Effect of Chemical and Light Bleaching Techniques on Color Change, Dentin Hypersensitivity and Patient Satisfaction

patients attending the faculty clinic will be screened and selected for the studyaccording to the following inclusion criteria and exclusion criteria, inclusion criteria; ‐ Patients must be between 18 and 45 years old to avoid hypersensitivity resultingfrom the immature pulp in young populations, or the apparent yellowish color ofdentin resulting from enamel wear in older populations. ‐ Presence of six sound maxillary anterior teeth. ‐ Patient having brown or yellowish stains. ‐ Good oral health maintained by routine brushing. ‐ Generalized tooth staining ranging from A2 or darker according to the value‐orientedshade guide (Vita easy shade). ‐ Patient is willing to sign a consent form and can attend all recall visits.Exclusion criteria: ‐ Existing anterior crowns or any restorations on anterior teeth that will interferewith the bleaching process. ‐ Smoker or alcoholic patient. ‐ Patients suffering from active periodontal diseases and exposed roots. ‐ Patient who undergone previous whitening procedure. ‐ Pregnant and lactating women. Thirty‐two patients will be selected for the study.Oral hygiene steps will be taken at the first visit, as well as scaling andpolishing of the teeth. Patients will be divided into two groups according to thebleaching technique used. Group 1: chemical bleaching, Group 2: light activatedbleaching.Bleaching techniques: ‐ Chemically activated bleaching: the patient's lips will be covered in Vaseline forprotection, a cheek retractor is used to pull the lips and cheeks away from theteeth to shield them from the bleaching gel and to prevent gel leakage, the gingivais properly dried, and a gingival protector liquid dam is added to all exposedgingiva and cured according to the manufacturer's instructions. Bleaching gel isuniformly added to the teeth and bleaching procedure will be conducted according tothe manufacturer's instructions in one session for 20 min. ‐ Light activated bleaching: same protection protocol is used in addition toprotective eye wear for both patient and operator. Bleaching gel is uniformly addedto the teeth and light bleaching procedure will be conducted according to themanufacturer's instructions in one session for 20 min.Color change measurements:Tooth color measurements will be performed at baseline T0, immediately after bleachingtreatment T1, 1‐week T2 and 1‐month T3 after bleaching using a spectrophotometer. Themeasured values will be recorded in the units of CIELab color space. CIE L* parametershows the degree of lightness, a* is indicative of redness/greenness, and b* indicatesyellowness/blueness. Variations in L*, a*, and b* axes and chromatic alteration will beperformed at each period and compared to baseline using the following calculation: ΔE* =[(ΔL*)2 + (Δa*)2 + (Δb*)2]1/2.Whiteness index (WID):The whiteness index will be also calculated to verify the perceived bleaching effect. TheWID is a simple linear formulation that uses the CIELab chromatic coordinate values, inwhich the higher the values obtained, the greater the bleaching effect provided by agiven procedure. WID will be calculated using the following formula: WID = (0.511 × L ∗)‐ (2.324 × a ∗) ‐ (1.100 × b ∗).Evaluation of postoperative dentin hypersensitivity:Dentin hypersensitivity will be evaluated at baseline D0, immediately after bleachingtreatment D1, 1 week (D2) and 3 month (D3) after bleaching using Visual Analogue ScaleVAS numbered from 0 (no pain) to 10 (maximum extreme pain).Evaluation of patient satisfaction:At the end of the study (3 months) a questionnaire was given to the patients to assesstheir satisfaction with bleaching treatment. Multi‐item measure of satisfaction will beused to evaluate patients' perceptions of importance and performance of fourcharacteristics of a bleaching treatment; final tooth color, color stability, length oftreatment and comfort during treatment. Patients will be asked to rate the perceivedimportance of each characteristic on a 7‐point Likert scale anchored by 1='Not at allimportant' and 7='Very important'. The perceived performance of each characteristic willbe assessed on a scale anchored by 1='Very bad' and 7='Excellent'. Difference betweenperformance and importance scores of individual service characteristics will be thencalculated to form a third variable, the gap score, which will be used as an indicator ofpatient satisfaction. Also, the overall satisfaction of patients with the bleachingservice will be measured separately on a 7‐point scale anchored by 1='Not at allsatisfied' and 7='Very satisfied'.