Comparative study of methods for the quantification of biofilm on complete dentures

Abstract

This study compared the application and reliability of 4 methods for biofilm quantification (computerized, paper-weighing, point-counting, and planimetric) in complete dentures, verifying the correlation between them. The internal surfaces of 62 complete dentures were stained (5% erythrosine) and photographed. The slides were projected on paper, and the areas (total and biofilm-covered) were outlined with a pencil. These areas were measured with an equidistant point grid (point-counting method), a digital planimeter (planimetric method), and for the paper weighing method they were cut and weighed with a precision scale. For the computerized method, ImageTool software was used. In order to perform a validation test of the methods, all of them were applied to slide projections of geometric figures with known dimensions. The correlation tests showed high correlation values (r = 0.82 to 0.99) among the methods. The validation test (ANOVA) showed no statistically significant differences among the values obtained from the measurement of figures using all four quantitative methods and the real dimensions of these geometric figures. Quantitative methods were efficient and reliable for measuring quantity of biofilm in complete dentures, and may be useful in experimental studies on the efficacy of hygiene products. The computerized method was fast and easy to perform. DESCRIPTORS: Denture, complete; Biofilms. RESUMO:Este estudo comparou a aplicação e a confiabilidade de quatro métodos de quantificação de biofilme (computadorizado, pesagem de papel, contagem de pontos e planimétrico) em próteses totais, verificando a correlação entre eles. As superfícies internas de 62 próteses totais foram coradas (eritrosina a 5%) e fotografadas. Os diapositivos foram projetados em papel, e as áreas (total e com biofilme corado) foram contornadas com grafite. Estas áreas foram medidas com uma grade de pontos eqüidistantes (método de contagem de pontos), um planí-metro digital (método planimétrico) e, para o método de pesagem de papel, foram recortadas e pesadas em balança de precisão. No método computadorizado, foram medidas com um software (ImageTool). Com o objetivo de realizar um teste de validação dos quatro métodos, estes foram aplicados também em diapositivos de figuras geométricas de dimensões conhecidas. Os testes de correlação mostraram altos valores de correlação (r = 0,82 a 0,99) entre os métodos. O teste de validação (ANOVA) não mostrou diferença estatisticamente significante entre as medidas reais dos desenhos geométricos e aquelas obtidas pelos quatro métodos quantitativos. Os métodos quantitativos mostraram-se eficazes e confiáveis na mensuração dos níveis de biofilme em próteses totais, podendo ser úteis em estudos experimentais da eficiência de produtos de higiene. O método computadorizado mostrou-se rápido e de fácil aplicação.

The effectiveness of chemical denture cleansers and ultrasonic device in biofilm removal from complete dentures

“…Previous analyses by the photographic method, used for comparing total surface areas (internal and external) of complete dentures, showed high correlation coefficients 19 . According to the study of Paranhos and Silva-Lovato 19 (2004), biofilm quantification performed by photographic and computerized methods, offer objective and accurate results, and should therefore be the methods of choice in clinical experiments for the evaluation of complete denture cleansers.…”

“…In the present study, the photographic method associated with a computerized method of biofilm quantification was chosen. The first method mentioned above was chosen because quantification by visual inspection 1 is known to be difficult and the second method mentioned was chosen because it relies on calibration 19 .…”

“…According to the study of Paranhos and Silva-Lovato 19 (2004), biofilm quantification performed by photographic and computerized methods, offer objective and accurate results, and should therefore be the methods of choice in clinical experiments for the evaluation of complete denture cleansers. It is important to emphasize that although the computerized method was shown to be reliable for measuring biofilm on complete dentures, it has the important limitation of requiring a longer amount of time spent on making the measurements.…”

Effects of mechanical and chemical methods on denture biofilm accumulation

“…The use of neutral red solution is justified by its high affinity to oral biofilms and the ease of removal (38). In addition, photography (36) combined with quantitative analysis (37) was employed to obtain an objective evaluation. A limitation of most biofilm measurement techniques, including the present method is the two‐dimensional nature of recording.…”

Clinical and antimicrobial efficacy of NitrAdineTM-based disinfecting cleaning tablets in complete denture wearers

“…The use of neutral red solution is justified by its high affinity to oral biofilms and the ease of removal 31 . In addition, photography 1 combined with quantitative analysis 21 was employed to standardize an objective evaluation method. A limitation of most biofilm measurement techniques, including the present method is the two dimensional nature of the recording.…”