Research Article

Wear of an ion-releasing powder/liquid polymer resin in relation to that of glass-ionomer and conventional resin composites

 

Siegward Dietmar Heintze, dmd, phd, Gabriele  Zellweger  &  Arnd Peschke, dmd

 

Abstract: Purpose: To evaluate the wear in vitro of a new ion-releasing powder/liquid polymer resin in relation to that of glass-ionomer derivatives and conventional composites. Methods: Flat specimens (eight per material) of the ion-releasing powder/liquid polymer resin Cention N, five resin-modified glass-ionomer cements [ChemFil Rock, Equia Fil (with and without coating), Fuji II, Photac Fil, Riva], six conventional glass-ionomer cements (Fuji IX, Fuji IX GP, Ionofil Molar, Ketac Fil Plus, Ketac Molar, Ketac Universal), and two popular conventional resin composites (CeramX, Filtek Z350 XT) were processed and luted to aluminum holders. After storage in water at 37°C for 24 hours, the specimens were polished to 2,500 grit and subjected to the Ivoclar wear method, which mainly simulates attrition wear using a commercially available chewing simulator. A standardized stylus made of pressable ceramic (IPS Empress) hits flat specimens 120,000 times with a 5 kg weight and a lateral movement of 0.7 mm under constant exchange of water at different temperatures (5°C/55°C). The vertical loss was measured on plaster replicas with a laser scanner and 3D software. The Ivoclar wear method moderately correlates with clinical wear. Results: The mean vertical wear of the resin-modified glass-ionomer cements was statistically significantly higher, between 616±44 µm (Ionofil Molar) and 946±101 µm (Fuji IX GP) than that of the ion-releasing polymer resin Cention N (327±63 µm) (ANOVA post-hoc Tukey B, P< 0.01), which was in the same statistical group of the conventional resin CeramX (323±31 µm). Filtek Z350 XT showed significantly lower wear (221±19 µm) (ANOVA post-hoc Tukey B, P< 0.05). The materials ChemFil Rock (39±13 µm), Photac Fil (41±9 µm), and Fuji II (42±8 µm) had the lowest antagonist wear, while Ketac Fil Universal (143±37 µm) and CeramX (135±13 µm) had the highest antagonist wear. Antagonist wear for Cention N was somewhere in between (90±21 µm). (Am J Dent 2020;33:171-177).

 

 

 

 

 

Mail: Dr. Siegward D. Heintze, Ivoclar Vivadent AG, Bendererstrasse 2, FL-9494 Schaan, Liechtenstein.
E-mail:  siegward.heintze@ivoclarvivadent.com

 

 

                                                                                                                                             Research Article

Resin cement removal from titanium dental implant surface using a novel side-firing laser fiber and Er,Cr:YSGG irradiation

 

Christopher J. Walinski, dds  &  Keng-Liang Ou, ms, phd

 

Abstract: Purpose: To evaluate the influence of an erbium, chromium: yttrium, scandium, gallium, garnet (Er,Cr:YSGG) laser using multiple tip types, on the removal of retained cement on a titanium implant surface. Methods: Nine titanium dental implants were coated with a non-eugenol resin composite implant cement. An Er,Cr:YSGG device at a wavelength of 2,780 nm was fitted sequentially with three laser fiber tips: (1) 6 mm long, 600 µm diameter end-firing, quartz; (2) 9 mm long, Radial-Firing Perio Tip, 500 µm diameter, quartz; and (3) 18 mm long Side-Firing Tip, 800 µm × 300 µm, sapphire. Irradiation on the implant surfaces was performed in short pulse mode (140 µsec pulse duration) with output power of 1.5 W, 50% water, 40% air, and either: (1) 15 Hz, 100 mJ/pulse; (2) 30 Hz, 50 mJ/pulse; or (3) 40 Hz, 37.5 mJ/pulse. Three trials each were completed for each of three different fiber tip types for a total of 27 trials (three trials for each of the nine groups). Results: All samples in Groups 1-6 demonstrated complete removal of cement from the implant surface. SEM inspection revealed a high degree of melting of the resin composite cement on the implant surface in all samples treated with 100 mJ/pulse (Groups 1, 2, 3). At 50 mJ/pulse (30 Hz), the results of the end-firing and side-firing tips improved remarkably, with clean implant surfaces and comparatively little melting. The side-firing fiber at 50 mJ/pulse and 30 Hz provided the best overall combination of cement removal and least amount of residual melted material on the implant surface. Based on the limitations of this study, the most appropriate method of removing residual cement from a TiUnite coated titanium implant surface is by using an Er,Cr:YSGG laser device fitted with a side-firing laser tip. Laser parameters of 50 mJ/pulse and 30 Hz (1.5W average power), with at least 50% water and 40% air in the aerosolized water spray are ideal. (Am J Dent 2020;33:178-182).

 

 

Mail: Dr. Christopher J. Walinski, Touro College of Dental Medicine, New York Medical College, 19 Skyline Drive, Hawthorne, NY 10532, USA. E-mail: christopher.walinski@touro.edu

 

 

                                                                                                                                             Research Article

 

Effects of toothpaste containing surface pre-reacted glass-ionomer (S-PRG) filler on crystallinity and acid resistance of hydroxyapatite

 

Toshiyuki Suge, dds, phd  &  Takashi Matsuo, dds, phd

 

Abstract: Purpose: To examine the acid resistance of experimental toothpaste containing different wt% of surface pre-reacted glass-ionomer (S-PRG) filler. Methods: Hydroxyapatite (HAP) pellets were treated with toothpaste containing 0, 1, 5, 10, 20, or 30 wt% S-PRG filler for 5 minutes. A demineralization and remineralization cycle were repeated for 7 days. The demineralized depths of the pellets were measured using a surface roughness analyzer. The crystallinity of both HAP and dicalcium phosphate dehydrate (DCPD) after the S-PRG treatment was measured by a powder X-ray diffraction (XRD) analysis. Fluoride gel (9,000 ppmF) was used for comparison. Results: The demineralizd depth decreased with increases in the S-PRG filler concentration. The demineralized depth with the 30 wt% S-PRG treatment (4.6 µm ± 2.0) was slightly greater than that with the fluoride gel (3.3 µm ± 0.5), but not significantly different (P< 0.05). However, significant differences were observed in demineralized depths between the fluoride gel and the other wt% of S-PRG tested (P< 0.05). In the XRD analysis, no crystallinity changes were noted in HAP or DCPD after the S-PRG or fluoride gel treatments. The formation of calcium fluoride was not detected in any treatment group. (Am J Dent 2020;33:183-186).

 

 

Mail: Dr. Toshiyuki Suge, Department of Conservative Dentistry, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15 Kuramoto, Tokushima 770-8504, Japan.  E-mail: suge@tokushima-u.ac.jp

 

                                                                                                                                            Research Article

Effect of a continuous mechanical polishing protocol and toothbrushing on the surface roughness of acrylic resin teeth

 

Giovanna Guerreiro Guimarães, dds,  Marina Fiuza Sarte, dds,  Joel Oliveira Barreto, dds, msc,

Karina Matthes de Freitas-Pontes, dds, msc, phd  &  Romulo Rocha Regis, dds, msc, phd

 

Abstract: Purpose: To evaluate in vitro the effect of a continuous mechanical polishing protocol, performed in different periods, on the surface roughness of acrylic resin teeth subjected to toothbrushing (Br). Methods: Artificial acrylic teeth (n=30) were randomly divided into three groups according to the polishing protocol and toothbrushing (Br): Br; Br+Pol15 (Br associated with a biweekly polishing); Br+Pol30 (monthly polishing). Br group was subjected to a total of 89,000 brushing cycles. Polishing was performed by applying aluminum oxide paste to the specimens with a felt wheel coupled to an electric motor (5 seconds, 3,000 rpm) after each 741 and 1482 brushing cycles for Br+Pol15 and Br+Pol30 groups, respectively. A contact profilometer and an analytical balance were used to measure surface roughness and mass changes before (T0) and after 1, 2, 3, and 5 years (T4) of simulated toothbrushing. Scanning electron microscopy (SEM) images were obtained. Differences among groups were tested by means of two-way ANOVA/Bonferroni tests (P= 0.05). Results: Toothbrushing gradually increased surface roughness [T0 – 0.16 (0.01); T4 - 0.30 (0.10); P< 0.001]. The tested polishing promoted a significant roughness reduction (P< 0.001) for both biweekly [T4 - 0.09 (0.01)] and monthly [T4 - 0.13 (0.02)] regimes, and it did not influence the mass alterations caused by toothbrushing. SEM showed a smoother aspect of the material surface subjected to biweekly polishing with less defects caused by brushing abrasiveness. (Am J Dent 2020;33:187-190).

 

 

 

 

 

 

 

 

Mail: Dr. Romulo Rocha Regis, Department of Restorative Dentistry, Federal University of Ceará, Alexandre Baraúna St. 949, Rodolfo Teófilo, Fortaleza, CE, 60430-160, Brazil.  E-mail: romuloregis@hotmail.com

 

 

                                                                                                                                           Research Article

Effect of saliva and beverages on the surface roughness and hardness of acrylic resin modified with nanomaterial

 

Mirian Maiumi Muraishi Kamimura, dds,  Denise Tornavoi de Castro, phd, Mariana Lima da Costa Valente, phd  &  Andréa Cândido dos Reis, phd

 

Abstract: Purpose: To evaluate the surface roughness and hardness of thermopolymerized acrylic resin incorporated with nanostructured silver vanadate (AgVO₃) subjected to saliva and beverages. Methods: The 128 specimens (5×5×2 mm) were prepared in thermopolymerized acrylic resin, according to the AgVO₃ concentrations (n=32): 0%, 2.5%, 5% and 10%. The roughness and hardness were analyzed before and after immersion in saliva, Coca-Cola, orange juice and red wine, for 12 and 24 days. 2-way ANOVA and Bonferroni test (α= 0.05) were performed. Results: After 12 days, Coca-Cola caused the highest roughness increase in the 2.5% group). The 10% group with saliva presented a higher roughness increase (P= 0.009). The control presented a decrease in roughness when in beverages (P< 0.05). After 24 days, orange juice and Coca-Cola produced a higher decrease in roughness in the control group (P< 0.05). After 12 days, saliva and wine produced a higher decrease in hardness of the 2.5% group (P< 0.05). Coca-Cola produced a decrease in hardness and wine an increase in hardness in the group with 10% AgVO₃ concentration (P< 0.05). After 24 days, the group with 2.5% presented the highest decrease in hardness (P< 0.05). The immersions produced decreased hardness in the acrylic resin. Initially, there was an increase in roughness, however, over time, it decreased. (Am J Dent 2020;33:191-195).

 

 

 

 

 

 

 

 

 

 

 

Mail: Dr. Andréa Cândido dos Reis, Av. do Café, s/nº - Ribeirao Preto - SP 14040-904, Brazil.  E-mail: andreare73@yahoo.com.br

 

 

                                                                                                                                             Research Article

The effect of silver diamine fluoride and cleaning methods on bond strength

of glass-ionomer cements to caries-affected dentin

 

Paulo Vitor Fernandes Braz, dds, ms,  Andressa Fabro Luciano dos Santos, dds, ms, phd, Soraya Coelho Leal, dds, ms, phd,  Patrícia Nóbrega Rodrigues Pereira, dds, phd &  Ana Paula Dias Ribeiro, dds, ms, phd

 

Abstract: Purpose: To evaluate the effect of silver diamine fluoride (SDF) application on the microshear bond strength (MBS) of glass-ionomer cements (GIC) to caries-affected dentin (Part 1) and dentin cleaning methods to reduce SDF’s potential effect on MBS (Part 2). Methods: For Part 1, 56 extracted human teeth were randomly divided into eight groups with GIC, 38% SDF application and dentin substrate. Samples of artificial caries-affected human dentin were treated or not with 38% SDF and restored with conventional or resin-modified GIC. The same procedures were performed in sound dentin tested for MBS test after 24 hours. In Part 2, different dentin cleaning agents (water, aluminum oxide, and pumice slurry) were tested after SDF application. The procedure was performed on the group that presented the worst values for MBS in Part 1. Fracture mode was evaluated under scanning electron microscope. Data were statistically analyzed by ANOVA. Results: MBS was affected by the presence of caries and the type of material, with the conventional GIC the most affected (P< 0.05). Pumice slurry was superior in comparison to the other agents in cleaning SDF-treated dentin. Fracture evaluation showed more mixed failures in all the groups. (Am J Dent 2020;33:196-200).

 

 

Mail: Dr. Ana Paula Dias Ribeiro, Department of Restorative Dental Sciences, College of Dentistry, University of Florida, Gainesville, FL 32610, USA.  E-mail: aribeiro@dental.ufl.edu

 

                                                                                                                                           Research Article

Effect of biofilm exposure on marginal integrity of composite restorations

 

Amanda Mahammad Mushashe, dds, msc, Sarah Aquino de Almeida, dds, msc, Jack Libório Ferracane, msc, phd, Justin Merritt, msc, phd  &  Gisele Maria Correr, dds, msc, phd

 

Abstract: Purpose: To evaluate the effect of bacterial exposure on the marginal integrity of dentin-resin interfaces for composites with and without bioactive glass (BAG). Methods: Cavity preparations of 5 mm width and 1.5 mm depth were machined into dentin disks by means of a computer controlled milling system. After applying the bonding agent, cavity preparations (n=3-5) were restored by incremental technique with experimental resin composites (50:50 BisGMA/TEGDMA: 72wt% filler) with different filler compositions: control – 67 wt% silanated strontium glass and 5wt% aerosol-silica filler and BAG – 57 wt% silanated strontium glass and 15 wt% BAG-65 wt% silica. Samples were then stored in sterile Todd-Hewitt media or co-incubated with Streptococcus mutans (UA 159), at 37°C, 5% CO₂ for 1-2 weeks. For samples co-incubated with a living biofilm, a luciferase assay was performed in order to assess its viability. Surfaces were impressed before and after each storage condition and replicas examined in a scanning electron microscope. Using image analysis software (Image J), the discontinuous margins percentage (%DM) was quantitatively assessed. Data were analyzed using two-way ANOVA followed by Tukey’s test (α= 0.05). Results: Gap size ranged between 7-23 µm. The bacterial exposure significantly increased the %DM in both groups predominantly due to the formation of new gap regions. There was no difference between control and BAG composites regarding %DM and the biofilm viability. Bacterial exposure promoted degradation of composite restoration marginal integrity, with no difference between composites with and without BAG. (Am J Dent 2020;33:201-205).

 

 

 

 

 

 

Mail: Dr. Gisele Maria Correr, School of Health Sciences, Graduate Program in Dentistry, Universidade Positivo. Rua Professor Pedro Viriato Parigot de Souza 5300, Campo Comprido, Curitiba – PR 81280-330 Brazil. E-mail: gmcnolasco@gmail.com

 

                                                                                                                                           Research Article

Dentin moisture does not influence postoperative sensitivity in posterior

restorations: A double-blind randomized clinical trial

 

Andrea dos Santos de Castro, dds, msc,  Bianca Medeiros Maran, dds, msc, phd, Mario Felipe Gutiérrez, dds, msc, phd,  Eveline Claudia Martini, dds, msc, Fabiana Dias Simas Dreweck, dds, msc,  Luján Mendez-Bauer, dds, msc, phd,  Alessandra Reis, dds, phd &  Alessandro Dourado Loguercio, dds, msc, phd

 

Abstract: Purpose: This double-blind, randomized clinical trial evaluated the influence of dentin moisture on postoperative sensitivity (POS) in posterior restorations using a simplified etch-and-rinse adhesive, until 12 months of clinical service. Methods: 90 restorations were inserted in 45 patients to treat carious lesions or to replace existing posterior restorations with a depth ≥ 3 mm. After cavity preparation, the simplified etch-and-rinse adhesive (Adper Single Bond 2) was applied on dry or wet dentin followed by a bulk-fill resin composite (Filtek Bulk Fill) under rubber dam isolation. The patient’s spontaneous and stimulated POS was evaluated at baseline and after 7 days, 6 months, and 12 months of clinical evaluation. The secondary parameters (marginal discoloration, marginal adaptation, fracture and recurrence of caries) were evaluated by World Dental Federation (FDI) criteria after 7 days, 6 and 12 months of clinical evaluation. Results: No significant spontaneous and stimulated POS was observed when dry and wet dentin were compared (P> 0.05). A significant and higher risk of spontaneous POS (18.6%; 95% CI 9.7 to 32.6) occurred up to 48 hours after restoration placement for both groups when compared to all evaluation times (P< 0.03). However, the intensity of POS was mild at up to 48 hours with a difference between the dry and wet dentin groups (P> 0.79). When secondary parameters were evaluated, no significant difference between the groups were observed (P> 0.05). (Am J Dent 2020;33:206-212).

 

 

 

 

Mail: Prof. Dr. Alessandro D. Loguercio, Rua Carlos Cavalcanti, 4748 Bloco M, Sala 64-A, Uvaranas, Ponta Grossa, Paraná 84030-900, Brazil. E-*: aloguercio@hotmail.com

 

 

                                                                                                                                         Research Article

Clinical and radiographic evaluation of high viscosity bulk-fill resin composite restorations

 

Luiza Salles Alves Berti, dds, ms,  Cecilia Pedroso Turssi, dds, ms, phd, Flávia Lucisano Botelho do Amaral, dds, ms, phd,  Roberta Tarkany Basting, dds, ms, phd, José Luiz Cintra Junqueira, dds, ms, phd,  Francine Kuhl Panzarella, dds, ms, phd, André Figueiredo Reis, dds, ms, phd  &  Fabiana Mantovani Gomes França, dds, ms, phd

 

Abstract: Purpose: To perform a clinical and radiographic evaluation comparing Filtek Bulk Fill high viscosity bulk-fill resins with Filtek Z350 XT nanoparticulate for 1 year. Methods: 58 restorations were performed for each material (bulk-fill and nanoparticulate), for a total of 116 restorations. Among these, 42 Class I and 16 Class II restorations were performed for each group, in molars and premolars. Clinical evaluation was performed 7 days (baseline), 6 months and 1 year after restorations, using the World Dental Federation (FDI) criteria. Radiographs were obtained at 7 days and 1 year after the restoration was placed and the radiopacity was measured using Image J software at the same time interval. Results: Of the 70 restorations available for evaluation at 1 year, the Mann-Whitney and Friedman tests showed no statistically significant difference for the FDI criteria analyzed. Greater radiopacity was observed for bulk-fill resin compared to nanoparticulate (two-way ANOVA, P= 0.022). This same test showed no difference in radiopacity between the groups in the two evaluation periods (P= 0.062). The high viscosity bulk-fill resin composite presented similar clinical performance to nanoparticulate resin in this evaluation period and higher radiopacity was observed for this material when compared to nanoparticulate resin, in both time periods. (Am J Dent 2020;33:213-217).

 

 

Mail: Profa. Dra. Fabiana Mantovani Gomes França, Faculty São Leopoldo Mandic, Research Institute São Leopoldo Mandic, Rua José Rocha Junqueira, 13 Swift, Campinas - SP CEP 13045-755, Brazil.  E-mail: biagomes@yahoo.com

 

 

                                                                                                                                      Research Article

The relative clinical efficacy of three 0.454% stannous fluoride dentifrices for the treatment of gingivitis over 3 months

 

Tao He, dds, phd,  Sushma Nachnani, phd,  Steve Lee, dds,  Yuanshu Zou, phd,  Julie Grender, phd, Svetlana Farrell, dds, phd,  Paul Sagel, bsche   &  Aaron R. Biesbrock, dmd, phd, ms

 

Abstract: Purpose: To assess the safety and efficacy of three stannous fluoride (SnF₂) dentifrices in the reduction of gingivitis versus a negative control dentifrice. Methods: This was a randomized, controlled, double-blind, four-treatment parallel group study. 120 healthy adult volunteers with established gingivitis were enrolled and randomly assigned to one of four dentifrice treatment groups (30/group): 0.454% SnF₂ + citrate dentifrice A; 0.454% SnF₂ + sodium hexameta-phosphate dentifrice B; 0.454% SnF₂ + pyrophosphate dentifrice C; or 0.76% sodium monofluorophosphate negative control group. Subjects brushed with their assigned dentifrice and an assigned regular manual toothbrush (Oral-B Indicator) for 1 minute twice daily for 12 weeks. Number of gingival bleeding sites and Löe-Silness Gingival Index (LSGI) scores were assessed at baseline and at Weeks 2, 4 and 12. Results: 120 subjects were enrolled and 112 completed the trial. Subjects had an average age (SD) of 39.31 (14.5) years; 67% of subjects were female. Overall baseline means (SD) were 81.2 (25.6) for number of bleeding sites and 1.51 (0.197) for mean LSGI score. Baseline disease levels were balanced across all treatment groups. At Week 2, SnF₂ dentifrices A and B demonstrated a significant reduction in gingival bleeding sites versus the negative control; however, SnF₂ dentifrice C was not significantly different from the negative control (P= 0.15). At Weeks 4 and 12, all SnF₂ dentifrices demonstrated a significant gingival bleeding site reduction versus the negative control (P< 0.001). At Weeks 2, 4 and 12, the SnF₂ dentifrices were rank ordered dentifrice A > dentifrice B > dentifrice C for reduction in gingival bleeding sites (P< 0.001). The same trends were seen for LSGI scores. (Am J Dent 2020;33:218-224).

 

 

 

 

 

 

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