title: Matrix metalloproteinases 2, 3, 8, 9, and 13 in the peri-implant soft tissues around titanium and zirconium oxide healing caps.
abstract: OBJECTIVE
  This human study sought to compare, from an immunohistochemical point of view, matrix metalloproteinases (MMPs) 2, 3, 8, 9, and 13 in the soft tissues around titanium and zirconium oxide healing caps.
  
  
  METHODS
  Five patients participated in this study. All patients received 3.8 × 11-mm dental implants, which were left to heal in a nonsubmerged (single-stage) mode. Healing caps (3.8 mm in diameter and 3.0 mm in height) were inserted in all implants. Half of the implants were randomly supplied with standard, prefabricated caps of commercially pure titanium (control), while the other half were randomly provided with zirconium oxide caps (test). After a 6-month healing period, gingival biopsy specimens were obtained with a circular scalpel around the healing caps of both groups, without unscrewing or removing the healing caps, and the samples underwent immunohistochemical processing for MMPs 2, 3, 8, 9, and 13.
  
  
  RESULTS
  Statistically significant differences were found in the values of MMP-8 in the cells of the inflammatory infiltrate, with higher values for the titanium samples. Statistically significantly higher values were found, also in the titanium samples, for MMP-9 in the endothelial cells of the blood vessels. No statistically significant differences were found for any other MMPs.
  
  
  CONCLUSIONS
  The present results showed that the soft tissues around titanium healing caps underwent a higher rate of restorative processes, most probably correlated to the MMP levels observed in the tissues.
authors.forename: Marco
authors.initials: M
authors.lastname: Degidi
authors.forename: Luciano
authors.initials: L
authors.lastname: Artese
authors.forename: Nicola
authors.initials: N
authors.lastname: Franceschini
authors.forename: Sara
authors.initials: S
authors.lastname: Sulpizio
authors.forename: Adriano
authors.initials: A
authors.lastname: Piattelli
authors.forename: Marcello
authors.initials: M
authors.lastname: Piccirilli
authors.forename: Vittoria
authors.initials: V
authors.lastname: Perrotti
authors.forename: Giovanna
authors.initials: G
authors.lastname: Iezzi
mesh_terms: D000328:Adult; D000368:Aged; D015921:Dental Implants; D004848:Epithelium / Q000201:enzymology; D005260:Female; D005881:Gingiva / Q000201:enzymology*; D006801:Humans; D008297:Male; D053509:Matrix Metalloproteinase 13 / Q000032:analysis; D020778:Matrix Metalloproteinase 2 / Q000032:analysis; D019278:Matrix Metalloproteinase 3 / Q000032:analysis; D020784:Matrix Metalloproteinase 8 / Q000032:analysis; D020780:Matrix Metalloproteinase 9 / Q000032:analysis; D020782:Matrix Metalloproteinases / Q000032:analysis*; D008875:Middle Aged; D014025:Titanium; D014945:Wound Healing; D015040:Zirconium
chemical_list: D015921:Dental Implants; D015040:Zirconium; D014025:Titanium; D053509:Matrix Metalloproteinase 13; D020782:Matrix Metalloproteinases; D019278:Matrix Metalloproteinase 3; D020778:Matrix Metalloproteinase 2; D020784:Matrix Metalloproteinase 8; D020780:Matrix Metalloproteinase 9; C028541:zirconium oxide