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August 2011
Laboratory
efficacy of three compact toothbrushes to reduce
Samuel L. Yankell, ms, phd,
rdh, Caren M. Barnes, rdh,
ms, Xiuren Shi, dds
& James Cwik, bsba,
mba
Abstract: Purpose: To evaluate the effect of three toothbrushes [GUM Summit+Compact Head, GUM Technique Deep Clean Compact Head,
and Oral-B Indicator 35 (compact head)] on plaque reduction in difficult to
reach areas: interproximal sites (Interproximal
Access Efficacy, IAE), the gingival margin (Gingival Margin Cleaning, GMC) and
under the gumline (Subgingival
Access Efficacy, SAE). Methods: Six
toothbrushes from each product group were randomly tested four times for a
total of 24 tests on each toothbrush design. In the IAE studies, toothbrushing was conducted for 15 seconds using horizontal
and vertical brushing motions, simulated anterior and posterior teeth and a
brushing pressure of 250 g. IAE was recorded as the maximum width of artificial
plaque removed. In the GMC and SAE assays, the toothbrush to be tested was
aligned with the papillae of artificial gingiva placed over simulated posterior
teeth and brushing was conducted for 15 seconds using horizontal brushing and a
brushing pressure of 500 g. The GMC efficacy was recorded as the maximum length
of artificial plaque removed at the gingival margin. The maximum depth of the
plaque substrate removed under the gingiva was recorded as the SAE. Significant
mean differences between the toothbrushes were determined using ANOVA and Tukey’s test for pairwise
comparisons with a significance level of P< 0.05. Results: In all three assays conducted, the GUM
Clinical significance: The presence of dental plaque at
interproximal, subgingival
and gingival margin sites will result in the development of gingivitis if not
removed regularly and thoroughly. The demonstrated efficacy of the GUM
Address: Dr. S. L. Yankell, Yankell Research
Consultants, Inc., 405 East Second Street, Moorestown,
NJ, 08057 USA. E-mail: YRCInc@aol.com
Color stability
of chemically activated reline resin after microwave disinfection: A 1-year
clinical trial
Roberta Chuqui
Ribeiro, dds, msc, phd, Eunice Teresinha
Giampaolo, dds, msc, phd,
Abstract: Purpose: To evaluate the effect of
microwave disinfection on the color stability of a hard chairside
reline resin after a 1-year service period. Methods: 40 adult patients aged between
30-75 years, who required denture reline treatment, participated in this study.
Tokuyama Rebase II was used to reline complete maxillary dentures. The
edentulous subjects were randomly divided into two groups (n=20) and dentures
were cleansed according to two methods: CG (control group) - brushing with
coconut soap and soft toothbrush; DG (disinfection group) - brushing according
to previous methods and microwave disinfection once a week for 3 minutes at
650W. Color parameters in L*a*b* were recorded by spectrophotometer immediately
after the reline, at 7 and 15 days, 1, 3, 6 and 9 months and 1 year
post-placement. Data were analyzed by two-way repeated-measures ANOVA and Tukey tests (α= 0.05). Results: Color alteration values of DG were significantly lower
than those of CG (P< 0.05). Color changes observed after 15 days were
greater than values obtained at 7 days recall (P< 0.05). All color changes
observed for the CG were considered noticeable (between 1.5 and 3.0 NBS). In
DG, color change was slight (between 0.5 and 1.5 NBS). There were statistically
significant differences between L* values obtained initially and after 3
months, between 15 days and 3 months and between 15 days and 1 year (P< 0.05).
No significant differences were observed between group and time for the
parameters a* and b*. (Am J Dent 2011;24:200-204).
Clinical significance: Microwave disinfection caused
improvement in color stability of the reline material.
Address: Dr.
Roberta Chuqui Ribeiro, Araraquara Dental School – UNESP, R. Humaitá, nº1680,
CEP 14801-903 Araraquara, São Paulo, Brazil. E-
mail: robertachuqui@yahoo.com.br
Enamel
protection: A comparison of marketed dentifrice performance against dental
erosion
Abstract: Purpose: To
determine the relative ability of various marketed toothpastes formulated with
either stabilized stannous fluoride (SnF2), sodium fluoride (NaF), or sodium monofluorophosphate
(SMFP) to protect human enamel against the initiation and progression of damage
due to dietary acid attack, using a laboratory erosion cycling model. Methods: Cores of ground and polished
enamel from extracted human teeth were soaked in pooled, human saliva (pellicle
formation) and then subjected to erosion cycling conditions that included
exposure of tooth specimens to: (1) treatments in a 1:3 slurry (w/w) of
toothpastes and saliva; and (2) acid challenges using either citric acid (Study
1) or both citric and phosphoric acids (Study 2). These acids represent
potentially damaging acids found in common food and drinks. Upon completion of
treatments, specimens were analyzed with regard to the depth of tooth mineral
removed from exposed areas of the treated specimens over the course of the
study. Two studies were conducted: Study 1 included a
marketed, stabilized SnF2 toothpaste vs. marketed NaF toothpastes; Study 2
tested the same stabilized SnF2 product compared to a marketed SMFP
toothpaste and a NaF control. Results: The stabilized SnF2 toothpaste included in
these studies demonstrated a highly significant reduction in enamel surface
loss, relative to the control, in each study: Study 1 = 65% reduction; Study 2
= 58% reduction when using citric acid and 84% reduction when using phosphoric
acid. Products formulated with NaF resulted in a net
loss of between +1% and -21%, with none of the NaF toothpastes
performing significantly different from the control (P< 0.05, ANOVA). For
the SMFP product included in Study 2, results were also not significantly
different from the NaF control. In both studies, the
stabilized SnF2 paste demonstrated a highly significant level of
protection compared to all other test groups included in the study, regardless
of the type of dietary acid challenge considered. (Am J Dent 2011;24:205-210).
Clinical significance: Results of these studies
suggested that the stabilized SnF2 paste could be used to provide
significant acid protection over that provided by conventional fluoride
products.
Address: Sandra L. Eversole The
Procter and Gamble Company, Advanced Technology and Innovation Department,
Enamel Care Research Group, 8700 Mason-Montgomery Road, Mason, OH 45040, USA.
E- mail: eversole.sl@pg.com.
Incomplete caries removal in deep lesions: A 10-year
prospective study
Abstract: Purpose: To
follow-up teeth with deep caries lesions submitted to incomplete caries removal
over a 10-year period. Methods: 27
subjects (32 permanent posterior teeth) with deep caries lesions composed the
sample. In this single-arm long-term prospective study, the inclusion criteria
were risk of pulp exposure during caries excavation, positive response to the
cold test, absence of spontaneous pain or sensitivity during percussion, and
radiographic absence of a periapical lesion. Subjects were submitted to the
following procedures: complete caries removal from the surrounding cavity
walls, incomplete caries removal from the pulpal
wall, capping with a calcium hydroxide cement, and
sealing with a modified zinc oxide-eugenol cement.
After 6-7 months, the temporary sealing was removed for methodological purposes
(no further excavation was performed), and teeth were capped with a calcium
hydroxide cement and filled with resin composite. Clinical and radiographic
assessments were conducted after 6-7 months, 1.5, 3, 5 and 10 years. Success
was defined as clinical and radiographic signs and symptoms of pulp sensitivity
while failure was defined as endodontic treatment need. Results: Over 10 years, one tooth was excluded from the sample
(pulp exposure during treatment), five were lost to recall, 10 had therapy
failure (five fractures and four necroses leading to endodontic treatment need,
and one extraction) and 16 had therapy success (pulp sensitivity). Overall
survival rates were 97%, 90%, 82% and 63% at 1.5-, 3-, 5- and 10-year
follow-ups, respectively. Teeth with two or more restored surfaces failed significantly
more than teeth with one restored surface (P= 0.01). (Am J Dent 2011;24:211-214).
Clinical significance: Incomplete caries removal may
be seen as an alternative to complete excavation in deep caries lesions,
arresting caries progression, preventing pulp exposure; therefore the need for
more invasive techniques, such as direct pulp capping or endodontics
may be avoided.
Address: Dr. Marisa Maltz,
Department of Social and Preventive Dentistry, Faculty of Dentistry, UFRGS,
Ramiro Barcelos, 2492, Bom Fim 90035-003, Brazil. E- mail: marisa.maltz@gmail.com
Microtensile bond strengths and interfacial examination
Abstract:
Purpose: To
study the effect of acid etching and the application of a hydrophobic bonding
resin on the microtensile bond strengths (µTBS) and marginal sealing of the
1-step self-etch adhesive Adper Easy Bond (AEB). Methods: Middle dentin was exposed in
30 extracted molars and randomly divided into six groups: (1) AEB applied as
per manufacturer's directions; (2) as in AEB, but one coat of hydrophobic resin
(HR) was applied and cured over AEB (AEB+HR); (3) etching with 35% H3PO4
for 15 seconds followed by AEB (Etch+AEB); (4) as in
group Etch+AEB, but one coat of HR was applied and
cured over AEB (Etch+AEB+HR); (5) Adper
Single Bond Plus, the 2-step etch-&-rinse adhesive control (ASB); (6) Adper Scotchbond Multi-Purpose,
the 3-step etch-&-rinse adhesive control (SBMP). Buildups were constructed
with Filtek Z250 and cured in three increments of 2
mm each. Specimens were sectioned with a slow-speed diamond saw under water in
X and Y directions to obtain bonded sticks with a cross section of 0.8 ± 0.2 mm2
and tested to failure in tension mode at a crosshead speed of 1 mm/minute.
Statistical analyses were computed using one-way ANOVA followed by Duncan’s
post-hoc test at P< 0.05. For marginal sealing, 36 Class V preparations were
restored with one of the six adhesive combinations and processed with 50% ammoniacal silver nitrate. After sectioning, specimens were
observed under a backscattered FE-SEM to evaluate silver infiltration into the
resin-dentin interface, which was measured in ranks (0-4) and compared with
non-parametric statistical tests (P< 0.05). Results: AEB resulted in statistically lower mean µTBS than all
other groups at P< 0.05. All the remaining groups resulted in statistically
similar mean µTBS. For marginal sealing, data were grouped in three statistical
subsets: Groups AEB and AEB+HR resulted in statistically less silver
infiltration than groups Etch+AEB and Etch+AEB+HR. Groups ASB and SBMP resulted in similar silver
infiltration compared to Groups AEB and AEB+HR. The nanoleakage
pattern consisted of agglomerates of silver deposits located predominantly in
the hybrid layer, while reticular or water-tree silver deposits were observed
in both the AEB and ASB adhesive layers. (Am
J Dent 2011;24:215-220).
Clinical significance: As with other 1-step self-etch
adhesives, Adper Easy Bond is more reliable in the
laboratory when used as a 2-step self-etch adhesive.
Address: Dr. Jorge Perdigão,
University of Minnesota, Department of Restorative Sciences, 515 SE Delaware
St, 8-450 Moos Tower, Minneapolis, MN 55455, USA. E- mail: perdi001@umn.edu
Clinical versus
laboratory adhesive performance to wet and dry demineralized
primary dentin
Ana ClaÚdia Chibinski, dds, ms, Rodrigo Stanislawczuk, dds, ms, Douglas
Augusto Roderjan, dds,
ms,
Abstract: Purpose: To evaluate the influence of dentin moisture on bond
strengths of an etch-and-rinse bonding agent to primary dentin clinically and
in the laboratory. Methods: The
sample consisted of two groups of 20 caries-free primary second molars: molars
in exfoliation period (clinical group) and extracted molars (laboratory group).
Class I cavities were prepared in all specimens leaving a flat dentin surface
on the pulpal floor. A two-step etch-and-rinse
adhesive was vigorously rubbed on either dry (n= 5) or wet demineralized
dentin (n= 5) under clinical or laboratory conditions. After restorative
procedures, the teeth from the clinical group were extracted after 20 minutes.
All samples were processed and underwent microtensile
bond strength test and silver nitrate uptake evaluation under scanning electron
microscopy. Results: Statistically
higher bond strength values were observed when the bonding was performed under
laboratory conditions and on a wet demineralized
dentin. Most of the failures were adhesive and mixed irrespective of the
experimental condition. Silver nitrate uptake occurred in all groups
irrespective of the experimental condition. Resin-dentin bond strengths
produced in the laboratory in primary teeth may overestimate those produced
under clinical circumstances. (Am J Dent
2011;24:221-225).
Clinical significance: Wet bonding technique still
seems to be required for primary teeth in order to achieve high immediate
resin-dentin bond strength values for the etch-and-rinse adhesive system
tested.
Address: Dr.
Alessandra Reis, Rua General Osório, Apto 422, Centro, Ponta Grossa, Paraná,
Brazil – 84010-080. E-
mail:
reis_ale@hotmail.com
The effect of polymerization procedure
on Vickers hardness
Simon Flury, dds, Anne Peutzfeldt, dds,
phd, dr odont
& Adrian Lussi, dds,
dipl chem ing
Abstract:
Purpose: To
investigate the surface hardness (Vickers hardness, HVN) of one light-curing flowable resin composite and five dual-curing resin cements
after different polymerization procedures. Methods:
The HVN was measured with a hardness-indentation device on one light-curing flowable resin composite (Tetric EvoFlow) and five dual-curing resin cements (Panavia F2.0, SpeedCEM, RelyX Unicem Clicker, SmartCem2
and iCEM) after the resin material had been cured at
constant 30°C according to one of five polymerization procedures (n=
30/procedure and material): (1) 5-minute light-curing (positive control;
prolonged light-curing), (2) 40-second light-curing (immediate light-curing),
(3) 6-minute auto-curing (negative control; dual-curing resin cements only),
(4) 6-minute auto-curing followed by 40-second light-curing (delayed
light-curing), and (5) 5-second light-curing, 1-minute auto-curing and 40-second light-curing (instructions for removal of
excess cement). A Kruskal Wallis test followed by pairwise Wilcoxon rank-sum tests
with Bonferroni-Holm adjustment was applied for each
material and procedure (level of significance: α= 0.05). Results: For each material, Procedure 1
showed the significantly highest HVN and Procedure 3 the significantly lowest
HVN. Procedure 4 showed significantly increased HVN for each material compared
to Procedure 3. With Procedure 1, Panavia F2.0 and RelyX Unicem yielded
significantly higher HVN than the other resin materials. With Procedure 3, no
significant differences in HVN were found between Panavia
F2.0, SpeedCEM and SmartCem2 which all showed
significantly higher HVN than RelyX Unicem and iCEM. (Am J Dent 2011;24:226-232).
Clinical
significance:
Prolonged light-curing increased the surface hardness. Auto-curing alone
resulted in the lowest surface hardness. However, light-curing after
auto-curing was able to restore the surface hardness. The light-curing flowable resin composite did not perform better than the
dual-curing resin cements. Certain dual-curing resin cements performed poorly
when only auto-cured and should be used only when effective light-curing can be
guaranteed.
Address:
Dr. Simon Flury, Freiburgstrasse 7, CH-3010 Bern,
Switzerland. E- mail:
simon.flury@zmk.unibe.ch
Influence of the activation mode of a
self-etch resin-based luting cement
Adriano Melo de MendonÇa, dds, ms, phd, Camila
Favero de Oliveira, dds, ms, phd, Josimeri Hebling, dds, ms, phd
Abstract: Purpose: To evaluate
the cytotoxicity of a self-etch resin-based luting cement, RelyXUnicem (RXU)
upon chemical or dual cure and with or without interposition of IPS d.SIGN (IPSD) or IPS Empress II (IPSE) ceramic discs between
cement and light source. Methods:
112 RXU specimens were subjected to different curing conditions and incubated
in culture medium (DMEM) to obtain extracts. The following groups were formed:
G1: DMEM (control); G2: dual RXU; G3: chemical RXU; G4: dual RXU+IPSD; G5:
chemical RXU+IPSD; G6: dual RXU+IPSE; and G7: chemical RXU+IPSE. Cultured odontoblast-like cells were incubated for 24 hours in
contact with the extracts. Data from cell metabolism (CM), total protein dosage
(TPD) and alkaline phosphatase activity (APA) were
obtained and analyzed statistically (α= 0.05; Kruskal
Wallis and Mann-Whitney tests). Cell morphology was analyzed by SEM. Results: CM and APA were significantly
lower in G3 and G7 than in G1 (P< 0.05). Significant TPD decrease occurred
in G5 and G7 compared to G1 (P< 0.05). Only G4 and G6 presented CM changes.
RXU caused no cytotoxicity when subjected to dual
cure without ceramic interposition. However, mild cytopathic
effects were observed after chemical setting without ceramic interposition, and
after chemical and dual activation under ceramic discs. (Am J Dent 2011;24:233-238).
Clinical significance: The interposition of ceramic
restoration between the light source and self-etching luting
cements during their chemical and/or dual polymerization may decrease the
degree of monomer-polymer conversion. Consequently, the release of unreacted monomers from these resin-based cements may cause
toxic effects to pulp cells.
Address: Prof. Dr. Carlos Alberto de Souza Costa,
Department of Physiology and Pathology, Faculty of Dentistry of Araraquara, Paulista State
University (UNESP), Rua Humaitá,
1680, Centro, P.O. Box 331, CEP: 14801-903 Araraquara,
SP, Brazil. E- mail: casouzac@foar.unesp.br
The effect of
6-month water storage on the bond strength of self-etch adhesives bonded to
dentin
Abstract: Purpose: To evaluate the microtensile
bond strengths (µTBS) of 1-step vs.
2-step self-etch systems to dentin after 24 hours and after 6 months of water
storage. Methods: Resin composite
buildups were bonded to occlusal dentin of third
molars using the following adhesives: Xeno IV (XE, Dentsply), G-Bond (GB, GC Inc), Clearfil
S3 Bond (CS3, Kuraray); Adper Prompt L-Pop (AD, 3M
ESPE); Go (GO, SDI), All Bond SE (ABSE 1-step or ABSE 2-step, Bisco) and Clearfil SE Bond (CSE,
Kuraray). The bonded sticks (cross-sectioned area of 0.8-0.9 mm2)
originated from the same teeth were randomly divided to be tested after 24
hours or after 6 months of water storage. The data was submitted to two-way
repeated measures ANOVA and Tukey’s test with and
without the inclusion of premature failures (PF) (α = 0.05). Results: The inclusion of PF resulted
in different statistically significant means for CS3, CSE and AD (P< 0.05).
Only the ABSE2 showed stable bonds after 6 months of water storage (P>
0.05). (Am J Dent 2011;24:239-244).
Clinical significance: All Bond SE systems showed
stable bonds after 6-month water storage when used in the 2-step approach.
Address: Dr.
Alessandra Reis, University Estadual de Ponta Grossa, Mestrado em Odontologia,
Av. Carlos Cavalcanti, 4748, Bloco M, Sala 64A, – Ponta Grossa, Paraná 84010-900,
Brazil. E- mail: reis_ale@hotmail.com
Surface roughness evaluation and shade changes of a nanofilled resin composite after bleaching and immersion in
staining solutions
Abstract: Purpose: To
investigate the effect of bleaching and staining solutions on roughness and
shade changes in a nanofilled resin composite [Filtek Supreme (FS)]. Methods:
FS specimens (n= 135) were light cured and separated into groups (n=45)
that were bleached with 10% carbamide peroxide (CP)
agent or 16% or 35% hydrogen peroxide (HP). In the first two groups the
bleaching gel was used for 4 hours a day, during 14 days, and for the third
group in three sessions of 45 minutes. Each group was subdivided (n=15) and
immersed in coffee, red wine or distilled water for 3 hours a day during 40
days. The roughness values (Ra) and shade (parameter CIELab)
were evaluated at baseline, after bleaching and after staining. The data was
analyzed by ANOVA and Tukey test or Kruskal Wallis. Results:
The effects on specimens varied depending on the bleaching product and
staining solution. FS after bleaching and after staining presented higher
roughness. In the evaluation of shade changes after bleaching, it was observed
that resin color changed and that 35% hydrogen peroxide bleached the resin more
than the others. After staining in three solutions, all specimens changed color
and wine showed the higher staining capacity. (Am J Dent 2011;24:245-249).
Clinical
significance: Filtek Supreme nanofilled resin composite
can undergo changes in the roughness and color after whitening or staining.
Address:
Prof. Dr. Roberta Tarkany Basting, Faculty of
Dentistry and São Leopoldo Mandic
Dental Research Center, Department of Restorative-Operative Dentistry,
University of Campinas, Rua José Rocha Junqueira 13, Bairro Swift, Campinas,
SP CEP: 13045-755, Brazil. E- mail:
rbasting@yahoo.com
Temperature rise during
photo-polymerization for onlay luting
Abstract:
Purposes: (1) To
measure the temperature rise during long-time irradiation needed to lute
adhesive indirect restorations, with one halogen and five LED high-power lamps,
in a simulated oral environment, and (2) to propose a technique to reduce heat.
Methods: Temperature within the pulp
chamber of an extracted human molar in a 35°C water bath, before and after
restoration with a ceramic onlay, was continuously
recorded during 3 x 120 seconds of irradiation for different curing regimens,
with and without cooling by compressed air, water and water spray. Temperature
rise in a thermo-insulated well was also measured during 120 seconds of
irradiation with LEDemetron II and TuTu. Results:
Maximal temperature rise of 6.2°C/7.7°C on intact/onlay
restored tooth was found after 3 x 120 seconds of irradiation. Compressed air
application reduced the temperature by 4°C for LEDemetron
II, while water spray increased the temperature by 15.1°C for TuTu. Temperature decreased with irradiation distance,
except for LEDemetron II. Air was heated up to 65°C after
120 seconds of irradiation in an insulated well with TuTu.
(Am J Dent 2011;24:250-256).
Clinical
significance:
Recent high-power LED curing units developed high temperatures during extended
irradiation. Active cooling may be effective to reduce heat during prolonged
polymerization times used for luting of indirect
adhesive restorations with light-cured materials.
Address:
Dr. Ioana Onisor, School of Dentistry, University of
Geneva, Rue Barthélemy-Menn 19, CH-1205 Geneva,
Switzerland. E- mail: iona.onisor@unige.ch
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