Comparison of Surface Hardness of Various Shades of Twinky Star Colored Compomer Light-cured with QTH and LED Units

Roughness assessment of colored compomers: Results after an erosive-abrasive in vitro cycling test

Background

The present in vitro study aimed to evaluate and compare the surface roughness of a colored compomer and a composite resin, after 15 days of erosive-abrasive cycling.

Material and Methods

The sample included ninety circular specimens, randomly divided (n = 10): G1 Berry, G2 Gold, G3 Pink, G4 Lemon, G5 Blue, G6 Silver, G7 Orange and G8 Green, referring to the different colors of compomer (Twinky Star®, VOCO, Germany) and G9 for composite resin (Z250®, 3M ESPE). The specimens were submerged in artificial saliva and stored at 37°C for 24 hours. After polishing and finishing, the specimens were submitted to initial roughness (R1). Then, the specimens were submerged in an acidic cola-based drink for 1 minute and then exposed to electric toothbrushing for 2 minutes for 15 days. After this period, the final roughness (R2) and the ΔRa were performed. Data were submitted to ANOVA and Tukey's test for intergroup comparison and paired T-test for intragroup comparison (p<0.05).

Results

Among compomers, the green color presented the higher/lower initial and final roughness values (0.94 ± 0.44, 1.35 ± 0.55) with lemon color presenting the most prominent real roughness increase (ΔRa = 0,74) whereas composite resin showed the lower values (0,17 ± 0.06, 0,31 ± 0.15; ΔRa = 0,14).

Conclusions

All compomers, after the erosive-abrasive challenge, presented an increase in roughness values when compared to composite resin with a highlight to green tones. Key words:Compomers, composite resins, surface properties.

Structural and mechanical analysis of three orthodontic adhesive composites cured with different light units

OBJECTIVE

To evaluate the effects of three different curing units on the physical and mechanical features of three different orthodontic adhesive resin materials.

MATERIAL AND METHODS

45 specimens (5 mm in diameter, and 2 mm in thickness) of each of the three different adhesive composite resin materials (Transbond XT, Grēngloo™ Adhesive and Light Bond Paste) were cured with three different light units (a polywave third generation (Valo), a monowave (DemiUltra), and a second-generation LED (Optima 10)). To quantify degree of conversion (DC), the Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy was used in transmission mode (ALPHA FT-IR Spectrometer, Bruker Optics, Germany). Vickers hardness value was recorded under constant load 100 g for 10 s with a microhardness tester (HMV M-1, Shimadzu Corp., Kyoto, Japan). The data were statistically analyzed using Kruskal-Wallis and chi-square tests. The level of significance was considered p < 0.05.

RESULTS

The highest DC values were obtained as a result of curing with Optima 10. This rate was followed by Demi Ultra and Valo, respectively. Transbond XT samples showed a lower level of conversion than the samples of Light Bond Paste and Grēngloo™ Adhesive. The top surfaces of each material showed higher hardness values than the bottom surfaces (p < 0.05). The Light Bond Paste showed the highest hardness values both on the top and bottom surfaces among the three materials, followed by Grēngloo™ Adhesive. While the hardness values of the top surfaces of the samples cured with Demi Ultra and Valo light units were similar, higher hardness values are recorded with Valo on the bottom surfaces (Valo; 85.200/75.200 (top/bottom) versus Demi Ultra; 86.100/66.000 (top/bottom)).

CONCLUSIONS

The different DC and the surface hardness properties were recorded for the resin as orthodontic adhesives depending on different light units. Shorter radiation time caused lower DC and surface hardness values.

Comparative Evaluation of Retention and Antibacterial Efficacy of Compomer and Glass Hybrid Bulk Fill Restorative Material as a Conservative Adhesive Restoration in Children with Mixed Dentition-An In Vivo Two-arm Parallel-group Double-blinded Randomized Controlled Study

Aim and objective

To compare and evaluate the retention along with antibacterial efficacy of colored compomer and glass hybrid bulk fill glass ionomer restorative material as a conservative adhesive restoration in children of age 6–12 years.

Materials and methods

Sixty children were selected fulfilling the inclusion and exclusion criteria falling in the age group of 6–12 years with mixed dentition and two groups were formed: group I—colored compomer and group II—glass hybrid bulk fill material. Initially, oral prophylaxis was carried out and baseline collection of saliva was completed. Then, the restorative treatment was completed. Retention of the material and antibacterial count [colony-forming units (CFU)/mL of saliva] was estimated at 1, 3, and 6 months after the restorative procedure.

Results

It was seen that retention rate with glass hybrid bulk fill group was 100%, whereas with colored compomer group it was 90% at end of 6 months. Although good antibacterial activity was shown by both the group at 1, 3, and 6 months follow-up but statistically significant drop was seen in the glass hybrid bulk fill group at 3-month intervals than the colored compomer group with a p value of 0.0001 (p < 0.05).

Conclusion

Among both the materials, glass hybrid bulk fill restorative material showed good retention compared to Colored compomer material but it was not statistically very significant. Also, both the materials have shown good antimicrobial activity at 1, 3, and 6 months follow-up.

How to cite this article

Mundada MV, Hugar SM, Hallikerimath S, et al. Comparative Evaluation of Retention and Antibacterial Efficacy of Compomer and Glass Hybrid Bulk Fill Restorative Material as a Conservative Adhesive Restoration in Children with Mixed Dentition—An In Vivo Two-arm Parallel-group Double-blinded Randomized Controlled Study. Int J Clin Pediatr Dent 2020;13(S-1):S45–S54.

Temperature change in pulp chamber of primary teeth during curing of coloured compomers: an in vitro study using pulpal blood microcirculation model

Introduction

An increase in the temperature of the pulp chamber occurs during polymerisation of all types of light-curing resin-containing restorative materials, due to both the exothermic reaction of the material and the energy absorbed during the curing process. Increase in temperature of the pulp chamber of primary teeth during the curing process or the thermal conductivity properties of coloured compomers (CCs) have not yet been investigated in detail. The aim of the present study was to investigate the increase in pulpal temperature in primary teeth during curing of CCs.

Materials and Methods

A Class-II cavity was prepared on the extracted primary mandibular second molar. Pulpal microcirculation of the tooth was performed using an experimental mechanism. The study included 15 groups and 10 experiments in each. Seven different CCs: pink, blue, gold, silver, orange, lemon, green, respectively from two different manufacturers (Groups 1–7: Twinky Star; VOCO, Cuxhaven, Germany. Groups 8–14: Nova Rainbow; IMICRYL, Konya, Turkey.) and a tooth-CC (Group 15: Dyract XP; DENTSPLY, Weybridge, UK.) were applied in prepared cavity. In all groups the compomers were light cured for 40 s. Intrapulpal temperature changes (Δt) in 20th and 40th second were recorded. In Group-15 the Δt values in 10th second were also recorded as per the manufacturer’s instructions. The Kruskal–Wallis test and the Mann–Whitney-U test were used for statistical analyses.

Results

At the end of 40-s irradiation time, the orange, lemon and green colours of Nova Rainbow resulted in significantly lower Δt values than the same colours of Twinky Star (p = 0.0001), and silver, blue, lemon, green, orange, and pink CCs of Nova Rainbow and the blue and silver shades of Twinky Star demonstrated lower Δt values than the reported critical temperature increase (5.5 °C).

Conclusion

An increase in the irradiation time consequently led to an increase in the intrapulpal temperature. Therefore, manufacturers should focus on production of new CCs with shorter polimerization time.

Polymerization characteristics of colored compomers cured with different LED units

Aim:

Incomplete polymerization of a resin material used for dental restoration affects the properties of the restoration. We evaluated the structural and mechanical properties of three different colored compomers cured with three different LED units to observe the characteristic changes occurring in different matches.

Methods:

Polytetrafluoroethylene molds (5 mm in diameter and 2 mm in thickness) were used to prepare disk-shaped sample specimens. Nine sample groups (each of five specimens) were prepared, three each of different compomer resin colors (gold, berry, and silver). Samples were cured using three different LED units (Optima, VALO, and Demi Ultra), according to the manufacturers’ instructions. Microstructural properties of samples were characterized by determining the degree of curing using Fourier-transform infrared spectroscopy and by analyzing sample morphology under a scanning electron microscope. The Vickers hardness, compressive strength, and elastic modulus of the samples were measured to investigate their mechanical properties.

Results:

The degrees of curing decreased in the order of silver > berry > gold for all curing units. Conversely, gold compomers exhibited poorer mechanical values than the berry and silver counterparts. The Optima 10 unit yielded slightly higher degrees of curing than the other devices, followed by Demi Ultra and VALO light-curing units, respectively.

Conclusion:

The resin color affected the structural and mechanical properties of the compomers, possibly as a result of the complex interactions and relationships between the irradiation light and resin material, such as light absorbance and reflectance; thus, depending on the color as well as the curing protocol.