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rev port estomatol med dent cir maxilofac . 2021;62(3):141-149 143

Table 1. Inclusion and exclusion criteria
Inclusion Criteria Exclusion Criteria
Be at least 18 years old Restored or non -vital anterior teeth
Absence of smoking habits Presence of periodontal disease or caries lesions
Willing to sign a consent form Being under orthodontic treatment
Have at least one anterior tooth (maxillary or mandibular) equal or Allergy to one of the components
darker than A3,5 in VITA Classic shade guide measurable by a
spectrophotometry Pregnancy or lactating women
Anomalies of tooth development or presence of severe tooth
discoloration
History of any medical disease that may interfere with the study or
require special consideration
Poor oral hygiene

brary of Medicine ClinicalTrials.gov website under the refer- system (CIE L*a*b* values of the buccal tooth surface), and the
ence number NCT03588871, in full compliance with the Hel- difference (ΔE ) was calculated to determine bleaching effec-
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sinki World Medical Association Declaration’s most recent tiveness. Tooth whiteness was evaluated with a whiteness in-
amendments. Patients were recruited consecutively, screened dex (WI ) specifically established for dentistry and based on
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according to inclusion and exclusion criteria (Table 1), signed the CIELAB color notation system. The whiteness index was
an informed consent form, and received professional dental assessed before (WI ) and after (WI ) the bleaching treatment,
D1
D2
prophylaxis. Then, they were randomly allocated to one of and then its difference was calculated (ΔWI ). 22
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two study groups (GraphPad QuickCals, http://www.graph-
pad.com/quickcalcs/randomize1.cfm), according to different
soft-tissue protection materials, for an in-office technique
protocol with a paint-on varnish at 6% HP concentration (Vi- The CIEDE2000 formula, from the Commission Internatio-
®
vaStyle Paint On PIus, lvoclarVivadent , Liechtenstein): Group nale De l’Eclairage (International Commission on Illumination)
1 – Vaseline (Purified Vaseline, Continente, SonaeMC, Maia, (CIE), was used to calculate ΔE . Computations with this color
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Portugal); Group 2 – block-out resin (OpaldamTM, Ultradent difference formula were performed according to the following
Products, Inc, USA). equation: 23
Two previously calibrated experienced dentists conducted Parametric factors were set to 1. The whiteness index was
in-office tooth bleaching using the 6% HP paint-on varnish calculated before and after tooth bleaching with the following
technique, following the described clinical protocol: an Op- formula: WI = 0.511L*-2.324a*-1.100b*. Color and whiteness
24
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tragate retractor was placed in the patient’s mouth (Optragate, difference perception was assessed according to two major
®
lvoclarVivadent , Liechtenstein); soft-tissue protection mate- thresholds: perceptibility threshold (PT for ΔE ; WPT for ΔWI )
00
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rials (Vaseline or block-out resin) were applied to the gingival at ΔE = 0.8 and ΔWI = 0.72; and acceptability threshold (AT
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margin to prevent contact with the peroxide varnish; one thin for ΔE ; WAT for ΔWI ) at ΔE = 1.8 and ΔWI = 2.60. 24-26 ΔWI
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and uniform layer of the paint-on varnish was applied to the evaluation followed Perez et al.’s classification system present-
buccal surface of maxillary and mandibular anterior teeth ed in Table 2. 26
(first pre-molar to first pre-molar); after 10 minutes, the var- The sample size was previously determined based on our
nish was easily removed using an ultrasonic scaling device; pilot study’s data, using an online calculator (http://powerand-
and paint-on layers were applied five additional times (10 min- samplesize.com). 18 Considering a mean ΔWI for teeth equal
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utes each), resulting in a total whitening procedure time of to or darker than A3.5 in VITA Classical (9.9 for Group 1 and
6
approximately 60 minutes per session. The clinical protocol 12.9 for Group 2) with a 3.2 standard deviation, we established
was performed in two appointments with a one-week interval that 20 patients (10 per group) would be needed for a two-sam-
and is illustrated in Figures 1 to 6 for Group 1 and Figures 7 to
14 for Group 2. Additionally, the presence or absence of soft-tis- 26
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sue lesions was recorded. Table 2. ΔWI classification system.
Tooth color was evaluated by spectrophotometry with a ΔWID 50:50%
proper device: SpectroShade micro (SS) (MHT Optic Research, Visual grading Threshold values
Niederhasli, Switzerland; serial number HDL3973). 19-21 The de- 0: No difference 0.70
vice was operated according to the manufacturer’s instructions
by an independent investigator, who performed three measur- 1: Small difference 1.57
ing rounds in upper and lower anterior teeth (canine to canine 2: Fairly acceptable difference 2.96
– 12 teeth). Results were registered before and after the tooth 3: Hardly acceptable difference 5.69
bleaching treatment in the CIE L*a*b* tooth color coordinates