Objectives: The implant abutments, which had their own colour, might cause the discoloration of peri-implant mucosa. We aimed to appraise trails comparing the discoloration of peri-implant soft tissue around zirconia and titanium or golden abutments, the tints of which were vastly different.
Data: We included randomized controlled trials (RCTs), controlled clinical trials (CCTs), cohort studies with patients rehabilitated with zirconia, titanium or golden implant abutments, quantitatively comparing the discoloration of peri-implant soft tissue according to CIE-Lab colour scale.
Sources: A systematic search was conducted in PubMed, EMBASE, CDSR, and CENTRAL databases without any restriction on September 23, 2017. "Grey" literatures were also searched. A manual search was carried out as well.
Study selection: Of 584 articles initially retrieved, eight were eligible for inclusion. After data extraction, meta-analyses with mean differences (MDs) and their 95% confidence intervals (CIs) were employed. Moreover, the risk of bias within or across studies was assessed by Cochrane Collaboration's tool for assessing risk, the Newcastle-Ottawa scale, funnel plots, or Egger's test.
Results: Four RCTs and four cohort studies were included. Soft-tissue discoloration around zirconia abutments was significantly less likely compared to that around titanium abutments (MD = -1.84; 95% CI = -3.62 to -0.07; P = 0.04 < 0.05) or golden abutments (MD = -0.90; 95% CI = -1.60 to -0.20; P = 0.01 < 0.05).
Conclusions: Zirconia abutments with white tint compared to grey titanium or golden abutments seem to restore a more appropriate colour match between peri-implant mucosa and natural teeth.
Clinical significance: Based on the present evidence, the "nature-like" zirconia abutments should be applied more often in the clinic.
Prospero registration number: CRD42017075930.
Keywords: Aesthetics; Gingival colour; Implant abutments; Meta-analysis; Peri-implant soft tissue; Zirconia.
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