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1.
Gen Dent ; 69(1): 31-36, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33350953

RESUMEN

The objective of this study was to compare techniques of different methods of obtaining centric relation to verify which technique generates the greatest reproducibility of the centric relation. The PubMed/MEDLINE, Cochrane Library, SciELO, Scopus, and Web of Science databases were searched for articles published up to May 15, 2018. The search terms were combinations of "dental centric relation" with each of the following terms (individually): "reproducibility of findings"; "jaw relation record"; "chin point"; "gothic arch"; "bimanual manipulation"; "swallowing"; and "jig." The inclusion criteria included clinical studies in English that had to compare at least 2 techniques representing different methods for obtaining centric relation (based on the reproducibility of the centric relation) in individuals without temporomandibular dysfunction; and studies performed in individuals with complete or nearly complete dentition or complete edentulism. Methods (techniques) included in this study were guided methods (chin point guidance and bimanual manipulation); graphic methods (intraoral and extraoral gothic arch tracing); and physiologic methods (swallowing and tongue retrusion along the palate). A total of 1638 articles were identified. After the inclusion and exclusion criteria were applied, 7 articles were included in this review. None of the reviewed studies evaluated edentulous individuals. Two articles compared physiologic methods with guided methods; one concluded that the swallowing technique generates greater variability than guided methods, and the other concluded that there was no difference between the swallowing technique and chin point guidance. Of 5 articles comparing intraoral gothic arch tracing with guided methods, 2 showed similar results between different methods, 2 showed superior results for gothic arch tracing, and 1 showed superior results for the guided methods. Based on the guided methods and swallowing technique, it is not possible to conclude which technique can generate the greatest reproducibility of the centric relation. It is possible to suggest that in most cases intraoral gothic arch tracing is superior or equivalent when compared to guided methods.


Asunto(s)
Boca Edéntula , Relación Céntrica , Humanos , Registro de la Relación Maxilomandibular , Reproducibilidad de los Resultados
2.
J Prosthet Dent ; 124(6): 815.e1-815.e7, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-33268070

RESUMEN

STATEMENT OF PROBLEM: Exposure of silicone prostheses to environmental factors can alter their properties, affecting longevity. However, whether nonthermal plasma (NTP) can prevent these alterations is unclear. PURPOSE: The purpose of this in vitro study was to evaluate the surface roughness (Ra), sorption, solubility, and color stability (ΔE00) of the MDX4-4210 and A-120 silicones, with and without NTP treatment in accordance with an independent analysis of the use of 2 pigmentations. MATERIAL AND METHODS: One hundred sixty specimens were fabricated and distributed into 16 groups (n=10) as per the silicone, pigmentation, and NTP coating. The NTP was applied, and the Ra, sorption, solubility, and ΔE00 were evaluated before and after accelerated aging. ANOVA was used, and the HSD Tukey test was applied (α=.05). RESULTS: NTP generated an increase in roughness after aging, regardless of pigmentation or silicone. A-120 silicone without NTP showed a reduction in roughness after aging, regardless of pigmentation. For sorption and solubility, the bronze pigmentation (for A-120 and MDX4-4210) presented the smallest results after NTP treatment. For MDX4-4210 with pink pigmentation and NTP, sorption decreased and solubility increased. For A-120 with pink pigmentation and NTP, sorption and solubility increased. Sorption was reduced in all situations, except for A-120 with pink pigmentation, which increased. Regardless of the silicone used, solubility was reduced after NTP for bronze pigmentation. For A-120 and MDX4-4210 with pink pigmentation and NTP, the solubility increased. For both pigmentations, the NTP treatment promoted lower color alteration only for the A-120 silicone after accelerated aging (within the acceptability threshold). CONCLUSIONS: The NTP protocol of this study, which was applied to facial silicones, generated inconsistent results between the evaluated properties. Therefore, the NTP protocol used does not seem to be ideal for the treatment of silicone surfaces after aging.

3.
Gen Dent ; 68(6): 56-59, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33136047

RESUMEN

The aim of this study was to evaluate the flexural strength and Knoop microhardness of the polymethyl methacrylate (PMMA) used in dental prostheses after receiving therapeutic radiation doses of 50 and 70 Gy. Thirty-six acrylic resin plates measuring 65.0 × 10.0 × 3.3 mm were fabricated and polymerized using a microwave. The specimens were randomly divided into 3 groups (n = 12): group 1, which received no radiation; group 2, which received 1 fractioned dose of 2 Gy per day, 5 days per week, for 5 weeks, totaling 50 Gy; and group 3, which received 1 fractioned dose of 2 Gy per day, 5 days per week, for 7 weeks, totaling 70 Gy. All specimens remained in ballistic gel at a temperature of 37°C throughout the study. Afterward, the specimens underwent flexural strength and Knoop microhardness tests. All data were analyzed using analysis of variance and Tukey post hoc test (P < 0.05). For flexural strength, there was a statistically significant difference between groups 1 and 2 (P = 0.012) and between groups 1 and 3 (P = 0.048). For Knoop microhardness, there was a difference between groups 1 and 2 (P = 0.001) and between groups 1 and 3 (P = 0.006). For both flexural strength and microhardness, groups 2 and 3 showed greater values than group 1. Therapeutic radiation doses of 50 and 70 Gy increased the flexural strength and Knoop microhardness of PMMA used in dental prostheses.

4.
J Adhes Dent ; 22(5): 531-538, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33073784

RESUMEN

PURPOSE: To evaluate the roughness, surface energy, and the bond strength of lithium disilicate yielded by two different types of nonthermal plasma (NTP), oxygen- or argon-based, compared to the conventional method. MATERIALS AND METHODS: Ninety-three lithium disilicate (IPS e.max Press) samples were divided into 3 groups: HF (hydrofluoric acid group); ONTP (oxygen-based NTP group); ANTP (argon-based NTP group). Surface energy and roughness analyses were performed before and after surface treatment, and bond strength testing was performed before and after 5000 thermocycles. Scanning electron microscopy (SEM) was used to characterize the surface treatments. Data were submitted to ANOVA and Bonferroni's test with statistical significance set at 5%. RESULTS: The ONTP group presented the highest surface energy values, followed by ANTP and HF. In addition, the ONTP group had higher surface roughness. SEM revealed exposed lithium disilicate crystals in the HF group, but a homogeneous film coverage in both NTP groups. Regarding bond strength, ANTP presented statistically significantly higher values than the other groups before thermocycling, and statistically significantly lower values than the other groups after thermocycling. The HF and ONTP groups presented statistically similar values after thermocycling. CONCLUSION: The bond strength of resin cement to lithium disilicate obtained after oxygen-based NTP was comparable with that obtained after conventional hydrofluoric acid treatment.


Asunto(s)
Recubrimiento Dental Adhesivo , Cementos de Resina , Cerámica , Porcelana Dental , Propiedades de Superficie
5.
PLoS One ; 15(10): e0240116, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33044989

RESUMEN

The aim of this study was to evaluate the effect of disinfectants on the biofilm of Staphylococcus aureus and Staphylococcus epidermidis formed on the acrylic surface of ocular prostheses. In this study, 396 acrylic specimens were manufactured (50% for Staphylococcus epidermidis, and 50% for Staphylococcus aureus). For each bacterium, 66 specimens were subjected to biofilm formation on their surfaces for 24 hours, 66 specimens were subjected to biofilm formation on their surfaces for 48 hours, and 66 specimens were subjected to biofilm formation on their surfaces for 72 hours. Then, they were divided into groups according to disinfection method (n = 6): sterile distilled water for 10, 15, 30 min, and 6 hours (control); soap for 30 min (NES30); Opti-Free for 30 min (OPF30) and 6 h (OPF6); Efferdent for 15 min (EFF15); and 0.5%, 2%, and 4% chlorhexidine for 10 min (0.5% CHX10, 2% CHX10, and 4% CHX10). After the treatments, the specimens were vortexed to release the biofilm and the counting of bacterial colonies was performed (CFU/mL). Three-way ANOVA and the Tukey-Kramer HSD test were used (α = 0.05). For Staphylococcus epidermidis, there was no significant difference between NES30, OPF30, and OPF6 with their respective control groups; nor between NES30, OPF30, and OPF6 themselves, regardless of the biofilm development period (P >0.05). For Staphylococcus aureus, there was no significant difference between NES30 and OPF30 with their control group; nor between NES30 and OPF30 themselves, regardless of the biofilm development period (P >0.05). For Staphylococcus aureus, OPF6 showed a significant reduction in the number of CFU/mL when compared with its control group, NES30, and OPF30, regardless of the biofilm development period (P <0.05). For both bacteria, 0.5% CHX10, 2% CHX10,4% CHX10, and EFF15 showed a significant reduction in the number of CFU/mL when compared with their control groups, NES30, OPF30, and OPF6, regardless of the biofilm development period (P <0.05). Therefore, EFF15 and CHX (0.5%, 2% and 4%) were effective in reducing Staphylococcus epidermidis and Staphylococcus aureus on acrylic surfaces. NES30 and OPF (30 and 6) are not recommended.

6.
J Esthet Restor Dent ; 2020 Oct 12.
Artículo en Inglés | MEDLINE | ID: mdl-33045124

RESUMEN

OBJECTIVE: To evaluate the optical, chemical, and mechanical properties of feldspathic porcelain after handling with different instrument materials. MATERIAL AND METHODS: Feldspathic porcelain was manipulated with different spatula compositions: metal spatula (MS), plastic spatula (PS), and glass spatula (GS) for the fabrication of 30 (n = 10) disks. Contrast ratio (CR), translucency parameter (TP), and surface Knoop microhardness (KHN) were measured. The color change (ΔE00 ) was evaluated using the CIEDE2000 system. Scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) were used for surface analysis. Data were analyzed using one-way ANOVA and Tukey test (P < 0.05). RESULTS: All groups presented different morphological surfaces with higher presence of Al on the MS. PS group presented lower Al, Si, K than MS, and GS. Higher CR was observed for PS (0.734; P < 0.043), followed by MS (0.696; P < 0.043) and GS (0.65; P < 0.011). The highest TP (13.06) and KHN (386.27) were presented by GS (P < 0.001). MS and PS presented similar KHN results. The higher ΔE00 were found for plastic/metal comparison. Also, the L* values for the MS group (67.49) were lower than the other groups. CONCLUSION: The use of metal spatula promoted higher color alteration during feldspathic porcelain manipulation than did the other materials. Handling with glass instrument promoted higher microhardness than other spatula materials. CLINICAL SIGNIFICANCE: The effect of the material used for ceramic handling on feldspathic porcelain properties is often ignored. This study shows that the handling spatula material must be carefully chosen to avoid inadvertent changes to the feldspathic porcelain restoration.

7.
Eur J Dent ; 2020 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-33003238

RESUMEN

OBJECTIVE: The aim of this study is to verify the influence of three pigment incorporation methods (conventional, mechanical, and industrial) on the sorption and solubility of the MDX4-4210 and A-2186 silicones. MATERIALS AND METHODS: The groups formed were based on the silicones used (A-2186 and MDX4-4210), intrinsic pigments (pink, bronze, and black), and pigment incorporation methods (conventional, mechanical, and industrial). The dimensions of all samples were 45-mm diameter (ø) × 1-mm thickness. Readings were taken initially and after 1,008 hours of aging. STATISTICAL ANALYSIS: Three-way analysis of variance and the Tukey's test were performed (α = 0.05). RESULTS: For sorption and solubility, there was no difference between the incorporation methods for the A-2186 silicone, regardless of the pigment used (p > 0.05). For pink MDX4-4210, the industrial and mechanical methods showed higher values of sorption compared with the conventional method (p < 0.05). For bronze MDX4-4210, the industrial method showed a higher sorption value compared with the conventional and mechanical methods (p < 0.05). For black MDX4-4210, there was no difference between incorporation methods based on sorption (p > 0.05). For pink MDX4-4210, the mechanical method showed a higher solubility value compared with the industrial and conventional methods (p < 0.05). For black MDX4-4210 and bronze MDX4-4210, there was no statistically significant difference between incorporation methods based on solubility (p > 0.05). CONCLUSION: Based on sorption and solubility, for the A-2186 silicone, the conventional, mechanical, and industrial methods of pigment incorporation were equivalent. For the MDX4-4210 silicone, its results of sorption and solubility were varied, and further studies are recommended.

8.
Eur J Dent ; 2020 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-32932534

RESUMEN

SARS-CoV-2 (or 2019-nCoV) is the novel Coronavirus that affects humans. It originated in China at the end of 2019 due to the consumption of animals contaminated with this pathogen. SARS-CoV-2 causes the disease known as COVID-19 (coronavirus disease - 2019), and until May 21, 2020, approximately 213 countries and territories had been affected by SARS-CoV-2. The objective of this study was to review the origin and characteristics of this virus (SARS-CoV-2), symptoms and diagnosis of COVID-19, treatment of people with COVID-19, forms of transmission of the SARS-CoV-2, and precautions in dentistry. A literature search on PubMed/Medline was performed on the May 21, 2020, using the keywords (Mesh terms) "COVID-19" or "SARS-CoV-2" or "Coronavirus" associated with "dentistry" or "dental care" or "oral medicine." SARS-CoV-2 articles about the origin and characteristics of this virus (SARS-CoV-2), symptoms and diagnosis of COVID-19, treatment of people with COVID-19, forms of transmission of the SARS-CoV-2, and precautions in dentistry were included. The search was expanded according to necessity. Articles related to precautions in dentistry and SARS-CoV-1 or MERS-CoV were also selected, since precautions used in the dental clinic to avoid these viruses also apply to SARS-CoV-2. In addition, the references cited in the publications of articles included were also considered when appropriate. There was no limit in relation to the year of publication, and only articles written in English were included. In this study, suggestions for the safety of dental professionals were also included. Forty-seven articles and nine websites were included in this review.

9.
Int J Dent ; 2020: 8492091, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32884572

RESUMEN

Objective: To evaluate the influence of different pigmentations and accelerated aging on the hardness and tear strength of the A-2186 and MDX4-4210 silicones. Materials and Methods: The samples A-2186 and MDX4-4210 were manufactured without and with pigmentations (black, bronze, and pink). For the Shore A hardness test, 80 samples of each silicone were fabricated, and for the tear strength test, 320 samples of each silicone were fabricated. Eight groups were created for each test (n = 10). These tests were performed before and after 252, 504, and 1008 hours of aging. Three-way repeated-measures analysis of variance and the Tukey test were performed (α = 0.05). Results: The A-2186 silicone showed higher hardness and tear strength when compared with the MDX4-4210 silicone (p < 0.05), except in the hardness of the A-2186 and MDX4-4210 groups without pigmentation after 1008 hours (p > 0.05). All hardness values were between 25 and 35 units, regardless of the silicone type, period, and pigmentation (or no pigmentation). In most situations, the hardness of silicones used increased after 252 hours (p < 0.05). The nonpigmented MDX4-4210 group and all A-2186 groups showed an increase in tear strength after 252 hours (p < 0.05). For the nonpigmented MDX4-4210 group, from 252 to 1008 hours, there was no change in tear strength (p > 0.05). All pigmented MDX4-4210 groups showed no change in tear strength from 0 (initial) to 1008 hours of aging (p > 0.05). In all A-2186 groups, from 252 to 504 hours, there was a reduction in tear strength (p < 0.05), and from 504 to 1008 hours, there was an increase in tear strength (p < 0.05), except in the bronze A-2186 group (p > 0.05). Conclusion: In most situations, the A-2186 silicone showed significantly higher values of hardness and tear strength than the MDX4-4210 silicone. All hardness values were considered clinically acceptable. Accelerated aging could increase, decrease, or not significantly change the hardness and tear strength of the silicones used. The results of hardness and tear strength suggest that MDX4-4210 was more influenced by the presence of pigmentation after aging.

10.
Arch Oral Biol ; 117: 104822, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32592931

RESUMEN

OBJECTIVE: Overcoming substantial shortcomings of soft liners as physico-chemical changes and liner-biofilm-related infections remains a challenge in the rehabilitation treatment. In this study, protective non-thermal plasma (NTP) treatments were developed on the soft liner surface to improve its surface and physico-chemical properties and to reduce fungal colonization after biofilm inhibition challenge. METHODS: Resinous liner specimens (Coe-Soft) were prepared and distributed in 3 groups according to the surface treatments: (1) untreated (control); (2) treated with sulfur hexafluoride-based NTP (SF6); and (3) treated with hexamethyldisiloxane-based NTP (HMDSO). To test the NTP stability and their protective and antimicrobial effect on the liner surface over time, the morphology, chemical composition, roughness, water contact angle, shore A hardness, sorption and solubility were evaluated before and after the specimens were exposed to dual-species biofilm of Candida albicans and Streptococcus oralis for 14 days. Colony forming units and biofilm structure were assessed. Data were submitted to ANOVA and Tukey tests (α = 0.05). RESULTS: Both treatments modified the surface morphology, increased hydrophobicity and roughness of the liner, and were effective to reduce C. albicans adhesion without affecting the commensal health-associated S. oralis. HMDSO presented chemical stability and lower hardness in both periods, whereas SF6 exhibited higher initial hardness than control and the highest sorption; contrarily, similar solubility was noted for all groups. CONCLUSION: HMDSO-based film showed improved physico-chemical properties and inhibited C. albicans biofilm. Thus, it has potential for use to control candida-related stomatitis and improve liner's stability even after being exposed to biofilm inhibition challenge.


Asunto(s)
Antiinfecciosos , Biopelículas , Alineadores Dentales , Gases em Plasma , Antiinfecciosos/farmacología , Candida albicans , Ensayo de Materiales , Gases em Plasma/farmacología , Streptococcus oralis , Propiedades de Superficie
11.
Asian Pac J Cancer Prev ; 21(5): 1227-1234, 2020 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-32458626

RESUMEN

OBJECTIVE: This study aimed to evaluate the quality of life of patients with oral or oropharyngeal cancer by using specific questionnaires (QLQ-C30 and QLQ-HandN35), varying according to the location of the tumor (oral cavity or oropharynx) and the treatment performed (only surgery or surgery associated with radiotherapy). METHODS: Fifty patients were enrolled in this study and answered the EORTC QLQ-C30 and EORTC HandN35 questionnaires, before (baseline), at 1 week, and 3 months after treatment. Internal consistency reliability was calculated with the Cronbach coefficient. The Kruskal-Wallis and Wilcoxon tests were applied and P.

12.
J Clin Exp Dent ; 12(2): e103-e107, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-32071690

RESUMEN

Background: Different ceramic surface cleaning methods have been suggested after the acid conditioning. The aim was to evaluate the effect of different protocols used to remove the remaining hydrofluoric acid on the shear bond strength (SBS) between lithium disilicate and resin cement. Material and Methods: Forty-four specimens of lithium disilicate (IPS e.max Press) were divided in 4 groups (n=11): group C (control, no treatment); group HF+S (5% hydrofluoric acid + silane); group HF+US+S (5% hydrofluoric acid + ultrasound cleaning + silane); group HF+PH+S (5% hydrofluoric acid + 37% phosphoric acid + silane). Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were performed to characterize the surface morphology. The SBS test was performed on the resin/ceramic interface, and the failure mode was characterized. SBS values were submitted to 1-way ANOVA and the Tukey test (α=.05). The relation between surface treatment and failure modes was analyzed using the chi-squared test (α=.05). Results: The surface treatment type interfered in the shear strength (p<.001) and higher SBS values were observed for the groups HF+US+S (17.87 MPa) and HF+PH+S (16.37 MPa). The surface treatment did not influence the failure mode (p=.713). No fluorsilicate salts were observed after ultrasound cleaning. Conclusions: The utilization of ultrasound cleaning was an effective procedure to remove remaining fluorsilicate salts, promoting the highest SBS values. Key words:Bond strength, ceramics, fluorsilicate, lithium disilicate, resin cement.

13.
J Prosthet Dent ; 123(2): 239-245, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31227236

RESUMEN

STATEMENT OF PROBLEM: The survival and/or success of post-retained restorations is influenced by the amount of residual coronal structure, known as the "ferrule effect." PURPOSE: The purpose of this systematic review and meta-analysis was to evaluate whether the presence or absence of the ferrule effect influences the failure rate of fiber-reinforced composite post-and-core restorations. MATERIAL AND METHODS: A comprehensive review of the literature was performed using the PubMed/Medline, Embase, Scopus, and Cochrane Library databases for articles published up to May 2018. The risk ratio with 95% confidence interval was estimated using the Mantel-Haenszel method. Potentially eligible studies were selected based on the reading of the abstracts and full text of prospective clinical trials, randomized clinical trials, or prospective randomized studies, all with a minimum of 10 participants in each group, with a follow-up period longer than 6 months, and published in English. RESULTS: Of the 380 studies retrieved, 4 were included in this meta-analysis. A total of 297 teeth were evaluated, 157 with a ferrule and 140 without a ferrule. The mean survival rate was 88.35% in the ferrule group and 78.05% in the nonferrule group. No statistically significant difference was noted in the general failure analysis (risk ratio: 0.71 [95% confidence interval: 0.47 to 1.06]; P=.09), although a higher number of failures occurred in nonferrule restorations. More controlled and randomized clinical trials are needed to establish a clinical protocol for the use of post-retained restorations. CONCLUSIONS: Despite the limited number of available studies, the results of this meta-analysis suggest that the ferrule effect does not significantly reduce the failure rate in fiber-reinforced composite post-and-core restorations.


Asunto(s)
Resinas Compuestas , Técnica de Perno Muñón , Diente no Vital , Fracaso de la Restauración Dental , Humanos , Estudios Prospectivos
14.
Eur J Dent ; 13(3): 399-404, 2019 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-31795004

RESUMEN

OBJECTIVE: To analyze the influence of three pigment incorporation methods on color change, dimensional stability, and detail reproduction of the MDX4-4210 and A-2186 silicones. MATERIALS AND METHODS: The A-2186 and MDX4-4210 silicones were used for preparation of samples, with the incorporation of bronze, black and pink pigments, usingconventional, mechanical, and industrial incorporation methods. Samples were submitted to the initial readings of color (n = 10; 22-mm diameter × 2-mm thickness), detail reproduction, and dimensional stability (n = 10; 30-mm diameter × 3-mm thickness). Readings were also taken at the end of 252, 504 and 1,008 hours of aging cycles. RESULTS: Quantitative data were evaluated by ANOVA and Tukey test, with a level of significance of 5%. The mechanical and industrial methods caused smaller color changes of all samples compared with the conventional method (p < 0.05). In most cases, the mechanical and industrial methods caused less samples' contraction than the conventional method after aging (p < 0.05). The color change values increased progressively in each aging period for all samples (p < 0.05). The contraction values increased progressively in each aging period for all samples (p < 0.05). In the qualitative analysis of detail reproduction, all samples presented full reproduction of the three grooves, with accurate angles, initially and after the aging periods. CONCLUSIONS: The industrial and mechanical methods showed the best results for color and dimensional stability. Despite the statistical differences, all pigment incorporation methods generated acceptable dimensional and color changes of the MDX4-4210 and A-2186 silicones, regardless of the pigment and aging. In addition, the detail reproduction was satisfactory after aging periods in all cases of this study, showing the excellent quality of the A-2186 and MDX4-4210 silicones.

15.
J Clin Exp Dent ; 11(9): e807-e813, 2019 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-31636873

RESUMEN

Background: The aim of this study was to evaluate the distribution of stress in complete fixed mandibular prostheses with infrastructures (IE) fabricated with different materials and techniques, under compressive force. Material and Methods: A model of an edentulous mandible, which received five 4x11 mm external hexagon implants between the mental foramens, was fabricated. The groups were divided into: Group I - IE in nickel-chromium with an acrylic resin occlusal coating; Group II - IE in nickel-chromium with a ceramic occlusal coating; Group III - IE milled in zirconia with a ceramic coating. For the photoelastic methodology, 70 N axial loads were applied in three regions. Photographic images were taken and analyzed according to the number of high-intensity fringes. For the strain gauge methodology, the measurement of stresses was performed in two distinct regions. The same compression tests described earlier were then performed. The registered stress values were grouped in tables and submitted to two-factor variance analysis (ANOVA) and the Tukey test with 5% significance. Results: The results of the two methodologies demonstrated smaller stress values for Group I, when compared to the other groups. Conclusions: It was possible to conclude that the complete fixed prostheses, with infrastructures cast in metal and acrylic occlusal coating, demonstrated better biomechanical results. Key words:Dental implants, mandibular prosthesis implantation, biomechanics.

16.
Artículo en Inglés | MEDLINE | ID: mdl-31592306

RESUMEN

Background. Implant fractures can cause difficult problems for patients and dentists. This systematic review aimed to determine the influence of some implant parameters on the occurrence of their fracture and to determine the incidence of fractures reported in recent years. Methods. A search was conducted in Pubmed database, from which 12 studies published in the last 12 years were selected. Results. This review reported a 2% incidence of implant fracture. Most implants had been in function between 3 and 4 years until fracture. The studies did not provide necessary information to establish a relationship between the different parameters of implants and the incidence of fractures. Conclusion. Thus, the indication of type, diameter and length of an implant and the bone quality in the region receiving it should be studied and accurately examined for each individual case in order to avoid future failures.

17.
J Investig Clin Dent ; 10(4): e12452, 2019 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-31478358

RESUMEN

AIM: This study aimed to investigate the adhesion of Streptococcus sanguinis to the surface of interim prostheses that were treated or not treated with a light-activated glaze, and subjected or not subjected to a thermocycling procedure. METHODS: 36 specimens of each resin were divided into 4 groups: heat-activated acrylic resin; chemically-activated acrylic resin; bis-acryl composite resin (Protemp; 3M ESPE); and bis-GMA (Charisma; Heraeus Kulzer). Half of the specimens underwent application of glaze and the other half underwent mechanical polishing. Specimens were randomly distributed into groups (N = 9) with and without thermocycling (2000 cycles). Surface energy, roughness and microbiological analyses were performed. RESULTS: Groups treated with glaze showed lower roughness when compared with the same groups without glaze treatment, before and after thermocycling, except for the bis-acryl groups after thermocycling. Surface energy values were higher in the groups treated with glaze, except the bis-acryl group before and after thermocycling. After thermocycling, the values of bacterial adhesion decreased numerically, with the exception of the chemically-activated acrylic resin group treated with glaze and the heat-activated acrylic resin group without glaze treatment. CONCLUSION: The application of glaze and the thermocycling do not influence, in a statistically significant manner, the bacterial adhesion on polymer surfaces.


Asunto(s)
Resinas Compuestas , Polímeros , Bisfenol A Glicidil Metacrilato , Ensayo de Materiales , Prótesis e Implantes , Streptococcus , Propiedades de Superficie
18.
Int J Dent ; 2019: 8657619, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31396279

RESUMEN

This review presents a classification system for maxillofacial prostheses, while explaining its types. It also aims to describe their origin and development, currently available materials, and techniques, predicts the future requirements, and subsequently discusses its avenues for improvement as a restorative modality. A literature search of the PubMed/Medline database was performed. Articles that discussed the history, types, materials, fabrication techniques, clinical implications, and future expectations related to maxillofacial prostheses and reconstruction were included. Fifty-nine articles were included in this review. Maxillofacial prostheses were classified as restorative or complementary with subclassifications based on the prostheses finality. The origin of maxillofacial prostheses is unclear; however, fabrication techniques and materials have undergone several changes throughout history. Currently, silicones and acrylic resins are the most commonly used materials to fabricate customized prostheses. Maxillofacial prostheses not only restore several types of orofacial defects but also improve the patients' quality of life. Although the current clinical scenario concerning the field of maxillofacial prostheses is promising, improvements in material quality and techniques for maxillofacial prostheses may be expected in the future, to produce better results in the treatment of patients.

19.
J Prosthodont ; 28(6): 692-700, 2019 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-31125155

RESUMEN

PURPOSE: To investigate the influence of nonthermal plasma (NTP) treatment on the tensile bond strength between heat-polymerized acrylic resin for ocular prostheses and silicone reliner, with and without the use of an adhesive primer. MATERIALS AND METHODS: One-hundred and sixty-four acrylic resin specimens were fabricated and randomly distributed into four groups according to the type of surface treatment: Sofreliner Primer, NTP, Sofreliner Primer + NTP, and NTP + Sofreliner Primer. Two specimens interposed with relining material (Sofreliner) formed one test sample to perform the tensile bond strength tests, before (initial) and after storage (final) in saline solution (37°C, 90 days, n = 10). Surface characterization was performed by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The failure type was classified as cohesive, adhesive, or mixed. The data were analyzed statistically using the two-way ANOVA and Tukey test, as well as the chi-squared test (α = 0.05), Bonferroni correction (α = 0.005), and Spearman correlation coefficient (α = 0.05). RESULTS: The SEM and EDS analyses showed the presence of a thin, homogenous organic film in the groups treated with NTP. The NTP + Sofreliner Primer group presented the largest bond strength mean values in the initial period (p < 0.05). Sofreliner Primer and NTP + Sofreliner Primer groups presented the first and second largest tensile bond strength mean values in the final period (p < 0.05), respectively. NTP + Sofreliner Primer group also had the largest number of cohesive (70%, initial) and mixed (90%, final) failures. CONCLUSIONS: The NTP treatment performed before the primer application enhanced the bond between the acrylic resin ocular prosthesis and the Sofreliner silicone-based reliner, even after 90 days of immersion in saline solution.


Asunto(s)
Recubrimiento Dental Adhesivo , Siliconas , Resinas Acrílicas , Cementos Dentales , Análisis del Estrés Dental , Ojo Artificial , Ensayo de Materiales , Propiedades de Superficie , Resistencia a la Tracción
20.
BMC Oral Health ; 19(1): 75, 2019 05 03.
Artículo en Inglés | MEDLINE | ID: mdl-31053131

RESUMEN

BACKGROUND: The aim was to analyze the levels of stress of edentulous patients through the state-trait anxiety inventory (STAI) and salivary flow through the visual analogue scale (VAS) xerostomia questionnaire, as well as analyze the levels of cortisol, capillary blood glucose, and blood pressure (BP) before and after the installation of complete dentures. METHODS: Fifty patients were evaluated. The STAI and VAS xerostomia questionnaire were applied before the installation of the prosthesis, on the day of its installation, and 1 month after the last recall visit. The BP measurement, as well as salivary and blood collections, were performed before the installation of the prothesis, and 1 month after the last recall visit. Data from the VAS xerostomia questionnaire and cortisol levels were submitted to ANOVA and the Tukey test (P = .05). Data from the STAI, as well as blood glucose and BP levels, were submitted to the Chi-square test (P = .05). The correlation between cortisol and blood glucose and between cortisol levels and BP was analyzed. RESULTS: There was no statistically significant association between the questions of the VAS xerostomia questionnaire, STAI-state and STAI-trait scores, or the periods analyzed. However, the cortisol level collected in the morning decreased after the installation of the prosthesis. There was a correlation between cortisol and blood glucose and BP levels. CONCLUSIONS: The installation of complete dentures was beneficial for patients since it was probably responsible for the cortisol level reduction.


Asunto(s)
Ansiedad/metabolismo , Glucemia/metabolismo , Presión Sanguínea/fisiología , Dentadura Completa/psicología , Hidrocortisona/metabolismo , Estrés Psicológico/diagnóstico , Estrés Psicológico/psicología , Ansiedad/psicología , Humanos
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