Impact of honey on dental erosion and adhesion of early bacterial colonizers.

The aim was to investigate if honey causes erosion and if salivary pellicle modified with honey, or its components, or the by-product propolis has a protective effect against dental erosion and adhesion of early bacterial colonizers. The tested substances were: 3 types of honey, methylglyoxal (MGO), hydrogen peroxide, propolis. First in the erosion experiment, 120 human enamel specimens were covered with salivary pellicle and modified with the substances. Then they were eroded with 1% citric acid, pH 3.6 for 2 min, before surface hardness was measured. In the microbiological assay, the enamel specimens (n = 126) covered with modified salivary pellicle were contaminated with bacterial suspensions. The antimicrobial activity of each substance and their effect on early bacterial colonizer adhesion and biofilm formation were determined. Despite a low pH, honey did not cause erosion. On the other hand, pellicle modification with the tested solutions did not protect the enamel from erosion. Microbiologically, the 3 honeys inhibited species-specific growth of oral bacteria. Propolis decreased initial attachment of Streptococcus gordonii, while one honey inhibited demineralization of enamel by biofilm. In conclusion, pellicle modification with honey, or its components, or propolis did neither protect against erosion nor promote it. Propolis presented some bacterial adhesion inhibition.

The 'sialo-microbial-dental complex' in oral health and disease.

Biofilms are naturally found in all wet environments including the oral structures of nearly all species. Human oral biofilms have existed since our earliest ancestors and have evolved symbiotically with the dentition over many millennia within a Palaeolithic, hunter-gatherer setting. Irrespective of the plant-animal ratio, it can be argued that the Palaeolithic diet was essentially acidic, and acted as a selective force for much of the evolution of the stomatognathic system. The relationship between saliva, biofilm and teeth, the 'sialo-microbial-dental complex', provides oral health benefits and offers a different perspective to the old dental paradigm that only associated oral biofilms (plaque) with disease (caries). This new paradigm emphasises that oral biofilms are essential for the 'mineral maintenance' of teeth. Oral biofilms provide physical protection from dietary acid and together with bacterial metabolic acids cause the resting pH of the biofilm to fall below neutral. This is then followed by the re-establishment of a neutral environment by chemical interactions mediated by the saliva within the biofilm. Such pH fluctuations are often responsible for the cyclic demineralisation, then remineralisation of teeth, a process necessary for tooth maturation. However, since the advent of farming and especially since the industrial revolution, the increase in consumption of carbohydrates, refined sugars and acidic drinks has changed the ecology of biofilms. Biofilm biodiversity is significantly reduced together with a proliferation of acidogenic and aciduric organisms, tipping the balance of the 'demin-remin' cycle towards net mineral loss and hence caries. In addition, the consumption of acidic drinks in today's societies has removed the protective nature of the biofilm, leading to erosion. Erosion and caries are 'modern-day' diseases and reflect an imbalance within the oral biofilm resulting in the demineralisation of teeth.

[The role of mechanical factors in the development of cervical wedge-shaped erosions]. / Rôle des facteurs mécaniques dans le développement des lacunes cunéiformes cervicales.

The surface of single or multiple cervical wedge-shaped defects was studied with a scanning electron microscope. After an initial stage during which the root surface became smooth and polished, the developed lesions had an angular shape with the presence of one or several grooves of 0.2 to 0.3 mm in width at the angle vertex. The presence of these grooves forming horizontal gutters strongly suggested the existence of a horizontal brushing movement. Beside these large grooves, a more or less parallel network of fine striae was observed. The lesion surfaces consisted of dentin with obliquely oriented tubules which were not completely sclerosed. Relatively thin bacterial layers were present on these surfaces. The presence of horizontal wear gutters seemed to confirm the traumatic origin of the wedge-shaped defects connected with toothbrushing.

Evaluation of bacteria-induced enamel demineralization using optical profilometry.

OBJECTIVES: Streptococcus mutans is considered a major causative of tooth decay due to its ability to rapidly metabolize carbohydrates such as sucrose. One prominent excreted end product of sucrose metabolism is lactic acid. Lactic acid causes a decrease in the pH of the oral environment with subsequent demineralization of the tooth enamel. Biologically relevant bacteria-induced enamel demineralization was studied. METHODS: Optical profiling was used to measure tooth enamel decay with vertical resolution under one nanometer and lateral features with optical resolution as a result of S. mutans biofilm exposure. Comparison measurements were made using AFM. RESULTS: After 72h of biofilm exposure the enamel displayed an 8-fold increase in the observed roughness average (R(a)), as calculated over the entire measured array. Similarly, the average root mean square (RMS) roughness, R(RMS), of the enamel before and after biofilm exposure for 3 days displayed a 7-fold increase. Further, the direct effect of chemically induced enamel demineralization using biologically relevant organic acids was shown. Optical profiles of the enamel surface after addition of a 30% lactic acid solution showed a significant alteration in the surface topography with a corresponding increase in respective surface roughness statistics. Similar measurements with 10% citric acid over seconds and minutes give insight into the demineralization process by providing quantitative measures for erosion rates: comparing surface height and roughness as metrics. SIGNIFICANCE: The strengths of optical profilometry as an analytical tool for understanding and analyzing biologically relevant processes such as biofilm induced tooth enamel demineralization were demonstrated.

Niveles de Streptococcus mutans y lactobacillus en saliva de pacinetes pediátricos con erosión dental: estudio piloto / Levels of Streptococcus mutans and lactobacillus in saliva of pediatric patients with dental erosion: a pilot study

La erosión dental asociada al consumo frecuente y poco moderado de bebidas carbonatadas y jugos de fruta comerciales es un cuadro común en la clínica odontopediátrica diaria. El propósito de este estudio fue estimar los niveles de Streptococcus mutans y de lacotbacillus en pacientes pediátricos con ersoión dental con el objeto de contribuir a una mejor comprensión del perfil microbiológico de los mismos. El estudio se llevó a cabo como un estudio caso-control no apareado. Se diseñó un grupo de estudio, pacientes con erosión (n=10) y dos grupos control: pacientes con caries (n=10) y pacientes libres de caries (n=10). Los niveles de los microorganismos mencionados se midieron a través de test microbiológicos comerciales de uso reconocido (CRT bacteria, Vivadent). Se determinó, además, el pH salival, índices CPOD y ceod e índice de placa O`Leary en los tres grupos de pacientes y se estableció la correlación entre variables entre los grupos. Los niveles de Streptococcus mutans resultaron similares en pacinetes con erosión y pacientes con caries y significativamente diferentes de aquellos observados en pacientes libres de caries (p<0.05), mientras que los niveles de Lactobacillus resultaron similares en pacientes con erosión y pacientes sin caries y significativamente diferentes de los registrados para pacientes con caries. Se concluye que los pacientes con erosión presentan un perfil salival y microbiológico similar al de los pacientes con caries. Sin embargo, se asemejan a los pacientes libres de caries en lo relativo al desarrollo de ellas. Ello podría explicarse a través de las diferencias de pH salival observadas que no favorecerían la metabolización de carbohidratos por parte del Streptococcus mutans