title: Single implants with different neck designs in the aesthetic zone: a randomized clinical trial.
abstract: OBJECTIVE
  To compare single implants in the aesthetic zone with different neck designs for marginal bone-level changes and clinical outcome measures.
  
  
  METHODS
  Ninety-three patients with a missing anterior tooth in the maxilla were randomly assigned to be treated with an implant with a 1.5 mm smooth neck ("smooth group"), a moderately rough neck with grooves ("rough group") or a scalloped moderately rough neck with grooves ("scalloped-group"). Implants were installed in healed sites and were loaded after 3 months. Follow-up visits were conducted at 6 and 18 months after implant placement.
  
  
  RESULTS
  The scalloped group showed significantly more radiographic bone loss from implant placement to 18 months (2.01 ± 0.77 mm) compared with the smooth group (1.19 ± 0.82 mm) and rough group (0.9 ± 0.57 mm). Furthermore the scalloped group showed significantly deeper pocket depths and a higher bleeding score. There were no between-group differences in soft tissue levels. Survival rates were 97% for the smooth group and 100% for the rough and scalloped groups (P>0.05). No significant differences in outcome were found between the smooth group and rough group.
  
  
  CONCLUSIONS
  For anterior tooth replacements, implants with a scalloped neck showed more marginal bone loss and less favourable clinical outcome compared with implants with a 1.5 mm smooth neck or implants with a rough neck.
authors: Department of Oral and Maxillofacial Surgery, University Medical Center Groningen and University of Groningen, Groningen, The Netherlands. l.den.hartog@kchir.umcg.nl
authors: Laurens
authors: L
authors: den Hartog
authors: Henny J A
authors: HJ
authors: Meijer
authors: Boudewijn
authors: B
authors: Stegenga
authors: Nynke
authors: N
authors: Tymstra
authors: Arjan
authors: A
authors: Vissink
authors: Gerry M
authors: GM
authors: Raghoebar
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016301:Alveolar Bone Loss / Q000145:classification; D003442:Crowns; D000044:Dental Abutments; D019250:Dental Implants, Single-Tooth; D003764:Dental Materials / Q000737:chemistry; D003774:Dental Plaque Index; D017267:Dental Prosthesis Design; D004955:Esthetics, Dental; D005260:Female; D005500:Follow-Up Studies; D005884:Gingival Hemorrhage / Q000145:classification; D006801:Humans; D008297:Male; D008437:Maxilla / Q000601:surgery; D008875:Middle Aged; D010512:Periodontal Index; D010514:Periodontal Pocket / Q000145:classification; D011446:Prospective Studies; D013499:Surface Properties; D016019:Survival Analysis; D014025:Titanium / Q000737:chemistry; D016896:Treatment Outcome; D055815:Young Adult; D015040:Zirconium / Q000737:chemistry
chemical_list: D003764:Dental Materials; D015040:Zirconium; D014025:Titanium; C028541:zirconium oxide