The enamel loss and adhesive remnants after bracket removal and various adhesive removal methods: an in vitro experimental study

Abstract

This study evaluated the effectiveness of various adhesive removal methods following orthodontic bracket debonding. Eighty extracted human premolars were bonded, debonded, and randomly assigned to four groups (n = 20) based on the adhesive removal method: (1) low-speed round tungsten carbide (TC) bur, (2) high-speed, 18-fluted tapered TC bur, (3) high-speed extra-fine needle-shaped diamond bur, and (4) sequential polishing discs. Each group was further subdivided into two subgroups (n = 10) based on the inspection method for surface cleanliness: tactile examination with a dental explorer or marking the surface with a black pencil. Adhesive removal time was recorded for each group, and surface roughness was measured. Pre- and post-treatment tooth surface scans were superimposed using Geomagic Wrap software to quantify enamel loss and residual adhesive height. Data were analyzed using two-way ANOVA (α = 0.05). The 18-fluted TC bur had the shortest adhesive removal time (52.80 ± 6.74 s) but caused the greatest enamel loss (70.56 ± 56.44 μm) and highest residual adhesive height (75.60 ± 57.35 μm) (P < 0.05). Surface roughness was significantly higher in the 18-fluted TC bur group (186.20 ± 65.98 μm) than in the polishing disc (123.70 ± 40.64 μm) group (P < 0.05). Adhesive removal time was significantly longer for the polishing disc group (P < 0.05). Using a black pencil for surface inspection did not affect enamel characteristics, but significantly increased treatment time (P < 0.001). A low-speed round-shaped TC bur or an extra-fine needle-shaped diamond bur is recommended for adhesive removal after bracket debonding. Enamel inspection with a dental explorer provides comparable results to black pencil marking regarding enamel preservation.