title: Retention of sealants during orthodontic treatment: an in vitro comparison of two etching protocols.
abstract: OBJECTIVE
  To test the retention of smooth-surface sealants bonded with different etching protocols against toothbrushing and, secondarily, to characterize the type and location of sealant loss.
  
  
  METHODS
  Eighty-nine extracted human teeth were randomly assigned one of two etching protocols: 37% phosphoric acid etch (ETCH) or self-etching primer (SEP). Six specimens at a time were placed in a toothbrushing machine to simulate 4, 8, 12, and 24 months of toothbrush abrasion. Using black-light photographs of each specimen taken before and after brushing, four blinded coinvestigators determined new sealant loss, loss along the edge of an initial defect, and the location of sealant loss.
  
  
  RESULTS
  Overall, there were significantly (P < .05) more teeth with sealant loss in the SEP group (38.6%) than in the ETCH group (15.5%). New loss of sealant was significantly (P < .05) more likely in the SEP group (27.2%) than in the ETCH group (2.2%). Of the teeth with new loss of sealant, all (100%) had loss at the edge, and 23% had progressive loss. There was no significant group difference in sealant loss from initial defects. Of the teeth that showed enlargement of initial defects, 91% had loss at the edge and 91% had progressive loss.
  
  
  CONCLUSIONS
  Using SEP to apply facial sealants results in lower retention rates than using ETCH. The vast majority of sealant loss occurs at the edges. Loss of sealant due to enlargement of an initial defect is highly progressive over time.
authors.affiliation: a  Private Practice, Temecula, Calif.
authors.forename: Christopher
authors.initials: C
authors.lastname: Chau
authors.affiliation: b  Associate Professor and Chairman, Department of Orthodontics, Texas A&M University Baylor College of Dentistry, Dallas, Tex.
authors.forename: Phillip M
authors.initials: PM
authors.lastname: Campbell
authors.affiliation: c  AEGD Resident, Texas A&M University Baylor College of Dentistry, Dallas, Tex.
authors.forename: Nima
authors.initials: N
authors.lastname: Deljavan
authors.affiliation: d  Associate Professor, Department of Orthodontics, Texas A&M University Baylor College of Dentistry, Dallas, Tex.
authors.forename: Reginald W
authors.initials: RW
authors.lastname: Taylor
authors.affiliation: e  Regents Professor and Director of Orthodontic Research, Department of Orthodontics, Texas A&M University Baylor College of Dentistry, Dallas, Tex.
authors.forename: Peter H
authors.initials: PH
authors.lastname: Buschang
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D006801:Humans; D009970:Orthodontics / Q000379:methods*
keywords: 37% Phosphoric acid; Etching; Sealant loss; Sealant retention; Self-etching primer