Evaluation of Marginal Adaptation and Microleakage of Three Glass Ionomer-Based Class V Restorations: In Vitro Study

Effect of Cervical Margin Relocation With Different Injectable Restorative Materials on Fracture Resistance of Molars Received MOD CAD/CAM Onlay Restorations

OBJECTIVE

To investigate the effect of cervical margin relocation with four different injectable restorative materials on the fracture resistance of molars receiving mesio-occluso-distal CAD/CAM nanoceramic onlay restorations.

MATERIALS AND METHODS

One hundred and five sound mandibular molars received a standardized mesio-occluso-distal onlay preparation, with cervical margins located 2 mm apical to the cemento-enamel junction. The molars were randomly allocated into five groups (n = 21) according to the cervical relocating materials used: Group I had no cervical margin relocation; Group II used a highly viscous glass ionomer; Group III used a highly-filled injectable resin composite; Group IV used a resin-modified glass ionomer; and Group V used a bioactive ionic resin. All groups received immediate dentin sealing before nanoceramic resin-based CAD/CAM onlay restorations. After the specimens were subjected to thermo-mechanical loading, they underwent fracture resistance testing and failure mode analysis.

RESULTS

No statistically significant difference in fracture resistance was observed among the tested groups. Regarding the mode of failure, irreparable failure was significantly dominant, with no significant difference among the groups.

CONCLUSION

Employing injectable restorative materials for cervical margin relocation had no detrimental effect on the fracture resistance of molars receiving nanoceramic resin-based CAD/CAM onlay restorations.

CLINICAL SIGNIFICANCE

CAD/CAM onlay restorations preceded by cervical margin relocation using injectable restorative materials could tolerate compressive loading comparably to those without cervical margin relocation.

Ion-releasing resin composites prevent demineralization around restorations in an in-vitro biofilm model

OBJECTIVE

This study aimed to evaluate the effectiveness of two ion-releasing, resin-based composites (RBCs), ACTIVA BioACTIVE-Restorative (BIO1) and ACTIVA Presto (BIO2), in preventing demineralization around restorations.

METHODS

Class I and II cavities were prepared on bovine (n = 4) and human teeth (n = 8) and restored with BIO1, BIO2, a conventional composite (RBC, Filtek Supreme XTE), and a resin-modified glass ionomer cement (RMGIC, Ionolux). Following restorations (class I, n= 16/material; class II, n= 8/material), the specimens were exposed to Streptococcus mutans biofilm in a continuous-flow bioreactor over two weeks. Micro-computed tomography (micro-CT) assessed demineralization depths at restoration margins, and supernatant pH changes were measured after a 24-h acidic challenge. Statistical analyses included one and two-way ANOVA and Tukey's test (p < 0.05).

RESULTS

On enamel surfaces, RMGIC showed no demineralization, followed by BIO1 (≈50 μm), BIO2 (≈125 μm), and RBC (≈150 μm). No difference between human or bovine enamel was observed. In dentin, RMGIC showed the least demineralization (≈190 μm), followed by BIO1 (≈230 μm), BIO2 (≈280 μm), and RBC (≈400 μm). pH buffering was highest in RMGIC (+ 0.24 pH), while BIO1, BIO2, and RBC showed similar buffering capacities (∼ +0.1 pH). Gaps were found at several interfaces for BIO1 and RMGIC.

CONCLUSIONS

Ion-releasing RBCs varied in effectiveness for reducing demineralization of surrounding tissues, with limited pH buffering capacity. RMGIC exhibited better performance. Gaps between cavity walls and BIO1/RMGIC raised concerns about long-term adhesion.

CLINICAL SIGNIFICANCE

ACTIVA BioACTIVE Restorative (BIO1) and ACTIVA Presto (BIO2) resin-based composites promoted slight inhibition of demineralization in an in-vitro biofilm model, suggesting that further modifications in their chemical composition are necessary.

Does different application modes of universal adhesives with universal resin composites affect the microleakage in class V cavities? An in vitro study

AIM

Composite restorations often have gingival margins near the cemento-enamel junction (CEJ), where the microleakage of these margins can significantly contribute to the restoration failure, especially in the cervical lesions. It is important to determine the microleakage is crucial, as it typically occurs through the interfacial gap between the tooth and the restoration. Various resin composites and techniques have been developed to minimize this gap and reduce the risk of microleakage. The aim of this in vitro study was to evaluate the levels of microleakage of different modes of a universal adhesive and two novel resin composites in restoring class V cavities in the central incisors.

METHODS

Sixty-six freshly extracted sound human central incisors of the similar size were randomly assigned to 2 groups (n = 33 per group) according to the brand of resin composite. Each group was further divided into 3 subgroups based on the Scotch Bond Universal (3 M ESPE, Saint Paul, MN, USA) application protocol used: (a) total etch, (b) self-etch and (c) selective etch. After composite restoration completed with Omnichroma (Tokuyama Dental Corp., Tokyo, Japan) and Filtek Universal Restorative (3 M ESPE, Saint Paul, MN, USA), each tooth was immersed in a 0.5% basic fuchsin dye solution at 37C0 for 24 h. After dye penetration, teeth were sectioned and evaluated with conventional (scoring) and digital methods (ImageJ). The intra- and inter-examiner agreement was estimated according to the Kappa statistics and the results were analyzed with the one-way ANNOVA and the Kruskal-Wallis test (p < 0.05).

RESULTS

The rates of microleakage of the gingival and incisal margins are statistically similar, regardless of the composite brand and the method of application of the universal adhesive.

CONCLUSION

The microleakage exhibited by current adhesives and resins is independent of the adhesive application mode and measurement method.

Elemental analysis and micromorphological patterns of tooth/restoration interface of three ion-releasing class V restorations

OBJECTIVES

To evaluate and compare the ion-releasing capability of three different restorative systems at the restoration/tooth interface elemental analysis using energy-dispersive X-ray technique. Additionally, micromorphological patterns of the restoration/tooth interfaces was investigated.

MATERIALS AND METHODS

Eighteen freshly extracted sound human premolars were collected for the study. The premolars were randomly assigned into 3 groups (n = 6) based on the type of restorative materials used: Giomer (Beautifill II), ion-releasing composite (Activa Presto), and RMGI (Riva Light Cure). Half of the specimens in each group were tested after 24 h (the "immediate group"), while the remaining half were tested after 6 months of storage in deionized water (the "delayed group"). Standardized box-shaped cavities along the cervical area of teeth crowns and restored them with the assigned restorative material following manufacturers' instructions. The specimens were sectioned buccolingually into 2 halves. One half of each specimen was subjected to elemental analysis using energy-dispersive X-ray technique (EDX), while the remaining half was sputter coated and underwent micromorphological analysis of the restoration/tooth interface using a scanning electron microscope (SEM). The collected data from elemental analysis test were tabulated and subjected to statistical analysis.

RESULTS

The two-way ANOVA test showed significant differences in both phosphorus and calcium levels among the tested restorative systems (p < 0.05). In the immediate subgroup, RMGI recorded the highest phosphorus level (0.1527), followed by the ion-releasing composite (0.1172), while Giomer exhibited the least levels (0.0326) (p < 0.05). The ion-releasing composite group had the highest calcium level (0.2797), followed by RMGI (0.248), and Giomer (0.2385) respectively (p < 0.05). In the delayed subgroups, Giomer recorded the highest phosphorus level (0.1526), followed by the ion-releasing composite (0.1058), and RMGI group (0.0466) respectively (p < 0.05). RMGI had the highest calcium level (0.2801), followed by the ion-releasing composite (0.2659), and Giomer had the lowest level (0.1792) (p < 0.05). The micromorphological analysis of the restoration/tooth interfaces showed good adaptation between the composite and tooth substrate in different restorative groups.

CONCLUSIONS

The ion-releasing capability of the three restorative systems appears to be comparable. The rate of mineral release and diffusion is affected by time and composition.

Evaluation of surface microhardness and gingival marginal adaptation of three different bulk-fill flowable resin composites: A comparative study

OBJECTIVES

To evaluate surface microhardness and gingival marginal adaptation of three different bulk-fill flowable resin composites (FB-RBCs) in Class V cavities with enamel or dentin margins before and after thermocycling (TMC).

MATERIALS AND METHODS

Three available FB-RBCs were used; Palfique Bulk Flow (PaBF) (Tokuyama Dental), SDR Flow+ Bulk Fill Flowable (Dentsply Sirona), and I-Flow Bulk Fill (I-Dental). Thirty discs were prepared from each type of FB-RBCs. The discs were subjected to Vickers microhardness tester machine. Class V cavities were prepared on 180 molars. Gingival margins of half the specimens were prepared above CEJ and the other half below CEJ. Cavities were restored with FB-RBCs for gingival marginal adaptation test. Two-way ANOVA was used in microhardness, while three-way ANOVA was used for marginal adaptation.

RESULTS

The used materials showed statistically significant differences in microhardness and marginal adaptation.

CONCLUSIONS

Regarding microhardness, PaBF showed the highest value before TMC and SDR was the highest after TMC. Regarding marginal adaptation, SDR revealed the best marginal adaptation than PaBF and I-flow, either subjected to TMC or not.

CLINICAL SIGNIFICANCE

The longevity of cervical restorations depend on both the location of the cavity margin and the material used. The microfractures in resin composite surface due to low surface microhardness as well as marginal gaps seen in laboratory studies could be considered as an indicative parameter for clinical problem associated with marginal differences.

Microhardness and elemental analysis of ion-releasing restoration/ dentin interface following enzymatic chemomechanical caries excavation

BACKGROUND

This study was conducted to compare chemical, elemental and surface properties of sound and carious dentin after application of two restorative materials resin-modified glassionomer claimed to be bioactive and glass hybrid restorative material after enzymatic chemomechanical caries removal (CMCR) agent.

METHODS

Forty carious and twenty non-carious human permanent molars were used. Molars were randomly distributed into three main groups: Group 1 (negative control) - sound molars, Group 2 (positive control) - molars were left without caries removal and Group 3 (Test Group) caries excavated with enzymatic based CMCR agent. After caries excavation and restoration application, all specimens were prepared Vickers microhardness test (VHN), for elemental analysis using Energy Dispersive Xray (EDX) mapping and finally chemical analysis using Micro-Raman microscopy.

RESULTS

Vickers microhardness values of dentin with the claimed bioactive GIC specimens was statistically higher than with glass hybrid GIC specimens. EDX analysis at the junction estimated: Calcium and Phosphorus of the glass hybrid GIC showed insignificantly higher mean valued than that of the bioactive GIC. Silica and Aluminum mean values at the junction were significantly higher with bioactive GIC specimens than glass hybrid GIC specimen. Micro-raman spectroscopy revealed that bioactive GIC specimens showed higher frequencies of v 1 PO 4, which indicated high level of remineralization.

CONCLUSIONS

It was concluded that ion-releasing bioactive resin-based restorative material had increased the microhardness and remineralization rate of carries affected and sound dentin. In addition, enzymatic caries excavation with papain-based CMCR agent has no adverse effect on dentin substrate.

Two-year clinical and radiographic evaluation of ACTIVA BioACTIVE versus Compomer (Dyract® eXtra) in the restoration of class-2 cavities of primary molars: a non-inferior split-mouth randomised clinical trial

OBJECTIVES

The trial aimed to compare the clinical performance and radiographic success of ACTIVA BioACTIVE versus Compomer in restoring class-II cavities of primary molars.

MATERIALS AND METHODS

A non-inferior split-mouth design was considered. A pre-calculated sample size of 96 molars (48 per group) with class-2 cavities of twenty-one children whose ages ranged from 5 to 10 years were randomly included in the trial. Pre-operative Plaque Index (PI), DMFT/dmft scores and the time required to fill the cavity were recorded. Over 24 months, the teeth were clinically evaluated every six months and radiographically every 12 months by two calibrated and blinded evaluators using the United States public health service (USPHS)-Ryge criteria. The two-sided 95% confidence interval (CI) for the difference in success rate was considered to assess non-inferiority, and the margin was set at -18%. The linear mixed model and Firth's logistic regression model were used for data analysis (P < 0.05).

RESULTS

After 24 months, 86 teeth (43 per group) were evaluated. The mean PI score was 1.1(± 0.9), while DMFT/dmft was 0.35 (± 0.74) and 6.55 (± 2.25) respectively. The clinical and radiographic success rate of Dyract vs. ACTIVA was 95.3% and 88.3% vs. 93% and 86%, respectively. The two-sided 95% CI for the difference in success rate (-2.3%) was - 3.2 to 1.3% and didn't reach the predetermined margin of -18% which had been anticipated as the non-inferiority margin. Clinically, ACTIVA had a significantly better colour match (P = 0.002) but worse marginal discolouration (P = 0.0143). There were no significant differences regarding other clinical or radiographic criteria (P > 0.05). ACTIVA took significantly less placement time than Dyract, with a mean difference of 2.37 (± 0.63) minutes (P < 0.001).

CONCLUSION

The performance of ACTIVA was not inferior to Dyract and both materials had a comparable high clinical and radiographic performance in children with high-caries experience. ACTIVA had a significantly better colour match but more marginal discolouration. It took significantly less time to be placed in the oral cavity.

TRIAL REGISTRATION

The study was registered at ClinicalTrials.gov on 4 May 2018 (#NCT03516838).

Comparison of Reverse Sandwich Restorations Versus Composite Fillings for the Restoration of External Cervical Resorptions: An In-Vitro Study

OBJECTIVE

The aim was to compare the 'reverse sandwich restoration' to resin composite restorations re- garding marginal adaptation, fracture resistance, favourable/unfavourable fractures in the management of external cervical resorption.

METHODS

Forty-eight extracted maxillary central incisors were selected and endodontically treated. Cervical regions of the labial root surfaces received simulated resorptive defects and were restored as three randomly allocated groups: Reverse Sandwich Restoration (resin composite + resin-modified glass ionomer) (RSR); resin composite restoration (COMP), and no restoration (NR). Each group was further divided into two subgroups (n=8 each): Thermomechanical Aging (TA) (equivalent to one year) and No Aging (NA). Marginal adaptation was scored by scanning electron microscopy. Fracture resistance was tested using a universal testing machine. Favourable versus unfavourable fractures were classified based on fracture extent.

RESULTS

TA decreased the marginal adaptation for both RSR and COMP. Mean fracture resistance per groups were: RSR-NA 1522.4+-94.9N, RSR-TA 939.6+-72.9N, COMP-NA 1197.6+-95.7N, COMP-TA 870.4+-86.3N, NR-NA 1057.1+-88.1N, and NR-TA 836.6+-81.9N, respectively. Fracture resistance was the highest for RSR- NA compared to all other groups (p<0.05). TA decreased the fracture resistance in all groups (p<0.05), there was no significant difference between RSR and COMP regarding fracture resistance and favourable/ unfavourable fractures (p>0.05).

CONCLUSION

RSR provided comparable results to resin composite fillings to restore artificial cervical defects pertaining to marginal adaptation, fracture resistance, and favourable versus unfavourable fractures. RSR is preferable due to its inherent biocompatibility to the periodontium. (EEJ-2023-04-050).

Evaluation of the Effect of Nanographene Oxide on Microleakage of Conventional and Resin-Modified Glass Ionomer

Objectives

One of the important features of the restorative materials is the ability to seal and prevent the microleakage. Glass ionomer cement (GIC) still exhibits some microleakage despite establishing a chemical bond to the tooth. The aim of this study was to evaluate the effect of nanographene oxide (nGO) on the microleakage of conventional (CGIC) and resin-modified glass ionomer cement (RMGIC).

Methods

Thirty intact extracted molars were used. Class V cavities were prepared on their buccal and lingual surfaces. The samples randomly divided into two main groups of CGIC and RMGIC; each of them was randomly subdivided into three subgroups, including the group without nGO (control), the group with 1% nGO, and the group with 2% nGO. After restoring the cavities, they were subjected to thermocycling (1,000 cycles at 5/55°C). Two percent basic fuchsin solution was used to perform the microleakage test, and then the sectioned samples were examined by a stereomicroscope 40x. Kruskal-Wallis test, Dunn's test, and Mann-Whitney U test were used to analyze the data (P < 0.05).

Results

Group CGIC + 1% nGO at the gingival margin and group RMGIC + 1% nGO at both gingival and occlusal margins had significantly less microleakage than their control groups (P=0.008, P=0.002, P=0.023, respectively). Also, in these two groups, there were no significant differences between the microleakage of the occlusal and gingival margins (P=0.132, P=0.511, respectively), while in all other groups, the gingival microleakage was significantly higher than that of occlusal microleakage.

Conclusions

The addition of 1% nGO significantly reduced the gingival microleakage of CGIC and the occlusal and the gingival microleakage of RMGIC, while the addition of 2% nGO did not cause a significant reduction in microleakage.

Evaluation of Bioactive Restorative Materials' Color Stability: Effect of Immersion Media and Thermocycling

OBJECTIVES

One of the most important aspects that determines the clinical lifetime of aesthetic restorations, is the color stability (CS) over the long term. This study aims to assess the effect of artificial aging and thermocycling in different staining solutions on the CS of bioactive restorative materials compared to conventional ones.

METHODS

The following four material groups were investigated: ACTIVA™ Bioactive (AB) (Pulpdent Corporation, Massachusetts, United States), Beautifil II (BF) (SHOFU Inc., Kyoto, Japan), Fuji II (FJ) (GC Corporation, Tokyo Japan), and Filtek™ Z350 XT (FT) (3M, Minnesota, United States). A total of 100 specimens were fabricated using an acrylic mold and then immersed in five staining solutions groups: coffee, black tea, Cola, mixed berry juice, and saline. Baseline shade (T0) was recorded using two spectro-photometer devices, VITA Easyshade® Advance (VITA Zahnfabrik, Baden-Wurttemberg, Germany) and Color-Eye® 7000A (X-Rite, Inc., Grand Rapids, Michigan, United States). Following this, the shade was recorded at 30 days (T1), three months (T2), and after 5000 thermocycles (5C-55C) (T3). CIE L*a*b* (International Commission on Illumination color space) data was used to calculate ΔE for each group.

RESULTS

All samples showed a significant color change (P<0.001) following one and three months of storage and after thermocycling. AB and BF showed the highest CS over time, whereas FT and FJ showed the least CS.

CONCLUSION

The CS of restorative materials is mostly determined by their type, followed by staining solution type and thermocycling. The most potent solutions were coffee, tea, and berry juice.

Microshear Bond Strength of Bioactive Materials to Dentin and Resin Composite

OBJECTIVES

 The aim of this study was to comparatively evaluate microshear bond strength (μSBS) of bioactive ionic resin composite and resin-modified glass ionomer liner (RMGI) to dentin and resin composite.

MATERIALS AND METHODS

 The enamel of 11 posterior molar teeth was removed to expose dentin and then placed in acrylic blocks. Each specimen received three microcylindrical Tygon tubes filled with bioactive ionic resin composite (Activa Bioactive base/liner (PULPDENT: , MA, USA)), RMGI (Riva light cure SDI LTD, Bayswater, Australia), and resin composite (Filtek Z350xt, MN, USA). Composite discs (n = 11) were fabricated from nanofilled resin composite (Filtek Z350xt) and then fixed in acrylic blocks. Each specimen received two microcylindrical Tygon tubes filled with Activa Bioactive base/liner and Riva RMGI. All specimens were mounted individually to universal testing machine for μSBS test. Failure modes were analyzed using stereomicroscope and scanning electron microscope.

RESULTS

 Filtek Z350xt nanofilled resin composite showed the highest μSBS values. No statistical significant difference was found between Activa Bioactive and Riva RMGI (p > 0.05).

CONCLUSION

 Bioactive ionic resin composite liner exhibited similar bond strength as RMGI to dentin and resin composite.

Comparison of Shear Bond Strength and Microleakage between Activa™ Bioactive Restorative™ and Bulk-Fill Composites-An In Vitro Study

Bioactive materials have emerged as a promising alternative to conventional restorative materials as part of more conservative dentistry. The aim of this study was to evaluate and compare the shear bond strength (SBS) and microleakage of a new bioactive restorative material, two bulk-fill restorative composites, and a conventional composite at 24 h, 4 weeks, and 8 weeks. Three hundred and sixty molars and premolars were divided into four groups: ACTIVA™ BioACTIVE Restorative™, Filtek™ Bulk-Fill Restorative Composite, Tetric^® N-Ceram Bulk-Fill Composite, and G-aenial^® Composite. The normality of the data was determined with the Kolmogorov-Smirnov test, then the two-way ANOVA and Fisher's test were used for analyzing SBS data, and the Kruskal-Wallis and DSCF tests were conducted to analyze the microleakage. In the SBS test, there were no statistically significant differences between materials (p = 0.587), and the relation between material and time (p = 0.467), time points showed statistically significant differences (p = 0.016). As for the microleakage, statistically significant differences were found for all three time periods (p < 0.05), showing the conventional composite to have the lowest microleakage, followed by the bioactive material, and lastly the two bulk-fill composites. In conclusion, the new bioactive material has similar evaluated properties to bulk-fill composites (bond strength) and conventional composites (bond strength and microleakage) and can be used as an alternative restorative material.

Marginal integrity of classical and bulk-fill composite restorations in permanent and primary molars

Bulk-fill composites enable timesaving and less technical-sensitive application of restorations. This study investigated and compared the marginal integrity of classical and bulk-fill composite restorations in primary and permanent molars before and after thermo-mechanical loading (TML). Two Class II cavities were prepared in each of 20 primary and 20 permanent molars. The molars were randomised in four groups for each molar type. Groups 1 and 5 were restored with a high-viscous bulk-fill composite (Tetric PowerFill), groups 2 and 6 were restored with a flowable bulk-fill composite (Tetric PowerFlow), groups 3 and 7 were restored with a high-viscous classical composite (Tetric Prime), and groups 4 and 8 were restored with a flowable classical composite (Tetric EvoFlow). In permanent molars, the flowable composites were covered with a 2-mm layer of high-viscous composite (groups 6 and 8). The restorations were subjected to TML in a custom-made chewing machine (5-50 °C, 2 min dwelling time, × 1000; 400 ,000 loading cycles, 1.7 Hz, 49 N), and quantitative marginal analysis was conducted using scanning electron microscopy. Marginal integrity of each restoration was calculated as a percentage of continuous margins before and after TML. The tested high-viscous bulk-fill restoration showed similarly high marginal integrity in primary and permanent molars as the classical restoration. The tested flowable bulk-fill restoration showed the lowest marginal integrity compared to all other restorations after TML. In contrast to flowable bulk-fill restorations, high-viscous bulk-fill restorations show similar marginal integrity as classical hybrid composite restorations after TML, in both primary and permanent molars.

In vitro marginal and internal adaptation of four different base materials used to elevate proximal dentin gingival margins

Background

There is still debate about the most appropriate restorative material category to relocate the proximal deep cervical margins, thus, this study aimed to compare the marginal and internal adaptation of four base materials used for deep margin elevation, and to evaluate each base material/overlying composite interface.

Material and Methods

Fifty six molars received class II cavities with dentin/cementum gingival margins. They were divided into four groups and their gingival margins were elevated using either; resin modified glass ionomer (RMGI), highly viscous conventional glass ionomer (HV-GIC), flowable bulk fill resin composite (Bulk Flow) and bioactive ionic resin (Activa). The rest of the cavities were completed with the same overlying composite. Half of each group was either; kept in sterile water for 1 week, or subjected to 18 months water storage and 15,000 thermal cycles. Base materials/gingival dentin interfaces were examined under a scanning electron microscope at different magnifications, and percentage of continuous margin (% CM) and maximum gap width (MGW) were analyzed, in addition to base materials/overlying composite interfaces evaluations. % CM values were statistically analyzed using Two-way analysis of variance, Tukey post hoc tests (at p<0.05) and Pearson’s correlation while MGW values were analyzed using Kruskal–Wallis, Mann–Whitney U tests and Spearmen correlation

Results

Both Bulk Flow and Activa had better marginal integrity than RMGI and HV-GIC. All base materials were adversely affected by aging. All base materials/overlying composite interfaces were continuous and age defying.

Conclusions

In terms of marginal integrity, Bulk Flow and Activa might be preferable for proximal dentin margin elevation under direct restoration compared to the other tested base materials.

Key words:Deep proximal margin, interface analysis, marginal quality, open sandwich technique.

Microleakage Evaluation of Expired and Non-expired Resin Composites and Bonding Agents: In Vitro Study

Aim:

Although the shelf life is a key property of dental composites and bonding agents, these materials may often be used in simple procedures after expiration. In this study, the microleakage of two year expired and non-expired dental composites (Filtek Ultimate Universal A2 Enamel, 3M ESPE, USA, and Tetric N Ceram A2, Ivoclar Vivadent, Schaan, Liechtenstein) and a universal bonding system (Single Bond Universal, 3M ESPE, USA) was examined.

Materials and Methods:

In 40 freshly extracted human molars, two standardized Class II cavities (buccolingual and mesiodistal width of 3 mm and 4 mm, respectively) were prepared (80 cavity preparations). The teeth were thermocycled in distilled water for 1000 cycles in a 5°C to 55°C water bath. Next, the teeth and their apical foramens were coated with water resistant nail varnish, except for 1 mm around the restoration–tooth interface, and retained in a 1% methylene blue solution. After 24 h, the specimens were cut into two halves and analyzed using a stereomicroscope. Scanning electron microscopy images of two samples of the groups were obtained.

Results:

The Kruskal–Wallis test indicated no significant differences between the groups ( P < .05). The occlusal median scores were not significant ( P = .99). Moreover, the gingival median scores were not significant ( P = .48). No difference was found between the occlusal and gingival values in any group ( P > .05).

Conclusion:

These findings indicated that two-year-expired dental composites and bonding agent, which were maintained under proper conditions, do not have any significant difference in terms of the microleakage.

Marginal microleakage and modified microtensile bond strength of Activa Bioactive, in comparison with conventional restorative materials

OBJECTIVES

This study aimed to assess the enamel and dentin marginal microleakage and dentin microtensile bond strength (μTBS) of ACTIVA BioACTIVE Restorative with and without a bonding agent compared with conventional restorative materials.

MATERIAL AND METHODS

For enamel and dentin microleakage, Class II boxes were prepared in the mesial (1 mm under the cementoenamel junction) and distal (1 mm above the cementoenamel junction) surfaces of 90 extracted human third molars. The teeth were randomly divided into five groups (n = 18): Group Z (G-Premio Bond + Filtek Z250 XT), Group X (G-Premio Bond + X-tra fil bulk-fill), Group AA (G-Premio Bond + Activa Bioactive restorative), Group A (Activa Bioactive restorative), and Group G (dentin conditioner + Fuji II LC Improve). The teeth were thermocycled, and their microleakage was quantified using the dye penetration test under a stereomicroscope. For dentin μTBS measurement, 12 specimens were fabricated in metal molds (1 × 1 × 12 mm³) for each group mentioned above, and a universal testing machine measured their μTBS. Data were analyzed using one-way analysis of variance (ANOVA), the Kruskal-Wallis test, and multiple comparisons tests.

RESULTS

Significant differences were noted among the groups in marginal microleakage and μTBS (p < .001). The highest mean microleakage scores at the enamel and dentin margins were noted in Group A, which had significant differences with other groups (p < .001). The highest μTBS was found in Group X, with significant differences with Group G and Group A (p < .05). The lowest µTBS was noted in Group A, with significant differences with Groups X, Group AA, and Group Z (p < .001).

CONCLUSIONS

Activa Bioactive without a bonding agent showed significantly lower µTBS to dentin, and higher microleakage at the enamel and dentin margins. Application of adhesive resin with Activa Bioactive provided a dentine bond strength and marginal seal comparable to other restorative materials.

Mechanical, antibacterial, biocompatible and microleakage evaluation of glass ionomer cement modified by nanohydroxyapatite/polyhexamethylene biguanide

This study aims to look for the best concentration of nanohydroxyapatite (NHA) and polyhexamethylene biguanide (PHMB) incorporated into glass ionomer cement (GIC) in accordance with ISO:9917-1 and evaluate its mechanical, antibacterial, biocompatible and microleakages properties. NHA was incorporated into Fuji Ⅱ GIC powder at 0-8.00 wt% concentration and specimens were prepared; the best concentration was sifted out according to ISO9917-1. Based on best NHA proportion, 0-0.80% PHMB was dispersed into powder and samples were respectively prepared. Mechanical properties include net setting time (ST), compressive strength (CS), microhardness (VNH), solubility and scanning electron microscopy (SEM) observation. Those met ISO standard were qualified to continue microleakage observation, antibacterial activity, and biocompatibility test. The results suggested that GIC/6%NHA/0.2% PHMB and GIC/6%NHA/0.4%PHMB showed great performances in mechanical, antibacterial, and microleakage improvements, and the cytotoxicity of modified GIC showed no statistical difference with pure GIC.

Microleakage of Direct Restorations-Comparisonbetween Bulk-Fill and Traditional Composite Resins:Systematic Review and Meta-Analysis

Since the bulk-fill composites were produced, there was a progressive diffusion of their use for direct conservative treatment in posterior teeth. Their chemical structure increases the depth of cure and decreases the polymerization contraction; in this manner, bulk-fill composites can be placed in 4 mm single layers and the treatment times are considerably reduced. However, aesthetic and mechanical properties and impact on microleakage of bulk-fill resins are still unclear.

This systematic review and meta-analysis aimed to assess the risk of microleakage of direct posterior restorations made of bulk-fill versus conventional composite resins.

Researches were performed on PubMed and Scopus databases. Eligible in vivo studies, published since 2006, were reviewed. Outcomes of marginal discoloration, marginal adaptation, and recurrent caries were considered to conduct the systematic review and meta-analysis. Secondary data were examined to implement additional analysis and assess the risk of bias.

Eight randomized clinical trials were analyzed, involving 778 direct restorations. The summary of RCTs led to significant but inconsistent results; the marginal discoloration and recurrent caries were found to be improved respectively by 5.1 and 1.4%, whereas the marginal adaptation was reduced of 6.5%. Secondary analyses revealed that follow-up periods, the adhesive system used and the class of carious lesions evaluated are confounding factors, and they result in a risk of bias across studies.

Bulk-fill composites are innovative materials for conservative dentistry and they can be used to reduce treatment steps and duration of operative times. There are insufficient data to explore the relationship between bulk-fill composites and microleakage and further investigations are needed.

Systematic Review on White Spot Lesions Treatments

The difference in refractive index between the healthy enamel and the demineralized area generates a lesion with a milky white opaque appearance, clearly distinguishable from the surrounding healthy enamel. The aim of this systematic review was to evaluate if the infiltration technique is the most efficient treatment to resolve a white spot lesion when compared with remineralization and microabrasion techniques. The Population/Intervention/Comparison/Outcome question investigated: “in enamel WS lesion, the infiltration treatment compared to remineralization or microabrasion treatments is more or less effective in the camouflage effect?.” The research was performed on electronic databases, including Ovid MEDLINE, PubMed, and web of science. The search was conducted up to April 1, 2020. The scientific search engines produced 324 results. Only 14 were screened after screening. Based on the articles analyzed in this systematic review, the resin infiltration technique seems to be the most effective and predictable treatment for the aesthetic resolution of WSLs.

Impact of riboflavin and curcumin mediated photodynamic therapy and Er,Cr:YSGG on microleakage of class V resin glass ionomer restorations in permanent molar teeth

PURPOSE

The present study aimed to evaluate the impact of PDT using curcumin and riboflavin as photosensitizers and Er,Cr:YSGG on microleakage in class V RMGIC restorations in permanent teeth.

MATERIALS AND METHODS

Eighty permanent molars were investigated and randomly divided into 4 groups: control group: resin-modified glass ionomer restoration with no treatment, R-PDT: PDT with riboflavin, Cu-PDT: PDT with curcumin (Cu) and, Er,Cr:YSGG: laser application. All the teeth in each group were restored with the help of RMGIC. The samples were dipped for 24 h in 0.5 % Fuchsine solution, and subsequently fixed in acrylic resin-based molds. Microleakage scores were estimated considering both cervical and occlusal boundaries. Intergroup comparisons were made at each margin, and intragroup comparisons made at the cervical and occlusal margins. The Shapiro Wilk test was used to check the normality of the values. Whereas, the analysis of data was conducted using SPSS version 25 via the Kruskal-Wallis and Wilcoxon tests. P < 0.05 was contemplated to be statistically important.

RESULTS

A high frequency (95%) of the enamel walls were not penetrated when subjected to treatment with R-PDT, followed by Cu-PDT and Er,Cr:YSGG. The highest amount of microleakage was observed (55%) Cu-PDT at the site of the cavity near the cementum. The least amount of microleakage was observed in the control group. A statistically significant difference in microleakage was noted at the cervical wall (p=0.015), while no significant difference was seen at the occlusal wall (p=0.789) between the groups. A significant difference was noted at the cervical wall between the control and R-PDT group (p=0.021) and Cu-PDT group (p=0.005), respectively. A significant difference in microleakage was observed when occlusal was compared with cervical walls within each group (p<0.05).

CONCLUSION

Photosensitizers using riboflavin and curcumin may reduce the microleakage within the enamel surface restored with RMGIC in class V lesions that may not interfere with bonding. However, extreme caution should be taken while considering riboflavin and curcumin for class V RMGIC restorations extending to cementum surface.

In vitro wear of (resin-coated) high-viscosity glass ionomer cements and glass hybrid restorative systems

OBJECTIVES

The aim of the present study was to investigate the volumetric abrasive wear of a high-viscosity glass ionomer cement (hvGIC; Equia Fil) and a glass hybrid restorative system (ghRS; Equia Forte), each being recommended as amalgam alternatives. Both materials were applied with or without their respective resinous coating, and were compared with a conventional GIC (Ketac Fil) and a hybrid composite resin (CR; G-ænial Posterior).

METHODS

78 standardized occlusal Class I cavities were restored with the various materials (n = 13 per group). Before and after chewing simulation (30,000 cycles at 40 N), each sample underwent optical scanning procedures (Omnicam). A comparison of the total wear using a fluorescence-aided identification technique (OraCheck) followed, and differences (α = 5%) between groups were compared by means of MANOVA.

RESULTS

Regarding the wear rates of hvGIC and ghRS, no differences could be observed (p > .050), and this was not affected by the resinous coating. All hvGIC and ghRS restorations showed significantly higher abrasive wear than CR (p < .001), while the conventional GIC displayed a significant underperformance compared with any other material (p < .001).

CONCLUSIONS

Resinous coating of hvGIC or ghRS does not appear to exert an effective long-term protection against advanced abrasive wear. Compared to the conventional GIC showing a considerable substance loss, both hvGIC and ghRS materials revealed an improved abrasion resistance, but clearly failed to meet the excellent values of the CR.

CLINICAL SIGNIFICANCE

Occlusal loading should be carefully considered when using hvGIC or ghRS as amalgam (or composite resin) alternatives for the restoration of posterior teeth.

Effect of Saliva Contamination on Microleakage of Open Sandwich Restorations

Objectives

The purpose of the present study was to evaluate the microleakage of conventional glass-ionomer, resin modified glass-ionomer and glass hybrid ionomer Class II open sandwich restorations with or without saliva contamination.

Materials and methods

Sixty extracted sound human molar teeth were used and 120 class II slot cavities were prepared in mesial and distal surfaces. The gingival margins were located 1 mm below the cementoenamel junction. All specimens were randomly divided in 4 groups (n=15): Group I: High-Viscous Glass Ionomer (Fuji IX GP) Group II: Resin Modified Glass Ionomer (Fuji II LC) Group III: Glass Hybrid Ionomer (Equia-fil Forte), Group IV: Composite Resin (G'aenial Posterior). In open sandwich restoration groups, glass ionomer materials were placed to gingival floor in 1 mm thickness and rest of the cavity was filled with resin composite. After the restorations in mesial surfaces had been performed, distal cavities were restored with the same protocol after saliva contamination. The specimens were thermo-cycled for 10000 cycles at 5⁰C to 55⁰C and immersed in methylene blue dye solution (% 0,5) for 24 hours. Then, they were sectioned vertically through the center of the restorations from mesial to distal surface with a water-cooled diamond saw with 1mm thickness. Subsequently, the dye penetration was evaluated with image analysis software. Data were statistically analyzed (p<0.05).

Results

There was a statistically significant difference between gingival microleakage scores in no contamination groups, between high-viscous glass ionomer, Fuji IX GP and other materials tested (p<0.05). In saliva contaminated groups, there was no statistically significant difference between gingival microleakage scores (p>0.05). Additionally, there was not a statistically significant difference between the no contamination and saliva contaminated groups regardless of dental materials tested (p>0.05).

Conclusion

Within the limitations of this study, in open sandwich restorations, saliva contamination did not show an adverse effect on microleakage irrespective of dental materials tested. Glass hybrid ionomers and resin modified glass ionomers showed lower microleakage scores in gingival margins compared to high-viscous glass ionomer material in no contamination groups.

In Vivo Biocompatibility, Mechanical, and Antibacterial Properties of Cements Modified with Propolis in Different Concentrations

Objectives  The focus of this triple-blind randomized study was to evaluate the mechanical properties, antibacterial effect, and in vivo biocompatibility of glass ionomer cements (GICs) modified with ethanolic extracts of propolis (EEP).

Materials and Methods  For biocompatibility tests, 135 male Wistar rats were used and divided into nine groups: Group C (control, polyethylene), Groups M, M10, M25, M50 (Meron; conventional, and modified with 10%, 25%, 50% EEP, respectively), Groups KC, KC10, KC25, KC50 (Ketac Cem; conventional, and modified with 10%, 25%, 50% EEP, respectively). The tissues were analyzed under an optical microscope for different cellular events in different time intervals. Shear bond strength test (SBST) on cementation of metal matrices ( n = 10, per group), adhesive remnant index (ARI) in bovine incisors ( n = 10, per group), and antibacterial properties by the agar diffusion test ( n = 15, per group) were analyzed.

Statistical Analysis  Data were analyzed by Kruskal–Wallis test followed by Dunn, and one-way analysis of variance test followed by Tukey’s test ( p < 0.5).

Results  Morphological evaluation demonstrated intense inflammatory infiltrate in Groups M10 and KC10 in the time intervals of 7 ( p = 0.001) and 15 ( p = 0.006) days. Multinucleated giant cells were shown to be more present in Group M1, with statistical difference from Control and KC50 Groups in the time interval of 7 days ( p = 0.033). The SBST showed no statistical significance among the groups ( p > 0.05). Antibacterial property showed a statistically significant difference between Meron and Meron 50%-EEP Groups, and between Ketac and Ketac 50%-EPP Groups ( p = 0.001).

Conclusions  The intensity of histological changes resulting from the cements was shown to be inversely proportional to the concentration of propolis added; Ketac 50%-EPP was the concentration that had the most favorable biocompatibility results. Addition of EEP to GIC did not negatively change the SBST and ARI. Antibacterial property demonstrated a concentration-dependent effect.