
_______________________________________________________________________________________________________________________________________________________________
Research
Article
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Effect of fiber post materials and timing
of coronal preparation
Chen Qu, mm & Xiangling Liao, md
Abstract: Purpose: To examine the effects of fiber
post material and coronal preparation timing on the sealing ability of
post-core systems and to determine whether these factors interact under thermal
and mechanical aging conditions. Methods: A 2×2 factorial design was
used. 60 freshly extracted single-rooted premolars meeting predefined inclusion
and exclusion criteria were randomly assigned to four groups (n= 15):
fiber-reinforced composite (FRC) post with immediate preparation, FRC with
delayed preparation, prefabricated quartz fiber (PQF) post with immediate
preparation, and PQF with delayed preparation. Post space length was
standardized to 10 mm while maintaining a 4 mm apical seal, in accordance with
the recommendation that post length should approximate two-thirds of root
length and at least equal the clinical crown height. All procedures were
completed by a single prosthodontist. Specimens underwent 5,000 thermal cycles
followed by 240,000 cyclic loading cycles. Interfacial microgap width was serially evaluated by SEM at two time points, namely after
thermocycling and after cyclic loading, and the data were analyzed with a
linear mixed-effects model. Results: Post material type (F= 45.32, P<
0.001, η²p= 0.43) and time point (F= 312.56, P< 0.001, η²p= 0.84)
showed significant effects, as did the material×time interaction (F= 8.73, P=0.004, η²p= 0.13). Preparation timing was not
significant (F= 2.15, P= 0.148). After thermocycling, group B showed smaller microgap width than group D (3.91± 0.87 vs. 5.62± 1.77 μm; mean difference, -1.71 μm;
95%CI: -2.76 to -0.66; P=0.003). After cyclic loading, Group A was smaller than
Group C (13.97± 1.89 vs. 17.85± 2.83 μm; mean
difference, -3.88 μm; 95%CI: -5.62 to -2.14;
P< 0.001), and Group B was smaller than group D (8.84± 1.98 vs. 13.29± 2.85 μm; mean difference, -4.45 μm;
95%CI: -6.22 to -2.68; P< 0.001). No root fractures were detected during
specimen preparation, thermocycling, or cyclic loading. (Am J Dent 2026;39:166-172).
Clinical
significance: For a given fiber post material,
immediate and delayed coronal preparation produced comparable marginal sealing.
Compared with prefabricated quartz fiber posts, fiber-reinforced composite
post-core systems provided superior interfacial stability after aging and may
be preferable in roots with irregular or flattened canal morphology.
Mail: Dr. Xiangling Liao, Department of Stomatology, Beijing Luhe Hospital Affiliated to Capital Medical University, No. 82 Xinhua South Road, Tongzhou District, Beijing 101149, China. E-mail: liaoxiangling114@163.com
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Research
Article
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Fibromyalgia and
acute periapical abscesses
Ilan
Rotstein, dds & Joseph Katz, dmd
Abstract: Purpose: This cross-sectional study was to
assess the prevalence of acute PAs in fibromyalgia patients. Methods: Nine years of data from 2,108,676 patients were retrieved and analyzed by
searching corresponding ICD-10 diagnosis codes for fibromyalgia and acute PAs.
The odds ratio (OR) for acute PAs and their association with fibromyalgia were
calculated and statistically analyzed using MEDCALC software at the 95%
confidence level. Logistic regression and adjustment for diabetes, nicotine
dependence, and alcohol use disorder comorbidities were done. Results: Overall, the OR for acute PAs in patients with fibromyalgia was 4.7, and the
difference in prevalence compared to the total hospital patient population was
statistically significant (P< 0.0001). After adjustment for diabetes, the OR
was 2.8. After adjustment for nicotine dependence, the OR was 2.6. After
adjustment for alcohol related disorders, the OR was 4.4. The difference in
prevalence compared to the total hospital patient population remained
statistically significant (P< 0.0001). (Am J Dent 2026;39:173-176).
Clinical significance: Clinicians should be aware of the possible higher
prevalence of periapical abscesses in patients with fibromyalgia. More frequent
dental visits for caries control and pulp disease prevention are warranted.
Mail: Dr. Ilan Rotstein, Department
of Endodontics and Periodontics, University of Southern California, 925 West
34th Street, Suite 310, Los Angeles, CA 90089-0641, USA. E-mail:
ilanrotstein@gmail.com
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Research
Article
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Oral malodor
control with a stabilized stannous fluoride toothpaste
Dutmanee Seriwatanachai, phd, Terdphong Triratana, dds, Luis R. Mateo, ma, Robert D’Ambrogio, bsc
Abstract: Purpose: To evaluate the clinical efficacy
of a test toothpaste containing 0.454% stannous fluoride stabilized with zinc phosphate as compared to a
control fluoride toothpaste containing 0.76% sodium monofluorophosphate on oral malodor reduction via organoleptic scores after 3 weeks of twice daily
product use. Methods: A randomized, single-center, double-blind,
parallel-group clinical trial conducted in Bangkok, Thailand. Eighty adult
subjects with qualifying baseline oral malodor scores were randomized to use
either the test toothpaste or the control toothpaste twice daily for 3 weeks.
Efficacy was assessed using the organoleptic hedonic scale (1-9) by four
calibrated judges. The primary endpoint was the reduction in organoleptic
scores assessed 12 hours post-brushing (overnight). Results: All 80
subjects completed the protocol. At baseline, there were no significant
differences in organoleptic scores between groups (P= 0.816). After 3 weeks,
the Test group showed a 37.8% reduction from baseline in overnight malodor
scores (P< 0.001), while the Control group showed a 13.6% reduction (P<
0.001). The Test group demonstrated a statistically significant (P< 0.001)
28.0% greater reduction in oral malodor compared to the Control group. No
adverse events were reported. (Am J Dent 2026;39:177-180).
Clinical significance: The 0.454%
stannous fluoride toothpaste stabilized with zinc phosphate provided a
superior, long-lasting solution for overnight oral malodor management compared
to a standard sodium monofluorophosphate toothpaste
after 3 weeks of use.
Mail: Dr.
Yun-Po Zhang, Colgate-Palmolive Co., 909 River Rd., Piscataway, NJ 08854, USA. E-mail:
yun_po_zhang@colpal.com
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Research
Article
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Effects on
adjacent enamel and dentin of restorations
Bettina Gabriela Ferreira do Amaral, dds, Leonardo Santos Barros, dds, msc,
Abstract: Purpose: This study evaluated the cross-sectional Knoop
microhardness (KHN) of enamel and dentin adjacent to restorations made with
bioactive materials, and their surface degradation after pH cycling. Methods: Molar blocks (n=10) were restored with conventional resin composite (RC;
Z350XT), resin-modified glass-ionomer cement (R-GIC; Vitremer),
flowable compomer (FC; Twinky), resin composite with
S-PRG filler (RC-S-PRG; Beautifil II), or self-curing
bioactive composite (RC-SP; Cention N). After pH
cycling, KHN was measured at 100, 200, and 300 µm from the restoration margins
and at depths of 20, 40, and 60 µm from the surface. Surfaces were evaluated
using scanning electron microscopy (SEM). Data were analyzed via split-plot
ANOVA and Tukey’s test (α=0.05). Results: Regardless of material,
enamel KHN was lower at 20 µm than at 60 µm depth (100 µm distance), at 40 µm
than at 60 µm depth (300 µm distance), and dentin KHN was also lower at 20 µm.
RC and R-GIC showed reduced dentin KHN at 20 µm compared to 60 µm. SEM analysis
revealed surface degradation in all materials
(RC<R-GIC<FC<RC-S-PRG<RC-SP). (Am J Dent 2026;39:181-186).
Clinical significance: The
ion-releasing bioactive materials did not provide superior protection of
microhardness compared with the conventional composite. Moreover, bioactive
materials exhibited greater surface degradation after acidic challenge, which
may compromise their long-term stability in the oral environment.
Mail: Dr.
Waldemir Francisco Vieira-Junior, Piracicaba Dental School, University of
Campinas, Av. Limeira, 901 - CEP 13414-903, Piracicaba, SP, Brazil. E-mail: waljr@unicamp.br
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Research
Article
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Effect of
faucet-mounted water filters on the fluoride
Ahmed S. Aljuaid, bds, msd, sbrd, Armando E.
Soto-Rojas, dds, mph, Laila Al Dehailan, bds, msd, phd,
Abstract: Purpose: To evaluate the effect of
faucet-mounted water filters (FMWF) on the fluoride and calcium concentrations
in tap water during their use. Methods: A convenience sample of 15
different brands of FMWF was investigated (PUR, Brita, Waterdrop, Culligan, Engdenton, DuPont, Instapure, iSpring, OEMIRY, IVO, SJ WAVE, WINGSOL, ZeroWater, AIBERLE,
MIST). Water samples were collected before the installation and after removal
of the filters to determine baseline fluoride and calcium values. After
mounting the filters, samples were collected after 1, 5, 10, 30, 50, 75, and
100 liters of water passed through each filter. Fluoride analysis was performed
using a fluoride ion-specific electrode (Orion #96-909-00), while calcium
analysis was performed using atomic absorption spectrometry. The data were
analyzed using one-sample t-tests and one-way ANOVA. Results: The study
found significantly lower fluoride and calcium levels (P< 0.05) in water
filtered through PUR, Brita, and AIBERLE filters than in unfiltered water,
whereas water filtered through Waterdrop, WINGSOL, and MIST filters had higher
levels of fluoride and calcium. Overall, the differences between filtered and
unfiltered water were minor for fluoride (up to 4% reduction) but more substantial
for calcium (up to 25% reduction). (Am J Dent 2026;39:187-192).
Clinical significance: The evaluated faucet-mounted water filters do not
affect fluoride concentrations in tap water and thus the effectiveness of
community water fluoridation in a clinically significant manner; however, some
filters may reduce calcium concentrations significantly.
Mail: Dr. Frank Lippert, Department
of Biomedical and Applied Sciences, Oral Health Research Institute, Indiana
University School of Dentistry, 415 Lansing St., Indianapolis, IN 46202 USA. E-mail: flippert@iu.edu
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Research
Article
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Effect of office
bleaching on the color change and roughness of leucite
Zahide
Aydin, dds, Çağla Yeşil, dds & Zeynep Yeşil, dds, phd
Abstract: Purpose: To evaluate in the laboratory the effect of an in-office
whitening agent on color change, translucency, and surface roughness of
leucite-reinforced CAD-CAM material with different surface finishes exposed to
different beverages [cola, tea, fruit juice, coffee, distilled water
(Control)]. Methods: All the IPS Empress CAD-CAM ceramic block specimens
were treated with a glaze layer (n=75) and then randomly divided into three
groups. The samples (n=25) in Group 1 (Control) were not treated (glaze layer remained).
The glaze layer of the other samples (n=50) was abraded by the same researcher.
While the samples in Group 2 were treated with Optrafine (Optrafine after glazing) (n=25), those in Group 3
were subjected to surface treatment with Eve polishing kits (Eve kit after
glazing) (n=25). The samples were then immersed in five different beverages
(cola, coffee, tea, fruit juice and distilled water) (n=5) and clinic-type
bleaching was applied. Color measurements were recorded by spectrophotometer
and surface roughness (Ra) values were recorded by profilometer. Color change (DE00)
values were calculated using the CIE2000 formula. The data were statistically
analyzed using Shapiro-Wilk test, ANOVA and Bonferroni test (P< 0.05). Results: Regardless of the surface finishing process and beverage, the mean values of
color change (DE00) did not differ
according to time (P= 0.148). As a result of the ANOVA, surface finishing
process, beverage, and time interaction were found to be very significant
(P< 0.001). Regardless of the surface finishing process and beverage, it was
determined that the mean roughness values differed according to time (P=
0.019). (Am J Dent 2026;39:193-200).
Clinical significance: Although bleaching glass ceramic restorations with
bleaching agents containing 40% hydrogen peroxide was effective to remove
stains, maintaining the glaze surface finish is critical for color stability
and surface integrity of CAD-CAM ceramics.
Mail: Prof.
Dr. Zeynep Yeşil, Ataturk University, Faculty of Dentistry, Department of
Prosthodontics, Erzurum, Turkey. E-mail: zyesilz@hotmail.com
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Research
Article
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Influence of the amount
of dentifrice used for brushing on enamel
Shaira Rahielah Kasi, dds, Rafaela Oliveira
Pilecco, dds, phd, Lucas
Saldanha da Rosa, dds, phd,
Abstract: Purpose: To investigate whether the amount
of dentifrice (dose) used per brushing affects the abrasion of the hard tooth
tissues. Methods: Enamel and dentin specimens were subjected to
simulated brushing with two commercial dentifrices (Prodent, Smyle dentifrice in tablet form) and positive as well
as negative controls at varying amounts of dentifrices (standard dose, half,
and double dose). Brushing without dentifrice (with water) functioned as a
negative control. Tooth wear was quantified using profilometry, and statistical
analysis was performed using one-way ANOVA and Tukey’s post hoc test (α= 0.05). Results: For enamel, dose variations had minimal impact. However, dentin
wear increased significantly with higher doses, particularly for the positive
control and Smyle at double dose (P< 0.05).
Dilution reduced abrasivity inconsistently across
brands. (Am J Dent 2026;39:201-205).
Clinical significance: The amount of dentifrice used for brushing has a
significant, dose-dependent effect on dentin abrasion, whereas enamel is
relatively unaffected, and brushing without dentifrice does not cause wear. While
dentifrice in tablet form provides a manufacturer‑defined standard amount
per brushing, this is not the case for dentifrice in paste form. Because the
amount of dentifrice used influences dentin wear, it is advisable that
manufacturers clearly define the recommended quantity of dentifrice for a
single brushing.
Mail: Prof. Albert Feilzer,
Department of Dental Materials and Reconstructive Oral Care, Academic Center
for Dentistry (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam,
Gustav Mahlerlaan 3004, 1081LA Amsterdam, The Netherlands. E-mail: a.feilzer@acta.nl
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Research
Article
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Perioperative
nursing based on the Knowledge-Attitude-Practice theory
Meiling
Shen, mm, Yi Feng, bs, Xinwen Peng, bs, Yan Chen, bs, Tong Cheng, bs, Kangwen Yang, bs
Abstract: Purpose: To investigate the clinical effectiveness of
perioperative nursing interventions based on the Knowledge–Attitude–Practice
(KAP) theory in patients undergoing robot-assisted dental implant surgery. Methods: A total of 54 patients who underwent robot-assisted dental implant surgery were
allocated to either a conventional perioperative care group (control group) or
a KAP intervention group. The control group received routine perioperative care
according to the hospital’s standard protocols, whereas the intervention group
received perioperative care based on the KAP theory in addition to the standard
care. The KAP-based care followed a progressive pathway characterized by
knowledge dissemination, attitude cultivation, and behavioral guidance. The
intervention period lasted for 8 weeks. Primary outcome measures included
self-care ability, negative emotions, postoperative swelling and pain,
follow-up compliance, and patient satisfaction. Results: After 8 weeks,
the intervention group exhibited significantly greater improvements in all
domains of self-care behavior (regular follow-up, correct toothbrushing, and
balanced diet) as well as in total self-efficacy scores compared with the
control group. Dental anxiety and dental fear scores decreased significantly in
both groups, with greater reductions in the intervention group. Postoperative
pain scores were significantly lower and satisfaction scores significantly
higher in the intervention group. At 3 and 6 months, compliance rates in the intervention
group were significantly higher than those in control group. (Am J Dent 2026;39:206-210).
Clinical
significance: Perioperative nursing based on the
Knowledge–Attitude–Practice (KAP) theory enhanced self-care ability, alleviated
negative emotions, increased long-term follow-up compliance, and improved
patient satisfaction in individuals undergoing robot-assisted dental implant
surgery. This model effectively standardizes patient care behaviors and
optimizes postoperative recovery.
Mail: Ms. Jianfang Huang, School & Hospital of Stomatology, Wuhan University, No. 237 Luoyu Road, Hongshan District,
Wuhan City, Hubei Province, 430000 China. E-mail: huangjianfang@whu.edu.cn
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Research
Article
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The impact of
different cavity design parameters on intraoral scanner
Yunus Emre
Ozden, dds, phd, Idil Ozden, dds, Zeynep Ozkurt Kayahan, dds, phd
Abstract: Purpose: To evaluate the effects of
different tooth structure thicknesses and cavity depths on the accuracy of
intraoral scanners (IOS) in endocrown restorations. Methods: A mandibular typodont model was used, with the left mandibular first molar
replaced by an extracted real human tooth. Endocrown cavities with varying depths (3.5 mm and 5 mm) and remaining wall thicknesses
(1.5 mm and 0.5 mm) were prepared. Master models were scanned using a
high-precision extraoral scanner, and the data were exported in STL format. Ten
intraoral scans were performed for each group using the Trios 3 IOS. Scanning
accuracy was analyzed using the Root Mean Square (RMS) value for trueness and
the Interquartile Range (IQR) for precision in Geomagic Design X software. The
differences in RMS values among the groups were examined using Independent
Samples T test and one-way ANOVA test. Results: Significant differences
in RMS and IQR values were observed between groups with different cavity depths
and remaining tooth structure thicknesses (P< 0.001). Groups with thinner
remaining tooth structures and deeper cavities exhibited greater deviations,
indicating reduced scanning accuracy. (Am J Dent 2026;39:191-196).
Clinical significance: Cavity depth and tooth structure thickness
significantly influenced the accuracy of intraoral scanners in endocrown restorations.
Mail: Dr. Idil Ozden, Basibuyuk Road Marmara University, Health Campus 9/3, 34854 Maltepe, Istanbul, Turkey. E-mail: idil.akman94@gmail.com