Effect of Etchant on Sealant Retention: An In Vitro Study

Objective: To test the null hypothesis of no differences in the retention of a highly filled sealant placed using either self-etching primer (SEP) or phosphoric acid etchant (PAE). 

Method: A total of 89 teeth were stratified (32 incisors; 12 canines; 45 premolars) and randomly assigned to two experimental groups; one group was sealed following preparation with self-etching primer (N=44); the other group was sealed following preparation with 37% phosphoric acid (N=45).  The crowns were mounted in acrylic rings and a standardized area of exposed enamel was covered with sealant.  One investigator covered the exposed areas with etchant and sealed all of the teeth using OpalSeal (Ultradent).  Orthodontic brackets were placed and light cured. The teeth were then placed in a tooth-brushing simulator and brushed 15,000 strokes, for the real-time equivalent of 24 months.  Standardized photographs were taken under black light conditions prior to brushing, and after 4, 8, 12, and 24 months of simulated brushing. Evaluations were performed by four blinded judges.  

Result: Of the 89 teeth, 13 (14.6%) showed slight loss of sealant.  Losses were significantly (p<.05) greater for the SEP (92.3%) than the PAE (7.7%) groups. Most losses occurred at the edges of the sealant; 23% of the losses became progressively larger over time. Approximately 12.4% of the teeth had small initial defects on the edges of the sealant that enlarged over time. Thinning of sealant was observed in 37% of the teeth; it occurred predominately at the edges of the sealant and was progressive (85%). Neither thinning or defects showed significant differences between the SEP and PAE groups. 

Conclusion: The etchant used to place sealants had an effect on sealant loss; thinning occurred and defects increased in size regardless of the etchant used to place the sealant. This research was partially funded by the Baylor Oral Health Foundation.