Study

Measurement method

Inclusion/exclusion

Cronin 2005

The CIE L*a*b* System used in digital colour analysis expresses 3 referenced colour co‐ordinate values: L, a, and b. L indicates lightness or brightness, and the co‐ordinates a and b indicate varying amounts of red/green and yellow/blue, respectively. Quantifying colour through the use of devices with this digital technology is possible. More importantly, it offers an objective way of determining the differences in tooth colour and studying the effects of whitening agents.

Exclusion criteria: subjects with anterior restorations covering more than 25% of the facial surfaces of the maxillary anterior teeth, orthodontics, previously bleached teeth within the last 6 months.

Gerlach 2003

Digital images of the facial surfaces of the 6 maxillary anterior teeth were collected at baseline and day 15.

Inclusion criteria: healthy adult with 4 maxillary anterior teeth with shade of "A2" or darker. Exclusion criteria: prior bleaching, current tooth sensitivity, or extensive restorative dentistry or orthodontics appliances involving the facial surfaces of the maxillary anterior teeth.

Gerlach 2002b

Digital image analysis: evaluation of teeth whiteness was carried out using Chroma Meter (Shade Eye‐EX) (Shofu Dental Corp, Menlo Park, CA 94025). Delta
L*, Delta a*, Delta b* represent standard colour space as whiteness/brightness from dark‐to‐light, green‐to‐red, and blue‐to‐yellow respectively.
Participants were positioned in a chin rest and aligned with the aid of a video image. Standardized intra‐oral lighting was achieved.
Values were determined for each pixel with reference to a calibration standard, and these values were averaged across all 6 maxillary anterior teeth.
Whitening benefit was defined as tooth colour change from baseline assessed by the digital imaging measurements Delta b* yellow‐blue, Delta L* light‐dark, and Delta a* is red‐green.
Negative Delta b* (reduction in yellow), and positive Delta L* (increased brightness) were considered to be indicative of a whitening benefit.

Inclusion criteria: healthy adults who desired to have their teeth whitened.
Excluded criteria: history of previously bleached teeth, current tooth sensitivity, or presence facial anterior restorations.

Karpinia 2002

Digital image analysis: to measure teeth whiteness this study used Chroma Meter (Shade Eye‐EX) (Shofu Dental Corp, Menlo Park, CA 94025).
Participants were positioned in a chin rest and aligned with the aid of a video image. Standardized intra‐oral lighting was achieved.
Values from all 12 anterior teeth were averaged to determine overall red green‐blue value for each visit. These values were translated into Delta L*, Delta a*, and Delta b*.

Inclusion criteria: healthy adults with at least 4 maxillary anterior teeth with a tooth shade of A2 or darker as measured using a 16‐tab shade guide.
Exclusion criteria: oral conditions requiring emergency treatment, tooth sensitivity, or a history of previous vital bleaching.

Gerlach 2002a

Digital image analysis (Sh‐HC1000 CCD).
Participants were positioned in a chin rest and aligned with the aid of a video image. Standardized intra‐oral lighting was achieved.
Values from 6 anterior maxillary teeth were averaged to determine overall red green‐blue value for each visit. These values were translated into Delta L*, Delta a*, Delta b*.
Whitening benefit was defined as tooth colour change from baseline assessed by the digital imaging measurements Delta b* yellow‐blue, Delta L* light‐dark, and Delta a* is red‐green.

Inclusion criteria: adults 18 years or older with no prior bleaching history, no tooth sensitivity, no restoration on facial of anterior teeth, no prophylactic for at least 3 months.

Gerlach 2000

Digital image analysis.
The system used in this study was described as "high resolution digital camera (Fuji HC 1000 CCD) with motorized lens connected to a computer".
Participants were positioned in a chin rest and aligned with the aid of a video image. Standardized intra‐oral lighting was achieved.
Values from all 12 anterior teeth were averaged to determine overall red green‐blue value for each visit.
The values were translated into Delta L* a* b*.

Exclusion criteria: sensitive teeth, past tooth whitening, or restorations involving anterior teeth.
Inclusion criteria: healthy adult volunteers.

Gerlach 2001

Digital image analysis.
The system used in this study was described as "high resolution digital camera (Fuji HC 1000 CCD) with motorized lens connected to a computer".
Participants were positioned in a chin rest and aligned with the aid of a video image. Standardized intra‐oral lighting was achieved.
All 6 anterior teeth were measured twice and the scores each colour co‐ordinate and tooth were averaged.

Subjects were assigned after balancing for tooth colour, coffee or tea drinking, and tobacco use, and demographics.
Exclusion criteria: sensitive teeth, past tooth whitening, or restorations involving anterior teeth.
Inclusion criteria: healthy adults.

Kowitz 1994a

Reflectance Spectroscopy: baseline colour measurements were taken on the mid‐facial aspects to each upper central incisor with a small area colorimeter using a custom fabricated silicone jigs to ensure repeatable positioning of the meter. Each reading was repeated 3 times to obtain a mean baseline colour before treatment.

Inclusion criteria: healthy subjects with discolouration equal to or darker than A3 on the Vita Shade Guide.
Exclusion criteria: not reported.

Kowitz 1994b

Reflectance Spectroscopy: baseline colour measurements were taken on the mid‐facial aspects to each upper central incisor with a small area colorimeter using a custom fabricated silicone jigs to ensure repeatable positioning of the meter. Each reading was repeated 3 times to obtain a mean baseline colour before treatment start.

Inclusion criteria: healthy subjects with discolouration equal to or darker than A3 on the Vita Shade Guide.
Exclusion criteria: not reported.

Matis 2000

Digital image analysis: Chroma Meter measures L*, a*, b* colour spaces.
Trubyte Bioform colour Ordered Shade Guide.
Measurements from 6 maxillary anterior teeth were used.
Photographs were used to train in colour matching.

Inclusion criteria: all 6 maxillary anterior teeth had to be present. None of the maxillary anterior teeth could have more than 1/6 of the labial surface covered with a restoration, and the location of a restoration could not interfere with colorimeter placement. The patient had to be at least 18 years of age. The patient had to be willing to refrain from use of tobacco products during the study period.
Exclusion criteria: the use of a professionally applied or prescribed tooth whiteners, in‐office bleaching, or mouth‐guard vital bleaching in the past 3 years. Incisors or canines lighter than B54 or darker than B85 on the Trubyte Bioform colour Ordered Shade Guide. Gross pathoses in the oral cavity. Loe & Silness gingival index score greater than 1. Pregnancy or lactation. Teeth discoloured by tetracycline staining.

Mokhlis 1999

Matching with a shade guide, comparing right and left sides of clinical photographs, using colorimeter.
At each visit the colour of the 6 anterior teeth was measured 3 times, and then averaged.
Using colour photographs taken by Kodak Elite II, 100, 35 mm colour slide film, independently evaluators categorized each side of the mouth using 0 = no, 1 = slight, 2 = moderate, 3 = large.
Trubyte Bioform colour Ordered Shade Guide, 1 experienced evaluator.

All subjects had tooth cleaning performed by a hygienist prior to the study.
Exclusion criteria: medical reasons, gingival index greater than 1, pathological lesions, tetracycline stain, previously bleached teeth, use of tobacco, tetracycline stained teeth.
All subjects received $100.
Inclusion criteria: adult subjects must have all 6 maxillary anterior teeth. None of the teeth have more than 1/6 of the labial surface covered with restorations. Subjects should be willing to sign a consent form and are able to return for recall examination and refrain from the use of tobacco.

Panich 2001

Degree of teeth whiteness was measured using Chroma Meter 321. Eichhold positioning system was used to ensure the colorimeter could return to its predetermined position at baseline.
Slides were projected 3x5 feet and scored using the following scale: 0 = no, 1 = slight distinguishable, 2 = moderate or pronounced, 3 = large or dramatic.
Trubyte Bioform colour Ordered Shade Guide 1 shade was added to represent lightest than the lighter shade available.

Inclusion criteria: adult subjects must have all 6 maxillary anterior teeth. None of the teeth have more than 1/6 of the labial surface covered with restorations. Subjects should be willing to sign a consent form and are able to return for recall examination and refrain from the use of tobacco.
Exclusion criteria: history of medical diseases, bleeding tendencies, rheumatic fever, heart pacemaker, prosthetic joint, or heart valve. Use of tobacco during the study.
Gross pathology. Discoloured teeth due to tetracycline staining. Pregnant or lactating women. Incisors lighter than B54. Used whitener before. Gingival index score higher than 1.0.

Nathoo 1994

Reflectance Spectroscopy: Minolta Chroma Meter. All readings were carried out by the same investigator and under colour balanced operatory light to avoid error.

Inclusion criteria: Shade of teeth A3 or darker.
Exclusion criteria: not reported.

Li 2003

Chroma Meter evaluation was carried out using Minolta CR‐221, calibrated according to the manufacturer's instructions. The measurements were taken directly from the facial surfaces of 6 anterior teeth.

Inclusion criteria: subjects were required to have all maxillary anterior teeth present with minimum shade of A3 or darker. Exclusion criteria: subjects wearing orthodontic appliances; subjects with crowned anterior teeth or had periodontal disease, 5 or more carious lesions, pregnant or lactating, previously used tooth whiteners, or had oral pathologies.

Gerlach 2004

Digital image analysis: subjects were positioned in a chin rest, then images of the anterior facial tooth surfaces were captured using a high‐resolution digital camera (Fuji HC1000 CCD, Fuji Photo Film Co., Tokyo, Japan) and motorized zoom lens under standard polarized lighting conditions.

Inclusion criteria: healthy adult volunteers with no history of vital bleaching or dental prophylaxis within the past month. Exclusion criteria: individuals with tooth sensitivity, extensive restorative dentistry involving the anterior dentition, or fixed or orthodontic devices on the maxillary anterior teeth.

Karpinia 2003

Digital image analysis.

Inclusion criteria: healthy adults volunteers who consented to have their teeth whitened, or evidence of tooth sensitivity, previous tooth whitening, or restorative dentistry on the facial surfaces of the anterior teeth. Exclusion criteria: not reported.

Gerlach 2004

Digital image analysis: objective colour measurement using the L* a* b* colour scale of the Commission International del'Eclairage.

Inclusion criteria: healthy adults. Exclusion criteria: not reported.

Study ID

Measurement method

Inclusion/exclusion

Barnes 1998

Vita Shade Guide.

Adults with good general and dental health and with good oral hygiene.

Brunton 2004

Vita Shade Guide with 16 tabs. 1 examiner recorded the shade values of the labial surfaces of the maxillary anterior teeth.

Inclusion criteria: healthy adults with at least maxillary anterior teeth present with a minimum shade of A3 and available for the 6 months of the study. Exclusion criteria: adults with orthodontic appliances, soft tissue pathology, moderate or advanced periodontal disease, 5 or more carious lesions, pregnant or lactating, history of allergy to any whitening products, or restorations of teeth to be scored.

Cronin 2005

Tooth shades of the 4 maxillary incisors was visually graded using the Vita Shade Guide. The assessment was made under standardized lighting conditions immediately after wiping the teeth dry.

Exclusion criteria: subjects with anterior restorations covering more than 25% of the facial surfaces of the maxillary anterior teeth, orthodontics, previously bleached teeth within the last 6 months.

Kihn 2000

Value‐oriented Vita Lumen (Vita Zahnfabrik, Germany).

Healthy adults with at least A3 or darker anterior tooth colour as recorded using Vita Lumin. In good general and dental health.

Kugel 2000

Vita Shade Guide was used to measure whiteness of the 6 maxillary anterior teeth. B1 represented a score of 1, while C4 represented a score of 16. A decrease in Vita Shade Guide score represented an increase in tooth whiteness.

Exclusion criteria: active caries, hypersensitivity, tetracycline stain, fluorosis, and previous bleaching of teeth.

Li 2003

Vita Shade Guide was used to measure whiteness of the 6 maxillary anterior teeth.

Inclusion criteria: subjects were required to have all maxillary anterior teeth present with minimum shade of A3 or darker. Exclusion criteria: subjects wearing orthodontic appliances; subjects with crowned anterior teeth or had periodontal disease, 5 or more carious lesions, pregnant or lactating, previously used tooth whiteners, or had oral pathologies.

Li 2004

Same as Li 2003.

Same as Li 2003.

Mokhlis 1999

Trubyte Bioform Colour Ordered Shade Guide.

All subjects had tooth cleaning performed by a hygienist prior to the study.
Exclusion criteria: medical reasons, gingival index greater than 1, pathological lesions, tetracycline stain, previously bleached teeth, use of tobacco, tetracycline stained teeth.
All subjects received $100.
Inclusion criteria: adult subjects must have all 6 maxillary anterior teeth. None of the teeth have more than 1/6 of the labial surface covered with restorations. Subjects should be willing to sign a consent form and are able to return for recall examination and refrain from the use of tobacco.

Nathoo 2003

Vita Shade Guide with 16 tabs.

Inclusion criteria: subjects with all maxillary anterior teeth; free from large restorations; and with Vita Shade score of A3 or darker. Exclusion: similar to Li 2004.

Nathoo 2002

Same as Nathoo 2003.

Same as Nathoo 2003.

Sielski 2003

Vita Shade Guide.

Inclusion criteria: same as Li 2003.

Author, year

Masking

Randomisation

Assessor training

Follow up

Degree of bias

Barnes 1998

1. Yes
2. Yes
3. No
Note: 1 Examiner masking (yes, no); 2 = subject masking (yes, no); and 3 = masking of data analysts (yes, no)

Paired lists of names were supplied to the manufacturer, who assigned 1 member to the control group and 1 to treatment group Concealed: yes

Calibrated clinicians

Yes (at least 80% ) (No < 80%)
83%

Moderate

Brunton 2004

1. Yes
2. Yes
3. No

Randomised into 2 groups
Concealed: not reported

Not reported

Yes
96%

High

Cronin 2005

1. Yes
2. No
3. No

Subjects were stratified according to baseline Vitapan Classical shade scores and gender
Concealed: not reported

Training and reliability of the examiner was not reported

Yes
93.3%

High

Gerlach 2004

1. Yes
2. Yes
3. No

Not reported
Concealed: not reported

Training and reliability of the examiner was not reported

Yes
100%

High

Gerlach 2002b

1. Yes
2. No
3. No

Not reported
Concealed: not reported

Training and reliability of the examiner was not reported

Yes
98%

High

Gerlach 2000

1. Yes
2. No
3. No

Protocol: not reported
Concealed: not reported

Not reported

Yes
88%

High

Gerlach 2001

1. Yes
2. No
3. No

Protocol: not reported
Concealed: not reported

Not reported

Yes
85%

High

Gerlach 2002a

1. Yes
2. Yes
3. No

After balancing for baseline colour, subjects were randomised
Concealed: not reported

Not reported

Yes
91% at 2 weeks
86% at 6 months
Yes
91% at 2 weeks
86% at 6 months

High

Gerlach 2004

1. Yes
2. No
3. No

Subjects were randomly assigned Concealed: not reported

Training and reliability of the examiner was not reported

Yes
97%

High

Gerlach 2003

1. Yes
2. Yes
3. No

Protocol: not reported
Concealed: not reported

Training and reliability of the examiner was not reported

Yes
98%

High

Karpinia 2002

1. No
2. Yes
3. No

The study group was randomised in blocks of 4, balancing for initial tooth colour
Concealed: not reported

Not reported

Yes
99%

High

Karpinia 2003

1. No
2. Yes
3. No

Protocol: not reported
Concealed: not reported

Training and reliability of the examiner was not reported

Yes
96%

High

Kihn 2000

1. Yes
2. Yes
3. No

The subjects were randomly assigned by the company
Concealed: yes

Calibrated clinician

Yes
92%

Moderate

Kowitz 1994a

1. Yes
2. Yes
3. No

Protocol: not reported
Concealed: not reported

Not reported
Concealed: not reported

Yes
96%

High

Kowitz 1994b

1. Yes
2. No
3. No

After balancing for baseline colour, subjects were randomised to either group Concealed: not reported

Not reported

Yes
96%

High

Kugel 2000

1. Yes
2. Yes
3. No

Randomised with a block‐randomisations protocol using Vita Shade Guide score at baseline and gender Concealed: not reported

A standardized, trained, and calibrated examiner was used

Yes
94%

High

Li 2003

1. Yes
2. Yes
3. No

Using randomisation scheme generated by computer software and balanced with average Vitapan Classical shade and age
The group assignment was carried out by the project co‐ordinator without the knowledge of the investigators Concealed: yes

Training: not reported
2 examiners evaluated tooth colour independently and reached consensus

Yes
92%

Two examiners evaluated tooth surfaces independently and reached consensus

High

Li 2004

1. Yes
2. Yes
3. No

Subjects were stratified according to baseline Vitapan Classical shade scores and age, and were randomly assigned within each strata to 1 of the 3 groups Concealed: not reported

Trained and experienced examiner

Yes
86.6%

High

Matis 2000

1. Yes
2. Yes
3. No

The subjects were randomised into groups, according to baseline shade, by an assistant not directly involved in the study. Concealed: yes

1 examiner: experienced

Yes
100%

Moderate

Mokhlis 1999

1. Yes
2. Yes
3. No

Randomised according to the baseline shade guide into 2 groups by a study monitor not directly involved in the study. Concealed: yes

Evaluators were calibrated using colour slides, if differences existed consensus was reached using clinical photographs comparisons.
No consensus mentioned for shade guide matching. It was actually carried out by an "experienced examiner"

Yes
96%

Moderate

Nathoo 1994

1. Yes
2. Yes
3. No

Protocol: not reported
Concealed: not reported

Not reported

Yes
95%

High

Nathoo 2003

1. Yes
2. Yes
3. No

Qualifying subjects were stratified according to gender, age, and baseline VITA Shade Guide scores, and were randomly assigned within strata to 1 or 2 of the 2 study treatments. Concealed: not reported

A single, experienced, trained examiner performed all of the clinical examination

Yes
100%

High

Nathoo 2002

1. Yes
2 . Yes
3. No

Qualifying subjects were stratified according to gender, age, and baseline VITA Shade Guide scores, and were randomly assigned within strata to 1 of the study treatment groups. Concealed: not reported

1 experienced and trained examiner performed all clinical examinations

Yes
96%

High

Panich 2001

1. Yes
2. No
3. No

The patients were placed into 2 groups, according to baseline shade B56 or lighter and B77 or darker. A staff person not associated with the study did the assignment. Concealed: yes

2 evaluators calibrated in a previous study

Yes
100%

High

42 days

Sielski 2003

1. Yes
2. No
3. No

Qualifying subjects were stratified according to gender, age, and baseline VITA Shade Guide scores, and were randomly assigned within strata to one of the 2 study treatment groups. Concealed: not reported

1 experienced and trained examiner performed all clinical examinations

Yes
100%

High

Study ID

Side effects

Barnes 1998

There was no significant difference in average sensitivity between the active whitener group and the placebo group at the end of 2 weeks. There were no significant changes in gingival condition for either groups between baseline and 2 weeks.

Brunton 2004

Gingivitis scores were reduced from 0.91 to 0.44 (statistically significant).
85% of the subjects reported no tooth sensitivity. 13% reported moderate sensitivity, and 12% reported moderate‐severe tooth sensitivity. 15% reported moderate gingival sensitivity.

Cronin 2005

Not reported.

Gerlach 2004

Tooth sensitivity was more common in the experimental group at 42% while the control group had a prevalence of 26%. 11% of subjects in both groups had oral irritation.

Gerlach 2002b

Tooth sensitivity: 20% in the strip group; 10 % in the tray group. Gingival irritation: 30% in strip and 0 % in the tray.

Gerlach 2000

Tooth sensitivity and gingival irritation were mild to moderate in severity and were transient. The higher the concentration of the peroxide the higher was the sensitivity. The 20% CP product caused 60% tooth sensitivity compared to 9% and 10% in the 10% CP and 15% CP groups.

Gerlach 2001

Tooth sensitivity was more common in the strip group while gingival irritation was more common in the tray system.

Gerlach 2002

A total of 4 subjects (13%) of the study population reported tooth sensitivity at some time during the trial. 3 subjects reported gingival irritation.

Gerlach 2004

Oral irritation and tooth sensitivity were the most common adverse events in the study with 30% of the subjects experiencing one or both of these conditions sometimes during treatment.
The tray group had 33% (5 subjects) mild oral irritation and 33% mild tooth sensitivity while 21.4% of the dentifrice group had mild oral irritation. The paint‐on group had 0% observed or reported irritation and sensitivity.

Gerlach 2003

2 subjects reported tooth sensitivity, 1 in each treatment group. 1 subject in the 19% SP reported mild oral irritation. All adverse events were mild in severity, and no subject discontinued treatment because of product related adverse events.

Karpinia 2002

Tooth sensitivity and oral irritation were the most common adverse events reported. Tooth sensitivity was more common in the strip group at 26% compare to 15% in the tray group.

Karpinia 2003

Transient tooth sensitivity and oral irritation were the most common findings. A total of 29 subjects (51%) reported oral irritation or tooth sensitivity and 10 subjects (18%) had treatment related oral irritation. Tooth sensitivity was more common in the strip group, whereas oral irritation was more common in the combination system group. Both were mild in severity.

Kihn 2000

There was a significant difference in tooth sensitivity associated with use of 10% CP versus use of 15% CP (10% = 2.44 and 15% = 4.58). Incidence of tooth sensitivity was equal between the 2 groups.

Kowitz 1994a

No adverse reactions were clinically evident or reported.

Kowitz 1994b

Tooth sensitivity was reported in 1 subject who dropped out of the study.

Kugel 2000

In the placebo group, 1 patient had slight cervical inflammation over 1 tooth. 1 patient developed a minor superficial cervical lesion on 1 tooth and a second patient a swollen papilla between 2 adjacent teeth. Tooth sensitivity was unremarkable in both groups.

Li 2003

No tooth sensitivity was detected in any subject during clinical examination. Tooth sensitivity reported by the subjects ranged from 11.5% to 19.2% for Crest Whitestrips, 25%‐41.4% for Day White, 8%‐24% for Nite White.
Gingival irritation: the highest reported was in the Day White group (40.7%‐62.3%), while Crest Professional Whitestrips (7.7%‐23%). The Nite White group ranged from 0% to 12% gingival irritation. It was mild in nature, although several subjects in the Day White group reported severe gingival irritation.

Li 2004

Tooth sensitivity: 1 subject reported having mild tooth sensitivity.
There was no significant change in gingival irritation. No subjects complained of any treatment hypersensitivity regardless of the regimen used.

Matis 2000

No statistically significant difference between products was found for gingival sensitivity. Although there was a trend toward greater tooth sensitivity with the 15% product, the difference between products was not statistically significant at the 5% level.

Mokhlis 1999

Both products caused tooth sensitivity and gingival sensitivity. There was no difference between the 2 products.

Nathoo 1994

No adverse reactions were clinically evident or reported.

Nathoo 2003

No adverse reaction reported by the subjects or noted by the examiner.

Nathoo 2002

Throughout the study no adverse effects were associated with the use of either of the 2 treatments.

Panich 2001

CP caused more gum sensitivity than HP. CP and HP were equal in causing tooth sensitivity, and statistically not significant.

Sielski 2003

No adverse effects on the oral hard or soft tissue were observed by the examiner or reported by the subjects when questioned.