Dentinal permeability of the dog canine after exposure of a cervical cavity to the beam of a CO2 laser.

The dentinal permeability of the axial wall of a class V cavities in the canine of the dog was analyzed before and after its laser CO2 irradiation at two energy levels: 285 J per cm2 and 570 J per cm2. The sealing of the exposed dentin was verified by means of a pellet of cotton wool placed in contact with the axial wall and on which 20 microliters of a 50 mg per ml solution of noradrenaline was injected with a micrometric syringe. The transdentinal passage of noradrenaline induces a vasoconstriction of the pulp which is attested by a drop in its blood pressure. The absence of any variation in the pulpal pressure is an indication of the sealing to noradrenaline of the dentinal wall irradiated with an energy level of 570 J per cm2. This experimentation illustrates that it is possible to obtain dentinal sealing by means of laser irradiation without affecting the underlying pulp. The quality of this reduction in permeability is dependent upon the different factors which define the energy level.