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1.
J Contemp Dent Pract ; 21(6): 615-620, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33025928

RESUMO

AIM: The aim of this study is to compare the effect of the use of second-generation and third-generation LED light-curing units (LCUs) on the degree of conversion (DC) and microhardness (VHN) of bulk-fill resin composites. MATERIALS AND METHODS: Thirty cylindrical specimens (each n = 5) of Tetric N-Ceram Bulk-Fill, Filtek™ Bulk-Fill Posterior Restorative, and SDR flow were prepared in metal molds (5 mm in diameter and 4 mm in thickness) and cured with second-generation LED (SmartLite® Focus®, Dentsply Sirona) and third-generation LED (Bluephase® style, Ivoclar Vivadent) resulting in six groups. Degree of conversion was determined using Fourier transform infrared spectroscopy (FTIR), and microhardness with Vickers microhardness tester. Data were statistically analyzed using one-way ANOVA and least significance difference (LSD) test, and DC and microhardness were correlated using Pearson's correlation (α = 0.05). RESULTS: There was a significant difference between DC and VHN between all groups of bulk-fill which were cured by second-generation LED curing light and third-generation LED curing light. Then there is no significant difference between DC of the three composite bulk-fill resins by (second-generation LED vs third-generation LED curing light). CONCLUSION: The second-generation LED curing light can still be used to cure bulk-fill resin composites by increasing the duration of irradiation. CLINICAL SIGNIFICANCE: In the microhardness test, there was a significant difference in the Filtek™ Bulk-Fill Posterior Restorative resin composites.


Assuntos
Resinas Compostas , Luzes de Cura Dentária , Teste de Materiais , Polimerização , Espectroscopia de Infravermelho com Transformada de Fourier
2.
J Contemp Dent Pract ; 21(6): 691-695, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33025941

RESUMO

AIM: The longevity of restorative materials depends on the resistance to masticatory forces. The present study was undertaken to evaluate the mechanical and microleakage properties of Cention-N with glass ionomer cement (GIC) and composite restorative materials. MATERIALS AND METHODS: A total of 45 specimen blocks were prepared with 15 samples of each type of restorative material, namely Cention-N, GIC, and hybrid composite. Samples were subjected to load at crosshead speed of 0.75 ± 0.25 mm/min till the fracture of sample. Class V cavities were prepared on the buccal surface of orthodontically extracted premolars followed by restoration of each test material. All the surfaces of the tooth were coated with clear nail varnish except 1 mm around the margins of the restorations. These samples were immersed in 0.5% basic fuchsine dye and longitudinally sectioned and observed under stereomicroscope to check microleakage. The obtained data were statistically evaluated. RESULTS: We found the highest mean compressive and flexural strength for hybrid composite followed by Cention-N and least for GIC which is statistically significant (p < 0.001). CONCLUSION: Mean microleakage was least for Cention-N. Cention-N is a newer restorative material having higher mechanical properties with lesser microleakage. CLINICAL SIGNIFICANCE: Cention-N is a newer restorative material having promising properties. This material can be used as an alternative restorative material.


Assuntos
Infiltração Dentária , Resinas Compostas , Materiais Dentários , Restauração Dentária Permanente , Cimentos de Ionômeros de Vidro , Humanos
3.
Am J Dent ; 33(5): 227-234, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33017523

RESUMO

PURPOSE: To evaluate the influence of different post-endodontic techniques on the fatigue survival and biomechanical behavior of crowned restored central incisors. METHODS: The crowns of 69 bovine incisors were cut, and the roots were treated endodontically and assigned randomly into three groups (n=23): resin composite buildup (BUP), glass fiber post-retained resin composite buildup (GFP), and cast post-and-core (CPC). They received full crown preparation with 2 mm ferrule, and a leucite-reinforced ceramic crown was cemented adhesively. Three specimens from each group were tested monotonically. The remaining specimens were subjected to the stepwise stress fatigue test until fracture or suspension after 1.5 x 106 cycles in a chewing simulator. The load and step at which each specimen failed were analyzed by Kaplan-Meier and Mantel-Cox (log-rank test) statistics, followed by multiple pairwise comparisons, at 5% significance level. The three groups tested (BUP, GFP, and CPC) were 3D modeled (Rhinoceros 4.0) and the maximum principal stress (MPa) criteria were used to calculate the results using FEA. RESULTS: There was no statistical difference between the treatments regarding the load or the number of cycles (Mantel-Cox log-rank test for trend, X²= 0.015, df=1, P= 0.901, X²=3.171, df=1, P= 0.995). Crown cracks were the predominant failure mode, and oblique root fractures were only observed in groups GFP and CPC. In endodontically treated incisors with a 2-mm ferrule, the post-endodontic treatment had no significant effect on fatigue survival. Non-restorable fractures only occurred in teeth restored with posts. CLINICAL SIGNIFICANCE: Although the clinical significance of laboratory studies has some limitations, this study suggests that composite buildups without posts may be an option for restoring endodontically treated incisors with 2 mm ferrule height.


Assuntos
Incisivo , Técnica para Retentor Intrarradicular , Animais , Bovinos , Resinas Compostas , Coroas , Análise do Estresse Dentário
4.
J Contemp Dent Pract ; 21(7): 741-747, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33020356

RESUMO

AIM: This study was aimed to compare the microleakage of amalgam restorations repaired with bonded amalgam, composite resin, ormocer, and glass ionomer restorative material. MATERIALS AND METHODS: Sixty extracted maxillary human premolars were prepared and restored with class I amalgam. A simulated defect was prepared that included the cavosurface margin on restorations, and the premolars were assigned to four treatment groups (n = 15): In group I, premolars were treated by bonded amalgam; in group II, premolars were repaired with composite resin; in group III, premolars were repaired by ormocer; and in group IV, premolars were repaired with glass ionomer restorative material. The teeth were immersed in 50% silver nitrate solution, thermocycled, sectioned longitudinally, and then blindly observed under a stereomicroscope by three trained examiners. Microleakage was evaluated using a 0-4 scale for dye penetration, and data were analyzed by Kruskal-Wallis test and Mann-Whitney U-test. RESULTS: The microleakage values were more in the group repaired with glass ionomer restorative material and the Chi-squared test showed no significant difference in between the groups repaired with bonded amalgam, composite resin, and ormocer, but showed significant difference between the groups repaired with ormocer and glass ionomer restorative materials and between composite resin and glass ionomer restorative materials. CONCLUSION: None of the restorative techniques evaluated were able to completely eliminate marginal microleakage. CLINICAL SIGNIFICANCE: The results seem to be favorable within the limits of the in vitro conditions of the present study; however, the in vivo conditions are the best for clinically relevant findings.


Assuntos
Infiltração Dentária , Restauração Dentária Permanente , Resinas Compostas , Cimentos de Ionômeros de Vidro , Humanos , Cerâmicas Modificadas Organicamente
5.
J Contemp Dent Pract ; 21(7): 781-786, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33020363

RESUMO

AIM: This study aimed to assess the microleakage of a self-adhesive composite compared to conventional composites in class V cavities. MATERIALS AND METHODS: In this in vitro experimental study, standard class V cavities were prepared in the buccal surface of 204 extracted teeth and randomly divided into six groups for restoration with (A) Vertiseflow (Kerr) self-adhesive composite, (B) acid etching (Kerr) + Vertiseflow, (C) acid etching + Optibond FL (Kerr) + Vertiseflow, (D) Er,Cr:YSGG laser + Vertiseflow, (E) acid etching + Optibond FL + Premise Flowable (Kerr), and (F) acid etching + Optibond FL + Z250 (3M). The teeth in each group were then randomly divided into two subgroups of with and without thermocycling (10,000 cycles between 5°C and 55°C). The microleakage was then determined at the enamel and dentin margins under a stereomicroscope using the dye penetration method. Data were analyzed using the Kruskal-Wallis test (α = 0.05). RESULTS: No significant difference was noted in occlusal margin microleakage of no thermocycling groups, but acid etching + Vertiseflow showed the highest microleakage. At the gingival margin, the difference between acid etching + bonding agent + Z250 and laser + Vertiseflow was significant (p = 0.004). In thermocycling groups, the difference in the microleakage at the occlusal margin of Vertiseflow with that of acid etching + bonding agent + Premise (p = 0.002), acid etching + bonding agent + Vertiseflow (p = 0.009), and acid etching + bonding agent + Z250 (p = 0.037) groups was significant. The difference in the microleakage at the dentin margin was also significant among the groups (p < 0.05). The highest and the lowest microleakages were noted in laser + Vertiseflow and acid etching + bonding agent + Vertiseflow groups, respectively. CONCLUSION: Surface preparation with etching and adhesive application results in lower microleakage in class V cavities. But laser irradiation and the use of self-adhesive composite increase the microleakage. CLINICAL SIGNIFICANCE: It seems that self-adhesive composites cannot provide acceptable marginal integrity without any surface treatment.


Assuntos
Infiltração Dentária , Cimentos de Resina , Resinas Compostas , Cimentos Dentários , Restauração Dentária Permanente , Humanos
7.
Beijing Da Xue Xue Bao Yi Xue Ban ; 52(5): 907-912, 2020 Oct 18.
Artigo em Chinês | MEDLINE | ID: mdl-33047728

RESUMO

OBJECTIVE: To evaluate the clinical success of the treatment of maxillary anterior primary incisors caries with composite resin strip crowns. METHODS: Children who presented with severe early childhood caries and were treated comprehensive caries under general anesthesia from January to December 2016 were enrolled in this study. Composite crowns using preformed celluloid crown (3M ESPE, USA) called as "strip crown technique" were applied to treat vital primary incisors with two or multiple surface cavities. Selective etchings of enamel, Universal Bond adhesive and 3M Z350 resin were used to make strip crowns. The patients returned at the end of 6, 12 and 18 months and received clinical and radiologic examinations. Dentists who did not attend the treatment evaluated the strip crowns clinically by modified United States Public Health Service (USPHS) criteria. RESULTS: Four hundred eighteen restorations, placed in 127 children aged 1.17-5.75 years (average of 3.22), were evaluated. The overall retention rate was 97.8% at the end of 6 months, 93.6% at 12 months and 89.2% at 18 months. After 18 months, 28 restorations (6.7%) were totally lost and 4.1% were rated as having lost some resin material. Only four teeth (1.0%) had secondary caries at the end of 18 months and 1.4% teeth had pulpal pathology requiring root canal treatment. Composite crowns had good performance in contour and adjacent contact and improved aesthetics significantly. Twenty-nine teeth (6.9%) showed mild gingivitis and 93.1% showed healthy gingival. 11.2% of the teeth demonstrated color change because plaque accumulation and the polish could remove the stains. The complete loss of strip crowns was mainly related to eating bites. CONCLUSION: Strip crowns performed well for restoring primary incisors with large or multisurface caries for periods of over 18 months. The strip crowns can be a durable and aesthetic restoration for vital carious primary incisors with adequate tooth structure after caries removal. Functional movement is an important cause of complete loss. Because of the high technical sensitivity and its requirement of the cooperation of children, strip crowns are more suitable for older and cooperative children as well as children receiving dental treatment under sedation or general anesthesia.


Assuntos
Incisivo , Dente Decíduo , Criança , Pré-Escolar , Resinas Compostas , Coroas , Humanos , Lactente , Maxila , Estados Unidos
8.
Wiad Lek ; 73(8): 1677-1680, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33055333

RESUMO

OBJECTIVE: The aim of this study was to compare the wear resistance of such restorative materials as composite resin, feldspathic ceramic, leucite glass ceramic with intact enamel and to draw an analogy with some similar researches. PATIENTS AND METHODS: Materials and methods: In this research 20 extracted human teeth (maxillary incisors) without fillings and carious cavities were used as samples. All samples were disinfected and stored in saline in order to prevent dehydration. Teeth roots were cut off for the measure of fixation on an organic glass plate using chemically polymerizable resin. If necessary, the teeth were also cut on their lateral sides in order to give them equal size. The samples were placed in a frame-holder, located on the lever of the machine MI-2, which determines abrasion resistance under slipping. RESULTS: Results: The research has revealed that the average wear resistance of natural teeth was 122,67±4.9 J/mm3 (Tab 1). The archived result overcomes dental composite resin twice more (62.8±1.21 J/mm3), feldspathic ceramic 6.5 times more (16.32±1.2 J/mm3) and leucite ceramic over the half (73.79±3.12 J/mm3). CONCLUSION: Conclusion: Thus, according to this performed research and the analysis of the relative literature sources it can be stated that dental composite resin and leucite ceramics may be proposed as the materials of choice for anterior restoration of teeth. They have shown the good wear resistance and tolerance to antagonizing natural teeth.


Assuntos
Resinas Compostas , Humanos
9.
Chin J Dent Res ; 23(3): 215-220, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32974622

RESUMO

The main goal of this report was to solve a clinical case of a 73-year-old man with diabetes, partial edentulism and a pathological occlusion with biocorrosion using conservative and adhesive techniques. A complete rehabilitative treatment was performed, increasing the vertical dimension of occlusion using indirect restorations with composite resins on teeth and resin crowns on implants and returning function using mutually protected occlusion. A 6-month posttreatment clinical and radiographic follow-up was performed.


Assuntos
Falha de Restauração Dentária , Estética Dentária , Idoso , Resinas Compostas , Coroas , Planejamento de Prótese Dentária , Humanos , Masculino , Dimensão Vertical
10.
Braz Dent J ; 31(4): 440-444, 2020 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-32901722

RESUMO

Posterior build-ups are auxiliary devices to orthodontic treatment which are made with resin-based or glass ionomer composites. Their removal requires care to protect the tooth surface, therefore, pigmented materials are preferred for a better visualization. This study proposed a pigmentation experimental technique of a regular composite resin, evaluating the microshear bond strength test (µ-SBT) of this experimental pigmented resin and comparing with a blue-colored polyacid-modified composite resin, used for posterior buildups. Forty-eight buccal and lingual surfaces of human teeth were used and randomly divided into 4 groups (n=12). The groups were divided into: C (control), regular composite resin; P, regular composite resin pigmented; UBL, Ultra Band Lok™; OB, Ortho Bite™. The composites were bonded using a matrix to obtain microcylinders and prepared for each experimental groups. The samples were then stored in distilled water for 24h at 37°C followed by a µ-SBT. The types of bond failures were evaluated using a stereoscopic magnifying glass (10×). The data were analyzed by ANOVA with Fisher post hoc and Dunnett´s test. Means of µ-SBT± standard deviation (MPa) were: C (39.98a±13.0), P (40.09a± 14.3); UBL (33.26ab±8.6); OB (28.70b±5.5). The most prevalent type of failure was adhesive (80.4%). Further, was not observed a statistically significant correlation between the bond strength values and failure patterns. The pigmentation of a commercially available resin did not alter the µ-SBT and exhibited similar adhesiveness as a polyacid-modified composite resin.


Assuntos
Resinas Compostas , Colagem Dentária , Cimentos de Ionômeros de Vidro , Humanos , Teste de Materiais , Pigmentação , Cimentos de Resina
11.
Hua Xi Kou Qiang Yi Xue Za Zhi ; 38(4): 438-442, 2020 Aug 01.
Artigo em Chinês | MEDLINE | ID: mdl-32865365

RESUMO

Noncarious cervical sclerotic lesions (NCSL) are dental cervical lesions with noncarious sclerotic dentine (NCSD), which appears smooth, hard, and either light yellow or dark brown. Most NCSLs are wedge or dish shaped and commonly occur in canines and premolars, leading to dental hypersensitivity and aesthetic defect. The principal treatment is composite resin restoration; however, many clinical problems, such as retention loss, should not be ignored. NCSL's bonding interface includes NCSD and enamel, and interface pre-treatment can promote the bonding effect. This review summarizes current surface treatment methods and their influence on the bonding effectiveness of NCSL to provide guidance for clinical practice.


Assuntos
Colagem Dentária , Adesivos Dentinários , Condicionamento Ácido do Dente , Resinas Compostas , Restauração Dentária Permanente , Colo do Dente
12.
Int J Prosthodont ; 33(5): 523-526, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32956433

RESUMO

PURPOSE: To investigate the three-point flexural strength of a novel CAD/CAM fiber-reinforced composite (FRC) material following different aging conditions. MATERIALS AND METHODS: The specimens were randomly assigned to one of five groups based on aging condition: (1) control (no treatment); (2) short-term water storage; (3) thermal degradation with autoclaving; (4) chemical degradation with hydrochloric acid; and (5) chemical degradation with citric acid (n = 10 per group). The specimens in the control group received no treatment. Following each treatment protocol, the three-point bending test was used to calculate the flexural strength. Data were statistically analyzed (α = .05), and scanning electron microscopy (SEM) analysis of the specimens was conducted. RESULTS: No significant differences in flexural strength were observed among the groups (P = .199). In addition, no distinct morphologic differences were detected in the SEM images of the specimens. CONCLUSION: The flexural strength of this novel CAD/CAM FRC material was unaffected by different aging methods.


Assuntos
Resinas Compostas , Resistência à Flexão , Desenho Assistido por Computador , Teste de Materiais , Microscopia Eletrônica de Varredura , Projetos Piloto , Maleabilidade , Estresse Mecânico , Propriedades de Superfície
13.
Int J Prosthodont ; 33(5): 536-545, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32956435

RESUMO

PURPOSE: To evaluate the shear bond strength (SBS) and color stability (ΔE) of four ceramic veneers (VITA VM 9; VITA VM 13; VITA VMK 95; and IPS e.max Ceram) following repair with three different self-adhesive composite resins (Fusio Liquid Dentin; Constic; and Vertise Flow) and BISCO Intraoral Repair Kit + Filtek Supreme (BC + FS). MATERIALS AND METHODS: A total of 96 specimens were prepared per ceramic material, and each ceramic group was divided into subgroups according to testing method (32 specimens for color stability analysis and 64 specimens for SBS testing). ΔE and SBS (SBS1 = non-aged, SBS2 = thermally aged) values of the repaired specimens were calculated. One specimen from each of the thermally aged groups was investigated under scanning electron microscopy (SEM). Two-way ANOVA was used to analyze the mean ΔE, SBS1, and SBS2 values. The differences between SBS1 and SBS2 values were analyzed using independent-samples t test. RESULTS: The lowest ΔE values were calculated for Constic (P ≤ .05). The SBS2 values among all groups were lower than the SBS1 values (P ≤ .05). The lowest SBS2 values were observed for Vertise Flow (2.3 ± 1.47 MPa) (P ≤ .05) and were below the acceptable limit of 5 MPa. CONCLUSION: All of the investigated repair materials in combination with the ceramic veneers exhibited ΔE values that were higher than the clinically acceptable limits. Thermal aging negatively affected the SBS values in all groups (P ≤ .05). All tested self-adhesive composite resins, with the exception of Vertise Flow, could be used instead of a repair kit with flowable composite resin, especially in noncooperative patients, for the purpose of repairing chipping fractures for VITA VM 9, VITA VM 13, and VITA VMK 95 (P > .05).


Assuntos
Colagem Dentária , Cimentos Dentários , Resinas Acrílicas , Cerâmica , Cor , Resinas Compostas , Porcelana Dentária , Humanos , Teste de Materiais , Cimentos de Resina , Resistência ao Cisalhamento , Propriedades de Superfície
14.
Acta Odontol Latinoam ; 33(2): 59-68, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32920607

RESUMO

The aim of this in vitro study was to evaluate the effect of bleaching protocols on the surface roughness (Ra), color change and surface micromorphology of a low-viscosity bulk-fill composite (Filtek Bulk Fill Flow, 3M ESPE), a highviscosity bulk-fill composite (Filtek Bulk Fill, 3M ESPE) and a conventional nanoparticulate composite resin (control) (Filtek Z350 XT, 3M ESPE). Forty samples of each composite (disks 5 mm in diameter and 2 mm thick) were randomly divided into four groups (n=10), according to bleaching protocol: a) 10% carbamide peroxide gel (Opalescence, Ultradent Products) (2 h/ day, for 14 days); b) 40% hydrogen peroxide gel (Opalescence Boost, Ultradent Products) (three bleaching sessions, once a week, 45 min/session); c) whitening rinse (Listerine Whitening Extreme, Johnson & Johnson) (2 min/day, for 14 days); and d) distilled water (control). The samples were submitted to triplicate readings (Ra and color [CIELAB parameters]) before and after contact with bleaching protocols. Micromorphology was analyzed in a scanning electron microscope (SEM). Ra and color parameters (ΔL, Δa, Δb and ΔE) were analyzed by generalized linear models (α=0.05). The Ra of the high-viscosity bulk-fill was significantly higher than that of the other composites (p<0.05). Ra increased significantly (p<0.05) and surface became more irregular (SEM analysis) in all the composite resins, regardless of the bleaching protocol (p<0.05). The high-viscosity bulk-fill composite resin group had significantly lower ΔE (p<0.05) than the nanoparticulate composite resin group immersed in distilled water. It was concluded that the characteristics of each resin significantly influenced the Ra more than the bleaching protocol. The high-viscosity bulk-fill resin presented minor color change.


Assuntos
Resinas Compostas/química , Peróxido de Hidrogênio/química , Clareadores Dentários/química , Clareamento Dental/métodos , Descoloração de Dente/tratamento farmacológico , Viscosidade/efeitos dos fármacos , Cor , Humanos , Teste de Materiais
15.
Braz Oral Res ; 34: e095, 2020 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-32901725

RESUMO

The purpose of this study was to synthesize dicalcium phosphate dihydrate (DCPD) particles functionalized with triethylene glycol dimethacrylate (TEGDMA) through different routes by varying the receptor solution: ammonium phosphate (AP groups) or calcium nitrate (CN groups) and the moment in which TEGDMA was incorporated: ab initio (ab) or at the end of dripping the solution (ap). Two syntheses were performed without adding TEGDMA (nf). The particles were characterized by X-ray diffractometry, true density (using a helium pycnometer), surface area, and scanning electron microscopy. A 20 vol% of DCPD particles from the D, E, and F groups was added to the resin matrix to determine the degree of conversion (DC), biaxial flexural strength (BFS), the flexural modulus (FM), and surface roughness after an abrasive challenge (RA). A group with silanized barium glass particles was tested as a control. The data were submitted to ANOVA/Tukey's test (DC, BFS, and RA), and the Kruskal-Wallis test (FM) (alpha = 0.05). BFS values varied between 83 and 142 MPa, and the CN_ab group presented a similar value (123 MPa) to the control group. FM values varied between 3.6 and 8.7 GPa (CN_ab and CN_nf groups, respectively), with a significant difference found only between these groups. RA did not result in significant differences. The use of calcium nitrate solution as a receptor, together with ab initio functionalization formed particles with larger surface areas. Higher BFS values were observed for the material containing DCPD particles with a higher surface area. In general, the DC, FM, and RA values were not affected by the variables studied.


Assuntos
Polímeros/química , Resinas Compostas , Resistência à Flexão
16.
Oral Health Prev Dent ; 18(1): 747-756, 2020 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-32895658

RESUMO

PURPOSE: This in vitro study evaluated the effectiveness of polyacrylic acid as an acid etchant similar to phosphoric acid and its effect on the microtensile bond strength of self-adhesive resin cement to enamel. MATERIALS AND METHODS: Ninety Te-Econom Plus resin blocks (11 x 4 mm) were cemented onto bovine enamel and distributed into 10 groups according to the surface treatments (no surface treatment; etching with 37% phosphoric acid; etching with 20% polyacrylic acid; etching with 37% phosphoric acid + dental adhesive, and etching with 20% polyacrylic acid + dental adhesive) and the self-adhesive resin cements used (RelyX U200 and MaxCem Elite) (n = 9). After bonding, the specimens were sectioned into sticks, subjected to thermocycling (5760 cycles, 5°C and 55°C) and microtensile bond strength testing (n = 6). Images of representative specimens were obtained using a scanning electron microscope. Enamel penetration evaluation of different surface treatments was analysed by confocal laser scanning microscopy (n = 3). Data on bond strength were subjected to 2-way ANOVA and Tukey's least significant difference test (α = 0.05). RESULTS: Both 37% phosphoric acid and 20% polyacrylic acid yielded the same microtensile bond strength between self-adhesive resin cement and enamel, independent of the application of dental adhesives (p > 0.05). MaxCem Elite showed higher bond strength values than RelyX U200 just for the 20% polyacrylic acid group (p = 0.001). CONCLUSION: Acid pre-conditioning of dental enamel may influence the bond strength of self-adhesive resin cement to enamel, and 20% polyacrylic acid showed efficacy similar to that of 37% phosphoric acid.


Assuntos
Colagem Dentária , Cimentos de Resina , Condicionamento Ácido do Dente , Resinas Acrílicas , Animais , Bovinos , Resinas Compostas , Cimentos Dentários , Esmalte Dentário , Análise do Estresse Dentário , Teste de Materiais , Microscopia Eletrônica de Varredura , Propriedades de Superfície , Resistência à Tração
17.
Oral Health Prev Dent ; 18(1): 783-791, 2020 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-32895662

RESUMO

PURPOSE: This study evaluated repair protocols of a non-aged and aged bulk-fill composite in terms of bond strength and leakage. MATERIALS AND METHODS: Ninety-six bulk-fill resin specimens were constructed; half were submitted to thermocycling. Specimens were divided into six groups (n = 16) according to the repair treatments: CG: no repair (control group); Ad: adhesive; DbAd: abrasion with diamond bur + adhesive; SbAd: sandblasting + adhesive; DbSiAd: abrasion with diamond bur + silane + adhesive; and SbSiAd: sandblasting + silane + adhesive. Resin blocks were bonded to the treated surfaces to simulate repair, and the specimens were submitted to microtensile bond strength testing. The failure area was evaluated under a stereomicroscope (40X magnification), and leakage after specimen immersion in silver nitrate solution for 24 h was evaluated under a microscope (200X magnification). Three-way ANOVA (surface treatment, chemical agent, aging) and Tukey's test were performed. RESULTS: Ad and DbAd groups showed the lowest bond strengths, while Ad was the only group negatively influenced by aging. The other groups were statistically similar to the CG in both conditions. All groups exhibited leakage, but groups without silane presented a greater percentage of leakage, mainly when diamond burs were used. Thermocycling did not influence leakage, nor did surface treatment in groups with silane. CONCLUSION: For composite repair, the use of silane is recommended, mainly when diamond burs are used as a mechanical surface treatment.


Assuntos
Resinas Compostas , Colagem Dentária , Teste de Materiais , Silanos , Propriedades de Superfície , Resistência à Tração
18.
J Oral Sci ; 62(4): 430-434, 2020 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-32863318

RESUMO

Perception of tooth shades is subjective and not rated exactly the same by different individuals. In terms of dental esthetics, chairside individualization of dental restorations might help to improve patient satisfaction. This investigation aimed to validate the practicability of a chairside approach for staining resin-based composite restorations. Thirteen inexperienced and 13 experienced participants were recruited to first individualize two CAD/CAM resin-based composite crowns in randomized order with light-curing characterization material using two reference crowns as templates. They then evaluated the characterization procedure. The processing times were recorded, and the clinical quality of the individualized crowns was evaluated by two blinded master dental technicians. Of the 52 crowns examined, 90.4% were assessed as suitable for insertion; there was no difference in quality attributable to the different degrees of experience of the operators. The average time required for characterization of the second crown was significantly shorter than for the first crown (30.9/43.0 min), indicating that the procedure can be implemented using a chairside approach. Among the operators, 80.8% said they would use the individualization technique and staining material again. Chairside staining of CAD/CAM resin-based composite restorations with light-curing characterization materials is practicable and can be recommended for both experienced and inexperienced users.


Assuntos
Porcelana Dentária , Planejamento de Prótese Dentária , Cerâmica , Resinas Compostas , Desenho Assistido por Computador , Coroas , Materiais Dentários , Humanos
19.
Braz Oral Res ; 34: e105, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32876118

RESUMO

The aim of this research was to evaluate the influence of MDP (10-methacryloyloxydecyl dihydrogen phosphate) concentration and application mode of experimental adhesives on microshear bond strength (µSBS) to dentin after storage in distilled water at 37°C for 24h and 6 months. Five experimental adhesives were prepared with: CQ, DABE, BHT, ethanol, HEMA, TEGDMA, Bis-EMA, UDMA, and Bis-GMA. Concentrations of 0 wt%, 3 wt%, 9 wt%, 12 wt% or 15 wt% of MDP were added to their composition. The adhesives were applied to flat dentin surfaces in etch-and-rinse or self-etching modes. Cylindrical molds filled with light-cured composite resin were placed above the dentin. The specimens were stored in distilled water at 37oC for 24h or 6 months and submitted to µSBS testing. The adhesives were also submitted to pH analysis. The data were analyzed by one-way ANOVA, three-way ANOVA and Tukey's test (α = 5%). All the adhesives used in the etch-and-rinse mode showed significantly higher bond strength than the adhesives applied in the self-etching approach. The 9 wt% adhesive showed the highest bond strength values, and 3 wt% was most stable after storage. A strong negative correlation between MDP concentration and pH was observed. It was concluded that the formulations with low concentrations of MDP (up to 9 wt%) showed better results for bond strength and bond strength degradation over time.


Assuntos
Colagem Dentária , Adesividade , Resinas Compostas , Cimentos Dentários , Dentina , Adesivos Dentinários , Teste de Materiais , Cimentos de Resina , Resistência à Tração
20.
Braz Oral Res ; 34: e111, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32876124

RESUMO

This study evaluated the effect of selective carious tissue removal on the fracture strength and failure mode of composite restorations in molars presenting only the buccal cusps. Deep cavities were prepared on the occlusal surface, and the lingual cusps were removed. Carious lesions in the middle of the pulpal wall were artificially induced with acetic acid (pH = 4.5) for 35 days. The demineralized dentin was left intact or was completely removed prior to restoration with a bulk-fill composite (n = 10). Images of the specimens were obtained by optical coherence tomography (OCT) before and after the caries induction/removal. The mechanical resistance to fracture by axial compressive loading and the failure type and extension were determined. The pulpal wall/composite interface of the fractured specimens was analyzed by OCT. The data were analyzed for significance with t-tests (α = 0.05). The deepest cavities and a more frequent occurrence of pulpal exposure were observed more often for non-selective carious tissue removal. The protocol of carious tissue removal did not affect the fracture strength (p = 0.554). An increased occurrence of catastrophic failures involving the roots was observed for non-selective carious tissue removal. Some occurrences of restoration displacement or cracks throughout the resin-dentin were observed only for the selective carious tissue approach. Selective carious tissue removal is a feasible approach to extensively damaged teeth since it reduced the occurrence of pulpal exposure and root fractures, without compromising the fracture strength.


Assuntos
Fraturas Ósseas , Resinas Compostas , Cárie Dentária , Restauração Dentária Permanente , Humanos , Dente Molar
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