Caries is a very common oral disease, which seriously endangers people’s physical and mental health. The occurrence of carious disease is the result of many factors together. When food enters the mouth, the sugars in it are used by the bacteria in the mouth to produce many kinds of organic acids, which invade the tooth tissue and cause tooth demineralization, thus producing caries.
In the 1960s, Keyes proposed the theory of “triad of factors” of caries: 1.
1.Bacteria: Streptococcus deformans, Lactobacillus and Actinomyces
Bacteria can cause caries only by forming dental plaque
2.Food: sugar provides energy for bacteria, and a lot of experiments prove that sugar is significantly caries-causing
Cariogenicity: sucrose>glucose>maltose>lactose>fructose>sorbitol>xylitol
3.Host: crowded or misaligned teeth, between two teeth
Tooth structure (deep sockets, etc.)
Physicochemical properties of teeth: composition and degree of mineralization such as underdeveloped enamel
High carbonate content in the hard tissues of teeth prone to demineralization
The external environment such as the secretion of saliva, the change of composition, the size of buffering capacity and the change of antibacterial system are closely related to the occurrence of caries.
4.Time: 70s, “quadruple factor”
History of fluoride.
Fluorine is one of the 14 essential trace elements and one of the constituents of human body. Fluorine is present in various tissues of the human body in different concentrations.
1, blood, breast milk and soft tissues
2, Bone and teeth 99% of fluorine is deposited in calcified tissues
3. Saliva and plaque
Fluorine is also widely present in nature in many forms, including drinking water, soil, atmosphere, and in plants and animals. The human body takes in fluoride in many ways
1.Drinking water 65%
2.Things 25%
Fluoride prevents caries because it has the following effects:
1.Fluorine can directly inhibit the energy metabolism needed for the growth of bacteria in the mouth, inhibit the adhesion of bacteria to the tooth surface, inhibit the activity of many enzymes in the process of bacterial metabolism, so that bacterial growth and metabolism are disrupted or stopped.
2.Fluorine combines with hydroxyapatite in the tooth enamel structure, reducing the solubility of the enamel surface and enhancing the resistance to acid.
3.Fluorine can also promote the adhesion of calcium and phosphorus in saliva on the surface of teeth, which helps the continued maturation of enamel after tooth eruption, the recovery of destroyed apatite in caries lesion site, and the remineralization of caries damage.
4.Higher concentration of fluoride has the effect of killing cariogenic bacteria and other bacteria.
Adequate amount of fluoride can prevent tooth decay. However, excessive fluoride intake can cause acute or chronic fluorosis.
The adult lethal dose of sodium fluoride is 5-10g (2.2 vs. 4.4gF). The average lethal dose is 4-5g. 15mg/kg for children can be lethal. The lethal dose for infants is 0.25g (250mg).
The most likely toxic dose (near true toxic dose) of PTD is used as an indication to receive emergency treatment. The fluorine intake for possible poisoning is 5mg/kg.
1.<5mg/kg Take certain amount of calcium, aluminum and magnesium as antidote
2.=>5mg/kg Use first aid measures, then hospitalization for observation
3.=>15mg/kg Use emergency measures, including first aid treatment cardiac monitoring and anti-shock therapy in the emergency room.
Excess fluorine damage to the organism.
1. Fluorine salt contact with moist skin and mucous membranes form fluorohydrogen acid, causing chemical burns
2, as a systemic protoplasmic poison inhibits enzyme activity
3 . Binding with calcium required for nerve activity
4. Causes hyperkalemia triggering cardiotoxicity
Acute poisoning mainly manifests as: dizziness, headache, weakness, nausea, vomiting, diarrhea, even intestinal bleeding, imbalance of blood calcium balance, muscle cramps, deficiency, dyspnea, cyanosis, etc. In severe cases, it can cause organic damage to the heart, liver and kidney, and even coma. Excessive intake of fluorine can lead to death within 4 hours.
Treatment principles: vomiting, gastric lavage, oral or intravenous calcium, sugar and fluid supplementation, and symptomatic treatment. One of the simplest and easiest on-the-spot resuscitation measures is to quickly give the patient a large amount of milk so that the calcium in the milk can partially bind with the fluorine, thus reducing the toxic effect of fluorine on the organism.
Chronic poisoning: dental fluorosis or bone fluorosis. As well as non-bone phase damage to the nervous system, skeletal muscle and kidneys.
Bone fluorosis: bone softening and ossification of parabasal soft tissues.
Dental fluorosis: dental fluorosis or enamel fluorosis, a specific type of enamel hypoplasia caused by excessive fluoride intake by the body during the period of tooth mineralization. It occurs mostly in permanent teeth and is rare in milk teeth. dean WHO recommends category 6.
The use of fluoride includes both topical and systemic applications.
The main systemic applications are.
1. Fluoridation of water source Drinking water fluoride concentration in 0.7-1mg/L
<0.5mg/L Fluorosis index <0.6 Caries of 15 years old children are >1DMFT
The effect mainly shows the reduction of caries and the slowing down of caries progress. WHO 1958 recommends
2.Fluoridation of school drinking water, fluoridation of family drinking water
3.Salt fluoridation
4.Oral fluoride (fluorine tablet 0.25mg and 0.5mg fluorine solution, tea drinking, etc.)
5.Milk fluoridation 1986y
6.Fluorine drops: for children under 2 years old at bedtime Buccal mucosa or tongue, without drinking water, the incidence is reduced by 40% Systemic and local effects
Topical application can get certain caries prevention effect no matter in low fluorine area or in moderate fluorine area
The ways are
1.Fluoride toothpaste 1g/time adult
2.Sodium monofluorophosphate (non-staining, ph close to neutral and stable)
4.Stannous fluoride (easy hydrolysis, staining, short validity, metallic taste. (Improved anti-plaque, gingivitis, while anti-caries)
5.Sodium fluoride (“ion” type fluoride, release fluoride ion in water, no staining, ph neutral, stable)
6.Amine fluoride (organic fluoride. Typical surfactant, increase the fluorine uptake and deposition of tooth enamel, enhance the acid resistance of enamel and promote the remineralization of early caries damage, low toxicity
7.Fluorine water rinse (for moderate or high caries-prone areas: patients with high caries activity or susceptible patients, patients wearing fixed appliances during orthodontic period, disabled people who cannot self-care. Method: 0.2% NaF(900mgF ion/kg)/week 0.05% NaF(230mgF ion/kg)/day 5-6y 5ml/time >6y 10ml/time. Contain rinse for one minute and then spit out, half an hour without eating or rinsing, <5 years old, not recommended
8.Floss with fluoride
9, fluoride foam (APF 1.23% PH3-4 ,1/4 dosage) now with 0.6% usage, four minutes.
APF adult poisoning dose of about 250mg NaF,1-12y children for the adult dose of 1/13-1/2.
250mg NaF (0.11gF) for children (8.5-55mgF), fluorinated foam (APF 1.23%): at 0.69-4.47g
APF 0.6%:at 1.42-9.17g. now use 0.4-0.6g (instructions, 1-2min)
V. Fluorine-containing solution coating, fluorine-containing gel (APF 1.23%)
In short, the use of fluoride should adhere to the following principles.
1, Xing fluoride, in addition to fluorine damage.
2.Safety first, effect second.
3, the right amount.
4, integrated application.
Strictly grasp the boundaries of professional application and self-application. Long-term persistent use to be effective.