title: Does thread design influence relative bone-to-implant contact rate of palatal implants?
abstract: OBJECTIVE
  To determine histologically whether (a) changing the thread design between first- and second-generation palatal implants (Straumann, Basel, Switzerland) influences the bone-to-implant contact (BIC) rate of palatal implants subjected to conventional loading, and (b) whether histological evidence of peri-implantitis appears in this setting.
  
  
  METHODS
  Patients who had received an orthodontic palatal implant for skeletal anchorage between January 1998 and December 2007 were examined. First-generation palatal implants (Straumann, Basel, Switzerland) 3.3 mm in diameter and 6 mm or 4 mm long were used, as were second-generation implants 4.1 mm in diameter and 4.2 mm long. After completion of active orthodontic treatment, the implants were removed and prepared for histological investigation. This study was designed as a comparative analysis of a series of two cases: 28 explanted first-generation (n = 14) and second-generation (n = 14) palatal implants were analyzed.
  
  
  RESULTS
  Bone healing was achieved with all implants. Both types of implants revealed a mean bone-to-implant contact (BIC) rate that was nearly equal: 80.7% (SD 10.7%) for the first-generation and 81% (SD 13.1%) for the second-generation implants. Bone resorption was only observed in 5 palatal implants (3/14 of the first, and 2/14 of the second generation).
  
  
  CONCLUSIONS
  Despite differing thread designs, second-generation palatal implants revealed similar bone-to-implant contact rates as did those of the first generation. Few patients presented bone resorption in the peri-implant bone.
authors: Department of Orthodontics, University Hospital Mainz, Augustusplatz 2, 55131 Mainz, Germany. brjung@uni-mainz.de
authors: Britta A
authors: BA
authors: Jung
authors: Martin
authors: M
authors: Kunkel
authors: Peter
authors: P
authors: Göllner
authors: Thomas
authors: T
authors: Liechti
authors: Maximilian
authors: M
authors: Moergel
authors: Robert
authors: R
authors: Noelken
authors: Peter
authors: P
authors: Borbély
authors: Heinrich
authors: H
authors: Wehrbein
mesh_terms: D000293:Adolescent; D000328:Adult; D001863:Bone Screws; D002648:Child; D017267:Dental Prosthesis Design; D019544:Equipment Failure Analysis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010158:Palatal Obturators; D010159:Palate / Q000473:pathology* / Q000601:surgery*; D055815:Young Adult