Development and performance of a clear aligner film loaded with sustained release hydrogen peroxide gel

Abstract

Introduction: Clear aligner treatment (CAT) has become popular over recent years because it is both comfortable and aesthetically acceptable. However, most of patients undergoing orthodontic treatment request dental bleaching. A safe and controlled bleaching treatment at the same time as the clear aligner treatment can save time and improve patient satisfaction with the outcome of the treatment.Aim: This study was aimed to develop a thermoforming film loaded with hydrogen peroxide as a clear aligner and detect its efficiency on teeth blenching and its influence on shear bonding strength for attachment.Methods: The thermoforming film loaded with sodium alginate-dopamine/Mesoporous silica nanoparticles compound gel was immersed in 6 wt% hydrogen peroxide solution and the hydrogen peroxide was loaded into mesoporous silica nanoparticle channels by capillary action. Then, a thermoforming film loaded with sustained-release hydrogen peroxide gel was made. Six dentition models were prepared with 90 isolated human premolars and divided into the experiment group, the condition control group and the blank control group, respectively. Then, the experiment group wore the clear aligner made by the thermoforming film loaded with hydrogen peroxide for 40 days; the conditional control group wore the clear aligner made by the ordinary thermoforming film for 40 days; and the blank control group wore no clear aligner. The aligners were updated every 10 days and the color of teeth was measured every 10 days. Tooth color should be determined by specific parameters (L, a* and b*). What’s more, in order to determine the influence of the thermoforming film loaded with sustained-release hydrogen peroxide gel on shear bonding strength for attachment. The shear bonding strength of attachment of isolated premolars were measured.Results: Isolated premolars treated by bleaching experiments showed an increase in L value (ΔL = 7.76 ± 0.64) and a decrease in both a* (Δa = −0.82 ± 0.12) and b* (Δb = −3.10 ± 0.21) values. However, the isolated premolars in conditional control group and blank control group exhibited that an decrease in L value (ΔLCCG = −0.91 ± 0.24; ΔLBCG = −0.86 ± 0.15)and a increase in both a* (ΔaCCG = 0.19 ± 0.05; ΔaBCG = 0.18 ± 0.04) and b* (ΔbCCG = 0.43 ± 0.11; ΔbBCG = 0.31 ± 0.10) value. While the shear bonding strength for attachment after bleaching was 22.78 ± 2.28 MPa, which had no significant change compared with the shear bonding strength for attachment without bleaching experiment (22.21 ± 2.77 MPa) (p > 0.05). Conclusion: A thermoforming film featuring the sustained release of hydrogen peroxide had a good bleaching effect on isolated teeth and had no significant influence on the shear bonding strength for attachment.