The impact of dis‐/reconnection of laser microgrooved and machined implant abutments on soft‐ and hard‐tissue healing

Objectives To (i) investigate the influence of different extensions of a laser microgrooved abutment zone on connective tissue attachment and (ii) assess the impact of a repeated abutment dis‐/reconnection on soft‐ and hard‐tissue healing. Materials and Methods Titanium implants were inserted epicrestally in the lower jaws of six dogs. Healing abutments with either partially ( LP ) or completely ( LC ) laser microgrooved margins or machined surface margins ( M ) were randomly allocated either to a single (1×)/repeated (2×) dis‐/reconnection at 4 and 6 weeks (test), respectively, or left undisturbed (control). At 6 and 8 weeks, histomorphometrical (e.g. most coronal level of bone in contact with the implant [ CBI ], subepithelial connective tissue attachment [ STC ]) and immunohistochemical ( C ollagen T ype‐ I [ CI ]) parameters were assessed. Results At control sites, LP / LC groups revealed lower mean CBL (8 weeks, 0.95 ± 0.51 vs. 0.54 ± 0.63 vs. 1.66 ± 1.26 mm), higher mean STC (8 weeks, 82.58 ± 24.32% vs. 96.37 ± 5.12% vs. 54.17 ± 8.09%), but comparable CI antigen reactivity. A repeated abutment manipulation was associated with increased mean CBL (8 weeks, 1.53 ± 1.09 vs. 0.94 ± 0.17 vs. 1.06 ± 0.34 mm), decreased STC (8 weeks, 57.34 ± 43.06% vs. 13.26 ± 19.04% vs. 37.76 ± 37.08%) and CI values. Conclusions It was concluded that (i) LC > LP abutments enhanced subepithelial connective tissue attachment and preserved crestal bone levels, (ii) repeated abutment dis‐/reconnection during the initial healing phase (4–6 weeks) may be associated with increased soft‐ and hard‐tissue changes and (iii) LP and LC should be considered using a one abutment, one time approach.