T oward the end of the 19th century, the new science of bacteriology arose as a result of major advances in the formulation of growth media and the development of techniques for isolating and studying bacteria. Micro-organisms proved to be major causes of several diseases that were fatal to humans.Disease occurred when a specific micro-organism reached a target site where the tissues and conditions enabled the organism to flourish and reach the elevated numbers needed to cause significant damage to the host and even death. W.D. Miller (1890) learned these isolation techniques and applied them to the examination of the many micro-organisms resident within the oral cavity. At the same time, he found that, collec - C ONTROVERSYResearch on dental caries has a long history, and the biology of its development has proved to be far more complex than anyone might have thought. Specificity and non-specificity of the causative bacteria have been at the center of the controversy of how this disease occurs and how it should be treated. From this article, it appears that the composition, metabolism, and caries-causing capability of applicable bacterial mixtures are integrated, and that they are affected collectively by oral ecological conditions and changes. This is an area of Oral Biology that needs further exploration and could provide significant dividends in the development of our understanding of human ecological infections in general.- ABSTRACT: For more than 100 years, investigators have tried to identify the bacteria responsible for dental caries formation and to determine whether their role is one of specificity. Frequent association of Lactobacillus acidophilus and Streptococcus mutans with caries activity gave credence to their being specific cariogens. However, dental caries occurrence in their absence, and the presence of other bacteria able to produce substantial amounts of acid from fermentable carbohydrate, provided arguments for non-specificity. In the 1940s, Stephan found that the mixed bacteria in dental plaque produced a rapid drop in pH following a sugar rinse and a slow pH return toward baseline. This response became a cornerstone of plaque and mixed-bacterial involvement in dental caries causation when Stephan showed that the pH decrease was inversely and clearly related to caries activity. Detailed examination of the pH (acidbase) metabolisms of oral pure cultures, dental plaque, and salivary sediment identified the main bacteria and metabolic processes responsible for the pH metabolism of dental plaque. It was discovered that this metabolism in different individuals, in plaque in different dentition locations within individuals, and in individuals of different levels of caries activity could be described in terms of a relatively small number of acid-base metabolic processes. This led to an overall bacterial metabolic vector concept for dental plaque, and helped unravel the bacterial involvement in the degradation of the carbohydrate and nitrogenous substrates that produce the acids and alkali that aff...

Temporomandibular Disorder (TMD) is a term generally applied to a condition or conditions characterized by pain and/or dysfunction of the masticatory apparatus. Its characterization has been difficult because of the large number of symptoms and signs attributed to this disorder and to variation in the number and types manifested in any particular patient. For this study, data on 4,528 patients, presenting over a period of 25 years to a single examiner for TMD treatment, was made available for retrospective analysis and determination of whether the TMD care-seeking patient can be profiled, particularly pain difficulties. All patients in this database filled out a questionnaire and were examined for the prevalence of a range of symptoms and clinical examination findings (signs) commonly attributed to TMD. There was no attempt in this study to assign patients to TMD diagnostic subcategories. The data collected were analyzed to determine which of these symptoms and signs were sufficiently "characteristic of the TMD condition" that they might be used in diagnosis, research and treatment, especially in patients needing relief from pain and discomfort. All 4,528 patients reported symptoms and all but 190 of them also showed signs upon examination. Symptoms most commonly reported on the questionnaire included (i) pain (96.1%), (ii) headache (79.3%), (iii) temporomandibular joint discomfort or dysfunction (75.0%) and (iv) ear discomfort or dysfunction (82.4%). In the 4,338 patients who showed signs, the most prevalent was tenderness to palpation of the pterygoid muscles (85.1%), followed by tenderness to palpation of the temporomandibular joints (62.4%). Pain symptoms and signs were often accompanied by compromised mandibular movements, TMJ sounds and dental changes, such as incisal edge wear and excessive overbite. Clearly prevalence of pain disclosed by the symptoms and signs examinations was high. Patients showed variable prevalence and nonprevalence of eight categories of painful symptoms and seven categories of painful signs. Despite the variability, these might be developed in the future into TMD scores or indices for studying and unraveling the TMD conundrum.

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