Introduction
Medicatio cavi dentis, the second principle of caries treatment, is the treatment of the prepared cavity with medicaments after preparatio (first principle) and before obturatio (third principle). It deals with what preparation leaves behind – debris, bacteria and open dentinal tubules – and protects the pulp, whose response decides whether the tooth stays vital and free of pain under the filling.
Definition and goals
The Latin term means "medication of the tooth cavity": medicatio – treatment with a medicament; cavum dentis (genitive cavi dentis) – the cavity of the tooth, here the prepared cavity. Its target is the pulp–dentin complex: dentin and pulp react as one unit, because every cut tubule leads to an odontoblast.
Medicatio cavi dentis is the cleaning, disinfection and protection of the prepared cavity with agents chosen by its depth, so that neither residual bacteria, the filling material nor the procedure itself harms the pulp.
- Cleaning (toilet of the cavity): washing out dentin chips, debris, blood and saliva.
- Disinfection: killing bacteria left on the walls and in the tubules after excavation.
- Protection of the pulp from chemical, thermal and bacterial irritation by sealing the tubules.
- Stimulation of the pulp (odontotropic effect): inducing tertiary (reparative) dentin and tubular sclerosis.
- Desensitising: stopping fluid movement in open tubules, the cause of postoperative sensitivity (hydrodynamic theory).
An ideal cavity medicament is antibacterial, non-irritating to the pulp and non-staining, and does not interfere with the setting or bonding of the filling material.