Gum recession at the neck of the tooth leads to exposed dentin (tooth bone), which is crisscrossed with microscopic tubules (tubules). Through their connection to the pulp (to the tooth nerve), pain stimuli are triggered to cold, air, sweet or sour. The prerequisite for hypersensitive necks of teeth is therefore first of all a recession of the gingiva (the gums). This results in partial (partial) exposure of the tooth root, which is not covered with the pain-insensitive enamel cap. The dental hard tissue of the root consists of dentin (tooth bone) and is only covered by a very thin layer of root cementum, which, once exposed, is very quickly lost through natural abrasion during chewing and tooth brushing. The dentin itself is crisscrossed by innumerable very fine dentin tubules. These are filled with dentin liquor (tissue fluid) and sensitive processes of the pulp (the tooth nerve). According to Brännström’s hydrodynamic theory of pain, lead:
- Thermal stimuli, especially cold,
- Pressure,
- Suction,
- Drying out (e.g., in the course of bleaching) or
- Osmotic stimuli (e.g., from concentrated acidic or sugary solutions).
to a rapid flow of dentin liquor in the tubules. This fluid flow, in turn, causes irritation of the pain receptors of the pulp: a short, stabbing pain is the result. Now, exposed dentin is not necessarily sensitive to pain. The prerequisite for this is that many dentinal tubules with a large canal diameter are exposed, so that their fluid space is in contact with the oral environment.
Indications (areas of application)
A sealant for exposed dentin (synonym: dentin abrasion protection) can protect the underlying tooth structure (exposed tooth necks) from exposure to external stimuli such as heat or cold.
Contraindications
- The use of desensitizing preparations is prohibited in cases of proven allergy or hypersensitivity to one of the ingredients, e.g. methacrylates.
- Pain reactions originating from exposed dentinal tubules should not be confused with pulpitis-related pain (pain due to inflammation of the dental pulp). Desensitizing varnishes are not indicated in the presence of pulpitis.
- Desensitizing preparations are not suitable for direct capping (covering the exposed pulp, for example, in deep caries with opening of the nerve).
The procedure for the treatment of sensitive necks of teeth usually has two objectives:
I. Inhibition of the pain response of the pulp: usually with potassium salts that increase the threshold for the transmission of the pain stimulus, eg.
- Potassium chloride, e.g., in Sensodyne –toothpaste or- mouthwash.
- Potassium nitrate, e.g. in Sensodyne Multicare toothpaste or blend-a-med Pro-Sensitiv toothpaste.
II. mechanical closure of the dentinal tubules: by applying methacrylate-containing (synthetic resin) varnishes, precipitation of protein-containing structures or poorly soluble salts, eg:
- Methacrylate-based sealant protection, e.g. Seal & Protect: thin-flowing synthetic resin penetrates the openings of the tubules.
- Glutaraldehyde-containing solutions, e.g. Gluma Desensitizer Power Gel: protein structures in the dentin liquor are precipitated and block the tubules.
- Desensitization with VivaSens: First, the dentinal tubules are blocked by forming a transparent varnish film (made of hydroxypropyl cellulose). Organic acids (phosphonic acid methacrylate) and alcohol (ethanol/ethanol) precipitate proteins (protein compounds) contained in the dentin fluid. In addition, sparingly soluble calcium and other salts are formed (in the presence of phosphonic acid methacrylate and methacrylate-modified polyacrylic acid).
- Elmex Sensitive Professional toothpaste: the closure of the tubules is achieved by precipitation of the amino acid arginine and sparingly soluble calcium carbonate.
- Fluoridation with high-dose varnishes and gels, e.g. Duraphat, Bifluorid 12 or Elmex Gelée: the applied fluoride concentrate reacts with mineral components of the dentin to form a sparingly soluble calcium fluoride top layer.
The procedures
Toothpastes and mouth rinses with potassium salts are to be used in home dental care, just like Elmex Sensitive Professional toothpaste and Elmex jelly.For desensitizing varnishes used in dental practice, the procedure may differ from preparation to preparation. Here, the procedure must be followed according to the respective instructions for use:
- Clean the exposed tooth neck e.g. with polishing paste.
- Relative drying
- Drying of the dentin, but not overdrying
- Applying the sealing varnish
- Reaction time according to the instructions for use
- Blowing off the excess solvent
- If necessary, light curing of paints based on methacrylate
- If necessary, application of another coat of varnish
- For methacrylate lacquers after light curing: removal of the oxygen inhibition layer (superficial synthetic resin layer, which can not cure due to air contact) by polishing.
After the procedure
For exposed sensitive necks of teeth is recommended:
- The use of a toothbrush that tends to be soft
- The use of a toothpaste against hypersensitive dentin and
- The switch to a toothbrushing technique that is appropriate for the findings.
