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Aim. Several new bioactive compounds were recently introduced to the market with favorable ion release, tooth remineralization, and alkalizing potential. This study sought to compare the phosphate ion release and alkalizing potential of three bioactive materials in comparison with composite resin. Methods. Thirty-six discs (2 × 6 mm) were fabricated from Fuji II LC resin modified glass ionomer (RMGI), Activa BioActive, Cention N, and Z250 composite in plastic molds. The specimens were stored in distilled water for 24 and 48 h and 6 months. Half of the specimens were used to assess the phosphate ion release while the other half were used to assess the alkalizing potential 1 h after pH drop from 6.8 to 4. Phosphate ion release was quantified by a spectrophotometer while the pH value was measured by a pH meter. Data were analyzed using two-way ANOVA, one-way ANOVA, and Tukey’s HSD test (for pairwise comparisons) at 0.05 level of significance. Results. At 24 h, the maximum phosphate ion release in distilled water occurred in the Fuji II LC group followed by Cention N, Activa BioActive, and Z250. At 6 months, Cention N followed by Activa BioActive showed higher phosphate ion release than Fuji II LC and Z250. No significant difference was noted between Activa BioActive and Cention N at any time point. All materials, except for Z250, increased the pH of the environment. Fuji II LC had maximum alkalizing effect at all time points followed by Cention N and Activa BioActive. Conclusion. Use of bioactive compounds is a promising method to ensure phosphate ion release, and can have a positive effect on tooth remineralization over time. Also, bioactive compounds can alkalize an acidic environment.

Background Successful endodontic therapy requires prevention of bacterial leakage between the root canal filing and root-canal walls. Sealing quality of a root canal filling depends strongly on the sealing ability of the sealer used. The present study aimed to evaluate the bacterial leakage resistance of AH Plus sealer modified with silver nanoparticles. Methods Forty sound teeth were obturated using lateral compaction technique except for five teeth as the negative controls. After considering five teeth as the positive controls (filled without sealer), the remaining teeth were assigned to two groups (n = 15) in terms of the sealer used (AH Plus sealer and silver nanoparticle-modified AH Plus). Bacterial leakage was evaluated in saliva using the two-chamber technique in every 24 h. When all the samples in the test groups were contaminated, the study was terminated. The data were analyzed with log-rank statistical test. Results All samples in both experimental groups were contaminated during the 3-months period of observation. There was no significant difference in contamination time between study groups ( P  > 0.05). Conclusions Silver nanoparticles used in tested concentration did not improve the bacterial leakage resistance of AH Plus sealer.

Objectives: Bonding of orthodontic attachments to enamel is essential in orthodontic treatment. This study aimed to assess the shear bond strength (SBS) of orthodontic eyelets to the enamel surface using a moisture-resistant self-adhesive resin cement under isolation in comparison with saliva and blood contamination. Materials and Methods: This in vitro experimental study used 78 sound human premolars extracted for orthodontic purposes. Brackets were bonded to the teeth with either Transbond XT or Embrace WetBond in isolated conditions and also in presence of blood and saliva contamination. The samples were subjected to thermocycling, and then the SBS of the eyelets attached to the enamel was measured in each group. The adhesive remnant index (ARI) was also determined under a stereomicroscope. Data were analyzed by two-way ANOVA, Tukey’s test, and Kruskal-Wallis test (alpha=0.05). Results: The SBS of Transbond XT group was significantly higher than Embrace WetBond group under isolation and contamination with saliva and blood (P=0.000). In both adhesives, the SBS under isolated conditions was significantly higher than that in presence of blood and saliva contamination (P=0.000). There was a significant difference between the isolation and blood and saliva contamination groups regarding the ARI scores (P<0.05). Conclusion: Transbond XT adhesive yielded a stronger bond than WetBond Embrace in both situations; however, it appears that Embrace WetBond can also provide satisfactory results and minimize enamel damage during debonding.

Objectives: The present study was conducted to compare the flexural strength of a bioactive composite and a reinforced hybrid glass ionomer (GI). Materials and Methods: In this in vitro experimental study, 10 rectangular-shaped specimens were fabricated from Activa Bioactive composite (N=5) and EQUIA Forte Coat GI (N=5) using stainless steel molds with internal dimensions of 2×2×25mm according to the manufacturers’ instructions. The flexural strength of the specimens was measured with a universal testing machine with the three-point bending test using a load of 50±16N/min at a crosshead speed of 0.75±0.25mm/min. The data were analyzed using the Mann-Whitney U test (α=0.05). Results: The mean flexural strength was 57.91MPa for the bioactive composite and 19.20MPa for the reinforced hybrid GI. The mean flexural strength of the bioactive composite was significantly higher than that of hybrid GI (P=0.008). Conclusion: Within the limitations of this in vitro study, the results indicate that the Activa Bioactive composite exhibits greater flexural strength compared to EQUIA Forte Coat GI.

Background This study aimed to investigate the effect of root dentin pretreatment with different concentrations of chitosan on the push-out bond strength (PBS) of fiber post using a self-adhesive resin cement. Methods After post-space preparation in 56 maxillary central incisors that underwent endodontic treatment and were filled with gutta-percha (Spident, Korea) and AH Plus resin sealer (Dentsply, USA), the teeth were randomly divided into four groups ( n  = 14) for pretreatment with 2.5% chitosan, 1% chitosan, 17% ethylenediamine tetra-acetic acid (EDTA), and saline. Fiber posts were cemented into the root canals using Panavia SA resin cement. The teeth were then thermocycled (5°C-55°C, 5,000 cycles), and the roots were sectioned into coronal, middle, and apical thirds. The PBS was measured in a universal testing machine. The mode of failure was also determined under a stereomicroscope and a scanning electron microscope (SEM). The PBS data were analyzed using two-way ANOVA and Tukey’s post hoc test. Results The mean PBS of 2.5% chitosan group was significantly higher than that of control group at the coronal, middle, and apical thirds of the root in the post-placement region. However, 2.5% chitosan group had a significant difference in PBS with the EDTA group only in the middle and coronal thirds ( P  < 0.05). Pretreatment with 1% chitosan and 17% EDTA did not significantly increase the PBS at any level from the root in the post-placement region. Cohesive failure was dominant in 2.5% chitosan group, while mixed failure had the highest frequency in other groups. Conclusion Root dentin pretreatment with 2.5% chitosan improved the PBS of fiber post to root dentin by using a self-adhesive resin cement.

Background. Today, various methods are used to increase the bond strength of zirconia in layering ceramics. This study evaluated the effects of nonthermal argon plasma on zirconia shear bond strength to layering porcelain. Materials and Method. In this experimental study, 42 square blocks of zirconia were prepared and randomly divided into three groups (n = 14) according to the applying surface treatment: (1) the control group (without any surface treatment), (2) the plasma-treated group with argon nonthermal plasma, and (3) the air abrasion group with 50 µm Al2O3 particles. All samples were layered with porcelain. One sample from each group was evaluated by electron microscopy (SEM) to examine the cross-sectional area of the zirconia–ceramic bond. The rest of the specimens were subjected to thermocycling with 5,000 baths to imitate the aging process in the mouth and then were tested for shear bond strength. The failure pattern of the samples was examined by stereomicroscope. Bond strength data were analyzed by one-way ANOVA test in three groups and Tamhane post hoc test in pairs. The significance level of p-value was considered 0.05. Results. The shear bond strength of the plasma-treated group was significantly higher than the control group (p=0.032) but the shear bond strength between the sandblast and the plasma-treated group was not significantly different (p=0.656). The shear bond strength between the sandblast and the control group was also not significant (p=0.202). Regarding the mode of failure, failures were mostly adhesive and then mixed. Examination of the samples under SEM showed that the bond area is the thickest in the sandblast group and also the surface roughness is the highest in the sandblast group and the lowest in the control group. Conclusion. This study demonstrated that the use of nonthermal argon plasma treatment is an effective way to enhance the quality and quantity of shear bond strength between layering porcelain and zirconia.

Objectives: Surface roughness is one of the important properties of composite restorations. Different polishing systems are used to provide an appropriate composite restoration surface. The aim of this study was to evaluate the effects of Sof-Lex, Eve, and Astropol polishing systems on composite resin surface roughness after aging. Materials and Methods: In this in vitro study, 36 composite discs (8×2mm) were fabricated. The specimens were randomly divided into three groups (N=12) for polishing with (I) Sof-Lex (3M ESPE), (II) Eve (Ernst Vetter GmbH), and (III) Astropol (Ivoclar/Vivadent) polishing systems. The specimens were then subjected to thermocycling. Surface roughness of the specimens was measured before and after polishing, and after thermocycling by a contact profilometer. Repeated Measures ANOVA was used to analyze the data (α=0.05). Results: Although Astropol showed slightly higher surface roughness in comparison to Sof-Lex and Eve, the level of surface roughness before and after polishing and after aging was not significantly different among the three polishing systems (P=0.704). Conclusion: Within the limitations of this in vitro study, Sof-Lex, Eve, and Astropol showed similar acceptable results with regard to composite resin surface roughness.

Objectives: This study aimed to evaluate the shear bond strength of ceramic brackets bonded to the enamel surface using Vertise Flow, with or without the application of phosphoric acid. Materials and Methods: Forty-five extracted human premolar teeth were randomly assigned to three groups (N=15) based on the adhesive used for bonding: 1) Transbond XT, etch, and bond; 2) Vertise Flow; 3) Etch and Vertise Flow. After a 500-round thermocycling procedure, the shear bond strength was measured using a universal testing machine. The samples were then evaluated under a stereomicroscope to determine failure modes, and the Adhesive Remnant Index (ARI) was measured for each group. The data were analyzed with one-way ANOVA and post-hoc Tamhane at a significance level of P<0.05. Results: The highest shear bond strength values were observed in the Transbond XT (13.5±5.38MPa), acid etch and Vertise Flow (11.2±2.89MPa), and Vertise Flow (6.2±3.16MPa) groups, respectively, in descending order. The Vertise Flow group exhibited a significantly lower shear bond strength value compared to the other two groups, with no significant difference between the latter two. Conclusion: While all three study groups demonstrated clinically acceptable shear bond strength values, Vertise Flow showed lower values compared to the other two adhesives. The Vertise Flow composite resin system, whether used alone or with acid etching, remains a suitable choice for bonding ceramic brackets, offering the advantage of a simplified bonding procedure.

Aim. This study aimed to assess shear bond strength (SBS) of resin cement to zirconia ceramic with different surface treatments by using Single Bond Universal. Methods. In this in vitro study, 50 zirconia discs (2 × 6 mm) were divided into 5 groups of (I) sandblasting with silica-coated alumina (CoJet)  + silane + Single Bond 2, (II) sandblasting with CoJet + Single Bond Universal, (III) sandblasting with alumina + Single Bond Universal, (IV) sandblasting with alumina + Z-Prime Plus, and (V) Single Bond Universal with no surface treatment. Resin cement was applied in plastic tubes (3 × 5 mm2), and after 10,000 thermal cycles, the SBS was measured by a universal testing machine. The mode of failure was determined under a stereomicroscope at × 40 magnification. Data were analyzed using one-way ANOVA. Results. The maximum (6.56 ± 4.29 MPa) and minimum (1.94 ± 1.96 MPa) SBS values were noted in groups III and I, respectively. Group III had the highest frequency of mixed failure (60%). Group V had the maximum frequency of adhesive failure (100%). Conclusion. Single Bond Universal + sandblasting with alumina or silica-coated alumina particles is an acceptable method to provide a strong SBS between resin cement and zirconia.

The management of teeth with deep caries, fracture, or perforation in the cervical third of the root is an integral part of dental practice. Orthodontic extrusion preserves the natural root system and may convert the tooth indicated for extraction into useful tooth with good prognosis and a low risk of failure. Orthodontic tooth eruption can be an alternative to treatment such as surgical crown lengthening, especially in esthetic areas, and provides more favorable conditions for prosthodontic coronal restorations by guaranteeing proper sealing and esthetics and preserving periodontal tissue health. The aim of this case report was to explain a multidisciplinary approach that successfully preserve and treat the teeth with subgingival carious lesion. This innovative method is cost-effective and can be easily done with the equipment available in any office.