Surface
properties of resin-based composite materials and biofilm formation:
Gloria Cazzaniga, dds, Marco Ottobelli, dds, Andrei Ionescu, dds, phd, Franklin Garcia-Godoy, dds,
ms, phd, phd & Eugenio Brambilla, dds
Abstract: Purpose: To evaluate
the state of art on the relations between surface properties (surface
roughness, topography, surface free energy and chemistry) of resin-based
composite materials and microbial adhesion and biofilm formation. Methods: An electronic search using
Scopus and PubMed (until May 2015) was conducted applying the following search
items: “Plaque OR Biofilm AND Surface chemistry”, “Plaque OR Biofilm AND
Surface-free energy”, “Plaque OR Biofilm AND Roughness”, “Surface
characteristics AND Composites”, “Biofilm AND Surface characteristics”. Results: Surface properties of
resin-based composite materials as well as surface treatments can strongly
affect bacterial adhesion and biofilm formation, although the “ideal” surface
features have not been identified yet. Moreover, investigations highlighted
that cariogenic biofilm formation may alter materials’ surface properties, thus
encouraging bacterial adhesion and biofilm formation, starting a “vicious
cycle” which might compromise restoration longevity. (Am J Dent 2015;28:311-320).
Clinical
significance: The
understanding of the complex interactions between oral microorganisms and
resin-based composite materials could be of great importance to guide the
development of new materials able to modulate microbial adhesion and biofilm
formation.
Mail: Dr.
Gloria Cazzaniga, I.R.C.C.S. Galeazzi Institute, Department of Biomedical,
Surgical and Dental Sciences, University of Milan, Via Pascal 36, Milan, Italy. E-mail: gloria.cazzaniga@yahoo.it
Adhesive sealing of dentin surfaces in
vitro: A review
Manar M. Abu Nawareg, bds,
msc, phd, Ahmed Z. Zidan, bds, msc, phd, Jianfeng Zhou, dds, phd, Ayaka Chiba,
bds, Jungi Tagami, dds, phd & David
H. Pashley, dmd, phd
Abstract: Purpose: This review
describes the evolution of the use of dental adhesives to form a tight seal of
freshly prepared dentin to protect the pulp from bacterial products, during the
time between crown preparation and final cementation of full crowns. The
evolution of these “immediate dentin sealants” follows the evolution of dental
adhesives, in general. That is, they began with multiple-step, etch-and-rinse
adhesives, and then switched to the use of simplified adhesives. Methods: Literature was reviewed for
evidence that bacteria or bacterial products diffusing across dentin can
irritate pulpal tissues before and after smear layer removal. Smear layers can
be solubilized by plaque organisms within 7-10 days if they are directly
exposed to oral fluids. It is likely that smear layers covered by temporary
restorations may last more than 1 month. As long as smear layers remain in
place, they can partially seal dentin. Thus, many in vitro studies evaluating
the sealing ability of adhesive resins use smear layer-covered dentin as a
reference condition. Surprisingly, many
adhesives do not seal dentin as well as do smear layers. Results: Both in vitro and in vivo studies show that resin-covered
dentin allows dentin fluid to cross polymerized resins. The use of simplified
single bottle adhesives to seal dentin was a step backwards. Currently, most
authorities use either 3-step adhesives such as Scotchbond Multi-Purpose or
OptiBond FL or two-step
self-etching primer adhesives, such as Clearfil SE, Unifil Bond or AdheSE. (Am J Dent 2015;28:321-332).
Clinical
significance: Although
newly developed adhesive resins have attempted to improve dentin sealing, many
such attempts failed. The use of two-step self-etching
primer adhesives that combine the use of an acidic primer with a solvent-free
adhesive layer provide excellent sealing in vitro. The use of three-step,
etch-and-rinse adhesive systems like Scotchbond Multi-Purpose or OptiBond FL,
that also use solvent-free adhesives, seal dentin very well, in vitro.
Mail:
Dr. David H. Pashley, Department of Oral Biology, College of Dental Medicine,
Georgia Regents University, Augusta, GA, 30912, USA. E-mail: dpashley@gru.edu
Dentin wear after simulated toothbrushing with water, a liquid dentifrice
Youngjune Jang,
dds, Jung-Joon Ihm, phd, Su-Jin Baik, Kyung-Jin Yoo, Da-Hyun Jang,
Abstract: Purpose: To investigate the influence of dentifrices with and
without abrasives on the wear and surface topography of human dentin following
simulated toothbrushing in vitro. Methods: 24 dentin specimens were prepared and randomly allocated to a liquid dentifrice
(Garglin Gum-Guard), conventional dentifrice (333 Clinic Total Care), and
control (distilled water) groups. Specimens were subjected to simulated toothbrushing
of 50,000 repeated strokes under a 150 g-load. The dentin surface was profiled
in each specimen using a profilometer before and after toothbrushing. The mean
surface roughness (Ra) of the specimens was calculated and compared by one-way
ANOVA and Tukey's post-hoc test (α= 0.05). The dentin surfaces were
further examined by scanning electron microscopy (SEM). Results: The Ra values were similar between the liquid dentifrice
and control groups (P> 0.05), and was significantly higher in the
conventional dentifrice group (P< 0.001). On SEM examination, patent dentin
tubules were observed in the conventional dentifrice and liquid dentifrice
groups, but were not observed in the control group. (Am J Dent 2015;28:333-336).
Clinical significance: Liquid dentifrice reduced dentin
wear caused by toothbrushing compared to conventional dentifrice. However, for
dentin hypersensitivity, liquid dentifrice requires further validation because
both conventional and liquid dentifrices caused patent dentin tubules on the worn
dentin surface.
Mail: Dr. Deog-Gyu Seo,
Department of Conservative Dentistry and Dental Research Institute, School of
Dentistry, Seoul National University, 101 Daehak-ro, Jongno-gu, Seoul, Korea.
E-mail: dgseo@snu.ac.kr
Evaluation of two
disinfection/sterilization methods on silicon rubber-based
Vânia A.
Lacerda, ms, Leandro O. Pereira, ms, Raphael Hirata Junior, dds, ms, scd & Cesar R. Perez, dds, ms, scd
Abstract: Purpose: To evaluate the effectiveness of
disinfection/sterilization methods and their effects on polishing capacity,
micromorphology, and composition of two different composite finishing and
polishing instruments. Methods: Two
brands of finishing and polishing instruments (Jiffy and Optimize), were
analyzed. For the antimicrobial test, 60 points (30 of each brand) were used
for polishing composite restorations and submitted to three different groups of
disinfection/sterilization methods: none (control), autoclaving, and immersion
in peracetic acid for 60 minutes. The in vitro tests were performed to evaluate
the polishing performance on resin composite disks (Amelogen) using a 3D
scanner (Talyscan) and to evaluate the effects on the points’ surface
composition (XRF) and micromorphology (MEV) after completing a polishing and
sterilizing routine five times. Results: Both sterilization/disinfection methods were efficient against oral
cultivable organisms and no deleterious modification was observed to point
surface. (Am J Dent 2015;28:337-341).
Clinical significance: The analyzed polishing
instruments (Jiffy and Optimize) were sterilized/disinfected with an autoclave
or peracetic acid at least five times without changing the performance,
superficial composition, or morphological aspects. The peracetic acid proved to
be an excellent choice as a disinfecting agent but should not be indicated for
sterilization. In this case, the autoclave remains the ideal option.
Mail:
Dr. Cesar R. Perez, R. São Francisco Xavier, 524 Maracanã, Rio de Janeiro, RJ, CEP
20550-900, Brazil. E-mail: cesarperez@superig.com.br
Efficacy of different “in-office” desensitizing
treatment methods:
Renata De Cássia Gomes Camacho, dds, Giovana Lecio Miranda,
dds, Fábio Tonasso Oliveira,
Abstract: Purpose: To evaluate, in vitro, the obliteration of dentin
tubules promoted by different desensitizing methods, before and after pH
cycling. Methods: Human dentin
blocks of 4×4 mm were randomly divided into: control group (n= 20): no
treatment; Group GH (n= 20): surface treatment with a solution containing
glutaraldehyde (5.1%), HEMA (36.1%), sodium fluoride (NaF), and deionized
water; Group NP (n= 20): surface treatment with a calcium phosphate gel
containing nanostructured hydroxyapatite crystals, NaF and NK; and Group ARG
(n=20): surface treatment with a paste containing CaCO3 and 8%
arginine. After treatment, 10 samples of each group were evaluated in scanning
electron microscopy (SEM) while another 10 were included in a pH cycling
procedure for 48 hours, and then analyzed in the SEM. All SEM images were
evaluated by three calibrated examiners regarding dentin tubular obliteration.
Mann-Whitney and Kruskal-Wallis tests were used for data analysis (P< 0.05). Results: The GH, NP, and ARG groups
promoted immediate obliteration higher than the control group (P< 0.05) with
NP and ARG groups superior to GH group (P< 0.05). After pH cycling, an
increase in tubular obliteration in the GH group was observed, which was similar
to the NP and ARG groups (P> 0.05), even though all groups promoted higher
obliteration than the control group (P< 0.05). All treatments were effective
in a tubular obliteration. (Am J Dent 2015;28:342-346).
Clinical significance: The present study, using an in
vitro/pH cycling method, simulating oral conditions, showed that different
approaches could promote significant tubule obliteration, especially after pH
cycling.
Mail: Dr. Suzana
Peres Pimentel, 212 Bacelar Ave., Vila Clementino, São Paulo, SP, 14560-023, Brazil.
E-mail: suppimentel@yahoo.com
Effect of sonic vibration of an ultrasonic
toothbrush on the removal
Lina Naomi Hashizume, dds, phd & Alessandra Dariva, dds
Abstract: Purpose: To evaluate in vitro the effect
of sonic vibration of an ultrasonic toothbrush in the removal of Streptococcus mutans (S. mutans) biofilm from human enamel. Methods: S. mutans dental biofilm was formed in
vitro on human enamel blocks coated by salivary pellicle. The blocks were
incubated with a suspension of S. mutans at 37ºC for 24 or 72 hours. The blocks were divided to one of three conditions
according to the different toothbrush action modes: ultrasound plus sonic
vibration (U+SV), ultrasound-only (U) and no ultrasound and no sonic vibration
(control). Samples were exposed to each mode for 3 minutes with the toothbrush
bristles placed 5 mm away from the enamel block surface. The samples were
observed by scanning electron microscopy (SEM) and quantification of S. mutans was performed. Results: U+SV
showed lower bacterial counts compared to U and control on the 72 hour-biofilm
(P< 0.05). The SEM analysis revealed that U+SV and U disrupted the S. mutans chains in the 24- and 72-hour biofilm.
(Am J Dent 2015;28:347-350).
Clinical significance: Sonic vibration improved the
effect of an ultrasonic toothbrush in reducing bacterial viability and in
disrupting S. mutans biofilm in this in
vitro model. The ultrasonic toothbrush plus sonic vibration may be an
innovative alternative for the removal of dental biofilm.
Mail: Dr. Lina Naomi Hashizume, Department
of Preventive and Social Dentistry, Faculty of Dentistry, Federal University of
Rio Grande do Sul, Rua Ramiro Barcelos, 2492, Santana,
Porto Alegre, RS, CEP 90035-003, Brazil. E-mail: lhashizume@yahoo.com
Randomized controlled trial comparing a powered toothbrush
with distinct
John Gallob, dmd, Luis R.
Mateo, ma, Patricia Chaknis, bs, Boyce M. Morrison, Jr, phd
& Fotinos Panagakos, dmd, phd
Abstract: Purpose: To compare the plaque and gingivitis efficacy of a power
toothbrush with distinct multi-directional cleaning action (Colgate®
ProClinical® A1500 Power Toothbrush) against a manual flat-trim toothbrush
(Oral-B Indicator). Methods: This
randomized control trial was a single-center, examiner-blind, parallel-group,
design and assessed plaque removal after a single brushing, as well as plaque
removal and gingivitis reduction after 4 weeks and 12 weeks of brushing.
Qualifying subjects used their assigned toothbrush to brush their teeth under
supervision after which they were evaluated for plaque (post-brushing). Over
the next 12 weeks, subjects brushed unsupervised at home with their assigned
toothbrush. After 4 weeks and 12 weeks, subjects returned to the center for
plaque and gingivitis examinations. Results: 80 subjects were screened for eligibility and randomized into the study. 79
subjects completed the study. Both toothbrushes provided statistically
significant reductions in all plaque index scores at all time points in
comparison to the pre-brushing scores. After 4 weeks and 12 weeks,
statistically significant reductions in gingivitis and gingivitis severity
scores were observed for subjects using the power toothbrush, whereas
statistically significant increases in gingivitis and gingivitis severity were
observed for subjects using the manual toothbrush. In conclusion, relative to
the manual toothbrush, the power toothbrush provided statistically
significantly (P< 0.05) greater removal of plaque: whole-mouth (131%),
gumline (97.4%), and interproximal (220%), as well as reductions in gingivitis
(400%), and gingivitis severity (320%) after 12 weeks of use. Compared to the
manual flat-trim toothbrush, the power toothbrush with distinct
multi-directional cleaning action demonstrates statistically and clinically
significantly greater levels of plaque removal and gingivitis reduction at all
time points. (Am J Dent 2015;28:351-356).
Clinical significance: Results of this clinical trial
demonstrate that Colgate ProClinical A1500 Power Toothbrush with distinct
multi-directional cleaning action was superior to the Oral-B Indicator manual
flat-trim toothbrush in plaque removal and gingivitis reduction. These results
are important considerations for the dental professional when recommending
toothbrush options for their patients.
Mail: Dr. Fotinos Panagakos, Colgate-Palmolive Technology Center, 909 River
Road, Piscataway, NJ, 08854, USA. E-mail: foti_panagakos@colpal.com
Depth of cure of bulk fill composites with monowave
Timothy S. Menees, bs Chee Paul Lin,
phd, Dave D. Kojic,
dds, msc, John O. Burgess, dds, ms
Abstract: Purpose: To measure and compare the depth of cure (DOC) of two
bulk fill resin composites using a monowave and polywave light curing unit
(LCU) according to ISO 4049 and using custom tooth molds. Methods: The DOC of Tetric Evoceram Bulk Fill and Filtek Bulk Fill
Posterior were measured using a monowave LED LCU (Elipar S10) and a polywave
LED LCU (Bluephase G2). Metal molds were used to fabricate 10 mm long DOC
specimens (n= 10) according to ISO 4049. Uncured composite material was scraped
away with a plastic instrument and half the length of remaining composite was
measured as the DOC. Custom tooth molds were fabricated by preparing >10 mm
long square-shaped (4 x 4 mm) holes into the mesial/distal surfaces of
extracted human molars. Resin composite was placed into one end of the prepared
tooth and light polymerized. Uncured resin composite was removed from the
opposite side from which the tooth was irradiated and the tooth was sectioned
mesio-distally. Half the length of remaining cured composite was measured as
the DOC. Data were analyzed by three-way
ANOVA (α= 0.05) for factors material, LCU, and mold. Results: The main effect LCU was not significant (P= 0.58). The
interaction effect between material × mold was significant (P= 0.0001). The DOC
of the composites differed significantly only with the stainless steel mold in
which Tetric Evoceram Bulk Fill showed a deeper DOC than Filtek Bulk Fill
Posterior (4.03 ± 0.14 vs 3.56 ± 0.38 mm, P< 0.0001). (Am J Dent 2015;28:357-361).
Clinical significance: The use of a polywave light curing
unit (LCU) is not mandatory to achieve optimal DOC of a new bulk fill composite
with a germanium-based photoinitiator. However, other properties, such as
degree of conversion, strength, or hardness may be affected by choice of LCU.
Mail: Dr. Nathaniel C. Lawson, School of Dentistry,
University of Alabama at Birmingham, SDB Box 49, 1720 2nd Ave S., Birmingham,
AL 35294-0007, USA. E-mail: nlawson@uab.edu
Two pre-treatments for bonding to non-carious
cervical root dentin
Simon Flury, dds, Anne
Peutzfeldt, dr odont, phd & Adrian
Lussi, dds, dipl chem ing
Abstract: Purpose: To investigate the effect of
airborne-particle abrasion or diamond bur preparation as pre-treatment steps of
non-carious cervical root dentin regarding substance loss and bond strength. Methods: 45 dentin specimens produced
from crowns of extracted human incisors by grinding the labial surfaces with
silicon carbide papers (control) were treated with one of three adhesive
systems (Group 1A-C; A: OptiBond FL, B: Clearfil SE Bond, or C: Scotchbond
Universal; n= 15/adhesive system). Another 135 dentin specimens (n= 15/group)
produced from the labial, non-carious cervical root part of extracted human incisors
were treated with one of the adhesive systems after either no pre-treatment
(Group 2A-C), pre-treatment with airborne-particle abrasion (CoJet Prep and 50
µm aluminum oxide powder; Group 3A-C), or pre-treatment with diamond bur
preparation (40 µm grit size; Group 4A-C). Substance loss caused by the
pre-treatment was measured in Groups 3 and 4. After treatment with the adhesive
systems, resin composite was applied and all specimens were stored (37°C, 100%
humidity, 24 hours) until measurement of micro-shear bond strength (µSBS). Data
were analyzed with a nonparametric ANOVA followed by Kruskal-Wallis and
Wilcoxon rank sum tests (level of significance: α= 0.05). Results: Overall substance loss was
significantly lower in Group 3 (median: 19 µm) than in Group 4 (median: 113 µm;
P< 0.0001). There were no significant differences in µSBS between the
adhesive systems (A-C) in Group 1, Group 3, and Group 4 (P≥ 0.133). In
Group 2, OptiBond FL (Group 2A) and Clearfil SE Bond (Group 2B) yielded
significantly higher µSBS than Scotchbond Universal (Group 2C; P≤ 0.032).
For OptiBond FL and Clearfil SE Bond, there were no significant differences in
µSBS between the ground crown dentin and the non-carious cervical root dentin
regardless of any pre-treatment of the latter (both P= 0.661). For Scotchbond
Universal, the µSBS to non-carious cervical root dentin without pre-treatment
was significantly lower than to ground crown dentin and to non-carious cervical
root dentin pre-treated with airborne-particle abrasion or diamond bur
preparation (P≤ 0.014). (Am J Dent 2015;28:362-366).
Clinical significance: In order to avoid any risk of
reduced bond strength, non-carious cervical root dentin should be pre-treated
with airborne-particle abrasion or diamond bur preparation, with
airborne-particle abrasion being significantly less invasive than diamond bur
preparation.
Mail: Dr. Simon Flury, Department
of Preventive, Restorative and Pediatric Dentistry, School of Dental Medicine,
University of Bern, Freiburgstrasse 7, CH-3010 Bern, Switzerland. E-mail: simon.flury@zmk.unibe.ch
Influence of organic acids present in oral biofilm
on the durability
Stéphane
da Silva, dds, ms, Eduardo Moreira da Silva, dds,
msc, phd, Marcella Bruna Ferreira Delphim,
Abstract: Purpose: To evaluate the
repair bond strength after storage in water, lactic and propionic acid after 7
days and 6 months and the sorption and solubility of resin composites used. Methods: Five cylinders of each resin composite (microhybrid, nanofilled and silorane-based
composite) were prepared. Specimens were aged with thermocycling (5 and 55°C)
5,000 times. A repair procedure was performed using intraoral sandblasting with
50-µm aluminum oxide, application of an adhesive system and cylinder of
composite was fabricated. Specimens were sectioned into beams and stored in
three immersion media: water, propionic acid and lactic acid. The microtensile
bond strength was measured after periods of 7 days and 6 months. Sorption and
solubility were evaluated using 15 specimens (Ø= 6 mm; h= 1 mm) of each resin
composite, which were prepared and assigned into three groups (n= 5) according
to the immersion media (water, propionic acid and lactic acid). Data were
analyzed using one-way/two-way/three-way ANOVA and Tukey’s test (α= 0.05). Results: The resin composites, immersion media and time of immersion did
not affect the repair bond strength (microhybrid 38.3 to 40.9 MPa; nanofilled
38.7 to 42.2 MPa; silorane 41.2 to 51.1 MPa). Additionally, the immersion media
did not affect the sorption and solubility. The silorane-based composite
presented the lowest sorption (10.5 to 12.1µg/mm3) and solubility
(-2.4 to -2.7 µg/mm3), while the nanofilled methacrylate-based
composite showed the highest sorption (32.1 to 33.6 µg/mm3).
Regarding solubility, the nanofilled and microhybrid methacrylate-based
composites did not present statistically significant differences. (Am J Dent 2015;28:367-372).
Clinical
significance: The acids of oral biofilm have no influence on the
sorption and solubility of resin composites (microhybrid, nanofilled and
silorane-based) or in composite repair bond strength. Therefore, if an effective surface treatment
is done, repair is a procedure that
could be indicated for areas susceptible to plaque accumulation.
Mail: Dr. Cristiane Mariote
Amaral, School of Dentistry, Federal Fluminense University, Rua Mário Santos
Braga, nº 30, Campus Valonguinho, Centro, Niterói, RJ, CEP 24020-140,
Brazil. E-mail: camaral@vm.uff.br