Department of Oral Sciences, Faculty of Dentistry, University of Otago, New Zealand.
Department of Oral Sciences, Faculty of Dentistry, University of Otago, New Zealand; Department of Surgical Sciences, University of Cagliari, Italy.
J Mech Behav Biomed Mater. 2023 Jul;143:105881. doi: 10.1016/j.jmbbm.2023.105881. Epub 2023 May 12.
Biofilm formation around orthodontic appliances causes gingivitis, enamel decalcification and caries. Bacteria adhere less readily to superhydrophobic surfaces. The aim of this study was to determine whether a superhydrophobic surface could be generated on orthodontic elastomers by surface modification in order to reduce bacterial adhesion.
Orthodontic elastomers were modified with sandpapers of various grit sizes (80-600 grit). Surface roughness of the modified and unmodified surfaces was assessed qualitatively with scanning electron microscopy and quantitatively with confocal microscopy. Water contact angles were measured with a goniometer to quantify hydrophobicity. Measurements were performed on unextended elastomers (100% original length) and elastomers extended to 150%, and 200% of the original length. Adhesion of Streptococcus gordonii to saliva coated elastomers was measured by counting colony forming units on agar plates.
Abrasion with different sandpapers produced elastomers with surface roughness (R) ranging from 2 to 12 μm. Contact angles followed a quadratic trend with a maximum contact angle of 104° at an R of 7-9 μm. Average water contact angles, when viewed perpendicular to the direction of extension, decreased from 99° to 90° when the extension was increased from 100% to 200% and increased from 100° to 103° when viewed parallel to the direction of extension. Bacterial adhesion increased as roughness increased and this effect was more pronounced with elastomer extension.
The surface roughness of orthodontic elastomers influences both their hydrophobicity and bacterial adhesion. Superhydrophobicity of elastomers could not be achieved with sandpaper abrasion.
正畸矫治器周围的生物膜形成会导致牙龈炎、釉质脱矿和龋齿。细菌不易附着在超疏水表面上。本研究旨在通过表面改性在正畸弹性体上产生超疏水表面，以减少细菌黏附。
用不同粒度的砂纸（80-600 目）对正畸弹性体进行改性。用扫描电子显微镜定性评估改性和未改性表面的表面粗糙度，用共聚焦显微镜定量评估。用接触角测量仪测量水接触角以量化疏水性。在未拉伸弹性体（原始长度的 100%）、拉伸至原始长度的 150%和 200%的弹性体上进行测量。通过在琼脂平板上计数菌落形成单位来测量唾液涂层弹性体上粘性链球菌的黏附。
用不同的砂纸打磨产生的弹性体表面粗糙度（R）范围为 2-12μm。接触角呈二次趋势，在 R 为 7-9μm 时达到最大接触角 104°。当从 100%拉伸到 200%时，垂直于拉伸方向观察时的平均水接触角从 99°下降到 90°，而当平行于拉伸方向观察时，接触角从 100°增加到 103°。随着粗糙度的增加，细菌黏附增加，这种效应在弹性体拉伸时更为明显。
正畸弹性体的表面粗糙度会影响其疏水性和细菌黏附。砂纸打磨无法实现弹性体的超疏水性。
