Roles of Salivary Components in Streptococcus mutans Colonization in a New Animal Model Using NOD/SCID.e2f1−/− Mice

Streptococcus mutans plays an important role in biofilm formation on the tooth surface and is the primary causative agent of dental caries. The binding of S. mutans to the salivary pellicle is of considerable etiologic significance and is important in biofilm development. Recently, we produced NOD/SCID.e2f1−/− mice that show hyposalivation, lower salivary antibody, and an extended life span compared to the parent strain: NOD.e2f1−/−. In this study we used NOD/SCID.e2f1−/− 4 or 6 mice to determine the roles of several salivary components in S. mutans colonization in vivo. S. mutans colonization in NOD/SCID.e2f1−/− mice was significantly increased when mice were pre-treated with human saliva or commercial salivary components. Interestingly, pre-treatment with secretory IgA (sIgA) at physiological concentrations promoted significant colonization of S. mutans compared with sIgA at higher concentrations, or with human saliva or other components. Our data suggest the principal effects of specific sIgA on S. mutans occur during S. mutans colonization, where the appropriate concentration of specific sIgA may serve as an anti-microbial agent, agglutinin, or an adherence receptor to surface antigens. Further, specific sIgA supported biofilm formation when the mice were supplied 1% sucrose water and a non-sucrose diet. The data suggests that there are multiple effects exerted by sIgA in S. mutans colonization, with synergistic effects evident under the condition of sIgA and limited nutrients on colonization in NOD/SCID.e2f1−/− mice. This is a new animal model that can be used to assess prevention methods for dental biofilm-dependent diseases such as dental caries

Microbial-associated oral lichenoid reactions

OBJECTIVE: The objective of the present study was to compare a new type of symptomatic lichenoid reaction, specifically located on the mucosal side of the lips, and associated with microorganisms, with a matched group presenting with reticular oral lichen planus (OLP) of the buccal mucosa. PATIENTS AND METHODS: The mean age for both groups was 66 years with a predominance of women (62%). The lichenoid reaction group (n = 25) presented with a reticular reaction pattern embracing various degrees of erythema. Patients presenting with OLP had similar lesions confined to the buccal mucosa but not on the mucosal side of the lips. RESULTS: In both groups, 80% were on any type of medication. However, 56% of the patients with lichenoid reactions medicated with more than three drugs compared with 29% (P < 0.05) in the OLP group. The former group more often used medicaments prescribed for cardiovascular diseases (48%vs 25%). Twenty-two of the patients with lichenoid reactions were treated with chlorhexidine. In 80% of these patients (n = 18), the lesions improved or completely healed, indicating a microbial association. CONCLUSION: Lichenoid reactions present on the mucosal side of the lips may be initiated by microbial plaque precipitated on the buccal surfaces of the anterior teeth

Oral bacteria and clinical variables in dependent individuals at a special facility*

The oral health of dependent residents at special facilities has often been reported as being poor, but it is difficult to relate oral health to general health and define the need for oral health care. Microbiological analyses of the oral flora have been suggested as a suitable method for evaluating oral health in this group of patients. A study was performed at a nursing facility where 33 individuals participated. The aim was to describe their oral flora in relation to other health variables and to classify the residents on different risk levels. An oral examination of the residents was made at the facility, together with a 3-day food record and an oral microbiological analysis. The analysis classified the residents in different categories according to both acid-producing bacteria and the flora correlated with a reduction in general health. The categories were based on previous studies conducted at the Department of Microbiology (Faculty of Odontology in Göteborg). The present study revealed that the level for acid-producing bacteria was high in 12 individuals and the micriobial level according to decreased general health was high in seven individuals. A high level of acid-producing bacteria was related to functional impairment, which was in turn related to nutritional problems and help with oral hygiene. The microbial level according to the reduction in general health did not significantly correlate with other variables

Evaluation of salivary flow in patients during head and neck radiotherapy Análise do fluxo salivar em pacientes durante a radioterapia em cabeça e pescoço

Radiotherapy is frequently employed for the treatment of head and neck squamous cell carcinoma. Among the side effects, xerostomia is one of the most important. With the objective of evaluating the role of radiotherapy in salivary flow, we performed three salivary sample collections: at the beginning of, during, and immediately after radiotherapy. The results showed that the salivary flow values of the first collection were very similar to those of the control group. However, during treatment, there was a significant decrease of the salivary flow (p = 0.0008), which continued low immediately after radiotherapy (p = 0.0009). Our study showed that radiotherapy leads to an important reduction of salivary flow during and after radiotherapy.<br>A radioterapia é um tratamento comumente empregado em pacientes portadores de carcinomas espinocelulares em cabeça e pescoço. Entre os efeitos colaterais locais, a xerostomia é um dos mais importantes. Com o objetivo de avaliar o efeito da radioterapia sobre o fluxo salivar, foram feitas 3 coletas salivares: no início, em um período intermediário e posteriormente ao tratamento radioterápico. Os resultados obtidos demonstraram médias de fluxo salivar semelhantes entre a coleta inicial e o grupo controle. Com o decorrer da radioterapia, houve diminuição significativa do fluxo salivar na coleta intermediária (p = 0,0008), que se manteve após o término da radioterapia (p = 0,0009). Nosso estudo enfatiza que há redução significativa do fluxo salivar durante e após a radioterapia