An in vitro evaluation of Icon resin infiltrant penetration into demineralized enamel lesions using an indirect staining technique with confocal laser scanning microscope analysis in dual fluorescence mode

Context

White spot lesion is the first clinical sign of a caries lesion and represents mineral loss from the enamel subsurface.

Aim

The aim of this study was to evaluate the penetration depth (PD) of Icon resin infiltrant into artificially demineralized enamel lesions using confocal laser scanning microscope (CLSM) analysis in dual fluorescence mode.

Settings and Designs

The design of the study was an in vitro study.

Materials and Methods

22 extracted human permanent maxillary central incisor teeth were collected, and enamel sections were obtained from the coronal middle third. All enamel specimens were exposed to demineralization and remineralization solutions for 14 days. On positive confirmation of enamel demineralization by scanning electron microscope analysis, 20 specimens were then subjected to Icon resin infiltration following manufacturer instructions. Specimens were processed with indirect staining technique using rhodamine B and sodium fluorescein dyes and examined under CLSM at ×10 magnification in dual fluorescence mode using ImageJ software to evaluate PD of resin infiltrant into demineralized enamel lesions.

Statistical Analysis Used

Obtained data were analyzed using an independent t-test. P ≤0.05 was considered statistically significant.

Results

The maximum depth of demineralized enamel lesion was 590 μm, and the mean depth was 290.78 ± 14.80 μm. The maximum depth of resin infiltrant penetration was 580 μm, and the mean depth was 279.08 ± 13.88 μm; P = 0.006. The percentage penetration of resin infiltrant was 95.99%.

Conclusion

Icon resin infiltrant was highly effective in its depth of penetration into demineralized enamel lesions. The use of indirect staining and CLSM analysis in dual fluorescence mode is more reliable and accurate technique to evaluate the PD of resin infiltrant.

Long term remineralizing effect of casein phosphopeptide amorphous calcium phosphate in white spot lesions: A systematic review and meta-analysis

BACKGROUND

White spot lesions (WSLs) appear as white, opaque areas on the teeth and are caused by a demineralization of the enamel.

OBJECTIVE

The purpose of this systematic review and meta-analysis was to determine whether casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) has beneficial effects on WSLs and provides remineralizing benefits that are superior to those of placebo or no treatment.

METHODS

Following a thorough analysis of the literature across major online sources, 103 papers - 54 of which underwent in-depth evaluation - were found. We used inclusion and exclusion criteria to choose research articles that were appropriate for our review.

RESULTS

10 papers met this review's requirements and were subsequently included. As compared to the controls, CPP-ACP demonstrated increased efficacy in treatment of WSLs in terms of remineralisation and other parameters which included microhardness tests and enamel surface roughness. The forest plots present the results of meta-analyses comparing the effect of CPP-ACP versus control/other agents on white spot lesions (WSLs). In terms of odds ratios (OR), CPP-ACP showed a small increase in the odds of WSLs compared to control/other agents. In-vitro studies showed no significant difference in relative risk (RR) between CPP-ACP and control/other agents. Randomized control trials indicated a small increase in the risk of WSLs with CPP-ACP treatment, but the overall effect was not statistically significant.

CONCLUSION

There was evidence to support the use of CPP-ACP over other agents for WSL prevention or treatment, but further research is needed to confirm these findings.

Surface roughness and microhardness of enamel white spot lesions treated with different treatment methods

Objective

To analyse the surface roughness and microhardness of artificial enamel white spot lesions before and after WSL formation, after treatment (Opalsutre™ microabrasion, Sylc® bioactive glass, and ICON® resin infiltration), and after pH cycling with the help of the profilometer surface roughness tester and the digital Vickers microhardness tester.

Materials and methods

Seventy-five extracted molars were used to acquire one hundred specimens. 50 specimens were randomly assigned to five groups (n = 10) for the surface roughness study: 1) Sound group, 2) WSL group, 3) micro abrasion (MA; Opalustre, Ultradent, South Jordan, UT, USA), 4) bioactive glass 45S5 Sylc powder (Sylc; Denfotex Research Ltd, Inverkeithing, UK), and 5) ICON resin infiltration (ICON; DMG, Hamburg, Germany). An additional 25 specimens were used to obtain 50 enamel slabs for the surface microhardness study, which were also assigned to the same groups. All groups underwent a final stage of pH cycling. Surface roughness and surface microhardness measurements were performed at different stages for all groups.

Results

Regarding surface roughness, ICON significantly reduced the surface roughness compared to Opalustre and Sylc, with no significant difference between Opalustre and Sylc. In terms of surface microhardness, ICON showed the highest improvement, followed by Sylc and then Opalustre. Both surface roughness and microhardness were significantly affected by demineralization, partially improved after treatment, and then regressed significantly after pH cycling.

Conclusion

ICON resin infiltrant can be considered as a superior treatment option for improving surface roughness and microhardness, while Opalustre demonstrated relatively the poorest performance compared to the other treatment options. It is noteworthy that the pH cycling procedure had an adverse impact irrespective of the treatment option used.

Application of laser on enamel surface with three types of bioactive glasses-based resin infiltrants: An in vitro study

OBJECTIVE

The study aimed to evaluate and compare the surface micro-hardness, roughness, color, and morphology of enamel after Er,Cr:YSGG laser irradiation, followed by application of three types of bioactive glasses-based resin infiltrants, and the samples groups were challenged with the pH cycle.

METHODOLOGY

Experimental photoactivated resin infiltrants were synthesized using dimethacrylate resins, whereby three different types of bioactive glasses (BGs), i.e., 45S5, fluoridated-BG (F-BG), and borosilicate-BG (B-BG), were incorporated into the resin system. Initially, white spot lesions were created artificially on the toosth enamel surface, then irradiated with Er,Cr:YSGG laser. Then, the resin-only and BG-based resins were infiltrated on the enamel surface. All samples were pH challenged for 14 days, and the micro-hardness, surface roughness, surface morphology, and color stability (ΔE) analyses were conducted before and after the 14 days pH challenge.

RESULTS

After laser irradiation, the micro-hardness was significantly high with 45S5 group compared to resin-only (p = 0.021), F-BG (p = 0.042), and B-BG (p = 0.001) groups. After the pH challenge, the micro-hardness values for all groups were reduced significantly (p ≤ 0.05). The surface roughness was least with the resin-only group and showed a non-significant difference with F-BG (p = 0.34) and significant differences with both B-BG (p = 0.005), and 45S5 (p = 0.010) groups. After the pH cycle, the roughness of all groups was increased significantly (p ≤ 0.05), except B-BG group showed a non-significant difference (p = 0.528). The B-BG group showed significantly high ΔE between day 0 and baseline compared to resin-only (p = 0.0008), F-BG (p = 0.017), and 45S5 (p = 0.029), whereas between day 14 and baseline, the lowest ΔE value was observed for B-BG (14.2 ± 2.10) and maximum for the resin-only (20.57 ± 2.47) group. The SEM images showed pitting on the surface of all resin infiltrant groups after 14 days of pH challenge.

CONCLUSION

The morphological difference was observed after the laser irradiation on the enamel surface. The differences in micro-hardness, surface roughness, and color were observed after the application of experimental resin infiltrants and significant differences were observed after the pH challenge.

Roughness and Microhardness of Demineralized Enamel Treated with Resinous Infiltrants and Subjected to an Acid Challenge: An in vitro Study

Background:

Resinous infiltrating has proven effective in arresting incipient caries lesions.

Objective:

This study aimed to assess the penetration depth of an experimental resin-infiltrant (75% - TEGDMA, 25% - Bis-EMA, 1% - EDAB, 0.5% camphorquinone), compare it with commercial infiltrant Icon®, and analyze the surface-roughness and microhardness of the resin-materials infiltrated into tooth specimens, before and after pH cycling.

Methods:

To assess penetration depth, sound third molar specimens were submitted to ten de-remineralization cycles for incipient carious lesion induction and were then randomly divided into 2 groups (n=3): (I) Experimental Infiltrant (EI) and (II) Commercial Infiltrant Icon (CI). After resin infiltration into specimens, qualitative Confocal Fluorescence Microscopy images were captured. For roughness and microhardness assessment, new specimens were demineralized, then randomly divided into two groups (n=20): (I) Experimental Infiltrant (EI) and (II) Commercial Infiltrant Icon (CI) and submitted to roughness and microhardness readouts at the following time-intervals: (T1) sound tooth, (T2) white-spot caries lesion, (T3) resin material that infiltrated, and (T4) resin material that infiltrated and was exposed to pH-cycling. In statistical analyses, generalized linear models of repeated measures in time were applied, with a significance level of 5%.

Results:

The experimental infiltrant penetrated the carious lesion and exhibited lower roughness values after its application, even after pH cycling, similar to the CI. The microhardness value of the EI group was significantly lower in the last three-time intervals evaluated compared to CI.

Conclusion:

Experimental resin infiltrant was efficient in penetrating white spot lesions and reducing surface roughness; however, it did not increase surface microhardness.

The effect of minimally invasive treatments on enamel microhardness and resistance to further demineralization

Objectives: The present study aimed to compare microhardness of inactive proximal lesions treated by resin infiltration, Er:YAG laser + resin infiltration and Bioactive glass, and investigate the resistance of treated lesions to further demineralization challenge. Methods: In this in-vitro study, 30 human molars with inactive proximal lesions were selected and randomly divided into three groups of 10. In group 1 (resin infiltration), the lesions were treated by a resin infiltrant (Icon). In group 2, the surface was conditioned by an Er:YAG laser prior to resin infiltration. The specimens in group 3 were remineralized by bioactive glass. The treated specimens were kept in artificial saliva for 1 week and then immersed in a demineralization solution for 8 weeks. Surface microhardness was measured at baseline (T0), after remineralization (T1) and after exposure to the demineralization solution (T2), and the difference in microhardness between time points (ΔVHN) was calculated. Results: Microhardness after demineralization (T2) was significantly lower than those of other intervals (P0.05). The statistical analysis revealed no significant difference either in ΔVHNT1-T0 or in ΔVHNT2-T1 among the study groups (P>0.05) Conclusion: Pretreatment by the Er:YAG laser prior to resin infiltration was more effective that other treatments in enhancing microhardness and protecting the tooth against acidic challenge. However, the difference between groups did not reach a statistical significance, implying the need for further studies to achieve more conclusive results.

Effect of different surface treatments on the microhardness and colour change of artificial enamel lesions

BACKGROUND

To investigate the effect of three different surface treatments on the microhardness and colour change of artificial enamel lesions.

MATERIALS AND METHODS

One hundred bovine teeth were randomly assigned into four groups. Artificial enamel lesions were created using demineralizing solution for all groups except the sound enamel group. Different surface treatments were then performed G1: resin-infiltrant; G2: Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP); G3: artificial saliva; G4: Sound Enamel. Each group was subdivided into three subgroups, where each subgroup was subjected to a different testing method. Subgroup 1: surface microhardness; subgroup 2: cross-sectional microhardness; subgroup 3: colour measurement. Statistical analysis was performed by ANOVA, followed by Tukey's post hoc test.

RESULTS

Sound enamel group recorded the highest surface and cross-sectional microhardness results. No significant difference was found between the resin-infiltrant group and CPP-ACP regarding surface and cross-sectional microhardness at different lesion depths. Resin-infiltrant group showed the least colour change (∆E) results compared to the other groups.

CONCLUSION

Resin-infiltrant can effectively enhance surface microhardness and enamel resistance to demineralization, additionally, reduces the staining susceptibility of white spot lesions (WSLs) after treatment. CPP-ACP application for 4 weeks seems to improve surface microhardness; however, has a limited effect in resisting staining of WSLs after treatment. © 2022 Australian Dental Association.

Casein phosphopeptide amorphous calcium phosphate and universal adhesive resin as a complementary approach for management of white spot lesions: an in-vitro study

Background

White spot lesion (WSL) is the most common consequence during and after orthodontic treatment. This study was conducted to investigate the ability of casein phosphopeptide amorphous calcium phosphate (CPP-ACP) coupled with universal adhesive resin to treat white spot lesions.

Material and methods

Forty-five extracted premolars were sectioned to create 90 specimens. Seventy-five specimens were demineralized to generate artificially created WSLs. Different strategies have been applied for the management of the artificially created WSLs. Six experimental groups were employed: Group I: sound enamel (control), Group II: demineralized enamel (artificially-created WSLs), Group III: ICON resin-treated WSLs, Group IV: CPP-ACP-treated WSLs, Group V: universal adhesive resin-treated WSLs, and Group VI: CPP-ACP followed by universal adhesive resin-treated WSLs. Assessment of color stability using a spectrophotometer, surface microhardness using a Vickers tester, and surface roughness using a profilometer was done. The surface topography of representative specimens from each experimental group was inspected using a scanning electron microscope. Collected data were analyzed using one-way ANOVA followed by Tukey’s post hoc test at p ≤ 0.05.

Results

White spot lesions treated with CPP-ACP and subsequently coated with universal adhesive resin (Group VI) exhibited a significantly lower ΔE than both CPP-ACP (Group IV) and universal adhesive resin-treated (Group V) groups (p ≤ 0.05), but it was not significantly different from the ICON resin-treated group (Group III). For surface microhardness, WSLs treated with CPP-ACP and consequently coated with universal adhesive resin (Group VI) recorded the highest mean that was significantly different from both ICON resin (Group III) and universal adhesive resin-treated (Group V) groups (p ≤ 0.05). All the tested strategies (ICON resin, CPP-ACP, universal adhesive resin, and CPP-ACP followed by universal adhesive resin) significantly lowered the surface roughness of the WSLs (p ≤ 0.05), while no significant difference was detected among them.

Conclusions

Combining a considerable caries remineralizing program using CPP-ACP with subsequent universal adhesive resin infiltration could be a promising approach to manage WSLs efficiently through increasing surface microhardness and restoring esthetic while developing a smoother surface.

In vitro effect of resin infiltrant on resistance of sound enamel surfaces in permanent teeth to demineralization

OBJECTIVE

To investigate the effect of resin infiltrant on resistance of sound permanent enamel surfaces to demineralization.

METHOD

Eighty healthy premolars were sectioned to obtain enamel blocks from the buccal surface. Specimens with baseline surface microhardness values of 320-370 were selected. The experimental group were treated with resin infiltrant, while the control group was not. Specimens from each group were artificially demineralized and the surface microhardness values were measured again. Confocal laser scanning microscopy was used to measure the depth of demineralization and detect the penetration ability of the resin infiltrant. The specimens were subjected to a simulated toothbrushing abrasion test. Scanning electron microscopy was used to observe changes in the surface morphology of specimens after each of these procedures.

RESULTS

No significant differences between the experimental and control groups were observed in the baseline microhardness values or in the experimental group after resin infiltration compared with the baseline conditions. After artificial demineralization, the microhardness value in the control group was significantly lower than that in the experimental group (266.0 (±34.5) compared with 304.0 (±13.0), P = 0.017). Confocal laser scanning microscopy results showed that the demineralization depth in the control group was significantly deeper than that in the experimental group (97.9 (±22.8) µm vs. 50.4 (±14.3) µm, P < 0.001), and that resin infiltrant completely penetrated the acid-etched demineralized area of the tooth enamel with a mean penetration depth of 31.6 (±9.0) µm. Scanning electron microscopy showed that the surface morphology was more uniform and smoother after simulated toothbrushing. The enamel surface structure was more severely destroyed in the control group after artificial demineralization compared with that of the experimental group.

CONCLUSION

Resin infiltrant can completely penetrate an acid-etched demineralized enamel area and improve resistance of sound enamel surfaces to demineralization. Our findings provide an experimental basis for preventive application of resin infiltrant to sound enamel surfaces to protect tooth enamel against demineralization.

Minimally Invasive Therapies for the Management of Dental Caries—A Literature Review

In recent years, due to a better understanding of the caries pathology and advances in dental materials, the utilization of non-invasive and minimally invasive techniques that delay/obviate the need for traditional restorations has started gaining momentum. This literature review focuses on some of these approaches, including fluoride varnish, silver diamine fluoride, resin sealants, resin infiltration, chemomechanical caries removal and atraumatic restorative treatment, in the context of their chemistries, indications for use, clinical efficacy, factors determining efficacy and limitations. Additionally, we discuss strategies currently being explored to enhance the antimicrobial properties of these treatment modalities to expand the scope of their application.

Novel nanostructured resin infiltrant containing calcium phosphate nanoparticles to prevent enamel white spot lesions

OBJECTIVES

The objective of this study was to develop a novel nanostructured resin infiltrant containing nanoparticles of amorphous calcium phosphate (NACP) to treat enamel white spot lesions (WSLs). Physical properties and the therapeutic effect of the new resin infiltrant were investigated for the first time.

METHODS

NACP was incorporated into ICON (Icon caries infiltrant, DMG, Germany) with different mass fractions. Cytotoxicity, degree of conversion, surface hardness, calcium (Ca) and phosphorus (P) ions release concentrations were tested. After application to the demineralized enamel samples, the color changes were determined. Surface and cross-sectional hardness were measured, scanning electron microscopy (SEM) images were taken on the cross-section of samples to observe microstructure changes after 14-day pH cycling.

RESULTS

Incorporating 10%-30% of NACP did not compromise the biocompatibility and physical properties of the resin infiltrant. ICON + 30% NACP group had long-lasting and high level of Ca and P ion release. After 14-day pH cycling, enamel surface hardness of ICON + 30% NACP group was 1.83 ± 0.21 GPa, significantly higher than the control group (1.32 ± 0.18 GPa) (p < 0.05). ICON + 30NACP group had the highest cross-sectional enamel hardness among all groups (p < 0.05), especially at 50 μm and 100 μm depth. SEM images showed that apparent enamel prism and inter-prism gaps in negative control were masked by mineral deposition in ICON + 30% NACP group.

SIGNIFICANCE

The novel ICON+30% NACP infiltrant is promising to inhibit enamel WSLs, protect the enamel and increase its hardness.

Effect of Resin Infiltration on Enamel: A Systematic Review and Meta-Analysis

Subsurface enamel demineralization beneath an intact surface layer or white spots lesions (WSL) can and should be treated with non-invasive procedures to impede the development of a cavitated lesion. We aim to analyze if infiltrative resin improves enamel roughness, microhardness, shear bond strength, and penetration depth. MEDLINE [via Pubmed], Cochrane Central Register of Controlled Trials, Embase, Web of Science, Scholar, and LILACS were searched until May 2021. Methodological quality was assessed using the Joanna Briggs Institute Clinical Appraisal Checklist for Experimental Studies. Pairwise ratio of means (ROM) meta-analyses were carried out to compare the enamel properties after treatment with infiltrative resin on sound enamel and WSLs. From a total of 1604 articles, 48 studies were included. Enamel surface roughness decreased 35% in sound enamel (95%CI: 0.49–0.85, I² = 98.2%) and 54% in WSLs (95%CI: 0.29–0.74, I² = 98.5%). Microhardness reduced 24% in sound enamel (95%CI: 0.73–0.80, I² = 99.1%) and increased by 68% in WSLs (95%CI: 1.51; 1.86, I² = 99.8%). Shear bond strength reduced of 25% in sound enamel (95%CI: 0.60; 0.95, I² = 96.9%) and increased by 89% in WSLs (95%CI: 1.28–2.79, I² = 99.8%). Penetration depth was 65.39% of the WSLs (95%CI: 56.11–74.66, I² = 100%). Infiltrative resins effectively promote evident changes in enamel properties in sound and WSLs. Future studies with long-term follow-ups are necessary to corroborate these results from experimental studies.

A comparative evaluation of penetration depth and surface microhardness of Resin Infiltrant, CPP-ACPF and Novamin on enamel demineralization after banding: an in vitro study

Background

The field of dentistry has been revolutionized by various concepts. Minimal invasive dentistry is the preferred treatment approach in the present era; therefore, various techniques have been advocated to arrest caries lesions at an early stage on the grounds of better understanding of the dynamic nature of dental caries. Thus, study was conducted to compare and evaluate the penetration depth and enamel microhardness of Resin Infiltrant, CPP-ACPF and Novamin on artificial demineralized enamel surface after orthodontic banding.

Material and methods

Eighty extracted sound premolars were banded. The bands were cemented with type 1 GIC and further divided into – Group I: Resin Infiltrant, Group II: CCP-ACPF, Group III: Novamin and Group IV: Control. The samples were incubated for 30 days and then thermocycled. A window of 4 mm × 4 mm was prepared on the buccal surface of samples and artificially demineralized for 4 weeks. A single application was made for Resin Infiltrant, while Novamin and CCP-ACPF were applied twice daily. These samples were otherwise immersed in artificial saliva, and this was protocol was observed for 14 days. For the evaluation of penetration depth, 10 samples from each group were bucco-lingually sectioned and immersed in methylene blue dye solution for 24 h and then evaluated under stereomicroscope. For the enamel surface microhardness, remaining 10 samples from each group were embedded in acrylic resin with outer buccal surface exposed and were tested by a using digital Micro-Vickers hardness tester.

Results

All groups showed a significant difference in the depth of dye penetration and surface microhardness compared to the control group. As compared to the other tested groups, Resin Infiltrant exhibited the highest significant reduction in demineralization and increased microhardness. Novamin had a deeper penetration and increase in microhardness as compared to CCP-ACPF.

Conclusion

Resin Infiltrant exhibited the highest potential to impede caries and constitutes a competent aerosol free micro-invasive strategy for combating non cavitated lesions approaching the outer layer dentine which are too advanced for remineralizing agents but do not necessarily require any drilling of tooth.

The Evaluation of Different Treatments of Incipient Caries Lesions: An in Situ Study of Progression Using Fluorescence-based Methods

CLINICAL RELEVANCE

Effective methods to control incipient caries lesions are needed. In this investigation, several methods provide encouraging results.

SUMMARY

This study aimed to evaluate in situ the inhibition of incipient caries lesion progression using different treatment protocols and to evaluate the effectiveness of fluorescence-based methods (DIAGNOdent, DIAGNOdent pen, and VistaProof fluorescence camera [FC]) in monitoring this process. The research was conducted in four phases: (1) at baseline, (2) after a first cariogenic challenge, (3) after treatment modalities, and (4) after a second cariogenic challenge. Sixteen volunteers used intraoral acrylic palatal appliances, each containing six enamel blocks (n=96). The cariogenic challenge was performed using a 20% sucrose solution over a 14-day period. The appliances were removed eight times a day and, upon removal, two drops of the solution were placed onto each enamel block. The enamel blocks were randomly assigned to three treatment groups: fluoride varnish ([FV] Duraphat; n=32), resin infiltrant ([RI] Icon; n=32), and adhesive system ([AS] Scotchbond; n=32). At the end of each phase, the surface microhardness (SMH) was measured, and two trained examiners evaluated the specimens using fluorescence-based methods. In addition, integrated mineral loss (ΔΔZ; vol%.min x μm) and lesion depth (ΔLD; μm) were evaluated using transverse microradiography. A two-way analysis of variance and a Tukey post hoc test were calculated (α=5%). Significant differences in SMH were observed according to the treatment, phases, and interaction of factors (p<0.001). Treatment with FV resulted in significantly higher SMH values in phases 3 and 4 compared to RI and AS, with the last two treatments resulting in similar values (p>0.05). The ΔΔZ value was similar for FV and AS but significantly higher for RI (p=0.016). ΔLD was not significantly different among the groups (p=0.126). Significant differences in the measurement of fluorescence for each fluorescence-based method were observed between each phase of the study (p<0.05). It can be concluded that all treatments were effective in inhibiting the in situ progression of incipient lesions, although to different degrees, with minor mineral loss changes observed for the AS and FV. Besides, all fluorescence-based methods tested, except for that using the FC device, were effective in monitoring caries lesion progression.

Experimental self-etching resin infiltrants on the treatment of simulated carious white spot lesions

OBJECTIVES

To evaluate the penetration depth (μm) of experimental resin infiltrants containing different percentages of triethylene glycol dimethacrylate (TEGDMA) and phosphoric acid 2-hydroxyethyl methacrylate ester (PAM) in artificial carious white spot lesions (WSL).

METHODS

WSL were produced in 65 bovine flat enamel specimens by pH cycling protocol, which were treated with either Icon (control) or experimental acidic infiltrants based on different percentages of TEGDMA and PAM monomers (acidic), and their association or not with previous acid-etching with phosphoric acid. Ten readings using Confocal Laser Scanning Microscopy were conducted on each specimen and the penetration depth was calculated from the surface until the deepest point with the fluorescent dye Rhodamine B (0.02 mg/mL). The pH and the viscosity of the experimental infiltrants were also tested. Data were statistically analyzed with two-way ANOVA and Tukey tests (α < 0.05).

RESULTS

The material factor and the interaction material*acid-etching were statistically significant. The lowest penetration depth was observed for the samples treated with the commercial infiltrant after etching with 15% hydrochloric acid. When specimens were pre-treated with PA, highest penetration was seen for specimens treated with 100% TEGDMA, which differed from all other groups. The lowest penetration was seen for those treated with 50:50 TEGDMA:PAM infiltrants. When specimens were not previously etched, highest penetration was seen for Icon, which differed only from those treated with 25% TEGDMA 75% PAM, where the lowest values were seen. The values of viscosity increased and the pH decreased with the addition of PAM in the infiltrant formulations.

CONCLUSION

the association between TEGDMA and PAM seems to allow similar infiltration depth reached by Icon infiltrant without acid etching the enamel surface.

Can composition and preheating improve infiltrant characteristics and penetrability in demineralized enamel?

The composition of infiltrants can influence their physical properties, viscosity and depth of penetration (DP). Strategies are used to increase the DP, such as the addition of diluents or the use of heat. This study aimed to evaluate the effect of preheating and composition on physical properties and DP of infiltrants in demineralized enamel. The groups were assigned, and the following experimental formulations were made: 25%BisEMA +75%TEGDMA; 25%BisEMA +65%TEGDMA +10%ethanol; 25%BisEMA +65%TEGDMA +10%HEMA; 100%TEGDMA; 90%TEGDMA +10%ethanol; 90%TEGDMA +10%HEMA. The samples were photoactivated at two temperatures (25°C and 55°C). Degree of conversion (DC) was performed using an infrared spectrophotometer. Elastic modulus (E), flexural strength (FS) and contact angle (CA) tests were also performed. The DP of an infiltrant in demineralized enamel was determined by confocal laser scanning microscopy (CLSM) using an indirect labeling technique. The data were analyzed by two-way ANOVA and Tukey's test. DC increased after preheating in all the groups; however, 90%TEGDMA+10%ethanol showed the lowest DC for both temperatures, and the lowest E. Preheating did not influence E or FS. The CA increased at 55°C for most groups, but decreased for groups containing HEMA. Temperature did not seem to influence DP, and Icon showed the lowest DP values. The 100%TEGDMA composition showed more homogeneous penetration, whereas Icon showed heterogeneous and superficial penetration. The preheating technique does not improve all properties in all the material compositions. The composition of a material can influence and improve its properties.

Anti-caries effect of resin infiltrant modified by quaternary ammonium monomers

OBJECTIVES

Resin infiltrant is used in early enamel caries. However, commercial resin infiltrant lacks persistent antibacterial activity. Dimethylaminododecyl methacrylate (DMADDM) was added to resin infiltrant to give it sustainable antibacterial properties and inhibit demineralization.

METHODS

After the application of resin infiltrant to bovine enamel, cytotoxicity, surface roughness, and aesthetics were assessed. A multi-species biofilm was incubated on the enamel disk before and one month after microbial-aging. After a 48-h anaerobic incubation, biomass accumulation, metabolic activity, and lactic acid were analyzed using a crystal violet assay, an MTT (3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, and a lactic acid assay. Biofilm structure and composition were determined by live/dead staining, exopolysaccharide (EPS) staining, scanning electron microscopy (SEM), and quantitative polymerase chain reaction (qPCR). The depth and content of demineralization were tested by transverse microradiography (TMR).

RESULTS

Incorporating DMADDM did not increase the cytotoxicity or change the physical properties when the mass fraction of the DMADDM was 2.5-10 %. The modification decreased the amount of bacterial biofilm, metabolic activity, lactic acid production, EPS, and the proportion of Streptococcus mutans in the biofilms. It also provided anti-demineralization effects. The surface roughness and antibacterial ability were not changed after one month of microbial-aging.

CONCLUSION

The incorporation of DMADDM improved the antibacterial and anti-demineralization effects of the material. It demonstrated a sustained antibacterial effect.

CLINICAL SIGNIFICANCE

The antibacterial modification might be a potential choice for future clinical applications to inhibit early enamel caries.

Effect of Resin Infiltration Technique on Improving Surface Hardness of Enamel Lesions: A Systematic Review and Meta-analysis

OBJECTIVE

White spot lesion (WSL) is recognized as the first clinical sign of enamel caries; it is a very critical phase because it can be prevented from progression to frank caries by changing the surrounding destructive environment. The present study was undertaken to systematically review the effect of resin infiltration (RI) technique on surface hardness (SH) of WSL.

METHODS

Five electronic databases were searched with proper key words. Related titles and abstracts, up to October 2018, were screened, selected, and subjected to quality assessments. After collecting data, meta-analyses were carried out to compare the effect of RI with untreated WSL and sound enamel by using the STATA software.

RESULTS

A total of 4567 articles were included in the study after initial search. Finally, 10 studies were reliable enough in methodology to be included in the study. Metadata analyses, carried out on 7 studies that compared SH of RI group with untreated samples, showed a significant increase in SH with 3.66 mean difference (95% confidence interval = 2.56‒4.77, Q value = 36.07, I² = 83.4%). However, meta-analysis on 4 studies that compared SH of RI with sound enamel showed a significant decrease in SH with -2.35 overall mean difference (95% confidence interval = -3.91-0.98, P = .00, Q value = 31.75, I² = 90.6%).

CONCLUSION

The RI technique can enhance SH of WSL; however, regaining the SH of RI-treated WSLs similar to sound enamel is doubtful. Application of RI is more effective than other methods, including application of fluoride, enamel pro-varnish, adhesive, and colloidal silica infiltration for enhancing SH of WSLs.

Ex vivo investigation on internal tunnel approach/internal resin infiltration and external nanosilver-modified resin infiltration of proximal caries exceeding into dentin

This ex vivo proof-of-concept study aimed to investigate the effect of nanosilver particles (AgNP) added to a conventional infiltrant resin (Icon) on external penetration into natural proximal enamel caries exceeding into dentin after internal tunnel preparation and internal infiltration. Carious lesions (ICDAS codes 2/3) of extracted human (pre-)molars revealing proximal caries radiographically exceeding into dentin (E2/D1 lesions) were preselected. Then, 48 of those specimens showing demineralized areas transcending the enamel-dentin border as assessed by means of near-infrared light transillumination (DIAGNOcam) were deproteinized (NaOCl, 5%). Using an internal tunnel approach, occlusal cavities central to the marginal ridge were prepared. Excavation of carious dentin, total etch procedure (H3PO4, 40%), and internal resin infiltration (FITC-labeled) followed, along with final restorations (flowable composite resin). Outer lesion surfaces were etched (HCl, 15%) prior to external infiltration (RITC-labeled). Group 1 (control; n = 24) used non-modified infiltrant, while an infiltrant/AgNP mixture (20 nm; 5.5 wt%) was used with experimental Group 2 (n = 24). Non-infiltrated pores of cut lesions were stained (Berberine), and specimens were analyzed using confocal laser scanning microscopy. Compared to the non-filled infiltrant, incorporation of AgNP had no effect on the resin's external penetration. Between the groups, no significant differences regarding internal or external infiltration could be detected, and non-infiltrated lesion areas did not differ significantly (p>0.109; t-test). The internal tunnel preparation in combination with both an internal resin infiltration and an additional external infiltration approach using a nanosilver-modified infiltrant resin leads to increased infiltrated lesion areas, thus occluding and adhesively stabilizing the porous volume of the demineralized enamel. While exerting antimicrobial effects by the nanosilver particles, this approach should have the potential as a viable treatment alternative for proximal lesions extending into dentin, thus avoiding the sacrifice of sound enamel, postponing the frequently inevitable restoration/re-restoration cycle of conventional proximal caries treatment, and improving dental health.

Comparative Evaluation of Microhardness and Enamel Solubility of Treated Surface Enamel with Resin Infiltrant, Fluoride Varnish, and Casein Phosphopeptide-amorphous Calcium Phosphate: An In Vitro Study

Aim and objective

The aim and objective of this study was to do a comparative evaluation of microhardness and enamel solubility (ES) of the treated surface enamel with resin infiltrant, fluoride varnish, and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP).

Materials and methods

An in vitro study was conducted on freshly extracted 85 sound permanent teeth of which 5 teeth were subjected to check for microhardness by the Vickers microhardness tester and the remaining teeth were exposed to demineralizing solution to create initial enamel lesions. These 80 teeth were assigned to four groups: group I—negative control (n = 20), group II—resin infiltrant (n = 20), group III—fluoride varnish (n = 20), and group IV—CPP-ACP (n = 20), and microhardness was checked after application. These teeth were exposed to caries attack three times a day for three consecutive days. The ES of these four groups was checked by calcium ion loss in the artificial cariogenic solution and whole saliva by an atomic absorption spectrophotometer.

Results

It was found that none of the experimental groups reached the microhardness values of sound intact teeth. At 3rd day, the values of microhardness were: group II = group III > group IV > group I. Maximum ES was found for group I (control) followed with group IV.

Conclusion

All agents used in study remineralized initial carious lesion. Fluoride varnish has the highest microhardness and showed least ES compared to other remineralizing agents.

Clinical significance

Fluoride varnish can be regarded as the choice of material to be used for the treatment of incipient carious lesions because of the low application frequency (once every 3–6 months), requires minimal patient compliance as it is a noninvasive procedure and less time consuming.

How to cite this article

Dhillon SN, Deshpande AN, Macwan C, et al. Comparative Evaluation of Microhardness and Enamel Solubility of Treated Surface Enamel with Resin Infiltrant, Fluoride Varnish, and Casein Phosphopeptide-amorphous Calcium Phosphate: An In Vitro Study. Int J Clin Pediatr Dent 2020;13(S-1):S14–S25.

Adhesive systems effect over bond strength of resin-infiltrated and de/remineralized enamel

Background: The purpose of this study was to evaluate the effect of different bonding agents on bond-strength to demineralized enamel after remineralizing treatments and resin infiltration. Methods: Buccal enamel of 120 bovine incisors was polished and then were divided into five experimental groups: SE (sound enamel); DE (demineralized enamel); AS (demineralized enamel immersed in artificial saliva for eight weeks); NaF (demineralized enamel treated with 0.05% sodium fluoride solution (one minute) for eight weeks); Ic (demineralized enamel infiltrated with a low-viscosity resin (Icon-DGM). These groups were subdivided according to adhesive system used: self-etching adhesive Adper Easy One (3M/ESPE) and etch-and-rinse adhesive Single Bond (3M/ESPE). The composite resin blocks were fabricated using a Teflon matrix. A thermomechanical cycling machine was used to carry out the artificial aging of the specimens and thus were sectioned into sticks. The microtensile tests were performed using a universal testing machine at a cross-head speed of 1 mm/min. Data (in MPa) were subjected to two-way ANOVA and Tukey's tests (5%). Results: Significant differences were found for both factors tested and interactions (p<0.05). Tukey's test results of µTBS (mean ± SD) were: etch-and-rinse SE (28.79±3.93); DE (30.41±7.22); AS (29.03±3.33); NaF (29.81±4.06)a; Ic (29.47±5.5);  and self-etching SE (30.37±6.96); DE (14.62±4.47); AS (9.79±2.32); NaF (9.36±2.31); Ic (30.78±8.68).   Conclusions: Resin infiltration did not affect the bond strength of demineralized enamel for both adhesive systems tested. For etch-and-rinse adhesive, no differences were observed for the tested groups. For self-etching adhesive, only the resin-infiltrated group showed similar bond strength to sound enamel. Both etch-and-rinse and self-etching adhesive systems can be used in resin-infiltrated enamel, if a composite restoration needs to be further performed. In enamel that has undergone the de/remineralization process, the use of a total-etch adhesive might be preferable for the restorative procedure.

Is Resin Infiltration a Microinvasive Approach to White Lesions of Calcified Tooth Structures?: A Systemic Review

Aim

The treatment of white lesions should aim at arresting the lesion progression of carious lesions and improving the esthetics by diminishing the opacity of the developmental disturbances of a tooth. The objective of this review was to present the scientific basis, the principles of resin infiltration and to discuss its inherent clinical applications.

Data sources

Data were identified by PubMed searches. Papers published in English between 2010 and 2015 were selected and most up-to-date or relevant references were chosen.

Conclusion

The resin infiltration technique, while promising, needed more clinical evidence for conclusive findings. However, based on available laboratory and clinical studies, it seems convincing that resin infiltration of enamel lesions should aim at arresting the progression of white spot lesions. Combining this microinvasive approach with a substantial caries remineralization program may provide therapeutic benefits and significantly reduce both long term restorative needs and costs, thus complementing the concept of minimum intervention dentistry.

How to cite this article

Manoharan V, Kumar AS, et al. Is Resin Infiltration a Micro invasive Approach to White Lesions of Calcified Tooth Structures?: A Systemic Review. Int J Clin Pediatr Dent 2019;12(1):53-58.

Effect of resin infiltration and microabrasion on the microhardness, surface roughness and morphology of incipient carious lesions

OBJECTIVE

The effects of resin infiltration and microabrasion on incipient carious lesions by surface microhardness, roughness and morphological assessments, and resistance to further acid attack of treated lesions were evaluated.

MATERIAL AND METHODS

Eighty artificially-induced incipient lesions were randomly divided into five groups (n = 16): resin infiltration with an adhesive resin (Excite F, Ivoclar Vivadent, Schaan, Liechtenstein), resin infiltration with a resin infiltrant (Icon, DMG, Hamburg, Germany), microabrasion without polishing (Opalustre, Ultradent, South Jordan, UT, USA), microabrasion with polishing (Opalustre, Ultradent, Diamond Excel, FGM, Joinville, SC, Brazil), and distilled water (control group). All specimens were exposed to demineralization for another 10 d. Microhardness, roughness and morphological assessments were done at baseline, following initial demineralization, treatment and further demineralization. Data were analysed by the Kruskal-Wallis, Friedman's and Bonferroni tests (p < .05).

RESULTS

Enamel lesions treated with resin infiltrant and microabrasion demonstrated similar hardness values, with a nonsignificant difference compared with sound enamel. Resin infiltration demonstrated lower roughness values than those of microabrasion, and the values did not reach the values of sound enamel. Further demineralization for 10 d did not affect the hardness but increased the roughness of infiltrated and microabraded enamel surfaces. Polishing did not influence the roughness of microabraded enamel surfaces. After resin infiltration, porosities on enamel were sealed completely. The surface structure was similar to that of the enamel conditioning pattern for microabraded enamel lesions.

CONCLUSIONS

Within the limitations of this study, the icon infiltration and microabrasion technique appeared to be effective for improving microhardness. Icon appeared to provide reduced roughness, although not equal to sound enamel. Further research is needed to elucidate their clinical relevance.

In vitro effect of a resin infiltrant on different artificial caries-like enamel lesions

OBJECTIVES

A resin infiltrant was employed for the treatment of active white spot lesions due to its ability to penetrate into the enamel pores and prevent the progression of the lesion. However, limited information is available about its mechanical effect on different artificial enamel lesions as well as on its resistance to further demineralization. Therefore, this study aimed to evaluate the effects of the Icon® infiltrant on different artificial caries-like enamel lesions and its resistance to new acid challenges.

DESIGN

Artificial lesions were produced in bovine enamel using three different protocols (demineralization/remineralization cycling, DE-RE; 8% methylcellulose gel, MC; and methyl ethyl diphosphonate solution, MHDP; n = 13). The specimens were treated with Icon® and subjected to a new acid challenge using DE-RE cycling. The surface and cross-sectional hardness were evaluated in sound, demineralized, treated and further demineralized enamel areas. Data were statistically analyzed using ANOVA and Tukey's test (p < 0.05).

RESULTS

All of the demineralizing protocols produced subsurface artificial caries lesions. The infiltrant was able to partially recover the surface hardness and prevent further surface hardness loss in enamel previously demineralized using the DE-RE and MHDP protocols. In regard to cross-sectional hardness, no positive effect was found.

CONCLUSIONS

The effect of the infiltrant depends on the type of lesion created in vitro, and its action is limited to the lesion surface.

Effect of Resin Infiltration on Artificial Caries: An in vitro Evaluation of Resin Penetration and Microhardness

Aim

To evaluate the effectiveness of resin infiltration on artificial caries lesion by assessing the depth of resin penetration and the change in microhardness of lesion postinfiltration.

Materials and methods

Totally 45 human extracted premolars were used to create an artificial demineralized lesion in enamel using demineralizing solution. A total of 15 samples (group I) were infiltrated with resin. The depth of resin penetration was studied using scanning electron microscope (SEM). Other half (n = 30) of samples was equally divided into three subgroups and Vickers hardness number (VHN) values were obtained to measure the surface microhardness as group 11 a—before demineralization, 11 b—after demineralization, IIc—postresin infiltration.

Results

Mean depth of penetration in group I was 516.8 urn. There was statistically significant increase in VHN values of demineralized lesion postresin infiltration (independent Student’s t-test, p < 0.001).

Conclusion

Penetration depth of the resin infiltrant was deep enough to render beneficial effects, while significant increase in microhardness was observed postresin infiltration.

Clinical significance

Infiltrant used can be considered as a valid treatment option for noncavitated lesions.

How to cite this article

Prajapati D, Nayak R, Pai D, Upadhya N, Bhaskar VK, Kamath P. Effect of Resin Infiltration on Artificial Caries: An in vitro Evaluation of Resin Penetration and Microhardness. Int J Clin Pediatr Dent 2017;10(3):250-256.

Microhardness and Roughness of Infiltrated White Spot Lesions Submitted to Different Challenges

A white spot lesion is the first clinical sign of a caries lesion and represents mineral loss from the enamel subsurface. The purpose of this study was to evaluate the microhardness and surface roughness of white spot lesions after application of a resin infiltrant and subjection to different challenges. Caries-like lesions were induced in bovine enamel discs (n=50), and the specimens were randomly divided into five study groups (n=10): demineralized enamel (negative control, G1), infiltrated enamel (G2), infiltrated enamel submitted to brushing (G3), infiltrated enamel submitted to pH cycling (G4), and infiltrated enamel submitted to artificial aging (G5). Half of each enamel surface was used as its own positive control. Roughness data were analyzed using the Kruskal-Wallis test followed by the Dunn test. Results from microhardness were analyzed by two-way analysis of variance, followed by the Tukey test for multiple comparisons. The level of significance was set at 5%. Microhardness and roughness values obtained from the test side of the specimens were significantly lower compared with the sound enamel for all groups. Microhardness values obtained for G2, G3, and G5 were not significantly different. Values found for G1 were significantly lower compared with those for G2, G3, and G5. The lowest microhardness values were observed for G4, which was significantly different from the other groups. Surface roughness was not significantly different between G2 and G3. The resin infiltrant presented superiority over the unprotected white spot lesions, as they were more resistant to mechanical and aging challenges. However, resin infiltration was not able to reestablish the properties of sound enamel and was not resistant to a new cariogenic challenge.

Microhardness and Penetration of Artificial White Spot Lesions Treated with Resin or Colloidal Silica Infiltration

INTRODUCTION

Infiltration of early enamel lesions by materials having remineralizing capacity seems to improve aesthetics and arrests caries progression.

AIM

To evaluate and compare the surface microhardness and penetration depth of a low viscosity resin and colloidal silica nanoparticle infiltrates into artificially created white spot lesions.

MATERIALS AND METHODS

Forty extracted human central incisors were embedded in acrylic resin blocks exposing the labial surfaces of the crowns. The specimens were immersed in demineralizing solution for 96 hours to create white spot lesions on labial surfaces. The samples were then divided into two groups (n=20 each), where in Group 1-resin infiltration (ICON DMG, Hamburg, Germany) and Group 2-colloidal silica infiltration (Arrow Fine chemicals, Rajkot, Gujarat, India) was done. Samples were subjected to vicker's microhardness testing at baseline, after demineralization and after treatment with resin or colloidal silica infiltrates. Then, the crowns were sectioned longitudinally and penetration depth of the infiltrants was measured using confocal laser scanning microscope and compared the readings to lesion depth. All the collected data was subjected to statistical analysis using t-test.

RESULTS

Resin infiltration group showed significantly greater increase in microhardness compared to colloidal silica infiltration (p=0.001). The percentage of penetration of the resin group was 67.14% and that of colloidal silica group was 54.53% indicating significant difference between the two.

CONCLUSION

Resin infiltrates performed better in regaining the baseline microhardness and penetrating deep into the porous white spot lesions, when compared to colloidal silica infiltrates.

Comparison of the effect of resin infiltrant, fluoride varnish, and nano-hydroxy apatite paste on surface hardness and streptococcus mutans adhesion to artificial enamel lesions

Introduction

Dental caries is a major public health problem, and Streptococcus mutans is considered the main causal agent of dental caries. This study aimed to compare the effect of three re-mineralizing materials: resin infiltrant, fluoride varnish, and nano-hydroxy apatite paste on the surface hardness and adhesion of Streptococcus mutans as noninvasive treatments for initial enamel lesions.

Methods

This experimental study was conducted from December 2015 through March 2016 in Babol, Iran. Artificial enamel lesions were created on 60 enamel surfaces, which were divided into two groups: Group A and Group B (30 subjects per group). Group A was divided into three subgroups (10 samples in each subgroup), including fluoride varnish group, nano-hydroxy apatite paste group (Nano P paste), and resin infiltrant group (Icon-resin). In Group A, the surface hardness of each sample was measured in three stages: First, on an intact enamel (baseline); second, after creating artificial enamel lesions; third, after application of re-mineralizing materials. In Group B, the samples were divided into five subgroups, including intact enamel, demineralized enamel, demineralized enamel treated with fluoride varnish, Nano P paste, and Icon-resin. In Group B, standard Streptococcus mutans bacteria adhesion (PTCC 1683) was examined and reported in terms of colony forming units (CFU/ml). Then, data were analyzed using ANOVA, Kruskal-Wallis, Mann-Whitney, and post hoc tests.

Results

In Group A, after treatment with re-mineralizing materials, the Icon-resin group had the highest surface hardness among the studied groups, then the Nano P paste group and fluoride varnish group, respectively (p = 0.035). In Group B, in terms of bacterial adhesion, fluoride varnish group had zero bacterial adhesion level, and then the Nano P paste group, Icon-resin group, intact enamel group, and the de-mineralized enamel group showed bacterial adhesion increasing in order (p < 0.001).

Conclusion

According to the study among the examined materials, the resin infiltrant increased the tooth surface hardness as the intact enamel and fluoride varnish had the highest reduction level for bacterial adhesion. Nano P paste had an effect between the two materials, both in increasing surface hardness and reducing bacterial adhesion.

Evaluation of Surface Roughness Characteristics Using Atomic Force Microscopy and Inspection of Microhardness Following Resin Infiltration with Icon®

OBJECTIVE

The aim of this study was to evaluate the surface roughness via atomic force microscopy (AFM) as well as to evaluate the microhardness values of Icon^® in comparison with sound and demineralized enamel in a large subject group.

MATERIALS AND METHODS

Enamel samples were prepared from sound bovine incisors and randomly allocated into either AFM (n = 60) or microhardness (n = 60) groups. The AFM group was divided into control (n = 30) and Icon^® (n = 30) subgroups. The microhardness group was also divided into three subgroups: control (n = 20), demineralization (n = 20) and Icon^® (n = 20) groups. The demineralization and Icon^® subgroups were subjected to a demineralizing solution (pH: 4, 2 hours). Following the formation of shallow white spot lesions and application of the infiltrant, each sample was examined according to its parameter.

RESULTS

AFM images suggested that Icon^® had a significantly rougher surface than the control group. When the AFM results were evaluated numerically, it was evident that the Icon^® group possessed statistically higher Sa, Sq, mean height, and maximum deviation values compared to the control group. The mean Vickers hardness values of all groups were determined to be significantly different from one another. Hardness values in the demineralization group were determined to be significantly lower than the control and Icon^® groups. No statistically significant difference was observed between mean Vickers hardness values for the contol and Icon^® groups.

CONCLUSIONS

The present in vitro study shows that more studies are required to improve the surface quality of this infiltrant material.

CLINICAL SIGNIFICANCE

The present in vitro study shows that the resin infiltration technique results in increased microhardness of demineralized enamel. However, it was observed that the infiltrant material creates a significantly rougher surface compared to healthy, untreated enamel. (J Esthet Restor Dent 29:201-208, 2017).

Surface Properties and Color Stability of Resin-Infiltrated Enamel Lesions

OBJECTIVES

To examine the surface topographies, microhardness, and color stability of resin-infiltrated enamel lesions before and after aging challenges in vitro using three-dimensional laser scanning profilometry, surface microhardness testing, spectrophotometry, and scanning electron microscopy.

METHODS

Forty human third molars were embedded in epoxy resin, and each tooth was prepared to have two white spot lesions and one sound enamel area. One white spot lesion received resin infiltration and the other was untreated. Ten specimens were subjected to thermocycling for 10,000 cycles, 10 specimens were immersed in coffee solutions, and 10 specimens were placed in water storage. Surface area roughness (Sa), Vickers microhardness (VHN), and CIE L*a*b* color values were measured on sound enamel, resin-infiltrated lesions, and untreated lesions before and after aging. The surface morphology of resin-infiltrated lesions was observed after aging under scanning electron microscopy and compared with 10 specimens that were not subjected to aging challenge.

RESULTS

Resin infiltration increased the surface microhardness of the enamel lesions from 89.3 to 212.0 VHN. The surface microhardness of resin-infiltrated enamel lesions was not significantly affected by aging. The surface roughness of resin-infiltrated lesions (0.32-0.37 μm) was greater than that of sound enamel (0.05-0.06 μm) and untreated lesions (0.12-0.13 μm). Thermocycling and water storage further increased surface roughness of resin-infiltrated surfaces. Resin-infiltrated enamel lesions showed greater discoloration than sound enamel surfaces. Surface microfissures and microcracks were observed on resin-infiltrated enamel lesions after thermocycling.

CONCLUSIONS

Surface hardness of enamel lesions increased significantly after resin infiltration and remained stable following thermocycling. Surface roughness and color stability of resin-infiltrated enamel lesions were less than ideal and might further deteriorate after aging in the oral environment.

Hydrolytic and Color Stability of Resin Infiltration: A Preliminary in vitro Trial

AIMS

Resin infiltration is an emerging technique for management of noncavitated lesions. This study evaluated the in vitro hydrolytic and color stability of the ICON® resin infiltration system (IC) in 42 extracted human teeth.

MATERIALS AND METHODS

ICON® resin infiltration system was compared with dental adhesive (DA) and dental sealant (DS). The products were applied according to manufacturer's instructions. The baseline weight and color of the samples were recorded. Color was recorded by spectoral colorimeter. The samples were subjected to four experimental conditions: (1) group 1: Stored in lactic acid solution (pH 4.9) for 24 hours; (2) group 2: Thermocycled for 100 cycles (temperatures: 5°C, 55°C, and dwell time of 15 seconds); (3) group 3: Stored in 0.1 N sodium hydroxide solution (pH 12.48) for 14 days at 60°C; (4) group 4: Stored in phosphate-buffered saline solution (pH 7.2) at 37°C for 4 months. The weight and color were recorded again after removal of the samples from the experimental conditions. Two-factor analysis of variance models and Tukey's Honestly Significant Difference were performed to assess statistical differences among the groups. Scanning electron microscopy imaging was performed for samples from groups 1, 3, and 4.

RESULTS

All the samples showed loss of material and change in color. In the demineralizing solution, IC showed significantly greater weight loss (p = 0.032) and color change (p = 0.038) compared with DA. Dental Sealant showed significantly greater weight loss than IC (p = 0.027) after thermocycling. Teeth in group 3 exhibited the greatest weight loss (p < 0.001). Teeth in group 2 exhibited the greatest color change (p < 0.001).

CONCLUSION

All tested materials showed loss of retention and color change in the experimental conditions. Infiltration system exhibited greatest weight loss and color change in demineralizing solution. Dental sealant exhibited greatest weight loss upon thermocycling.

CLINICAL SIGNIFICANCE

Clinicians should be cautious about the limitations of retention and color stability when considering resin infiltration for incipient lesions.

Effect of resin infiltration on enamel surface properties and Streptococcus mutans adhesion to artificial enamel lesions

The aim of this study was to evaluate and compare the effects of resin infiltration and sealant type on enamel surface properties and Streptococcus mutans adhesion to artificial enamel lesions. Artificial enamel lesions were produced on the surfaces of 120 enamel specimens, which were divided into two groups: Group A and Group B (n=60 per group). Each group was further divided into four subgroups (n=15 per subgroup) according to sealant type: Group I-Demineralized enamel (control); Group II-Enamel Pro Varnish; Group III-ExciTE F; and Group IV-Icon. In Group A, hardness and surface roughness were evaluated; in Group B, bacterial adhesion was evaluated. Icon application resulted in significantly lower surface roughness and higher hardness than the other subgroups in Group A. In Group B, Enamel Pro Varnish resulted in lowest bacterial adhesion, followed by Icon. This study showed that resin infiltration of enamel lesions could arrest lesion progress.

Effect of resin infiltration on the nanomechanical properties of demineralized bovine enamel

Objective:

The aim of the present study was to evaluate the efficacy of resin infiltration in preventing in vitro lesion progression.

Materials and Methods:

Buccal surfaces of bovine incisors were divided into mesial and distal regions and, at the center, nail varnish was applied (1.0 mm width) to protect the enamel surface against any further treatment. In order to create artificial enamel lesions in the unprotected areas, each specimen was soaked in a demineralizing solution. After that, specimens had two enamel lesions. One lesion in each sample was etched with 15% HCl for 120 s and infiltrated with a commercial infiltrating resin for 3 min, while the other lesion was not treated (control). Each specimen was cross-sectionally halved and randomly allocated to two groups: Group 1 was immediately processed and Group 2 was submitted to a new demineralization process. The samples were analyzed by means of cross-sectional hardness measurements using a nanoindenter equipment. Hardness data were statistically analyzed by non-parametric Kruskal-Wallis and MannWhitney tests (α = 0.05).

Results:

The findings showed statistical difference between treatments at the same analyzed distance range from the outer surface of the enamel (P < 0.05).

Conclusion:

The untreated lesion showed lower hardness values for distances near the outer surface of the enamel. The resin infiltration was efficient in preventing further in vitro demineralization of bovine enamel lesions.

In Vitro Progression of Artificial White Spot Lesions Sealed With an Infiltrant Resin

This study assessed the ability of an infiltrant resin (Icon, DMG Chemisch-Pharmazeutische Fabrik GmbH, Hamburg, Germany) to prevent artificial lesion progression in vitro when used to impregnate white spot lesions and also assessed the effect of saliva contamination on resin infiltration. Enamel specimens (n=252) were prepared and covered with nail varnish, leaving a window of sound enamel. After demineralization (pH 5.0; four weeks), specimens were divided into six groups (n=42 per group): group 1, 2% fluoride gel (positive control); group 2, resin infiltrant; group 3, resin infiltrant + fluoride gel; group 4, no treatment (negative control); group 5, resin infiltrant application after saliva contamination; and group 6, resin infiltrant + fluoride gel after saliva contamination. Specimens from each group were cut perpendicular to the surface, and one-half of each specimen was exposed to a demineralizing solution for another four weeks. The other half was set aside as a record of initial lesion depth and was used later in the determination of lesion progression. Lesion progression and infiltrant penetration were measured using confocal laser scanning microscopy (CLSM) and transverse microradiography (TMR). For lesion depth, based on CLSM, groups 2 and 3 showed the least changes when submitted to demineralization challenge, followed by group 1, then groups 5 and 6, and finally group 4. There were no significant differences between groups 2 and 3 or groups 5 and 6 in their ability to inhibit further lesion progression (p&lt;0.05). Based on TMR, groups 2 and 3 also showed the fewest changes when submitted to demineralization challenge, followed by group 5, then groups 1 and 6, and finally group 4. In terms of mineral loss as measured by TMR, all groups that contained fluoride (groups 1, 3, and 6) show less percentage change in mineral loss than the groups that did not contain fluoride (groups 2, 4, and 5). It can be concluded that infiltrant penetration into early enamel lesions inhibited further demineralization in vitro, especially in the presence of fluoride. Saliva contamination decreased the ability of the infiltrant to prevent further demineralization, but the presence of fluoride seemed to counteract this effect.

Color masking of developmental enamel defects: a case series

Developmental defects involving color alteration of enamel frequently compromise the esthetic appearance of the tooth. The resin infiltration technique represents an alternative treatment for color masking of these lesions and uniformization of tooth color. This technique is considered relatively simple and microinvasive, since only a minimal portion of enamel is removed. This article illustrates the color-masking effect with resin infiltration of fluorosis and traumatic hypomineralization lesions with a case series. The final esthetic outcomes demonstrated the ability of the resin infiltrant to mask the color of white developmental defect lesions, resulting in satisfactory clinical esthetic improvements. However, in more severe cases, the color-masking effect was not complete.

Micro-hardness and mineral loss of enamel lesions after infiltration with various resins: influence of infiltrant composition and application frequency in vitro

OBJECTIVES

The aim of this in vitro study was to evaluate the influence of infiltrant composition and application frequency on micro-hardness and lesion progression after resin infiltration of artificial enamel lesions.

METHODS

In each of 100 bovine enamel samples, three artificial caries lesions were created (pH=4.95, 50 days). After etching two of the lesions (37% phosphoric acid) specimens were randomly allocated to five infiltrants (four experimental infiltrants with different monomer and solvent compositions and penetration coefficients, and one commercial infiltrant [Icon, DMG]). Lesions were then infiltrated and light-cured, and infiltration repeated afterwards for one of the lesions. Infiltrated samples were cut into halves, with one half being demineralised for further 50 days. Micro-hardness (VHN) and integrated mineral loss (ΔZ) were evaluated at baseline and after second demineralisation. Repeated measures ANOVA and paired t-tests were used to analyse influence of material composition and application frequency on micro-hardness and lesion progression (integrated mineral loss difference ΔΔZ).

RESULTS

Resin infiltration significantly increased micro-hardness and reduced lesion progression compared to untreated artificial lesions (p<0.05, t-test). Neither micro-hardness nor lesion progression were significantly influenced by material composition (p>0.05, ANOVA). In contrast, twice application resulted in significantly increased micro-hardness and demineralisation resistance of infiltrated lesions (p<0.05, ANOVA).

CONCLUSION

Resin infiltration significantly improves micro-hardness and demineralisation resistance of enamel lesions; these effects are significantly enhanced if resins are applied twice. Experimental resins did not outperform the commercial infiltrant.

CLINICAL SIGNIFICANCE

This in vitro study demonstrated that resin infiltration significantly increases both micro-hardness and demineralisation resistance of enamel caries lesions. Twice application of the infiltrant seems to increase these effects. In contrast, the composition of the infiltrant had no significant influence on investigated parameters.