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1.
BMC Oral Health ; 21(1): 482, 2021 09 28.
Artigo em Inglês | MEDLINE | ID: mdl-34583658

RESUMO

BACKGROUND: To investigate the efficacy of a nickel-titanium (NiTi) file with an automated computerized numerical control (CNC) system for root canal shaping. METHODS: The movement of the automated device and the insertion angle were investigated. In Experiment 1, simulated resin root canals were randomly divided into four groups (n = 20): manual downward movement using a handpiece (Group 1), vertical downward movement by CNC (Group 2), reciprocating up and down movement by CNC (Group 3), and spiral up and down movement by CNC (Group 4). In Experiment 2, five different insertion angles of the NiTi file were evaluated (n = 20). Four parameters were used to evaluate the shaping ability: change in the working length, central axis offset, curvature variation, and preparation time. Groups were compared using one-way analysis of variance (ANOVA) with significance was set at P < 0.05. RESULTS: The change in central axis position in the curved part of the root canal was found to be smaller in Group 4 than in other groups (P < 0.05). The curvature changes and preparation time of Groups 1 and 4 were significantly reduced compared with Groups 2 and 3 (P < 0.05). The variation in working length and curvature in the 5° insertion angle group was significantly smaller than in the other groups (P < 0.05). CONCLUSIONS: A spiral up and down movement, controlled by the CNC machine, and 5° insertion angle, maintained original root canal shape more precisely than other methods.


Assuntos
Cavidade Pulpar , Níquel , Ligas Dentárias , Desenho de Equipamento , Humanos , Preparo de Canal Radicular , Titânio
2.
Dent Mater J ; 2021 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-34471038

RESUMO

This study aimed to determine functionality and mechanical properties of dental splints. Five splints were tested: a control splint Filtek Z350XT (ZF), two splints with G-Fix (GF) and Light Fix (LF), and two wire-composite splints with ZF (ZW) and Ortho Connect Flow (CW). Periotest values, elastic modulus, flexural, compressive, and diametral tensile strength were measured. ZW and CW showed no significant differences in flexibility in labial or occlusal pressure of upper central incisors. LF, GF, and ZF did not differ in labial or palatal pressure. ZW and CW had higher flexibility than LF, GF, and ZF. LF had the lowest flexural and compressive strength but the highest diametral tensile strength. This study showed that ZW and CW might be options for flexible splints, whereas LF and GF would be options for rigid splints. Additionally, CW and LF/GF might be simpler alternatives to ZW and ZF, respectively.

3.
J Clin Pediatr Dent ; 45(3): 186-192, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34192754

RESUMO

OBJECTIVE: To compare the shear bond strength (SBS) after thermocycling of four universal adhesives applied in self-etch mode on dentin and etch-and-rinse mode on enamel. STUDY DESIGN: Flat 144 buccal or lingual dentin and enamel surfaces from 72 non-carious primary molars were prepared. Samples were segregated into 12 groups (n=12): Adper Single Bond 2 etch-and-rinse (SB_T) and Clearfil SE Bond self-etch (SE_S) applied to enamel and dentin served as controls. Scotch Bond Universal Adhesive (SBU), Clearfil S3 Bond Universal Adhesive (SEU), Tetric N-Bond Universal Adhesive (TEN), and All Bond Universal (BIS) were applied in etch-and-rinse mode to enamel and in self-etch mode to dentin. They were thermocycled for 5000 cycles. SBS testing and the evaluation of fracture mode were performed. RESULTS: SB_T showed statistically higher SBS than other adhesive groups using etch-and-rinse mode on enamel. SE_S and BIS had statistically higher SBS than other adhesive groups using self-etch mode on dentin. Mixed failure was the most common failure mode in each group. CONCLUSION: The universal adhesives did not show higher SBS than SB_T when using etch-and-rinse on enamel. All universal adhesives showed higher SBS than SB_T and had SBS similar to SE_S, except SBU when using self-etch mode on dentin.


Assuntos
Colagem Dentária , Adesivos Dentinários , Esmalte Dentário , Dentina , Humanos , Teste de Materiais , Cimentos de Resina , Resistência ao Cisalhamento , Dente Decíduo
4.
BMC Oral Health ; 21(1): 231, 2021 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-33941165

RESUMO

BACKGROUND: A Case Difficulty Assessment Form was designed for use in endodontic curricula, and to assist practitioners with treatment planning, referral and recording. The aim of this study was to determine how endodontic case difficulty factors influence the operating time of single-visit nonsurgical endodontic treatments under general anesthesia. METHODS: Data on 198 single-visit endodontic treatments (80 anterior teeth, 43 premolars, and 75 molars) performed under general anesthesia by a specialized practitioner were obtained from 119 special needs patients (mean [SD] age = 30.7 [14.7] years). Total duration of operation was analyzed with relation to demographic and dental factors and American Association of Endodontists (AAE) Case Difficulty Assessment factors. Mann-Whitney U test, t-test, and Kruskal-Wallis test were used to assess relationships between operating time and confounding factors (p < 0.05). RESULTS: High difficulty cases required significantly longer time to complete operations than treatments of minimal-to-moderate difficulty regardless of tooth type (p < 0.05). Demographic factors of the patients rarely influenced operating time length. Among variables included in the AAE Case Difficulty Assessment Form, tooth position, crown morphology, root morphology, canal appearance, and periodontal condition were significantly associated with increased operating time (p < 0.05). CONCLUSIONS: A higher level of case difficulty contributed to increased duration of endodontic treatment under general anesthesia indicating that Endodontic Case Difficulty Assessment Form is useful for predicting the duration of nonsurgical endodontic treatment. Among many factors, complicated anatomic features of the treated teeth increased case complexity and extended operating time.


Assuntos
Anestesia Geral , Tratamento do Canal Radicular , Adulto , Assistência Odontológica , Humanos , Dente Molar
5.
Materials (Basel) ; 14(5)2021 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-33800321

RESUMO

The purpose of this study was to observe whether the repetitive firing of dental zirconia caused changes in surface characteristics, S. mutans viability, and optical properties of zirconia. Dental zirconia blocks were sintered and randomly distributed into seven experimental groups: F0-F6. Except for F0, which only went through sintering, the additive firing was performed in order for F1-F6. Surface roughness, contact angle, S. mutans viability by fluorescence, and translucency parameter were measured. They were all highest after sintering (F0) and decreased after additive firings (F1-F6). The additive firing of zirconia after sintering decreased surface roughness, contact angle, S. mutans viability, and translucency. The number of firings after the first firing was not found to be critical in surface characteristics, S. mutans viability, and optical property. Changes in surface characteristics might have led to a decrease in S. mutans viability, while the change of translucency was not clinically significant. This implies that additive firing may prevent secondary caries under zirconia restorations, not compromising esthetic appearance.

6.
Materials (Basel) ; 14(6)2021 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-33803596

RESUMO

With the advent of 3D printing technologies in dentistry, the optimization of printing conditions has been of great interest, so this study analyzed the accuracy of 3D-printed temporary restorations of different sizes produced by digital light processing (DLP) and liquid crystal display (LCD) printers. Temporary restorations of 2-unit, 3-unit, 5-unit, 6-unit, and full-arch cases were designed and printed from a DLP printer using NextDent C&B or an LCD printer using Mazic D Temp (n = 10 each). The restorations were scanned, and each restoration standard tessellation language (STL) file was superimposed on the reference STL file, by the alignment functions, to evaluate the trueness through whole/point deviation. In the whole-deviation analysis, the root-mean-square (RMS) values were significantly higher in the 6-unit and full-arch cases for the DLP printer and in the 5-unit, 6-unit, and full-arch cases for the LCD printer. The significant difference between DLP and LCD printers was found in the 5-unit and full-arch cases, where the DLP printer exhibited lower RMS values. Color mapping demonstrated less shrinkage in the DLP printer. In the point deviation analysis, a significant difference in direction was exhibited in all the restorations from the DLP printer but only in some cases from the LCD printer. Within the limitations of this study, 3D printing was most accurate with less deviation and shrinkage when a DLP printer was used for short-unit restorations.

7.
Dent Mater J ; 40(3): 727-735, 2021 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-33563847

RESUMO

This study aimed to compare the change of surface roughness (Ra) and gloss units (GU) of five dental composites (Filtek Z250, Filtek Z350XT, Metafil CX, Ceram X one, and Venus Diamond) polished with three systems (Sof-Lex XT, Enhance/Pogo, and Sof-Lex Diamond) before/after simulated brushings and to determine the amount of time required to achieve maximum gloss. Ninety rectangular specimens (n=18 per composite) were prepared. Six specimens of each composite were assigned to one of the polishing systems. The Ra and GU of each specimen were measured after each polishing step. Five polished specimens per composite were brushed with a toothbrush machine, and the Ra and GU values were determined. Filtek Z350XT exhibited the most stable and lowest Ra during the brushing cycles regardless of polishing system. When using the Sof-Lex Diamond and Enhance/Pogo systems, the highest gloss and the smoothest surfaces were achieved after polishing and brushing.


Assuntos
Resinas Compostas , Polimento Dentário , Diamante , Teste de Materiais , Propriedades de Superfície , Escovação Dentária
8.
J Appl Biomater Funct Mater ; 18: 2280800020978138, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33371771

RESUMO

The effect of grain size of dental zirconia on the shear bond strength of composite resin cement was newly studied. Disc-shaped dental zirconia with small (sample S) and large (sample L) grains were made by sintering of pre-sintered dental zirconia at 1450°C for 0.5 h and 40 h, respectively. After the sintering, the average grain size of sample S was 1.37 ± 0.15 µm, while that of sample L was 3.74 ± 0.50 µm. The sintered discs were successively polished with different grades of diamond and alumina slurries. The interfacial free energies were 63.5 ± 4.2 dyne/cm for sample S and 52.1 ± 5.5 dyne/cm for sample L. Stainless steel cylinders, previously sandblasted with 50 µm alumina powder, were bonded to the zirconia discs using composite resin cement. Next, samples were kept in an oven for 7 d at 36.5°C. The shear bond strength of sample S was 23.0 ± 4.5 MPa while that of sample L was 17.5 ± 4.6 MPa. After the fracture, the areal % values of composite resin cement remaining on the zirconia surfaces were 89.7 ± 5.9% for sample S and 61.6 ± 5.5% for sample L. The results suggest that grain size reduction has a potential to enhance the degree of bonding between a composite resin cement and a dental zirconia due to the increase of interfacial free energy.

9.
Materials (Basel) ; 13(21)2020 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-33105868

RESUMO

This study compares the color stability of dental reinforced computer-aided design/computer-aided manufacturing (CAD/CAM) hybrid composite blocks to that of regular blocks. One hundred fifty disc-type specimens (n = 15) were prepared from five sets of hybrid composite blocks (Cerasmart-200/Cerasmart-300, KZR-CAD HR/KZR-CAD HR3, Estelite Block/ Estelite-P Block, Avencia Block/Avencia-P Block, Mazic Duro/Duro Ace). The specimen color and translucency parameter (TP) were assessed using a spectrophotometer before and after immersion in staining solutions (water, 10% ethanol, simulated red wine). Changes in color (ΔE) and translucency (ΔTP) of specimens were calculated. The data were analyzed using the analysis of variance (ANOVA) and Tukey's post hoc test (p < 0.05). Microstructural features of the hybrid composite blocks were also examined using FE-SEM. Immersion in deionized water or 10% ethanol made no significant color or translucency changes (except for Avencia-P Block); however, the simulated red wine caused significant changes to the color and translucency of almost all specimens, especially after 4 weeks of immersion. The reinforced hybrid blocks (except for Estelite-P Block and Duro Ace) showed lower color stability than corresponding regular blocks. Avencia-P Block showed significantly reduced color stability compared to Avencia Block. Even in deionized water and 10% ethanol, Avencia-P Block showed perceptible ΔE and decreased translucency. Estelite Block/ Estelite-P Block and Mazic Duro/Duro Ace showed better color stability than the other materials tested.

10.
Materials (Basel) ; 13(18)2020 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-32947875

RESUMO

The purpose of this study is to evaluate the shear bond strength (SBS) of a primer-treated ceramic bracket on dental zirconia and to compare it with conventional ceramic bracket bonding on surface-treated zirconia. Sintered and finished dental zirconia was sandblasted. Samples were divided according to the treated surfaces: no treatment (X), ceramic primer on zirconia (Z), ceramic primer on bracket base (B), and ceramic primer on both zirconia and bracket base (ZB). The ceramic bracket was bonded on zirconia and SBS was measured before (T0) and after 10,000 cycles of thermocycling (Tf). The failed surfaces were examined under field emission scanning electron microscope (FE-SEM), and adhesive remnant index (ARI) was evaluated. SBS was significantly higher in ZB and significantly lower in X in both T0 and Tf. There was no significant difference between Z and B. In X and B, adhesive failure occurred while ZB showed mixed failures. There was no apparent change in the zirconia surface except for the existence of some adhesive and resin remnants. The application of ceramic primer on the bracket base increased the bonding strength to the level of conventional bonding with fewer adhesive remnants. The highest bonding strength was obtained when the primer-treated bracket was bonded on the primer-treated zirconia.

11.
Restor Dent Endod ; 44(4): e39, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31799167

RESUMO

The present report presents a case of dens invaginatus (DI) in a patient with 4 maxillary incisors. A 24-year-old female complained of swelling of the maxillary left anterior region and discoloration of the maxillary left anterior tooth. The maxillary left lateral incisor (tooth #22) showed pulp necrosis and a chronic apical abscess, and a periapical X-ray demonstrated DI on bilateral maxillary central and lateral incisors. All teeth responded to a vitality test, except tooth #22. The anatomic form of tooth #22 was similar to that of tooth #12, and both teeth had lingual pits. In addition, panoramic and periapical X-rays demonstrated root canal calcification, such as pulp stones, in the maxillary canines, first and second premolars, and the mandibular incisors, canines, and first premolars bilaterally. The patient underwent root canal treatment of tooth #22 and non-vital tooth bleaching. After a temporary filling material was removed, the invaginated mass was removed using ultrasonic tips under an operating microscope. The working length was established, and the root canal was enlarged up to #50 apical size and obturated with gutta-percha and AH 26 sealer using the continuous wave of condensation technique. Finally, non-vital bleaching was performed, and the access cavity was filled with composite resin.

12.
J Periodontal Implant Sci ; 49(2): 90-104, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31098330

RESUMO

Purpose: The aim of this study was to evaluate clinical and radiographic changes and the survival rate after periodontal surgery using deproteinized bovine bone mineral (DBBM) with 10% collagen or DBBM with a collagen membrane in endo-periodontal lesions. Methods: A total of 52 cases (41 patients) with at least 5 years of follow-up were included in this study. After scaling and root planing with or without endodontic treatment, periodontal regenerative procedures with DBBM with 10% collagen alone or DBBM with a collagen membrane were performed, yielding the DBBM + 10% collagen and DBBM + collagen membrane groups, respectively. Changes in clinical parameters including the plaque index, bleeding on probing, probing pocket depth, gingival recession, relative clinical attachment level, mobility, and radiographic bone gains were evaluated immediately before periodontal surgical procedures and at a 12-month follow-up. Results: At the 12-month follow-up after regenerative procedures, improvements in clinical parameters and radiographic bone gains were observed in both treatment groups. The DBBM + 10% collagen group showed greater probing pocket depth reduction (4.52±1.06 mm) than the DBBM + collagen membrane group (4.04±0.82 mm). However, there were no significant differences between the groups. Additionally, the radiographic bone gain in the DBBM + 10% collagen group (5.15±1.54 mm) was comparable to that of the DBBM + collagen membrane group (5.35±1.84 mm). The 5-year survival rate of the teeth with endo-periodontal lesions after periodontal regenerative procedures was 92.31%. Conclusions: This study showed that regenerative procedures using DBBM with 10% collagen alone improved the clinical attachment level and radiographic bone level in endo-periodontal lesions. Successful maintenance of the results after regenerative procedures in endo-periodontal lesions can be obtained by repeated oral hygiene education within strict supportive periodontal treatment.

13.
Materials (Basel) ; 12(10)2019 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-31137486

RESUMO

The aim of this study was to evaluate the long term stability of shear bond strength (SBS) when 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) containing universal adhesive was used in the ceramic bracket bonding on dental zirconia. Twenty human maxillary incisors were collected. The ceramic bracket was bonded on the buccal enamel surface after the acid-etching and orthodontic primer application (Group CON). Sixty zirconia specimens were sintered, sandblasted and divided into three experimental groups; group CP-ceramic primer followed by an orthodontic primer; group U-universal adhesive; group CU-ceramic primer followed by a universal adhesive. For each specimen, the bracket was bonded onto the treated surface with composite resin (Transbond XT, 3M ESPE). The SBS tested before (CON0, CP0, U0, CU0) and after the artificial aging (CON1, CP1, U1, CU1). The data were statistically analyzed with the Kruskal-Wallis test at a significance level of 0.05. The mean SBS of CON0, CP0, U0 and CU0 were within the clinically acceptable range without significant differences. After the aging process, SBS decreased in all groups. Among the aged groups, CP1 showed the highest SBS. Based on the results, when bonding ceramic brackets to a dental zirconia surface, we can conclude that ceramic primer used with an orthodontic primer, rather than using a universal adhesive, is recommended.

14.
J Clin Biochem Nutr ; 64(2): 97-105, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30936621

RESUMO

Fisetin was reported to have an anti-proliferative and apoptotic activity as a novel anti-cancer agent in various cancer cell lines. However, the possible molecular targets for the anti-cancer effect of fisetin in human head and neck cancer (HNCC) have not yet been clarified. In this study, the influence of fisetin on the growth and apoptosis of HNCCs were examined. In HSC3 cells, fisetin treatment reduced the viability and induced apoptosis. Through the results from the screening of the expression profile of apoptosis-related genes, sestrin 2 (SESN2) was functionally involved in fisetin-mediated apoptosis showing the knockdown of SESN2 by siRNA clearly restored fisetin-induced apoptosis. In addition, fisetin reduced the protein expression levels of phospho-mTOR (p-mTOR) and Mcl-1, which are the downstream molecules of SESN2. It also induced PARP cleavage by inducing an increase in the expression levels of SESN2 together with reducing mTOR and Mcl-1 proteins in other three HNCCs (MC3, Ca9.22, and HN22). Taken together, our findings suggest that the anti-cancer effect of fisetin on HNCCs is associated with SESN2/mTOR/Mcl-1 signaling axis.

15.
J Endod ; 45(2): 116-122, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30711166

RESUMO

INTRODUCTION: The aim of this study was to determine the prognostic factors of periapical healing of teeth after single-visit nonsurgical endodontic treatment under general anesthesia in special needs patients. METHODS: This retrospective study collected 448 teeth from 241 patients (mean age = 27.4 years, standard deviation = 13.9 years). A total of 271 teeth (60.5%) with clinical and radiographic follow-up records longer than 12 months (mean [standard deviation] = 56.1 [27.9]) were included in the outcome analysis. Demographic, systemic, and dental information about the cases were compared between the healed and nonhealed groups using the Pearson chi-square test. Factors contributing to periapical healing were determined with multivariate logistic regression analysis. RESULTS: Complete periapical healing without clinical signs was observed in 221 teeth (81.5%), uncertain healing with decreased size of the periapical lesion was shown in 43 teeth (15.9%), and no reduction in lesion size was observed in 7 cases (2.6%). In the multivariate analysis, diet type, oral hygiene maintenance, pulp vitality, and root filling length were detected as contributing factors for complete resolution of periapical lesions (P < .05). CONCLUSIONS: Successful outcomes of single-visit endodontic treatment under general anesthesia were shown in special needs patients. The prognoses were influenced by the clinical circumstances of the patients and the preoperative conditions of their teeth.


Assuntos
Anestesia Geral , Transtornos da Comunicação , Deficiência Intelectual , Doenças Periapicais/fisiopatologia , Doenças Periapicais/cirurgia , Tratamento do Canal Radicular , Ápice Dentário/fisiopatologia , Cicatrização , Adolescente , Adulto , Dieta , Feminino , Seguimentos , Humanos , Masculino , Higiene Bucal , Prognóstico , Estudos Retrospectivos , Inquéritos e Questionários , Fatores de Tempo , Adulto Jovem
16.
Materials (Basel) ; 11(7)2018 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-30021991

RESUMO

This study investigated the influences of acidity, ethanol, and pigment on the optical properties, microhardness, and surface roughness (Ra) of a nanohybrid dental composite resin. A total of 108 disc-shaped specimens were fabricated using a nanohybrid dental composite and allocated into 36 different storage solutions according to the levels of pH (2.0, 3.0, 4.0, and 5.5), ethanol (0%, 20%, and 40%), and anthocyanin pigment (0%, 2.5%, and 12.5%). Measurements of the colorimetric parameter and the amount of color change (ΔE), translucency parameter (TP), microhardness, and surface roughness (Ra) were performed at 24 h (baseline), 1-, 2-, 3-, and 4-weeks. Repeated measures of analysis of variance (ANOVA) with a Tukey honestly significant difference test and Pearson correlation analysis were carried out (α = 0.05). Pigment of 12.5% or 40% ethanol significantly increased the ΔE (P < 0.001, P = 0.048, respectively). Pigment of 2.5% or 12.5% significantly decreased the TP (P = 0.001, P < 0.001, respectively). Microhardness of composite resin stored in pH 2.0, 3.0, 4.0 solution was lower than that for pH 5.5 (P < 0.001). Pigment, ethanol, and pH did not influence the Ra. TP change and ΔE, and Ra and ΔE had a significant positive correlation (P < 0.05). In conclusion, pigment and ethanol levels influenced the optical properties and acidity affected the microhardness of composite resin.

17.
ACS Appl Mater Interfaces ; 10(21): 17526-17541, 2018 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-29741358

RESUMO

Nanofibrous engineered matrices have significant potential in cellular differentiation and tissue regeneration. Stem cells require specific extracellular signals that lead to the induction of different lineages. However, the mechanisms by which the nanofibrous matrix promotes mesenchymal stem cell (MSC) differentiation are largely unknown. Here, we investigated the mechanisms that underlie nanofibrous matrix-induced odontoblastic differentiation of human dental pulp MSCs (DP-MSCs). An electrospun polystyrene nanofibrous (PSF) matrix was prepared, and the cell responses to the PSF matrix were assessed in comparison with those on conventional tissue culture dishes. The PSF matrix promoted the expression of Wnt3a, Wnt5a, Wnt10a, BMP2, BMP4, and BMP7 in the DP-MSCs, concomitant with the induction of odontoblast/osteoblast differentiation markers, dentin sialophosphoprotein (DSPP), osteocalcin, and bone sialoprotein, whose levels were further enhanced by treatment with recombinant Wnt3a. The DP-MSCs cultured on the PSF matrix also exhibited a high alkaline phosphatase activity and intense Alizarin Red staining, indicating that the PSF matrix promotes odontoblast differentiation. Besides inducing the expression of Wnt3a, the PSF matrix maintained high levels of ß-catenin protein and enhanced its translocation to the nucleus, leading to its transcriptional activity. Forced expression of LEF1 or treatments with LiCl further enhanced the DSPP expression. Blocking the Wnt3a-initiated signaling abrogated the PSF-induced DSPP expression. Furthermore, the cells on the PSF matrix increased the DSPP promoter activity. The ß-catenin complex was bound to the conserved motifs on the DSPP promoter dictating its transcription. Transplantations of the preodontoblast-seeded PSF matrix to the subcutaneous tissues of nude mice confirmed the association of the PSF matrix with the Wnt3a and DSPP expressions in vivo. Taken together, these results demonstrate the nanofibrous engineered matrix strongly supports odontoblastic differentiation of DP-MSCs by enhancing Wnt/ß-catenin signaling.


Assuntos
Células-Tronco , Animais , Diferenciação Celular , Polpa Dentária , Proteínas da Matriz Extracelular , Humanos , Camundongos , Camundongos Nus , Via de Sinalização Wnt
18.
Biomaterials ; 149: 77-87, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29017079

RESUMO

Host responses to a biomaterial critically influence its in vivo performance. Biomaterial architectures that can recruit endogenous host stem cells could be beneficial in tissue regeneration or integration. Here, we report that the fibrous topography of biomaterials promotes the recruitment of host mesenchymal stem cells (MSCs) by facilitating the macrophage phenotype transition from M1-to-M2. Electrospun poly (ε-caprolactone) fiber (PCL-fiber) films were implanted into the subcutaneous tissues of rats, and the response of host cells to the PCL-fiber was evaluated and compared with those of solid ones (PCL-solid). During the initial post-implantation period, greater numbers of cells were recruited and adhered to the PCL-fiber compared to the PCL-solid, and the cells exhibited the M1 phenotype, which was supported by the enhanced adsorption of complement C3a to the implanted PCL-fiber. Subsequently, the PCL-fiber supported the macrophage phenotype transition from M1-to-M2, which was confirmed by the ratio of M2/M1 marker (CD163/CCR7)-positive cells and by the expression of M2/M1 markers (arginase-1/iNOS). The PCL-fiber also reduced the formation of foreign body giant cells. MSC marker (CD29, CD44, and CD90)-positive cells began to appear as early as day 4 on the PCL-fiber, while few MSCs were observed on the PCL-solid. The MSCs migration ex vivo assay showed that MSCs substantially migrated across the trans-wells toward the implanted PCL-fiber. The cells on the implanted PCL-fiber expressed and secreted substantial levels of SDF-1 (CXCL-12), while anti-SDF-1 neutralizing antibody abrogated the MSCs migration. Taken together, these results provide evidence that the fibrous topography of biomaterials enhances the recruitment of MSCs by promoting macrophage recruitment, facilitating M1-to-M2 transition, and enhancing SDF-1 secretion.


Assuntos
Macrófagos/citologia , Células-Tronco Mesenquimais/fisiologia , Poliésteres/química , Animais , Biomarcadores/metabolismo , Adesão Celular , Movimento Celular , Quimiocina CXCL12/metabolismo , Humanos , Macrófagos/fisiologia , Masculino , Células-Tronco Mesenquimais/citologia , Fenótipo , Ratos Sprague-Dawley , Tecidos Suporte
19.
Korean J Orthod ; 47(4): 229-237, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28670564

RESUMO

OBJECTIVE: The aim of this study was to compare the initial stability as insertion and removal torque and the clinical applicability of novel orthodontic zirconia micro-implants made using a powder injection molding (PIM) technique with those parameters in conventional titanium micro-implants. METHODS: Sixty zirconia and 60 titanium micro-implants of similar design (diameter, 1.6 mm; length, 8.0 mm) were inserted perpendicularly in solid polyurethane foam with varying densities of 20 pounds per cubic foot (pcf), 30 pcf, and 40 pcf. Primary stability was measured as maximum insertion torque (MIT) and maximum removal torque (MRT). To investigate clinical applicability, compressive and tensile forces were recorded at 0.01, 0.02, and 0.03 mm displacement of the implants at angles of 0°, 10°, 20°, 30°, and 40°. The biocompatibility of zirconia micro-implants was assessed via an experimental animal study. RESULTS: There were no statistically significant differences between zirconia micro-implants and titanium alloy implants with regard to MIT, MRT, or the amount of movement in the angulated lateral displacement test. As angulation increased, the mean compressive and tensile forces required to displace both types of micro-implants increased substantially at all distances. The average bone-to-implant contact ratio of prototype zirconia micro-implants was 56.88 ± 6.72%. CONCLUSIONS: Zirconia micro-implants showed initial stability and clinical applicability for diverse orthodontic treatments comparable to that of titanium micro-implants under compressive and tensile forces.

20.
Angle Orthod ; 87(2): 307-312, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27598781

RESUMO

OBJECTIVE: To compare the antimicrobial and physical properties of experimental primers containing chlorhexidine (CHX) or ursolic acid (UA) with a commercial primer. MATERIALS AND METHODS: Two antibacterial agents, 3 mg each of CHX and UA were incorporated respectively into 1 ml of Transbond XT primer (TX) to form antibacterial primers, TX-CHX and TX-UA. The antimicrobial activity of the three primers (TX, TX-CHX, and TX-UA) against Streptococcus mutans in both planktonic and biofilm phases was analyzed by determining minimum inhibitory and bactericidal concentrations and by performing growth and biofilm assays. Growth and biofilm assays were performed in both the absence and presence of thermocycling in a water tank to analyze the effects of water aging on the antimicrobial activities of primers. After bonding brackets onto bovine incisors using the primers, shear bond strength and mode of fracture were analyzed to compare physical properties. RESULTS: TX-CHX had stronger antimicrobial activity against S. mutans in the planktonic and biofilm phases than did TX or TX-UA. When applied, TX-CHX completely inhibited the growth and biofilm formation of S. mutans . In addition, the antimicrobial activity of TX-CHX was maintained after thermocycling. However, TX-UA did not show significant antimicrobial activity compared with TX. There was no significant difference in either shear bond strength or bond failure interface among the primers. CONCLUSION: Incorporation of CHX into an orthodontic primer may help prevent enamel demineralization around surfaces without compromising its physical properties.


Assuntos
Anti-Infecciosos/farmacologia , Biofilmes/crescimento & desenvolvimento , Clorexidina/farmacologia , Braquetes Ortodônticos , Cimentos de Resina/farmacologia , Streptococcus mutans/efeitos dos fármacos , Desmineralização do Dente/prevenção & controle , Triterpenos/farmacologia , Animais , Bovinos , Colagem Dentária , Técnicas In Vitro , Testes de Sensibilidade Microbiana , Propriedades de Superfície
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