title: Is a grooved collar implant design superior to a machined design regarding bone level alteration? An observational pilot study.
abstract: OBJECTIVE
  This retrospective observational pilot study examined differences in peri-implant bone level changes (ΔIBL) between two similar implant types differing only in the surface texture of the neck. The hypothesis tested was that ΔIBL would be greater with machined-neck implants than with groovedneck implants.
  
  
  METHODS
  40 patients were enrolled; n = 20 implants with machined (group 1) and n = 20 implants with a rough, grooved neck (group 2), all placed in the posterior mandible. Radiographs were obtained after loading (at 3 to 9 months) and at 12 to 18 months after implant insertion. Case number calculation with respect to ΔIBL was conducted. Groups were compared using a Brunner-Langer model, the Mann-Whitney test, the Wilcoxon signed rank test, and linear model analysis.
  
  
  RESULTS
  After the 12- to 18-month observation period, mean ΔIBL was -1.11 ± 0.92 mm in group 1 and -1.25 ± 1.23 mm in group 2. ΔIBL depended significantly on time (P < .001), but not on group. In both groups, mean marginal ΔIBL was significantly less than -1.5 mm. Only insertion depth had a significant influence on the amount of periimplant bone loss (P = .013). Case number estimate testing for a difference between group 1 and 2 with a power of 90% revealed a sample size per group of 1,032 subjects.
  
  
  CONCLUSIONS
  ΔIBL values indicated that both implant designs fulfilled implant success criteria, and the modification of implant neck texture had no significant influence on ΔIBL.
authors.forename: Renzo
authors.initials: R
authors.lastname: Bassetti
authors.forename: Regula
authors.initials: R
authors.lastname: Kaufmann
authors.forename: Andreas
authors.initials: A
authors.lastname: Ebinger
authors.forename: Regina
authors.initials: R
authors.lastname: Mericske-Stern
authors.forename: Norbert
authors.initials: N
authors.lastname: Enkling
mesh_terms: D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging*; D015921:Dental Implants; D017267:Dental Prosthesis Design; D005260:Female; D006801:Humans; D008297:Male; D008334:Mandible; D010865:Pilot Projects; D011859:Radiography; D012189:Retrospective Studies; D013499:Surface Properties
chemical_list: D015921:Dental Implants