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1.
PLoS One ; 15(8): e0237195, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32764819

RESUMEN

This study investigated the caries-preventive effect of 445 nm laser radiation in combination with fluoride on the prevention of white spot lesions. Previously, several studies have indicated the ability of 488 nm argon ion laser irradiation to reduce early enamel demineralization. A diode laser (445 nm) could be an alternative technology for possible caries-preventive potential. Each sample of a group of seventeen caries-free bovine teeth was treated in four different ways on four different zones of the labial surface: control/no treatment (C), laser irradiation only (L) (0.3 W, 60 s and applied dose of 90 J/cm2), amine fluoride application only (10,000 ppm and pH 3.9) (F), and amine fluoride application followed by laser irradiation (FL). After treatment, the teeth were subjected to a demineralization solution (pH 4.3 for 48 h at 37 °C) to induce subsurface lesions. After sectioning, the teeth were examined by light microscopy. Three teeth were analyzed by scanning electron microscopy (SEM). The depths of the subsurface lesions in the C, L, F, and FL groups were 103.01 (± 13.04), 96.99 (± 14.51), 42.59 (± 17.13), and 24.35 (± 11.38) µm, respectively. The pairwise group comparison showed the following results: p < 0.001 for FL versus C, FL versus L, F versus C, and F versus L, p = 0.019 for FL versus F and p = 0.930 for L versus C. The SEM micrographs support the light-microscopic examination. The results of the current study have shown that using relatively low irradiation settings of 445 nm laser on fluoridated enamel may be effective for prevention of white spot lesions.


Asunto(s)
Caries Dental/prevención & control , Fluoruros Tópicos/administración & dosificación , Terapia por Luz de Baja Intensidad/métodos , Desmineralización Dental/prevención & control , Animales , Bovinos , Terapia Combinada/métodos , Esmalte Dental/efectos de los fármacos , Esmalte Dental/efectos de la radiación , Esmalte Dental/ultraestructura , Humanos , Láseres de Semiconductores/uso terapéutico , Microscopía Electrónica de Rastreo
2.
J Cancer Res Ther ; 16(3): 612-618, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32719276

RESUMEN

Objective: The objective of this study is to evaluate the effects of radiotherapy doses on mineral density and percentage mineral volume of human permanent tooth enamel. Materials and Methods: Synchrotron radiation Xray microcomputed tomography (SRµCT) and microhardness testing were carried out on 8 and 20 tooth samples, respectively. Enamel mineral density was derived from SRµCT technique using ImageJ software. Microhardness samples were subjected to Vickers indentations followed by calculation of microhardness and percentage mineral volume values using respective mathematical measures. Data were analyzed using paired t-test at a significance level of 5%. Qualitative analysis of the enamel microstructure was done with two-dimensional projection images and scanned electron micrographs using µCT and field emission scanning electron microscopy, respectively. Results: Vickers microhardness and SRµCT techniques showed a decrease in microhardness and an increase in mineral density, respectively, in postirradiated samples. These changes were related to mineral density variation and alteration of hydroxyapatite crystal lattice in enamel surface. Enamel microstructure showed key features such as microporosities and loss of smooth homogeneous surface. These indicate tribological loss and delamination of enamel which might lead to radiation caries. Conclusions: Tooth surface loss might be a major contributing factor for radiation caries in head-and-neck cancer patients prescribed to radiotherapy. Such direct effects of radiotherapy cause enamel abrasion, delamination, and damage to the dentinoenamel junction. Suitable measures should, therefore, be worked out to protect nontarget oral tissues such as teeth while delivering effective dosages to target regions.


Asunto(s)
Esmalte Dental/efectos de la radiación , Neoplasias de Cabeza y Cuello/radioterapia , Traumatismos por Radiación/etiología , Desmineralización Dental/etiología , Esmalte Dental/ultraestructura , Dureza/efectos de la radiación , Neoplasias de Cabeza y Cuello/patología , Humanos , Técnicas In Vitro , Microscopía Electrónica de Rastreo/métodos , Traumatismos por Radiación/patología , Propiedades de Superficie , Desmineralización Dental/patología , Microtomografía por Rayos X/métodos
3.
Lasers Med Sci ; 35(7): 1629-1636, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32382936

RESUMEN

The aim of this study is to evaluate the ability of quantitative light-induced fluorescence (QLF) to monitor enamel caries lesions of different severity stages located on the occlusal surfaces of permanent teeth before and after treatment with resin infiltrant. Sixty extracted permanent teeth had one occlusal site selected and were categorized according to the International Caries Detection and Assessment System (ICDAS) criteria. The teeth were divided into three groups (n = 20): ICDAS 1, ICDAS 2, and ICDAS 3. The teeth were assessed by a trained examiner using QLF in two phases: (A) before and (B) after treatment with resin infiltrant. The caries lesions were evaluated using the following QLF parameters: area (mm2); ΔF, fluorescence loss (%); and ΔQ, fluorescence loss integrated over the lesion area (%*mm2). The resin infiltrant (Icon™) was applied on the occlusal surface following the manufacturer's recommendations. The teeth were then sectioned and prepared for polarized light microscopy analysis. The penetration of resin infiltrant was measured with ImageJ. The groups showed a statistically significant difference in all QLF parameters before and after caries infiltration, with the reduction of fluorescence values posttreatment (p < 0.05). Infiltrant penetration was observed in all groups, with a statistical difference between all groups (p < 0.05). The reduction in QLF parameters after resin infiltration suggests that QLF is able to monitor enamel caries lesions of different severity stages located on the occlusal surfaces of permanent teeth before and after treatment with resin infiltrant.


Asunto(s)
Caries Dental/diagnóstico , Esmalte Dental/efectos de la radiación , Fluorescencia Cuantitativa Inducida por la Luz , Resinas Sintéticas/farmacología , Caries Dental/patología , Esmalte Dental/efectos de los fármacos , Humanos , Diente/patología
4.
J Appl Oral Sci ; 28: e20190720, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32428059

RESUMEN

Objective This study evaluated the clinical effect of violet LED light on in-office bleaching used alone or combined with 37% carbamide peroxide (CP) or 35% hydrogen peroxide (HP). Methodology A total of 100 patients were divided into five groups (n=20): LED, LED/CP, CP, LED/HP and HP. Colorimetric evaluation was performed using a spectrophotometer (ΔE, ΔL, Δa, Δb) and a visual shade guide (ΔSGU). Calcium (Ca)/phosphorous (P) ratio was quantified in the enamel microbiopsies. Measurements were performed at baseline (T 0 ), after bleaching (T B ) and in the 14-day follow-up (T 14 ). At each bleaching session, a visual scale determined the absolute risk (AR) and intensity of tooth sensitivity (TS). Data were evaluated by one-way (ΔE, Δa, ΔL, Δb), two-way repeated measures ANOVA (Ca/P ratio), and Tukey post-hoc tests. ΔSGU and TS were evaluated by Kruskal-Wallis and Mann-Whitney, and AR by Chi-Squared tests (a=5%). Results LED produced the lowest ΔE (p<0.05), but LED/HP promoted greater ΔE, ΔSGU and Δb (T 14 ) than HP (p<0.05). No differences were observed in ΔE and ΔSGU for LED/CP and HP groups (p>0.05). ΔL and Δa were not influenced by LED activation. After bleaching, LED/CP exhibited greater Δb than CP (p>0.05), but no differences were found between these groups at T 14 (p>0.05). LED treatment promoted the lowest risk of TS (16%), while HP promoted the highest (94.4%) (p<0.05). No statistical differences of risk of TS were found for CP (44%), LED/CP (61%) and LED/HP (88%) groups (p>0.05). No differences were found in enamel Ca/P ratio among treatments, regardless of evaluation times. Conclusions Violet LED alone produced the lowest bleaching effect, but enhanced HP bleaching results. Patients treated with LED/CP reached the same efficacy of HP, with reduced risk and intensity of tooth sensitivity and none of the bleaching protocols adversely affected enamel mineral content.


Asunto(s)
Peróxido de Carbamida/administración & dosificación , Peróxido de Hidrógeno/administración & dosificación , Luz , Fototerapia/métodos , Blanqueadores Dentales/administración & dosificación , Blanqueamiento de Dientes/métodos , Adolescente , Adulto , Análisis de Varianza , Colorimetría , Terapia Combinada , Esmalte Dental/efectos de los fármacos , Esmalte Dental/efectos de la radiación , Sensibilidad de la Dentina/inducido químicamente , Femenino , Humanos , Masculino , Valores de Referencia , Factores de Riesgo , Espectrofotometría , Estadísticas no Paramétricas , Propiedades de Superficie/efectos de los fármacos , Propiedades de Superficie/efectos de la radiación , Resultado del Tratamiento , Adulto Joven
5.
Lasers Med Sci ; 35(7): 1607-1620, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32472426

RESUMEN

The aim of the present study was to evaluate the effects of different remineralization agents associated with erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) (0.5 W power, 20 Hz frequency, 60% water, 40% air, 25 mJ pulse energy, 8.84 J/cm2 fluence, 60 µs pulse duration, 600 µm tip diameter, and an approximate 1-1.5 mm distance to the target) laser irradiation on erosion induced by the consumption of carbonated drinks in human primary enamel. There were 8 groups and 10 primary teeth in each g0roup. The distribution was as follows: group 1, casein phosphopeptide-amorphous calcium phosphate with fluoride (CPP-ACPF); group 2, Er,Cr:YSGG laser+CPP-ACPF; group 3, fluor varnish; group 4, Er,Cr:YSGG Laser+fluoride varnish; group 5, ROCS® medical mineral gel; group 6, Er,Cr:YSGG laser + ROCS® medical mineral gel; group 7, Er,Cr:YSGG laser; and group 8, artificial saliva. The samples in the groups were submerged in artificial saliva and acid twice a day for 6 s at 6-h intervals and were then exposed to an erosion cycle 15 times. In the groups in which the Er,Cr:YSGG laser was applied in combination with the remineralization agents, the laser application was made first, and then the remineralization agents were applied for 4 min in each group. The Friedman and Wilcoxon signed-rank tests and the Bonferroni correction were used in statistical analyses, and the significance level was taken as p < 0.05. According to the results, all agents had a statistically significant difference (groups 1, 2, 3, 4, and 6: p = 0.005, p < 0.017; groups 5 and 7: p = 0.007, p < 0.017) between BL-RM periods. However, all agents had a statistically significant remineralization effect on primary teeth enamel (groups 1, 2, 3, 6, and 7: p = 0.005, p < 0.017; group 4: p = 0.011, p < 0.017) except that group 5 (p = 0.074, p < 0.017) between DM-RM periods. The coadministration of an agent with the laser did not make any difference at a statistical level (p = 0.804, p > 0.05). The results were supported by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. As a result of this study, CPP-ACPF had a notable impact in terms of the remineralization effect on eroded enamel, and the Er,Cr:YSGG laser alone may be an alternative method, which may be related to the modified hydroxyapatite structure, 38.5% H0.56Ca4.56O13P3Y0.44, that was determined in XRD analysis.


Asunto(s)
Esmalte Dental/efectos de la radiación , Láseres de Estado Sólido/uso terapéutico , Erosión de los Dientes/cirugía , Remineralización Dental , Diente Primario/efectos de la radiación , Esmalte Dental/ultraestructura , Dureza , Humanos , Difracción de Rayos X
6.
Lasers Med Sci ; 35(7): 1621-1628, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32333336

RESUMEN

The aim of this study was to compare the clinical performance of clinical-visual examination using the International Caries Detection and Assessment System (ICDAS) II, digital bitewing radiography, near-infrared light transillumination (NIR-LT), and laser fluorescence (LF) for the detection of non-cavitated proximal enamel and dentin caries. The study included 335 patients, aged 12-18 years, with no cavities in the posterior teeth. Clinical-visual inspections of 335 non-cavitated proximal caries were performed by two examiners. For enamel caries, clinical validation included a combination of clinical-visual and digital bitewing radiography assessments. For dentin caries, the clinical validation was opening the cavity. The accuracy rate, sensitivity, specificity, predictive values, and areas under receiver operating characteristic curves were determined. The agreement between the examiners' measurements was calculated using the kappa coefficient. The sensitivity, specificity, and accuracy of the methods were compared using the McNemar test. The significance level was set at p < 0.05. Digital bitewing radiography had the highest sensitivity (0.96) and accuracy (0.96), and LF had the lowest sensitivity (0.38) and accuracy (0.39). After separation of the lesions into enamel and dentin caries, clinical-visual examination had the highest sensitivity (0.98) and accuracy (0.98) for enamel caries, while digital bitewing radiography had the highest sensitivity (0.97) and accuracy (0.97) for dentin caries. The NIR-LT method had a higher sensitivity for enamel caries (0.86). Each method also differed significantly from the others (p < 0.001). Digital bitewing radiography gave the best prediction of proximal enamel and dentin caries. NIR-LT showed good potential for detection of proximal caries.


Asunto(s)
Caries Dental/diagnóstico por imagen , Caries Dental/diagnóstico , Esmalte Dental/efectos de la radiación , Dentina/efectos de la radiación , Rayos Infrarrojos , Rayos Láser , Radiografía de Mordida Lateral , Transiluminación , Caries Dental/patología , Esmalte Dental/diagnóstico por imagen , Dentina/diagnóstico por imagen , Dentina/patología , Fluorescencia , Humanos , Valor Predictivo de las Pruebas , Curva ROC , Reproducibilidad de los Resultados , Adulto Joven
7.
Int J Radiat Biol ; 96(7): 910-918, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-32159405

RESUMEN

Purpose: The main goal of this study was to evaluate the impact of different ionizing radiation doses on the mineral (carbonate/phosphate ratio, crystallinity index [CI]) and organic (amide III/phosphate, amide I sub-band ratios) structures, as well as the microhardness, of enamel and dentin, along with their influence on the bonding strength stability of the etch-and-rinse (ER) and self-etch (SE) dental adhesive strategies.Materials and methods: Enamel and dentin human tissue specimens were irradiated (with 0, 20, 40, and 70 Gy radiation doses, respectively) and sectioned to perform an attenuated total reflection-Fourier transform IR spectroscopy assay (ATR-FTIR) and the Vickers microhardness (VHN) test to conduct a biochemical and biomechanical evaluation of the tissues. Regarding the adhesive properties, restored enamel and dentin specimens exposed to the same radiation doses were submitted to microshear bond strength (µSBS) tests for enamel in immediate time (IM) and to microtensile bond strength (µTBS) tests after for IM and 12-month (12 M) period of time, Mann-Whitney U tests were implemented, using the ATR-FTIR data for significant differences (α < 0.05), and three- and two-way analyses of variance, along with post-testing, were performed on the µTBS and µSBS data (MPa), respectively (Tukey post hoc test at α = 0.05).Results: The ATR-FTIR results showed a significant decrease (p < .05) in the amide III/phosphate ratio after 20 Gy for the enamel and after 40 Gy for the dentin. The CI was significantly reduced for both tissues after a dose of 70 Gy (p < .05). All radiation doses significantly decreased microhardness values, relative to the respective enamel and dentin controls (p < .05). In both tissues and adhesive strategies, the decrease in bond strength was influenced by ionizing radiation starting from 40 Gy. The ER strategy showed high percentages of enamel cohesive failure. In general, ER in both tissues showed greater and more stable bond strength than SE against increased radiation doses and long term.Conclusions: It is possible to conclude that structural alterations of enamel and dentin are generated by all radiation doses, decreasing the microhardness of dental hard tissues and influencing bond strength over time, starting at 40 Gy radiation dose. The etch-and-rinse strategy demonstrates better adhesive performance but generates cohesive fractures in the enamel.


Asunto(s)
Restauración Dental Permanente , Diente Molar/efectos de la radiación , Radioterapia/efectos adversos , Diente/efectos de la radiación , Esmalte Dental/citología , Esmalte Dental/efectos de la radiación , Dentina/citología , Dentina/efectos de la radiación , Dureza/efectos de la radiación , Humanos , Diente Molar/citología
8.
Lasers Med Sci ; 35(5): 1213-1222, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-32030555

RESUMEN

The aim of this in vitro study was to evaluate the protective effect of short-pulsed CO2 9.3 µm laser irradiation against erosion in human enamel without and combined with TiF4 and AmF/NaF/SnCl2 applications, respectively, as well as compared to the protective effect of these fluoride treatments alone. After polishing, ninety enamel samples (3 × 3mm) were used for 9 different treatment groups: 4% TiF4 gel (pH 1.5, 24,533 ppm F-); AmF/NaF/SnCl2 rinse (pH 4.5; 500 ppm F-, 800 ppm Sn2); CO2 laser (average power 0.58 W); CO2 laser (0.58 W) + TiF4; CO2 laser (0.58 W) + AmF/NaF/SnCl2; CO2 laser (0.69 W); CO2 laser (0.69 W) + TiF4; CO2 laser (0.69 W) + AmF/NaF/SnCl2; negative control (deionized water). TiF4 gel was brushed on only once before the first erosive cycling, while samples treated with AmF/NaF/SnCl2 were daily immersed in 5 ml of the solution before cycling. Laser treatment occurred with a CO2 laser (wavelength 9.3 µm, pulse repetition rate 100 Hz, pulse duration 14.6 µs/18 µs, average power 0.58 W/0.69 W, fluence 1.9 J/cm2/2.2 J/cm2, beam diameter 0.63 mm, irradiation time 10 s, air cooling). TiF4 was applied only once, while AmF/NaF/SnCl2 was applied once daily before the erosive challenge. Surface loss (in µm) was measured with optical profilometry immediately after treatment, and after 5 and 10 days of erosive cycling (0.5% citric acid, pH 2.3, 6 × 2 min/day). Additionally, scanning electron microscopy investigations were performed. All application measures resulted in loss of surface height immediately after treatment. After 5 days, significantly reduced surface loss was observed after applying laser irradiation (both power settings) followed by applications of TiF4 or AmF/NaF/SnCl2 solution (p < 0.05; 2-way ANOVA and Tukey test) compared to fluoride application alone. After 10 days, compared to after 5 days, a reduced tissue loss was observed in all groups treated with AmF/NaF/SnCl2 solution. This tissue gain occurred with the AmF/NaF/SnCl2 application alone and was significantly higher when the application was combined with the laser use (p < 0.05). Short-pulsed CO2 9.3 µm laser irradiation followed by additional application of AmF/NaF/SnCl2 solution significantly reduces the progression of dental enamel erosion in vitro.


Asunto(s)
Esmalte Dental/patología , Esmalte Dental/efectos de la radiación , Fluoruros/uso terapéutico , Láseres de Gas/uso terapéutico , Erosión de los Dientes/cirugía , Esmalte Dental/ultraestructura , Humanos , Compuestos de Estaño/uso terapéutico
9.
Lasers Med Sci ; 35(5): 1193-1203, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-32006264

RESUMEN

This study investigated the combined effect of CO2 laser irradiation and Remin Pro paste on microhardness of enamel white spot lesions (WSLs). Seventy-eight intact premolars were randomly assigned into six groups and then stored in a demineralizing solution to create WSLs. Afterwards, the teeth in group 6 (negative control) remained untreated, while groups 1 and 4 were exposed to CO2 laser irradiation (20 Hz, 1 W, 30 s) and Remin Pro paste, respectively. In groups 2 and 3, the teeth were exposed to laser either before (group 2) or after (group 3) Remin Pro application. The teeth in groups 1 to 5 were then immersed in artificial saliva for 90 days while subjected to fluoride mouthwash and weekly brushing. Finally, the teeth were sectioned, and Vickers microhardness was measured at the enamel surface and at 50, 100, and 150 µm from the surface. One sample of each group was also examined with scanning electron microscope (SEM). Data were analyzed by two-way analysis of variance (ANOVA) and Tukey's test. The significance was set at 0.05. Laser irradiation followed by Remin Pro application (group 2) caused a significant increase in total WSLs' microhardness compared with laser alone (group 1) and control groups (P < 0.05). Microhardness at depths of 100 and 150 µm was also significantly greater in group 2 compared with those of group 3 and control groups (P < 0.05). Combined application of CO2 laser with Remin Pro paste, when laser is irradiated before the paste, is suggested for re-hardening of WSLs in deep layers of enamel.


Asunto(s)
Caries Dental/cirugía , Esmalte Dental/patología , Esmalte Dental/efectos de la radiación , Láseres de Gas/uso terapéutico , Pastas de Dientes/uso terapéutico , Esmalte Dental/ultraestructura , Dureza , Humanos
10.
Med. oral patol. oral cir. bucal (Internet) ; 25(1): e96-e105, ene. 2020. graf
Artículo en Inglés | IBECS | ID: ibc-196201

RESUMEN

BACKGROUND: Radiotherapy is widely used in contemporary head and neck cancer treatment protocols. The abil-ity of head and neck radiotherapy (HNRT) to cause direct radiogenic destruction to the teeth is one of the most controversial topics in the field of oral oncology. Therefore, this systematic review aimed to investigate ionising radiation as an independent factor for physical and chemical changes on the dentine-enamel junction (DEJ), a piv-otal dental topography for the onset and progression of radiation-related caries (RRC) and enamel delamination. MATERIAL AND METHODS: Systematic searches were conducted on three databases: Scopus, MEDLINE (Via PubMed) and Embase (Elsevier). Laboratory studies evaluating the effects of simulated or in vivo HNRT on the DEJ were included. The GRADE tool adapted for in vitro studies was used to assess the methodological quality. RESULTS: Of the 154 initially selected studies, eight met the inclusion criteria, from which five studies were graded as high quality of evidence, two studies were graded as moderate quality and one as low quality. Two studies did not demonstrate DEJ alterations following HNRT while the other six articles described several organic and inorganic changes in the DEJ of irradiated teeth samples. These radiogenic events were mostly detected through micro and na-noindentation, Raman micro-spectroscopy, confocal microscopy, Western blotting and optical coherence tomography. CONCLUSIONS: HNRT may have a negative impact on the physical and chemical aspects of the DEJ, predisposing can-cer patients to RRC and enamel delamination


No disponible


Asunto(s)
Humanos , Neoplasias de Cabeza y Cuello/radioterapia , Traumatismos por Radiación/complicaciones , Esmalte Dental/efectos de la radiación , Dentina/efectos de la radiación , Caries Dental/etiología , Factores de Riesgo , Progresión de la Enfermedad
11.
Lasers Med Sci ; 35(4): 853-860, 2020 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-31486933

RESUMEN

Resin cements create a high bond between the tooth and ceramic surfaces, thus making it impossible to remove the restoration in one piece. The aims of this study were to evaluate (i) the efficiency of an Er:YAG laser for debonding, and (ii) the changes in the rebonding strength values of all-ceramic veneers, which were removed after laser application. A tooth reduction of 120 extracted human maxillary central incisors was made to provide two different bonding surfaces (60 enamel and 60 dentin). Sixty leucite and 60 lithium disilicate discs (1-mm thickness, 5-mm diameter) were cemented to prepared surfaces with a dual-cure resin cement. Each group was divided into two subgroups (n = 15): control and laser-irradiated. Er:YAG laser (2940 nm) was applied for 9 s at 3 W power (10 Hz, 300 mJ) with 100 µs pulse duration. Shear bond strength (SBS) test was made with a universal testing machine. After the tested laser-irradiated specimens had been rebonded, the SBS test was performed again and rebonding strengths were measured. The statistical evaluations were performed by using repeated measures one-way ANOVA and post hoc Bonferroni tests (p < 0.05). Significant differences were found between the control and laser-irradiated groups (p < 0.001). While the required SBS values for control groups were between 30.04 and 24.66 MPa, the values for laser-irradiated groups were between 6.60 and 4.09 MPa. There was no significant difference between the control and rebonded groups. Er:YAG laser-irradiation is an effective method for removing all-ceramic restorations without affecting the rebonding strength.


Asunto(s)
Silicatos de Aluminio/efectos de la radiación , Recubrimiento Dental Adhesivo , Porcelana Dental/efectos de la radiación , Láseres de Estado Sólido , Esmalte Dental/efectos de la radiación , Dentina/efectos de la radiación , Humanos , Ensayo de Materiales , Resistencia al Corte
12.
Lasers Med Sci ; 35(1): 13-30, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31399861

RESUMEN

Since the invention of lasers in dentistry, investigations in caries prevention by the use of laser radiation have been proposed. There are several mechanisms stated for this purpose such as photothermal and/or photochemical interaction processes with the enamel. Alone or in conjugation with topical fluoride application, this treatment modality may improve enamel acid resistance in high-caries-risk populations. Data collection was done by searching the keywords caries, prevention, and laser in PubMed, Embase, Web of Science, Cochrane Library, and Google Scholar. Lasing protocols of the collected literature and their effectiveness as well as examination methods used to verify treatment outcomes have been evaluated. One hundred eighteen publications were found for the last 10 years. The wavelengths investigated for caries prevention are mainly located in the near and the mid-infrared spectral range. In the evaluated period of time, investigations using CO2; Er:YAG; Er,Cr:YSGG; Er:YLF; fundamental, second, and third harmonic generations of Nd:YAG; diodes; and argon ion lasers were found in the databases. Accounting for 39% of the literature, CO2 laser was the most examined system for this purpose. Reviewing the literature in this narrative review showed that all laser systems presented a positive effect in varying degrees. Laser irradiation could be an alternative or synergistic to topical fluoridation for enamel caries prevention with longer lasting effect. Further research should be focused on selecting proper laser settings to avoid damage to enamel and developing effective evidence-based clinical protocols.


Asunto(s)
Caries Dental/prevención & control , Caries Dental/cirugía , Esmalte Dental/patología , Esmalte Dental/efectos de la radiación , Humanos , Láseres de Gas/uso terapéutico , Riesgo , Resultado del Tratamiento
13.
Support Care Cancer ; 28(1): 239-247, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31020438

RESUMEN

OBJECTIVES: To evaluate the in vitro effects of radiotherapy (RT) on the morphological surface of the enamel and dentin and to determine the best adhesive system and most appropriate time to restore teeth in head and neck cancer patients. METHODS: Sixty third molars were cut into 120 enamel fragments and 120 dentin fragments and divided into four groups (n = 30): G1 (control): nonirradiated, only restorative procedure; G2: restorative procedure immediately before RT; G3: restorative procedure immediately after RT; and G4: restorative procedure 6 months after RT. Each group was divided into two subgroups: Adper™ Single Bond 2 (SB) and Clearfill SE Bond (CL) based on the material used. After RT and restorative procedures, the specimens were subjected to confocal microscopy and shear bond strength test. Data were analyzed using a two-way ANOVA followed by Tukey's test at a significance level of 5%. RESULTS: Morphological changes were observed in both substrates after a cumulative dose of 40 Gy, and after 60 Gy, the changes were more evident in both substrates. CL had the highest strength values in both substrates (p < 0.05), and G2 had the lowest strength values for the enamel and dentin (p < 0.05). CONCLUSIONS: Based on the in vitro study results, we can conclude that RT substantially changes the morphological surface of enamel and dentin and impairs the bond strength. The Clearfill system yielded better results than Adper Single Bond 2, and restoring teeth before RT resulted in the worst results in both substrates.


Asunto(s)
Adhesivos/efectos de la radiación , Esmalte Dental/efectos de la radiación , Recubrimientos Dentinarios/efectos de la radiación , Dentina/efectos de la radiación , Neoplasias de Cabeza y Cuello/radioterapia , Bisfenol A Glicidil Metacrilato/efectos de la radiación , Resinas Compuestas/efectos de la radiación , Recubrimiento Dental Adhesivo , Dentición Permanente , Neoplasias de Cabeza y Cuello/patología , Humanos , Ensayo de Materiales , Diente Molar/efectos de la radiación , Dosis de Radiación , Distribución Aleatoria , Cementos de Resina/efectos de la radiación , Resistencia al Corte/efectos de la radiación , Fracturas de los Dientes/etiología , Fracturas de los Dientes/patología
14.
Radiat Prot Dosimetry ; 186(1): 94-112, 2019 Dec 31.
Artículo en Inglés | MEDLINE | ID: mdl-31840174

RESUMEN

ESR (electron spin resonance) can date sites that span the whole Paleolithic, but requires accurate sedimentary dose rates, especially in caves where the internal and cosmic dose rates can approach 0 mGy/yr. This study examines the sedimentary radioactivity in the upper layers at Golema Pest, North Macedonia. Reaching > 5.5 m deep, > 21 flatly lying, silty-sandy matrix-supported gravel layers with éboulis clasts fill the cave. In Sondage 2, Layers 0-5 contained many hearths and yielded thousands of bones and teeth, many from ungulates. In Layers 2-5a sat thousands of lithics and small tools, many made on tiny quartz crystals. Layers 2c-6 have Mousterian assemblages with denticulates, notched tools, Levallois cores and flakes. To measure the volumetrically averaged sedimentary dose rates for ungulate teeth dated by ESR from Sondage 2, 66 sediment samples were analyzed by NAA. Adding éboulis, calcined bone, and charcoal associated with the hearths lowered the sedimentary dose rates or left them unchanged. In Layer 2 at 198 cm below the cave datum, the Campanian Ignimbrite (CI) cryptotephra occurred, where it caused abnormally high sedimentary U, Th, and K concentrations and dose rates. Since the CI tephra lay 28-30 cm above AT77, a tooth dated from Layer 3, using time- and volumetrically averaging increased AT77's sedimentary dose rate by 32%, and dropped its calculated age by 25%. Analyzing the sedimentary compositions at every 2 cm in Layers 0-2 yielded a highly detailed stratigraphy that reduced the uncertainty in the sedimentary dose rates and the ESR ages, but more detailed geochemical analyses must be completed within the lower layers in Sondage 2.


Asunto(s)
Esmalte Dental/efectos de la radiación , Espectroscopía de Resonancia por Spin del Electrón/métodos , Sedimentos Geológicos/análisis , Paleontología/métodos , Monitoreo de Radiación/métodos , Datación Radiométrica/métodos , Animales , Huesos , Cuevas , Fósiles , Grecia , Humanos , Mamíferos , Dosis de Radiación
15.
J Microsc ; 276(2): 89-97, 2019 11.
Artículo en Inglés | MEDLINE | ID: mdl-31691278

RESUMEN

Samples of enamel and dentin from human molar teeth were heated in air from room temperature (25°C) up to 1200°C and the phase transition from hydroxyapatite (HAP) to tricalcium phosphate (ß-TCP) was recorded. The changes produced in morphology and chemical composition in the tooth during heating were analysed by light microscopy, scanning electron microscopy (SEM), characteristic x-ray energy dispersion spectroscopy (EDS), x-ray diffraction (XRD), electron diffraction, transmission electron microscopy (TEM) and high-resolution electron microscopy (HRTEM). The results indicated a high correlation relationship among Ca content, P content, O content and Na content, and the existence of the Kirkendall effect during the HAP- ß-TCP phase transition. LAY DESCRIPTION: This work is related with tooth materials. Samples of enamel and dentine from human molar teeth were heated in air from 25°C up to 1200°C and the phase transition from hydroxyapatite (HAP) to tricalcium phosphate (ß-TCP) was recorded. The ß-TCP phase is also known as whitlockite. The changes produced in morphology and chemical composition in the tooth during heating were analysed by electron microscopy and X-ray diffraction. The results indicated a high correlation relationship among Ca, P, O and Na contents, and the existence of the Kirkendall effect, the atomic diffusion producing voids, during the HAP- ß-TCP phase transition.


Asunto(s)
Materiales Biocompatibles/efectos de la radiación , Fosfatos de Calcio/efectos de la radiación , Durapatita/efectos de la radiación , Microscopía Electrónica , Diente Molar/efectos de la radiación , Transición de Fase/efectos de la radiación , Esmalte Dental/efectos de la radiación , Dentina/efectos de la radiación , Calor , Humanos , Análisis Espectral
16.
Microsc Res Tech ; 82(11): 1869-1877, 2019 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-31373738

RESUMEN

Laser irradiation has been proposed as a preventive method against dental caries since it is capable to inhibit enamel demineralization by reducing carbonate and modifying organic matter, yet it can produce significant morphological changes. The purpose of this study was to evaluate the influence of Er:YAG laser irradiation on superficial roughness of deciduous dental enamel and bacterial adhesion. Fifty-four samples of deciduous enamel were divided into three groups (n = 18 each). G1_control (nonirradiated); G2_100 (7.5 J/cm2 ) and G3_100 (12.7 J/cm2 ) were irradiated with Er:YAG laser at 7.5 and 12.7 J/cm2 , respectively, under water irrigation. Surface roughness was measured before and after irradiation using a profilometer. Afterwards, six samples per group were used to measure bacterial growth by XTT cell viability assay. Adhered bacteria were observed using confocal laser scanning microscopy (CLSM) and a scanning electron microscopy (SEM). Paired t-, one-way analysis of variance (ANOVA), Kruskal-Wallis and pairwise Mann-Whitney U tests were performed to analyze statistical differences (p < .05). Before treatment, samples showed homogenous surface roughness, and after Er:YAG laser irradiation, the surfaces showed a significant increase in roughness values (p < .05). G3_100 (12.7 J/cm2 ) showed the highest amount of Streptococcus mutans adhered (p < .05). The increase in the roughness of the tooth enamel surfaces was proportional to the energy density used; the increase in surface roughness caused by laser irradiation did not augment the adhesion of Streptococcus sanguinis; only the use of the energy density of 12.7 J/cm2 favored significantly the adhesion of S. mutans.


Asunto(s)
Adhesión Bacteriana/efectos de la radiación , Caries Dental/prevención & control , Esmalte Dental/efectos de la radiación , Láseres de Estado Sólido/uso terapéutico , Streptococcus mutans/fisiología , Streptococcus/fisiología , Adhesión Bacteriana/fisiología , Humanos , Microscopía Electrónica de Rastreo , Streptococcus/crecimiento & desarrollo , Streptococcus/efectos de la radiación , Streptococcus mutans/crecimiento & desarrollo , Streptococcus mutans/efectos de la radiación , Streptococcus sanguis , Propiedades de Superficie/efectos de la radiación
17.
Photobiomodul Photomed Laser Surg ; 37(7): 428-433, 2019 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-31265378

RESUMEN

Objective: Evaluate the bond strength of repairs made on composite resin following the treatment of the surface of the flaw with different bonding agents and/or CO2 laser. Background: The influence of CO2 laser and its interaction with other bonding agents on the surface of the flaw is not yet known. In this study, CO2 laser was chosen to treat the surface of the flaw due to its capacity to promote irregularities on the surface that enhance mechanical micro-retention. Methods: A block was created with Vitra APS nanohybrid composite resin (color: A3; FGM, Joinville, Brazil) measuring 5 mm in width, length, and depth (volume: 125 mm3). The surface of the flaw was treated before the repair with an adhesive, silane bonding agent, and/or CO2 laser. Six specimens were created in composite resin for each group (total: n = 36): G1: resin+resin; G2: adhesive+resin; G3: laser+adhesive; G4: laser+silane+adhesive; G5: silane+adhesive; G6: laser+silane. After the repair, the surfaces of the fracture of all specimens, which were submitted to the microtraction test, were analyzed under an optical microscope. Bond strength values obtained according to the type of surface treatment were tabulated and submitted to the Kruskal-Wallis test. Dunn's test was used to compare means. Results: G3 and G4 had significantly higher bond strength values compared to all other groups tested. Adhesive fractures predominated in all groups. However, G3 and G4 had a higher percentage of cohesive fractures compared to the other groups. Conclusions: The application of CO2 laser as a surface treatment led to greater bond strength of composite resin repairs in comparison with the groups that only received treatment with a burr and silanization. The groups submitted to CO2 laser also had a significantly lower number of adhesive failures when submitted to the microtraction test.


Asunto(s)
Resinas Compuestas/química , Recubrimiento Dental Adhesivo , Esmalte Dental/efectos de la radiación , Grabado Dental/métodos , Materiales Dentales/química , Láseres de Gas , Dióxido de Carbono , Análisis del Estrés Dental , Recubrimientos Dentinarios/química , Ensayo de Materiales , Resistencia al Corte/efectos de la radiación , Estrés Mecánico , Propiedades de Superficie
18.
Radiat Prot Dosimetry ; 186(1): 48-53, 2019 Dec 31.
Artículo en Inglés | MEDLINE | ID: mdl-31120538

RESUMEN

The method of electron spin resonance (ESR) tooth enamel dosimetry was successfully applied to cattle molar teeth exposed in the accident of Fukushima Dai-ichi atomic power plants. Total of 10 samples from 5 cattle were examined and the doses were retrospectively reconstructed to be up to 1.2 Gy (enamel dose). The dose values are roughly consistent with those estimated from the monitored environmental dose rate and the durations of the exposure. This first successful result on ESR reconstruction of doses in the actual radiation accident indicates that ESR tooth enamel dosimetry with cattle is practically useful in the dose range of ~1 Gy.


Asunto(s)
Esmalte Dental/efectos de la radiación , Espectroscopía de Resonancia por Spin del Electrón/métodos , Accidente Nuclear de Fukushima , Monitoreo de Radiación/métodos , Ceniza Radiactiva/análisis , Animales , Bovinos , Centrales Eléctricas , Dosis de Radiación , Estudios Retrospectivos
19.
J. oral res. (Impresa) ; 8(2): 131-139, abr. 30, 2019. tab, ilus, graf
Artículo en Inglés | LILACS | ID: biblio-1145313

RESUMEN

Purpose: De-bonding strength of ceramic veneers by laser use needs to be evaluated in detail. The aim of this study, is to determine the contribution of ceramic thickness and cementing agents to the de-bonding strength of ceramic veneers using Er,Cr:YSGG laser. Methods: A total of 120 maxillary central incisors specimens were randomly divided into twelve groups on the basis of disc thickness, cementing agent, and Er,Cr:YSGG laser use. Under laboratory conditions, 120 IPS Empress II system discs 0.5mm, 1mm, and 2mm in thickness were applied to the tooth surfaces, for laser use. An Er,Cr:YSGG laser system was applied to the central surface of the IPS Empress II discs on specimens in all laser groups (Groups 1,3,5,7,9,11). Then the shear bond strength (SBS) for all specimens were tested with a testing machine at a speed of 0.5mm/min. The SBS values were considered as the de-bonding strength. Results: The mean de-bonding strength values for Groups 9 and 11 (0,5 mm disc thickness + laser application) have the lowest median load (0.000 N), while Group 4 (2mm disc thickness + no laser) has the highest median load (573.885 N). The de-bonding strengths of all the groups without laser application were higher than those of all groups with laser use. When laser is applied, the mean de-bonding strength decreases with decreasing disc thickness, and it reaches zero at 0.5mm thickness of discs cemented by self- or total-etch adhesives. Conclusions: The de-bonding strength decreases with laser use, and decreasing disc thickness. In the absence of laser, the mean de-bonding values of discs cemented by a total etch adhesive system are always higher than those of discs cemented with a self-etch adhesive system. Without any extra load, all 0.5mm thick discs were dislodged from teeth while applying or testing the laser.


Propósito: La resistencia de desunión de las carillas de cerámica mediante el uso del láser debe evaluarse en detalle. El objetivo de este estudio es determinar la contribución del espesor de la cerámica y los agentes de cementación a la resistencia de desunión de las carillas de cerámica utilizando el láser Er, Cr: YSGG. Métodos: Un total de 120 incisivos centrales maxilares se dividieron al azar en doce grupos según el grosor del disco, el agente de cementación y el uso del láser Er, Cr: YSGG. En condiciones de laboratorio, se aplicaron en las superficies de los dientes 120 discos del sistema IPS Empress II de 0,5mm, 1mm y 2mm de grosor, para uso con láser. Se aplicó un sistema láser Er, Cr: YSGG a la superficie central de los discos IPS Empress II en muestras de todos los grupos de láser (Grupos 1,3,5,7,9,11). Luego, la resistencia de la unión al cizallamiento (SBS) para todas las muestras se probó con una máquina de prueba a una velocidad de 0.5mm/min. Los valores de SBS se consideraron como la fuerza de desunión. Resultados: Los valores medios de resistencia de desunión para los Grupos 9 y 11 (espesor de disco de 0,5mm + aplicación de láser) demostró la carga media más baja (0,000 N), mientras que el Grupo 4 (espesor de disco de 2 mm + sin láser) tuvo la carga media más alta (573.885 N). Las fuerzas de desunión de todos los grupos sin aplicación de láser fueron superiores a las de todos los grupos con uso de láser. Cuando se aplica el láser, la fuerza media de desunión disminuye al disminuir el grosor del disco, y llega a cero con el grosor de 0,5mm de los discos cementados, para ambos adhesivos de grabado. Conclusiones: la fuerza de desunión disminuye con el uso del láser y disminuye con el grosor del disco. En ausencia de láser, los valores medios de desunión de los discos cementados con un sistema de adhesivo de grabado total son siempre más altos que los de los discos cementados con un sistema de adhesivo de autograbado. Sin ninguna carga adicional, todos los discos de 0,5mm de grosor se desprendieron de los dientes al aplicar el láser.


Asunto(s)
Humanos , Cerámica/uso terapéutico , Recubrimiento Dental Adhesivo , Resistencia al Corte , Láseres de Estado Sólido/uso terapéutico , Esmalte Dental/efectos de la radiación , Materiales Dentales/química , Coronas con Frente Estético
20.
Health Phys ; 116(6): 799-806, 2019 06.
Artículo en Inglés | MEDLINE | ID: mdl-30889104

RESUMEN

The goal of the study was to establish characteristics of Japanese wild boar tooth enamel in the dose region of 0.25-2.0 Gy and to reconstruct external absorbed doses to wild boar native to the Fukushima exclusion zone using electron paramagnetic resonance dosimetry. The significance of Japanese wild boar in their ecosystem and their position within the trophic hierarchy make the wild boar a species of particular importance and therefore, the focus of this study. Dose response linearity and variability of enamel originating from various wild boar were investigated. Radiation dose response of Japanese wild boar tooth enamel in the range of 0.25-2.0 Gy was found to be linear, and the average variation in dose response between teeth originating from the same boar specimen was nearly 30%. No statistically significant difference in dose response was found based on sex of the boar or in permanent molar teeth of boar of differing ages. Electron paramagnetic resonance absorbed doses to boar tooth enamel were successfully reconstructed using the calibration curve method and converted into estimates of absorbed dose to soft tissue with large associated confidence intervals. The critical level dose value for the calibration curve was 1.0 Gy and the detection limit dose was 1.8 Gy, suggesting that this method would be more beneficial for boar with lifetime absorbed doses greater than 1.0 Gy. The method of reconstructing external absorbed doses using electron paramagnetic resonance dosimetry with tooth enamel from Japanese wild boar as dosimeters has proven to be a viable method which can be used to reconstruct absorbed doses to wildlife in accident-stricken areas in the absence of alternative dosimetry.


Asunto(s)
Esmalte Dental/efectos de la radiación , Espectroscopía de Resonancia por Spin del Electrón/métodos , Rayos gamma/efectos adversos , Monitoreo de Radiación/métodos , Diente/efectos de la radiación , Animales , Ecosistema , Accidente Nuclear de Fukushima , Dosis de Radiación , Sus scrofa
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