Surface Roughness, Biofilm Accumulation, and Acidogenic Potential of Esthetic Orthodontic Brackets Exposed to Cigarette Smoke

Purpose To evaluate the effect of cigarette smoke on esthetic brackets. Methods Four commercial brackets ( n = 112), Ceramic ® , Composite ® , PolySafira ® , and Zetta ® were exposed for 21 consecutive days to cigarette smoke. The control group consisted of each bracket material maintained in artificial saliva and not exposed to cigarette smoke. Linear surface roughness was measured before and after exposure using optical profilometry, and surface morphology was qualitatively characterized by scanning electron microscopy (SEM) after the exposure period. Subsequently, the brackets were subjected to an acidogenic challenge in a multispecies biofilm with 2% sucrose. After 48 h, biofilm viability was assessed (CFU/mL), and the culture medium pH was analyzed. The data were analyzed using the Kruskal–Wallis test followed by the Mann–Whitney U test with Bonferroni correction, and a paired t -test ( p < .05). Results Zetta ® showed the greatest increase in Ra (+0.27 µm), and Ceramic ® exhibited a slight increase (+0.06 µm). Composite ® and PolySafira ® demonstrated a reduction in Ra values ( p < .05). Composite ® accumulated the highest amount of viable biofilm (6.44 × 10 4 CFU/mL), whereas Ceramic ® presented the lowest (3.56 × 10 4 CFU/mL). All groups showed a significant pH reduction after biofilm formation, with Composite ® demonstrating the most pronounced acidification (pH 6.5–5.2) and Ceramic ® the least (pH 6.8–5.9). Conclusions Cigarette smoke exposure adversely affected surface characteristics and acidogenic potential in esthetic orthodontic brackets. Ceramic ® showed lower biofilm accumulation and less pronounced surface roughness changes, while PolySafira ® showed stable surface behavior, and Zetta ® and Composite ® were more susceptible to surface alterations and biological challenges.