The determination of the lactate formation potential is possible in the form of a biochemical rapid test that provides information about the metabolic activity of caries-causing bacteria in the oral environment and thus about the caries risk of a patient. The development of caries is a multicausal process in which many factors are involved. And yet, caries cannot develop without the intervention of bacteria. These cariogenic bacteria have one crucial thing in common: their metabolism converts carbohydrates, including sugars, into lactic acid and other acids. These acids, in turn, lead to demineralization of the tooth (dissolving out mineral substances) and finally to cavitation (formation of a hole due to loss of substance). The higher the metabolic activity of the cariogenic (caries-causing) germs, the higher the release of lactate (lactic acid) in the patient’s mouth. This activity may well vary from patient to patient with the same clinical findings. It therefore makes sense to base the therapy measures and prophylaxis recommendations for the patient on the metabolic activity of the caries-causing bacteria. The caries risk test (Clinpro, Cario L-Pop) is a helpful and uncomplicated tool in the hands of dentists and dental professionals to orient dental therapy toward prevention (toward caries-preventive measures), to detect caries at an early stage, and to stop the carious process at an early stage.
Indications (areas of application)
The method is used to determine the metabolic activity of caries-causing bacteria in saliva on the basis of their lactic acid formation rate and thus, in conjunction with other clinical parameters, contributes to the determination of a patient’s individual caries risk. The test is used judiciously:
- As part of the initial assessment: to determine the current caries risk and to uncover hidden risks that remain concealed from the visual clinical findings.
- For follow-up of the caries process at recall (regular follow-up appointments).
- For patient motivation in the context of individual prophylaxis.
- To monitor the success of individual prophylaxis
Contraindications
The test result may be falsified by:
- The intake of drugs with antibacterial effect.
- By antibacterial lozenges.
- Through antibacterial mouth rinses.
Before the examination
Before the examination, the patient must consider the following points:
- Teeth must be brushed, with a minimum of 5 minutes but a maximum of 2 hours prior to brushing.
- After brushing must not eat or drink.
- Neither tooth-friendly nor sugary chewing gum may be chewed.
- For brushing, the usual toothpaste should be used, even if it contains bactericidal (germ-killing) additives such as chlorhexidine or triclosan.
The procedure
The test to determine lactate production potential is performed with lactic acid indicator sticks (Clinpro Cario L-Pop from 3M Espe). The instantaneous potential of cariogenic germs to produce lactic acid when sugar is added is measured. The sample is taken on the tongue, as the biofilm deposited on it is representative of the germs in saliva and plaque (dental plaque). Unlike the bacterial saliva tests for Streptococcus mutans and lactobacilli, the sample taken here does not need to be incubated: the test result can be read after just two minutes. The test strips are supplied in so-called blister packs. Each blister is divided into three compartments: two liquid reservoirs and a compartment containing the still dry test stick. The test stick itself contains sucrose (sugar). The two liquid reservoirs contain the enzyme lactate dehydrogenase and a color indicator, respectively. Principle of the test reaction taking place:
The amount of lactic acid formed within 2 minutes is visualized by coupling it to an enzymatic reaction with a color change:
- Sugar (test sticks) + cariogenic bacteria (tongue) → formation of lactic acid.
- Conversion of lactic acid with the help of the enzyme lactate dehydrogenase → blue-violet reaction product.
Procedure:
- The dry indicator rod is removed from the foil pouch.
- The rod is placed centrally on the outstretched tongue of the patient and turned back and forth 4 times under light pressure until it is soaked with saliva.
- The rod is carefully put back into its blister compartment without piercing the separating layer to the first liquid reservoir.
- The liquid at the outer blister end is now gently pushed towards the liquid in the middle compartment with thumb and forefinger.
- Both fluids are mixed and activated by pressing back and forth several times from one reservoir to the other.
- The outer blister section is now folded onto the middle one and held down to prevent backflow.
- The diagnostic liquid is now carefully (attention: splashing!) pressed further in the direction of the test stick.
- The test stick is rotated four times in the liquid, then left in it for 2 minutes.
The reading must be taken immediately after the expiration of the 2 minutes in daylight by comparison with the reference scale: The darker the discoloration, the higher the lactic acid formation rate or lactate formation potential and caries risk. The scale shows 9 color fields, which are compared with the color change of the test stick. In simplified terms, the comparison allows the following diagnostic conclusions to be made, with a more detailed interpretation of results provided by the manufacturer:
| Test stick has the color of the fields | Lactic acid formation rate | Current caries risk management | Progress checks |
| 1 to 3 | low | good | normal recall |
| 4 to 6 | Medium | moderate | closer recall |
| 7 to 9 | high | bad | intensive examination and treatment |
After the examination
A black-labeled control stick is included with the test to verify activation of the diagnostic fluid and is placed in its blister after reading the test stick. It must have turned blue-violet after a further two minutes.
Possible complications
- Diagnostic fluid may cause severe eye irritation and skin irritation and may also stain skin and clothing. Appropriate precautions should be taken.
- Allergic reactions can not be excluded.
