title: Peri-implant soft-tissue health surrounding cement- and screw-retained implant restorations: a multi-center, 3-year prospective study.
abstract: OBJECTIVE
  The purpose of this prospective clinical study was to evaluate peri-implant soft-tissue conditions and esthetic fulfillment during a 3-year follow-up period following prosthetic rehabilitation.
  
  
  METHODS
  As part of a prospective multi-center study, 152 ITI dental implants were placed in 80 patients in the maxillary anterior region. Fifty-nine crowns (38.82%) were cement retained, while 93 (61.18%) crowns were screw retained. At loading and 3, 6, 12 and 36 months post-loading, modified plaque index (MPI), sulcus bleeding index (SBI), keratinized mucosa (KM), gingival level (GL), and esthetic fulfillment were recorded.
  
  
  RESULTS
  All patients completed the study and no complications were reported. While statistically not significant at all time points, cement-retained crowns seemed to present a worsening trend in MPI and SBI scores. Interestingly, screw-retained crowns seemed to present an opposite picture, their MPI and SBI scores improved over time. While plaque accumulation, prophylaxis and depth of crown margin significantly affected levels of sulcus bleeding, prophylaxis alone played a key role in reducing plaque accumulation. No soft tissue recession was observed in either cement- or screw-retained crowns up to 3 years post-loading. Esthetic fulfillment survey revealed that patients did not have a preference for crown types; however, dentists favored cement-retained over screw-retained crowns.
  
  
  CONCLUSIONS
  Peri-implant soft tissues responded more favorably to screw-retained crowns when compared with cement-retained crowns. However, no soft-tissue recession was observed in either type of crowns. Cement-retained crowns were preferred by dentists, while patients were equally satisfied with either type of crowns they received.
authors.affiliation: Department of Restorative Dentistry and Biomaterial Science, Harvard School of Dental Medicine, Boston, MA 02115, USA. hpweber@hsdm.harvard.edu
authors.forename: Hans P
authors.initials: HP
authors.lastname: Weber
authors.forename: David M
authors.initials: DM
authors.lastname: Kim
authors.forename: Mavis W
authors.initials: MW
authors.lastname: Ng
authors.forename: Jae W
authors.initials: JW
authors.lastname: Hwang
authors.forename: Joseph P
authors.initials: JP
authors.lastname: Fiorellini
mesh_terms: D003442:Crowns; D003758:Dental Implantation, Endosseous; D015921:Dental Implants; D018772:Dental Marginal Adaptation; D003773:Dental Plaque; D017268:Dental Prosthesis Retention / Q000379:methods*; D004812:Epidemiologic Methods; D006304:Health Status; D006801:Humans; D009909:Oral Health; D016474:Weight-Bearing
chemical_list: D015921:Dental Implants