One challenge faced by dental professionals is that, unlike natural tooth structure, composite restorations do not lighten when exposed to bleaching agents. As a result, functional restorations may need replacement after bleaching to match the newly whitened teeth. However, replacing a composite restoration can lead to unnecessary removal of tooth structure, potentially weakening the tooth and increasing its susceptibility to further iatrogenic damage. This study will investigate the ability of Omnichroma restorations to shade-match tooth structure after bleaching.
The null hypotheses will be:
1. Single-shade RBC will not exhibit similar shade and optical behavior to conventional RBC across all anterior restorations following bleaching. 2. Patient satisfaction regarding color blending between the restoration and tooth structure will not differ according to the type of material used. 3. Dentist satisfaction regarding color blending between the restoration and tooth structure will not differ according to the type of material used.
Patients who are willing to come back for follow-up appointments.
Patients who are willing to sign an informed consent form.
Patients with well documented clinical records and have at least two anterior restorations (both Omnichroma and conventional multi-shade nanohybrid composite.)
Patients aged 18 years or older.
Individuals with severe bruxism or periodontal disease.
Patients with non-vital teeth restored with composite fillings.
Patients with severe tooth discoloration.
Patients with fluorosis or tetracycline staining.
Parallel
Conventional nanohybrid multishade composite and hydrogen peroxide 40% in-Office Tooth Whitening System
DrugTeeth restored with conventional multi shade nanohybrid Resin Based Composite (RBC) Filtek Z350Xt (3M ESPE, San Paul, MN, USA) subjected to bleaching using Opalescence Boost 40% In-Office Tooth Whitening System (Ultradent, Utah, USA)
Single shade nanohybrid composite and hydrogen peroxide 40% in-Office Tooth Whitening System
DrugTeeth restored with One-shade Resin Based Composite (Omnichroma, Tokuyama Dental, Tokio, Japan) subjected to bleaching using Opalescence Boost 40% In-Office Tooth Whitening System (Ultradent, Utah, USA)
Color measurements using digital spectrophotometer VITA Easyshade V.
The colour measurements will be taken at first session for each tooth in specific points as follow: One reading from middle part of tooth Three readings at three points around the restoration and 1 mm away from its margins. To give a chance for tooth rehydration and final color optimization, a new reading will be obtained from the middle portion of the restoration after one week. The color difference (∆E00) between the tooth structure around the restoration and the restoration itself will be calculated. The color difference (∆E00) between the tooth and restoration will be compared between the control and test groups. The final ΔE00 value itself has no physical unit. It is just a numerical representation of color difference.
Subjective or Patient satisfaction
Patient satisfaction regarding color blending between the restoration and tooth surface will be recorded after one week using visual analogue scale (VAS). The scale is a horizontal line with 10 digits, where 0 (on the right) represents total dissatisfaction with color blending between the tooth and restoration, and 10 (on the left) indicates complete satisfaction. Patients will mark their satisfaction with the color matching and blending of the restoration on the VAS. Measurements will be categorized as follows: Poor: VAS values from 0 to 5 Good: VAS values from 5.1 to 10
Objective or dentists satisfaction
Photographs of the restored teeth will be taken under a standardized setup using a Canon 250D DSLR camera, a Sigma 105 mm macro lens, and a Meike MK-14EXT TTL macro ring flash. The images will be evaluated by two calibrated dentists who are blinded to the restoration material. Blending with the tooth surface will be assessed using VAS, with the assessors marking their evaluation on the scale. Measurements will be divided according following criteria: Poor: VAS values ranging from 0-5. Good :VAS values ranging from 5.1-10.
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