^{April 2026 Abstracts}

Oral cleansing effect of sugar-free chewing gum with sodium hexametaphosphate and xylitol

 

Minmin Tian, phd,  Michael W.J. Dodds, bds, phd,  Li Chen, bs,  Yue Sun, ms,  Elif Apaydin, ms,  De-Yu Hu, dds, phd &  Zhi Zhou, dds

 

Abstract: Purpose: To investigate the effect of sugar-free gum (SFG) with xylitol and sodium hexametaphosphate (SHMP) on oral cleansing by in vitro tests and a human clinical trial. Methods: Hydroxyapatite (HA) discs were pre-treated with SHMP and evaluated for inhibition of stain formation caused by infusion of black tea in vitro. Subsequently, the effect of SFG formulated with different levels of SHMP was determined using a laboratory chewing apparatus to establish effective dosage of SHMP. Stain levels in both tests were assessed by colorimetry to determine L*, a*, b* values. Finally, a 12-week randomized, single blind, parallel arm human clinical study was performed to test effects of xylitol gum with SHMP on clinical indices of stain (Lobene Stain Index) and plaque (Plaque Index). 195 subjects were enrolled, with 181 subjects completing the trial. Results: In vitro pre-treatment of HA discs with SHMP significantly inhibited tea-induced stain. Results from the chewing machine study showed that gums with SHMP significantly inhibited stain formation at 7 and 14 days, with a minimum effective level of 16.5 mg. The clinical study showed that SFG with 50% xylitol and 0.5% SHMP significantly inhibited plaque after 12 weeks compared with baseline and no-gum control (P< 0.05). The test gum also demonstrated a significant reduction of stain formation compared with baseline, no-gum control and commercial gum after 12 weeks (P< 0.05), reducing surface stain by 34% compared with baseline (P< 0.05). It was concluded that sugar-free gum containing xylitol and a low level of SHMP can provide an effective oral cleansing benefit, adjunctive to regular toothbrushing. (Am J Dent 2026;39:54-60).

 

 

Mail: Dr. Minmin Tian, Mars Wrigley, 1132 West Blackhawk Street, Chicago, IL 60642, USA. E-mail: Minmin.tian@effem.com

 

 

 

Laboratory evaluation of the erosive potential of fluoride-free mouthwashes using a dental erosion simulation model

 

Astrid Carolina Valdivia-Tapia, dds, msc, phd,  Anderson Takeo Hara, dds, msd, phd, Jaime Aparecido Cury, dds, msc, phd,  Antonio Pedro Ricomini-Filho, dds, msc, phd  &  Frank Lippert, msc, phd

 

Abstract: Purpose: To investigate the enamel/dentin surface loss caused by acidic fluoride-free mouthwashes using dental erosion simulation model. Methods: Enamel and dentin bovine slabs (n=8) were subjected to 5 days of treatment (four 1-minute mouthwash treatments/day). Six fluoride-free mouthwashes (MW1–MW6) with varying pH (3.03-5.12) were tested. Three 0.3% citric acid solutions (pH 3.0-5.0) and deionized water served as controls. Surface loss (SL) was measured using non-contact profilometry; enamel hardness was assessed via Knoop microhardness. Data was analyzed using one-way ANOVA. Results: For both substrates, the model was able to differentiate between the controls. Differences between PC5 and NC (0.06± 0.11/-0.13± 0.28) were only directional for enamel. SL ranged considerably between MW1-MW6; however, all were less erosive than PC3 in both substrates. In enamel, MW1 (0.20± 0.12), MW3 (-0.26± 0.29), and MW6 (0.01± 0.12) were not different from NC. MW4 (-0.48± 0.29) was not different from PC4 and PC5, whereas MW5 (-1.19± 0.59) was more erosive than PC5. The SL data for dentin were mostly comparable to enamel. In dentin, MW1 (-0.34± 0.30), MW3 (-0.68± 0.45), and MW6 (-0.79± 0.17) were also not different from NC. Some fluoride-free mouthwashes may cause dental hard tissue erosion, particularly in dentin. Erosive potential appeared to be influenced more by composition than by pH alone. (Am J Dent 2026;39:61-65).

 

 

 

 

Mail: Dr. Astrid C. Valdivia-Tapia, Oral Health Research Institute, School of Dentistry, Indiana University, 415 Lansing St, Indianapolis, IN 46202, USA. E-mail: acvaldiv@iu.edu

 

 

Effect of whitening toothpastes on enamel color and surface roughness: A laboratory study

 

Ecehan Kaplan, dds, Ayşe Dündar, dds, phd  &  Çağatay Barutçugil, dds, phd

 

Abstract: Purpose: This laboratory study evaluated the effect of toothpastes with different whitening mechanisms on the color change and surface roughness of human enamel. Methods: 40 human maxillary incisors were sectioned at the cemento-enamel junction using a water-cooled saw. Crowns were embedded in cold acrylic with vestibular surfaces facing down. After polishing with silicon carbide papers, samples were stored in distilled water for 24 hours, then immersed in coffee solution for 6 days. Specimens were rinsed and divided into five groups (n=8): Group 1 (control), Group 2 (RSW: ROCS Sensation Whitening), Group 3 (SWN: Signal White Now Gold), Group 4 (COW: Colgate Optic White Charcoal), Group 5 (OW: Opalescence Whitening). Color was measured with a VITA Easyshade spectrophotometer, and surface roughness with a profilometer. Data were analyzed using ANOVA and Tukey HSD (P= 0.05). Results: All groups exhibited color changes above the perceptual threshold (ΔE₀₀ > 1.8). The control group had the lowest ΔE₀₀ value, and RSW had the highest, followed by COW, with no significant difference between them (P> 0.05). Surface roughness was not significantly different between groups (P> 0.05). (Am J Dent 2026;39:66-72).

 

 

 

 

Mail: Dr. Ecehan Kaplan, Department of Restorative Dentistry, Faculty of Dentistry, Antalya Bilim University, 07040, Antalya, Turkey. E-mail: ecehank@hotmail.com

 

 

Clinical efficacy of a stannous fluoride toothpaste stabilized <with zinc phosphate in reducing supragingival calculus formation compared to a sodium monofluorophosphate toothpaste: A randomized controlled trial

 

Dutmanee Seriwatanachai, phd,  Petcharat Kraivaphan, dds, Cholticha Amornchat, Terdphong Triratana, dds,  Luis R. Mateo, ma,  Robert D’Ambrogio, bsc  &  Yun-Po Zhang, phd, dds (hons)

 

Abstract: Purpose: To evaluate the comparative clinical efficacy of a test toothpaste containing 0.454% stannous fluoride stabilized with zinc phosphate as compared to a regular fluoride toothpaste containing 0.76% sodium monofluorophosphate in controlling supragingival calculus formation over a 12-week period. Methods: A randomized, single-center, double-blind, parallel-group study was conducted in Bangkok, Thailand. Healthy adults (n= 100) with a baseline Volpe-Manhold Calculus Index score ≥7.0 were randomized to either the stannous fluoride (Test) or sodium monofluorophosphate (Control) group. After a dental prophylaxis, subjects brushed twice daily for 12 weeks. Supragingival calculus was assessed using the Volpe-Manhold Calculus Index. The primary efficacy endpoint was the comparison of baseline-adjusted mean calculus scores at 12 weeks, analyzed using ANCOVA. Results: 97 subjects completed the study. At 12 weeks, the Test Group had baseline adjusted mean Volpe-Manhold score of 11.47, while the Control Group had a score of 17.48. The Test Group demonstrated a statistically significant 34.4% (P< 0.001) less supragingival calculus formation compared to the Control Group. (Am J Dent 2026;39:73-76).

 

 

 

Mail: Dr. Yun-Po Zhang, Colgate-Palmolive Co., 909 River Rd., Piscataway, NJ 08854, USA.  E-mail: yun_po_zhang@colpal.com

 

 

Effects of pediatric syrups on surface roughness and Streptococcus mutans adhesion to restorative materials

 

Mihriban Gökcek Taraç, ds, phd  &  Meryem Çolak, dds, phd

 

Abstract: Purpose: To evaluate the effects of two commonly used pediatric medical syrups on the surface roughness and the adhesion of Streptococcus mutans (S. mutans) to three fluoride-releasing restorative materials: high-viscosity glass-ionomer, polyacid-modified resin composites, and giomer. Methods: The 90 prepared specimens for surface roughness test and 90 specimens for microbial adhesion test were divided into three groups by simple random method for each material (n= 30) and then into three subgroups (n= 10) based on the immersion medium: Augmentin, Calpol, or distilled water. Specimens underwent twice-daily immersion for 2 minutes to simulate routine drug administration followed by storage in artificial saliva (pH 6.8), which was refreshed daily over a 14-day period. Surface roughness and S. mutans adhesion were measured before and after the immersion cycle. Mixed ANOVA was applied to examine the effects of the materials and solution subgroups on surface roughness within the time factor framework. Multiple linear regression was applied to investigate the effects of the materials and solution subgroups on microbial adhesion within the time factor framework. To evaluate the relationship between surface roughness and microbial retention, Spearman’s correlation analysis was applied. Results: Augmentin caused a significant increase in surface roughness of polyacid-modified resin composites (P= 0.019), and giomer (P= 0.044), in addition Calpol caused a significant increase for polyacid-modified resin composites (P= 0.0148). High-viscosity glass ionomer had the greatest resistance to surface degradation. Augmentin consistently exhibited the highest microbial adhesion across all material groups except distilled water-GIC group. Calpol (P= 0.002) and distilled water (P< 0.001) also showed a significant increase in microbial adhesion. Giomer was the most resistant material to time-dependent microbial adhesion, whereas glass-ionomer was the most susceptible restorative material. An increase in surface roughness positively correlated with increased microbial adhesion in all material groups. (Am J Dent 2026;39:77-84).

 

 

 

 

 

 

 

Mail: Dr. Mihriban Gökcek Taraç, Karabuk University Demirçelik Kampüsü Faculty of Dentistry Merkez/Karabük, Turkey. E-mail: gokcekmihriban@karabuk.edu.tr

 

 

Surface roughness and surface microhardness of bulk-fill and conventional resin composites after erosive-abrasive cycles: A laboratory study

 

Leyla Devletli Ozyigit, dds  &  Guneş Bulut Eyuboglu, dds, phd

 

Abstract: Purpose: To investigate comparatively the changes in surface roughness and surface microhardness of resin composites applied with traditional incremental layering technique and bulk-fill resin composites after erosive/abrasive applications. Methods: In this laboratory study, three conventional resin composites with different contents: Filtek Z250 (FZ), Filtek Ultimate (FU), Clearfil Majesty Esthetic (CME), and four bulk-fill resin composites: X-tra fil (VXF), Filtek One Bulk Fill (FOB), QuiXfil (QXF), and Tetric N-Ceram Bulk Fill (TNC) were used. While preparing the test specimens, resin composites were applied to 8 mm diameter and 2 mm height round plexiglass molds (n= 15) and polymerized. Each specimen was polished. Then, the baseline surface roughness (R0) and surface microhardness (H0) values of the specimens were measured. Each group had been exposed erosive/abrasive cycle for 10 days. After the cycle, by measuring the roughness (R1) and microhardness (H1) values of the specimen, the alterations of the surface properties were investigated. After the baseline and erosive/abrasive cycles of the specimens, the surface analyses were performed with scanning electron microscopy. One-way ANOVA test, Tukey's post hoc test, and t-test were used for statistical analysis. Differences at the P< 0.05 level were considered statistically significant. Results: There was no statistically significant difference between the H0 values of the FU, VXF, QXF, and FZ groups, and the H0 values of these groups were higher than the other groups (P< 0.05). After the erosive/abrasive cycle, there was no significant difference in the H1 values of only the FZ and VXF groups (P> 0.05). When the R0 values were examined, there was no significant difference between the FOB, FU, FZ, and TNC groups (P> 0.05), and the R0 values of these groups were statistically lower than the other groups (P< 0.05). A statistically significant increase was observed in the R1 values of all composite materials examined after erosive/abrasive applications (P< 0.05). In the SEM findings, erosive/abrasive applications caused degradation of both the organic matrix and surface properties of inorganic fillers. (Am J Dent 2026;39:85-94).

 

 

Mail: Dr. Leyla Devletli Ozyigit, Department of Restorative Dentistry, School of Dentistry, Karadeniz Technical University, Ortahisar/Trabzon, Turkey. E-mail: leyladevletli@gmail.com

 

 

 

 

Effects of polishing systems on surface properties and color stability of 3D-printed resin restoratives

 

Mehmet Can Ararat, dds,  Engin Saçu, dds,  Satılmış Ürgün, phd,  Sinan Fidan, phd, Mustafa Özgür Bora, phd  &  Neslihan Tekçe, dds, phd

 

Abstract: Purpose: To evaluate the effects of different polishing systems on surface roughness (Ra, Rz, Sa), water contact angle and color stability (ΔE₀₀) of a 3D printed permanent resin material. Methods: 50 specimens were fabricated using a Saremco Print Crowntec resin with 3D printer and divided into five equal groups: Control (No treatment); Sof-Lex XT; Diacomp Plus Twist; Optiglaze Color Clear; and Ultradent Diamond Polish. Surface roughness was evaluated using a 3D non-contact profilometer, and surface morphology was examined by scanning electron microscopy (SEM). Contact angle was measured using the sessile drop method and analyzed with software. Color change was measured by a spectrophotometer after 15 days of storage in coffee solution. Data were compared by one-way ANOVA and Tukey post hoc test (α= 0.05). Results: Optiglaze showed significantly higher Ra and Rz values than the other polishing systems (P< 0.05). The Ra value of the Diacomp Plus Twist group was lower than the Diamond Polish group; the Sa value was higher than the Sof-Lex XT and Diamond Polish groups (P< 0.05). The Diacomp Plus Twist group exhibited a higher water contact angle than the Optiglaze and Diamond Polish groups (P< 0.05). Sof-Lex XT showed higher ΔE₀₀ compared to other polishing systems (P< 0.05). All polishing groups showed lower parameter values than the control group (P< 0.001). (Am J Dent 2026;39:95-100).

 

 

 

 

Mail: Dr. Mehmet Can Ararat, Department of Restorative Dentistry, Faculty of Dentistry, Kocaeli University, Pasadag, Akcakesme 7, Basiskele, Kocaeli, Turkey, 41190.  E-mail: mehmetcanararat2@gmail.com

 

 

Bleaching of stained teeth using Cu-coupled TiO₂ nanoparticles using hydrogen peroxide and blue light

 

Byeong Jin Gu, dds, ms, Sungae Son, dds, ms, phd, Jeong-Kil Park, dds, ms, phd, Yong Hoon Kwon, phd &  Franklin Garcia-Godoy, dds, ms, phd, phd

 

Abstract: Purpose: To evaluate the efficacy of copper-doped titanium dioxide (Cu-TiO₂) nanoparticles (NPs) in bleaching the stained teeth when subjected to hydrogen peroxide (H₂O₂) and blue light irradiation. Methods: Cu-TiO₂ NPs were synthesized by mixing TiO₂ and Cu, followed by calcination. Their light absorbance was measured. Photocatalytic reactions were evaluated using methylene blue (MB), 3,3′,5,5′-tetramethylbenzidine (TMB), and terephthalic acid (TA) assays. Color changes in stained teeth were monitored under various conditions, including the presence or absence of 3% H₂O₂ and light irradiation. Additionally, the cytotoxicity of Cu-TiO₂ NPs on normal oral cells (periodontal ligament fibroblast: PDLF) was evaluated. Results: Unlike pristine TiO₂, Cu-TiO₂ exhibited a slightly increased absorbance in the 600-800 nm range due to the incorporated Cu. Cu-TiO₂ demonstrated high MB degradation and a marginal increase in peak intensity at 650 nm upon combined H₂O₂ and light irradiation. The TA assay showed a gradual increase in peak fluorescence intensity near 425 nm with increasing light exposure. Stained teeth treated concurrently with Cu-TiO₂ NPs, 3% H₂O₂, and laser irradiation exhibited significantly superior color changes. Importantly, the tested Cu-TiO₂ NPs displayed negligible toxicity to PDLF at concentrations up to 500 ppm. (Am J Dent 2026;39:101-104).

 

 

 

 

Mail: Dr. Franklin Garcia-Godoy, Department of Bioscience Research, College of Dentistry, University of Tennessee Health Science Center, 875 Union Avenue, Memphis, TN 33163, USA. E-mail: fgarciagodoy@gmail.com

 

 

Evaluation of bactericidal efficacy of modified TiO₂ nanoparticles via combined hydrogen peroxide and blue light irradiation

 

Hyeong Sun Park, dds, ms, Franklin Garcia-Godoy, dds, ms, phd, phd  &  Yong Hoon Kwon, phd

 

Abstract: Purpose: The present study evaluated the enhanced antibacterial efficacy against Enterococcus faecalis (E. faecalis) of modified titanium dioxide (TiO₂) nanoparticles when combined with hydrogen peroxide (HP) and blue light irradiation. Methods: Commercial pure TiO₂ was modified with polymer and copper to create polymer-copper-TiO₂ (pvpCT) nanoparticles. The optical property of pvpCT was characterized by absorbance measurements. Radical production was spectroscopically assayed using methylene blue (MB) degradation and terephthalic acid (TA) fluorescence. The antibacterial efficacy was then assessed against E. faecalis under blue light irradiation. Results: Unlike pure TiO₂, pvpCT exhibited a distinct absorbance after 400 nm and presented a dark yellow visual appearance, indicating successful modification. The combined treatment of pvpCT, HP, and 405 nm laser irradiation resulted in significantly higher MB degradation and a strong fluorescence peak near 425 nm from the TA assay, outperforming HP-only (up to 15%) or laser-only treatments. Crucially, this synergistic condition (pvpCT+HP+blue light irradiation) also achieved a remarkable elimination of E. faecalis. These findings suggest that the combination of pvpCT, HP, and blue light irradiation represents a promising and effective strategy for advanced antibacterial treatment in dental applications. (Am J Dent 2026;39:105-108).

 

 

 

 

 

Mail: Prof. Yong Hoon Kwon, Department of Dental Materials, School of Dentistry, Pusan National University, Yangsan 50612, Korea.  E-mail:  y0k0916@pusan.ac.kr