Advertisements
August 2022 Abstracts
Fracture
strength of different veneers on polyetheretherketone (PEEK)
Samet Tekin, dds, phd, Fatih Demirci, dds, phd & Metin Bakir, dds, phd
Abstract: Purpose: To evaluate the fracture strength of polyetheretherketone (PEEK) single crowns veneered with different materials produced by
computer-aided design (CAD)-computer-aided manufacture (CAM) after aging. Methods: 60 stainless-steel master dies were prepared with a 1 mm-wide deep chamfer.
Sixty PEEK frameworks were produced with a CAD-CAM system for the right
maxillary first molar tooth on the dies. PEEK frameworks were divided into six
groups (n= 10) according to veneering materials (five CAD-CAM materials and a
resin composite). Group ZR: monolithic zirconia (Upcera ST-Color); Group EC: lithium disilicate glass-ceramic (IPS e.max CAD); Group LU: resin nano-ceramic (Lava Ultimate); Group VM: feldspathic
ceramic (Vitablocs Mark II); Group VS:
zirconia-reinforced lithium silicate glass-ceramic (VITA Suprinity);
and Group CR: indirect resin composite (Gradia). All
samples were subjected to a fracture strength test in a universal test device
after thermo-mechanical aging and then the results were analyzed statistically
using one-way ANOVA and Tukey’s post hoc test. In addition, post-fracture analyses
of all samples were performed with a stereomicroscope. Results: The
differences in fracture strength values of different veneer materials in single
crowns with a PEEK framework were statistically significant (P< 0.05).
Fracture strength was highest in Group ZR (1665 N), followed by Groups LU (1440
N), EC (1249 N), CR (918 N), VS (754 N), and VM (655 N). (Am J Dent 2022;35:167-171).
Clinical
significance: PEEK frameworks may have the potential to be used with many veneer materials of
different content and properties in fixed partial prostheses.
Mail: Dr.
Samet Tekin, Department of Prosthodontics, Faculty of
Dentistry, Firat University, Elazig 23119, Turkey. E-mail: s.tekin@firat.edu.tr
Effects of radiant exposure and distance on
resin-based
Alyssa Teixeira Obeid, dds, ms, Dave Darko Kojic, dmd, ms, phd, Chris Felix, bsc,
Abstract: Purpose: To evaluate the hardness profile
of three resin-based restorative composites (RBC) (Filtek Z250XT, Filtek One Bulk Fill, Filtek Bulk Fill Flow) polymerized by a multi-wave curing light. Methods: Specimens (n= 12) were prepared by inserting 2 mm RBC increments into a
split-mold and polymerized from the top using either 20- or 40-second exposure
times. Specimen curing was performed directly at a 1 mm distance
(control-group) or through an ivorine-tooth slot preparation at a 5 mm distance
(experimental-group). Specimens were stored (37 ± 1°C/24 hours), then subjected
to Knoop indenter (25g/5 seconds). Specimens’ KHN values were obtained from the
upper and lower surfaces. Relative hardness (RH) (lower-to-upper ratio) was
calculated for each specimen. Data were analyzed with three-way ANOVA and Tukey’s
HSD (α= 0.05). Results: There was no significant RH difference
among RBCs in the control group, regardless of the exposure time (P> 0.05).
Average RH ratios for all RBCs tested in this group were greater than 0.80.
However, the average RH values of the experimental RBC group were significantly
lower. The RH for Z250 was 0.39 in the 20-second group, while RH was 0.63 in
the 40-second group. BF had an RH ratio of 0.70 in the 20-second and 0.72 in
the 40-second group, while One Bulk had a ratio of 0.65 in the 20-second and
0.71 in the 40-second groups. Doubled exposure time substantially increased RH
of all tested materials at a 1 mm tip-to-material distance. Clinically relevant
5 mm light-tip to material-surface distance significantly reduced
polymerization efficacy of RBC specimens, regardless of the exposure time. (Am
J Dent 2022;35:172-177).
Clinical
significance: Adequate
light-polymerization of resin-based direct restoratives is necessary for
long-term clinical success. Polymerizing Class 2 restorations is challenging
due to a hard-to-reach location and an increased distance between the light
source and the restorative material. Insufficient polymerization is often seen
at the bottom of the proximal box of the Class 2 cavity, with a detrimental
effect on restoration longevity.
Mail: Dr. Alyssa Teixeira Obeid,
Department of Operative Dentistry, Endodontics, and Dental Materials, Bauru
School of Dentistry, University of São
Paulo, Al. Dr. Octávio Pinheiro Brisolla, 9-75,
17.012-901, Bauru, São Paulo, Brazil. E-mail: alyssa.obeid@usp.br
Depth of cure of
dual- and light-cure bulk-fill resin composites
Mohamed Elshirbeny Elawsya, bds, mds, Marmar Ahmed Montaser, bds, mds, phd,
Abstract: Purpose: To evaluate the degree of conversion (DC), Vickers
microhardness (VMH), and depth of cure of dual-cure and light-cure bulk-fill
resin composites (BFRCs). Methods: One dual-cure (Fill-Up) and two
light-cure (QuiXfil and Tetric N-Ceram Bulk Fill) BFRCs were investigated. For each tested BFRC, 11
cylindrical specimens (5 mm diameter, 4 mm height) were prepared, and light
cured for 10 seconds (n= 11). DC was obtained by attenuated total reflectance-Fourier
transform infrared spectroscopy (ATR-FTIR), and VMH was obtained using a VMH
tester. The specimens were measured for DC and VMH at top and bottom surfaces.
Statistical analysis was performed using two-way ANOVA, Tukey’s post-hoc, and
Pearson correlation tests (P< 0.05). Results: Fill-Up and Tetric N-Ceram Bulk Fill revealed significantly higher DC
and VMH values on the top surfaces than that on the bottom surfaces, whereas QuiXfil revealed no significant difference between top and
bottom surfaces for DC and VMH. All tested BFRCs showed bottom/top ratios >80% for both DC and VMH. Each tested BFRC showed a
significant positive correlation between DC and VMH. All tested BFRCs had adequate
depth of cure, but only QuiXfil had a uniform depth
of cure. Both DC and VMH bottom/top ratios were effective for depth of cure
evaluation. (Am J Dent 2022;35:185-190).
Clinical
significance: QuiXfil, Tetric N-Ceram Bulk
Fill, and Fill-Up BFRCs were well cured up to a 4 mm depth. Although Fill-Up (dual-cure) can be used with its
chemical-curing mode, light curing improved DC and VMH values of the top layer.
Distinct variance in DC and VMH among the three tested BFRCs may affect their
clinical performance.
Mail: Dr. Mohamed Elshirbeny Elawsya, Department of
Operative Dentistry, Faculty of Dentistry, Mansoura University, Algomhoria Street, Mansoura, Aldakhlia,
Egypt 35516. E-mail:
mohamedelshirbeny@mans.edu.eg
Influence of diet and red wine exposure on the velocity
of at home bleaching:
Jamile Menezes de Souza, dds, João Paulo Alves da Silva Aguiar, dds, Washington
José Batista das Neves, dds, Luís Felipe Espíndola-Castro, dds, msc, phd, Daene
Patrícia Tenório Salvador da Costa, dds, msc, phd
& Claudio Heliomar Vicente da Silva, dds, msc. phd
Abstract: Purpose: To evaluate the influence of diet
and exposure to red wine on the treatment velocity, clinical results,
postoperative tooth sensitivity, and patient satisfaction after tooth
bleaching. Methods: 45 subjects undergoing home bleaching with 16%
carbamide peroxide (CP) were randomly separated into three groups, depending on
the restriction of colored food and the use of a red wine mouthwash. Shades of
teeth 11 and 21 were assessed using a digital spectrophotometer (VITA Easy
Shade) at T0 (before treatment), T7 (7 days after treatment), T15 (15 days
after treatment), and T30 (30 days after treatment). The assessments were
verified using the CIELab system (values of L*, a*,
and b*) and the change in shade was calculated (ΔE, ΔL, Δa, and Δb). Results: No statistically significant differences in ΔE, ΔL, Δa, and Δb were found
between the groups. However, at T7, the group restricted from colored foods without
red wine mouthwash had meaningful variations in L*, a*, and b*. Statistically,
there was no difference in tooth sensitivity between the groups in the 7- and
15-day periods. Patients in the restricted colored foods without red wine
mouthwash group were more satisfied after the end of treatment. (Am J Dent 2022;35:191-196).
Clinical
significance: Tooth bleaching with 16% carbamide peroxide may be performed in subjects with
colorant-rich diets without influencing the clinical outcome.
Mail: Dr. Claudio Heliomar Vicente da Silva, Department of Prosthodontics and Orofacial Surgery, Avenue
Prof. Moraes Rego, 1235, Cidade Universitária,
Recife, Pernambuco, Brazil, 50670-901. E-mail: claudio_rec@hotmail.com
Periapical disease in post-stroke patients
Ilan Rotstein, dds & Joseph Katz, dmd
Abstract: Purpose: To assess the prevalence of
acute periapical abscesses (PAs) in patients with history of stroke. Methods: Integrated data of hospital
patients was used. Data from the corresponding diagnosis codes for PAs and
stroke were retrieved by searching the appropriate query in the database. The
odds ratio (OR) of acute PAs and its association with post-stroke conditions
was calculated and analyzed statistically. Results: The prevalence of acute PAs in patients with stroke history was 1.39% as
compared to 0.6% in the general patient population of the hospital. The OR was
2.78 and the difference was statistically significant (P< 0.0001). The
prevalence of acute PAs in patients with a history of hemorrhagic stroke was
1.19% and the OR was 2.38. The difference was statistically significant (P< 0.0001).
The prevalence of acute PAs in patients with a history of cerebral infarction
was 1.55% and the OR was 3.11. The difference was statistically significant (P<
0.0001). The prevalence of acute PAs in patients with a history of cerebral
infarction without hypertension was 0.87% and the OR was 1.75. The difference was
statistically significant (P< 0.0001). (Am
J Dent 2022;35:197-199).
Clinical significance: Oral healthcare providers should
be aware of the possible higher prevalence of periapical abscesses in post-stroke
patients. This can include patients with a history of hemorrhagic stroke or
cerebral infarction.
Mail: Dr. Ilan Rotstein, 3585 S.
Vermont Avenue, Unit 7877, Los Angeles, CA 90007, USA. E-mail: ilan@usc.edu
Effect of
ultrasonic scaling and air polishing on the surface roughness
Fatih
Demirci, dds, phd, Merve Birgealp Erdem, dds, phd, Samet Tekin, dds, phd, & Cevdet Caliskan, dds, phd,
Abstract: Purpose: To evaluate the effects of
ultrasonic scaling (US) and air polishing (AP) on four polyetheretherketone (PEEK) composites. Methods: One hundred-twenty 15 × 3 mm discs of PEEK
specimens were divided into four groups (n=30): Unfilled PEEK(U-PEEK), carbon
fiber-reinforced PEEK(CFR-PEEK), glass fiber-reinforced PEEK(GFR-PEEK), and
ceramic-filled PEEK(CF-PEEK). Each group was further divided into three
subgroups (n = 10): control, US, and AP. Profilometry and scanning electron microscopy
were used to analyze and evaluate surface roughness (SR). Statistical analyses
of the data obtained were conducted using Shapiro-Wilk, Welch, and Games-Howell
tests. Results: When the SR values of the specimens with US cleaning
were evaluated, a statistically significant difference was found between the
groups (P< 0.05). When the SR values of the specimens with AP cleaning were
analyzed, there was a statistically significant difference in the CF-PEEK group
(P< 0.05), whereas the other groups were not significantly different (P>
0.05). More studies are needed on CFR-PEEK and GFR-PEEK materials offered as
alternatives to CF-PEEK in dentistry. (Am J Dent 2022;35:200-204).
Clinical
significance: Dental instruments affect the different PEEK materials, as well as causing
surface roughness in many restorative materials used in dentistry. Surface
roughness that occurs in dental restorations can cause bacterial adhesion. It
is clinically important to choose the dental instrument according to the type
of PEEK used for dental implant or prosthetic restoration in the clinic.
Mail: Dr. Samet Tekin, Firat University, Faculty
of Dentistry, Department of Prosthodontics, Elazig, Turkey. E-mail: s.tekin@firat.edu.tr
Human root
dentin microhardness and degradation
Sonia
Guzmán, dds, phd, Mario Caccia, phd, Olga Cortés, dds, phd, Jose M. Bolarin, phd
Abstract: Purpose: To investigate
and compare the effects of the two widely used regenerative endodontics medicaments:
Triple antibiotic paste (ciprofloxacine-metronidazole-clindamycin) and calcium
hydroxide on the microhardness and degradation of human root dentin. Methods: Following ethical approval and subject consent to use
teeth in this research study, 60 singled-rooted permanent human teeth were
randomly divided into six groups: (1) Tri-antibiotic paste with distilled
water, or with (2) propylene glycol, (3) calcium hydroxide with distilled
water, (4) calcium hydroxide propylene glycol, (5) untreated extracted teeth as
negative controls, or (6) teeth instrumented and filled with calcium hydroxide
or tri-antibiotic paste as positive controls. The microhardness tests were
conducted after 1 and 2 months of exposure to the medicaments using a Vickers
microhardness tester. Raman spectroscopy and energy dispersive x-ray
spectroscopy were used to evaluate the chemistry and structure of the root
dentin. Results: There were differences in
the dentin microhardness following treatment with the medicaments or controls (P<
0.05). The time of root dentin exposure to the medicaments was similar (P>
0.05). The root dentin microhardness was lower in the teeth treated with the
triple antibiotic paste or calcium hydroxide when combined with propylene
glycol. The root dentin collagen in these treated teeth were also significantly
degraded when viewed with Raman spectroscopy and energy dispersive x-ray
spectroscopy, whereas the inorganic phase (dentin) remained unaltered. Samples
exposed to the antimicrobial agents with water as a vehicle exhibited stronger
microhardness and less degradation. (Am J Dent 2022;35:205-211).
Mail:
Dr. Olga Cortés, Clínica Odontológica, 2 pl, Hospital Morales Meseguer, Av.
Marqués de los Vélez s/n, 30008 Murcia, Spain. E-mail: ocortes@um.es
Evaluation of autofluorescence and image of oral
pathogens and the tooth
Jong-Wook Kim, dds, ms, Jeong-Kil Park, dds, ms, phd, Franklin
Garcia-Godoy, dds, ms, phd, phd
Abstract: Purpose: To test the applicability of autofluorescence (AF)
spectrum and image in the detection and identification of oral pathogens. Methods: Oral pathogens (Candida albicans, Porphyromonas gingivalis, Streptococcus mutans) and teeth were used. To induce AF, the 405 nm
laser was used as a light source, and AF was obtained and observed using a
spectrometer, fluorescence camera, and microscope, respectively. Results: The tested oral pathogens had
similar spectral distributions, but their peak intensities and peak ratios were
different. Their peak positions and spectral patterns were different from those
of the tested sound and carious teeth. These differences were also found from
the other referenced oral mucosa. Fluorescence image could localize the
existence of oral bacteria. Oral pathogens could be imaged by fluorescence, but
identification of each pathogen by image was not probable. (Am J Dent 2022;35:212-216).
Clinical significance: Oral pathogens can be observed
and identified from the lesion if autofluorescence spectrum and fluorescence
images are combined.
Mail: Prof. Yong Hoon Kwon,
Department of Dental Materials, School of Dentistry, Pusan National University, Mulgeum-eup, Yangsan, 50612 S. Korea. E-mail: y0k0916@pusan.ac.kr
_______________________________________________________________________________________________________________________________________________________________
Review
Article
_______________________________________________________________________________________________________________________________________________________________
Does
laser treatment restore the bond strength of resin composites
Gang Niu, dds, ms, Ying-hui
Chen, dds, ms, Thomas
Attin, dr med dent & Hao
Yu, dds, phd, dr med dent
Abstract: Purpose: To do a systematic review and meta-analysis to determine
whether laser treatment affects the bond strength of resin composites to
recently bleached enamel. Methods: This report follows the Preferred
Reporting Items for Systematic Reviews and Qualitative Analyses (PRISMA)
statement. Medline via PubMed, Embase, Web of Science, and the Cochrane Library
databases were searched with no limits on publication year. Two reviewers independently
screened all titles and abstracts to perform the study selection, data
extraction, and risk-of-bias assessments. A random-effects meta-analysis model
was performed using Review Manager software (version 5.3, Cochrane
Collaboration). Results: From the 93 records
identified, seven articles that met all the inclusion criteria were included in
the systematic review, and six studies were included in the meta-analysis. The
overall results showed a statistically significant difference in bond strength
between the control group and laser-treated group (P= 0.04; mean difference:
5.27; 95% confidence interval: 0.28 to 10.27), favoring the laser-treated
group. Subgroup analyses revealed that the tooth source (bovine or human teeth)
contributed to the effect of laser treatment on the bleached enamel. (Am
J Dent 2022;35:178-184).
Clinical
significance: Laser treatment may increase the bond strength of resin
composites to recently bleached enamel. Pretreatment with a laser, preferably
with Nd:YAG (1 W, frequency of 10 Hz, irradiation time
of 60 seconds) or CO2 lasers (0.5 W, frequency of 10 Hz, irradiation
time of 60 seconds), may be recommended to restore the bond strength of recently
bleached enamel.
Mail: Dr. Hao Yu, Yangqiao Zhong Road 246, Fuzhou, China. E-mail:
haoyu-cn@hotmail.com
