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February 2017Abstracts
Effect of CAD/CAM glass fiber post-core on cement micromorphology
Rogério Goulart da Costa, dds, ms, Andrea Freire, dds, ms, phd,
Abstract: Purpose: To investigate the fracture
resistance of weakened roots restored with prefabricated or CAD/ CAM-customized
posts and cores as well as the thickness of the cement film and the presence of
voids in the cement. Methods: The
roots of 40 human premolars were weakened by removing internal dentin with a
diamond bur (2.5 mm in the coronal third and 1.5 mm in the apical third) and restored with prefabricated posts (PPs)
or customized posts (CPs) with or without a zirconia crown (n= 10). Posts and crowns were cemented with
resin cement. Microtomography was used to determine
the thickness of the cement film and whether voids were present. After fatigue
testing (1 million cycles, 50 N, 5 Hz, 36.5ºC), the specimens underwent
compression testing with an oblique load (30º, 1 mm/minute) and fracture
strengths were recorded (N). Fracture strength and film thickness were analyzed
with ANOVA and the Games-Howell test; the variable presence of voids was
analyzed with the Mann-Whitney test (α= 5%). Results: Mean fracture strengths varied between 640.4 and 792.9 N
and did not differ significantly between groups. The CP group had a thinner
cement film and fewer voids than the PP group. There was a positive,
statistically significant correlation (Spearman, R=0.488, P= 0.029) between
these variables. (Am J Dent 2017;30:3-8).
Clinical significance: CAD/CAM-manufactured glass-fiber
posts and cores do not affect the fracture strength of flared root canals or
cause catastrophic failure of the root when used with zirconia crowns.
Mail: Dr. Rodrigo Nunes Rached, PUCPR (Dentistry), Rua Imaculada Conceição, 1155, Curitiba, PR, Brazil,
80215-901. E-mail: r.rached@pucpr.br
Influence of extremely high irradiances on the
micromechanical properties
Zeynep Bilge Kutuk, dds, phd, Sevil Gurgan, dds, phd, Reinhard Hickel, dds, phd & Nicoleta Ilie, dipl-eng, phd
Abstract: Purpose: To investigate in vitro the
effect of extremely high irradiance light-emitting diode (LED) light curing
units (LCU) with different exposure distances and curing modes on the
micromechanical properties of a nano hybrid resin
based composite. Methods: 72 resin
based composite (RBC) (Kalore) specimens with 2 mm
thickness were cured using two high irradiance LED LCUs (Bluephase 20i and FlashMax P3) at 0 and 7 mm exposure
distances. The curing conditions were: a) Bluephase 20i – 10 seconds – High power; b) Bluephase 20i – 15 seconds
– High power; c) Bluephase 20i – 5 seconds – Turbo;
d) Bluephase 20i – 15 seconds – Soft start; e) FlashMax P3 – 4 mm tip cover – 3 seconds; f) FlashMax P3 – without tip cover – 3 seconds. The incident
and transmitted irradiance and radiant exposure were evaluated in real time
during curing, with a radiometer (MARC Resin Calibrator). The micromechanical
properties (Vickers hardness, HV and indentation modulus, E) were measured with
an automatic universal hardness indenter after storing specimens for 24 hours
in distilled water. Data were analyzed with one- and two-way ANOVA tests
followed by Tukey test and partial eta-square
statistics (α= 0.05). Results: For both LCUs, incident irradiance decreased progressively with increased
exposure distance, reaching at 7 mm exposure distance less than 50% of the
value measured when the LCU was applied directly on specimen’s surface. In
descending order of strength of their effects, the parameters incident
irradiance (HV; ηP²=0.828, E; 0.693), LCU (HV, 0.257, E, 0.043) and
exposure distance (HV, 0.031, E, 0.028) were significant factors affecting HV
and E (P < 0.05). The localized radiant exposure (the incident and
transmitted) as well as the position of HV and E measurements (top-bottom of
the specimen) were additional factors affecting significantly only HV (P <
0.05), but not E (P > 0.05). (Am J
Dent 2017;30:9-15).
Clinical significance: Extremely high irradiances were
less efficient in adequate curing of the analyzed nano hybrid composite. Using a protection tip, as clinically indicated, reduces the
irradiance of FlashMax P3 from 7,681.7 (160.53) mW/cm2 to 3052.5 (71.61) mW/cm2.
Mail: Dr. Zeynep Bilge Kutuk, Department of Restorative Dentistry, Hacettepe University, School of Dentistry, Sihhiye, Ankara, 06100, Ankara, Turkey. E-mail: dt.zeynepbilge@gmail.com
Determination of polymerization shrinkage of different
composites
Inga Rullmann, dds, Michael Patyna, dds, Bram
Janssen, dds,
Abstract: Purpose: To investigate the
polymerization shrinkage stress of different low viscous bulk composites (SDR,
Venus Bulk Fill, X-tra Base, Filtek Bulk Fill) in comparison to a conventional flowable composite (Filtek Supreme XTE Flow) and to high
viscous bulk and conventional composites (Filtek Supreme XTE, GrandioSO, Tetric EvoCeram, Tetric EvoCeram BulkFill, Venus Diamond,
Venus Pearl), as well as to an experimental composite (Ormocer)
and a sonic-activated bulk fill composite (Sonicfill),
by means of photoelastic investigation. Methods: To ensure bonding of the resin
composite, cylindrical cavities (Ø 4mm) in araldite B epoxide resin plates (40 × 40 × 4 mm3) were pre-treated with the Rocatec system. Embedded in araldite plates, six resin
composite specimens of each material were exposed for 60 seconds from one side
(Translux Power Blue, 1,000 mW/cm2). The samples were stored,
light-protected and dry (23°C). Polymerization shrinkage stress data (MPa) were calculated 15 minutes, 1 and 24 hours after light
exposure, based on the diameter of the isochromatic curves of first order, obtained from araldite plates. Statistical analysis was
performed with the Wilcoxon-test and Bonferroni correction (P< 0.0006). Results: After 15 minutes/1 hour, the mean polymerization stress
values calculated were: for SDR 4.4 ± 0.1/4.4 ± 0.2 MPa;
Venus Bulk Fill 4.8 ± 0.3/4.9 ± 0.3 MPa; X-tra Base 6.5 ± 0.3/6.7 ± 0.3 MPa; Filtek Bulk Fill 4.9 ± 0.3/4.9 ± 0.3 MPa; Filtek Supreme XTE Flow 8.0
± 0.3/8.2 ± 0.2 MPa; Filtek Supreme XTE 7.1 ± 0.1/7.4 ± 0.2 MPa; GrandioSO 6.3 ± 0.4/6.3 ± 0.3 MPa; Tetric EvoCeram 4.5 ±
0.1/4.6 ± 0.1 MPa; Tetric EvoCeram BulkFill 4.9 ± 0.2/5.0 ±
0.3 MPa; Venus Diamond 3.7 ± 0.3/3.8 ± 0.3 MPa; Venus Pearl 3.9 ± 0.2/4.0 ± 0.2 MPa, Sonicfill 5.4 ± 0.2/5.6 ± 0.3 MPa;
and Ormocer (experimental) 4.1 ± 0.2/4.3 ± 0.2 MPa. After 24 hours, the following mean stress values were
obtained: SDR 4.7 ± 0.2 MPa; Venus Bulk Fill 5.1 ±
0.2 MPa; X-tra Base 7.2 ±
0.4 MPa; Filtek Bulk Fill
5.3 ± 0.3 MPa; Filtek Supreme XTE Flow 8.7 ± 0.3 MPa; Filtek Supreme XTE 7.9 ± 0.2 MPa; GrandioSO 7.0 ± 0.4 MPa; Tetric EvoCeram 4.9 ± 0.1 MPa; Tetric EvoCeram BulkFill 5.4 ± 0.3 MPa; Venus
Diamond 4.5 ± 0.3 MPa; Venus Pearl 4.5 ± 0.3 MPa, Sonicfill 5.8 ± 0.2 MPa and Ormocer (experimental)
4.5 ± 0.2 MPa. The new and experimental resin
composites showed significantly less polymerization shrinkage stress than the
conventional resin composite (Filtek Supreme XTE). (Am J Dent 2017;30:16-22).
Clinical significance: Resin composite restoratives
differ in their polymerization shrinkage stress development, independent of
their viscosity. Some low viscosity bulkfill-restoratives
generate less shrinkage stress compared to other conventional or
bulk-restoratives. Practitioners should yield to the potential effect of
shrinkage stress development, because this might affect marginal integrity in
the clinical performance.
Mail: Michael Patyna, Department
for Operative Dentistry, University Medical Center of the Johannes Gutenberg
University Mainz, Augustusplatz 2, D-55131 Mainz, Germany. E-mail: michael.patyna@unimedizin-mainz.de
Effect of conventional and contemporary disinfectant
techniques
Mansour Rismanchian, dds,
ms, Saeid Nosouhian, dds, ms, Mohammad Shahabouee, dds, ms, Amin Davoudi, dds
Abstract: Purpose: To evaluate the antiseptic
properties of five different disinfectant techniques on three different peri-implantitis (PI) associated biofilms. Methods: 90 implant titanium disks,
with the same thickness and diameter, were prepared and randomly divided into
18 groups (n = 5) based on the microbiota strains (S. aureus, S. epidermidis and C. albicans)
and using the following disinfectant techniques: soft laser therapy,
photodynamic therapy (PDT), 0.12% NaOCl, 0.2% chlorhexidine,
3% H2O2, and control groups. After forming a protein
layer on disk surfaces, the specimens were exposed to the microbial
suspensions. After decontamination according to designated techniques, 2% Trypsin protease was administered to isolate the surviving
microorganisms. Muller Hinton agar culture was used for microbiota growth. After 48-hour incubation, the standard colony forming unit (CFU) was
assayed and the collected data were analyzed by Kruskal-Wallis
and Mann-Whitney tests at a significance level of 0.05. Results: The highest amount of CFU/ml values was shown by C. albicans, which
was subjected to PDT (25.12 ± 30.23). The least disinfecting efficacy on S. epidermidis was demonstrated by the laser group (all P-values ≤ 0.01). Nevertheless,
all of the groups exhibited significant differences with the control groups
(all P-values < 0.01). (Am J Dent 2017;30:23-26).
Clinical significance: None of the studied disinfectant
techniques had the highest lethal effects on all of the tested microbiotas. Therefore, a combination of these disinfectant
techniques, for instance PDT + 3% H2O2 or 0.2% chlorhexidine, is recommended.
Mail: Dr. Saeid Nosouhian, Hezar Jarib St, Dental Implants Research Center, Isfahan
University of Medical Sciences, Isfahan, Iran. E-mail: nosouhian@dnt.mui.ac.ir
Efficacy of an experimental 3% potassium nitrate
mouthwash in providing
Claire Hall, msc, Farzana Sufi, msc, Nan
Wang, phd & Chhaju Ram Goyal, bdsc
Abstract: Purpose: To evaluate the efficacy of an experimental mouthwash
containing 3% potassium nitrate (KNO3) in relieving dentin
hypersensitivity when used as an adjunct to brushing with fluoride toothpaste
compared with use of the same toothpaste alone. Methods: This was one of three randomized, two-treatment,
examiner-blind, parallel-design, single-site, 8-week studies in healthy
subjects with self-reported and clinically diagnosed dentin hypersensitivity.
Subjects were randomized to receive either fluoride toothpaste plus 3% 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 216 subjects were randomized and 214 completed the study. Both
treatment groups demonstrated statistically significant reductions from
baseline for each clinical measure of sensitivity (P≤ 0.01) at Weeks 4
and 8. Use of the 3% KNO3 mouthwash after brushing with fluoride
toothpaste resulted in statistically significantly greater reductions in
sensitivity to an evaporative (air) stimulus (mean Schiff score and mean VRS,
P< 0.001; primary objective mean Schiff score at Week 8, P< 0.0001) and
statistically significantly higher tactile threshold (P< 0.001) at Weeks 4
and 8 compared with toothpaste alone. The DHEQ responses reflected the clinical
outcomes for several parameters, indicating a significant improvement in oral
health-related quality of life after 8 weeks’ use of the 3% KNO3 mouthwash. (Am J Dent 2017;30:27-34).
Clinical significance: The results of this study
suggest that daily use of a 3% KNO3 mouthwash as an adjunct to
brushing with fluoride toothpaste provides clinically relevant improvements in
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
Role of tyrosol on Candida albicans, Candida glabrata and Streptococcus mutans
Douglas Roberto Monteiro, phd, Laís Salomão Arias, msc, Renan Aparecido Fernandes, msc,
Abstract: Purpose: To assess the effect of tyrosol on the production of hydrolytic enzymes (by Candida biofilm cells) and acid (by Streptococcus mutans biofilms), as well as to quantify single and mixed biofilms of these species formed on acrylic resin (AR) and hydroxyapatite (HA). Methods: Candida and S. mutans biofilms were formed on AR and HA in the presence of tyrosol during 48 hours. Next, acid proteinase, phospholipase and hemolytic activities of Candida biofilm cells were determined,
while acid production by S. mutans biofilms was assessed
by pH determination. The effect of tyrosol on mature biofilms (96 hours) was evaluated through quantification of
total biomass, metabolic activity, number of
colony-forming units and composition of biofilms’
extracellular matrix. Data were analyzed by one- and two-way ANOVA, followed by Tukey’s and Holm-Sidak’s tests (α = 0.05). Results: Treatments with tyrosol were not able to
significantly reduce hydrolytic enzymes and acid production by Candida and S. mutans. Tyrosol only significantly reduced the metabolic activity of single biofilms of Candida species. (Am J Dent 2017;30:35-39).
Clinical significance: Tyrosol on its own had a limited efficacy against single and mixed-species oral biofilms. Its use as an alternative antimicrobial for
topical therapies still demands more investigation.
Mail: Dr. Douglas Roberto
Monteiro, Universidade do Oeste Paulista (UNOESTE), Dental School of Presidente Prudente, Department of Prosthodontics, Rua José Bongiovani 700,
19050-920 Presidente Prudente,
SP, Brazil. E-mail: douglasrmonteiro@hotmail.com
Influence of manual and
power toothbrushes on clinical and microbiological
Gerhard Schmalz, dr med dent, Marion
Müller, dr med dent, Jan Schmickler, dr med dent,
Abstract: Purpose: This randomized clinical study
compared the influence of manual and power toothbrushes on clinical and
microbiological findings in initial treatment of periodontitis. Methods: A total of 72 participants
with a mean age of 55.7 years were randomly assigned to three groups (n= 24):
oscillating-rotating (OR), sonic-active (SA) and manual toothbrush (MTB). At
baseline, after 4 weeks and after 12 weeks, the following parameters were
assessed: modified Quigley-Hein-Index (QHI), papilla bleeding index (PBI),
periodontal pocket depth (PPD), bleeding on probing (BOP) and recession. For
microbiological analysis (PCR) of 11 periodontal pathogenic bacteria, samples
of sulcular fluid were taken from the deepest
pockets. Statistical analysis was performed using ANOVA, with the level of
significance set at α= 5%. Results: All clinical parameters: PBI, modified QHI, PPD, BOP and recession showed an
improvement after 12 weeks compared to baseline, regardless of which toothbrush
system was used. Regarding PBI, the SA group showed significantly greater
improvement compared to OR and MTB (P< 0.01). In plaque removal (QHI) only
OR was significantly more effective than MTB (P= 0.01). Periodontal parameters
showed a significantly higher reduction of PPD for SA compared to MTB and MTB
compared to OR (P< 0.05), while for BOP only a significantly higher
reduction in SA compared to OR was detected (P= 0.01) Microbiological analysis
showed an improvement in prevalence of several bacteria without significant
differences between groups. (Am J Dent 2017;30:40-46).
Clinical significance: Patients
might benefit from powered TB systems, especially in initial treatment of
periodontitis.
Mail: PD Dr. Dirk Ziebolz, M.Sc.,
Dept. of Cariology, Endodontology and Periodontology, University Medical Center Leipzig, Liebigstr. 10-14, D 04103 Leipzig,
Germany. E-mail:
dirk.ziebolz@medizin.uni-leipzig.de
Fluoride release and re-release from various esthetic
restorative materials
Shahad Abudawood, bds, ms & Kevin J. Donly, dds,
ms
Abstract: Purpose: To measure the amount of
fluoride release and re-release after re-charge from two commonly used esthetic
restorative materials and compare it to a new experimental material. Methods: 30 standardized disc-shaped
specimens were fabricated using resin-based composite (Z100), resin-modified
glass-ionomer cement (Vitremer) and a new
experimental material which is a self-curing resin-based composite with light
curing option. 10 specimens were made from each material. The specimens of each
group were immersed separately in 10 ml distilled water. Fluoride release was
measured after 1, 7, 14 and 30 days using a fluoride-specific ion electrode and
an ion-analyzer. The specimens were then exposed to 2.0% neutral sodium
fluoride foam (0.9% fluoride ion). The amount of fluoride re-released was
measured at Days 1, 7, 14 and 30. Results: An ANOVA indicated a
statically significant variance among the groups (P< 0.001). The
experimental group demonstrated significantly less fluoride release at Day 1
compared to Day 31 (first day after 2% sodium fluoride application). At Days 7,
14 and 30 there was significantly more fluoride release than Day 7, 14 and 30
after the topical fluoride application (P< 0.001). There was significantly
more fluoride release from Vitremer than the
experimental material at Days 1 and 7. However, similar release was observed at
Days 14 and 30 for Vitremer and experimental
material, but not for Z100. Both Vitremer and the
experimental material showed significantly more release of fluoride compared to
Z100 at all time points. (Am J Dent 2017;30:47-51).
Clinical significance: This study demonstrates that the
new experimental material released fluoride, re-charged and re-released
fluoride at a level comparable to Vitremer but more
than Z100.
Mail: Ms. Shahad Abudawood, 8210 Floyd Curl Drive MSc 8118, San Antonio, TX 78229-3900, USA. E-mail: Abudawood@livemail.uthscsa.edu
Effects of atmospheric non-thermal argon/oxygen
plasma
Tianshuang Liu, dds, ms, Linfeng Wu, ms, phd, Jegdish P. Babu, ms, msc, phd, Timothy
L. Hottel, dds, ms, mba,
Abstract: Purpose: To evaluate the bactericidal effects of atmospheric
non-thermal argon/oxygen plasma on in vitro oral biofilms constructed from S. mutans and/or S. sanguinis,
and the influence of the plasma on the virulence properties of A. oris. Methods: In vitro oral biofilms were constructed in the wells of 48-well plates
from S. mutans and/or S. sanguinis.
The wells containing constructed biofilms and various
amounts of phosphate-buffered saline (PBS) were treated with non-thermal
argon/oxygen plasma brush for 2 minutes. The methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay and Live/Dead assay were used to evaluate the viability of biofilms in those wells after the plasma treatments.
Meanwhile, A. oris suspensions were treated with the plasma and then evaluated for their virulence
properties by measuring the hydrophobicity and
co-aggregation capability of treated A. oris. Results: The
MTT assay showed that exposure to non-thermal plasma for 2 minutes significantly
reduced the viability of bacteria in both single-species and two-species biofilms of S. mutans and S. sanguinis with the reductions of up to 99%. Meanwhile,
plasma treatment also altered the hydrophobicity of A. oris, and
reduced their capability to co-aggregate with S. sanguinis. (Am J Dent 2017;30:52-56).
Clinical significance: The results from this study
demonstrated that atmospheric non-thermal argon/oxygen plasma could effectively deactivate oral bacteria biofilm
by decreasing bacterial viability as well as reducing their hydrophobicity and co-aggregation capability.
Mail: Dr.
Liang Hong, College of Dentistry, University of Tennessee Health Science
Center, 875 Union Avenue, Memphis, TN 38163, USA. E-mail: lhong2@uthsc.edu
