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Theme 8: The cariogenic situation in oral cavity. Methodology of indication and elimination. The composition and properties of saliva. Structure and biological properties of enamel.

The educational material.

Dental caries (tooth decay) is an infectious, communicable disease resulting in destruction of tooth structure by acid-forming bacteria found in dental plaque, an intraoral biofilm, in the presence of sugar. The infection results in loss of tooth minerals that begins on the outer surface of the tooth and can progress through the dentin to the pulp, ultimately compromising the vitality of the tooth.

Dental caries is a multifactorial disease process, often represented by the three interlocking circles and an arrow depicting the passage of time.

It is well known that certain individuals develop much more caries than others, means have different caries risk and caries activity.

Risk is defined as the probability that a harmful (or unwanted) event will occur.

Caries risk assessment is the estimation of the probability of developing a new dental caries lesion within a specific timeframe, and also the estimation of the probability of a change in the size or activity of existing lesions in the mouth.

Dental caries is a multifactorial disease and, therefore, its related factors should be addressed when developing a caries risk assessment tool. These factors can be clustered in :

• microbiologic,

• clinical,

• behavioral,

• environmental,

• social variables.

For caries development, caries risk factors must occur simultaneously:

The caries-risk assessment is performed in order to introduce causal measures before irreversible lesions have become established, while the caries activity test is carried out in order to decide and monitor correct and efficient treatment of a patient.

Detachment of risk factors and of risk indicators (risk markers).is important for the clinician. A risk factor plays an essential role in the etiology and occurrence of the disease, while a risk indicator is a factor or circumstance that is indirectly associated with the disease.

Risk factors are the life-style and biochemical determinants to which the tooth is directly exposed and which contribute to the development or progression of the lesion (plaque, saliva, diet, etc.).

Risk indicators are socioeconomic factors (socially deprived, low education level, poor economy, self-esteem), factors related to general health (diseases, handicap), and epidemiologic factors (living in a high-caries area or country, high past-caries experience).

Some researchers divide all caries risk factors on General and Local

General risk factors are: - general condition of organism, environmental factors (contens of fluor in a water), type of nutrition, bad habits and behavioral habits,

Local risk factors are: Composition and properties of mouth liquid, structure of hard tissues of tooth, level of their mineralization, spectrum and titre of microflora of oral cavity, consumption of refined carbohydrates, crowding, high intensity of caries prevalence and incidence

The general risk factors can influence on realization of local factors.

Specific diet, drinking water with low level of fluoride and calcium, pathological condition of organs of human body can change composition and properties of dental plague, enamel and saliva.

For the individual, the identification of factors responsible for caries risk and caries activity should form the basis for targeted action against the etiological factors involved. Knowledge of risk factors gives the patient an opportunity to reflect over his or her situation and an option to take a personal responsibility for the future oral health. For an appropriate assessment of caries activity, facts from the case history, clinical and radiographic examinations, dietary history, and supplementary laboratory tests must be taken into account.

An individual approach has been suggested and described by Bratthall and Tynelius-Bratthall. According to their method, biochemical and demographic parameters should be combined with a clinical judgment ("gut feeling") of the dental professional to elicit proper results. First, determine which particular factors are involved. Next, find out why these factors are present. Finally, try to change the situation by targeted actions against identified factors. For caries-risk assessment of the individual should be estimate covering background data (case history), clinical examination, and caries activity tests. The background factors that directly or indirectly can be of importance for the disease usually belong to one or more of the following groups:  General diseases  Medication  Social/family situation  Dietary habits/feeding  Oral-hygiene routines, fluoride support When interviewing the patient for the case history, questions should be asked to clarify these points. There are few general diseases that directly affect the teeth, although there are several that indirectly influence the carious process. In fact, and especially regarding children, being ill with medication in combination with anxious and sometimes overprotective parents constitutes a greater caries risk than the disease itself. Several drugs contain a high content of fermentable carbohydrates and have a low pH. Furthermore, the depressing influence on saliva secretion exerted by various medicines is a well-documented risk. A troubled family or social situation might be reflected by factors such as stress (decreased saliva secretion), lack of interest in hygiene (poor plaque control), and low income (cariogenic diet). The diet clearly affects the teeth in a direct (in the form of erosion) and indirect (through tooth formation, saliva secretion, and bacterial activity) way. In developing a risk profile, the diet should always be considered. An interview or a "3-day record" of all food and snack intakes are common methods used to obtain information about the diet of a patient. Clinical Examination for Evaluation of Caries Activity The past caries prevalence is always important, but one is not necessarily at risk in spite of 30 previous fillings. It is very useful to try to look "behind" the recorded decayed, missing, or filled primary or permanent teeth (dmft/DMFT) values.

First, one should consider if there are more or fewer fillings or extractions than considered normal for a particular age group. The patients should then be asked questions such as "Why and when were the teeth extracted (caries, periodontal disease, orthodontics), or were the restorations placed long ago or recently?" Check the number, extension, and appearance of the lesions, cavities, and fillings. The texture and localization of lesions might provide important hints for caries activity. For example, presence of early enamel lesions ("white spots") on newly erupted teeth indicates an active demineralization process. The evaluation will provide the examiner with information on the extent of the problem and if caries seems to be a past or present problem. In the next step, local aggravating factors such as crowded arches, deep fissures, imperfect fillings and exposed root surfaces are evaluated. The morphology of the enamel must always be checked. Although the present evidence supporting an inherited susceptibility to dental caries is limited, altered enamel development, such as increased porosity and decreased mineral content are directly linked to an increased caries risk. Finally, the estimation of the oral hygiene standard with a disclosing solution can be recommended. It should be emphasized that visible plaque on the labial surfaces of maxillary incisors of a young child is a serious sign of caries risk.