A Comparative Evaluation of Marginal Leakage of Different Restorative Materials in Deciduous Molars: An in vitro Study

Green Synthesis and Investigation of Antimicrobial Activity and Compressive Resilience of Glass Ionomer Cement Modified With Zirconia Nanoparticles: An In Vitro Study

Background Glass ionomer cement (GIC) serves as a crucial biomaterial in dental restoration, offering applications in filling, lining, and adhesive procedures. Nevertheless, its mechanical properties often fall short, particularly in regions subjected to considerable stress. To address this issue, zirconia nanoparticles are incorporated at specific levels. Aim To assess the antimicrobial efficacy and compressive resilience of GIC modified with zirconia nanoparticles synthesized through green synthesis methods. Material and methods Zirconia nanoparticles were synthesized via a green method utilizing aloe vera extract in solvent form. These nanoparticles were then mixed into GIC at different concentration levels. Group I incorporated zirconia nanoparticles at a concentration of 3%, Group II at 5%, and Group III at 10%, while Group IV was the control, consisting of traditional GIC. Following that, samples were prepared and underwent characterization through various analytical techniques. The ability to inhibit microbial growth and the compressive resilience of the groups were examined. Microbial inhibition against the bacterial strains was assessed through minimum inhibitory concentration (MIC), and the ability to withstand compression was gauged by measuring the maximum force the specimen could endure before fracturing. Data underwent analysis with Statistical Package for the Social Sciences (IBM SPSS Statistics for Windows, IBM Corp., Version 24.0, Armonk, NY). Repeated measures of analysis of variance (ANOVA) were utilized to gauge average MIC values and compressive strength. Following this, Tukey's post hoc test was employed for pairwise comparisons. Results The findings indicated, incorporating zirconia nanoparticles into GIC led to an improvement in its antimicrobial effectiveness, with a noticeable enhancement observed as the weight percent (% wt) of the additive increased. This improvement was notably noticeable in its effectiveness against Streptococcus mutans and Lactobacillus, exceeding that of the control with a noteworthy distinction. Furthermore, there were significant enhancements in compressive strength, in Group I (180.48 ± 1.02), Group II (191.25 ± 0.52), and Group III (197.52 ± 0.75), compared to Group IV (167.22 ± 1.235), with significant disparities (p < 0.05). Conclusion The research illustrates that introducing green-synthesized zirconia nanoparticles into GIC leads to heightened bactericidal potency and compressive resilience when contrasted with the control group (Group IV). Notably, the highest concentration of 10% demonstrated the most favourable antimicrobial attributes alongside enhanced strength. Consequently, integrating green-synthesized zirconia nanoparticles into GIC holds potential as a proficient material. In future studies, there should be an exploration of molecular chemistry and bonding mechanisms to enhance our comprehension of its capabilities.

Comparative Assessment of Marginal Micro Leakage of Different Esthetic Restorative Materials Used on Primary Teeth: An In-vitro Study

AIM

The aim of the current investigation was to evaluate the marginal microleakage of various esthetic restorative materials applied to primary teeth.

MATERIALS AND METHODS

A total of 75 noncarious primary molars that were removed for orthodontic intervention and teeth nearing exfoliation were chosen. One millimeter (mm) above the cementoenamel junction, on the buccal surface of the teeth, Class V cavities were prepared. William's graded periodontal probe was used to standardize cavity preparation on all teeth. 3 mm was the cavity's length, 2 mm in width, and 2 mm in depth. The teeth were then divided into three groups (25 samples in each group) according to the type of esthetic restorative material used. Group I: Resin-modified glass ionomer cement, Group II: Ormocer, Group III: Giomer. The samples underwent 500 cycles of thermocycling, with an immersion time of 60 seconds and a well time of 15 seconds, between 5 and 55°C. The samples were submerged in methylene blue dye for 24 hours at room temperature and dried. The samples were then divided into sections and examined with a stereomicroscope. Data was recorded and statistically analyzed.

RESULTS

The least marginal microleakage was found in the ormocer group (1.22 ± 0.01) followed by resin-modified glass ionomer cement group (1.31 ± 0.07) and the giomer group (1.78 ± 0.03). There was a highly statistically significant difference found between resin-modified glass ionomer cement group and the ormocer group, resin-modified glass ionomer cement group and giomer group. And no significant difference was found between the ormocer group and the giomer group.

CONCLUSION

The present study concluded that there was some amount of microleakage in primary teeth in all restorative materials examined in this in-vitro investigation. However, the marginal sealing ability of ormocer was found highest compared to resin-modified glass ionomer cement and Giomer materials.

CLINICAL SIGNIFICANCE

The primary reason dental restorations fail, particularly in Class V cavities, is microleakage since the margins of these restorations are typically found in the dentin or cementum. Assessing microleakage is a crucial step in determining the marginal integrity of restorative materials. Developing methods and resources that reduce the adverse effects caused by the restorative marginal seal failing would benefit from this. How to cite this article: Al Ghwainem A, Alqarni AS. Comparative Assessment of Marginal Micro Leakage of Different Esthetic Restorative Materials Used on Primary Teeth: An In-vitro Study. J Contemp Dent Pract 2024;25(1):58-61.

Clinical Evaluation of Low-shrinkage Bioactive Material Giomer Versus Nanohybrid Resin Composite Restorations: A Two-year Prospective Controlled Clinical Trial

This study evaluated the clinical performance of low-shrinkage bioactive resin composite compared with a conventional nanohybrid resin composite. A total of 35 patients (18 males, 17 females; mean age: 29±9 years old) received, randomly, 35 pairs of fillings restored with either low-shrinkage bioactive material employing Giomer filler technology (Beautifil II LS, Shofu Inc, Kyoto, Japan) or conventional nanohybrid resin composite (Clearfil Majesty Posterior, Kuraray, Japan) in Class I and Class II cavities. Two operators made all the restorations using the corresponding adhesive resins: FL-Bond II (Shofu Inc) and Clearfil SE Bond (Kuraray), according to each manufacturer's instructions. Two calibrated operators evaluated the restorations two weeks after placement (baseline), at six months, and at one and two years using FDI criteria (Scores 1-5). Data were analyzed using the McNemar test (α=0.05). Mean observation time was 27.4 ± 4.1 months (min=20.8; max=33.7). In both groups, according to FDI criteria, the restorations were mostly rated with best scores (Score 1 or 2) for biological, functional, and optical parameters. For one filling in the group restored with nanohybrid resin composite, a small and localized secondary caries lesion was observed and monitored at the one- and two-year follow-ups. One restoration in the low-shrinkage Giomer restorative group was accepted as a failure due to retention loss. Over the two-year follow-up, both the Giomer and the nanohybrid resin composite restorations' performance was clinically acceptable.

Comparative Evaluation of Microleakage of Bioactive, Ormocer, and Conventional GIC Restorative Materials in Primary Molars: An In Vitro Study Microleakage of Three Restorative Materials

This in vitro study aimed to evaluate and compare the microleakage of bioactive, ormocer, and conventional glass ionomer cement (GIC) restorative materials in primary molars. In this study, class V cavities were prepared on the buccal surface of 75 noncarious extracted primary molars. The teeth were then restored as per the groups assigned. Group A, group B, and group C used bioactive restorative materials, ormocer restorative materials, and conventional GIC restorative materials for restorations, respectively. The teeth were then thermocycled and subjected to microleakage analysis via dye penetration. The microleakage scores were compared for differences using the Kruskal–Wallis test. This was followed by multiple pairwise comparisons using the Dunn test. All testing was carried out using a ‘p’ value of <0.05. The percentage of samples showing microleakage score 0 depicting no dye penetration was highest for group A (56%) followed by group C (44%) and group B (12%). Statistical analysis revealed highest microleakage with group B, which was statistically significant ( $p$  < 0.05). Microleakage was evident in all the materials tested. The lowest microleakage was seen with bioactive restorative material.

Effect of fluoride recharge on the microleakage of fluoride-releasing restorative materials: An ex vivo confocal laser scanning microscopy study

Context:

Success or failure of a restoration depends on its ability to bond to the tooth structure, to reduce microleakage, and to inhibit secondary caries. Fluoride-releasing materials have the inherent potential to release fluoride and are also capable of recharging themselves with topical agents.

Aim:

The aim of this study was to compare and evaluate the effect of fluoride recharge on microleakage of different restorative materials.

Materials and Methods:

Eighty extracted teeth were collected and split mesiodistally into 160 specimens. Class V cavities were prepared on buccal and lingual surfaces. Specimens were divided into four groups of 40 each based on the restorative material. Group I: Glass ionomer; Group II: Resin composite; Group III: Giomer; and Group IV: Alkasite. The restored teeth were stored in artificial saliva. Each group was divided into four subgroups for fluoride recharge and subsequent confocal laser scanning microscopy (CLSM) examination: (A) no fluoride recharge and CLSM examination after 24 h, (B) no fluoride recharge and CLSM examination after 3 weeks, (C) fluoride recharge once at third week followed by CLSM examination at 6 weeks, and (D) fluoride recharge twice at third week and sixth week followed by CLSM examination at 9 weeks.

Statistical Analysis:

Kruskal−Wallis and Mann−Whitney U tests were performed to analyze the obtained data.

Results:

A significant difference in microleakage was noted among resin composite and other groups except Cention-N, whereas no significant difference was noted pre- and post-fluoride recharge.

Conclusion:

Increased microleakage was noted post-fluoride recharge, although statistically not significant.

Comparative Analysis of Microleakage of Zirconia-infused Glass Ionomer Cement with Miracle Mix and Amalgam: An In Vitro Study

Context

Various restorative materials are introduced in dentistry to achieve adequate strength and restore aesthetics. Dental amalgam is a versatile material with self-sealing property, but is unaesthetic. Other restorative materials like composites require conservative preparation, but exhibit polymerisation shrinkage resulting in microleakage. To overcome these drawbacks, a high strength restorative material reinforced with ceramic and zirconia fillers known as Zirconomer (Shofu Inc., Japan) has been introduced.

Aims

This in vitro study aims to evaluate and compare the microleakage of zirconia-infused glass ionomer cement (Zirconomer) with Miracle Mix (GC Fuji Miracle Mix, Japan) and amalgam.

Materials and methods

In this in vitro study, 30 non-carious premolar teeth were randomly divided into three groups (n=10) depending on the restorative material used—Silver Amalgam (DPI, India), Miracle Mix, and Zirconomer. Standard Class V cavities were prepared on the buccal surface of 30 non-carious extracted premolars. The restored teeth were thermocycled and then immersed in 2% methylene blue dye for 24 hours. All teeth were bisected longitudinally in a buccolingual direction and observed under a stereo microscope at 40X magnification for the evidence of dye penetration. The data were analyzed using one-way analysis of variance (ANOVA) and Kruskal-Walis tests (p<0.01).

Results

Zirconomer showed the least microleakage in Class V cavity restoration with a statistically significant difference to amalgam and Miracle Mix.

Conclusions

Zirconomer has proven to be an excellent restorative material as it showed the least microleakage followed by Miracle Mix and amalgam. Zirconomer raises the bar for restorative reinforced glass ionomers by outperforming conventional glass ionomers and amalgam restoration.

An In vitro Evaluation of Microleakage Associated with Three Different Compomer Placement Techniques in Primary Molars

Background:

Microleakage is one of the most frequently encountered problems in posterior tooth-colored restorations. Efforts to decrease this problem with resin restorations include techniques for reducing the ratio of bonded to unbonded restoration surfaces and following strategic incremental placement techniques to reduce residual stress at tooth-restoration interface which reduces the C-factor, hence microleakage.

Aim:

The present study aimed to evaluate microleakage associated with three placement techniques for compomer restorations in primary molars.

Design and Methodology:

This in vitro experimental study assessed the microleakage associated with bulk-fill, horizontal-incremental, and oblique-incremental compomer placement techniques in primary molars. Ninety specimens were divided into three groups of thirty for each of the placement techniques.

Results:

Nearly 86.6% of the specimens presented with microleakage involving the entire axial wall and pulpal floor in the bulk-fill group, whereas 56.6% and 46.6% of the specimens in the horizontal-incremental and oblique-incremental groups showed microleakage up to two-third and one-third of the axial walls, respectively. A significant difference in scores was observed between groups (P < 0.001).

Conclusion:

Microleakage was observed with all the three techniques but was comparatively lower with the incremental placement techniques. The oblique-incremental technique offered the least microleakage.

Composite Replacement of Amalgam Restoration Versus Freshly Cut Dentin: An In Vitro Microleakage Comparison

OBJECTIVE

The aim of this study was to evaluate the microleakage of the composite restorations when bonded to tooth structure previously restored with amalgam material compared with that of freshly cut dentin.

METHODS AND MATERIALS

Thirty intact, extracted intact human molars were mounted in autopolymerizing acrylic resin. Class II box preparations were prepared on the occluso-proximal surfaces of each tooth (4-mm bucco-lingual width and 2-mm mesio-distal depth) with the gingival cavosurface margin 1 mm above the CEJ. Each cavity was then restored using high copper amalgam restoration (Disperalloy, Dentsply) and then thermocycled for 10,000 thermal cycles. Twenty-five of the amalgam restorations were then carefully removed and replaced with Filtek Supreme Ultra Universal (3M ESPE); the remaining five were used for scanning electron microscopy and energy dispersive x-ray spectroscopy analysis. A preparation of the same dimensions was performed on the opposite surface of the tooth and restored with composite resin and thermocycled for 5000 thermal cycles. Twenty samples were randomly selected for dye penetration testing using silver nitrate staining to detect the microleakage. The specimens were analyzed with a stereomicroscope at a magnification of 20×. All of the measurements were done in micrometers; two readings were taken for each cavity at the occlusal and proximal margins. Two measurements were taken using a 0-3 scale and the percentage measurements.

RESULTS

Corrosion products were not detected in either group (fresh cut dentin and teeth previously restored with amalgam). No statistically significant difference was found between the microleakage of the two groups using a 0-3 scale at the occlusal margins (McNemar test, p=0.727) or proximal margins (Wilcoxon signed-rank test, p=0.174). No significance difference was found between the two groups using the percentage measurements and a Wilcoxon signed-rank test at either the occlusal (p=0.675) or proximal (p=0.513) margins. However, marginal microleakage was statistically significant between the proximal and occlusal margins (p<0.001).

CONCLUSION

Within the limitations of this in vitro study, no significant difference was found between the microleakage of nondiscolored dentin in teeth that were previously restored with amalgam compared with freshly cut dentin. However, marginal microleakage in the proximal surface was higher than that in the occlusal surface.