^{December 2022 Abstracts}

 

 

 

In vitro comparison of bonding to zirconia- or glass- based ceramics between flowable resin composites and composite resin cements

 

Shiqi Dai, mds, Ying Chen, mds, Bingzhuo Chen, mds, Hongliang Meng, mds  &  Haifeng Xie, phd

 

Abstract: Purpose: To evaluate and compare the bonding of flowable resin composites and light-cured resin cements to dental ceramics. Methods: Grit-blasted zirconia plates were primed with MDP-containing adhesive. Lithium disilicate glasses plates were etched with HF and primed with silane. Two flowable resin composites with high (CM: 75 wt%/62 vol%) and low (BF: 67.3 wt%/47 vol%) filler contents, and two resin cements, again with high (C: 72 wt%/69 vol%) and low (R: 66 wt%/47 vol%) filler contents, were bonded to both types of pretreated ceramics. Shear bond strength (SBS) was measured after 24 hours water storage or 10,000 times thermocycling between 5 and 55°C. The viscosities and film thicknesses of the four resin-based luting agents (RBLAs) were also explored by rotational rheometer and metallurgical microscope severally. Results: Different RBLAs provided statistically different SBS values, with the high-filler specimens exhibiting higher SBS values than the low-filler specimens. The viscosities decreased in the order C > R > BF > CM. The film thicknesses for the BF and C groups were higher than those of the CM and R groups. (Am J Dent 2022;35:275-283).

 

 

 

 

 

Mail: Dr. Haifeng Xie, Department of Prosthodontics, Affiliated Hospital of Stomatology, Nanjing Medical University, Nanjing, China. E- mail: xhf-1980@126.com

 

 

 

In vivo vs. in vitro color stability of hybrid ceramic and resin nanoceramic blocks used for endocrowns: A new method

 

Nurullah Turker, dds, phd,  Deniz Yanık, dds, phd,  Fatma Güner, dds  &  Ulviye Sebnem Buyukkaplan, dds, phd

 

Abstract: Purpose: To evaluate and compare in vitro and in vivo color parameters of hybrid ceramic, resin nanoceramic, and artificial acrylic resin teeth. Methods: For the in vitro stages, 120 specimens (2 mm) were prepared from Vita Enamic (VE), Lava Ultimate (LU), CeraSmart (CS), and acrylic teeth (IV), and immersed in coffee, red wine, and distilled water for 24, 72, and 144 hours. For the in vivo stage, 16 individuals received a complete denture that had upper premolars made of VE, LU, CS blocks, and IV. The color was measured at 1, 3, and 6 months. Color difference (ΔE₀₀), translucency (TP), and contrast ratio (CR) were obtained using a spectrophotometer. Shapiro Wilk, one-way ANOVA, and repeated measures ANOVA were used for statistical analysis. Results: ΔE₀₀ of VE and LU were higher than CS and IV (P< 0.05). ΔTP of VE and LU were lower than CS and IV (P< 0.05). ΔTP of CS was higher in red wine compared to coffee. ΔCR of CS and IV were increased with prolonged immersion (P< 0.001). ΔE₀₀ and ΔCR were similarly affected in coffee and red wine. All discolorations were higher than clinical acceptability (ΔE₀₀> 1.77). For in vivo stages, ΔE₀₀ of VE and LU increased over time (P< 0.01). No difference was detected between in vivo and in vitro ΔE₀₀ of CS (P> 0.05). ΔE₀₀ of VE, LU, and IV was higher in in vitro stages. LU and VE showed lower color stability; their use in esthetic regions is questionable. The prolonged immersion increased discoloration. Coffee and red wine had a similar effect on discoloration and opalescence. Discoloration in laboratory conditions did not correspond to the clinical discoloration according to the new method presented in this study. (Am J Dent 2022;35:284-290).

 

 

 

 

 

 

Mail: Dr. D. Yanik, Cıplaklı, Akdeniz Blv. No: 290/A, 07190 Döşemealtı/Antalya, Turkey.  E-mail:  deniz.yanik@antalya.edu.tr

 

Influence of brushing with an antiseptic soap solution on the surface and biological properties of a hard chairside reline resin

 

Beatriz Ribeiro Ribas, msc, Camilla Olga Tasso, msc, Túlio Morandin Ferrisse, phd & Janaina Habib Jorge, phd

 

Abstract: Purpose: To evaluate the influence of brushing with a specific antiseptic soap solution on the surface (roughness and hardness) and biological properties of a specific hard chairside reline resin. Methods: The hard chairside reline resin specimens were made and distributed to the following groups according to disinfectant solution: sodium hypochlorite 0.5% (SH), Lifebuoy solution 0.78%; experimental group (LS) and phosphate-buffered saline PBS to be submitted to the brushing cycle for 10 seconds. The roughness and hardness were assessed before and after the cycle. For the biological properties, the colony-forming unit and Alamar Blue assays were performed. For all the properties evaluated the sample size consisted of nine specimens. The data were submitted to two-factor ANOVA (surface properties) and one-way ANOVA (biological properties) and Tukey's post-test with a significance level of 5% (α= 0.05). Results: The Lifebuoy group did not present a statistical difference (P> 0.05) in relation to the other groups for the evaluated surface properties. Furthermore, the Lifebuoy solution showed a statistically significant difference (P> 0.05) in relation to the negative control in the reduction of biofilm on the resin and no significant difference (P> 0.05) was observed when compared to the positive control group. Thus, it was concluded that brushing with the Lifebuoy soap solution did not interfere with the surface properties of the hard chairside reline resin, and was able to reduce the biofilm of C. albicans. (Am J Dent 2022;35:291-296).

 

 

 

 

Mail: Dr. Janaina Habib Jorge, Department of Dental Materials and Prosthodontics, School of Dentistry, São Paulo State University (UNESP), Rua Humaitá, 1680 Centro, Araraquara, SP, Brazil. E- mail: habib.jorge@unesp.br

 

Fracture resistance of endodontically treated premolars restored with CAD-CAM onlays

 

Günçe Ozan, dds, phd, Meltem Mert Eren, dds, phd, Benin Dikmen, dds, phd  &  Esra Yildiz, dds, phd

 

Abstract: Purpose: To evaluate the fracture resistance of endodontically treated premolars restored with CAD-CAM onlay restorations. Methods: 60 extracted mandibular first premolars were selected and at first divided into three groups regarding treatment options: MOD onlay with buccal cusp coverage, MOD onlay with buccal cusp coverage + endodontic treatment, MOD onlay with buccal cusp coverage + endodontic treatment + fiber post. Then, all groups were divided into subgroups (n=10) according to the restorative material used: IPS e.max CAD and Lava Ultimate. Each group was submitted to 5,000 thermal cycles, embedded in acrylic resin and secured in a universal testing machine respectively. A compressive load was applied until fracture, at a crosshead speed of 0.5 mm/minute. Statistical significance among each group was analyzed using one-way ANOVA and Bonferroni tests. Results: Statistically, endodontically treated IPS e.max onlays had numerically the lowest average fracture resistance [753.1 (± 224.9) N/mm²] among all treatment options. IPS e.max onlays treated with fiber posts had significantly higher resistance than that of endodontically treated IPS e.max CAD group (P= 0.013). Endodontically treated teeth restored with Lava Ultimate onlays [1,381.0 (± 471.7) N/mm²] showed significantly higher averages of fracture resistance than IPS e.max CAD onlays. (Am J Dent 2022;35:308-314).

 

 

 

 

 

 

Mail:  Dr. Günçe Ozan, Department of Restorative Dentistry, Faculty of Dentistry, Istanbul University, Fatih, Istanbul, Turkey.  E-mail:  gunce.saygi@istanbul.edu.tr

 

Bactericidal effect on S. mutans using N-TiO₂ with combined treatment of low concentration H₂O₂ and visible light

 

Seung-Yong Song, dds, ms, Franklin Garcia-Godoy, dds, ms, phd, phd, Yong Hoon Kwon, phd &  Jeong-Kil Park, dds, ms, phd

 

Abstract: Purpose: To test the feasibility of nitrogen-doped TiO₂ nanoparticles in the killing of Streptococcus mutans (S. mutans) for short term treatment. Methods: For the study, S. mutans were treated with the combinations of N-TiO₂, visible light, and without/with 0.5% H₂O₂ inclusion. Visible light was irradiated for 3 minutes one time. Results: Methylene blue solution was degraded (bleached) 5-30% by one of N-TiO₂ (or TiO₂) + visible laser (405 or 660 nm)+0.5% H₂O₂ conditions owing to almost linearly producing free radicals through photocatalysis. Antibacterial outcomes treated with N-TiO₂ were slightly better than those by TiO₂ regardless of test condition. Also, killing of S. mutans treated with 405 nm laser was slightly better than those by 660 nm laser. (Am J Dent 2022;35:315-318).

 

 

Mail: Professor Jeong-Kil Park, Department of Conservative Dentistry, School of Dentistry, Pusan National University, Mulgeum-eup, Yangsan, 50612 Korea. E-mail: jeongkil@pusan.ac.kr

 

 

Teeth whitening using nitrogen doped-TiO₂ nanoparticles and hydrogen peroxide under visible light irradiation

 

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

 

Abstract: Purpose: To test the efficacy of nitrogen doped-TiO₂ (N-TiO₂) nanoparticles (NPs) on teeth whitening under visible light irradiation. Methods: N-TiO₂ NPs were prepared by the sol-gel method, using TiN as a precursor. Their light absorbance and crystal structures were characterized. Photocatalytic reactions were tested using methylene blue (MB) and extracted teeth. For the extracted teeth, carbomer gel, without or with 3% H₂O₂, and light irradiated, with subsequent evaluation of the color differences. Results: Unlike ordinary TiO₂, N-TiO₂ showed high absorbance after 400 nm. N-TiO₂ prepared with TiN as a precursor showed rutile phase over the TiN structure. For MB solution, N-TiO₂ with 3% H₂O₂ showed the maximum decrease in absorbance after laser irradiation. Observing the effect on teeth, N-TiO₂+3% H₂O₂+405 nm laser treatment achieved approximately 25% higher whitening than that by 15% H₂O₂ during the same treatment time. Higher H₂O₂ concentrations may offer faster results. (Am J Dent 2022;35:319-322).

 

 

 

 

Mail: Dr. Franklin Garcia-Godoy, Department of Bioscience Research, College of Dentistry, University of Tennessee Health Science Center, 875 Union Avenue, Memphis, Tennessee, 38163, USA. E-mail: fgarciagodoy@gmail.com

 

 

Development of an in vitro biofilm formation model for screening anti-periodontal disease agents

 

Tomoko Tanaka, dds, phd  &  Tetsuro Horie, phd

 

Abstract: Purpose: To devise a method for artificial biofilm formation using Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, and Streptococcus gordonii, as well as a method for evaluating the effects of various ingredients on the artificial biofilm. Methods: An artificial biofilm was developed using P. gingivalis, T. forsythia, T. denticola, and S. gordonii, which was then observed using scanning electron microscopy and evaluated by microflora analysis. The artificial biofilm was exposed to chlorhexidine gluconate and stained with a fluorescent dye. Then, the fluorescent-stained biofilm was observed using a confocal laser microscope and measured using a fluorescent microplate reader. Results: The microflora analysis confirmed that the culture medium developed was capable of culturing four different bacterial species at the same time. The distribution of dead bacteria differed according to the difference in the concentration of exposed chlorhexidine gluconate. Moreover, the rate of attachment of viable cells decreased in a concentration-dependent manner. Many bacteria were detached from the biofilm in the group exposed to 0.09% chlorhexidine gluconate. Exposure to chlorhexidine gluconate induced a concentration-dependent decrease in living microorganisms and an increase in dead microorganisms in the biofilm. (Am J Dent 2022;35:323-328).

 

 

 

 

Mail: Dr. Tomoko Tanaka, Department of Oral Health, The Nippon Dental University School of Life Dentistry at Tokyo, 1-9-20 Fujimi, Chiyoda-ku, Tokyo, 102-8159, Japan.  E-mail: t-tanaka@tky.ndu.ac.jp

 

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                                                                                                                                Review Article

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Novel findings on anti-plaque effects of stannous fluoride

 

Tao He, phd, dds,  Yuanshu Zou, phd, Joe DiGennaro, ms  &  Aaron R. Biesbrock, dmd, phd, ms

 

Abstract: Purpose: To evaluate the antiplaque effects for 0.454% bioavailable gluconate chelated stannous fluoride (SnF₂) dentifrices versus controls by clinical model, plaque index, tooth surface and tooth type in a pooled analysis. Methods: Randomized controlled trials (RCTs) were conducted to evaluate plaque effects of SnF₂ dentifrices from the same formulation family over the past 30 years. Forty-four 4-day and longer-term (≥ 2 weeks) RCTs conducted in six countries with 3,336 subjects using Turesky Modified Quigley-Hein Plaque Index, Rustogi Modification of the Navy Plaque Index, Digital Plaque Imaging Analysis, and Silness and Lӧe Plaque Index were included. Results: In 13 and 11 longer-term studies assessing SnF₂ dentifrice versus a negative or positive control, respectively, standardized differences in average plaque score of -1.15 (95% CI: -1.61, -0.69) and -0.74 (95% CI: -1.20, -0.28) were observed (P ≤ 0.011), favoring SnF₂. Reductions represented a 19% and 16% benefit versus the negative and positive control, respectively. In 18 and five 4-day studies assessing SnF₂ dentifrice versus a negative (NaF/SMFP) or positive (triclosan/chlorhexidine) control, respectively, differences in average 4-day plaque score of -0.27 (95% CI: -0.31, -0.23) and -0.15 (95% CI: -0.25, -0.06) were observed (P≤ 0.001) favoring SnF₂. Reductions represented a 14% and 11% benefit versus the negative and positive control, respectively. Significant antiplaque benefits for SnF₂ dentifrice were seen regardless of clinical model, plaque index, tooth surface or type, including brushed and unbrushed surfaces (P≤ 0.049). (Am J Dent 2022;35:297-307).

 

 

Mail: Dr. Aaron Biesbrock, The Procter & Gamble Company, 8700 Mason-Montgomery Road, Mason, OH 45040, USA. E- mail: biesbrock.ar@pg.com