Summary  Prosthetic crowns made by galvano‐forming are considered to be highly biocompatible and aesthetic restorations. Therefore, they represent an alternative crown‐system to conventional metal‐ceramic crowns in replacing lost tooth structure. However, there are few data available on clinical and biochemical effects of galvano‐ceramic crowns on periodontal tissues. The purpose of this controlled study was to test the impact of galvano‐ceramic crowns and metal‐ceramic crowns on clinical and inflammatory responses of periodontal tissues. A prospective, blinded randomized clinical trial was conducted. Galvano‐ceramic crowns and metal‐ceramic crowns were placed in 52 periodontally healthy patients in split‐mouth design. Clinical parameters (gingival index, plaque index, probing depths and recessions) were recorded from six sites per tooth. Initial tissue alteration was accessed analysing the gingival crevicular fluid flow rate and IgG concentration in gingival crevicular fluid. After 24 months, 34 patients could be re‐evaluated. All crowns were in adequate function and obvious clinical inflammation was rarely observed. After 24 months of follow‐up, gingival tissues adjacent to galvano‐ceramic crowns showed significantly less signs of clinical and inflammatory responses according to plaque index (P = 0·004), gingival index (P < 0·001), gingival crevicular fluid flow rate (P = 0·012) and IgG (P = 0·002). Data were also analyzed for buccal and oral sites separately. Gingival tissues adjacent to metal‐ceramic crowns showed significantly increased clinical and inflammatory values for plaque index (P = 0·005), gingival index (P = 0·008), gingival crevicular fluid flow rate (P = 0·006), IgG (P = 0·007) at oral sites compared to galvano‐ceramic crowns. Our data suggest a stabilizing effect of galvano‐ceramic crowns on periodontal tissues over time.