Although some dental diseases are the result of genetic factors, others, such as caries, are caused by local environmental factors. Compared to other parts of the body, the oral cavity harbors the most diverse microbiota and provides the microbial communities living and growing on all exposed oral surfaces such as enamel, exposed cementum, and dentin, as well as sulcular epithelium a safe, wet and warm environment where nutrition is provided through saliva, gingival fluids and the host’s diet. In a healthy neutral oral PH, the resident bacteria help to develop the host’s immune system, keep invading pathogens to low level, and assist in regulating the cardiovascular system and digestive tract, while living in a symbiotic state. However a slight shift in PH levels from alkaline to acidic allows for an over saturation of resident pathogens that produce metabolic acids and can thrive in an acidic environment which diffuse through the hard tissue (enamel and dentin) protective pellicle and initiate demineralization process that at a high frequency occurrences leads to active caries lesion formation. The acidic episodes when salivary PH falls to the critical level of 5.5 or lower, are directly correlated with the consumption of fermentable carbohydrates, the frequency with which those sugars are consumed, and their bioavailability to the bacteria for metabolism. Dental erosion as the most prominent factor contributing to dental wear, can be defined as the dissolution of the hard tissues (enamel and dentin) due to oral acids, without the involvement of acidogenic bacteria. When erosion in noticeable, it can be assumed the hard tissue structure has already been initially damaged, yielding a softer enamel or dentin surface. At this point, the mechanical/physical action of tooth brushing increases tooth erosion and abrasion as well as removal of the protective acquired pellicle thus directly exposing enamel and dentin to oral acids. Therefore it is important to select a tooth paste with a low RDA (Relative dentin abrasiveness) to minimize abrasion of previously eroded surfaces. Sodium bicarbonate tooth pastes which typically have RDAs below 80 (due to very low hardness of sodium bicarbonate itself) or household baking soda with RDA of 7, are excellent choice for patients who aggressively brush their teeth, have signs of erosion from diet or gastroesophagal reflux disease (GERD) or have a moderate to high caries risk as well as patients with periodontitis. The fluoride ions found in today’s toothpastes remineralize enamel and increase its ability to resist further demineralization and erosion. Another factor that plays an essential role in maintaining the neutral PH (6.0 to 7.5) through buffering acids and cleansing of the hard and soft tissue, is normal salivary flow. Additionally, the calcium and phosphate ions that are naturally found in saliva are key factors in the development, progression and prevention of dental caries and periodontal disease.
This article was extracted from a self-study CE coarse titled: “managing oral PH through diet and therapeutic agents can help fight dental diseases and support remineralization and oral health” written by Martha McComas, RDH, MS published in September 2019 issue of “The Journal of Multidisciplinary Care Decisions in Dentistry”