition zone without and with EFV at both (1 and 10) mM (p<0.05). All EFV with antibacterial agents showed greater inhibition and semi-inhibition zones than EFV alone (p<0.05). The cell viability of each antibacterial agent was not significantly different from the vehicle controls (p>0.05), except xanthorrhizol and bakuchiol at 1 mM. All antibacterial agents were effective, while antibacterial agents with EFV co-formulations were more effective than EFV alone. Bavachalcone was the most effective agent against S. mutans, indicating its potential usefulness with fluoride varnish in preventing dental caries.


Assuntos
Cárie Dentária , Streptococcus mutans , Antibacterianos , Fluoretos , Humanos
15.
J Tissue Eng ; 9: 2041731418790315, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30083309

RESUMO

The infection control of implants is one of the hot issues in the field of medicine and dentistry. In this study, we prepared gold nanorod-sputtered titania nanotubes on titanium surface, which is the main component of implant material, and aimed to estimate the remote-controlled tetracycline release and resulting antibacterial effects of gold nanorod-sputtered titania nanotubes using near-infrared laser irradiation. Gold nanorods prepared by ion plasma sputtering (aspect ratio = 1:3) showed optical properties like those of chemically synthesized gold nanorods, exhibiting photothermal effects in the near-infrared region, as demonstrated using field-emission scanning electron microscopy, transmission electron microscopy, and diffuse ultraviolet-visible-near-infrared spectrophotometry. In addition, a 2 wt% tetracycline/polycaprolactone mixture was found to be the most suitable experimental group to demonstrate the biological compatibilities and antibacterial activities. The results of antibacterial agar diffusion tests and near-infrared-mediated tetracycline release tests in vivo confirmed that remote-controlled tetracycline elution using near-infrared laser irradiation was highly effective. Therefore, gold nanorod-sputtered titania nanotubes would be expected to enable the continued use of the photothermal therapy of gold nanorods and extend the limited use of titania showing photocatalytic activity only within the ultraviolet-to-near-infrared region.

16.
J Bone Miner Res ; 33(6): 1126-1140, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29405385

RESUMO

The Sp7/Osterix transcription factor is essential for bone development. Mutations of the Sp7 gene in humans are associated with craniofacial anomalies and osteogenesis imperfecta. However, the role of Sp7 in embryonic tooth development remains unknown. Here we identified the functional requirement of Sp7 for dentin synthesis and tooth development. Sp7-null mice exhibit craniofacial dysmorphogenesis and are completely void of alveolar bone. Surprisingly, initial tooth morphogenesis progressed normally in Sp7-null mice. Thus the formation of alveolar bone is not a prerequisite for tooth morphogenesis. Sp7 is required for mineralization of palatal tissue but is not essential for palatal fusion. The reduced proliferative capacity of Sp7-deficient ectomesenchyme results in small and misshapen teeth with randomly arranged cuboidal preodontoblasts and preameloblasts. Sp7 promotes functional maturation and polarization of odontoblasts. Markers of mature odontoblast (Col1a, Oc, Dspp, Dmp1) and ameloblast (Enam, Amelx, Mmp20, Amtn, Klk4) are barely expressed in incisors and molar tissues of Sp7-null mice. Consequently, dentin and enamel matrix are absent in the Sp7-null littermates. Interestingly, the Sp7 expression is restricted to cells of the dental mesenchyme indicating the effect on oral epithelium-derived ameloblasts is cell-nonautonomous. Abundant expression of Fgf3 and Fgf8 ligand was noted in the developing tooth of wild-type mice. Both ligands were remarkably absent in the Sp7-null incisor and molar, suggesting cross-signaling between mesenchyme and epithelium is disrupted. Finally, promoter-reporter assays revealed that Sp7 directly controls the expression of Fgf-ligands. Together, our data demonstrate that Sp7 is obligatory for the differentiation of both ameloblasts and odontoblasts but not for the initial tooth morphogenesis. © 2018 American Society for Bone and Mineral Research.


Assuntos
Ameloblastos/citologia , Ameloblastos/metabolismo , Diferenciação Celular , Odontoblastos/citologia , Odontoblastos/metabolismo , Fator de Transcrição Sp7/metabolismo , Animais , Animais Recém-Nascidos , Calcificação Fisiológica , Proliferação de Células , Colágeno/metabolismo , Dentina/metabolismo , Desenvolvimento Embrionário , Fatores de Crescimento de Fibroblastos/metabolismo , Regulação da Expressão Gênica , Incisivo/crescimento & desenvolvimento , Incisivo/metabolismo , Incisivo/ultraestrutura , Mesoderma/metabolismo , Camundongos Endogâmicos C57BL , Morfogênese , Palato/metabolismo , Transdução de Sinais , Fator de Transcrição Sp7/deficiência , Fator de Transcrição Sp7/genética , Células-Tronco/metabolismo
17.
J Prosthet Dent ; 118(5): 650-657, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28545871

RESUMO

STATEMENT OF PROBLEM: Studies that evaluated the strength of complete dentures reinforced with glass-fiber mesh or metal mesh on a cast with a simulated oral mucosa are lacking. PURPOSE: The purpose of this in vitro study was to compare the mechanical properties of maxillary complete dentures reinforced with glass-fiber mesh with those of metal mesh in a new test model, using a simulated oral mucosa. MATERIAL AND METHODS: Complete dentures reinforced with 2 types of glass-fiber mesh, SES mesh (SES) and glass cloth (GC) and metal mesh (metal) were fabricated. Complete dentures without any reinforcement were prepared as a control (n=10). The complete dentures were located on a cast with a simulated oral mucosa, and a load was applied on the posterior artificial teeth bilaterally. The fracture load, elastic modulus, and toughness of a complete denture were measured using a universal testing machine at a crosshead speed of 5 mm/min. The fracture load and elastic modulus were analyzed using 1-way analysis of variance, and the toughness was analyzed with the Kruskal-Wallis test (α=.05). The Tukey multiple range test was used as a post hoc test. RESULTS: The fracture load and toughness of the SES group was significantly higher than that of the metal and control groups (P<.05) but not significantly different from that of the GC group. The elastic modulus of the metal group was significantly higher than that of the control group (P<.05), and no significant differences were observed in the SES and GC groups. CONCLUSIONS: Compared with the control group, the fracture load and toughness of the SES and GC groups were higher, while those of the metal group were not significantly different.


Assuntos
Materiais Dentários/uso terapêutico , Prótese Total , Vidro , Mucosa Bucal , Falha de Restauração Dentária , Análise do Estresse Dentário , Humanos , Técnicas In Vitro , Modelos Anatômicos , Suporte de Carga
18.
Dent Mater J ; 36(1): 27-34, 2017 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-27928099

RESUMO

The aims of this study were to evaluate the feasibility of 70% reduced inlay and 4-unit bridge models of International Standard (ISO 12836) assessing the accuracy of laboratory scanners to measure the accuracy of intraoral scanner. Four intraoral scanners (CS3500, Trios, Omnicam, and Bluecam) and one laboratory scanner (Ceramill MAP400) were used in this study. The height, depth, length, and angle of the models were measured from thirty scanned stereolithography (STL) images. There were no statistically significant mean deviations in distance accuracy and precision values of scanned images, except the angulation values of the inlay and 4-unit bridge models. The relative errors of inlay model and 4-unit bridge models quantifying the accuracy and precision of obtained mean deviations were less than 0.023 and 0.021, respectively. Thus, inlay and 4-unit bridge models suggested by this study is expected to be feasible tools for testing intraoral scanners.


Assuntos
Restaurações Intracoronárias , Modelos Dentários , Técnica de Moldagem Odontológica , Imageamento Tridimensional
19.
J Adv Prosthodont ; 8(1): 62-9, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26949489

RESUMO

PURPOSE: The purpose of this study was to evaluate the effects of abutment screw length and cyclic loading on the removal torque (RTV) in external hex (EH) and internal hex (IH) implants. MATERIALS AND METHODS: Forty screw-retained single crowns were connected to external and internal hex implants. The prepared titanium abutment screws were classified into 8 groups based on the number of threads (n = 5 per group): EH 12.5, 6.5, 3.5, 2.5 and IH 6.5, 5, 3.5, 2.5 threads. The abutment screws were tightened with 20 Ncm torque twice with 10-minute intervals. After 5 minutes, the initial RTVs of the abutment screws were measured with a digital torque gauge (MGT12). A customized jig was constructed to apply a load along the implant long axis at the central fossa of the maxillary first molar. The post-loading RTVs were measured after 16,000 cycles of mechanical loading with 50 N at a 1-Hz frequency. Statistical analysis included one-way analysis of variance and paired t-tests. RESULTS: The post-loading RTVs were significantly lower than the initial RTVs in the EH 2.5 thread and IH 2.5 thread groups (P<.05). The initial RTVs exhibited no significant differences among the 8 groups, whereas the post-loading RTVs of the EH 6.5 and EH 3.5 thread groups were higher than those of the IH 3.5 thread group (P<.05). CONCLUSION: Within the limitations of this study, the external hex implants with short screw lengths were more advantageous than internal hex implants with short screw lengths in torque maintenance after cyclic loading.

20.
J Prosthet Dent ; 113(6): 636-44, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25794912

RESUMO

STATEMENT OF PROBLEM: No study has yet evaluated the strength of complete dentures reinforced with glass fiber meshes with different content and structures. PURPOSE: The purpose of this study was to compare the reinforcing effects of glass fiber mesh with different content and structures with that of metal mesh in complete dentures. MATERIAL AND METHODS: Two types of glass fiber mesh were used: SES mesh (SES) and glass cloth (GC2, GC3, and GC4). A metal mesh was used for comparison. The complete dentures were made by placing the reinforcement 1 mm away from the tissue surface. A control group was prepared without any reinforcement (n=10). The compressive properties were measured by a universal testing machine at a crosshead speed of 5 mm/min. The results were analyzed with the Kruskal-Wallis test and the Duncan multiple range test (α=.05). RESULTS: The fracture resistance of the SES group was significantly higher than that of the control, GC4, and metal groups (asymptotic P=.004), but not significantly different from the GC2 and GC3 groups. The toughness of the SES and GC3 groups was significantly higher than that of the others (asymptotic P<.001), but not significantly different from that of the GC4 group. CONCLUSIONS: SES and GC3, which have different structures but similar volume content, were the most effective in reinforcing complete dentures. The content of the glass fiber mesh seemed more important than the structures.


Assuntos
Materiais Dentários/química , Planejamento de Dentadura , Prótese Total , Vidro/química , Força Compressiva , Cobre/química , Ligas Dentárias/química , Falha de Restauração Dentária , Análise do Estresse Dentário/instrumentação , Bases de Dentadura , Prótese Total Superior , Módulo de Elasticidade , Humanos , Teste de Materiais , Estresse Mecânico , Zinco/química
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