Svrha istraživanja bila je usporediti razlike u vrijednostima triju parametara boje gornjih desnih
središnjih sjekutića izmjerenih spektrofotometrom, te kalibriranih i nekalibriranih RAW i JPEG
formata fotografija snimljenih trima pametnim telefonima koristeći Smile Lite MDP uređaj.
U istraživanju je sudjelovalo ukupno 45 ispitanika. CIE L*a*b* vrijednosti na središnjoj trećini
gornjih desnih središnjih sjekutića izmjerene su spektrofotometrom i na RAW i JPEG
kalibiranim i nekalibriranim fotografijama snimljenima trima različitim pametnim telefonima
u različitim uvjetima osvjetljenja te sivom kalibrirajućom karticom. Boja zuba na fotografijama
mjerena je u kompjuterskom programu Adobe Lightroom 6. Dobiveni rezultati su međusobno
uspoređeni. Većina CIE L*a*b* vrijednosti na RAW i JPEG fotografijama na sva tri testirana
pametna telefona u različitim uvjetima osvjetljenja statistički su se značajno razlikovale
(p<0,05). Razlika u većini CIE L*a*b* vrijednosti boje između kalibriranih i nekalibriranih
fotografija na sva tri pametna telefona bila je statistički značajna (p<0,05). CIE L*a*b*
vrijednosti kalibriranih i nekalibriranih RAW i JPEG fotografija svih triju testiranih pametnih
telefona statistički su se značajno razlikovale (F=29.780; p=0.000). CIE L*a*b* vrijednosti na
nekalibriranim RAW fotografijama snimljenima iPhone 11 Pro pametnim telefonom uz
uporabu polarizacijskog filtera potpuno su se poklapale s istim vrijednostima izmjerenima
Različiti uvjeti osvjetljenja, postupci mjerenja, format fotografije i vrsta pametnog telefona u
ovom su istraživanju utjecali na CIE L*a*b* vrijednosti na fotografijama snimljenima
pametnim telefonom. Uz ograničenja ovog istraživanja moguće je zaključiti da bi se
nekalibrirana RAW fotografija snimljena iPhone 11 Pro pametnim telefonom, s polarizirajućim
filterom na prednjem diodnom svjetlu u standardiziranim uvjetima, mogla koristiti pri
digitalnom određivanju boje zuba.
|Abstract (english)|| |
Introduction: For many years dental professionals have been using dental photography for
diagnostic and treatment planning, documentation, publishing, education, marketing and
communication with patients, dental technicians and colleagues. More recently, dental
photography became very important for detecting facial pattern changes after orthodontic
treatment, maxillofacial surgery, prosthetic oral rehabilitation and digital smile planning.
Digital Single Lens Reflex (DSLR) cameras are considered as the “golden standard” cameras
used to take high quality dental photographs. Past few years smartphone cameras have advanced
in terms of sensor quality, resolution and lens sophistication and mobile dental photography is
becoming more and more popular among dentists. Digital shade measurement determining
tooth color was developed in order to reduce and overcome the inaccuracies and inconsistencies
of traditional methods of tooth shade determination. Studies have shown that
spectrophotometers are among the most accurate instruments for tooth color matching.
Spectrophotometer Vita Easyshade V has become a reference device for determining tooth
color in numerous clinical studies and has been used to determine the color of various dental
materials. Numerous studies have confirmed the accuracy and repeatability of color
measurements of these devices.
Aim: The purpose of the study was to compare the differences in the values of the three color
parameters of the upper right central incisors measured by a spectrophotometer, and calibrated
and uncalibrated RAW and JPEG digital photos taken with three smartphones using a Smile
Lite MDP device.
Participants and methods:
The study was conducted on 45 subjects. This study included those subjects with intact
permanent upper central incisor without fillings and caries, endodontic procedures and
prosthetic replacements, the presence of periodontal disease or any form of discoloration, and
those who do not have fixed orthodontic retainers and have not undergone teeth whitening
therapy for a year. The measurement took place in the research room without the natural light
source (no windows), with fluorescent lighting (4 x 120 cm, 36 W, color 765, Philips, Hamburg,
Germany), light temperature of 5080 K and illuminance of 500 lux measured using colorimeter
Chroma-2. At each measurement infection control shield was placed over the probe tip when
using Easyshade V spectrophotometer set in “tooth single” mode. The probe tip was positioned
on the surface of the central area of the middle third of each right maxillary central incisor and
this position was marked using a red waterproof marker to ensure later accurate positioning of
the digital probe. Before each measurement the device was calibrated according to the
All subjects were photographed in a standing upright position leaning against a wall with a
retractor placed in their mouth. Subjects held a grey card under the upper front teeth when
photographing, which serves as a color calibrator in digital image analysis. All photographs in
this study were taken using a Smile Lite Mobile Dental Photography device. The Smile Lite
MDP device was equipped with three different smartphones for photographing front teeth. Each
time the smartphones in the device were replaced, the subjects had their retractor removed from
their mouths to prevent dehydration. A total of 30 different photos in two formats (RAW and
JPEG) were made for each participante, 15 for each photo format.
All photos were imported to the computer program Adobe Photoshop Lightroom 6. All the
photos were measured two times, once with and once without special calibration using gray
card on the picture. For calibration white balance of each photo had to be carried out using the
measurement probe placed on one of four gray segments on the card while adjusting image
exposure balance by setting lightness (L*) at 75*, and a* and b* values at 0* on histogram.
Then the measurement of CIE L*a*b* values on the tooth were conducted setting the
measurement probe right in the middle of the red circle marked previously on each maxillary
right central incisor. When measuring with no calibration the measurement of CIE L*a*b*
values on the tooth were conducting immediately on the tooth, avoiding previous calibration of
the grey scale.
Results: Most CIE L*a*b* values on RAW and JPEG photographs on all three tested
smartphones in different lighting conditions were statistically significantly different (p<0.05).
The difference in most CIE L*a*b* color values between calibrated and uncalibrated
photographs on all three smartphones was statistically significant (p<0.05). CIE L*a*b* values
of calibrated and uncalibrated RAW and JPEG photos between all three tested smartphones
differed statistically significantly (F=29.780;p= 0.000). The CIE L*a*b* values on uncalibrated
RAW photos taken with an iPhone 11 Pro smartphone using a polarizing filter completely
matched the same values measured by the spectrophotometer (p>0.05).
Conclusions: Different lighting conditions, measurement procedures, and photo format in this
study influenced the CIE L*a*b* values on smartphone photos. With the limitations of this
research, it can be concluded that an uncalibrated RAW photo taken by an iPhone 11 Pro
smartphone taken with a polarizing filter on the front LED light could be used in digitally
determined tooth color under standardized conditions.