title: Short dental implants (6 mm) versus long dental implants (11-15 mm) in combination with sinus floor elevation procedures: 3-year results from a multicentre, randomized, controlled clinical trial.
abstract: OBJECTIVE
  To test whether the use of short dental implants (6 mm) results in an implant survival rate similar to that with longer implants (11-15 mm) in combination with sinus grafting.
  
  
  METHODS
  This multicentre study enrolled 101 patients with partial edentulism in the posterior maxilla and a remaining bone height of 5-7 mm. Included patients were randomly assigned to receive short implants (6 mm; GS/group short) or long implants (11-15 mm) simultaneously with sinus grafting (GG/group graft). Six months after implant placement (IP), implants were loaded with single crowns (PR) and patients were re-examined yearly thereafter. Assessed outcomes included: implant survival, marginal bone level changes (MBL), probing pocket depth (PPD), bleeding on probing (BoP) and plaque accumulation (PCR) during 3 years of loading as well as recording of any adverse effects. In addition to descriptive statistics, statistical analysis has been performed for the two treatment modalities using a non-parametric approach.
  
  
  RESULTS
  In 101 patients, 137 implants were placed. At the 3-year follow-up (FU-3), 94 patients with 129 implants were re-examined. The implant survival rate was 100% in both groups. MBL at FU-3 was 0.45 mm (GG) and 0.44 mm (GS) (p > 0.05). A statistically significant loss of MBL was observed in both GG (-0.43 ± 0.58 mm) and GS (-0.44 ± 0.56 mm) from IP to FU-3, and from PR to FU-3 in GG (-0.25 ± 0.58 mm) but not in GS (-0.1 ± 0.54 mm). PCR and BoP at FU-3 did not show any difference between the groups but for PPD (p = 0.035).
  
  
  CONCLUSIONS
  Within the limitations of this study, implants with a length of 6 mm as well as longer implants in combination with a lateral sinus lift may be considered as a treatment option provided a residual ridge height of 5-7 mm in the atrophied posterior maxilla is present.
authors.affiliation: Academy for Oral Implantology, Private Hospital, Vienna, Austria.
authors.forename: Veronika
authors.identifier: http://orcid.org/0000-0002-3547-7541
authors.initials: V
authors.lastname: Pohl
authors.affiliation: Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.
authors.forename: Daniel S
authors.identifier: http://orcid.org/0000-0002-1764-7447
authors.initials: DS
authors.lastname: Thoma
authors.affiliation: Aesthetic Dent, Private Practice, Szczecin, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Sporniak-Tutak
authors.affiliation: University of Santiago de Compostela, Santiago de Compostela, Spain.
authors.forename: Abel
authors.initials: A
authors.lastname: Garcia-Garcia
authors.affiliation: Division of Prosthodontics, School of Dental Medicine, University of Connecticut, Farmington, CT, USA.
authors.forename: Thomas D
authors.initials: TD
authors.lastname: Taylor
authors.affiliation: Academy for Oral Implantology, Private Hospital, Vienna, Austria.
authors.forename: Robert
authors.initials: R
authors.lastname: Haas
authors.affiliation: Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.
authors.forename: Christoph H F
authors.initials: CH
authors.lastname: Hämmerle
mesh_terms: D015921:Dental Implants; D017267:Dental Prosthesis Design; D005500:Follow-Up Studies; D006801:Humans; D011475:Prosthesis Failure; D059546:Sinus Floor Augmentation / Q000379:methods*; D013997:Time Factors
chemical_list: D015921:Dental Implants
keywords: dental implant; multicentre; posterior maxilla; randomized controlled clinical trial; short dental implant; single unit; sinus floor elevation; sinus grafting