title: Strength comparison of four techniques to secure implant attachment housings to complete dentures.
abstract: BACKGROUND
  Implant overdentures become thinner and weaker after direct transfer of implant attachment housings. While much has been published on denture repair, these data do not directly apply to implant overdentures because the introduction of a metal housing changes the character of the repair. It is desirable to make a strong repair to avoid prosthesis fracture.
  
  
  OBJECTIVE
  The purpose of this study was to compare the flexural strengths of 4 different methods for chairside direct transfer of implant attachment housings.
  
  
  METHODS
  Eighty 11.5 × 9.1 × 39 mm heat-polymerized acrylic resin blocks were processed, assessed for porosities, and polished. An 8.5 mm diameter hole was drilled to a depth of 5 mm in the center of each block. Attachment housings were set into the bases with 4 different repair materials: autopolymerized acrylic resin (APAR), light-polymerized acrylic resin (LPAR), autopolymerized acrylic resin with silanated attachment housings (APSAH), and light-polymerized acrylic resin with silanated attachment housings (LPSAH). Blocks were immersed in water for 30 days in an incubator. A 3-point bend test was done in a universal testing machine, and load to fracture was recorded (MPa). Results were compared with 2-way ANOVA (α=.05).
  
  
  RESULTS
  APSAH had the highest mean flexural strength at fracture (863.1 ±87 MPa) as compared to APAR (678.4 ±72.4 MPa), LPAR (550.9 ±119.3 MPa), and LPSAH (543.2 ±100.8 MPa). A comparison among the 4 groups showed that there were significant differences in maximum flexural strength (P<.001). The mean maximum strength of autopolymerized acrylic resin groups was significantly higher than light-polymerized acrylic resin groups. Silanation increased strength significantly compared to nonsilanated groups.
  
  
  CONCLUSIONS
  The flexural strength of autopolymerized acrylic resin with silanated attachment housings was significantly higher than autopolymerized acrylic resin alone, light-polymerized acrylic resin alone, or light-polymerized acrylic resin with silanated attachment housings. Autopolymerized acrylic resin produced stronger constructs than light-polymerized materials.
authors.affiliation: Department of Prosthodontics, University of Alabama at Birmingham School of Dentistry, Birmingham, Ala., USA.
authors.forename: Karla B
authors.initials: KB
authors.lastname: Domingo
authors.forename: John O
authors.initials: JO
authors.lastname: Burgess
authors.forename: Mark S
authors.initials: MS
authors.lastname: Litaker
authors.forename: Michael S
authors.initials: MS
authors.lastname: McCracken
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D000497:Alloys; D003722:Dental Alloys / Q000737:chemistry; D015921:Dental Implants; D003764:Dental Materials / Q000737:chemistry; D019094:Dental Prosthesis, Implant-Supported; D003799:Dental Stress Analysis / Q000295:instrumentation; D003819:Denture Bases; D003779:Denture Design; D003781:Denture Retention / Q000295:instrumentation*; D003824:Denture, Complete; D003828:Denture, Overlay; D006801:Humans; D055115:Light-Curing of Dental Adhesives; D008422:Materials Testing; D018583:Pliability; D058105:Polymerization; D019904:Polymethyl Methacrylate / Q000737:chemistry; D012821:Silanes / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013997:Time Factors; D014025:Titanium / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D000180:Acrylic Resins; D000497:Alloys; D003722:Dental Alloys; D015921:Dental Implants; D003764:Dental Materials; D012821:Silanes; D014867:Water; C060386:Triad resin; C031462:titanium alloy (TiAl6V4); D019904:Polymethyl Methacrylate; D014025:Titanium