[An in-vivo bacteriological study on the effects of acid etching at the bottom of cavities]

The authors evaluate the effect of etching on the presence of bacterial colonies at the bottom of sockets.

For this purpose, 19 molars with first class carious lesions were selected belonging to patients age between 20 and 26 years old, referred for treatment at the outpatient clinics of the Dentistry Clinic. The teeth were due to undergo repair with amalgam using, as a foundation, fourth generation dentinal enamel adhesives. The clinical trial, which was performed in strict conditions of asepsis, included the preparation of Black's first class sockets at the bottom of which the author's looked for the mark of the "cri dentinaire". Samples were collected of dentin presenting these characteristics before and after etching treatment. The latter consisted in the application of 37% orthophosphoric acid to dentin for 10 seconds; this served to remove the smear layer. The samples obtained in this way were sent to the Institute of Microbiology and Virology to undergo culture tests.

The results obtained show that before etching 75% of the sample was positive for the presence of bacteria; this percentage fell to 53% of the sample after treatment.

The authors conclude that prepared sockets, even if ready for restoration, are in the majority of cases still septic and that the total etch technique is not capable of fully removing any bacteria present. Given that the effects of acid mordanting on dental tissues are well known, the authors recommended paying particular attention to dentinal disinfection before using an adhesive system that involves the removal of the smear layer.