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                                                                                                                                 Research Article

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Comprehensive analysis of bacterial flora of a biofilm model in initial

caries-inducing environment

 

Masato Ishizawa, dds,  Kiyoshi Tomiyama, dds, phd,  Haruhiko Hasegawa, dds, phd,  Nobushiro Hamada, dds, phd  &  Yoshiharu Mukai, dds, phd

 

Abstract: Purpose: To analyze changes in pH and bacterial flora with duration of culture and timing of sugar supply using a polymicrobial biofilm model. Methods: The biofilm was prepared using the method of Exterkate et al. Stimulated saliva from an adult was collected on a glass slide and added to unbuffered McBain medium containing 0.2% sucrose and cultivated under anaerobic conditions for 10 hours. Cultivation continued anaerobically in saliva-free medium refreshed twice daily, with or without sucrose, in five groups: in the Control and Groups A and C, with 0.2% sucrose for 96, 192 and 288 hours, respectively; in Groups B and E, with 0.2% sucrose for 96 hours then, respectively, without for 96 and 192 hours; in Group D, with 0.2% sucrose for 96 hours, without for 96 hours, then with for 96 hours. The pH of all spent medium was measured. Total bacteria counts were determined by Q-PCR. The bacterial composition was determined by next-generation sequencing of 16S rDNA. Results: The pH of spent medium depended on the presence or absence of sucrose. Total bacteria counts were higher in A, C and D than the other groups, and markedly lower in Group E. Principal components analysis and cluster analysis showed wider variation of bacterial flora of the biofilm in Groups B, D and E than other groups. (Am J Dent 2020;33:55-58).

 

 

Mail: Dr. Kiyoshi Tomiyama, Division of Restorative Dentistry, Department of Oral Interdisciplinary Medicine, Graduate School of Dentistry, Kanagawa Dental University, 82 Inaoka-cho, Yokosuka, Kanagawa 238-8580, Japan.  E-mail: tomiyama@kdu.ac.jp

 

 

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                                                                                                                                 Research Article

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Effect of dental restorative materials surface roughness on the in vitro

biofilm formation of Streptococcus mutans biofilm

 

Paulina Contreras-Guerrero dds, msc, Marine Ortiz-Magdaleno, dds, msc, phd, Manuel Salvador Urcuyo-Alvarado, dds, Juan Antonio Cepeda-Bravo, dds, msc, Diana Leyva-del Río, dds, msc, José Elías Pérez-López, phd, Gabriel Fernando Romo-Ramírez, dds, msc &  Luis Octavio Sánchez-Vargas, dds, msc, phd

 

Abstract: Purpose: To evaluate Streptococcus mutans biofilm formation over different restorative dental materials. Methods: Using a bioreactor over 72 hours, four commercially available ceramics were evaluated: IPS E-max Press, IPS E-max CAD, Lava Ultimate CAD-CAM, Vita Enamic and two resin composites (SR Nexco Paste and Brilliant NG). The results were evaluated using atomic force microscopy and confocal microscopy, the biofilm was stained and the arbitrary fluorescence units (AFU) quantified. Results: The results showed that IPS E-max CAD had the lowest roughness values (4.29±1.79 nm), while the highest values were observed for Vita Enamic discs (77.13±17.35 nm). Analysis of S. mutans biofilm formation by AFU revealed lower values for IPS E-max CAD (6.77±1.67 nm); the highest values were found for Lava Ultimate (79.99±22.23 nm). Regarding the composite groups, SR Nexco Paste showed roughness values of 15.07±2.77 nm and lower arbitrary fluorescence units of 30.92±12.01 nm than Brilliant NT. There was a correlation between the surface roughness of ceramics and composite with S. mutans biofilm forma-tion. (Am J Dent 2020;33:59-63).

 

 

Mail: Dr. Luis Octavio Sánchez Vargas, Biochemical and Microbiology Laboratory, Faculty of Stomatology, Autonomous University of San Luis Potosí, Av. Dr. Manuel Nava #2, Zona Universitaria, 78290, S.L.P. México.  E-mail: octavio.sanchez@uaslp.mx

 

 

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                                                                                                                             Research Article

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Biomimetic strategy to stabilize the mechanical properties of caries-affected dentin matrix: A 12-month in vitro study

 

Carina S. Castellan, dds, ms, phd  &  Ana K. Bedran-Russo, dds, ms, phd

 

Abstract: Purpose: To evaluate the effect of dentin biomodification on the long-term strength of sound and caries-affected (CA) dentin as a strategy to stabilize the dentin matrix. The biomodification strategy utilized a naturally occurring proanthocyanidin-rich Vitis vinifera grape seeds (Vv), and compared with glutaraldehyde (GD). Methods: Dentin from sound and carious human molars were sectioned from mid-coronal dentin. The temperature denaturation (Td) was assessed using differential scanning calorimetry in sealed pans. The inhibitory effect of the agents on the activity of recombinant MMP-2 and -9 were assessed using colorimetric assay. The ultimate tensile strength (UTS) of demineralized dentin were determined 24 hours after treatment and after 12 months storage in simulated body fluid. Data were statistically analyzed using ANOVA and post-hoc tests (α= 0.05). Results: There was no statistically significant difference in the Td between sound and CA dentin (P= 0.140); however, Vv and GD significantly increased the Td of both substrates (P< 0.001), indicating formation of collagen cross-linking. The activity of MMP-2 and MMP-9 were reduced by Vv and GD in a concentration dependent manner. The UTS of dentin matrix was significantly affected by treatments and storage times (P< 0.001). After a 12-month period, a significant decrease in UTS was observed for sound and CA, with complete solubilization of the CA dentin matrix. Vv and GD stabilized the UTS of both dentin substrates (P< 0.05). Sound and CA dentin matrix were susceptible to degradation after the 12-month period. Degradation of dentin matrix due to endogenous proteases activity was more pronounced in CA dentin. Dentin biomodification strategies increased the thermal stability and enhanced the long-term mechanical properties of both sound and CA dentin matrix. (Am J Dent 2020;33:64-68).

 

 

 

 

 

 

Mail: Dr. Ana K. Bedran-Russo, Department of Restorative Dentistry, College of Dentistry, University of Illinois at Chicago, 801 South Paulina Street, Room 531, Chicago, IL, 60612, USA.  E-mail: bedran@uic.edu

 

 

 

 

 

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                                                                                                                                      Research Article

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Evaluation of a novel instrument for placement of dental sealants

 

Colette W. Stewart, rdh, msol,  Brian R. Morrow, ms  &   Franklin Garcia-Godoy, dds, ms, phd, phd

 

Abstract: Purpose: To evaluate marginal seal, adaptation, surface texture, and bubble presence of pit and fissure sealants when using a novel instrument (C-Shape It) or the manufacturers’ supplied applicators for sealant placement into occlusal fissures. Methods: Extracted molars with occlusal fissures were cleaned with pumice slurry and divided into six groups (n= 10/gp); three treatment and three control. Sealant materials placed included Ultraseal, Delton, and Helioseal. Excess water was removed per manufacturers’ instructions. Sealants were applied with each applicator and with the C-Shape It to each group from cusp to cusp without covering marginal ridges, and the polymerization guidelines for photocuring were followed for all the groups. Samples were thermocycled at 500× between 5° and 55°C. Teeth were sectioned in a buccolingual direction with a minimum of four sections per tooth and examined under a light microscope at 50× and scored. Results: Marginal seal, adaptation, penetration ability, surface texture, bubble formation and location of the sealants were analyzed using two-way ANOVA on ranks with a 95% confidence interval. The C-Shape It instrument showed consistently smoother surface texture (P< 0.001), which was statistically significant versus all manufacturers’ applicators for all materials. Bubble presence was statistically significantly less with the instrument C-Shape It versus the manufacturers’ applicators for all materials (P< 0.001). Results also revealed significant differences in marginal sealant adaptation. (Am J Dent 2020;33:69-73).

 

 

Mail: Ms. Colette W. Stewart, Department of Bioscience Research, College of Dentistry, University of Tennessee Health Science Center, 875 Union Avenue, Memphis TN, 38163, USA. E-mail: cstewa32@uthsc.edu

 

 

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                                                                                                                                     Research Article

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Comparison of occlusal wear between bulk-fill and conventional flowable resin composites

 

Maho Ujiie, dds, Akimasa Tsujimoto, dds, phd, Wayne W. Barkmeier, dds, ms, Carlos A. Jurado, dds, ms, Jose Villalobos-Tinoco, dds, Toshiki Takamizawa, dds, phd, Mark A. Latta, dmd, ms  &  Masashi Miyazaki, dds, phd

 

Abstract: Purpose: To investigate the occlusal wear of bulk-fill and conventional flowable resin composites. Methods: Four bulk-fill flowable resin composites: (1) Filtek Bulk Fill Flowable Restorative (FB); (2) G-ænial Bulk Injectable (GB); (3) SDR Flow+ (SD); and (4) Tetric EvoFlow Bulk Fill (TB), and four conventional flowable resin composites: (1) Clearfil Majesty IC (CM); (2) Filtek Supreme Ultra Flow (FF); (3) G-ænial Universal Flow (GF); and (4) Herculite XRV Ultra Flow (HF) were evaluated. Localized wear was simulated using 400,000 cycles in a Leinfelder-Suzuki (Alabama) device with a stainless-steel ball bearing antagonist. Volume loss and maximum depth of wear facets were measured using a Proscan 2100 noncontact profilometer in conjunction with analyzing software. Scanning electron microscopy observations were also conducted on the wear specimens. Results: Simulated occlusal wear was significantly different (P< 0.05) among the materials tested. FF, GB and GF showed significantly less wear than the other tested resin composites. The rank order of volume loss and maximum depth was GF-GB-FF-FB-CM-HF-TB-SD. (Am J Dent 2020;33:74-78).

 

 

 

 

 

Mail: Dr. Akimasa Tsujimoto, 1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan. E-mail: tsujimoto.akimasa@nihon-u.ac.jp

 

 

 

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                                                                                                                                     Research Article

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Efficacy of laser application in dental bleaching: A randomized clinical controlled trial

 

Julieta M. Méndez Romero, dds,  Ulises A. Villasanti Torales, dds, msc   &   Carlos J. Villalba Martinez, msc

 

Abstract: Purpose: To evaluate the bleaching efficacy of laser application with chemical treatment compared to chemical treatment alone. Methods: This was a randomized controlled trial (RCT), single blind (evaluator), in 24 patients randomized into two groups: Laser and chemical intervention (12) or chemical intervention alone without laser (12). The commercial products used were Whiteness HP 35% hydrogen peroxide gel and the Whitening Laser II of DCM equipment. The color was measured with a spectrophotometer before, immediately and 3 days after the bleaching procedure. The trial outcome measures were obtained using the Vita EasyShade spectrophotometer and the International CIELCh system. To establish differences before vs. after treatments and between groups, the T test and chi² tests were applied. The data was statistically analyzed with Student’s T-test (P ≤ 0.05). Results: After applying the delta formula to measure the change in color, both groups gave clinically significant results before vs. after bleaching procedures (P≤ 0.05). The deltas for luminosity, chroma, and hue all showed significant improvements for baseline to 15 minutes post treatment (P≤ 0.05), baseline to 3 days post treatment (P≤ 0.05), but not for 15 minutes to 3 days post treatment (P≥ 0.05). When comparing between groups applying T-test, no statistically significant differences were found (P≥ 0.05) for all three deltas. When comparing sensitivity after bleaching, no differences were found between groups (P≥ 0.05). (Am J Dent 2020;33:79-82).

 

 

 

 

Mail: Dr. Julieta Méndez, Gral. Diaz St. between Yrendague and Sargento Primero Benitez, Coronel Oviedo, Caaguazu, Paraguay.  E-mail: julieta_mendez92@hotmail.com

 

 

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                                                                                                                                       Research Article

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Effects of cigarette smoke on color, roughness and gloss of high-viscosity

bulk-fill resin composites

 

Jéssica Dias Theobaldo, dds, ms, Waldemir Francisco Vieira Junior, dds, msc, phd, Karine Laura Cortellazzi, dds, ms, phd, Giselle Maria Marchi, dds, ms, phd, Débora Alves Nunes Leite Lima, dds, ms, phd  &  Flávio H.B. Aguiar, dds, ms, phd

 

Abstract: Purpose: To evaluate the effect of cigarette smoke (CS) on color, roughness and gloss of bulk-fill resin composites. Methods: Resin discs (10 × 2 mm) were made for resin composites (n= 10): Filtek Z250XT (control), Filtek One Bulk Fill (FOBF), Tetric N-Ceram Bulk-Fill (TBF) and Aura Bulk-Fill (ABF). The color (ΔL*, Δa*, Δb*, ΔE and ΔE00), roughness (Ra) and gloss analyses were performed at the baseline and after CS exposure (10 packs of cigarettes - Marlboro Red). The data were analyzed with repeated measures ANOVA and Tukey test for Ra and gloss; and one-way ANOVA and Tukey’s test for ∆L*, ∆a*, ∆b*, ∆E and ∆E00 (α= 0.05). Results: For ∆L*, all groups presented reduced luminosity and all bulk-fill resin composites differed statistically from the control (P< 0.05). ABF presented greater variation of ∆L*, differing statistically from all resin composites (P< 0.05). For ∆E and ∆E00, all bulk-fill resin composites showed greater staining, differing statistically from the control, which presented lower values. For Ra, after CS, only ABF presented a decrease, differing statistically from baseline (P< 0.05). After CS smoke, all groups presented gloss increase, statistically different from the baseline (P< 0.05); and when compared among resin composites, no difference was found. (Am J Dent 2020;33:83-88).

 

 

Mail: Dr. Flávio H.B. Aguiar, Department of Restorative Dentistry, Piracicaba Dental School, University of Campinas, Av. Limeira, 901, Piracicaba, SP, 13.414-903,  Brazil.   E-mail: aguiar@fop.unicamp.br

 

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Hydrogen peroxide degradation of bleaching systems with different trays: Randomized clinical trial

 

Mariane Cintra Mailart, dds, msc, Carolina de Siqueira Ferracioli, Carlos Rocha Gomes Torres, dds, phd, Renato Miotto Palo, dds, msc, phd  &  Alessandra Bühler Borges, dds, msc, phd

 

Abstract: Purpose: This crossover study evaluated the hydrogen (HP) and carbamide (CP) peroxide degradation of bleaching gels in prefilled (PT) and customized trays (CT). Methods: Volunteers were randomly allocated to treatments (n=10): PT-HP/OGO (Opalescence GO-10%); CT-HP/WTC (White Class-10%) or CT-CP/OPF (Opalescence PF-10%). Gel samples were collected from the upper and lower trays in each period (baseline, 15, 30, 50 and 120 minutes). HP concentration was determined with the potassium permanganate titration method. Degradation was calculated based on initial concentration of gels. Repeated measures two-way ANOVA and Tukey’s test (5%) were applied. Results: Bleaching gels exhibited exponential degradation over time. In 30 minutes, no significant differences in degradation among them were detected (P= 0.13). After 2 hours, lower degradation of CT-CP/OPF (61.85±10.65), compared with hydrogen peroxide in PT and CT (71.55±8.24 and 78.69±9.33, respectively) was observed. The gels showed higher degradation rate in lower trays than in upper trays in all evaluated times. In general, the bleaching gels in lower trays degraded more than in upper trays. The carbamide peroxide gel presented lower degradation than hydrogen peroxide after 2 hours. The degradation of the 10% hydrogen peroxide gel used in prefilled trays was higher than the one in customized trays after 30 minutes, but after 120 minutes, the degradation rate was similar for both. (Am J Dent 2020;33:89-94)

 

 

 

 

Mail: Dr. Alessandra Bühler Borges, Av. Engenheiro Francisco José Longo, 777, Jardim São Dimas, São José dos Campos, SP, 12245-000 Brazil.  E-mail: alessandra.buhler@unesp.br

 

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Efficacy and safety of naproxen sodium 440 mg versus acetaminophen 600

mg/codeine phosphate 60 mg in the treatment of postoperative dental pain

 

Eishdeep Cattry, pharmd,  Emanuel Troullos, dmd  &  Alberto Paredes-Diaz, md

 

Abstract: Purpose: Two studies evaluated the efficacy and safety of a single dose of naproxen sodium 440 mg (NS) compared to the combination of acetaminophen 600 mg and codeine phosphate 60 mg (AC) in subjects with postoperative dental pain. Methods: The two studies were single center, randomized, double-blind and double-dummy trials. In both studies, subjects were randomized into one of the following three treatments in a 2:2:1 ratio, respectively: NS, AC, or placebo (PBO). Subjects were administered study medication when they had at least moderate pain following the surgical removal of three or four impacted molars, at least one of which was a mandibular partial or complete bony impaction. Efficacy assessments were completed over an 8-hour evaluation period. The co-primary efficacy assessments in both studies were time-weighted sum of categorical pain intensity differences over 4 hours (SPID4) and time-weighted sum of pain relief scores over 4 hours (TOTPAR4). Other efficacy assessments such as summed scores over 8 hours, time to onset of relief, time to rescue medication and global rating of medication were also assessed. Results: In Study 1, there were 225 subjects evaluated for efficacy, and 228 evaluated for safety. In Study 2, there were 230 subjects evaluated for efficacy and safety. In both studies, NS and AC were significantly better than placebo for almost all efficacy measures. In Study 1, NS was significantly superior to AC for all summed efficacy scores over 4 and 8 hours except for SPID4. NS was also superior to AC for most individual time point scores from 3 through 8 hours, as well as for the time to taking rescue medication. Both actives had a similar onset of effect. The incidence of adverse events (AEs) was significantly higher in the AC group compared to NS and PBO. The most frequently reported AEs with AC were gastrointestinal (GI) and nervous system events. In Study 2, there were no statistically significant differences between the two active treatments for any summed efficacy score, except for TOTPAR8, where NS was significantly better than AC. NS was significantly better than AC for individual pain relief time point scores from 3 through 8 hours and significantly better for individual pain intensity difference scores from 5 through 8 hours. AC had a significantly faster onset of effect compared to NS, but NS had a significantly longer time to rescue compared to AC. Nervous system AEs (dizziness and somnolence) were reported significantly more frequently with AC compared to NS. In conclusion, Both NS and AC are effective in the relief of postoperative dental pain. NS provided comparable to superior relief vs. AC and its analgesic effects lasted significantly longer. NS was well tolerated and resulted in a lower rate of AEs than AC. (Am J Dent 2020;33:106-112).

 

 

 

 

 

Mail: Dr. Eishdeep Cattry, Bayer Healthcare LLC, 100 Bayer Blvd., Whippany, NJ 07981, USA. E-mail: eishdeep.cattry.ext@bayer.com

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                                                                                                                       Systematic Review Article

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Stabilized stannous fluoride dentifrice in relation to dental caries, dental erosion and dentin hypersensitivity: A systematic review

 

Katarina Konradsson, rdh, phd,  Peter Lingström, dds, phd,  Claes-Göran Emilson, dds, phd, Gunnar Johannsen, dds, phd,  Per Ramberg, dds, phd  &  Annsofi Johannsen,  rdh, phd

 

Abstract: Purpose: To review the scientific evidence for the efficacy of stabilized stannous fluoride (SnF₂) dentifrice in relation to dental caries, dental erosion and dentin hypersensitivity. Methods: Medline OVID, Embase.com, and the Cochrane Library were searched until January 2018. Two researchers independently selected studies according to inclusion and exclusion criteria, data were extracted, the risk of bias in eligible studies was assessed and a meta-analysis was performed wherever feasible. Results: Three studies on dental caries, eight studies on dental erosion and 11 on dentin hypersensitivity were included. Risk of bias was judged as high for most of the caries and erosion studies and low or medium for the hypersensitivity studies. A similar or slightly higher anti-caries activity compared with non-stannous fluoride dentifrices was observed. Stannous fluoride showed a greater anti-erosive potential in seven of the eight studies. A mean difference score in favor of stannous fluoride dentifrices compared with controls was found in a meta-analysis including six 8-week hypersensitivity studies. (Am J Dent 2020;33:95-105).

 

 

 

Mail: Dr. Katarina A. Konradsson, Department of Odontology, Faculty of Medicine, Umeå University, SE-901 87 Umeå, Sweden. E-mail: katarina.a.konradsson@umu.se