Monographs in Oral Science最新文献

The World Health Organization has defined probiotics as "Live microorganisms which, when administered in adequate amounts, confer a health benefit to the host." Traditionally, probiotic microorganisms (mainly Lactobacillus ssp. and Bifidobacterium ssp.) have been used to prevent or treat diseases in the gastrointestinal tract. In the past 20 years, there has been an increased interest in possible oral health effects of probiotics. In vitro studies have shown promising results with growth inhibition of mutans streptococci (MS) and Candida albicans. There are only a few clinical studies with caries development as the primary outcome while more studies have been focusing on control of caries risk factors or so-called surrogate outcomes. Several studies have evaluated the effects of probiotic bacteria on MS in saliva and/or plaque, and a number of probiotic strains show ability to reduce the number of MS. Probiotic bacteria have not been shown to permanently colonize the oral cavity; in early-in-life interventions or in subjects with a mature microbiota. To date investigated strains are transiently present in saliva during and shortly after an intervention. There are eight randomized controlled clinical trials with dental caries as outcome and probiotic strains, administration, duration of the intervention, and target group varied. In a majority of the studies (75%), the interventions resulted in caries reduction in the treatment groups. Although a majority of these studies suggest a caries-preventive effect of probiotic bacteria, more long-term clinical studies are needed in this field before probiotics could be recommended for preventing or treating dental caries.

The advent of the "genomic era" has allowed for nutrigenomics studies to be carried out, which aim to reveal whether there are interactions between the food we consume and our genetic make-up. In turn this information will provide the scientific basis for improved public health messages related to nutrition and diet. With the availability of high throughput, inexpensive and sometime "bed-side" technology, studies into the effect of diet on the aetiology of common oral diseases and oral conditions could now be easily carried out. It is becoming more and more convincing that interactions between genotype and diet are important in determining the risk of most if not all common complex diseases, and it is therefore highly probable that these interactions will be important in determining oral disease risk. A large body of data relating to nutritional genetic studies where the outcome measures have been markers of disease risk, provide proof of principle and highlight the importance of understanding these interactions, illustrating the potential impact dietary modification could have on oral health. These are areas of growth that need to be investigated further.

Microelements are essential components of the diet. This chapter describes the effect of several such elements: zinc, copper, iron, tin, and iodine, on oral health. As part of normal diets, these elements have limited associations with specific oral conditions. This is partly because of their presence at relatively low concentrations and partly because they are most often present as mixtures where the effect of any one element is confounded by others. Deficiencies in microelements can cause health problems. Hence supplements, often containing one or more microelements, are prescribed to combat such conditions. All these ions exhibit antibacterial properties. Such effects are invariably small at the concentrations found in conventional foods and drinks. However, at higher concentrations, these ions can inhibit acid production by plaque bacteria involved in dental caries. Of more importance, zinc and tin have potentially significant effects on the de- and remineralisation processes involved in dental caries. Indeed, both elements have been included in oral hygiene products such as toothpastes for many years. Zinc, in particular, has demonstrated not only the ability to reduce dissolution rates of enamel and hydroxyapatite but also to inhibit calculus formation. Tin can also markedly reduce the dissolution rates. Both Cu and Fe have demonstrated anti-caries effects in animal models, whilst Fe-containing drinks have been shown to reduce enamel erosion in situ. The broad spectrum antibacterial properties of iodine have been promoted for its potential use against both early childhood caries and chronic periodontitis. However, more convincing clinical research is required to validate efficacy.

Sugar is added to food for a multitude of functions: fermentation, preservation, physical and chemical, and also to satisfy the consumer's preference for sweetness. Unfortunately, sugar consumption is also a main aetiological factor for dental caries. The relationship between sugar and caries was established in the latter half of the 19th century. Many factors influence this relationship: the availability of sugar for bacterial digestion, the presence of acidogenic bacteria in the plaque on teeth, and the ability of fluoride and saliva to counteract bacteria and acids. The importance of the frequency of administering sugars over the amount has been demonstrated in various studies in humans. Through guidelines, world and national health organizations advocate the reduction of sugar consumption to below 10E% (daily dietary energy percentage consumption per capita), but voluntary implementation on an individual basis is difficult for many, and maybe more compulsory strategies that aim to reduce both the amount and frequency of sugar intake are needed.

Due to the increasing focus on host inflammatory processes with regard to the aetiology of periodontal disease, diet has become an important factor in host modulation. Recent investigations showed that the industrialized western diet, which is characterized by highly processed foods (processed carbohydrates like sugar, white flour, and processed fatty acids like trans fats) and a low micronutrient density, promotes gingival and periodontal inflammation. On the other hand, a plant-based diet rich in low-glycaemic, complex carbohydrates (like in fruits, vegetables, legumes), Omega-3 fatty acids, micronutrients (like vitamins, minerals), phytochemicals, plant nitrates, and fibres seems to bring benefits as well for periodontal inflammation as for caries, and general health. This chapter aims to present the underlying studies and possible mechanisms.

Ultratrace element is a relatively new term, and is defined as those elements with an established, estimated, or suspected dietary requirement of minute amount, generally of the order of µg/day. This chapter focuses on fluorine (F), aluminium (Al), molybdenum (Mo), and cobalt (Co). Whilst diet is the principal source of Al, Mo, and Co found in the body, inadvertent ingestion of dental hygiene products accounts for a significant proportion of F intake. Apart from F, the influence of other ultratrace elements on oral health, and in particular dental caries, has not been fully established. The calcified tissues contain 99% of body F. During tooth development, ingested (systemic) F is incorporated into the apatite crystals of the developing tooth which helps in improving resistance to acid demineralisation. However, the presence of low but constant levels of topical F in the fluid phase at the tooth enamel surface are more important in controlling tooth decay in people of all ages. An adequate intake, from all dietary and non-dietary sources, is estimated as 0.05 mg/kg body weight/day for children older than 6 months and adults, based on estimated intakes that have been shown to reduce the incidence of dental caries while minimising adverse health effects such as dental fluorosis. An inverse relationship between incidence of dental caries and levels of Al in drinking water, food, and soils has been indicated by some epidemiological studies. Co and Mo, whilst occasionally showing potential beneficial oral health effects in laboratory experiments, do so at concentrations much higher than found in vivo.

The foods in the diet contain a wide range of organic and inorganic compounds. Considering these from an elemental perspective, 5 so-called macroelements, calcium, potassium, sodium, phosphorus and chlorine, are contained in comparatively large quantities in foods compared to all other elements. This chapter attempts to review the importance of these dietary macroelements on oral health, and in particular their role in tooth loss, dental caries, erosive tooth wear and periodontal disease. Calcium and phosphate make up the bulk of the mineralized human tissues. Adequate intake of both is therefore of crucial importance in maintaining the health, function and retention of teeth and bones. Supplementation of the diet with calcium has also been shown to aid in maintaining and improving oral health. Several attempts have been made to lessen the erosive potential of beverages through calcium supplementation. Adequate calcium intake is also crucial for maintaining periodontal health. In many areas, however, the evidence is still emerging or controversial. Phosphate supplementation of the diet was once thought to decrease caries incidence, although studies in children were not successful. Furthermore, little attention has been paid to the other macroelements, highlighting the need for more well-controlled and comprehensive studies.

Diet and nutrition are fundamental in maintaining the general and oral health of populations. Diet refers to the total amount of food consumed by individuals; whereas nutrition is the process of utilising food for growth, metabolism and repair of tissues. The relationship between diet and nutrition and health is 2-way; health status can be affected by nutrient deficiency and vice versa. Dietary guidelines have been developed to provide evidence-based food and beverage recommendations for populations; aiming to promote a diet that meets the nutrient requirement, and to prevent diet-related diseases such as dental caries and obesity. Based on the amount required by the human body for normal metabolism, growth and physical well-being, nutrients are divided into 2 categories: macronutrients consisting of proteins, carbohydrates and fat; and micronutrients consisting of vitamins and minerals. Fats are the most energy-dense macronutrient; whereas carbohydrates are quantitatively the most important dietary energy source for most populations. Proteins are vital structural and functional components within every cell of the body and are essential for growth and repair and maintenance of health. Vitamins and minerals, which are found in small amounts in most foods, are essential for normal metabolic function. This chapter provides an overview of the impact of nutrients on general and oral health, with an emphasis on macronutrients.