Effect of different light-curing techniques on hardness of a microhybrid dental composite resin

Coordenação de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)

Effect of two formulations of 10% sodium ascorbate on fracture resistance of endodontically treated tooth submitted to dental bleaching with hydrogen peroxide associated titanium dioxide nanoparticles

Purpose: This study evaluated the effect of 10% sodium ascorbate (10SA), in gel (10SAg) or aqueous solution (10SAs) formulations, on fracture resistance of endodontically treated tooth submitted to dental bleaching procedures with 15% hydrogen peroxide associated with titanium dioxide (15HP-TiO2) nanoparticles and photoactivated by LED-laser. Material and methods: Forty maxillary premolars were endodontically-treated and embedded in acrylic resin up to the cement-enamel junction. The specimens were divided into four groups (n=10): G1 (negative control): no bleaching, coronal access restored with composite resin; G2 (positive control): three dental bleaching sessions using 15HP-TiO2 and LED-laser photoactivation and restored with composite resin (positive control); G3 (10SAg): similar procedures to G2, but applied 10SA, in gel formulation, for 24 hours before restoration; G4 (10SAs): similar procedures to G3, but applied 10SA, in aqueous solution formulation. The 15HP-TiO2 was applied on buccal and lingual surfaces of the crown tooth and inside the pulp chamber and photoactivated by LED-laser. Between each bleaching session, the teeth were maintained in artificial saliva, at 37oC, for 7 days. In sequence, the teeth were submitted to fracture resistance testing using an eletromechanical machine test. The data was analyzed using Kruskal Wallis test (p = 0.05) Results: There are no differences significant among the groups in relation to fracture resistance of endodontically treated teeth (p>0.05). Conclusions: The use of 10% sodium ascorbate, in gel or aqueous solution formulations, did not interfered on the fracture resistance teeth after dental bleaching using 15HP-TiO2 and LED-laser photoactivation.

Correlación entre diferentes métodos de evaluación de color en el clareamiento dental. Correlation between different methods for co

The aim of this study was to evaluate the correlation of color change on bleaching tooth through delta E (ΔE) by the spectrophotometer Spectroshade (SS) and digital program Scanwhite (SW). Methods: 25 patient volunteers were recruited from Operative Dentistry at Universidad de Chile Dental School, between 18 to 30 years, with good oral hygiene. Exclusion criteria: Previous experienced tooth bleaching, anterior restorations, cervical lesions, pain dental, pregnant patient, stained teeth, malposition of the teeth and periodontal pathology. The bleaching was made in two sessions with three different bleaching systems which were randomly. The assessment of color change through ΔE was made on the two upper central incisors (N=50) by the SS and SW. The color in the same teeth were measured before (T0) and after (T1) of the bleaching treatment. Data were analyzed using test Spearman correlation coefficient (Rho) with a significant level of 95%. Results: The results showed a positive and significant correlation (0.676), with a statistically significant difference (p<0.05). Conclusion: There is correlation in the measurement of color change on bleaching tooth by SS and SW.

Human dental enamel and dentin structural effects after Er:yag laser irradiation

Ideally projected to be applied on soft tissues, infrared lasers were improved by restorative dentistry to be used in hard dental tissues cavity preparations-namely enamel and dentin. This paper evidentiates the relevant aspects of infrared Erbium laser's action mechanism and its effects, and characterizes the different effects deriving from the laser's beams emission. The criteria for use and selection of optimal parameters for the correct application of laser systems and infuence of supporting factors on the process, such as water amount and its presence in the ablation process, protection exerted by the plasma shielding and structural factors, which are indispensable in dental tissues cavity preparation related to restorative technique, are subordinated to optical modifcations caused by the interaction of the energy dissipated by these laser light emission systems in the targeted tissue substrate. Clinical relevance: Differences in the action of infrared Erbium laser system in regard to the nature of the ablation process and variations on the morphological aspects observed in the super-fcial structure of the target tissue irradiated, may be correlated to the structural optical modifcations of the substrate produced by an interaction of the energy propagated by laser systems.

Application of Er:YAG and Er, Cr:YSGG lasers in cavity preparation for dental tissues: a literature review

The laser has been widely used in many specialties of dentistry and several wavelengths have been investigated as a substitute for high-speed handpiece. The purpose of this paper is to review the literature about the use of Er:YAG and Er,Cr:YSGG lasers in cavity preparation for dental tissues. Despite the differences in wavelength, pulse duration and energy, the morphological characteristics of the irradiated dentin surface with these lasers are comparable, as well as its effects as methods of dental caries prevention. Thus, Er:YAG and Er,Cr:YSGG lasers prepared cavities with similar effects on the dental tissue, however, further investigations about ideal irradiation conditions are needed for both lasers.

Surface roughness analysis of dental ceramics treated with hydrofl uoric acid and aluminum oxide jet

The aim of this study was to evaluate the surface roughness of 5 indirect restorative materials treated with hydrofluoric acid to 10%, with aluminum oxide jet and a combination of both. The specimens was prepared with 10 mm in diameter and 2 mm thickness, divided into fi ve groups: (1) Ceromer (CeseadII-Kuraray), (2) Leucite crystals ceramics (IPS EmpressIIIvoclarforcasket), (3) glass ceramic with fluorapatite (IPS D. Sign-Ivoclar), (4) lithium disilicate ceramic (IPS Empress II-Ivoclar restorations), (5) ceramics (Cergogold-Degussa). For all groups were performed the controls, and the surfaces with the 3 types of treatment. For testing roughness used the rugosimeter Taylor/Hobson-Precision, model form tracerSV-C525 high sensitivity. After confi rmation of variance analysis with a signifi cance level of 1% (p < 0.01), there was equality between the average roughness of materials from groups 1, 3 and 5, and the group 2 was different from the others. It was also found that the ceramics of the group 5 behaved similar to group 4. However the lowest average roughness was observed in group 2 ceramic. In the evaluation between the types of treatment, the aluminum oxide jet and associations and blasting with hydrofl uoric acid were similar, and different isolated hydrofl uoric acid, and 3 types of treatment signifi cantly higher than the control group. All treatments promoted superfi cial alterations in all tested materials.

In-Office dental bleaching efficacy assessment in function of the light exposure regime by digital colometric reflectance spectroscopy

In-office dental bleaching has been subject of several studies. Generally those studies quantify through visual analysis, the shade reduction of the teeth submitted to different bleaching protocols (light sources, bleaching agent concentrations and irradiation time). The objective of this work is the determination of the influence of four irradiation protocols on the obtainment of better aesthetic results using a colorimetric spectrophotometer that quantifies color changes in each situation imposed. Forty bovine incisors were selected in function of similar anatomic characteristics; a concentrated coffee solution was used to stain the teeth. A commercial spectrophotometer was used to measure the color changes during evolution of the experiment (stain and bleaching phases) and the obtained data was analyzed by the ANOVA test. The obtained data showed the evolution of teeth color during the staining period, as well as, the color reduction that each bleaching protocol achieved. Based on our findings it is possible to conclude that bleaching protocols with larger irradiation periods did not showed significant differences when compared with shorter irradiation protocols, in that way the use of protocols with 30 min or more of consecutive irradiation are not clinically justified and also can cause several side effects.

Thermal and structural properties of commercial dental resins light-cured with blue emitting diodes (LEDs)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Evaluation of dental restorations: a comparative study between clinical and digital photographic assessments

The aim of this study was to compare the efficacy of a direct clinical evaluation method with an indirect digital photographic method in assessing the quality of dental restorations. Seven parameters (color, occlusal marginal adaptation, anatomy form, roughness, occlusal marginal stain, luster, and secondary caries) were assessed in 89 Class I and Class II restorations from 36 adults using the modified US Public Health Service/Ryge criteria. Standardized photographs of the same restorations were digitally processed by Adobe Photoshop software, separated into the following four groups and assessed by two calibrated examiners: Group A: The original photograph displayed at 100%, without modifications (IMG100); Group B: Formed by images enlarged at 150% (IMG150); Group C: Formed by digital photographs displayed at 100% (mIMG100), with digital modifications (levels adjustment, shadow and highlight correction, color balance, unsharp Mask); and Group D: Formed by enlarged photographs displayed at 150% with modifications (mIMG150), with the same adjustments made to Group C. Photographs were assessed on a calibrated screen (Macbook) by two calibrated clinicians, and the results were statistically analyzed using Wilcoxon tests (SSPS 11.5) at 95% CI. Results: The photographic method produced higher reliability levels than the direct clinical method in all parameters. The evaluation of digital images is more consistent with clinical assessment when restorations present some moderate defect (Bravo) and less consistent when restorations are clinically classified as either satisfactory (Alpha) or in cases of severe defects (Charlie). Conclusion: The digital photographic method is a useful tool for assessing the quality of dental restorations, providing information that goes unnoticed with the visual-tactile clinical examination method. Additionally, when analyzing restorations using the Ryge modified criteria, the digital photographic method reveals a significant increase of defects compared to those clinically observed with the naked eye. Photography by itself, without the need for enlargement or correction, provides more information than clinical examination and can lead to unnecessary overtreatment.

ScanWhite©: método objetivo para avaliação do nível de clareamento dental

A comparação visual com escalas de cor, universalmente empregada para avaliar o resultado das diferentes substâncias, técnicas e aparelhos utilizados no clareamento dental, tem se mostrado um método limitado, questionável, subjetivo e pouco confiável. Os métodos instrumentais, que utilizam espectroscópios ou imagens digitais, têm se mostrado mais adequados por oferecerem avaliações objetivas, maior reprodutibilidade e confiabilidade. Neste artigo, serão apresentados e discutidos os resultados obtidos com a utilização do ScanWhite© ? software para avaliação objetiva do nível de clareamento dental e apoio à decisão clínica, que baseia sua avaliação no processamento computacional de imagens digitais. Esse tem como principais diferenciais: (1) algoritmo calibrador para compensar as variações de luminosidade do ambiente, (2) apresentação dos resultados em valores numéricos e através do gráfico de evolução do clareamento dental, (3) interface intuitiva e facilidade de uso, (4) determinação dos índices de apoio à decisão (IPS ? índice de possibilidade de sucesso, e IRS ? índice de risco de sensibilidade antes do início do tratamento) e (5) emissão de relatório geral, autorizações e recomendações pós-clareamento.

Conhecimento de cárie dental e doença periodontal de professores do ensino fundamental segundo o tipo de instituição (pública ou privada)

Aim: observe the knowledge of dental caries and periodontal disease of primary schoolteachers, according to type of institution (public and private) from Araraquara city. methodology: for that participants were 113 teachers from public schools and 57 from private schools. The instrument of analysis was based on a questionnaire with closed and open questions concerning the etiology, prevention and development of dental caries and periodontal disease. Results: 97,3% of public ́s schoolteachers and 91,2% of private ́s schoolteachers answered that they knows what is dental caries, but they didn ́t answer correctly about the caries etiology as being multifactorial and about methods of prevention. Both of schoolteachers (public and private) had more sucessful when answered about bacterial plaque than periodontal disease and yours manifestation. Conclusion: the dental knowledge of schoolteachers in public and private school was evaluated and limited educational programs should be directed to both public and private schoolteachers, in order to increase the level of dental knowledge of them, so that they can act as educational agents with the children.

Musculoskeletal disorders in upper limbs in dental students: exposure level to risk factors

Aim: This study assessed the risk factors of undergraduate students to develop musculoskeletal disorders (MSD) in the upper limbs, regarding gender, type of dental clinical procedure, mouth region treated, and the four-handed dentistry practice. Methods: Dental students enrolled in the 8th semester in the Araraquara School of Dentistry, UNESP, Brazil, were photographed while practicing 283 dental procedures. The Rapid Upper Limb Assessment (RULA) method was used to evaluate the working postures of each student. The photographs were evaluated and a final risk score was attributed to each analyzed procedure. The prevalence of risk factors of developing MSD was estimated by point and by 95% confidence interval. The association between the risk factor of developing disorders and variables of interest were assessed by the chi-square test with a significance level of 5%. Results: The risk factors of developing MSD were high, regarding most dental procedures performed by the undergraduate students (score 5: 7.07%, CI95%: 4.08- 10.06%; score 6: 62.54%, CI95%: 56.90-68.18%). There was no significant association between the RULA final score and gender (p=0.559), and type of dental procedure (p=0.205), and mouth regions by arch (p=0.110) or hemi-arch (p=0.560), and the use of four-handed dentistry (p=0.366). Conclusions: It can be concluded that gender, type of dental clinical procedure, mouth region treated, and practice of four-handed dentistry did not influence the risk of developing MSD in the upper limbs among the dental students evaluated; however, they are at a high risk of developing such disorders.

Dental anxiety: prevalence and evaluation of psychometric properties of a scale

Aim: To estimate the reliability and validity of the Dental Anxiety Scale (DAS) and identify the prevalence and the effect of the socio-demographic characteristics of dental anxiety, in a sample of 212 adults. Methods: The psychometric sensitivity of the scale was assessed. A confirmatory factor analysis was performed, and the convergent validity and internal consistency were determined. The prevalence of anxiety was estimated, and the effect of socio-demographic variables on anxiety was assessed using structural equation modelling. Results: The participants’ mean age was 33.5 (SD = 15.6) years, and 62.3% were female. There was an adequate factorial adjustment of the scale in this sample. The convergent validity and internal consistency were adequate in the one-factor model. Regarding two-factor model, there was a high correlation (r) among the factors, which jeopardized the discriminant validity. A total of 47.6% of the participants (IC95% = 40.9 - 54.4) presented low levels of anxiety, 32.5% (IC95% = 26.2 - 38.9) moderate levels, and 12.3% (IC95% = 7.8 - 16.7) exacerbated levels. There was a non-significant effect of gender, age and education on the anxiety levels of this sample. Conclusion: We concluded that the one-factor model presented better psychometric qualities, that anxiety was highly prevalent and there was no significant effect of the demographic variables on anxiety, in this sample

Risk muskuloskeletal disorders in upper limbs in dental students: concordance of different methods for estimation of body angle

The purpose of this paper was to evaluate the agreement among different methods used to estimate angular deviation of the body to determine the risk for development of upper limb musculoskeletal disorders in dentistry undergraduates. Materials and Methods: Students (n = 79) enrolled in the final year undergraduate course of the Araraquara School of Dentistry-Sγo Paulo State University-UNESP were evaluated. Photographs were taken of students performing clinical procedures. The work postures adopted by each student were evaluated by means of rapid upper limb assessment (RULA). The basis used to obtain the individual's final risk score is the measurement of the angular deviations in the neutral positions of the regions evaluated. Two methods were used to estimate the angular deviation of the body: Visual exam and Image Tool software. A RULA final risk score was attributed to each procedure the student performed (n = 333). Study of the agreement between the methods about risk of musculoskeletal disorders was conducted by means of Kappa (κ) statistics. The level of significance adopted was 5%. Results: Fair agreement (κ = 0.32) between the evaluated methods was verified. Conclusion: The risk for development of upper limb musculoskeletal disorders by dentistry undergraduates evaluated by using RULA was not in agreement with the results obtained by use of visual exam and Image Tool.

Risk of musculoskeletal disorders in upper limbs in dental students: concordance of different methods for estimation of body angle

The purpose of this paper was to evaluate the agreement among different methods used to estimate angular deviation of the body to determine the risk for development of upper limb musculoskeletal disorders in dentistry undergraduates. Materials and Methods: Students (n = 79) enrolled in the final year undergraduate course of the Araraquara School of Dentistry-Sγo Paulo State University-UNESP were evaluated. Photographs were taken of students performing clinical procedures. The work postures adopted by each student were evaluated by means of rapid upper limb assessment (RULA). The basis used to obtain the individual's final risk score is the measurement of the angular deviations in the neutral positions of the regions evaluated. Two methods were used to estimate the angular deviation of the body: Visual exam and Image Tool software. A RULA final risk score was attributed to each procedure the student performed (n = 333). Study of the agreement between the methods about risk of musculoskeletal disorders was conducted by means of Kappa (κ) statistics. The level of significance adopted was 5%. Results: Fair agreement (κ = 0.32) between the evaluated methods was verified. Conclusion: The risk for development of upper limb musculoskeletal disorders by dentistry undergraduates evaluated by using RULA was not in agreement with the results obtained by use of visual exam and Image Tool.