title: Effect of different implant placement depths on crestal bone levels and soft tissue behavior: a randomized clinical trial.
abstract: OBJECTIVE
  This randomized clinical trial analyzed crestal bone changes and soft tissue dimensions surrounding implants with an internal tapered connection placed in the mandible anterior region at different depths (equicrestal and subcrestal).
  
  
  METHODS
  Eleven edentulous patients (five implants per patient) were randomly divided in a split-mouth design: G1, 28 equicrestal implants; and G2, 27 subcrestal implants. All implants were immediately loaded. Correlation between keratinized tissue width (KTW) and vertical mucosa thickness (MT) with soft tissue recession was analyzed. Intraoral radiographs were used to evaluate crestal bone changes. Patients were assessed immediately, 4-, and 8-months after implant placement. Rank-based ANOVA-type statistical test was used for comparison between groups (α = 0.05).
  
  
  RESULTS
  Fifty-five implants (G1 = 28 and G2 = 27) were assessed in 11 patients. Implant survival rate was 100% for both groups. Both tested implant placement depths presented similar crestal bone loss (P > 0.05). Significant crestal bone loss for each group was found in the different measurement times (T4 and T8) (P < 0.05). Implant placement depths, KTW, and vertical MT had no effect on soft tissue recession (P > 0.05).
  
  
  CONCLUSIONS
  Different implant placement depths do not influence crestal bone changes. Soft tissue behavior is not influenced by different implant placement depths or by the amount of keratinized tissue.
authors.affiliation: Department of Prosthodontics, Faculdade Integrada de Pernambuco, Recife, Pernambuco, Brazil.
authors.forename: Rafael Amorim Cavalcanti
authors.initials: RAC
authors.lastname: de Siqueira
authors.affiliation: Department of Radiology, Latin American Institute for Dental Research and Education (ILAPEO), Curitiba, Paraná, Brazil.
authors.forename: Flávia Noemy Gasparini Kiatake
authors.initials: FNGK
authors.lastname: Fontão
authors.affiliation: Department of Prosthodontics, Latin American Institute for Dental Research and Education (ILAPEO), Curitiba, Paraná, Brazil.
authors.forename: Ivete Aparecida de Mattias
authors.initials: IAM
authors.lastname: Sartori
authors.affiliation: Private Practitioner, Recife, Pernambuco, Brazil.
authors.forename: Paulo Gustavo Freitas
authors.initials: PGF
authors.lastname: Santos
authors.affiliation: Department of Prosthodontics, Latin American Institute for Dental Research and Education (ILAPEO), Curitiba, Paraná, Brazil.
authors.forename: Sérgio Rocha
authors.initials: SR
authors.lastname: Bernardes
authors.affiliation: Department of Restorative Dentistry, School of Dentistry, State University of Londrina, Londrina, Paraná, Brazil.
authors.forename: Rodrigo
authors.identifier: http://orcid.org/0000-0001-5781-9760
authors.initials: R
authors.lastname: Tiossi
mesh_terms: D000368:Aged; D000539:Alveolar Process / Q000033:anatomy & histology*; D000069343:Bone-Implant Interface / Q000502:physiology*; D003758:Dental Implantation, Endosseous / Q000379:methods*; D005881:Gingiva / Q000502:physiology*; D006801:Humans; D008875:Middle Aged
keywords: bone remodeling; cone-beam computed tomography; immediate dental implant loading