Background. The surface properties of brackets and archwires and their possible intraoral degradation might affect the friction force and hence the effectiveness of orthodontic treatment. Aim. The aim was to assess the influence of long-term wear, debris accumulation and archwire material on friction force among different types of brackets and archwires couples. Material and Methods. As-received and used brackets (conventional [CB1 and CB2] and self-ligating [SLB]) and archwires (nickel-titanium [NiTi] and stainless steel [SS]), retrieved form 36 subjects undergoing orthodontic treatment, were included in the study. The surface characteristics of as-received and used brackets and archwires were analyzed by Scanning Electron Microscopy (SEM) with Energy Dispersive Spectroscopy (EDS) and the morphology of brackets was assessed on microCT scans. Quantitative assessment of debris accumulation was performed on pictures of brackets obtained using SEM and its composition was analyzed by EDS and Fourier-Transform Infrared spectroscopy. The triboelectrochemical properties of as-received and used NiTi and SS archwires was evaluated using a tribometer. The friction testing was performed among four lower incisors’ brackets, of each type coupled with either NiTi or SS archwires. Non parametric tests were used for statistical analysis. Results. The surface characteristics of used brackets and archwires were significantly different and more debris and surface degeneration changes were seen on used material. However, this did not affect the triboelectrochemical properties of orthodontic archwires. Only bracket type was significantly correlated with the friction force (p<0.001). Significantly higher friction force (p≤0.001) was seen in used SLB in comparison with as-received SLB. Conclusions. The intraoral degradation processes of orthodontic appliances affect their surface characteristics, however their effectiveness in terms of low friction tooth movement might be either improved or worsen depending upon a complex synergistic or antagonistic effect of different variables. In particular, performance of orthodontic appliances is mainly affected by brackets’ characteristics.