SEJ_2-2017_Articol_Ionescu
DENTAL MATERIALS
CALCIUM PHOSPHATE NANOPARTICLES REDUCE DENTIN HYPERSENSITIVITY:
Original Articles
A RANDOMIZED, PLACEBO-CONTROLLED SPLIT-MOUTH STUDY
Andrei C. Ionescu1a*, Elena M. Varoni2a, Gloria Cazzaniga1a, Marco Ottobelli1a, Eugenio Brambilla1b
1
Department of Biomedical, Surgical and Dental Sciences, IRCCS Galeazzi Orthopedic Institute, University of Milan, Via R. Galeazzi, 4, I-20161 Milan,
Italy
2
Department of Biomedical, Surgical and Dental Sciences, Dental Clinic ASST Santi Paolo e Carlo - Presidio Ospedaliero San Paolo, University of Milan,
Via Beldiletto, 1/3, I-20142 Milan, Italy
DDS, PhD
a
DDS, Professor
b
Received: May 05, 2017
Revised: May 29, 2017
Accepted: June 13, 2017
Published: June 14, 2017
Academic Editor: Nicoleta Ilie, Dipl-Eng, PhD, Professor, Department of Operative Dentistry and Periodontology, Faculty of Medicine,
Ludwig-Maximilians-Universität München, München, Germany
Cite this article:
Ionescu AC, Varoni EM, Cazzaniga G, Ottobelli M, Brambilla E. Calcium phosphate nanoparticles reduce dentin hypersensitivity: a randomized, placebo-
controlled study. Stoma Edu J. 2017;4(2):102-107.
ABSTRACT DOI: 10.25241/stomaeduj.2017.4(2).art.2
Introduction: Modern strategies for dental remineralization and prevention of dentin hypersensitivity
are increasingly based on biomimetic materials. The aim of this study was to assess the clinical efficacy
of a calcium-phosphate nanoparticles-based dentin desensitizer (DD, Teethmate Desensitizer,
Kuraray Noritake, Japan).
Methodology: 25 patients, requesting treatment after reporting sensitivity of non-carious cervical
lesions and dental abrasions were recruited. Inclusion criteria were: response score ≥6 on a 10
cm-long visual analog scale (VAS) for 1+ teeth in each of two quadrants. Exclusion criteria were:
presence of systemic diseases, ongoing analgesic therapy, pregnancy, presence of carious or pulpal
lesions, poorly contoured restorations, enamel cracks, active periodontitis and ongoing use of
desensitizing agents. The response was determined to 2 s air blast. VAS scores were collected at t=0
(PRE), immediately after treatment with the DD (POST), after 1 week, and after 1, 3 and 6 months. Half
of the sites in each patient (split-mouth) were randomly treated with a placebo, and scores collected
until after 1 week. The DD was then applied to the placebo sites.
Results: Both DD and placebo significantly decreased VAS scores on POST confronted to PRE
(p<0.0001), showing similar efficacy (35% and 28%, respectively). DD application further decreased
scores after 1 week (63%) while placebo application did not show significant differences confronted
to POST (p=0.09). DD scores maintained throughout the observational period the levels obtained
after 1 week.
Conclusion: The tested DD effectively reduced dentin hypersensitivity during 6-month follow-
up, after one single application. Biomimetic desensitizers may be an effective solution to dentin
hypersensitivity.
Keywords: biomimetic material, dentin hypersensitivity, desensitization, calcium-phosphate
nanoparticles.
1. Introduction therefore decrease pain perception. Since this
A short pain on exposed dentin, which can be discovery, many therapeutic approaches to dentin
elicited by thermal, evaporative, tactile, osmotic hypersensitivity have been employed.1,2,4,6 Less
or chemical stimuli,1 characterizes dentinal recent techniques were based on blocking the
hypersensitivity. It is now widely acknowledged nociceptive conduction (mainly using potassium
that dentin hypersensitivity derives from exposed salts), on the superficial blocking of the orifices of
dentin tubules, where stimuli excite pulp cells the tubules with different compounds (varnishes,
as proposed by BrannstrÖm’s hydrodynamic dentin bonding systems), or by inducing sclerosis
theory.2,3 According to that theory, the diameter of the tubules (SnF2, SrCl*6H2O, Al-, K-, Fe- oxalate,
of the exposed tubules and their density are the Fluorides, Na2FPO4). Lasers are also employed
factors that mainly influence hypersensitivity,4 as and have obtained positive results, but the exact
already highlighted by Yoshiyama et al.5 Finding mechanism is not fully understood, being likely due
a way to close the orifices of the tubules could to either tubule occlusion or superficial glazing.6
*Corresponding author:
Dr Andrei C. Ionescu, DDS, PhD, Post-doc fellow and tutor
Department of Microbiology, Via Pascal, 36, First floor, 20133 Milan, Italy, Phone: +390250319007, Fax: +390250319040, e-mail: andrei.ionescu@unimi.it
102 Stoma Edu J. 2017;4(2): 102-107 http://www.stomaeduj.com
CALCIUM PHOSPHATE NANOPARTICLES REDUCE DENTIN HYPERSENSITIVITY:
A RANDOMIZED, PLACEBO-CONTROLLED STUDY
A new possibility is provided by the introduction of eligible for this trial received extensive verbal and
Original Articles
biomimetic materials commonly used in dentistry. written information regarding possible benefits
These materials can mimic a few properties of and risks of the treatment. Patients were informed
the tissue they are replacing, and in particular the that one of the compounds tested is a placebo
use of nanotechnologies can help in obtaining and that, if they felt the treatment did not reduce
synthesis and precipitation of hydroxyapatite at dentin hypersensitivity, they could feel free to exit
tooth level, opening possibilities for bioactive the trial anytime and ask for alternative solutions.
compounds and biomaterials to remineralize 2.2. Subject selection
tooth structures, modulate biofilm formation, Patients visiting 3 different private practice
prevent caries occurrence and treat dentin dental offices in Northern Italy and requesting
hypersensitivity.7,8,9,10 Among several advantages treatment after reporting sensitivity were screened
that these remineralization techniques present, the for eligibility. Non-carious cervical lesions or
possibility of closing exposed orifices of dentinal dental abrasions might be, or not, present at the
tubules using these materials is promising. hypersensitive sites. The inclusion criterion was a
The aim of this study was to assess the clinical response score of ≥6 on a 10 cm long visual analog
efficacy, expressed as pain reduction from scale (VAS) that was numbered every centimeter
hypersensitive tooth areas, of a dentin desensitizer from 0 to 10, for at least one tooth in each of two
(DD) based on calcium phosphate nanoparticles. quadrants situated on the right-side and left-side
The null hypotheses were that (i) no differences of the mouth, so that a split-mouth model for test
are shown between the tested DD and a placebo and placebo compounds could be applied.
compound in pain reduction after one week of Exclusion criteria were the presence of systemic
follow-up, and (ii) no significant differences in the diseases, ongoing temporary or permanent
efficacy of the test compounds are found among analgesic therapy for any reason, pregnancy,
the evaluated time points. presence of carious or pulpal lesions, poorly
contoured restorations, presence of enamel cracks
2. Methods on the hypersensitive teeth, active periodontitis
2.1. Study design and materials and ongoing use of desensitizing agents of any
This study evaluated the efficacy of a calcium- kind. Patients were also excluded if the clinical
phosphate nanoparticles-containing DD (test DD, situation requested other treatments on the
Teethmate Desensitizer, Kuraray Noritake, Dental Inc. screened sites than desensitizing alone.
Okayama, Japan) on desensitization of non-carious The response was determined to a 2 s, cold air blast
cervical lesions and tooth abrasions. The test DD was from a dental syringe directed perpendicularly
compared with a placebo during the first 1 week to the tooth surface at approximately 5 mm
of evaluation in a trial designed as a randomized, distance. In the VAS scale, patients were told that
double-blind, placebo-controlled, split-mouth study. 0 indicated a well-being condition with complete
After that period, only the test DD was evaluated to absence of any pain, while 10 was the worst pain
assess its efficacy for up to 6 months. The composition they experienced or thought could ever exist. VAS
of the materials used in this study are displayed in scores collection was performed immediately after
Table 1; the powder and liquid were transferred from the air blast, patients being asked to point on the
the original packaging to glass bottles only identified VAS scale to the nearest full centimeter number
by letters, masking their content to both patient and describing their pain perception.
dental operator (double-blind trial). A total of 25 patients were recruited, and each
The ‘Guidelines for the design and conduct of had the hypersensitive sites assigned to test or
clinical trials on dentin hypersensitivity’ were placebo treatment according to a randomization
adopted and partly followed during the design list. Neither the patient nor the dentist performing
and execution of the study.11 desensitizing treatments knew if the treated area
The study was conducted in agreement with the belonged to the test or placebo compound, thus
principles of the Declaration of Helsinki updated obtaining a double-blind model. The patients’
by the World Medical Association in 2013.12 Before demographics were as follows: 9 males (32-57
obtaining written, informed consent, all patients years old) and 16 females (25-60 years old).
Table 1. Composition of the tested materials. Placebo was obtained using reagents purchased from Sigma–Aldrich
(St. Louis, MO, U.S.A.).
Material Powder Liquid
Teethmate Desensitizer Tetracalcium phosphate, TTCP; Ultrapure water
dicalcium phosphate anhydrous,
DCPA; sodium fluoride; glycerol;
polyethylene glycol
Placebo Glycerol monostearate; HPLC-grade water
polyethylene glycol (PEG3350)
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CALCIUM PHOSPHATE NANOPARTICLES REDUCE DENTIN HYPERSENSITIVITY:
A RANDOMIZED, PLACEBO-CONTROLLED STUDY
2.3. Application method ordinal VAS scores), were not normally distributed
Original Articles The targeted area was first cleaned with a cotton and homoscedasticity was not respected, non-
pellet. Then, the dentist mixed the powder with parametrical ANOVA and non-parametric
the liquid for 15 s to obtain a paste that was comparisons for each pair using Wilcoxon method
immediately applied on the treated areas with (p<0.05) were used to highlight significant
a microbrush by gently brushing for 2 min (Fig. differences between groups.
1 to 4). In the same visit, both test and placebo
treatments were applied to each patient according
to a randomization list. Patients were then asked
to rinse their mouth, and within 15 min after the
treatment the blinded dentist applied the same air
blast stimuli under the same conditions to assess
pain scores after treatments (POST). Patients were
recalled for hypersensitivity assessment of the
treated areas after 1 week. At that time point, after
data collection, both dentist and patients were un-
blinded regarding the test or placebo treatment,
and the test treatment was applied to the area Figure 3. Dental occlusal erosions bilaterally on palatal
that previously received the placebo compound. side of maxillary frontal and lateral teeth. Air blast test scored
Patients were then recalled after 1, 3 and 6 months 8. Patient was referred to a gastroenterologist physician. He
and at each recall the dentist assessed only tooth was later diagnosed with gastroesophageal reflux disease
(GERD) and given treatment. Patient refused restorative
areas that were treated with test compound since therapies, requesting treatment of pain symptoms only.
the beginning of the trial.
Figure 4. Application of the test DD on the same area as in Fig 3.
Figure 1. Patient requesting desensitization treatment for
vestibular areas of maxillary teeth. No presence of cervical
lesions or abrasions could be identified as well as other 3. Results
lesions, yet upper right and upper left canines and premolars
scored 7 on VAS after air blast test.
All 25 subjects completed the trial without requesting
alternative desensitization treatments or dropping
out from the trial. No adverse reactions were
reported. The results of the study are displayed in
Fig. 5. Both DD and placebo significantly decreased
VAS scores comparing POST and PRE (p<0.0001)
measurements, thus showing similar efficacy (35%
and 28%, respectively). DD application further
decreased scores after 1 week (63% in comparison
with PRE), while placebo application did not show
significant differences when compared to POST
(p=0.09). The scores from the areas treated with
the DD maintained, throughout the observational
period, the levels obtained after 1 week (maximum
Figure 2. Application of the tested DD on right maxillary decrease in scores = 69% after 3 months). At 6
teeth (test site), same area depicted in Fig 1. months, a small, non-significant increase in VAS
scores was also observed.
2.3. Statistical analysis
All statistical analyses were performed using
4. Discussion
statistical software (JMP 10.0, SAS Institute Inc, Cary,
Dentin hypersensitivity is an increasing occurrence,
NC, USA). A preliminary check of the normality of
and dental materials or procedures able to reduce
distribution and homogeneity of variances was
the patient’s sensitivity are increasingly needed. A
performed using Shapiro-Wilk’s and Levène’s tests
variety of therapies are currently available,2,4,6 but
(p<0.0001 and p=0.0014, respectively). Since
the most modern and biocompatible approach
data did not belong to continuous variable (0-10
104 Stoma Edu J. 2017;4(2): 102-107 http://www.stomaeduj.com
CALCIUM PHOSPHATE NANOPARTICLES REDUCE DENTIN HYPERSENSITIVITY:
A RANDOMIZED, PLACEBO-CONTROLLED STUDY
seems to be the one aiming at reconstituting layer with dentin surfaces, enhancing mineralization
Original Articles
a barrier and closing the open orifices of the under oral conditions.17 The data obtained in this
tubules by using biomimetic materials and study could convey some indirect hints regarding
techniques.13,14,15,16 the activity of the compound. It seems clear that the
deposition of an amorphous layer of nanocrystals on
the hypersensitive tooth surfaces does not lead to a
reduction in pain perception greater than placebo
effect. It is very likely, however, that hydroxyapatite
and fluorapatite deposition inside dentinal tubules
takes place at least over a one-week time period
after application and is responsible for the significant
reduction in pain perception when confronted to
the placebo at 1 week or to the initial values. Our
results confirm the assumptions of Zhou et al.10 thus
providing a clinical confirmation of their in vitro
results. In their study, the effectiveness of the same
DD was evaluated in reducing dentin permeability
and tubule orifice occlusion. It was found that the
two parameters improved depending on the time
until maximum values in permeability reduction
and tubules occlusion were found after one week.10
These results are in good correlation with those of
the present study, meaning that dentine permeability
and occlusion of tubuli orifices (>50%) can be good
Figure 5. Box plot depicting the main findings of the study. The indicators of reduction in pain perception.
minimum and maximum values and the 25th, 50th, and In our study, it was found that the reduction in
75th percentiles are shown in red. Different superscript letters pain perception due to the test DD did not remain
indicate significant differences between groups (p<0.05) as significantly different between the different time
assessed by Wilcoxon method. The test DD was compared with a points starting from 1 week for up to 6 months. This
placebo for up to 1 week, then its effect on reducing pain
means that the effects obtained by the tested DD
perception was monitored for 6 months.
(remineralization, reduction in dentin permeability
and tubule occlusion)10,17 are long-lasting, however
In this study, we assessed the clinical efficacy,
additional studies are needed to ascertain if the test
expressed as pain reduction from hypersensitive
DD may express its activity over extended observation
tooth areas, of a biomimetic, hydroxyapatite-forming
times up to one or several years.
dentin desensitizer (DD) based on calcium phosphate
The study was performed under conditions as
nanoparticles.
close as possible with those of similar studies14,15 in
The first null hypothesis could not be fully rejected,
order to evaluate possible differences yielded from
since immediately after application there was no
geographical areas or pain perception. The tested
significant difference between DD under investigation
DD compound was the same as the one used by
and placebo, meaning that the reaction to the test
Mehta et al. in 201414 and similar to the one tested by
DD immediately after application could not be due
the same research group one year after.15 The study
to its activity, but simply to a placebo effect. After
design was the same as in Mehta et al., 2015,15 except
one week, however, there was a highly significant
for the placebo follow-up that was stopped after 1
difference between placebo and test DD. In fact, the
week in the present study. The statistical analysis was
test DD required 1 week to reach the significantly
different in methodology, since in the present study
lowest scores of pain perception, and this level was
no parametric analysis of data could be applied. One
maintained for up to 6 months. The second null
would speculate that, given that the material, the
hypothesis could, therefore, be rejected.
study design and the patient recruitment were very
The tested DD is a biomimetic desensitizing
similar among these studies, similar results would be
compound based on the reaction between
obtained. A first observation can be made comparing
tetracalcium phosphate and dicalcium phosphate
the initial pain scores to those after treatment and
anhydrous in the presence of fluoride ions. Once
1-week follow-up. The initial scores in the present
water is added, the reaction produces hydroxyapatite
study were higher than those from Mehta et al.,14,15
and small parts of fluorapatite nanoparticles
and reduction in pain perception after at least one
that precipitate as an amorphous layer on the
week of treatment was higher than the results of
tooth structures. Since nanocrystal deposition on
Mehta et al.,15 but similar to the results the same
enamel and dentin structures is driven by collagen
Authors obtained one year earlier.14
backbone structures, one may speculate that the
Many different explanations for these results may
presence of these structures inside dentine tubules
be provided, including the fact that pain remains an
may help organize deposition of hydroxyapatite
extremely subjective perception being influenced
and fluorapatite. Thanatvarakorn et al. in 201317
by many confounding factors such as the socio-
provided some data in support of this hypothesis.
economic-religious environment. This difference
They showed that the tested DD developed an
shows the importance of performing several studies
immediate reduction in dentin permeability and an
with different populations from as many different
effective integration of the calcium phosphate rich
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CALCIUM PHOSPHATE NANOPARTICLES REDUCE DENTIN HYPERSENSITIVITY:
A RANDOMIZED, PLACEBO-CONTROLLED STUDY
environments as possible, particularly when testing longer than the minimum amount of time necessary
Original Articles the clinical behavior of therapies influencing a to assess a difference between placebo and test (1
patient’s pain perception. From this point of view, the week), since this would provide patients with further,
setting itself where the investigations were carried unnecessary discomfort.
out may be an additional confounding factor, since in Another difference in the study design regarded the
the present study it was constituted by some private assessment of hypersensitivity, since in the present
dental clinics while Mehta et al. evaluated patients study, contrary to Mehta et al.,14,15 it was decided not
seeking cure at a hospital Dental College.14,15 Apart to use the scrape test. The guidelines on conducting
from the aforementioned factors, this distinction trials on dentin hypersensitivity suggested, as an
may have had an influence on the general health example of response-based method, the use of cold
expectations patients had. stimuli, such as timed air blast, or tactile stimuli.11 In
An additional difference between our study and that the study conducted by Mehta et al, as well as in many
of Metha et al.15 is that the latter evaluated Teethmate other studies, response was evaluated using both
AP paste, produced by the same manufacturer as air blast and the tactile running of a dental explorer
the desensitizer tested here. The main difference across the cervical area of the assigned teeth, in
between the two products is that the paste is a water- horizontal and vertical direction at a “relatively mild
free calcium phosphate compound, while the test DD force”. If one considers the microscopical and sub-
used in this study is a mixture of calcium phosphate microscopical structure of enamel and dentine,
powder with water, containing an accelerator that however, it is clear that the tactile test is invasive and
leads upon mixture and application to the reaction may produce damage to tooth structures at that level.
producing and precipitating hydroxyapatite Furthermore, tactile tests, if applied immediately after
nanocrystals.18 Comparing all findings, the pain desensitization, may locally disturb the precipitated
reduction obtained by the paste desensitizer was layer of nanocrystallites, hampering their further
slower and more moderate than that of the DD tested deposition and organization to occlude dentin tubule
in this study. orifices. For this reason, any contact test was avoided
According to Holland et al.,11 assessments were in the present study, and further studies may be
made between contralateral teeth, and one side performed to assess the influence of tactile stimuli on
of the mouth served as a control for the other side the behavior of biomimetic hydroxyapatite-forming
(split-mouth model). A randomization list was dentin desensitizers.
used to assign each side to either test or control
treatments. The comparisons were made between 5. Conclusion
an active treatment (test DD) and a placebo that The results obtained in this study showed that the
had aspect and composition identical to the active tested DD effectively reduced patient discomfort
treatment, save for the active principles. In a previous caused by dentin hypersensitivity during a 6-month
study15comparisons were made between a similar follow-up, up to 69% after 3 months, after one single
DD and distilled water (placebo) for up to 6 months. application. Biomimetic, hydroxyapatite-forming
In a pilot study we performed on 3 patients (data not desensitizers may be an effective solution to dentin
shown), we saw that differences between placebo hypersensitivity.
and test compounds were noticeable as of 1 week
after treatment. It must be noted that all enrolled Disclosure
patients of this study reported discomfort levels in No conflict of interest exists for any of the Authors of
response to air blast ≥6 on VAS scale, and the tested the paper.
treatment aimed to reduce pain perception. Contrary This research did not receive any specific grant from
to the study design adopted by Mehta et al.,15 in funding agencies in the public, commercial, or not-
the present study it was therefore decided not to for-profit sectors.
prosecute observations on the placebo group for
References
1. Dowell P, Addy M. Dentine hypersensitivity-a review. 6. Sgolastra F, Petrucci A, Severino M, et al. Lasers for
Aetiology, symptoms and theories of pain production. J the treatment of dentin hypersensitivity: a meta-
Clin Periodontol. 1983;10(4):341-350. Review. analysis. J Dent Res. 2013; 92(6):492-499. Review. doi:
[Full text links] [PubMed] Google Scholar(314) Scopus(163) 10.1177/0022034513487212.
2. West NX. Dentine hypersensitivity: preventive and [Full text links] [PubMed] Google Scholar(54) Scopus(23)
therapeutic approaches to treatment. Periodontol 2000. 7. Ferraz MP, Monteiro FJ, Manuel CM. Hydroxyapatite
2008;48(1):31-41. doi: 10.1111/j.1600-0757. nanoparticles: a review of preparation methodologies. J
[Full text links] [PubMed] Google Scholar(114) Scopus(66) Appl Biomater Biomech. 2004;2(2):74-80.
3. Brännström M. A hydrodynamic mechanism in the [PubMed] Google Scholar(297)
transmission of pain-produced stimuli through the dentine. 8. Zakaria SM, Sharif Zein SH, Othman MR, et al. Nanophase
In: Anderson DJ, editor. Sensory mechanisms in dentine. hydroxyapatite as a biomaterial in advanced hard
London: Pergamon Press; 1963. tissue engineering: a review. Tissue Eng Part B Rev.
Google Scholar(358) 2013;19(5):431-441. Review. doi: 10.1089/ten.
4. West NX, Lussi A, Seong J, et al. Dentin hypersensitivity: TEB.2012.0624.
pain mechanisms and aetiology of exposed cervical dentin. [Full text links] [PubMed] Google Scholar(106) Scopus(77)
Clin Oral Investig. 2013;17(1):9-19. doi: 10.1007/s00784- 9. Ionescu AC, Hahnel S, Cazzaniga G, et al. Streptococcus
012-0887-x. mutans adherence and biofilm formation on experimental
[Full text links] [Free full text] [PubMed] Google Scholar(73) composites containing dicalcium phosphate dihydrate
Scopus(38) nanoparticles. J Mater Sci Mater Med. 2017;28(7):108. doi:
5. Yoshiyama M, Masada J, Uchida A, et al. Scanning electron 10.1007/s10856-017-5914-7.
microscopic characterization of sensitive vs. insensitive [Full text links] [PubMed] Google Scholar(0) Scopus(0)
human radicular dentin. J Dent Res. 1989;68(11):1498- 10. Zhou J, Chiba A, Scheffel DL, et al. Effects of a dicalcium
1502. doi: 10.1177/00220345890680110601 and tetracalcium phosphate-based desensitizer on in vitro
[Full text links] [PubMed] Google Scholar(182) Scopus(105) dentin permeability. PloS one. 2016;11(6):e0158400. doi:
106 Stoma Edu J. 2017;4(2): 102-107. http://www.stomaeduj.com
CALCIUM PHOSPHATE NANOPARTICLES REDUCE DENTIN HYPERSENSITIVITY:
A RANDOMIZED, PLACEBO-CONTROLLED STUDY
10.1371/journal.pone.0158400. containing paste on dentin hypersensitivity. Dent Mater.
Original Articles
[Full text links] [Free PMC Article] [PubMed] Google 2015;31(11):1298-1303. doi: 10.1016/j.dental.2015.08.162.
Scholar(3) Scopus(1) [Full text links] [PubMed] Google Scholar(5) Scopus(3)
11. Holland GR, Narhi MN, Addy M, et al. Guidelines for 15. Sauro S, Lin CY, Bikker FJ, et al. Di-calcium phosphate and
the design and conduct of clinical trials on dentine phytosphingosine as an innovative acid-resistant treatment
hypersensitivity. J Clin Periodontol. 1997.24(11):808-813. to occlude dentine tubules. Caries Res. 2016;50(3):303-
[Full text links] [PubMed] Google Scholar(529) Scopus(304) 309. doi: 10.1159/000445444.
12. Mitchell JC, Musanje L, Ferracane JL. Biomimetic dentin [Full text links] [PubMed] Google Scholar(1) Scopus(0)
desensitizer based on nano-structured bioactive glass. 16. Thanatvarakorn O, Nakashima S, Sadr A, et al. Effect of a
Dental Materials. 2011;27(4):386-393. doi: 10.1016/j. calcium-phosphate based desensitizer on dentin surface
dental.2010.11.019. characteristics. Dent Mater J. 2013;32(4):615-621.
[Full text links] [PubMed] Google Scholar(45) Scopus(25) [Full text links] [Free article] [PubMed] Google Scholar(18)
13. Mehta D, Gowda VS, Santosh A, et al. Randomized Scopus(16)
controlled clinical trial on the efficacy of dentin 17. Chow LC. New generation calcium phosphate-based
desensitizing agents. Acta Odontol Scandin. biomaterials. Dent Mater J. 2009;28(1):1–10.
2014;72(8):936-941. doi: 10.3109/00016357.2014.923112. [Full text links] [Free PMC Article] [PubMed] Google
[Full text links] [PubMed] Google Scholar(24) Scopus(11) Scholar(190)
14. Mehta D, Gowda V, Finger WJ, et al. Randomized, placebo-
controlled study of the efficacy of a calcium phosphate
Andrei Cristian IONESCU
DDS, PhD, Post-doc fellow and tutor
Department of Biomedical, Surgical and Dental Sciences
IRCCS Galeazzi Orthopedic Institute
University of Milan, Milan, Italy
CV
He graduated with top marks in Dentistry and Oral Prosthetic Rehabilitation at the University of Milan, Italy, in
2008. He got his PhD in Nanotechnologies at the University of Trieste, Italy, in 2015. Since 2005 he has been
working at the Oral Microbiology Laboratory of the University of Milan, director Prof. Eugenio Brambilla, where
he has been a research coordinator as of 2013. He authored 25 publications in peer-reviewed journals. He
won the Paffenbarger Award of the Academy of Dental Materials, the Robert Frank Award of the Continental
European Division, International Association of Dental Research (CED-IADR) and the Espertise contest of
3M Oral Care. He is a promoter of the Young Researchers Group of CED-IADR. His main research interests
include the study of bioactive and biomimetic materials, antimicrobial compounds and their interactions with
oral biofilms.
Questions
What is a biomimetic material?
qa. A material that is only made of biological parts taken from natural tissues;
qb. A material able to reproduce some features and properties of a natural tissue;
qc. A material that reacts with the environment in a different way than a natural tissue does;
qd. A material that does not react in any way with the environment or with the host.
Which one cannot be the mechanism of action of a dentin desensitizer?
qa. It can block pain stimuli by blocking nervous transmission, for instance using potassium salts;
qb. It can demineralize dentin surface, thus leaving more tubule orifices open to the oral environment;
qc. It can cause sclerosis of the tubuli, thus reducing their lumen until the tubule is closed;
qd. It can cause deposition of crystals inside tubuli, thus closing their orifices.
Which of these factors must be exclusion factors for subject recruitment when conducting a
trial on dentin sensitivity?
qa. Subjects already using a desensitizing toothpaste;
qb. Subjects permanently using analgesic therapies;
qc. Subjects younger than 30;
qd. Subjects presenting carious lesions.
If a test treatment shows a positive effect confronted to the baseline, but the effect is non-
significantly different from that of a placebo, what conclusions can be drawn?
qa. The test compound is performing better than the placebo;
qb. The test compound is not safely applicable to human subjects;
qc. The test compound does not perform better than the placebo;
qd. The placebo effect is not visible in the test.
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