Inovações em materiais odontológicos antimicrobianos e estratégias clínicas para o controle da cárie: desenvolvimento de materiais, aplicação e abordagens clínicas contemporâneas

Abstract

Dental caries and periodontal disease are the most prevalent pathological processes in the oral cavity. Antimicrobial substances can eliminate or reduce oral bacteria and biofilms related to these diseases. The cashew nut shell liquid (CNSL) and its isolated compounds have been extensively studied for their antibacterial activity. This thesis consists of four chapters, with the following objectives: 1) to evaluate the inhibitory and bactericidal activity of CNSL and its isolated compounds (anacardic acid and cardol) against oral bacteria; to analyze the effect of a dental adhesive incorporated with CNSL, anacardic acid, or cardol on inhibiting the formation of a dual-species biofilm; to assess the physicochemical properties of the adhesive incorporated with these substances; 2) to develop a mouthwash and gel containing anacardic acid for the prevention and control of caries and periodontal disease, respectively; 3) to investigate the clinical management of deep occlusal caries lesions in permanent teeth by Brazilian dentists; 4) to create an e-book on the clinical management of deep carious lesions. In Chapter 1, the antibacterial effect of CNSL, anacardic acid, and cardol was evaluated in vitro by determining the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Additionally, the inhibitory effect of the adhesive incorporated with the substances (15 μg/ml) on a dual-species biofilm composed of Streptococcus mutans and Candida albicans was assessed through a direct contact test. The physicochemical properties of the adhesive incorporated with the substances were determined through tests for elasticity modulus (EM), flexural strength (FS), sorption and solubility (WS/SL), degree of conversion (DC), and microtensile bond strength (μTBS). The data were statistically analyzed using one-way ANOVA and Tukey's test (p < 0.05). In Chapter 2, the development of the mouthwash was carried out using anacardic acid, extracted from CNSL, as the active ingredient, along with the necessary pharmaceutical excipients to ensure good organoleptic characteristics and preservation. The concentration range established varied from 0.0003% to 0.12%, as determined by in vitro microbiological tests (MIC and MBC, biomass quantification, and colony-forming unit counting) against periodontopathogenic bacteria, in addition to toxicological tests (in vivo model using Caenorhabditis elegans and the MTT colorimetric method — 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide — on murine fibroblasts and human keratinocytes). In Chapter 3, a cross-sectional study was conducted with a sample of 732 Brazilian dentists who answered an electronic questionnaire with 20 questions covering sociodemographic information, professional training and activity characteristics, and clinical management of deep carious lesions. In Chapter 4, an e-book was created based on the International Caries Consensus Collaboration (ICCC) and scientific articles published in the last ten years, with the goal of updating Brazilian dentists on the management of deep carious lesions. In Chapter 1, it was found that CNSL, anacardic acid, and cardol exhibited antibacterial activity against all tested strains, with MIC and MBC values ranging from 3.12 to 25 μg/ml. No colony growth was observed in adhesives incorporated with these substances. The EM increased in the adhesive incorporated with anacardic acid, decreased after the incorporation of cardol, and was unaffected by the incorporation of CNSL. The tested substances had no effect on FS, DC, WS, SL, or μTBS. In Chapter 2, the mouthwash containing anacardic acid was effective against biofilms of periodontopathogenic bacteria, even at substantially reduced concentrations, without any manifestation of adverse toxic effects. In Chapter 3, selective caries removal was the strategy most frequently chosen by the majority of dentists (42.8%), and 45.6% of dentists disagreed with maintaining carious tissue over the pulp in deep lesions with a risk of pulp exposure. When using instruments to remove carious dentin, 17% of dentists selected a diamond bur, while 13% preferred tungsten carbide burs. Dentists trained in public institutions, as well as those with a master's or doctoral degree, opted for more conservative treatments. The e-book (Chapter 4) was written, reviewed, approved, and published by the DINCE publishing house. In conclusion, Chapters 1 and 2 demonstrate that the antimicrobial effect of CNSL, cardol, and anacardic acid shows promise for the prevention and control of caries and periodontal disease. In Chapter 3, it is concluded that the dissemination of conservative approaches in the management of deep carious lesions should be intensified, with an emphasis on the use of updated scientific literature.