Expression of artefacts from different orthodontic brackets and wires in cone beam computed tomography scans-an in vitro study

Objectives: To investigate artefacts produced by different orthodontic brackets and wires in cone-beam computed tomography (CBCT) scans.

Materials and methods: Two dental arches were made using extracted human teeth and plaster. Three pairs of acetate plates containing different brackets - metallic, ceramic, and self-ligating ceramic with NiTi clip - along with a control plate (i.e., without brackets) were prepared. Wire changes (NiTi and steel) were made during CBCT acquisitions, performed with a fixed exposure protocol. Axial slices were selected for mean gray values and standard deviation measurement in three regions of interest (buccal, lingual, and tooth). Noise and contrast-to-noise ratio (CNR) were calculated and compared among the different brackets and wires by ANOVA with a significance level of 5%.

Results: Overall, the buccal and tooth region were mostly affected by the metallic and self-ligating brackets, showing higher noise, and lower CNR (p < 0.05). On the other hand, less impact of ceramic brackets in the image quality was observed (p ≥ 0.05). The lingual region did not show expressive differences among the brackets and wire combinations (p ≥ 0.05). The presence of wire associated with the brackets did not worsen image quality (p ≥ 0.05).

Conclusions: In conclusion, metallic and self-ligating brackets have greater artefact expression than ceramic brackets. The wire did not influence image quality.

Clinical relevance: One should pay attention to the type of brackets when requesting a CBCT scan during treatment, as metallic and self-ligating brackets may express greater artefacts than ceramic brackets.