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December 2017Abstracts
Correspondence between fiber post and drill
dimensions for post canal
Ricardo Pablo Portigliatti, dds,
ms, José
Luis Tumini, dds, ms, Alejandro Daniel Bertoldi Hepburn, dds
Abstract: Purpose: To compare fiber posts of several calibers and
trademarks to their corresponding root canal preparation drills. Methods: Three widely used endodontic
post brands and their drills were evaluated: Exacto, ParaPost Taper Lux, and
Macro-Lock Illusion X-RO. Fiber posts and drills were microphotographed with a
scanning electron microscope and images were analyzed using ImageJ image
processing software. Fiber post diameter on apical extreme (Pd0), fiber post
diameter at 5 mm from the apical extreme (Pd5), drill diameter on apical
extreme (Dd0) and drill diameter at 5 mm from the apical extreme (Dd5) were
analyzed. The data were statistically analyzed using student t-test. Results: Exacto posts 0.5 showed larger
dimensions than their corresponding drills (P< 0.05) at Pd0. Macro-Lock
posts showed no significant differences vs. their drills at Pd0 in any of the
studied groups. ParaPost drills 4.5, 5 and 5.5 were statistically significantly
larger than their posts at Dd0 (P< 0.05). Exacto posts 0.5 and 1 showed
larger dimensions than their drills measured at Pd5 (P< 0.05). Exacto posts
number 2 showed smaller calibers than their corresponding drills at Pd5 (P<
0.05). Macro-Lock drills number 4 and ParaPost drills number 5 were larger than
their posts at Dd5 (P< 0.05). (Am J
Dent 2017;30:295-298).
Clinical significance: Poor spatial correspondence
between post and drill dimensions can adversely affect the film thickness of
the resin cement, diminishing bond strength due to polymerization shrinkage.
The lack of correspondence in size between posts and drills may lead to the formation
of empty chambers between the post and endodontic obturation with excessive
luting cement thickness, thus inducing critical C-Factor stresses.
Mail: Dr. R.P. Portigliatti,
Endodontic Specialization Training Program, Maimónides University, Hidalgo 775,
2nd floor, C1405BCK, Buenos Aires, Argentina. E-mail: rportig@intramed.net
CAD/CAM post-and-core using different esthetic
materials:
Fracture resistance and bond strengths
Denis Roberto Falcão Spina, dds,
ms, Rogério
Goulart da Costa, dds, ms, phd, Isabelli
Carolini Farias,
Abstract: Purpose: To evaluate the fracture
resistance (FR), and push-out bond strengths (BS) of custom-made CAD/CAM
post-and-cores manufactured with different esthetic materials. Methods: 90 single-rooted extracted
teeth were selected, endodontically treated and prepared to receive the posts.
The specimens were randomly divided into three equal groups according to the
material: hybrid ceramic Vita Enamic (HC); nano-ceramic resin composite Lava
Ultimate (RC); and experimental epoxy-resin reinforced by glass-fiber (FG). The
post-and-cores were manufactured using CAD/CAM and cemented using a self-adhesive resin cement (Rely X Unicem2). A subgroup of
30 specimens (n=10) was subjected to fatigue (1,000,000 cycles at 5 Hz) and
then to the FR test. Another subgroup with 60 specimens was submitted to the BS
test, with and without fatigue. Data were submitted to analysis of variance (FR
- one-way ANOVA; BS - two-way ANOVA) and Tukey’s test (α= 0.05). Results: The FR values (mean±SD, in
Newtons) were 414.5±83.9 (HC), 621.3±100.3 (RC), and 407.6±109.0 (FG), with RC
showing significantly higher FR values (P< 0.05). For BS, there was no
statistically significant difference among the materials, with and without
fatigue (P> 0.05). The type of material used to obtain the
CAD/CAM-customized post-and-cores had a significant effect on the FR, but not
on the BS of the specimens. Fatigue did not influence the BS for the tested
materials. (Am J Dent 2017;30:299-304).
Clinical significance: CAD/CAM custom-made esthetic
post-and-cores showed good performance relative to fracture resistance and bond
strength to root canal dentin walls. The CAD/CAM materials tested could be used
as an alternative to restore wide flared root canals in esthetically
compromised teeth.
Mail: Dr. Gisele Maria Correr, Graduate Program in
Dentistry, University Positivo, Rua Professor Pedro Viriato
Parigot de Souza 5300, Curitiba, PR, 81280-330, Brazil. E-mail: gmcnolasco@gmail.com
Fluoride release and re-release from a bioactive
restorative material
Elizabeth May, dds, ms & Kevin J. Donly, dds, ms
Abstract: Purpose: To compare the amount of fluoride release and re-release
of three different restorative materials. Methods: The three restorative materials included a resin-based composite
(Z100TM, 3M-ESPE), a resin-modified glass ionomer cement (VitremerTM, 3M-ESPE)
and a bioactive material (Activa Bioactive-RestorativeTM, Pulpdent,). Ten disks
were fabricated from each material. The disks were immersed in deionized water and
stored. Samples were taken from each vial on Days 1, 7, 14 and 30 for fluoride
ion analysis. Each disk was then exposed to 2.0% neutral sodium fluoride gel
(0.9% fluoride ion, Dentsply), immersed in deionized water and stored. Samples
were taken on
Days 1, 7, 14 and 30 for fluoride ion analysis utilizing a fluoride-specific
ion-analyzer. Results: Z100 released
less fluoride on Days 1 (P< 0.001), 7 (P= 0.001) and 14 (P< 0.022) for
Phase I (initial release) than Phase II (re-release). Vitremer and Activa
released less fluoride on Days 7, 14 and 30 (P< 0.001) for Phase II than
Phase I. For all intervals of Phase I, Vitremer released the most fluoride,
Activa released the second most, and Z100 released the least. These results
were the same for Days 7, 14 and 30 of Phase II. The level of fluoride release
from Activa was less than that of Vitremer, and greater than that of Z100 for
all intervals of Phase I. The results were the same for all but one interval of
Phase II. (Am J Dent 2017;30:305-308).
Clinical significance: This in vitro study evaluated the
fluoride release and subsequent re-release of fluoride following a topical
fluoride treatment to analyze if the materials were truly bioactive. The
results indicate the bioactive material does uptake fluoride and re-release it
which could offer inhibition to caries at restoration margins.
Mail: Dr. Kevin J. Donly, Department
of Developmental Dentistry, School of Dentistry, University of Texas Health
Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229,
USA. E-mail: donly@uthscsa.edu
An induced extrinsic tooth stain prevention model to
investigate whitening
Michael W.J. Dodds, bds, phd, Minmin Tian,
phd, Lilian
Ramirez, bs, Jeffery L. Milleman,
dds, mpa,
Kimberly R. Milleman, rdh,
bsed, ms & Howard M. Proskin, phd
Abstract: Purpose: To establish an accelerated clinical test method to
evaluate the effectiveness of sugar-free gums in prevention of the formation of
extrinsic stains when chewed over a 2-week period in conjunction with daily
tooth brushing. A secondary objective was to compare three methods for
measuring extrinsic stain. Methods: 25 healthy adult volunteers were enrolled in a single center, examiner blind, randomized 4-way crossover clinical study. Starting with a
stain-free baseline, subjects rinsed five times daily with freshly brewed black
tea, followed either by chewing one of three different gums for 12 minutes or
not chewing (negative control). Extrinsic stain was measured at 1 and 2 weeks
by modified Lobene Stain Index (MLSI), digital imaging, and a Vita EasyShade
spectrophotometer. Results: At 2
weeks, MLSI scores showed a statistically significant mean reduction of 43% or
greater versus no-gum control for all three gum treatments. Digital image
analysis and Vita EasyShade measurement showed reductions of yellowness
(measured by difference in ∆b* values between the three gums and the
non-gum control treatment) ranging from 0.28 to 0.34 and 3.52 to 4.18 ∆b*
units, respectively, for subjects using the chewing gums versus no-gum control
(P< 0.05) after 2 weeks. This clinical study demonstrated that sugar-free
gum can effectively reduce new stain formation along with daily tooth brushing
in as little as 2 weeks when used in conjunction with tea rinsing to help
promote more rapid stain formation. All three test methods confirmed the
results, albeit with different levels of statistical significance. A minor
modification of gum base polymer, or change of flavors, did not significantly
impact the prevention of new stain formation. (Am J Dent 2017;30:309-315).
Clinical significance: Regular
consumption of sugar-free chewing gum helps prevent extrinsic dental stain
accumulation and provides a simple and enjoyable means for consumers to
maintain their natural tooth color.
Mail: Dr.
Michael W.J. Dodds, The William Wrigley Jr. Co., 1132
West Blackhawk St., Chicago, IL 60642, USA. E-mail: michael.dodds@wrigley.com
Effects of cigarette smoking on color stability of
dental resin composites
Xiaoyi Zhao, dds, phd, Filippo Zanetti, phd, Shoaib
Majeed, ms, Jie Pan, dds, phd, Hans
Malmstrom, dds,
Abstract: Purpose: To study the effects of cigarette smoke (CS) on the discoloration of
dental resin composite compared with the aerosol from a heat-not-burn tobacco
product, the Tobacco Heating System 2.2 (THS2.2). Methods: A total of 60 discs were prepared from three commercial
resin composites: Durafill VS (DVS), Filtek Supreme Ultra (FSU) and Tetric
EvoCeram BulkFill (TEC). Twenty discs of each composite were divided into two
groups and exposed to CS from 20 reference cigarettes (3R4F) or aerosol from 20
THS2.2 tobacco sticks per day for 3 weeks. Color, gloss and surface roughness
of the composite discs were measured at baseline and after exposure and
brushing with toothpaste at 1, 2 and 3 weeks. Results: Color differences from the baseline (ΔE) were on
average 27.1 (±3.6) in 3R4F and 3.9 (±1.5) in the THS2.2 group after 3 weeks of
exposure (P< 0.0001). TEC (30.4±1.4 and FSU (28.0 ±2.5) exhibited more
discoloration than DVS (23.0±1.2) in the 3R4F group (P< 0.0001). FSU (2.6±0.5)
showed significantly less discoloration than TEC (5.3±1.5) in the THS2.2 group
(P< 0.0001). Surface roughness of resin composites was not affected by
either CS or THS2.2 aerosol, while surface gloss increased in the composite
discs with more severe discoloration. (Am
J Dent 2017;30:316-322).
Clinical significance: Cigarette smoke caused
significant discoloration of dental composite resins. Reducing or eliminating
the deposits derived from combustion of tobacco has the potential to minimize
the impact of smoking on the color of composite resin restorations.
Mail: Dr. Yanfang Ren, University
of Rochester Eastman Institute for Oral Health, 625 Elmwood Ave., Rochester, NY
14620, USA. E-mail: Yanfang_ren@urmc.rochester.edu
Effect of various teas on color stability of resin
composites
Gül Dinç Ata, dds, phd, Osman Gokay, dds, phd, Arzu
Müjdeci, dds, phd, Tugba
Congara Kivrak, dr
& Armin Mokhtari Tavana, dr
Abstract: Purpose: To investigate the effect of
various teas on color stability of resin composites. Methods: Two methacrylate-based (Arabesk Top, Grandio) and a
silorane-based (Filtek Silorane) resin composites were used. 110 cylindrical
samples of each resin composite were prepared (2 mm thickness and 8 mm
diameter), polished and stored in distilled water (37°C for 24 hours). They
were randomly divided into 11 groups (n= 10) and color measurements were taken.
Then the samples were immersed in tap water (control), a black tea, a green tea
or one of the eight herbal-fruit teas (37°C for 1 week) and subsequently
subjected to the final color measurements. The color change of samples
(ΔE*) was calculated, data were subjected to two-way ANOVA and Tukey’s HSD
tests. Results: Teas, resin composites
and their interactions were significant (P= 0.000). All the teas and control
caused color changes in all three resin composites. Rosehip tea caused the most
color changes, while tap water showed the least in all resin composites.
Arabesk Top had the most staining potential in all the teas and control,
whereas Filtek Silorane was the most stain resistant except Grandio immersed in
sage tea. Color stability of all resin composites used were affected from both structure of resin materials and constituents of teas used.
All resin composites were susceptible to staining by all teas especially
rosehip tea. Arabesk Top composite showed the greatest color susceptibility in
all teas and Filtek Silorane the least with one exception. (Am J Dent 2017;30:323-328).
Clinical significance: Color of resin composites can be
negatively affected from teas consumed. Clinicians should advise patients that
drinking different kind of teas could intensify surface staining of resin based
restorations.
Mail: Dr. Gül Dínc Ata, Department
of Restorative Dentistry, Faculty of Dentistry, Adnan Menderes University,
Aydın, TR 09100, Turkey. E-mail dtguldinc@gmail.com
Efficacy of different protocols for at-home
bleaching:
Iria López Darriba, dds, Lourdes
Novoa, dds & Víctor
Alonso de la Peña, phd, md, dds
Abstract: Purpose: To evaluate the efficacy of
two products used for at-home bleaching with different application times. Methods: 80 participants were enrolled
and divided into four groups, (1) 10% carbamide peroxide 1 hour a day; (2) 10%
carbamide peroxide overnight; (3) 7.5% hydrogen peroxide 1 hour a day; and (4)
7.5% hydrogen peroxide overnight. The duration of treatment was 14 days. Color
measurement was performed using a dental spectrophotometer on the right
maxillary central incisor and the canine, at baseline and 2 weeks after.
Participants recorded daily tooth sensitivity. To evaluate the influence of
concentration and time on bleaching results (ΔE) the one-way ANOVA with
Bonferroni post-hoc test and the Student’s t-test were used. Results: Group 2 showed the highest
value of ΔE (ΔE = 10.59 ± 2.68), followed by Group 4 (ΔE = 8.95
± 2.32), Group 1 (ΔE = 8.05 ± 3.86), and Group 3 (ΔE = 7.08 ± 1.99).
There were differences between Groups 2 and 3 (P= 0.001) and between Groups 2
and 1 (P= 0.032). The same product applied overnight was more effective than
applied 1 hour a day (P< 0.05). Different concentrations during the same
application time achieved similar results. The reported tooth sensitivity was
mild. (Am J Dent 2017;30:329-334).
Clinical significance: At-home bleaching is time but not
concentration dependent and its secondary effects depend on the active agent
concentration; therefore, there is no need to use high concentration products.
The most effective protocol is low concentrations (10% carbamide peroxide) with
overnight use.
Mail: Dr. Iria López Darriba.
Department of Surgery and Medical and Surgical Specialties, Faculty of Medicine
and Dentistry, University of Santiago de Compostela, Entrerríos s/n. 15782,
Santiago de Compostela - A Coruña, Spain. E-mail: iria.lopez.darriba@rai.usc.es
Efficacy of an experimental 3% potassium nitrate
mouthwash in providing
Claire Hall, msc, Farzana Sufi, msc & Paul Constantin, msc
Abstract: Purpose: To evaluate the efficacy of an experimental mouthwash
containing 3% potassium nitrate (KNO3) in the relief of dentin
hypersensitivity when used as an adjunct to brushing with fluoride toothpaste
compared with the use of the same toothpaste alone. Methods: This was a randomized, two-treatment, examiner-blind,
parallel-design single-center, 8-week study in healthy subjects with
self-reported and clinically diagnosed dentin hypersensitivity. Subjects were
randomized to receive either fluoride toothpaste plus
3.0% KNO3 mouthwash or the same fluoride toothpaste alone, and
instructed to use their allocated treatment twice daily for the next 8 weeks.
Dentin hypersensitivity was evaluated at baseline and following 4 and 8 weeks
of treatment through assessment of responses to evaporative (air) and tactile
stimuli [measured by the Schiff sensitivity scale/a visual rating scale (VRS)
and tactile threshold, respectively], and using the Dentin Hypersensitivity
Experience Questionnaire (DHEQ; a validated quality-of-life instrument for
dentin hyper-sensitivity). Results: A total of 135 subjects were randomized and all completed the study. Both
treatment groups demonstrated statistically significant improvements in
sensitivity from baseline for each clinical measure of sensitivity (P<
0.0001) at Week 4 and Week 8. The toothpaste plus mouthwash group showed
greater reductions in sensitivity at both timepoints for all clinical measures;
between-treatment differences were only statistically significant for responses
to an evaporative (air) stimulus (Schiff sensitivity score and VRS) at Week 4.
There was evidence of an improvement in dentin hypersensitivity-associated
quality of life as measured by changes from baseline in several DHEQ parameters
for both treatment groups, but there were no statistically significant
differences between treatments. (Am J
Dent 2017;30:335-342).
Clinical significance: Although in the current study
adjunctive use of a 3% KNO3 mouthwash did not provide statistically
significant improvements in dentin hypersensitivity for all clinical measures
at all timepoints compared with use of fluoride toothpaste alone, the
reductions in sensitivity observed in this study are compatible with the
findings of a previous study that showed adjunctive use of a 3% KNO3 mouthwash to be effective in providing relief from dentin hypersensitivity
after 8 weeks’ twice-daily use.
Mail: Farzana Sufi, Clinical
Research (Oral Care), Research & Development, GSK Consumer Healthcare, St
George’s Avenue, Weybridge, Surrey, KT13 0DE, UK. E-mail:
farzana.x.sufi@gsk.com
Effect of instruction, light curing unit, and
location in the mouth
Sara Samaha, dmd, Sapan Bhatt, dmd, Matthew
Finkelman, phd, Aikaterini Papathanasiou, Dmd, dds,
Abstract: Purpose: To determine the amount of energy
(Joules/cm2) delivered by
students to simulated restorations in a patient simulator based on the
restoration location, the curing light unit used, and before vs. after
instruction on how to improve their light curing technique. Methods: 30 dental students “light
cured” two simulated restorations (that were 1-mm deep anterior and 4-mm deep
posterior) using three light-curing units (LCUs): VALO, Bluephase G2, and
Optilux 401. A MARC Patient Simulator was used to measure the irradiance (mW/cm2)
received by the restorations in real-time to calculate the radiant exposure
(J/cm2) delivered during a 20-second exposure. At first, students
were asked to use the light curing technique that they had been previously
taught. They were then given 5 minutes of additional verbal instructions and a
practical demonstration on proper curing technique using the patient simulator.
They then light cured the restorations again. Based on a literature review, 16
J/cm2 was considered the minimum acceptable radiant exposure. Results: Before receiving instruction
using the simulator, some students delivered as little as 4 J/cm2 to
the restoration. A mixed model test determined that the radiant exposure
delivered to the anterior restoration was significantly greater than that
delivered to the posterior restoration (P< 0.001). Additionally, when the
locations were compared for each LCU individually, a paired t-test determined
that before the students received the additional instruction, the anterior
restoration received a significantly greater radiant exposure than the
posterior restoration, for all three LCUs. Further paired t-tests and Wilcoxon
signed-rank tests determined that after instruction, the radiant exposure improved
significantly at both the anterior and posterior locations, for all three LCUs.
The Bluephase G2 and the VALO each individually delivered 45% more radiant
exposure than the Optilux 401 (P< 0.001 for both). The Bluephase G2 and VALO
lights delivered similar mean radiant exposures (25.4 J/cm2 and 25.7
J/cm2, respectively). This difference was not significant. Depending
on the light unit used, at the posterior location, there was a 24 to a 52%
increase in the mean radiant exposure that was delivered after instruction
compared to before instruction. (Am J Dent 2017;30:343-349).
Clinical significance: Prior to
using the patient simulator, students and their instructors thought that the
students were delivering an adequate amount of energy when light curing. This
was not always the case. The location of the restoration, the curing light
output, its size and shape and how it is used all affected the amount of energy
delivered to a restoration. Dental professionals and educators should be aware
that appropriate training can improve the amount of energy delivered, and that
restorations in posterior teeth will require longer exposure times than those
in anterior teeth.
Mail: Dr. Aikaterini
Papathanasiou, School of Dental Medicine, Tufts University, 1 Kneeland Street,
DHS-221, Boston, MA 02111, USA. E-mail: aikaterini.papathanasiou@tufts.edu
Phosphate buffer-stabilized 0.1% chlorine dioxide
oral rinse
Srinivas Rao Myneni Venkatasatya, dds,
phd, Howard H. Wang, dds, mba, mph,
ms, Swetha Alluri, bs
Abstract: Purpose: This is a review
of the literature on nonsurgical treatment of non-healing medication related
osteonecrosis of the jaw (MRONJ) utilizing a phosphate buffer-stabilized 0.1%
chlorine dioxide mouthrinse. Methods: A literature search in PubMed revealed only six case reports. MRONJ lesion site
description, patient’s medication history, the healing time, and the MRONJ
treatment protocol followed by those authors were recorded. Additional
literature review of the scientific mechanism, risks and benefits, safety and
efficacy of the phosphate buffer-stabilized 0.1% chlorine dioxide mouthrinse was
also performed and discussed. Results: Many of the authors of the published case reports utilized 0.12% chlorhexidine
as the initial mouthrinse, but the lesions did not decrease in size. After
switching to a phosphate buffer-stabilized 0.1% chlorine dioxide mouthrinse for a duration ranging from 1-12 months, there was
complete healing of the MRONJ lesions in all of the cases. The phosphate
buffer-stabilized 0.1% chlorine dioxide mouthrinse can be helpful in the
management of active MRONJ lesions as well as the prevention of recurrent MRONJ
lesions in the susceptible patient population. (Am J Dent 2017;30:350-352).
Clinical significance: This literature review supports
the use of phosphate buffer-stabilized 0.1% chlorine dioxide mouthrinse in the
management of MRONJ lesions either as a first line of therapy or after 0.12%
chlorhexidine had not been effective.
Mail: Dr. Srinivas Rao Myneni Venkatasatya, Dept. of Periodontology, Stony Brook University, 108 Rockland Hall, Stony Brook, New York, USA. E-mail: Srinivas.mynenivenkatasatya@stonybrookmedicine.edu
