Influence of coffee temperature and exposure parameters on colour change, surface roughness, and force remaining of orthodontic elastomeric chains: An in vitro comparison of cold, room temperature, and hot coffee.

OBJECTIVE

The study investigated the effects of coffee temperature, exposure interval, and immersion duration on the physical and mechanical properties of orthodontic elastomeric chains.

METHODS

White elastomeric chains were subjected to 300gf and exposed to coffee at three different temperatures: cold (4°C), room temperature (25°C), and hot (65°C), 1-3 times daily at 15minutes per exposure. Control groups were maintained in artificial saliva at 37°C. Colour change (ΔE) was quantified using a spectrophotometer, surface roughness (Sa) with a three-dimensional laser scanning microscope, and remaining force with a digital force gauge at 1, 7, 14, 21, and 28 days.

RESULTS

The results demonstrated time-dependent increases in ΔE and Sa values that were accompanied by progressive decreases in force remaining as immersion duration increased. At Day 28, the hot temperature group exhibited the highest ΔE values (mean 35.93; 95% CI: 35.23-36.62) and the lowest percentage of force remaining (mean 30.56%; 95% CI: 29.56-31.56%), followed sequentially by the room temperature, cold temperature, and control groups. Elastomeric chains exposed to coffee three times daily exhibited significantly greater ΔE values and lower remaining force compared with twice and once daily exposure groups (P<0.001). However, Sa values did not differ significantly among exposure intervals (Hot group Day 28 Sa mean: 1.50; 95% CI: 1.32-1.67). Three-way ANOVA revealed significant interactions among temperature, immersion duration, and exposure interval on values and force remaining (P<0.001).

CONCLUSION

Coffee consumption adversely affects elastomeric chains by increasing colour change and surface roughness, while reducing force remaining. These effects are influenced by coffee temperature, immersion duration, and exposure interval.