Introduction: Coated archwires improve aesthetics because of the tooth-coloured appearance. However, colour change of the coated archwires have been reported in vitro. Nonetheless, little is known to what extent this colour change occurs clinically. This second part of the multi-centre, double-blind, randomised controlled trial evaluated the colour change (∆E*) of three coated archwires with their controls and patient perception. Methods: 84 patients who received treatment with upper and lower fixed appliance treatment were invited. Consented patients were randomised to receive one of four treatment interventions using 0.014” superelastic nickel-titanium archwires from (1) Orthocare (2) RMO (3) G&H, and (4) 3M Unitek® uncoated. These archwires were ligated during bonding and collected after 8th week. After removal, the digital images of the archwires were assessed for colour change using Adobe® Photoshop® software, and the CIE L*a*b* system was used to calculate the ΔE* values. Patient perception was measured using oral aesthetic subjective impact scale (OASIS) questionnaire. Results: For colour change and patient perception assessment, 132 archwires from 66 participants who had been treated with aesthetic archwires were collected. Two fractured archwires were excluded. Initial analysis revealed all three aesthetic archwires groups showed significant mean of ∆E* with the highest was found in Orthocare (23.9), and the lowest is G&H (16.8). Post hoc comparison revealed statistically significant mean of ∆E* in Orthocare when compared with other groups (p <0.001). There was no statistically significant difference for patient perception between archwire groups. Conclusion: Preliminary results revealed that significant ∆E* in Orthocare group and patients showed positive perception following clinical use
Craniofacial & ; Biomaterial Sciences Cluster, Advanced Medical & ; Dental Institute, Universiti Sains Malaysia, 13200 Kepala Batas, Penang, Malaysia. 2 School of Dental Sciences, Universiti Sains Malaysia (Health Campus), 16150 Kubang Kerian, Kelantan, Malaysia

Colour stability of the material is an essential factor that contributes to the selection of a flexible denture material. Staining effects on the denture may result in unattractive appearance, the dissatisfaction of the wearer, and limited usage period of the denture. This study aims to identify the colour stability of the Valplast flexible denture material using three types of beverages. Methods: A total of 32 disc-shaped flexible resin materials (20 +/- 0.1 mm in diameter and thickness 3 +/- 0.1 mm) were prepared based on the manufacturer instructions. The samples were randomly divided into 4 groups of immersion: distilled water (control), coffee solution, tea solution and red wine. The samples were left in the specified immersion solution for up to 60 days. Colour changes were measured after 1, 3, 7, 14, 21, 30, 45 and 60 days of immersion. Results: The samples immersed in coffee solution changed from S1 to S2, whereas samples in tea solution changed from S1 to S3. Additionally, samples in red wine changed from S1 to S4, as observed using the Valplast colour tone guide. The highest reflection measured using spectroscopy was 65.146 at 385.19 nm of the control samples, whereas the lowest reflection was 1.974 at the wavelength of 385.97 nm on the samples immersed in the red wine. Conclusion: The most significant difference can be observed in the red wine group, followed by samples in tea and coffee solutions. Moreover, increasing the immersion period causes increasing staining effect of the denture.
Craniofacial and Biomaterial Sciences Cluster, Advanced Medical and Dental Institute, Universiti Sains Malaysia, 13200, Bertam, Penang, Malaysia 2 Institut Latihan Kementerian Kesihatan Malaysia (Pergigian), No.3 Jalan Sepoy Lines, 10450 Georgetown, Penang, Malaysia 3 Division of Research and Networking, Advanced Medical and Dental Institute, Universiti Sains Malaysia, 13200, Bertam, Penang, Malaysia 4 School of Physics, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia