title: Peri-implant soft tissue colour around titanium and zirconia abutments: a prospective randomized controlled clinical study.
abstract: OBJECTIVE
  To objectively determine the difference in colour between the peri-implant soft tissue at titanium and zirconia abutments.
  
  
  METHODS
  Eleven patients, each with two contralaterally inserted osteointegrated dental implants, were included in this study. The implants were restored either with titanium abutments and porcelain-fused-to-metal crowns, or with zirconia abutments and ceramic crowns. Prior and after crown cementation, multi-spectral images of the peri-implant soft tissues and the gingiva of the neighbouring teeth were taken with a colorimeter. The colour parameters L*, a*, b*, c* and the colour differences ΔE were calculated. Descriptive statistics, including non-parametric tests and correlation coefficients, were used for statistical analyses of the data.
  
  
  RESULTS
  Compared to the gingiva of the neighbouring teeth, the peri-implant soft tissue around titanium and zirconia (test group), showed distinguishable ΔE both before and after crown cementation. Colour differences around titanium were statistically significant different (P = 0.01) only at 1 mm prior to crown cementation compared to zirconia. Compared to the gingiva of the neighbouring teeth, statistically significant (P < 0.01) differences were found for all colour parameter, either before or after crown cementation for both abutments; more significant differences were registered for titanium abutments. Tissue thickness correlated positively with c*-values for titanium at 1 mm and 2 mm from the gingival margin.
  
  
  CONCLUSIONS
  Within their limits, the present data indicate that: (i) The peri-implant soft tissue around titanium and zirconia showed colour differences when compared to the soft tissue around natural teeth, and (ii) the peri-implant soft tissue around zirconia demonstrated a better colour match to the soft tissue at natural teeth than titanium.
authors: Department of Periodontology, Philipps University Marburg, Marburg, Germany; Department of Prosthodontics, University Iuliu Hatieganu, Cluj-Napoca, Romania; Department of Periodontology, Dental School, University of Bern, Bern, Switzerland.
authors: Raluca
authors: R
authors: Cosgarea
authors: Cristina
authors: C
authors: Gasparik
authors: Diana
authors: D
authors: Dudea
authors: Bogdan
authors: B
authors: Culic
authors: Bettina
authors: B
authors: Dannewitz
authors: Anton
authors: A
authors: Sculean
mesh_terms: D000328:Adult; D003116:Color; D000044:Dental Abutments; D003758:Dental Implantation, Endosseous; D015921:Dental Implants; D017267:Dental Prosthesis Design; D005260:Female; D005881:Gingiva; D006801:Humans; D008297:Male; D014025:Titanium; D015040:Zirconium
chemical_list: D015921:Dental Implants; D015040:Zirconium; D014025:Titanium; C028541:zirconium oxide
keywords: implant abutments; mucosa colour; peri-implant soft tissue; titanium; zirconia