Effect of Newer Intraorifice Barriers on the Fracture Resistance of Endodontically Treated Teeth: An In Vitro Study.

AIM: This study aimed to assess and compare the fracture resistance of endodontically treated teeth using three new intraorifice barrier materials. MATERIALS AND METHODS: A total of 60 extracted human mandibular premolars having single roots were decoronated to 14 mm length, prepared up to rotary F3 ProTaper Gold files, and sealed with gutta-percha and AH Plus sealer. Specimens were divided into one control and three experimental groups (n  = 15): Group 1, control; Group 2, Biodentine (Septodont, Saint Maur des Fosses, France); Group 3, resin-modified glass ionomer cement (RMGIC, GC Gold Label 2 LC, GC Corporation, Tokyo, Japan); and Group 4, flowable nanohybrid composite (G-aenial Universal Flo, GC Corporation, Tokyo, Japan). A 3 mm coronal gutta-percha was replaced with respective intraorifice barrier materials in the experimental groups, and the fracture resistance of all the groups was tested using the universal testing machine. STATISTICAL ANALYSIS: One-way analysis of variance and Tukey's post-hoc test were conducted. RESULTS: The experimental groups showed higher mean load values than the control group. The flowable composite showed the highest mean loads followed by Biodentine and RMGIC. The mean fracture resistance of flowable nanohybrid composite and Biodentine was significantly higher than that of the control. No statistically significant difference was observed among the other groups. CONCLUSION: The flowable nanohybrid composite and Biodentine significantly improved resistance to fracture of endodontically treated teeth when compared to the control.

Spectrophotometric evaluation of color stability of novel composites following exposure to antioxidant beverages: An in vitro study.

Background: Color matching and stability are the essential considerations in restorative dentistry, as they contribute to the longevity and esthetic appeal of the restorations. Composites with nanoparticles and more filler content are anticipated to be more color-stable. Aim: The aim of the study was to assess and contrast the color stability of esthetic restoration materials following exposure to various antioxidant beverages. Materials and Methods: A Class V cavity was prepared on the buccal surface of 40 maxillary premolars. The specimens were divided into two groups: microhybrid (MH) and nanohybrid (NH) composite. The baseline color of each tooth sample was measured and then, the samples were categorized into four subgroups based on the immersion solution (pomegranate juice, beetroot juice, black plum juice, and distilled water) and evaluated on day 1, day 7, day 14, and day 21 using a spectrophotometer-based on CIE L*a*b* color scale. For spectrophotometer analysis, CIE XYZ data were obtained and converted to CIELAB. The samples mean difference in ΔE values before and after being immersed in various beverages. Statistical Analysis: The data were statistically analyzed using an independent t-test and one-way analysis of variance. Results: MH and NH composite materials showed color change after being exposed to the test beverages. Conclusion: MH composite causes more color change than NH composite at all-time intervals. Black plum showed the greatest discoloration in both composites.

Effect of Multivitamins on the Color Stability of Dental Materials Used in Pediatric Dentistry: An In Vitro Study.

The longevity and acceptance of aesthetic dental materials are directly proportional to color stability. The aim of this study was to analyze the relationship between the use of multivitamins and the color stability of dental restorative materials. A total of 45 discs of nanohybrid composite, 45 of Reinforced Glass Ionomer (RGI), and 45 of Giomer were prepared. Subsequently, the samples were randomly divided into three solution groups (n = 15): Group 1-Sambucol Pediatric Syrup, Group 2-Hidropolivital Baby Drops, and Group 3-artificial saliva, which is preparation for patients with xerostomia. For 28 days, the specimens were immersed in 10 mL of each multivitamin for two minutes every 24 h. Color measurements were repeated on days 7, 14, 21, and 28. Statistical analysis was performed using the Jamovi software version 2.2.5, employing the Shapiro-Wilk test for normality and the Kruskal-Wallis test for non-parametric data. When comparing materials, statistically significant differences (p < 0.001) were observed between RGI and Giomer, and RGI and composite, but not between Giomer and composite (p = 0.716). The highest change was observed in RGI-Hidropolivital ΔE00 = 3.27 (2.38-4.59) and the least in composite-Sambucol ΔE00 = 0.72 (0.30-1.18). In conclusion, the exposure time and the multivitamin influence the color change of restorative materials.

Comparative Spectrophotometric Assessment of Color Stability of Two Hybrid Composite Materials in an Oral Environment when Exposed to Various Liquids.

Introduction: The primary intent of this scientific research is to effectively assess and collate the inherent potentiality of the two selected investigative composite materials in effectual maintenance of their standard color following subsequent and consistent submersion in customary available pediatric liquids consumed by children. The above investigation will be effectively estimated using the Commission Internationale de I'Eclairege (CIE) L*a*b* system-based spectrophotometer. Materials and methods: A total of 100 composites of spheroidal plates were fabricated accordingly. A total of 50 nanohybrids and microhybrids of 8 × 2 mm were fabricated and timely cured using a light cure unit for an approximated time period of 40 seconds. This was then trialled by subsequent sample submersion in the specified five immersive media, which include mineral water, tea, Mirinda, pomegranate juice, and iron syrup, respectively, for a definitive and habitual time of thrice daily up to 15 minutes for a duration of 28 experimental days. The respective marked readings were recorded on the 7th, 14th, 21st, and 28th days by utilization of a CIE L*a*b* system-based spectrophotometer. Results: Mann-Whitney U test and Friedman's Test were utilized for statistical evaluation of the above-described experimental research. The p-value was statistically found to be significant at (p < 0.001). Conclusion: The conclusive findings from the above-defined experimental research were that iron syrup was found to cause the most noticeable and definitive staining in comparison to other immersive media. Nanohybrid composite restorative material was hence identified as being highly resistant to staining and possessing an undeniable ability to maintain the persistent color, unlike its microhybrid counterpart. Clinical significance: The esthetic appearance is an important factor for both the parents and children; hence, this determines that the longevity of color stability of restorative materials is of valid significance. How to cite this article: Thribhuvanan L, MS S, Gopalakrishnan A, et al. Comparative Spectrophotometric Assessment of Color Stability of Two Hybrid Composite Materials in an Oral Environment when Exposed to Various Liquids. Int J Clin Pediatr Dent 2024;17(2):176-183.

Water Sorption and Solubility of Highly Aesthetic Single-Shade Nano-Hybrid Resin Composites.

Background A single-shade resin composite is a new type of resin composite that was introduced in 2019. There is not much data regarding the water sorption (Wsp) and water solubility (Wsl) of this type of resin composite. Therefore, this study aimed to investigate Wsp and Wsl and their effects on the surface roughness of a single-shade nano-hybrid resin composite in comparison with a conventional nano-hybrid resin composite in accordance with ISO 4049:2019 (Dentistry - Polymer-based Restorative Materials). Material and methods An in vitro study was performed to investigate the Wsp and Wsl of a single-shade supra-nano-hybrid composite (Omnichroma) and a conventional nano-hybrid composite (Filtek™ Z250 XT) in accordance with ISO 4049:2019. Five disks were prepared of each material with dimensions of 15 ± 1 mm in diameter and 1 ± 0.1 mm in thickness, as per ISO 4049:2019. The results were calculated according to the ISO equations for Wsp and Wsl in µg/mm3. Atomic force microscopy (AFM) was used to analyze the surface roughness (Ra) of test specimens. Results The findings showed that the values of Wsl and Wsp of both materials are comparable and revealed no statistically significant difference (P > 0.05). The AFM images showed a higher Ra post-solubility testing, and the statistical analysis indicated a significant difference for both materials. Conclusions The study concluded that the single-shade resin composite (Omnichroma) and the conventional nano-hybrid composite (Filtek™ Z250 XT) are following the requirements of ISO 4049:2019. The AFM analysis indicated that resin composite surfaces are significantly affected when exposed to water for a prolonged period of time. However, the Ra variations of Filtek™ Z250 XT were higher than Omnichroma specimens. These results indicate that resin composite surfaces can be significantly impacted by prolonged water exposure. This knowledge is critical for enhancing the long-term clinical performance and durability of these dental restorative materials.

Effect of phytopigments on discoloration of nanohybrid composite: An in vitro study.

Objective: The purpose of this study is to comparatively evaluate the effect of discoloration of nanohybrid composite by four different phytopigments. Materials and Methods: Fifty disk-shaped samples of nanohybrid (3M Filtek Z350) resin composites were prepared using an acrylic template of dimension 5 mm × 3 mm. They were randomly divided into five groups and immersed in solutions of tomato powder, beetroot powder, java plum powder, and turmeric powder. Distilled water was used as the control group. The samples were placed in respective solutions for 3 h daily and stored in artificial saliva for the rest of the day for 28 days. Color values (L*, a*, b*) were measured by colorimeter using the CIE L*a*b* system at the end of the 7th and 28th days of immersion. Color differences ΔE*ab were statistically analyzed. Results: All the samples showed a change in color of nanohybrid composite resin to varying degrees. The mean ΔE*ab value obtained with beetroot solution was the highest among all the groups at the end of the 7th and 28th days, depicting that beetroot solution showed maximum mean color variation, followed by java plum solution, turmeric solution, and tomato solution. Conclusion: All the phytopigments used in this study have the potential to discolor the nanohybrid composite resin, with beetroot causing the most severe discoloration.

In vitro study on the impact of various polishing systems and coffee staining on the color stability of bleach-shaded resin composite.

OBJECTIVE: To evaluate the effects of different polishing techniques and coffee staining on the color stability of four commercially available bleach-shade composite resins, namely microhybrid, nanohybrid, nanofilled, and injectable nanohybrids. MATERIAL AND METHODS: A total of 224 discs (8 mm diameter and 2 mm thickness) were fabricated from four different bleach-shade composite resins, namely microhybrid (Gradia Direct Anterior), nanohybrid (Palfique LX5), nanofilled (Filtek Universal), and injectable nanohybrid (flowable G-aenial universal injectable). The composite resin groups were polished via four techniques: no polishing, 4-step polishing using aluminum oxide discs, 3-step polishing using silicon rubber diamond discs, and one-step polishing. Half of each group was immersed in water, while the other half was immersed in coffee for 12 days (n = 7). Colors were measured using a clinical spectrophotometer, and color differences were calculated (ΔE). The results were analyzed statistically. RESULTS: The alterations in color were significantly influenced by the techniques employed for finishing and polishing techniques, composite resin type, and degree of coffee staining. Regardless of the polishing technique and storage medium, different material types showed a significant color change (ΔE) at P < 0.001. Filtek exhibited the most significant color change, followed by Gradia and Palfique, with no significant differences between them. In addition, Different polishing techniques resulted in significant color changes (P < 0.001). The highest degree of color change was seen in the no-polishing group, followed by the 4-step and 1-step polishing groups, with negligible differences between each other. Also, Storage media had a significant effect on ΔE values. CONCLUSION: Appropriate finishing and polishing procedures can improve the color stability of bleach-shaded composite resins. Coffee has a deleterious effect on color; however, injectable flowable nanohybrid composites are more resistant to staining.

Influence of Cavity Lining on the 3-Year Clinical Outcome of Posterior Composite Restorations: A Randomized Controlled Clinical Trial.

The purpose of this randomized, split-mouth-designed controlled and single-blinded clinical study was to evaluate the 3-year clinical performance of Class I and Class II resin composite restorations placed with or without cavity lining with a flowable composite. Fifty patients with treatment needs in two premolars or molars were included. One of the teeth was restored using the nanohybrid composite (Grandio®SO, control group), in the test group a high viscosity flowable composite was additionally applied as a first layer. In both groups, the same self-etch adhesive system was applied. Clinical evaluation after 3 years was carried out using the modified USPHS/Ryge criteria. At the 3-year follow-up the recall rate was 92%. Four restorations failed in the test group (8.7%), three due to the loss of vitality and one after fracture. The control group exhibited a cumulative success rate of 100%, while the test group achieved a success rate of 91.3%. This led to significant differences in the annual failure rate (AFR) between the two groups, with rates of 0% and 2.9% (p < 0.05; Mann-Whitney U-test). After 3 years the cumulative survival rate including all restorations was 95.7%. Statistical analysis revealed significant differences for the parameters: tooth vitality, marginal discoloration, success rate, and AFR. The other parameters exhibited no significant differences. Consequently, the nanohybrid composite demonstrated excellent performance over a 3-year period, whereas the utilization of a flowable composite for the cavity lining did not appear to exert a beneficial influence on clinical outcomes.

Color Stability of Bioactive Restorative Material vs Nanohybrid Resin Composite: An In Vitro Study.

AIM: This study aimed to assess the color stability of bioactive restorative materials vs nanohybrid resin composites after 3 months of immersion in three frequently consumed beverages. MATERIALS AND METHODS: Thirty disk-shaped specimens of Giomer dental restorative material (Shofu, Japan) and nanohybrid resin composite (Tokuyama, Japan) were performed using a Teflon mold. Super-Snap system (Shofu, Japan) was utilized to finish and polish the specimens to be preserved for 24 hours in distilled water at 37°C. The samples had been divided into three subgroups (Coffee, tea, Pepsi) (n = 5). The initially displayed color measurements of the samples were performed using a spectrophotometer (VITA Easyshade® V). After 7 days, 30 days, and 90 days, color measurements were repeated, and the E of each sample was estimated. E of each sample was calculated. RESULTS: The Giomer group showed statistically significant higher E values than the nanohybrid resin composite where the p-value was ≤0.0001. Tea subgroup showed the highest statistically significant E values in both groups where the p-value was ≤ 0.0001. The highest statistically significant color change was recorded at 3 months. CONCLUSION: The color of bioactive restorative material is less stable if compared with nanohybrid resin composite. CLINICAL SIGNIFICANCE: As tea and coffee are popular beverages, particularly in Middle Eastern nations, dentists must advise patients about the color change of resin restorations. Patients are advised to brush their teeth immediately after consuming these beverages. How to cite this article: Saber EH, Abielhassan MH, Abed YA, et al. Color Stability of Bioactive Restorative Material vs Nanohybrid Resin Composite: An In Vitro Study. J Contemp Dent Pract 2024;25(3):221-225.

Investigation of the Surface Roughness and Hardness of Different Denture Teeth Materials: An In vitro Study.

Background: Surface roughness and hardness are key factors that influence the clinical performance and durability of denture teeth. Understanding variations in these properties among different denture teeth materials can assist in selecting the most suitable materials for optimal patient outcomes. This study aimed to investigate the surface roughness and hardness of four commonly used denture teeth materials: acrylic resin, composite resin, porcelain, and nanohybrid composite. Materials and Methods: Ten specimens were prepared for each denture teeth material, resulting in a total of 40 specimens. Surface roughness was assessed using a profilometer, and measurements were recorded in micrometers (µm). Hardness was determined using a Vickers hardness tester, and results were expressed as Vickers hardness numbers (VHN). The surface roughness and hardness data were analyzed using appropriate statistical tests (e.g., analysis of variance), with significance set at P < 0.05. Results: The results revealed significant differences in both surface roughness and hardness among the different denture teeth materials (P < 0.05). Acrylic resin exhibited the highest surface roughness (mean ± standard deviation: 3.45 ± 0.78 µm) and the lowest hardness (mean ± standard deviation: 45.6 ± 2.3 VHN). Composite resin demonstrated intermediate values of surface roughness (mean ± standard deviation: 1.87 ± 0.54 µm) and hardness (mean ± standard deviation: 65.2 ± 3.9 VHN). Porcelain demonstrated the smoothest surface (mean ± standard deviation: 0.94 ± 0.28 µm) and the highest hardness (mean ± standard deviation: 78.5 ± 4.1 VHN). Nanohybrid composite displayed surface roughness and hardness values similar to composite resin. Conclusion: This study demonstrated significant variations in surface roughness and hardness among the different denture teeth materials evaluated. Acrylic resin exhibited the roughest surface and lowest hardness, while porcelain demonstrated the smoothest surface and highest hardness. Composite resin and nanohybrid composite exhibited intermediate values. These findings provide valuable insights for prosthodontic practitioners in selecting denture teeth materials based on specific clinical requirements, aiming to achieve optimal aesthetics, reduced plaque accumulation, and improved wear resistance.

The Evaluation of the Cervical Marginal Sealing of Direct vs. Indirect Composite Resin Restorations in MOD Cavities.

INTRODUCTION: The aim of this in vitro study was to compare the quality of marginal sealing at the cervical margins of indirect and direct composite resin restorations in mesio-occluso-distal (MOD) cavities. MATERIAL AND METHOD: MOD preparations were performed on 30 extracted teeth. The mesial cervical margin of each tooth was relocated using a flow composite resin (Enamel Plus HRi Flow, Micerium, Avegno, GE, Italy), then the samples were divided into three groups. In group A, the cavities were directly restored using a nanohybrid composite resin (Miris 2 Coltène Whaledent, Altstaetten, Switzerland) and a universal adhesive (ScotchBond Universal, 3M ESPE, St. Paul, MN, USA) by the etch-and-rinse strategy, for group B, the restoration procedure was similar but the self-etch strategy was used, and the samples in group C were filled using the inlay technique. Each sample was stored for 48 h in a 2% methylene blue solution, then it was cut in a mesio-distal direction using a Struers Secotom 50 device (Cleveland, OH, USA). The marginal sealing and adhesive interface were assessed for each sample at the cervical margin by optical microscopy (OM) and scanning electron microscopy (SEM). One-way ANOVA and Bonferroni post-hoc tests were used with a significance level of 0.05. RESULTS: Significant differences were recorded within groups A and C, between mesial and distal margins (p = 0.02 in group A and p = 0.043 in group C). CONCLUSIONS: The marginal sealing is more effective in MOD inlay restoration compared to direct restorations. Relocation of the cervical margin with flow composite resin and the use of different adhesive strategies do not improve the marginal sealing.

Effect of dentin roughening and type of composite material on the restoration of non-carious cervical lesions: an in vivo study with 18 months of follow-up.

Objectives: The purpose of this study was to evaluate the impact of dentin roughening and the type of composite resin used (either bulk-fill flowable or nanohybrid) on the restoration of non-carious cervical lesions (NCCLs) with an 18-month follow-up period. Materials and Methods: This prospective split-mouth study included 36 patients, each with a minimum of 4 NCCLs. For each patient, 4 types of restorations were performed: unroughened dentin with nanohybrid composite, unroughened dentin with bulk-fill flowable composite, roughened dentin with nanohybrid composite, and roughened dentin with bulk-fill flowable composite. A universal bonding agent (Tetric N Bond Universal) was applied in self-etch mode for all groups. The restorations were subsequently evaluated at 6, 12, and 18 months in accordance with the criteria set by the FDI World Dental Federation. Inferential statistics were computed using the Friedman test, with the level of statistical significance established at 0.05. Results: The 4 groups exhibited no significant differences in relation to fracture and retention, marginal staining, marginal adaptation, postoperative hypersensitivity, or the recurrence of caries at any follow-up point. Conclusions: Within the limitations of the present study, over an 18-month follow-up period, no significant difference was present in the clinical performance of bulk-fill flowable and nanohybrid composite restorations of non-carious cervical lesions. This held true regardless of whether dentin roughening was performed.

An In Vitro Staining Effect of Different Children's Health Drinks on Esthetic Restorative Materials.

Aim: To evaluate the staining effect of different children's health drinks (Boost, Complan, and Pediasure) on esthetic restorative materials (giomer, nanohybrid composite, and ormocer). Materials and methods: The specimens consist of giomer, nanohybrid composite, and ormocer. Before the discoloration process, 80 disks of each material were fabricated, each measuring 5 mm in diameter and 2 mm in thickness. These disks were then measured for lightness*red/green*blue/yellow (L*a*b*) values. Around 10 samples from each subgroup were then submerged in each of the four staining solutions. Analysis of discoloration levels was done at baseline and 48 hours after immersion in the staining solution. Each specimen's staining effect was evaluated using a spectrophotometer.Each specimen's L*a*b* values were measured three times by placing it on the measurement head. The internal energy (ΔE) unit, which expresses resistance to the staining effect, was derived using each specimen's L*a*b* values. Results: All the tested materials showed a color change. However, giomer showed greater ΔE values compared to nanohybrid composite and ormocer. Of all the immersion media used, Boost samples resulted in the highest color change, followed by Complan, Pediasure, and milk. Conclusion: Out of the three restorative materials used in the study, ormocer showed more resistance to color change than nanohybrid composite and giomer with all the tested media. How to cite this article: Ponnala SL, Punithavathy R, Birapu UKC, et al. An In Vitro Staining Effect of Different Children's Health Drinks on Esthetic Restorative Materials. Int J Clin Pediatr Dent 2023;16(2):211-217.

Effects of Dental Bleaching Agents on the Surface Roughness of Dental Restoration Materials.

Background and Objectives: This study aimed to evaluate the surface roughness evolution of several finished and polished composites when bleaching materials are applied. The research was conducted on four microhybrid or nanofilled composites that are used in dental restorations. Materials and Methods: For each composite type, 5 samples were selected for control, 5 samples were subjected to the bleaching protocol "office bleach" with 40% hydrogen peroxide, and 5 other samples were subjected to the "home bleach" protocol with 16% carbamide peroxide, resulting in a total number of 60 samples. The surfaces of all the samples were tested for roughness, and the values of the most relevant parameter (Ra), were collected. Comparisons between composites and samples were performed using one-way ANOVA (in Statistical Package for Social Sciences). Results: After the bleaching protocol with 40% hydrogen peroxide gel, it was found that the roughness of the group increased considerably compared to the control group, so the highest roughness was found at GC Gradia direct anterior group, and the lowest value was registered for the 3M ESPE Valux Plus group. Following the bleaching protocol with 16% carbamide peroxide (home bleach), it was noted that the sample surfaces were not as affected. In this case, the lowest roughness was found at 3M ESPE Valux Plus group, and the highest roughness was registered for the GC G-aenial anterior group. Following the interpretation of the results, all four types of dental composites tested showed significant surface roughness differences between the groups subjected to bleaching protocols and those kept as control (p < 0.05). Conclusions: The surfaces of the samples were affected by the bleaching protocols by increasing the roughness compared to the control samples.

In Vitro Color Stability Evaluation of Three Polished and Unpolished Nanohybrid Resin Composites Immersed in a 0.12% Chlorhexidine-Based Mouthwash at Different Times.

The use of chlorhexidine-based mouthwashes on resin composites with rough surfaces can cause discoloration which compromises the esthetic of patients. The present study aimed to evaluate the in vitro color stability of Forma (Ultradent Products, Inc., South Jordan), Tetric N-Ceram (Ivoclar Vivadent, Schaan, Liechtenstein) and Filtek Z350XT (3M, ESPE, St. Paul, MN, USA) resin composites, with and without polishing, after being immersed in a 0.12% chlorhexidine (CHX)-based mouthwash at different times. The present in vitro experimental and longitudinal study used 96 nanohybrid resin composite blocks (Forma, Tetric N-Ceram and Filtek Z350XT) 8 mm in diameter and 2 mm thick, evenly distributed. Each resin composite group was divided into two subgroups (n = 16) with and without polishing and then immersed in a 0.12% CHX-based mouthwash for 7, 14, 21 and 28 days. Color measurements were performed with a calibrated digital spectrophotometer. Nonparametric tests were used to compare independent (Mann-Whitney U and Kruskal-Wallis) and related (Friedman) measures. In addition, the Bonferroni post hoc correction was used considering a significance level of p < 0.05. All polished and unpolished resin composites presented color variation < 3.3 when immersed for up to 14 days in 0.12% CHX-based mouthwash. The polished resin composite with the lowest color variation (ΔE) values over time was Forma, and the one with the highest values was Tetric N-Ceram. When comparing the color variation (ΔE) over time, it was observed that the three resin composites, with and without polishing, presented a significant change (p < 0.001), although these changes in color variation (ΔE) were evident from 14 days between each color acquisition (p < 0.05). The unpolished Forma and Filtek Z350XT resin composites showed significantly more color variation than the same polished ones at all times when immersed in a 0.12% CHX-based mouthwash for 30 s daily. In addition, every 14 days, all three resin composites with and without polishing showed a significant color change, while, every 7 days, color stability was maintained. All the resin composites showed clinically acceptable color stability when exposed for up to 14 days to the above-mentioned mouthwash.

Survival and success of composite resin restorations in endodontically treated maxillary incisors with minimal structure loss.

The primary aim of this study was to evaluate the clinical performance of nanofilled composite resin restorations in traumatized, endodontically treated maxillary incisors with structural loss of 40% or less. The performance of the restorations was assessed in terms of longevity (survival) and esthetics (success) over a 20-month period. The secondary objective was to employ a novel digital method to quantify preoperative tooth structure loss. Sixty-one fractured maxillary incisors in 55 patients were included in the study. The teeth were photographed with a digital single-lens reflex camera equipped with a macro ring flash. The amount of lost tooth structure was calculated with digital photography software. The teeth were restored with a nanohybrid composite resin and self-etching adhesive system bonding agent. To assess esthetics, color change in the blue-yellow axis (Δb*) of the composite resin restoration was evaluated digitally with the Commission Internationale de l'Eclairage (CIE) L*a*b color system. The Wilcoxon signed-rank test was used to assess Δb*, and a Kaplan-Meier survival analysis was used to assess the longevity of the restorations. The study findings showed a statistically significant difference between pretreatment and posttreatment b* values (P < 0.05), but the difference was too small to be clinically perceptible to the human eye. A total of 5 restorations (9.8%) failed. The remaining restorations survived for a mean (SD) period of 18.6 (4.4) months. The log-rank test did not show any significant association between the amount of residual tooth structure and success of the restoration. The results of this study showed that use of direct composite resin restorations in endodontically treated maxillary incisors resulted in acceptable survival and success rates. Trial registration: Clinical Trial Registry of India No. CTRI/2020/01/023019.

The effect of different energy levels of the Er: YAG laser on the repair bond strength of a nanohybrid composite resin.

This study evaluates the durability of repair microshear bond strength (µSBS) of nanohybrid composite resins which surfaces are treated with different laser parameters and bur. A total of 240 nanohybrid composite resin disk shaped specimens were prepared. Then, specimens were divided into eight test groups as regards to surface treatment types (Erbium (Er:YAG) laser with seven different parameters and bur). Half of the specimens in each group were subjected to 5000 thermal cycling (TC) and the other half to 20,000 TC. Universal testing machine was used for µSBS test. The data were analyzed with a two-way analysis of variance and Tukey test. Among the specimens treated with ER:YAG laser+5000 TC, we detected the highest mean µSBS test values in the subgroups L200 and L250. Among the specimens treated with ER:YAG laser+20,000 TC, the highest mean µSBS test values were seen in the L200 subgroup. The µSBS values after the 20,000 TC were significantly lower than those after 5000 TC for all different treatment types. Thermal cycling and laser energy levels have effects on repair µSBS. Considering the bond strength and durability it seems more effective to use Er:YAG laser at 200 mJ. To repair an aged nanohybrid composite resin, Er:YAG laser surface treatments may provide some benefits by acquiring a reliable bond strength with durability. This study may give information on which parameters are more suitable to use Er:YAG laser for the repair of nanohybrid composite resins.

Comparative Evaluation of Shear Bond Strength of Nanohybrid Composite Restoration After the Placement of Flowable Compomer and Composite Using the Snowplow Technique.

AIM: Based on the importance of bonding during restoration, this in vitro study aimed to evaluate the difference in shear bond strength of nanohybrid composite restoration in molars after the placement of flowable compomer and composite using the snowplow technique. MATERIALS AND METHODS: Twenty-four freshly extracted molars were taken and sectioned at the level of 2.5 mm from the coronal cusp and root tip. These sections were embedded in methacrylate and, after etching and bonding, were randomly divided into two groups (n=12) for placement of restorative materials. In group A, the plastic tube was filled with uncured flowable composite resin followed by the placement of packable nanohybrid composite in oblique increments. In group B, the plastic tube was filled with uncured flowable compomer followed by the placement of packable nanohybrid composite in oblique increments. Each specimen was then tested under a universal testing machine to determine the shear bond strength. RESULTS: Independent sample 't' test revealed a statistically significant difference between the mean shear bond strength of compomer and composite (P value<0.001), where flowable composite showed higher values compared to compomer.  Conclusion: It was seen that the use of composite showed a significantly better bond strength of the restoration when compared to compomer using the snowplow technique. Both materials and application techniques can influence the bond strength of a material as determined in this study.

Effect of Different Surface Treatments on Repair Bond Strength of CAD/CAM Resin-Matrix Ceramics.

The purpose of this study was to investigate the influence of different surface treatment methods on the micro-tensile bond strength (µTBS) of resin-matrix ceramic (RMC) blocks repaired with resin composite. Three different prefabricated RMC blocks including Lava Ultimate (LU), Grandio Blocs (GB), and Shofu Block HC (HC) were thermo-cycled and divided into five surface treatment groups: Control (C), bur grinding (G), airborne particle abrasion (APA), Er,Cr:YSGG laser irritation (LI), and APA combined with LI (APA+LI). After surface treatments, topographic alterations were examined by scanning electron microscopy. Then, Universal Adhesive (Single Bond Universal) was applied and repair was simulated with nanohybrid composite (Grandio SO). Bonded specimens were cut into 1 mm2 sized beams (n = 16) and a µTBS test was conducted by using a universal test machine. Fracture types were evaluated by using a stereomicroscope. The bond- strength data was evaluated by two-way ANOVA and Tukey post-hoc test (α = 0.05). The µTBS values were significantly affected by the surface treatment variable and the interaction terms of the variables (p ≤ 0.001). However, no significant effect of RMC type was detected (p > 0.05). Among all materials, GBAPA+LI indicated the highest µTBS value. Except for the GBC, all surface treatments showed clinically acceptable bond-strength values. However, the surface treatments applied to GB and LU before the repair processes increased the repair bond-strength values while causing a negative effect for HC. In addition, LI and APA+LI can be applied as an alternative route compared to other procedures recommended by the manufacturer for surface preparation in intraoral RMC repair.

Evaluation of titanium mesh and fibers in reinforcing endodontically treated molars: An in vitro study.

Aim/Objective: We aimed to evaluate the fracture resistance of titanium mesh and fibers that could aid as a substitute for crown coverage. Materials and Methodology: Forty extracted human mandibular molar teeth were selected for this study and were divided into four groups (n = 10). Access cavity preparation was done in all experimental teeth (Groups 2-4) maintaining 1.2-1.5 mm diameter of tooth structure around the circumference to mimic the structural loss of teeth due to the extent of dental caries. Group 1 consisted of intact teeth which were assigned as control. Group 2 was reinforced with titanium mesh. Group 3 was reinforced with glass fiber. Group 4 was reinforced with polyethylene fiber. The access cavities in all the experimental teeth were later filled with nanohybrid composite and were subjected to fracture resistance using a universal testing machine. Results: The results of the study were evaluated statistically using the Kruskal-Wallis test. There was no statistically significant difference among the experimental and control groups. Conclusion: Within the constraint of this in vitro study, an inference can be given that fiber-reinforced composite and titanium mesh could rule out the mandatory procedure of crown placement for endodontically treated molars.