The impact of an alkasite restorative material on the pH of Streptococcus mutans biofilm and dentin remineralization: an in vitro study

Is Cention-N comparable to other direct dental restorative materials? A systematic review with network meta-analysis of in vitro studies

OBJECTIVES

To compare the performance of Cention-N® with direct restorative materials used at the daily practice (e.g., resin-based composites/RBC, glass ionomer cements/GIC, bioactive resins, silver amalgam) via a systematic review study.

METHODS

The review followed the PRISMA-NMA recommendations, and the protocol of the review was published at osf.io/ybde8. The search was conducted in PubMed/MEDLINE, Scopus, Web of Science, Embase, Lilacs, and SciELO databases, as well as in the grey literature (Open Grey, Proquest, and Periódicos CAPES). Studies with an in vitro experimental design evaluating the characteristics and properties of Cention-N in comparison to other restorative materials were included. The risk of bias of included studies was assessed using the RoBDEMAT tool, and meta-analyses were conducted using Review Manager 5.4 and MetaInsight V3 tools.

RESULTS

A total of 85 studies were included in the review, from which 79 were meta-analyzed. Several characteristics of direct restorative materials were analyzed, including physical (color change, degree of conversion, hardness, microleakage, polymerization rate, roughness, water solubility, water sorption), mechanical (bond strength to dentin, compressive strength, diametral tensile strength, flexural modulus, flexural strength, load-to-fracture, wear), and biological (alkalinizing effect, antibacterial activity, calcium and fluoride release) properties.

SIGNIFICANCE

Cention-N presented similar physico-mechanical properties compared to RBCs, but a stronger behavior than GICs. Despite the Alkasite nature of Cention-N, GICs may still demonstrate the greatest fluoride releasing ability from all direct restorative materials. This review confirmed the adequate behavior of Cention-N when compared to several other more traditionally used materials, confirming its applicability for the permanent restoration of decayed or fractured teeth.

Mechanical Properties of Alkasite Material with Different Curing Modes and Simulated Aging Conditions

This study aimed to evaluate the micro-mechanical and macro-mechanical properties of self-cured and light-cured alkasite and to investigate how accelerated degradation in acidic, alkaline, and ethanol solutions affects the macro-mechanical properties of self-cured and light-cured alkasite. The specimens of the alkasite material (Cention Forte, Ivoclar Vivadent) were prepared according to the following three curing modes: (1) light-cured immediately, (2) light-cured after a 5-min delay, and (3) self-cured. Microhardness was tested before and after immersion in absolute ethanol to indirectly determine crosslink density, while flexural strength and flexural modulus were measured using a three-point bending test after accelerated aging in the following solutions: (1) lactic acid solution (pH = 4.0), (2) NaOH solution (pH = 13.0), (3) phosphate-buffered saline solution (pH = 7.4), and (4) 75% ethanol solution. The data were statistically analyzed using a two-way ANOVA and Tukey post hoc test. The results showed that the microhardness, flexural strength, and flexural modulus were significantly lower in self-cured specimens compared to light-cured specimens. A 5-min delay between the extrusion of the material from the capsule and light curing had no significant effect on any of the measured properties. A significant effect of the accelerated aging solutions on macro-mechanical properties was observed, with ethanol and alkaline solutions having a particularly detrimental effect. In conclusion, light curing was preferable to self-curing, as it resulted in significantly better micro- and macro-mechanical properties, while a 5-min delay between mixing the capsule and light curing had no negative effects.

In vitro remineralization by various ion-releasing materials of artificially demineralized dentin: A micro-CT study

OBJECTIVE

The aim of this study was to evaluate the remineralizing properties of ion-releasing restorative materials on pH cycling-induced carious dentin.

METHODS

Fifty sound molars were freshly extracted. The occlusal surfaces were abraded using water-cooled sandpaper (800 grit). The residual crowns were embedded in self-cured acrylic resin with the flat dentin surface exposed. A mesio-distal trench was created using a calibrated 0.5 mm deep occlusal reduction burr, and artificial dentin caries were generated by pH cycling. Then, teeth were randomly assigned to five groups according to the ion-releasing material used. For each sample, micro-CT acquisitions were performed at various intervals. Remineralization was assessed by mean gray value (MGV) measurements after registration and segmentation of the region of interest with 3D Slicer software. One-way repeated-measures ANOVA followed by Tukey's post hoc test was used to investigate the difference in MGVs among the various groups.

RESULTS

Only Cention Forte showed significantly increased MGVs after 4 weeks compared to demineralized dentin. MGVs were higher, but not significantly, after placement of the restorative materials, including in the resin composite control group. These results can be explained by the radiopacity of the materials.

SIGNIFICANCE

Cention Forte, the material with the highest radiopacity, showed a significant increase in the MGVs of artificially carious dentin after 4 weeks. However, the study of dentin remineralization by micro-CT could be impacted by the radiopacity of the restorative materials used. The relevance of this examination for the study of dentinal remineralization should be investigated.

Initial bacterial adherence and biofilm formation on novel restorative materials used in paediatric dentistry

OBJECTIVE

To evaluate the initial bacterial adherence and biofilm formation on novel restorative materials in paediatric dentistry and compare the results to stainless steel crown and primary enamel.

MATERIALS AND METHODS

Twenty-five samples (Diameter = 4 mm) from five restorative materials (Tetric Power Fill light cured for 3 s or 10 s, Fuji II LC, Equia Forte HT Fil, Cention Forte, Stainless-steel crown) and primary enamel were prepared. Four samples served for recording of surface roughness (Ra) using a contact profilometer, 21 samples were incubated in stimulated human saliva for 2 h (initial bacterial adherence) and 72 h (biofilm formation) and served to determine ion releasing and bacterial growth. After 2 and 72 h, the number of colony-forming units (CFU) per ml was counted and expressed in Log10 CFU/ml. Data were analysed with two-way ANOVA and Tuckey's multiple comparisons test (p < 0.05).

RESULTS

All tested materials showed similar initial bacterial adherence (p > 0.1). Stainless steel crown showed statistically significantly less biofilm formation than all other tested materials (p ≤ 0.02), except for Fuji II LC (p = 0.06). In terms of biofilm formation, the differences between all tested materials were not statistically significant (p ≥ 0.9).

SIGNIFICANCE

Novel restorative materials in paediatric dentistry show similar initial bacterial adherence and biofilm formation. However, compared to other restorative materials, stainless steel crowns demonstrate the lowest level of biofilm formation. Ion-releasing materials may not necessarily show better antimicrobial properties than conventional materials.

Inhibition of Caries around Restoration by Ion-Releasing Restorative Materials: An In Vitro Optical Coherence Tomography and Micro-Computed Tomography Evaluation

The objective of this study was firstly to assess the demineralization inhibitory effect of ion-releasing restorations in enamel adjacent to restoration using a biofilm caries model and secondly to compare the effect to that in a chemical caries model. Fifty-six bovine incisors were filled with either Surefil one (SuO), Cention N (CN) (both ion-releasing materials), Ketac-Molar (GIC) or Powerfill resin composite (RC). The restored teeth were then randomly divided into 2 groups according to the used caries model (biofilm or chemical caries model). The micro-computed tomography (MicroCt) and optical coherence tomography (OCT) outcome measures used to evaluate demineralization inhibition effects were lesion depth, LD and increase in OCT integrated reflectivity, ΔIR, at five different depths. It was observed that all outcome measures of CN were statistically the same as those of GIC and conversely with those of RC. This was also the case for SuO except for LD, which was statistically the same as RC. When comparing the two caries models, LD of the biofilm model was statistically deeper (p < 0.05) than the chemical model for all four materials. In conclusion, CN and SuO have similar demineralization inhibitory effects as GIC, and the biofilm caries model is more discriminatory in differentiating demineralization inhibitory effects of ion-releasing restorative material.

Novel bioactive dental restorations to inhibit secondary caries in enamel and dentin under oral biofilms

OBJECTIVE

To provide the first review on cutting-edge research on the development of new bioactive restorations to inhibit secondary caries in enamel and dentin under biofilms. State-of-the-art bioactive and therapeutic materials design, structure-property relationships, performance and efficacies in oral biofilm models.

DATA, SOURCES AND STUDY SELECTION

Researches on development and assessment new secondary caries inhibition restorations via in vitro and in vivo biofilm-based secondary caries models were included. The search of articles was carried out in Web of Science, PubMed, Medline and Scopus.

CONCLUSIONS

Based on the found articles, novel bioactive materials are divided into different categories according to their remineralization and antibacterial biofunctions. In vitro and in vivo biofilm-based secondary caries models are effective way of evaluating the materials efficacies. However, new intelligent and pH-responsive materials were still urgent need. And the materials evaluation should be performed via more clinical relevant biofilm-based secondary caries models.

CLINICAL SIGNIFICANCE

Secondary caries is a primary reason for dental restoration failures. Biofilms produce acids, causing demineralization and secondary caries. To inhibit dental caries and improve the health and quality of life for millions of people, it is necessary to summarize the present state of technologies and new advances in dental biomaterials for preventing secondary caries and protecting tooth structures against oral biofilm attacks. In addition, suggestions for future studies are provided.