Optical clearing agents based on metallic and dielectric nanoparticles for caries diagnostic by optical coherence tomography.

OBJECTIVE: This study aimed to assess the effect of titanium dioxide (TiO2) and silver (Ag) nanoparticles dispersed in glycerol or water, serving as optical clearing agents nanocolloids (OCAs-NC), for improving optical coherence tomography (OCT) images and highlighting incipient lesions in ex vivo human teeth. MATERIALS AND METHODS: Twelve human teeth with incipient lesions were divided into seven groups according to the OCA-NC; they were subjected to G1 (air), G2 (glycerol), G3 (TiO2 0.1%), G4 (TiO2 0.01%), G5 (TiO2 0.001%), G6 (AgNO3 10%), and G7 (AgNO3 100%). The OCA-NC was applied to the occlusal surface, and two-dimensional images of the specimens were analyzed using OCT (930 nm central wavelength; 100 nm bandwidth; 5 mW output power; axial resolution of 7/5.3 µm in water and air, respectively; lateral resolution of 8 µm; and light penetration depth of 1.6 mm inside the sample). RESULTS: The findings demonstrated that the utilization of OCAs-NC containing metallic or dielectric nanoparticles (AgNO3 and TiO2) led to improved differentiation between sound and demineralized enamel on occlusal surfaces. Additionally, it enhanced the depth of image penetration when analyzing this hard tissue with OCT. CLINICAL RELEVANCE: In the current context of minimally invasive dentistry, the use of OCAs-NC in conjunction with OCT can provide clinicians with early diagnosis, allowing for the determination of less/more invasive therapies and consequently halting the disease before cavitation of dental tissues occurs.

Factors associated with gingival bleeding in adolescents / Fatores associados ao sangramento gengival em adolescentes

ABSTRACT Objective: Describe the relationship between gingival bleeding and risk factors (behavioral and psychosocial) in adolescents aged 14 to 19 years in the city of São Lourenço da Mata, Brazil. Methods: An observational, cross-sectional study was conducted with 1154 adolescents aged 14 to 19 years randomly selected from public schools located in the city of São Lourenço da Mata in the state of Pernambuco, Brazil. Socio-demographic (sex, age and race), behavioral (oral hygiene, smoking, alcohol use and leisure activities) and psychosocial (self-esteem and self-perception) data were collected through self-administered questionnaires. The presence/absence of gingival bleeding was determined using the Community Periodontal Index (CPI). The data were submitted to descriptive statistics and Pearson's chi-square test was used to determine associations between risk factors and gingival bleeding, with the significance level set at 5% (p < 0.05). Results: The response rate was 80% of 1418 adolescents initially proposed to compose the sample and the prevalence of bleeding was 50.3%. No associations were found between gingival bleeding and socio-demographic, behavioral or self-esteem factors. Regarding self-perception, a significant association was found between positive attitudes of satisfaction with one's physical appearance and gingival bleeding (p < 0.05). Conclusion: Gingival bleeding was found in most adolescents, but did not exert an influence on the satisfaction these individuals have regarding their physical appearance.

RESUMO Objetivo: Descrever a relação do sangramento gengival com os fatores considerados de risco (comportamentais e psicossociais) em adolescentes de 14 a 19 anos da cidade de São Lourenço da Mata, Pernambuco. Métodos: Foi realizado um estudo observacional de corte transversal, com fonte de dados primários, com 1154 adolescentes de 14 a 19 anos, de ambos os sexos, selecionados de forma randomizada em escolas públicas localizadas no município de São Lourenço da Mata, Pernambuco, Brasil. Foram avaliados dados não-clínicos: sociodemográficos (sexo, idade e raça), comportamentais (frequência de higiene oral, fumo, álcool e atividades de lazer) e psicossociais (autoestima e autopercepção) coletados através de questionários auto-aplicados e dados clínicos: presença e ausência de sangramento gengival através do Índice Periodontal Comunitário (IPC). Os dados foram apresentados de forma descritiva, onde avaliou a associação entre fatores de risco e sangramento gengival e estatística (Qui-Quadrado de Pearson). Para todas as análises foi estipulado um nível de significância de 5%. O estudo teve 80% de taxa de resposta de 1418 adolescentes propostos inicialmente para compor a amostra. Resultados: Constatou-se a prevalência de 50, 3% de sangramento. Não houve associação entre sangramento gengival e fatores sociodemográficos, comportamentais e autoestima. Em relação à autopercepção, foi encontrada associação significante entre atitudes positivas de satisfação com a aparência física e a presença de sangramento (p<0.05). Conclusão: O sangramento gengival ainda está presente em grande parte dos adolescentes, porém nãoinfluencia na satisfação desses indivíduos com a sua aparência física.