Dental caries prophylaxis with photosensitizers (experimental, laboratory and clinical studies) // Профилактика на зъбния кариес с фотосенсибилизатори (експериментални, лабораторни и клинични изследвания)

[EN] Dental caries is a social, multietiological bacterially-mediated disease with significant consequences for the oral and the overall health of the human population. Diseases related to microbial biofilms are one of the most prevalent bacterial diseases in humans. The process of destruction of hard dental tissues due to dental caries is part of these conditions of disturbed ecological balance. The role of Mutans Streptococci (MS) and Lactobacilli, as an essential part of the biofilm on the hard dental tissues and their involvement in the emergence of carious process widely recognized. The use of antimicrobial agents and agents for chemical inhibition is a valuable addition to the methods of mechanical plaque control. However the side effects and the drawbacks of these agents prevent their long-term use. Antibiotics are effective in reducing caries activity in animals and in humans, but clinically irrelevant for the prevention. One of the innovative methods for controlling biofilm-induced diseases is the Antibacterial photodynamic therapy (APDT). Although the process of photodynamic inactivation of microorganisms existed since 1900, only in the last 25 years, the scientific community once again directs its efforts towards this method, which is an alternative to conventional antimicrobial therapy. Destruction of biofilms by APDT requires application of visible light of a specific wavelength in order to excite the sensitizing agent, and to generate cytotoxic complexes, which may cause a lethal effect on the bacteria in the biofilm. There is a need for a suitable and convenient light source that can be used to irradiate all tooth surfaces. AFDT method is still in its experimental stage and is gradually becoming a method of choice, mostly for the treatment of localized infections. Biofilm-induced diseases: periodontitis, periimplantitis, periapical infectious and dental caries are particularly suitable for the prevention and treatment AFDT as fully meet the requirements for application of the method: Controlled introduction of photosensitizer in the biofilm; easy access of light and opportunity for its topical guide; spatially limiting the impact. In this study we investigated the possibilities of an innovative approach to control cariogenic biofilm based on increasingly trending AFDT as an alternative to a conventional antibiotics and antiseptics, especially in areas where there is need and opportunity for local response. In our scientific work we investigated the possibilities of three metal phthalocyanine dyes - Zn-, Si-, Ga-metal phthalocyanin and two dyes approved for clinical use - methylene blue and toluidine blue. The product licensed for clinical use is Fotosan® (active substance toludin blue). We confirmed its efficiency on a reference laboratory strain S. mutans and on a clinically isolated strain, as well as in vivo administration limiting the mass of the biofilm, in the early stages of its structuring. We were able to compare the efficacy of APDT at various time intervals of light activation and different concentrations of the active substance. We confirmed the effectiveness of the synthesized in our country Zn-phthalocyanine on laboratory reference strain of S. mutans and defined concentration and time parameters of effectiveness on clinical isolate of S. mutans and S. species. We found that there is significant dark toxicity of one synthesized in our country 5-6μM GA-phthalocyanine, which was rejected as a potential agent for caries prevention. We found the effectiveness of Methilen blue on a reference laboratory strain of S.mutans, as in the experiment changed substantially the period of incubation time as described in the litterature. In all studies, the light source for APDT was LED. Target microorganisms were: S. mutans - a reference laboratory strain, S. mutans and Streptococci species - isolated from the dental biofilm. We studied in vivo the effect of AFDT with FS® and Methylen blue dental biofilm early stage - up to 72 hours. For the purposes of our clinical research we modified a plaque index and objectified its capabilities. Along with these laboratory and clinical studies we performed a questionnaire survey. The survey results revealed a lack of systematic anti-caries approach, ignorance of APDT, but necessity to introduce an innovative method to control biofilm. Parallel to this we found a need to reduce the time for clinical prevention. Obtained from the in vivo and in vitro research results allow the hypothesis that if in the very early stages of biofilm structure Mutans Streptococci are excluded and Streptococci species preserved (results of our third task), the incorporation of the MS in the structure of the created biofilm will be strongly hampered.

Authors dc:creator

• Doychinova, Maya
• Дойчинова, Мая

• Caries prevention; prophylaxis
• photosensitizer; Methylene Blue; FotoSun®; Antibacterial photodynamic therapy
• Консервативно зъболечение / Conservative Dentistry

Repository record dc:identifier

http://repository.mu-varna.bg/handle/nls/68

OAI identifier oai:identifier

oai:repository.mu-varna.bg:nls/68