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1.
J Contemp Dent Pract ; 21(1): 51-55, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32381801

RESUMO

AIMS AND OBJECTIVES: New techniques are being developed to invent zirconia with high translucency and better esthetics leading to the development of several brands of monolithic zirconia. The aim of this study is to compare the translucency of three brands of zirconia available for the fabrication of monolithic restorations. MATERIALS AND METHODS: An in vitro study was designed to compare the translucency of three brands of zirconia available for the fabrication of monolithic restorations: Zirlux Zirconia (Vivadent Ivoclar), Zenostar Zr Translucent Zirconia (Weiland), and BruxZir Zirconia (Glidewell). All specimens were prepared to 0.5 mm thickness. Thirty zirconia specimens from each material were finished and polished. After drying, specimens were fired according to the manufacturers' recommendations. A spectrophotometer (Color i5) was used for the translucency test. Each specimen was presented at the view port permitting the light to hit the center of the specimen. Results were saved into the software until all measurements were completed. The data were then transferred to an Excel sheet where translucency parameters were calculated. The one-way analysis of variance (ANOVA) test and the post hoc Bonferroni test were performed to analyze the results. RESULTS: The one-way ANOVA test revealed that there was a statistically significant difference between the groups. This study showed lower translucency of BruxZir in comparison to Zenostar and Zirlux when tested under standardized conditions. CONCLUSION: There is a statistically significant difference in the translucency between the different brands of zirconia available for monolithic restoration fabrication. CLINICAL SIGNIFICANCE: Different brands of zirconia have different degrees of translucency. Material selection should be customized in each case.


Assuntos
Cerâmica , Materiais Dentários , Estética Dentária , Teste de Materiais , Zircônio
2.
J Contemp Dent Pract ; 21(2): 114-118, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-32381812

RESUMO

AIM: Newer zirconia materials may have greater strength degradation under cyclic fatigue with increased yttria and cubic content. The purpose of this study was to evaluate the flexural strength (FS) degradation of newer zirconia materials compared to more traditional tetragonal zirconia materials. MATERIALS AND METHODS: The following materials were tested: two 3 mol% yttria-stabilized tetragonal zirconia polycrystal (3Y-TZP) materials (Lava Plus, 3M ESPE; Katana ML, Kuraray), one 4 mol% partially stabilized zirconia (4Y-PSZ) material (Katana STML, Kuraray), two 5 mol% partially stabilized zirconia (5Y-PSZ) materials (Katana STML, Kuraray; Lava Esthetic, 3M ESPE), and one lithium disilicate material (IPS e.max CAD LT, Ivoclar Vivadent). Thirty beams were milled for each ceramic material with final dimensions of 4.0 × 1.3 × 18.0 mm after sintering or crystallization. Each specimen was placed on a 3-point bend test device on a universal testing machine (Instron, Norwood, MA). Flexural strength was determined on 10 beam specimens per group with a central load applied until fracture. Flexural fatigue strength was then measured on the remaining 20 beam specimens per group using the staircase method for 6,000 cycles at 2 Hz. Data were analyzed with one-way ANOVAs/Tukey post hoc tests (α = 0.05). RESULTS: A significant difference was found between groups (p < 0.001) per property. The 3Y-TZP zirconia materials had the greatest flexural and flexural fatigue strength. The cubic containing zirconia materials performed more moderately. The lithium disilicate material had the lowest strength values. The percent degradation in flexural fatigue strength of the 3Y-TZP zirconia materials was less than the 5Y-PSZ, Katana UTML, and the 4Y-PSZ, Katana STML, cubic containing materials, but similar to the 5Y-PSZ cubic containing material, Lava Esthetic. CONCLUSION: The amount of strength degradation was material dependent, with the 4Y-PSZ or 5Y-PSZ cubic containing zirconia materials demonstrating greater or similar strength degradation compared to the primarily tetragonal 3Y-TZP zirconia materials. CLINICAL SIGNIFICANCE: The differences in FS degradation between cubic containing materials and traditional zirconia materials could significantly impact the long-term success of these newer materials. Clinicians should be aware that these cubic containing materials may perform differently long-term than the very strong traditional 3Y-TZP materials and to follow manufacturer instructions on required material thickness and indications for use to prevent premature failure of the restoration.


Assuntos
Materiais Dentários , Resistência à Flexão , Estética Dentária , Teste de Materiais , Zircônio
3.
Indian J Dent Res ; 31(2): 236-240, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32436903

RESUMO

Aims: Considering new ceramic systems, doubts about the appropriate combination of ceramics and cement are common. Settings and Design: To evaluate the influence of the elastic modulus (E) of cement agents associated with different indirect veneers on the stress distribution using finite element analysis. Methods and Materials: The finite element analysis was applied to evaluate the stress distribution on the structures. For that, a computer-aided design software was used for a three-dimensional (3D) modeling of an upper central incisor with preparation for an indirect veneer. The model was imported into the analysis software in STEP (Standard for Exchange of Product data) format. Tetrahedral elements formed the mesh. Solids were considered isotropic, linearly elastic, homogeneous, and with ideal contacts. Load application (100N, 45°) occurred on the lingual face. Cement agents have their E classified as low, intermediate, and high. The ceramic materials used were a hybrid ceramic, a zirconia reinforced lithium silicate and a lithium disilicate. Results: It was observed that none of the factors significantly influenced the stress concentration in dentine. Groups with high E cementing agent showed the highest stress peaks. The E of restorative material was significant for the stress generated in the veneer, and groups with hybrid ceramic presented more homogeneous stress results. Conclusions: The higher E of the cement agent and the ceramic, the higher the stress concentration, suggesting that hybrid ceramic associated with low elastic modulus resinous cement has superior biomechanical behavior.


Assuntos
Porcelana Dentária , Incisivo , Cerâmica , Cimentos Dentários , Materiais Dentários , Análise do Estresse Dentário , Análise de Elementos Finitos , Teste de Materiais , Estresse Mecânico
4.
Stomatologiia (Mosk) ; 99(2): 79-84, 2020.
Artigo em Russo | MEDLINE | ID: mdl-32441080

RESUMO

OBJECTIVE: Characteristics of the adhesion of yeast fungi and oral bacteria of various types in vitro to samples of polymeric materials for fixed structures of dental prostheses, obtained using various technologies: adjective digital 3D printing and traditional methods. MATERIAL AND METHODS: Conducted model experiments on the adhesion of bacterial (including the main periodontopic-pathogenic species - P. gingivalis, P. intermedia, etc.) and fungal pathogens (C. albicans) to standard samples of polymer materials NextDent C & B Micro Filled Hybrid («NextDent¼, Netherlands), Detax Freeprint temp UV («Detax¼, Germany), obtained by digital additive 3D printing technology, and Luxatemp Automix Plus («DMG¼, Germany) and Acrytemp («Zhermack¼, Italy) - by the traditional method as a control. Removal of adhering microbes from the material was carried out using an ultrasound machine (exposure time 10 minutes, power 60 kHz). RESULTS: The dependence of the degree of microbial adhesion on the nature of the material and processing technology (3D printing, milling) was established. The materials of NextDent C & B Micro Filled Hybrid and Detax Freeprint temp UV showed high resistance to adhesion of clinical isolates of periodontal pathogenic bacteria and C. albicans fungi. CONCLUSION: The lowest adhesion values for periodontopathogenic species and C. albicans fungi were detected when using samples of materials obtained by 3D printing: NextDent C & B Micro Filled Hybrid and Detax Freeprint temp UV compared to Luxatemp Automix Plus and Acrytemp polymers.


Assuntos
Materiais Dentários , Polímeros , Bactérias , Biofilmes , Candida albicans , Boca
5.
Stomatologiia (Mosk) ; 99(2): 110-113, 2020.
Artigo em Russo | MEDLINE | ID: mdl-32441085

RESUMO

This article provides the current data of the modern literature on the question of the biocompatibility of dental materials, their influence on the local immune homeostasis of the oral cavity; influence of the method of transmission of masticatory load on the tissues and organs of the oral cavity. Thus, when installing the seal, the choice of material, the localization of carious lesions, and when prosthetics - the choice of material of the prosthetic structure and the method of transfer of chewing load is important. It should be understood that the reaction of the mucous membrane can be not only in the area of direct contact with the dental material, but also appear in remote areas of the oral mucosa.


Assuntos
Cárie Dentária , Materiais Dentários , Humanos , Mastigação , Mucosa Bucal
6.
Quintessence Int ; 51(5): 398-404, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32253391

RESUMO

OBJECTIVE: To describe and illustrate the histologic characteristics of luting cement-induced peri-implantitis in the posterior maxilla of a 56-year-old man. CASE PRESENTATION: A dental implant inserted 6 years previously in the maxillary left first premolar region revealed pus and swelling. A periapical radiograph showed severe bone loss around the dental implant, and the presence of surrounding residual particles of luting cement. The implant was removed with its adjacent tissues. The harvested implant was fixed in formaldehyde solution (formalin). A 4-mm fragment of soft tissue and a 6-mm fragment of bone were cut from the implant specimen and submitted for routine processing of hematoxylin-eosin (h&e) slides for histologic analysis. The implant specimen was processed and embedded in glycol methacrylate resin and ground to a thickness of 50 µm for histologic examination. RESULTS: The microscopic examination of the h&e slides showed connective tissue with an inflammatory infiltrate composed of histiocytes, lymphocytes, and plasma cells. There was a fragment of viable bone integrated with the bone graft material. The bone showed evidence of active resorption by osteoclasts in Howship lacunae. The implant sections showed trabecular bone with lamellar structure in the apical portion. Foreign body, compatible with luting cement, was present in the coronal portion, adjacent to the threads of the implant, as well as osteoclasts in Howship lacunae. CONCLUSION: This report, documenting a case of peri-implantitis associated with excess cement extrusion, revealed that that the bone loss was associated with an inflammatory infiltrate. Additional studies focusing on the histopathologic characteristics of peri-implantitis could help to increase the knowledge of peri-implant disease to shed light on prevention and treatment.


Assuntos
Implantes Dentários , Peri-Implantite , Cimentos Dentários , Materiais Dentários , Humanos , Masculino , Maxila , Pessoa de Meia-Idade
7.
Braz Oral Res ; 34: e020, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32236317

RESUMO

This in vitro study aimed to assess the effects of different pretreatments used to adapt glass-fiber posts cemented to root canals with different resin cements, regarding porosity percentage and bond strength. Twelve bovine incisor roots were prepared with Largo drills. After post space preparation, the specimens were randomized into two types of pretreatment groups (n = 3): water-wet bonding and ethanol-wet bonding. After the post were cemented, the roots were stored in 100% humidity at room temperature for 7 days. The samples were scanned by microcomputed tomography (micro-CT). Images were reconstructed by NRecon software, and CTAn software was used to analyze the porosity percentage (%) at the luting interface. Evaluation of the push-out bond strength was performed by serially cutting the roots, and submitting the slices to testing. Additionally, the resin cement post-gel shrinkage values (%) were measured using the strain-gauge method (n = 10). Data were analyzed by two-way ANOVA, Tukey's test and Student's t test (a = 0.05). The roots prepared with ethanol-wet bonding using RelyX™ U200 had significantly lower porosity in the coronal and apical thirds (p < 0.05). The group prepared with ethanol-wet bonding using RelyX™ ARC presented better bond strength results in the coronal and apical thirds (p < 0.05). RelyX™ ARC (0.97%) produced a higher post-gel shrinkage value than RelyX™ U200 (0.77%). Canals pretreated with ethanol-wet bonding presented better outcomes in regard to porosity percentage and push-out bond strength.


Assuntos
Adesivos Dentinários/farmacologia , Etanol/farmacologia , Técnica para Retentor Intrarradicular , Cimentos de Resina/química , Raiz Dentária/efeitos dos fármacos , Animais , Bovinos , Colagem Dentária , Materiais Dentários/química , Cavidade Pulpar , Vidro , Teste de Materiais , Porosidade , Irrigantes do Canal Radicular/química , Microtomografia por Raio-X
8.
Oral Health Prev Dent ; 18(2): 153-159, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32238987

RESUMO

PURPOSE: The air-particle-abrasion on zirconia in the gingival area of connectors and pontics in fixed partial dentures appears to increase fracture resistance. This study evaluated 'in situ' biofilm formation on the zirconia surface after different air-particle-abrasion protocols. MATERIALS AND METHODS: Ninety sintered blocks (5 × 5 × 2 mm) of yttrium partially stabilised zirconia (Y-TZP) were obtained and randomised among nine groups according to the factors 'type of particle' (Alumina 50 and 110 µm; Cojet and Rocatec) and 'pressure' (2.5 and 3.5 bar) used for sandblasting for 10 s. The surface roughness (Ra/Rz) was measured before and after sandblasting. For the in-situ analyses, custom-made removable intraoral devices n = 10 with one sample of each group attached to the buccal area were used by volunteers for 8 h at night. The specimens were analysed under confocal microscopy to quantify both biovolume and thickness of the initial biofilm formed. One-way analysis of variance (ANOVA) and Dunnett's tests were performed (5%). RESULTS: The roughness values ranged from 0.05 to 0.39 µm for Ra and from 0.35 to 2.11 µm for Rz, p = 0.00. Mean biofilm thickness ranged from 0.06 and 0.54 µm (p = 0.005), while the biovolume values were between 0.02 and 0.61 µm3/µm2 (p = 0.002). Values statistically significant for biofilm thickness and biovolume were found in groups sandblasted with Rocatec using 3.5 bar. CONCLUSION: In order to increase the fracture resistance of zirconia fixed partial dentures (FPDs), the air particle abrasion of zirconia with SiO2 (110 µm/3.5 bar), in the gingival area of connectors and pontics, should be avoided.


Assuntos
Colagem Dentária , Dióxido de Silício , Biofilmes , Materiais Dentários , Humanos , Teste de Materiais , Microscopia Eletrônica de Varredura , Propriedades de Superfície , Zircônio
9.
Rev. cient. odontol ; 8(1): e010-e010, ene.-abr. 2020. tab.
Artigo em Espanhol | LILACS, LIPECS | ID: biblio-1095508

RESUMO

El presente trabajo busca realizar una revisión de la literatura para dar a conocer al personal ocupacionalmente expuesto a radiaciones ionizantes las ventajas y propiedades del concreto simple y la baritina para justificar su aplicación como materiales de blindaje en el diseño y construcción de muros en áreas donde se utilizan rayos X de uso odontológico, ya que estos, al no ser utilizados de manera segura, pueden tener efectos perjudiciales en la salud de las personas. En este trabajo también se describen las características generales de los rayos X que los hacen nocivos para la salud del personal ocupacionalmente expuesto, así como del público en general, por lo que surge en este punto el término de atenuación. Se encontró poca información sobre el tema, por lo que se desarrolló la relación existente entre ambos materiales y su importancia para dar información que pueda ser útil a todas las personas. Se concluyó que ambos materiales tienen la capacidad de bloquear y reducir la intensidad de la radiación, ya que el concreto actúa como un absorbente para reducir los efectos biológicos de la radiación y la baritina funciona como blindaje basado en el coeficiente de atenuación, por lo que ambos ofrecen una mayor resistencia y, al ser aplicados en conjunto, brindan una mayor protección para aquellas personas que puedan estar expuestas a rayos ionizantes. (AU)


The safety of the use of radiation in odontology must be guaranteed in order to avoid adverse effects to the health of dental staff and patients. The present study is a review of the literature on exposure to ionizing radiations and the advantages and properties which simple concrete and barite provide as shielding material in wall design and construction in areas of odontology in which X-rays are used. The general characteristics of X-rays which make them harmful to exposed workers and the general public are described. An attenuation coefficient is the fraction of an x-ray beam that is absorbed or scattered per unit thickness of the absorber. There is little information on this subject, however, it was found that both concrete and barite are able to block and reduce the intensity of radiation, with concrete acting as an absorbent to reduce the biological effects of radiation and barite acting as a shield. Based on the coefficient of attenuation these two materials provide greater resistance and their combined use allows greater protection against exposure to ionizing rays. (AU)


Assuntos
Humanos , Raios X , Cimentos Dentários , Materiais Dentários
10.
Indian J Dent Res ; 31(1): 138-144, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32246697

RESUMO

Background: Laboratory reports show that fiber-reinforced composites have improved fracture resistance over traditional composites. However, limitations in the biomechanics of tests to evaluate the fracture resistance of fiber-reinforced composites need to be considered for accurate clinical applications. Aim: To assess the fracture resistance of particulate filler composites, glass fiber-reinforced composites, and polyethylene-fiber reinforced composites by analyzing the different fracture types and failure patterns. Materials and Methods: A standardized incisal (Group I) and mesioincisal fractures (Group II) were prepared on human maxillary central incisors. The test samples were further subdivided according to the restorative material used; particulate filler composites (Filtek Z 250), glass fiber-reinforced composites (fibre splint), and polyethylene-reinforced composites (Ribbond). The type of fractures was evaluated under the stereomicroscope and the failure patterns were analyzed using the graphical output from Universal Testing Machine. Statistical Analysis: The Chi-square test of association was used to test the association between fiber-reinforced composites and fracture resistance of tooth restoration complex. Results: No statistical association was observed between fiber-reinforced composites to the type of fractures in both incisal (P = 0.29) and mesioincisal restoration (P = 0.27). A significant association was observed between the fiber-reinforced composites to the failure patterns in both the incisal (P = 0.005) and mesioincisal restoration (P = 0.007). Conclusion: The glass and polyethylene fiber-reinforced composites showed improved fracture resistance properties than the traditional particulate filler composites in both incisal and mesioincisal restorations.


Assuntos
Resinas Compostas , Fraturas dos Dentes , Materiais Dentários , Falha de Restauração Dentária , Restauração Dentária Permanente , Análise do Estresse Dentário , Vidro , Humanos , Teste de Materiais , Estresse Mecânico
11.
Am J Dent ; 33(2): 59-63, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32259408

RESUMO

PURPOSE: To evaluate Streptococcus mutans biofilm formation over different restorative dental materials. METHODS: Using a bioreactor over 72 hours, four commercially available ceramics were evaluated: IPS E-max Press, IPS E-max CAD, Lava Ultimate CAD-CAM, Vita Enamic and two resin composites (SR Nexco Paste and Brilliant NG). The results were evaluated using atomic force microscopy and confocal microscopy, the biofilm was stained and the arbitrary fluorescence units (AFU) quantified. RESULTS: The results showed that IPS E-max CAD had the lowest roughness values (4.29±1.79 nm), while the highest values were observed for Vita Enamic discs ( (77.13±17.35 nm). Analysis of S. mutans biofilm formation by AFU revealed lower values for IPS E-max CAD (6.77±1.67 nm); the highest values were found for Lava Ultimate (79.99±22.23 nm). Regarding the composite groups, SR Nexco Paste showed roughness values of 15.07±2.77 nm and lower arbitrary fluorescence units of 30.92±12.01 nm than Brilliant NT. There was a correlation between the surface roughness of ceramics and composite with S. mutans biofilm formation. CLINICAL SIGNIFICANCE: The adhesion of oral bacteria to restorative dental materials plays a key role in the success of dental treatment; the surface roughness influences the S. mutans biofilm formation.


Assuntos
Materiais Dentários , Streptococcus mutans , Biofilmes , Cerâmica , Desenho Assistido por Computador , Porcelana Dentária , Teste de Materiais , Propriedades de Superfície
12.
Stomatologiia (Mosk) ; 99(1): 18-26, 2020.
Artigo em Russo | MEDLINE | ID: mdl-32125297

RESUMO

The problem of hard dental tissues diseases treatment, the high need of the population to replace poor-quality restorations, as well as the constant dentistry market updating make it necessary to evaluate dental restorations using objective criteria. The purpose of this article is to present the new FDI criteria for evaluating aesthetic restorations and explanations of their use, as well as a quality comparative assessment of restorations made from various light-curing composites. The clinical part of the work was to assess the restoration quality III and IV Black classes. A total of 33 restorations were made. All patients had good oral hygiene (OHIS <0.6±0.02) was characterized by the absence of inflammation or mild inflammation of the gums (GI <0.66±0.04) and high intensity of the carious process (KPU=12.2±0.8). The analysis of the obtained data from the pilot clinical study leads to the following conclusions: new advanced FDI criteria provide complete information about quality of the restorations and can be recommended for evaluating the clinical efficacy of various materials; this evaluation system of restorations is flexible, it can change over time and it allows you to follow the new trends in materials science and restoration methods as accurately as possible.


Assuntos
Resinas Compostas , Restauração Dentária Permanente , Cor , Materiais Dentários , Falha de Restauração Dentária , Estética Dentária , Seguimentos , Humanos
13.
J Prosthet Dent ; 123(4): 647.e1-647.e7, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32115217

RESUMO

STATEMENT OF PROBLEM: Artificial denture teeth made of polymethyl methacrylate (PMMA) resin have good adhesion to the denture base but are relatively soft and have limited wear resistance during function. PURPOSE: The purpose of this in vitro study was to evaluate the influence of the addition of 2 inorganic nanofillers on the flexural strength, maximal displacement, elastic modulus, Isolde impact resistance, and Brinell hardness of acrylic resin denture teeth. MATERIAL AND METHODS: Heat polymerizing polymethyl methacrylate resin was mixed with silanized silica or silanized feldspar in concentrations of 5 wt%, 10 wt%, and 15 wt%. The first test was conducted after 24 hours of storage in laboratory conditions, and the second assessment was conducted after 3 months of storage in distilled water at 37 °C. The Brinell hardness was evaluated, and the elastic modulus and maximal displacement at fracture were calculated. The flexural strength and Isolde impact resistance were measured with a 3-point flexural test. Acrylic resin specimens without filler addition were used as a control group. Statistical analysis included 2-way ANOVA for independent variables (α=.05) and the Student t test for time-dependent changes (α=.05). These were performed with Statistica 12 software. RESULTS: The acrylic resin specimens modified with the addition of silanized feldspar had significantly higher Brinell hardness, elastic modulus, maximal displacement, and flexural strength and also had no adverse effect on Isolde impact resistance compared with the conventional acrylic resin. Silica filler increased the Brinell hardness and elastic modulus of acrylic resins but significantly reduced the flexural strength and Isolde impact resistance.


Assuntos
Polimetil Metacrilato , Dióxido de Silício , Silicatos de Alumínio , Materiais Dentários , Bases de Dentadura , Dentaduras , Humanos , Teste de Materiais , Maleabilidade , Compostos de Potássio , Estresse Mecânico , Propriedades de Superfície
14.
Minerva Stomatol ; 69(1): 21-26, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32181608

RESUMO

BACKGROUND: Ultrasonic devices have a lot of dental application specially in hygiene and surgery. However there are some disadvantages like cut slowness and heat production. Prosthodontics application is less investigated. In particular the heat production could be an important factor for the clinician. In fact more than 5.5 °C temperature increasing could determine pulp necrosis during tooth preparation. The aim of this study is to investigate the increasing of temperature during finishing line repositioning and polishing phases using ultrasounds inserts and to verify if it remains within the limit of 5.5 °C. METHODS: A sample of 32 human molars (extracted for periodontal reasons) was selected. The teeth were endodontically treated and prepared with burs in order to obtain a prosthetic round chamfer preparation, leaving the apical portion pervious for inserting the thermocouple probe. Then, they were inserted in plaster cubes up to the cement-enamel junction. A wall has been selected for each tooth for margin repositioning and finishing and prepared with the piezoelectric instrument (Multipiezo Touch with TipHolder DB2, Mectron, Carasco, Genoa, Italy). A mechanical arm was used to standardize the operator-dependent parameters. These parameters were: the pressure exerted on the dental wall, the cutting length and the time required for margin repositioning and finishing. The test phase consisted in a first stage of margin repositioning using an regular ultrasound tip with a diamond grain of 120 micron (DB120, Mectron, Carasco, Italy) (group 1), followed by a second finishing step conducted by a extra fine ultrasound tip with a diamond grain of 60 micron (DB60, Mectron, Carasco, Italy) (group 2). Each test lasted 60 seconds: this was the time that the mechanical arm needed to accomplish 32 rides. During these stages the intrapulpal temperature has been recorded thanks to a thermocouple. The obtained temperature data were analyzed by Kruskal-Wallis test and Mann-Withney post-hoc test, without Bonferroni correction (P<0.001). RESULTS: The average pulpal temperature increase was 4.65 °C with a standard deviation of 0.99 °C for the DB 120 ultrasonic tip and 5.40 °C with a standard deviation of 0.84 °C for the DB 60 ultrasonic tip. However, neither of the instruments reach the medium critical level of 5.5°C reported in the literature, there are some single values who exceed it. There is statistically significant difference using tips with different granulometries within the two groups (P value =0.013). CONCLUSIONS: Ultrasonic tools are very performing to achieve results in repositioning and polishing of prepared tooth. The in-vitro analysis show that the pulp temperature increasing remains within the safe limits literature shows. It is important underline the polishing phase is the most critical and the clinicians have to pay attention to irrigation and pression to avoid pulp damages. Additional clinical studies have to be performed to confirm these results.


Assuntos
Polpa Dentária , Preparo do Dente , Esmalte Dentário , Materiais Dentários , Humanos , Itália
15.
Braz Oral Res ; 34: e017, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32130364

RESUMO

Prevention and health promotion are considered important strategies to control oral diseases. Dental caries is preventable disease and remains the most common chronic disease that affects mainly low income children and still considered the main cause of tooth loss in adulthood in Brazil. The aim of this study is to present a System Dynamics model (SDM) specifically developed with the Stella Architect software to estimate the cost and clinical hours required to control the evolution of dental caries in preschool children in Maringá, Brazil. Two main strategies to control caries were considered in the model: the application of fluoride varnish on teeth presenting white spots, and the use of Atraumatic Restorative Treatment (ART) in cavitated carious lesions without pulp involvement. The parameters used in the model were: number of people covered by a local oral health team = 4,000; number of children up to 5 years = 7% of the population; children's decayed, missing, filled teeth (dmft) index = 2.4; time/cost of 4 applications of fluoride varnish = 5 minutes/US$ 0.716; and time/cost of each ART restoration = 15 minutes/US$ 1.475. The SDM generated an estimated total cost of US$698.00, and a total of 112 clinical hours to treat the population in question. The use of the SDM presented here has the potential to assist decision making by measuring the material and human resources required to prevent and control dental caries at an early age.


Assuntos
Tratamento Dentário Restaurador sem Trauma/economia , Cárie Dentária/economia , Cárie Dentária/terapia , Análise de Sistemas , Brasil , Pré-Escolar , Índice CPO , Tratamento Dentário Restaurador sem Trauma/métodos , Materiais Dentários/economia , Feminino , Fluoretos Tópicos/economia , Humanos , Masculino , Software/normas , Fatores de Tempo
16.
Oper Dent ; 45(3): E114-E123, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32053454

RESUMO

OBJECTIVE: The objective of this study was to evaluate the effect of erosion or erosion-abrasion on bioactive materials and adjacent enamel/dentin areas. METHODS AND MATERIALS: Enamel and dentin blocks (4×4×2 mm) were embedded side by side in acrylic resin, and a standardized cavity (1.2×4×1.5 mm) was prepared between them. Preparations were restored with the following materials: composite resin (Filtek Z350, control); experimental composite containing di-calcium phosphate dihydrate particles (DCPD); Giomer (Beautifil II), high viscosity glass ionomer cement (GIC, Fuji IX); and a resin-modified GIC (Fuji II LC). The specimens were submitted to two cycling models (n=10): erosion or erosion-abrasion. The challenges consisted of five-minute immersion in 0.3% citric acid solution, followed by 60-minute exposure to artificial saliva. Toothbrushing was carried out twice daily, 30 minutes after the first and last exposures to acid. Dental and material surface loss (SL, in µm) were determined by optical profilometry. Data were analyzed with Kruskal-Wallis and Dunn tests (α=0.05). RESULTS: Under erosion, for enamel, only the GIC groups presented lower SL values than Z350 (p<0.001 for Fuji IX and p=0.018 for Fuji II LC). For dentin, none of the materials showed significantly lower SL values than Z350 (p>0.05). For material, the GICs had significantly higher SL values than those of Z350 (p<0.001 for Fuji IX and p=0.002 for Fuji II LC). Under erosion-abrasion, the enamel SL value was significantly lower around Fuji II LC compared with the other materials (p<0.05). No significant differences were observed among groups for dentin SL (p=0.063). The GICs and Giomer showed higher SL values than Z350 (p<0.001 for the GICs and p=0.041 for Giomer). CONCLUSION: Both GIC-based materials were susceptible to erosive wear; however, they promoted the lowest erosive loss of adjacent enamel. Against erosion-abrasion, only Fuji II LC was able to reduce enamel loss. For dentin, none of the materials exhibited a significant protective effect.


Assuntos
Esmalte Dentário , Cimentos de Ionômeros de Vidro , Materiais Dentários , Dentina , Saliva Artificial , Escovação Dentária
17.
Oper Dent ; 45(3): E141-E155, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32053458

RESUMO

OBJECTIVES: This study examined the influence of different light-curing units (LCUs) and exposure times on the microhardness across bulk-fill resin-based composite (RBC) restorations in a molar tooth. METHODS AND MATERIALS: Tip diameter, radiant power, radiant exitance, emission spectra, and light beam profile were measured on two single-emission-peak LCUs (Celalux 3 and DeepCure-S) and two multiple-peak LCUs (Bluephase 20i and Valo Grand). A mold was made using a human molar that had a 12-mm mesial-distal length, a 2.5-mm deep occlusal box, and two 4.5-mm deep proximal boxes. Two bulk-fill RBCs (Filtek Bulk Fill Posterior and Tetric EvoCeram Bulk Fill) were photoactivated for 10 seconds and for 20 seconds, with the light guide positioned at the center of the occlusal surface. Microhardness was then measured across the transverse surface of the restorations. The light that reached the bottom of the proximal boxes was examined. Data were statistically analyzed with the Student t-test, two-way analysis of variance, and the Tukey post hoc test (α=0.05). RESULTS: The four LCUs were different regarding all the tested characteristics. Even when using LCUs with wide tips and a homogeneous beam profile, there were significant differences in the microhardness results obtained at the central and proximal regions of the RBCs (p<0.05). LCUs with wider tips used for 20 seconds produced higher microhardness values (p<0.05). The multiple-peak LCUs produced greater hardness values in Tetric EvoCeram Bulk Fill than did the single-emission-peak LCUs (Celalux 3 and DeepCure-S). Results for the light measured at the bottom of proximal boxes showed that little light reached these regions when the light tip was positioned at the center of restorations. CONCLUSIONS: Curing lights with wide tips, homogeneous light beam profiles, and longer exposure times are preferred when light-curing large MOD restorations. Light curing from more than one position may be required for adequate photopolymerization.


Assuntos
Luzes de Cura Dentária , Cura Luminosa de Adesivos Dentários , Resinas Compostas , Materiais Dentários , Dureza , Humanos , Teste de Materiais , Dente Molar , Polimerização , Propriedades de Superfície
18.
Oper Dent ; 45(3): E156-E166, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32053459

RESUMO

The purpose of this laboratory study was to compare the two-body wear resistance of different restorative materials commonly used for the indirect restoration of posterior teeth. The tested materials, based on ceramic (Imagine Press X, IPS e.max CAD, Milled Celtra Duo, Glaze-Fired Celtra Duo, Vita Mark II) and composite (Enamel Plus HRi, Enamel Plus HRi Bio-Function, Filtek Supreme XTE, Lava Ultimate), were compared with the wear properties of a type III gold alloy (Aurocast 8). Flat samples were prepared with a 6-mm thickness (n=10). Composite samples were tested after a heat polymerization cycle. All samples were exposed to a two-body wear test in a dual axis chewing simulator performing over 120,000 loading cycles. The opposing abrader cusps were fabricated from yttria-stabilized tetragonal zirconia polycrystal. The vertical substance loss (mm) and the volume loss (mm3) were recorded, as was the wear of the antagonist cusp (mm). Mean values were analyzed by one-way analysis of variance. Significant differences among materials were detected. The heat-cured resin-based composite material Enamel Plus Bio-Function and the type III gold alloy demonstrated similar mean values for wear depth and volumetric loss.


Assuntos
Materiais Dentários , Porcelana Dentária , Cerâmica , Resinas Compostas , Esmalte Dentário , Desgaste de Restauração Dentária , Ligas de Ouro , Teste de Materiais , Propriedades de Superfície
19.
Life Sci ; 248: 117460, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32092331

RESUMO

AIM: This study determined the optimum gamma irradiation dosage to sterilize sodium hyaluronate (HY), single-walled carbon nanotubes (SWCNT), multi-walled carbon nanotubes (MWCNT) and CNT functionalized with HY (HY-SWCNT and HY-MWCNT), evaluated the structural integrity of the materials and assessed whether sterilized materials kept biological properties without affecting renal function. MAIN METHODS: Materials were submitted to dosages of 100 gγ to 30 Kgγ and plated onto agar mediums for colony forming units (CFUs) counting. Sterilized samples were inoculated with 107Bacillus clausii, submitted again to gamma irradiation, and plated in agar mediums for CFUs counting. Scanning electron microscope was used for structural evaluation of sterilized materials. Tooth sockets of rats were treated with sterilized materials for bone formation assessment and renal function of the animals was analyzed. KEY FINDINGS: The optimum gamma dosage for sterilization was 250 gγ for HY and 2.5 Kgγ for the other materials without meaningful structural changes. Sterilized materials significantly increased bone formation (p < 0.05) and they did not compromise renal function and structure. SIGNIFICANCE: Gamma irradiation efficiently sterilized HY, SWCNT, MWCNT, HY-SWCNT and HY-MWCNT without affecting structural aspects while maintaining their desirable biological properties.


Assuntos
Materiais Dentários/efeitos da radiação , Raios gama , Ácido Hialurônico/efeitos da radiação , Nanotubos de Carbono/efeitos da radiação , Osteogênese/efeitos dos fármacos , Alvéolo Dental/efeitos dos fármacos , Animais , Bacillus clausii/efeitos da radiação , Contagem de Colônia Microbiana , Materiais Dentários/química , Materiais Dentários/farmacologia , Humanos , Ácido Hialurônico/química , Ácido Hialurônico/farmacologia , Testes de Função Renal , Masculino , Dente Molar/cirurgia , Nanotubos de Carbono/química , Nanotubos de Carbono/ultraestrutura , Ratos , Ratos Wistar , Esterilização/métodos , Extração Dentária/métodos , Alvéolo Dental/microbiologia , Alvéolo Dental/fisiologia , Alvéolo Dental/cirurgia , Cicatrização/efeitos dos fármacos
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