^{April 2021 Abstracts}

 

 

 

 

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Effects of whitening toothpaste and bleaching treatment on resin composite discoloration caused by cigarette smoke and electronic vapor aerosol

 

Xiaoyi Zhao, dds, phd, Filippo Zanetti, phd, Linchuan Wang, DDS, PhD, Hans Malmstrom, dds,  Shoaib Majeed, ms, Manuel C. Peitsch, phd,  Julia Hoeng, phd  &  Yanfang Ren, dds, phd, mph

 

Abstract: Purpose: To compare the effects of whitening toothpaste and bleaching with 6% hydrogen peroxide (H₂O₂) on discoloration of dental resin composite caused by cigarette smoke (CS) and electronic vapor product (EVP) aerosol. Methods: 40 resin composite discs were divided into three groups: 15 each for CS and EVP aerosol exposure and 10 for air exposure (control). Exposures were performed for 15 days, with daily brushing with regular toothpaste. Two whitening sessions, including 21 days of brushing with whitening toothpaste and 3 days of treatments with take-home bleaching (6% H₂O₂), were performed after the exposure. Color and gloss were assessed before exposure, at every 5 days of exposure, and after each whitening session. Results: After 15 days of exposure, marked discoloration of resin composite was observed in the CS group (ΔE = 23.66 ± 2.31), minimal color change in the EVP group (ΔE = 2.77 ± 0.75), and no color change in the control group. Resin composites exposed to CS did not recover their original color after treatment with whitening toothpaste (ΔE = 20.17 ± 2.68) or take­home bleaching (ΔE = 19.32 ± 2.53), but those exposed to EVP aerosol reverted to baseline after treatment with whitening toothpaste (ΔE = 0.98 ± 0.37), and no further change in color was observed following take­home bleaching. The gloss of resin composites exposed to CS, EVP aerosol, and air decreased equally with exposure time. Brushing with whitening toothpaste recovered the gloss similarly in all groups, but no further change was observed following take-home bleaching. (Am J Dent 2021;34:63-69).

 

 

 

 

 

 

Mail: Dr. Yanfang Ren, University of Rochester Eastman Institute for Oral Health, 625 Elmwood Ave. Rochester, NY 14620, USA. E-mail: yanfang_ren@urmc.rochester.edu

 

 

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Effect of two desensitizing agents applied previous to in-office bleaching on the degree of whitening and dentin sensitivity: A randomized, controlled, double-blind clinical trial

 

Carlos Eduardo Misiak Godoy, dds, msc, Simonides Consani, dds, msc, phd, Ana Tereza Bittencourt Guimarães, dds, msc, phd Brenda Matsunaga Laurindo, dds, msc, Marcio José Mendonça, dds, msc, phd  &  Veridiana Camilotti, dds, msc, phd

 

Abstract: Purpose: To evaluate the effect of two desensitizing agents applied before in-office bleaching, on the degree of whitening and dentin sensitivity. Methods: Participants were randomly assigned to the groups, according to the desensitizing agent used, with n=10 for each one. The bleaching was performed with 35% hydrogen peroxide, divided according to the desensitizing agent used prior to the bleaching procedure: Placebo (PL); Desensibilize KF with potassium nitrate and 0.2% sodium fluoride (PN); and Oxa-Gel with potassium oxalate (PO). The level of color saturation was assessed at the beginning of treatment and after 1 week of its completion by means of comparative method with the aid of a color scale. The degree of sensitivity (DS) was noted by the subjects with the aid of a visual scale throughout the time that the bleaching agent remained in contact with the teeth (5, 10, 15, 20, 25 and 30 minutes) as well as 1, 24 and 48 hours after the end of application. Pain and the degree of color saturation were evaluated using the Shapiro-Wilk test. The DS was assessed by Kruskal-Wallis and Dunn’s tests. The color was evaluated by ANOVA and Tukey’s HSD. Results: There was no significant difference in the degree of bleaching among the groups. DS was significantly more accentuated in the 48-hour period. The DS was significantly higher for the PL group and significantly lower for the PO group. The desensitizing agents reduced the DS without affecting the effectiveness of the bleaching treatment. (Am J Dent 2021;34:70-74).

 

 

Mail: Dr. Veridiana Camilotti, State University of Western Paraná, School of Dentistry, Universitária Avenue, no 1619 – Universitário, Cascavel, Paraná, Brazil, 85819-110. E-mail: vericamilotti@hotmail.com

 

 

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Spectrophotometric evaluation of the efficacy of natural versus commercial bleaching agents

 

Shivani Kohli, mds, mfds rcps (glasgow), MFDS RCS (Edinburgh), Afaf Al-Haddad, phd,  Amanda Yan Yin Siew, dds, Woon Lai Nam, dds,  Husna Dayana Binti Hamdan, dds  &  Qistina Amani Binti Roslan, dds

 

Abstract: Purpose: To compare the bleaching efficacy of in-office (Opalescence), professional home (LumiBrite), over the counter (WhiteLight) and natural (strawberry extract) bleaching agents. Methods: 80 teeth were selected and divided into two groups which were stained with black coffee and red wine respectively. The stained specimens were subdivided into four subgroups to be bleached with Opalescence, LumiBrite, WhiteLight and strawberry extract. Color measurements were made using spectrophotometer at baseline level, after staining, after bleaching and 1 week after bleaching. The ∆E₀₀ was calculated post bleaching (∆E₀₀1), after 1-week follow up (∆E₀₀2) and color changes between 1-week follow up and baseline (∆E003). Data were analyzed by paired t-test and ANOVA with a significant difference of P< 0.05. Results: Paired t-test showed significant differences in ∆E₀₀1 and ∆E₀₀2 for both stained specimens (P< 0.001). For black coffee stained specimens, Whitelight had significantly higher ∆E₀₀2 compared to the other bleaching agents (P< 0.05). For red wine stain, Whitelight also showed the significantly lowest ∆E₀₀1 (P< 0.001) and the highest ∆E₀₀2 (P< 0.001) compared to other groups. LumiBrite showed the significantly lowest ∆E₀₀3 for red wine stained specimens (P< 0.05). Whitelight had the poorest bleaching efficacy with deterioration effect after 1-week follow up. Opalescence, LumiBrite and strawberry extract had clinically perceptible and comparable bleaching efficacy. Strawberry extract appeared to be a potential natural bleaching agent with a desirable effect. (Am J Dent 2021;34:75-79).

 

 

Mail: Dr. Shivani Kohli, Division of Clinical Dentistry, School of Dentistry, International Medical University, Kuala Lumpur, Malaysia. E-mail: ShivaniKohli@imu.edu.my

 

 

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Effect of double layer application on bond durability of universal adhesives to proximal dentin-cementum gingival margins

 

Ashraf I. Ali, bds, msd, phd, Hoda S. Ismail, bds, msd  &  Franklin Garcia-Godoy, dds, ms, phd, phd

 

Abstract: Purposes: To evaluate and compare the effect on micro-tensile bond strength (μTBS) of a double layer application of three universal adhesives applied in self-etch mode to proximal dentin/cementum gingival margins of class II direct composite restorations, immediately and after 12 months water storage. Methods: 66 molars with compound class II cavities, with gingival margin 1 mm below CEJ, were divided into three groups according to the universal adhesive used. The adhesives evaluated included All-Bond Universal (AB), Single Bond Universal (SB), and Prime&Bond Elect (PB). The groups were further subdivided according to adhesive application technique, either single layer or double layer application. All teeth were restored with the same nanofilled resin composite. μTBS were examined at a crosshead speed of 0.5 mm/minute after 24 hours or 12 months water storage. Fracture mode was assessed under stereomicroscope. Data were analyzed by two-way analysis of variance (ANOVA) followed by Tukey’s post hoc test (P< 0.05). Results: The double layer application μTBS values were significantly higher than single layer application in all groups. Regardless of the type of adhesive or application technique, all subgroups showed significantly decreased bond strength after aging. There were significant lower μTBS values for AB adhesive compared with the other two adhesives that demonstrated no significant differences between them. The double layer application technique was effective in enhancing μTBS values of all tested adhesives bonded to proximal dentin/cementum gingival margins compared to single layer application. Regardless of application technique, all tested adhesives were incapable of defying long-term water aging. (Am J Dent 2021;34:80-86)

 

 

 

 

Mail: Dr. Hoda Saleh Ismail, Department of Operative Dentistry, Faculty of Dentistry, Mansoura University, Algomhoria Street, PO Box 35516, Mansoura, Egypt. E-mail: hoda_saleh@mans.edu.eg

 

 

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A clinical study to assess the gingivitis reduction efficacy of a novel stannous-containing fluoride dentifrice

 

Zhipeng Xu, mds,  Tao He, dds, phd,  Yanyan He, ms,  Phil Fei, ms,  Lily Sun, ms,  Yamei Chen, bs  &  Jiahui Li, bs

 

Abstract: Purpose: To assess the gingivitis reduction efficacy of a novel stannous-containing fluoride dentifrice relative to a negative control. Methods: 100 generally healthy adults with 10 or more gingival bleeding sites based on the Mazza Modification of the Papillary Bleeding Index (Mazza GI) were enrolled into a 2-week randomized, controlled, double-blind, single-center, two-treatment, parallel group clinical study. The subjects were randomly assigned to the stannous-containing dentifrice group (experimental group) or the sodium fluoride dentifrice group (negative control group). An oral examination and Mazza GI examination were conducted at Baseline, Day 3 and Week 2 post-baseline by a qualified dental examiner. Results: 98 subjects completed the study. The experimental group provided a significant reduction in Mazza GI scores and number of bleeding sites relative to baseline at Day 3 and Week 2 (P< 0.0001). The negative control did not provide significant reductions versus baseline for either measure at either timepoint (P> 0.3). At Day 3, the experimental group provided a statistically significant reduction of Mazza GI scores and number of bleeding sites compared with the negative control group (P< 0.0001). At Week 2, the experimental group showed 24.11% lower Mazza GI scores and 54.81% fewer bleeding sites than the negative control group (P< 0.0001). (Am J Dent 2021;34:87-90).

 

 

 

 

Mail: Zhipeng Xu, Shaanxi Provincial People’s Hospital No. 256 Youyi West Road 710068 Xi’an, Shannxi, China. E-mail: sxkq88@163.com

 

 

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Biaxial flexural strength of various CAD-CAM glass-ceramic materials

 

Layali  Alakkad, bds, msc,  Aikaterini  Kostagianni, dmd, dds, msc,  Matthew Finkelman, phd, Ahmed  Maawadh, bds, msc dscd,  Ala  Ali, bds, msc, dsc, dmd  &  Aikaterini Papathanasiou, dmd, dds

 

Abstract: Purpose: To evaluate and compare the flexural strength of three CAD-CAM glass-ceramic materials and to investigate the effect of various surface treatments on their flexural strength. Methods: 120 rectangular specimens were fabricated from three different types of CAD-CAM ceramic blocks and were divided into three groups: zirconia-reinforced lithium silicate (Celtra Duo, Group 1), leucite-reinforced glass-ceramic (IPS Empress CAD, Group 2), and lithium disilicate ceramic (IPS e.max CAD, Group 3). Dimensions of the specimens were standardized to 14.5×12.5 mm and 1.5 mm thickness. Specimens in each group were randomized into four subgroups. The first subgroup (NS) did not undergo any surface treatment; the second subgroup (P) underwent polishing only; the third subgroup (G) underwent glazing only; and the fourth subgroup (PG) underwent both polishing and glazing surface treatments. Biaxial flexural strength (FS) testing was performed until fracture occurred; FS was calculated in MPa. All analyses were performed using SPSS version 24. Results: Group NS2 showed the lowest FS (89.34 ± 25.30 MPa). Group PG3 showed a significantly higher FS (365.38 ± 52.52 MPa) than Group P3 (268.15 ± 48.34). There was a statistically significant difference among the material groups for each surface treatment: IPS e.max CAD showed the highest FS, which was significantly greater than that of both Celtra Duo and IPS Empress CAD. The combination of polishing and glazing surface treatment resulted in significantly higher flexural strength than polishing alone for all three materials tested. For each material, no significant difference was found between the following surface treatments: control and polishing-only surface treatments; glazing-alone and the combination of polishing and glazing surface treatments. For each surface treatment, Celtra Duo showed significantly lower flexural strength than IPS e.max CAD. However, it displayed higher flexural strength than IPS Empress CAD, although the difference was only significant for glazing and the combination of polishing and glazing. (Am J Dent 2021;34:91-96).

 

 

 

 

Mail: Dr. Aikaterini Papathanasiou, Department of Prosthodontics, Tufts University School of Dental Medicine, 1 Kneeland Street, Suite 221, Boston, MA 02111, USA. E-mail: Aikaterini.Papathanasiou@tufts.edu

 

 

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Periodontal disease in acute coronary syndrome patients

 

Ying Gu, dds, phd,  Lorne M. Golub, dmd, msc, dsc, mdsc(h), FNAI,  Hsi-Ming Lee, phd,  Wei Hou, phd &  Maria E. Ryan, dds, phd

 

Abstract: Purpose: This pilot study assessed the periodontal status and biomarkers of systemic inflammation in acute coronary syndrome (ACS) patients. Methods: 15 ACS patients on statin (anti-cholesterol) therapy, were recruited into the study an average of 9 months after discharge from university hospital. Blood and mouthrinse samples were collected for analysis of inflammatory biomarkers including high sensitivity C-reactive protein (hsCRP), IL-6, IL-1β, TNF-α, and MMP-9. Full-mouth periodontal examination, including pocket depth (PD), clinical attachment levels (CAL), bleeding on probing (BOP), and tooth mobility, was performed. Results: When their periodontal status was assessed by CAL, 100% of these statin-treated ACS patients exhibited moderate (66.7%) to severe (33.3%) periodontal disease, which appears to be higher than the rate described for the general adult population (i.e., 47% for periodontitis). In addition, (1) their blood hsCRP levels ranged from 0.94 to 12.6 mg/L with a mean of 3.41 mg/L, which is considered high risk for cardiovascular disease (CVD) in spite of their statin therapy, and (2) the data demonstrated a positive correlation between severe periodontitis and elevated blood hsCRP levels (P< 0.05), consistent with systemic inflammation. (Am J Dent 2021;34:97-100).

 

 

Mail: Dr. Ying Gu, Department of General Dentistry, School of Dental Medicine, Stony Brook University, Stony Brook, NY 11794-8706, USA. E-mail:ying.gu@stonybrook.edu

 

 

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Reliability of magnetic resonance imaging on detecting degenerative bone changes of the temporomandibular joint

 

Juliane Piragine Araujo, dds, phd, Marcelo Eduardo Pereira Dutra, dds, phd, Alan Motta Canto, dds, msc &  Jefferson Xavier Oliveira, dds, phd

 

Abstract: Purpose: To evaluate and describe the most frequent TMJ degenerative bone alterations on MRI and CT and to determine the accuracy, sensitivity, and specificity of MRI. Methods: Images of 80 subjects were selected and evaluated from a database and 57 were selected. The subjects were submitted to CT and MRI exams (each subject on the same day). The joints were evaluated in the sagittal and coronal planes under closed mouth position. Each individual parameter was scored as absent or present. Absolute and relative frequencies were obtained and the Kappa concordance index test and equality of two proportions were used. To correlate the presence of bone alterations, the Chi-Square test was performed. A significance level of 0.05 (5%) was defined, with 95% of statistical confidence interval. Results: Of the 57 subjects, (47 female, 10 male), the ages ranged from 18-83 years (mean 43 years). The intra and inter-rater agreement tests demonstrated reliability among the examiners for all variables analyzed on MRI and CT. (Am J Dent 2021;34:101-104).

 

 

Mail: Dr. Juliane Piragine Araujo, Discipline of Oral Radiology, Department of Stomatology, School of Dentistry, University of Sao Paulo, Av. Professor Lineu Prestes 2227, Butanta, São Paulo, SP, 05508-000, Brazil. E-mail: ju_piragine@hotmail.com

 

 

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Effect of phosphorylated chitosan and carbodiimide biomodification on the chemical composition of eroded dentin

 

Mirian Saavedra Lopes Ururahy, msd, phd,  Fabiana Almeida Curylofo-Zotti, dds, msd, phd, Gustavo Teodoro Costa Lizarelli,  Arlete Barbosa dos Reis, phd,  Ana Paula Ramos, phd &  Silmara Aparecida Milori Corona, msd, phd

 

Abstract: Purpose: To evaluate the chemical composition and morphological properties of eroded dentin after biomodification with phosphorylated chitosan (P-Chi) and carbodiimide (EDC). Methods: 42 bovine dentin specimens were used; 21 of these specimens were subjected to erosive challenge with 0.3% citric acid (pH = 3.2) for 2 hours. The specimens were randomly divided into six groups according to dentin substrate (sound or eroded) and biomodification [with 2.5% P-Chi, with 0.5 mol/L EDC, or no biomodification (control)]. The specimens were analyzed by Fourier-transform infrared spectroscopy (FTIR, n= 5, in triplicate) and atomic force microscopy (AFM, n= 2) to verify the phosphate, carbonate, and organic matrix absorption peaks and to investigate surface morphology, respectively. The data were analyzed with Origin 6.0. Results: Dentin erosion reduced the intensity of the phosphate (1,100 cm^-1) and carbonate (872 cm^-1) related bands, which evidenced demineralization. Eroded dentin consisted of a more irregular surface containing slightly more open tubules. Modification with P-Chi removed intertubular dentin, which was compatible with surface demineralization; however, this modification obliterated dentin tubules. EDC did not promote demineralization. Biomodified dentin had a more irregular surface, irrespective of substrate type. (Am J Dent 2021;34:105-109).

 

 

 

 

Mail: Prof. Silmara Aparecida Milori Corona, Department of Restorative Dentistry, School of Dentistry of Ribeirão Preto, University of São Paulo, Av. do Café, Ribeirão Preto - SP, 14040-904, Brazil. E-mail: silmaracorona@forp.usp.br

 

 

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Randomized clinical trial assessing anti-gingivitis efficacy of two stannous fluoride dentifrices and zinc/arginine dentifrice

 

Tao He, dds, phd, Sigal Mazor, mph, dmd, Yuanshu Zou, phd,  Julie Grender, phd,  Svetlana Farrell, dds, phd, Paul Sagel, bsche,  Aaron R. Biesbrock, dmd, phd, ms,  Hans Timm, phd  &  Avi Zini, dmd, mph, phd

 

Abstract: Purpose: To evaluate the anti-gingivitis efficacy of two bioavailable stannous fluoride (SnF₂) dentifrices versus a zinc/arginine dentifrice and a negative control dentifrice, and to compare the plaque control benefits. Methods: This was a single-center, randomized, controlled, four-treatment, parallel-group, double-blind, 3-month clinical trial. Healthy adult subjects with gingivitis were randomly assigned to one of four different dentifrice treatment groups: SnF₂ dentifrice A, SnF₂ (1,100 ppm F) + sodium fluoride (350 ppm F) + sodium hexametaphosphate (Procter & Gamble); SnF₂ dentifrice B, SnF₂ (1,100 ppm F) + sodium fluoride (350 ppm F) + citrate (Procter & Gamble); Zn/Arg dentifrice, zinc/arginine + sodium fluoride (1,450 ppm F) (Colgate-Palmolive); negative control dentifrice, sodium monofluoro-phosphate (1,000 ppm F) + sodium fluoride (450 ppm F) (Colgate-Palmolive). Subjects brushed with their assigned treatment dentifrice and an assigned manual toothbrush (Oral-B Indicator) for 1 minute, twice daily, for the duration of the study. Gingivitis was assessed at Baseline and at Weeks 2, 4 and 12 by calculating the total number of gingival bleeding sites using the Gingival Bleeding Index, and plaque was assessed at Baseline and at Week 12 using the Turesky Modified Quigley-Hein Index. A repeated measures model was carried out across Weeks 2, 4, and 12 to determine bleeding efficacy (total number of bleeding sites). An ANCOVA with baseline plaque as the covariate was used to evaluate plaque efficacy at Week 12. Results: 161 subjects were randomized (mean age= 38.8 years). 154 subjects completed the study and 153 had evaluable data at Week 12. The mean (SD) number of Baseline bleeding sites overall was 78.74 (31.16) with no significant difference between groups (P= 0.537). SnF₂ dentifrice A significantly reduced the number of bleeding sites relative to the negative control dentifrice at Weeks 2, 4 and 12 by 15.4%, 13.7% and 17.2%, respectively. SnF₂ dentifrice B significantly reduced the number of bleeding sites relative to the negative control dentifrice at Week 4 by 13.9% (P= 0.041). Relative to the Zn/Arg dentifrice, SnF₂ dentifrice A produced significantly greater reductions in gingival bleeding sites at Weeks 2, 4 and 12 by 23.4%, 17.2% and 20.9%, respectively (P≤ 0.007). SnF₂ dentifrice B produced significantly greater bleeding reductions versus the Zn/Arg dentifrice at Weeks 4 and 12 by 17.4% and 14.4%, respectively (P≤ 0.035). The Zn/Arg dentifrice did not differ significantly in the number of bleeding sites (P≥ 0.127) or plaque (P= 0.175) relative to the negative control dentifrice. Both SnF₂ dentifrices significantly reduced plaque levels (P≤ 0.029) relative to both negative control dentifrice and Zn/Arg dentifrice at Week 12. All dentifrices were well tolerated. (Am J Dent 2021;34:110-115).

 

 

Mail: Dr. Tao He, The Procter & Gamble Company, 8700 Mason-Montgomery Road, Mason, OH, 45040, USA. E-mail: he.t@pg.com

 

 

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Radiant-exposure attenuation through Class-2 proximal slots

 

Dave D. Kojic, dmd, md, phd,  Omar El-Mowafy, bds, phd,  Olesya Falenchuk, phd,  Christopher J. Felix, bsc, Rafael Francisco Lia Mondelli, dds, ms, phd   &  Juliana Fraga Soares Bombonatti, dds, ms, phd

 

Abstract: Purpose: To determine the extent of radiant exposure (RE) attenuation of three LED light-polymerization units (LPUs), and their beam-profile, at the bottom of the Class-2 slot, using MARC-PS. Methods: 10 seconds RE was delivered to MARC-PS’ anterior sensor by Bluephase-Style, Demi-Plus, and Deep-Cure-S. Two ivorine lower first-molars received Class-2 proximal box preparations: (3´2´4 mm and 4´4´4 mm) and were sectioned horizontally above the cementoenamel junction. Tofflemire matrix-retainer was placed around each tooth and secured with a low-fusing compound. Each LPU tested delivered 10 seconds RE to MARC-PS through proximal slots. Mean RE of three readings per group was obtained. Data were analyzed using Pearson correlation, mixed ANOVAs with a pre-set alpha of 0.05. Results: RE attenuation ratio calculated from the baseline to 4´4´4/3´2´4 Class-2 boxes were: 58.25/80.03 Bluephase-Style; 49.36/80.25 Demi-Plus; 32.8/77.43 Deep-Cure-S. A significant and strong correlation (r= 0.86, P< 0.001) between the reduction in aperture size and RE was found. The beam profile of LED-LPUs tested decreased RE values at the bottom of a proximal box. More than 80% RE value reduction from the baseline to the smallest Class-2 cavity 3´2´4 aperture was observed. (Am J Dent 2021;34:116-119).

 

 

Mail: Dr. Dave D. Kojic, Department of Restorative Dentistry, Faculty of Dentistry, University of Toronto, 124 Edward Street, Rm 350B, Toronto, Ontario M5G 1G6, Canada. E-mail: dave.kojic@utoronto.ca