In vitro antimicrobial activity of irreversible hydrocolloid impressions against 12 oral microorganisms

Abstract

This study evaluated in vitro the antimicrobial activity of irreversible hydrocolloids (one containing an antimicrobial agent) prepared with water or with a 0.2% chlorhexidine digluconate solution against 12 strains of the oral microbiota. Twenty specimens (0.5x1.0 cm) for each group (1. Jeltrate mixed with water; 2. Jeltrate mixed with 0.2% chlorhexidine digluconate solution; 3. Greengel mixed with water; 4. Greengel mixed with 0.2% chlorhexidine digluconate solution) were prepared under sterile conditions and placed in culture media inoculated with the indicator strains. After incubation in aerobiosis or microaerophilia, inhibition of the microbial growth was measured and the results were interpreted. The normal adherence curve revealed a non-normal distribution of the data, so the non-parametric Friedman Test was performed (p<0.05). The antimicrobial activity of the groups was classified in the following order: 1, 3, 4, and 2. The results suggest that the method of preparing irreversible hydrocolloids with a 0.2% digluconate chlorhexidine solution is more effective than the incorporation of an antimicrobial agent in the powder to reduce cross-contamination caused by impressions.

Conducts of disinfection, pouring and storage of irreversible hydrocolloid impressions by undergraduate students

“…From a microbiological standpoint, the use of the immersion technique is most effective when compared with the spray method; however, the immersion can cause dimensional changes of the hydrocolloid mold, due to the imbibition of the disinfecting agent 9 .…”

“…The possibility of contamination between the patient and the dental team by manipulating molds and models, makes it essential to carry out disinfection of the molds as cross-infection control measures [5][6][7] . However, it is necessary that the physico-chemical properties of the molding material, such as the ability to reproduce detail, the dimensional stability and the degree of wetting, are not changed 8,9 . It is important to consider the correct selection of the disinfection method to achieve the goal of cross-infection control, without negatively impacting the dental work 10 .…”

Precisão dimensional de moldes de hidrocoloide irreversível manipulado com solução de clorexidina

“…A autodesinfecção dos moldes de HI, mediante a adição de clorexidina no pó 3,20,21 ou como solução para mistura [7][8][9][10]22 , mostrou-se eficaz na redução da contaminação em muitos estudos. Avaliou-se, nesse experimento, a precisão dimensional dos pilares de modelos de gesso obtidos com moldes de HI contendo diacetato de clorexidina no pó e manipulado com solução aquosa de digluconato de clorexidina a 0,2%.…”

“…O mercado disponibiliza alginatos suplementados com clorexidina, e alguns estudos têm sido feitos utilizando a solução aquosa de digluconato de clorexidina a 0,2% como líquido de mistura [7][8][9] . Essa técnica tem como vantagem específica o combate da contaminação proporcionada pelos microrganismos orais que são facilmente incorporados, no ato da moldagem, durante a geleificação do alginato.…”

“…A imersão ou aplicação do desinfetante como spray proporcionaria somente um efeito superficial 8 . Embora, nas pesquisas que utilizam autodesinfecção do hidrocoloide irreversível com clorexidina, os resultados não atinjam 100% de eficácia antimicrobiana, a redução da contaminação é bastante significativa 7,10 , restando ainda a opção de fazer desinfecção complementar nos modelos de gesso 11 . Outro insucesso clínico, quando do uso de alginato, estaria relacionado com o acondicionamento dos moldes e tempo entre moldagem e vazamento do gesso 12 .…”