The effect of repeated fluoride recharge and storage media on bond durability of fluoride rechargeable Giomer bonding agent

Effect of a demineralization model on the microhardness, surface roughness and topography of giomers: An in vitro study

The purpose of this study is to compare the effect of a demineralization model on the microhardness, surface roughness, and topography of giomers.Seventy-two discs of six different dental materials in three different presentations (pit and fissure sealant (PFS), flowable and restorative materials) were divided into six groups (n = 12 p/g). Three experimental groups (giomers) consisted of BeautiSealant, Beautifil Flow Plus, and Beautifil II, and three control groups (resin-based materials) were formed using ClinproTM, FiltekTM Z350 XT Flow, and Filtek™ Bulk Fill materials. Vickers microhardness, surface roughness, and topographic analysis with atomic force microscopy were measured at the beginning (0) after four (1) and 7 days (2) of immersion in a demineralizing model. Statistical analysis was performed using One-way and Repeated Measures ANOVA and Pearson's correlation coefficient (p ≤ .05). The microhardness values showed significant variations, except for the G_RM group. All the groups presented significant increases in roughness through the experiment stages, except for RB_PFS in the Ra parameter. The topographic analysis showed variations in the micromorphology, especially in the experimental group at the end of the demineralization model. Finally, there was no correlation between microhardness and surface roughness. The demineralization model decreased the microhardness, with the lowest reductions in the giomers groups. The effect of the demineralizing model on the surface roughness and topography showed an increase in specific patterns for the experimental and control groups. Therefore, their clinical use is recommended. RESEARCH HIGHLIGHTS: The demineralization model decreased the microhardness property of the evaluated materials, with better performance for the giomer groups. The effect of the demineralizing model on surface roughness showed an increase with specific patterns for the experimental and control groups. Although the materials presented changes in their microhardness, roughness, and topography, their clinical use is recommended.

Comparison of the shear bond strength in Giomer and resin-modified glass ionomer in class V lesions

Introduction

There are several cosmetic, restorative materials to restore non-carious Cervical Lesions (NCCLs). The aim of this study was to specify and compare the shear bond strength of Giomer and resin-modified glass ionomer in Class V lesions so that whether Giomer showed a better shear bond strength, it could be used instead of RMGI to restore NCCLs because of its better esthetic.

Method

ology: 20 maxillary and 20 mandibular intact premolars were collected. Each group of 20 samples was divided into two 10-tooth subgroups of A and B. A class V preparation was made on the buccal surface of the samples with 2*2*3 mm dimensions using a diamond bur. Also, the crossing path of the universal machine chisel was prepped with 2 mm depth up to incisal edge. For group A, after applying BeautiBond and curing it, Beautifil II Giomer was placed in nylon cylinders and the cylinders were placed in the middle cervical region and cured for 20 s. For group B, 1 spoon powder of Fuji II RMGI was mixed with two drops of its liquid and transported to nylon cylinders and placed in the middle cervical region, then cured for 20 s. The nylon cylinders were removed from all 40 samples. Then, all teeth were thermocycled and then tested using a universal machine with the force of 20 MPa and the speed of 1 mm/min until they fractured to assess their shear bond strength. The obtained data was analyzed using SPSS v.26. The significance level was considered 0.05.

Results

There was no significant difference between Giomer (4.97 ± 2.36) and the resin-modified glass ionomer (3.41 ± 2.71) groups as regards their shear strength (p = 0.059). Likewise, there was no significant difference in shear bond strength between Giomer and RMGI groups as regards jaw type (P = 0.326).

Conclusion

The paper suggests that Giomer and resin-modified glass ionomer groups did not differ significantly in terms of their shear bond strength and that both can be utilized to treat Class V lesions. Furthermore, there was no significant difference between the shear bond strength in terms of jaw type.

Giomers in dentistry - at the boundary between dental composites and glass-ionomers

Introduction

From the variety of direct restorative dental materials, composite resins are considered as having the most esthetic and functional properties. The conservative preparation, esthetic results, good mechanical qualities and surface finishing properties of dental composites, combined with the protective properties of fluoride from glass-ionomers, led to a new generation of dental materials: the giomers.

Objective

The purpose is to review the available literature about the giomers, regarding the chemical composition, handling properties and esthetics, adhesion and microleakage, fluoride releasing and protection offered, clinical indications.

Method

The search was carried out using ScienceDirect and PubMed databases with the following keywords: giomer, esthetic properties giomers and fluoride releasing giomers. A total of 232 articles were initially selected, with the following inclusion criteria: full text articles, written in English, with topics on the properties and the clinical implications of giomers. Papers presented as abstract were not included. In the next step, review articles, duplicates, and articles in other languages were removed; as a result, a total of 44 sources published between 2004 and 2017 were selected.

Results

The selected articles referred to the following aspects about the giomers: chemical composition (8 articles), adhesion and microleakage (10 articles), fluoride releasing and pulp protection (15 articles), clinical indications (6 articles), effects of additional treatments and dietary habits (11 articles).

Spectrophotometric evaluation of white spot lesion treatment using novel resin infiltration material (ICON®)

Aims and Objectives

The aim of this study is to compare the esthetic improvement of white spot lesions (WSLs) treated by icon, sodium fluoride (NaF), and bioactive glass using VITA Easyshade^® spectrophotometer.

Methodology

Ninety intact human maxillary central incisors were collected and artificial WSLs were created on facial surface having dimensions of 4 mm × 4 mm by immersing in demineralized solution for 4 days, baseline comparisons were performed by measuring the color of the WSLs compared to the adjacent sound enamel. All samples were divided into three groups of 30 each. Three groups were Group 1: Treated by NaF, Group 2: Treated by the bioactive glass, and Group 3: ICON^®-DMG America (Resin infiltration). After treatment, the specimens of all groups were stored in artificial saliva and reevaluated at 4 and 8 weeks after the beginning of the treatments with VITA Easyshade^® spectrophotometer.

Results

Statistical analysis was performed with One-way analysis of variance. Post hoc analysis with the Tukey's honest significant difference test was used to compare the data between the groups. Among three groups, resin infiltration has significant color change (ΔE) of infiltrated lesions when compared to other treatment groups (P < 0.001).

Conclusion

Within the limitations of this study, it can be concluded resin infiltration (ICON^®) can improve the esthetic characteristics of WSLs. Resin (ICON^®) is a better treatment option when compared to bioactive glass and NaF as concerned to esthetics.

A Deep Morphological Characterization and Comparison of Different Dental Restorative Materials

Giomer is a relatively new class of restorative material with aesthetics, handling and physical properties of composite resins, and benefits of glass ionomers: high radiopacity, antiplaque effect, fluoride release, and recharge. To verify the superior properties of Giomers, in this study, a deep morphological characterization has been performed with an in vitro comparative study among a Giomer (Beautifil® II by Shofu Dental Corporation, Osaka, Japan), a Compomer (Dyract Extra by Dentsply, Caulk, Germany), glass ionomer cement (Ketac fil plus by 3M ESPE), and a composite resin (Tetric Evoceram by Ivoclar). In particular, mechanical and optical properties and ageing effects have been compared to investigate materials similarities and differences. Indentation tests, UV-Visible spectroscopy, Raman spectroscopy, and weight loss after storage in saliva or sugary drink have been carried out to analyze materials behavior in real conditions. The results confirm the high quality of Giomer material and indicate possible improvements in their usage.

Water Sorption, Solubility, and Color Stability of Giomer Restoratives

OBJECTIVES

This study compared the color stability, water sorption, and solubility of a giomer composite and two nanohybrid composite resins.

MATERIALS AND METHODS

Disc-shaped specimens (1-mm thickness × 15-mm diameter) of a giomer (Beautifil II, Shofu, Kyoto, Japan) and two nanohybrid (Filtek Z550, 3M ESPE, St. Paul, MN, USA; Tetric N-Ceram, Ivoclar Vivadent, Schaan, Liechtenstein) composites (N = 10) were prepared. Baseline color measurements were taken, and specimens were immersed in water for 28 days. Following immersion, color values were remeasured, and color-change values (ΔE) were calculated. Water sorption and solubility were assessed by mass gain or loss after storage in water for 28 days. Data were analyzed with one-way analysis of variance and Tukey's post-hoc tests (p = 0.05). Pearson's correlation test was used to assess possible correlations between water sorption and solubility, water sorption and color stability, and solubility and color stability (p = 0.05).

RESULTS

Water sorbtion (%) and color change (ΔE) varied significantly among groups, with Beautifil II exhibiting the highest values (p < 0.001). No statistically significant differences were observed in water solubility values among the groups (p = 0.661); however, a linear, positive correlation was detected between solubility and discoloration (r = 0.368, p = 0.046).

CONCLUSION

Water sorption and discoloration values of the giomer composite group were significantly higher than those of the nanohybrids tested.

CLINICAL SIGNIFICANCE

The high levels of water sorption and discoloration of giomer composites are likely to have an adverse effect on esthetic restorations.