PubMed Health⌕ Search

Biomedical subjects

W Carstensen

Publications and source records attributed to W Carstensen.

7 recordsLinked to original sources
PubMed1995

Effect of reduction of phosphoric acid concentration on the shear bond strength of brackets.

The purpose of this study was to evaluate in vitro the effect of the reduction of phosphoric acid concentration on the shear bond strength of brackets to enamel. Twelve pairs of contralateral maxillary premolars were randomly divided into group 1 and group 2. Twelve additional upper premolars formed group 3. The three acid concentrations examined were 37% in group 1, 2% in group 2, and 5% in group 3. The buccal surfaces of the teeth were etched for 30 seconds, and metal brackets were bonded were Concise adhesive (3M Dental Products, St. Paul, Minn.). After storage of teeth in water at 37 degrees C for 1 week, a shear force was applied to the occlusal bracket wings in a direction parallel to the bracket base. The results showed that the mean shear bond strength after etching with 37% acid (x = 18.30 MPa) was significantly higher than that after etching with 2% acid (x = 15.28 MPa). The mean bond strength after etching with 5% acid (x = 16.49 MPa) was not significantly different from that after the use of the two other acids. The assessment of the Adhesive Remnant Index (ARI) showed that the amount of adhesive left on the teeth after debonding was smaller after etching with 2% acid than after etching with 37% acid or 5% acid. It was concluded that 2% phosphoric acid solution is appropriate for bonding of brackets. The reduced etching could be favorable in preventing enamel damage during the treatment and at the time of debonding.

Acid Etching, Dental↗
PubMed1993

Clinical effects of reduction of acid concentration on direct bonding of brackets.

A total of 600 metal mesh-backed brackets were directly bonded to the anterior teeth of randomly selected orthodontic patients. Prior to bonding, enamel etching was carried out with 37% phosphoric acid on one side and with 2% phosphoric acid on the other side. The etch duration was 30 seconds. After 1 year no statistically significant difference was found between the failure rates of the two etching procedures. The assessment of the Adhesive Remnant Index (ARI) after debonding, however, revealed that the application of 37% acid resulted in significantly higher amounts of residual adhesive left on the teeth. The present study demonstrates that a phosphoric acid concentration of 2% can be sufficient for bracket bonding on anterior teeth.

Adhesives↗
PubMed1992

The effects of different phosphoric acid concentrations on surface enamel.

The purpose of this study was to evaluate the effects of different acid concentrations on the enamel surface morphology. The buccal surfaces of 25 extracted premolars from young patients were etched with 40%, 20%, 10%, 5%, and 2% phosphoric acid solutions for 60 seconds. The specimens were examined with a scanning electron microscope in the occlusal, central, and cervical regions. A great variation of the etching patterns was observed in almost all test groups. The extent of the appearance of prism outlines was smaller in the cervical region and at lower acid concentrations. The advantages and disadvantages of the use of lower concentrated acids are discussed.

Acid Etching, Dental↗
PubMed1986

Clinical results after direct bonding of brackets using shorter etching times.

In the first part of the study, the clinical results after the direct bonding of 1,134 metal mesh-backed brackets have been evaluated. The etching of enamel was carried out with a solution of 37% phosphoric acid for 30-35 seconds. The rates of loosened brackets during the treatment period were for the upper and lower anterior teeth, 1.89% and 0.66%, respectively. In the second part, a comparison was made between the effects of 15-20 seconds and 30-35 seconds of etching on the clinical failure rate of the brackets. The number of failures within 9 months was also acceptable after the shorter etching time. A 15-second etching appears to be sufficient for the bracket bonding of anterior teeth.

Acid Etching, Dental↗