Immunohistochemical assessment of the peri-implant soft tissues around different abutment materials : an experimental study in human

Abstract

Objective To evaluate the effect of 4 different types of abutment material, which are titanium, zirconium oxide, gold alloy, and zirconia-coping cemented on titanium-base, on the surrounding soft tissues. Material and Methods Twenty dental implants in posterior edentulous area were randomly divided into 4 groups and inserted 4 types of abutment materials; Titanium, zirconia, gold-alloy, and titanium-base, on the implant installation surgery day. Eight weeks after implant surgery, peri-implant soft tissues around experimental abutments were harvested and split according to implant side; buccal, lingual, mesial, and distal. The specimens were processed through immunohistochemical preparation and stained with CD3, CD20, CD68, CD138, and factorVIII to identify T-cells, B-cells, macrophages, plasma cells, and microvessels, respectively. The quantitative assessment of cell markers was performed by one pathologist. The total counts of positive cell for one compartment were expressed as numbers of positive cells per square millimetre of soft tissues. The outcome was assessed immunohistochemical characteristic and microvessel density (MVD). Results Sixteen healthy patients, 6 males and 10 females, were included in this study. Total positive cells for titanium, zirconia, gold-alloy, and titanium-base, were 119.28, 177.06, 445.18, and 109, respectively. Factorial analysis of variance (factorial ANOVA) was used to analyse the data. Gold alloy group showed statistical significance higher number of positive cells, compared to titanium (p-value=0.009) and zirconia (p-value=0.042). Implant side exhibited no influence on positive cell number (p-value=0.825). Microvessel density was found no statistical difference between groups. Factorial AVOVA was performed and reported that no main effect was found in both abutment material (p-value=0.501) and implant side (p-value=0.910) to have influence on microvessel density. Conclusions Different types of abutment material had an influence on peri-implant soft tissues in immunohistochemical features. Gold alloy abutments exhibited more inflammatory cells in surrounding tissues than titanium and zirconia abutments. Different sides of implant showed no statistical difference in peri-implant tissues response in immunohistochemical aspect and microvessel density. The tissues around gold alloy abutment tended to experience a higher rate of inflammation-associated processes when compared to titanium and zirconia abutments.