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

Remineralizing effect of the association of nano-hydroxyapatite and fluoride in the treatment of initial lesions of the enamel: A systematic review

OBJECTIVE

Assessed the effect of dental products containing nano-hydroxyapatite (nano-HA) + fluoride on the remineralization of white spot lesions (WSL) in vivo or in situ.

METHODS

Seven databases were explored using a two-pronged approach (intervention/treatment). After screening, full-text assessment, and further exclusion, the qualitative synthesis of five studies (four clinical and one in situ) was performed. Based on the Cochrane collaboration guidelines relevant data of the studies were collected and summarized. The Cochrane risk of bias tool for randomized trials (RoB 2.0) was used to appraise the studies' methodological quality and the GRADE guidelines to assess their level of evidence. The RoB 2.0 domains were rated on their risk of bias (RoB) as low, high, or with some concerns, and an adaptation of the tool was used to the in situ study.

RESULTS

The included studies assessed 151 WSL in anterior permanent teeth, on patients with varying ages. The protocol application, treatment length (7d-12 w), and control groups varied greatly between the studies making the performance of a quantitative analysis unfeasible. The general RoB of the clinical studies was classified as being of low risk (n = 2) or some concerns (n = 2). The in situ study was considered as being of low risk. The level of the evidence was moderate. Most of the studies found moderate evidence regarding the superiority of this association in clinical settings.

CONCLUSION

Even with the nano-HA + fluoride promising results for the remineralization treatment of WSL, due to the restricted number of studies and types of products, its extended use cannot be recommended based on the current systematic review, especially when considering the moderate level of the evidence found.

CLINICAL SIGNIFICANCE

Due to the biocompatibility and higher surface coverage of nano-HA and the remineralization capacity of fluoride formulations, the association of these elements to remineralize WSL has been positively reported. After the collection and qualitative appraise of the data, the clinical evidence of the use of these dental products is promising but limited.

Fluoride-amorphous calcium phosphate and biomimetic nano-hydroxyapatite for enamel remineralization: An in-vitro study of surface microhardness and composition

AIM

Fluoride-Amorphous Calcium Phosphate and Biomimetic Nano-Hydroxyapatite for Enamel Remineralization; An In-Vitro Study of Surface Microhardness and Composition.

MATERIAL AND METHODS

Ninety-six extracted human premolars with sound buccal surface were divided using a randomization computer-generating software into four groups; Group I (control) sound untreated enamel, Group II (demineralized) demineralized to create white spot lesions, Group III (biom-n-HA) demineralized and then treated with biomimetic nanohydroxyapatite cream, and Group IV (F-ACP) demineralized and then treated using Fluoride-Amorphous Calcium Phosphate varnish. Each group was divided into two subgroups; subgroup "A" evaluated for mineral content using energy dispersive x-ray spectroscopy (EDX) and for surface microhardness using the Vickers microhardness test and Subgroup "B" evaluated for white spot lesion depth using a polarized light microscope (PLM).

RESULTS

The highest microhardness (VHN) was found in the (F-ACP) group (mean=428.61±54.43) and then in the (Biom-n-HA) group (mean=408.11±70.16) followed by the (Control) group (mean=402.13±53.40) with no significant difference between them and finally in the significantly different (Demineralized) group (mean=256.99±45.83). The weight percentage of Ca (30.29±1.04 and 33.44±1.07) and Ca/P ratio (1.87±0.06 and 2.03±0.05) were significantly different between Group III and Group IV respectively. PLM measurements in Group II (198.83μm), Group III (60.17μm), and Group IV (26.33μm) were significantly different.

CONCLUSIONS

Both the (Biom-n-HA) cream and the (F-ACP) varnish showed promising results for enamel remineralization. The increased enamel surface microhardness was consistent with the mineral content and the changes in the birefringence.

The effect of combined use of resin infiltration with different bioactive calcium phosphate-based approaches on enamel white spot lesions: An in vitro study

OBJECTIVES

This in vitro study aimed to evaluate the effect of resin infiltration combined with casein phosphopeptide-amorphous calcium phosphate with fluoride (CPP-ACPF) or bioactive glass (BAG) on the stability of enamel white spot lesions (WSLs) treatment.

MATERIALS AND METHODS

Eighty-four enamel blocks were prepared from the buccal surfaces of sound human premolars. All enamel blocks were placed in a demineralisation solution for 3 days to establish the artificial enamel WSLs. Enamel blocks with WSLs were randomly divided into three groups (n = 28 each group): RI/B: one-off resin infiltration followed by twice daily BAG treatment; RI/C: one-off resin infiltration followed by twice daily CPP-ACPF treatment; RI: one-off resin infiltration treatment only (as control) and subjected to pH cycling for 7 days. Surface morphology, elemental analysis, crystal characteristics, surface roughness and microhardness of enamel surfaces were investigated by scanning electron microscopy and energy-dispersive spectrometry observation, X-ray diffraction (XRD), atomic force microscope and Vickers' hardness testing, respectively.

RESULTS

Mean values of the surface roughness (mean±standard deviation (nm)) were 24.52±5.07, 27.39±5.87 and 34.36±4.55 for groups RI/B, RI/C and RI respectively (p = 0.003). The calcium to phosphate ratios were 1.32±0.16, 1.22±0.26 and 0.69±0.24 for groups RI/B, RI/C and RI respectively (p < 0.001). XRD revealed apatite formation in all three groups. The mean enamel surface microhardness (kg/mm2) of the groups were 353.93±28.49, 339.00±27.32 and 330.38±22.55 for groups RI/B, RI/C and RI respectively (p = 0.216).

CONCLUSIONS

Resin infiltration combined with CPP-ACPF or BAG remineralisation appears to improve the surface properties of WSLs.

CLINICAL SIGNIFICANCE

The combination of resin infiltration and CPP-ACPF/BAG remineralisation may be a potential treatment for the management of the WSLs.

Durability of infiltrated resin application on white spot lesions after different challenges: An ex vivo study

STATEMENT OF PROBLEM

Infiltrated resin has been widely used as a minimally invasive approach to masking white spot lesions and reinforcing demineralized enamel. Recent evidence confirms its satisfactory effect in the short term, but studies focusing on its long-term performance are lacking.

PURPOSE

The purpose of this ex vivo study was to evaluate the durability of infiltrated resin on white spot lesions after pH cycling and long-term thermocycling, staining, and toothbrushing.

MATERIAL AND METHODS

Four axial surfaces of 25 extracted human molars were sectioned and fabricated as specimens. The enamel surface of each specimen was prepared in 3 areas: sound enamel, demineralized enamel (white spot lesions), and demineralized enamel treated by infiltrated resin. Then, 4 specimens of each molar were allocated to different challenges simulating a 10-year follow-up: pH cycling, thermocycling, staining, and toothbrushing. The surface roughness, microhardness, and CIELab color values were measured before and after different treatments. A scanning electron microscope (SEM) was used to observe representative specimens. Linear mixed models were used to evaluate the effect of different treatments on microhardness, roughness, and color differences (ΔE) (α=.05).

RESULTS

Resin infiltration reduced the surface roughness and increased the microhardness of demineralized lesions, (P<.001) but the values of sound enamel at baseline were not reached. The pH cycling led to the greatest roughness values (515.6 ±56.9 nm) on resin-infiltrated lesions, followed by thermocycling (450.7 ±64.7 nm), toothbrushing (291.2 ±43.5 nm), and staining (183.6 ±49.3 nm) (all P<.001). Only pH cycling significantly decreased the microhardness of resin-infiltrated lesions (81.6 ±14.8 HV 0.2) after progressive demineralization (P<.001). No clinically identified differences were found between resin-infiltrated white spot lesions and sound enamel (ΔE=3.4 ±2.0) at baseline. However, resin-infiltrated lesions demonstrated significantly greater discoloration after pH cycling (ΔE=8.0 ±4.5, P<.001), thermocycling (ΔE=5.4 ±2.0, P=.014), and staining treatments (ΔE=10.4 ±3.2, P<.001) than sound enamel.

CONCLUSIONS

Infiltrated resin application reduced surface roughness, improved microhardness, and masked white spot lesions immediately. However, it could not reestablish the characteristics of sound enamel completely and resist chemical and mechanical challenges over time.

Influence of resin infiltration pretreatment on the microleakage under orthodontic bracket (an in vitro study)

OBJECTIVES

In order to assess the changes in tooth orthodontic adhesive interface microleakage after applying a caries resin penetrated to the sound enamel tooth surface in different storage media.

MATERIALS AND METHODS

A total of 60 human maxillary first premolars (orthodontic extraction) were collected by random separation of the teeth into two equal groups. The control group was classified into three subgroups (n = 10) (control in deionized water, control in milk, and control in energy drink), while the experimental one (treated with ICON) was categorized into three subgroups (n = 10) (ICON in deionized water, ICON in milk, and ICON in energy drink) incubation phase lasted three weeks in total.

RESULTS

A one-way analysis of variance (ANOVA) yielded a significant difference between all experimental subgroups (ICON in deionized water, ICON in milk, and ICON in energy drink) and control subgroups (control in deionized water, control in milk, and control in energy drink). The control group in the energy drink subgroup had the highest mean microleakage value when compared to the other subgroups, whereas the resin-infiltrated group in deionized water had the lowest mean value. According to the results of the T-test, ICON pre-treatment tooth samples had significantly lower mean values of microleakage than non-ICON tooth samples.

CONCLUSIONS

The adhesive system (control group) revealed that a resin infiltrate on a sound enamel surface prior to orthodontic bracket bonding reduced bracket tooth interface microleakage in all examined samples. The ICON-infiltrated surface was discovered to provide a secondary preventive strategy against white spot lesion development by reducing microleakage under brackets.

The effect of calcium phosphate ion clusters in enhancing enamel conditions versus Duraphat and Icon

This study aimed to evaluate and compare the remineralisation, mechanical, anti-aging, acid resistance and antibacterial properties of calcium phosphate ion clusters (CPICs) materials with those of Duraphat and Icon. The remineralisation and mechanical properties were investigated using scanning electron microscopy, Fourier-transform infrared (FTIR) spectroscopy and nanoindentation. CPICs induced epitaxial crystal growth on the enamel surface, where the regrown enamel-like apatite layers had a similar hardness and elastic modulus to natural enamel (p > 0.05). Acid resistance and anti-aging properties were tested based on ion dissolution and surface roughness. CPICs exhibited similar calcium and phosphate ion dissolution to the control (p > 0.05), and its roughness decreased after thermocycling (p < 0.05), thereby decreasing the risk of enamel surface demineralisation. The minimum inhibitory concentration was 0.1 mg/ml, and the minimum bactericidal concentration ranged from 0.05 to 0.1 mg/ml. Overall, this biomimetic CPICs is a promising alternative to dental demineralisation.

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 remineralization effect of GERM CLEAN on early human enamel caries lesions in vitro

This study aimed to evaluate the remineralization effect of GERM CLEAN, a novel antibacterial peptide, on early enamel caries. Thirty human enamel blocks from thirty teeth were randomly divided into three groups: double distilled water (DDW group), GERM CLEAN (GC group), and 1000 ppm fluoride (NaF group). Specimens were demineralized for 3 days (pH 4.6) followed by pH cycling twice daily for 14 days. For a pH cycle, specimens received corresponding treatments for 5 min, then were immersed in demineralizing solution for 1 h, received corresponding treatments again, and finally were immersed in remineralizing solution (pH 7.0) for approximately 11 h. Specimens were washed with DDW after each treatment. Microindentation tests, atomic force microscopy (AFM), and transverse micro-radiography (TMR) were conducted to analyze enamel blocks. GC demonstrated a lower percentage of surface microhardness recovery (SMHR%) (p < 0.0001), rougher surfaces (p < 0.0001), deeper lesion depth (p = 0.001), and more mineral loss (p = 0.001) than NaF, but showed higher SMHR% (p < 0.0001), smoother surfaces (p < 0.0001), shallower lesion depth (p = 0.049), and less mineral loss (p = 0.001) than DDW. As a result, GERM CLEAN has the potential to promote the remineralization of demineralized enamel.

An Insight into Enamel Resin Infiltrants with Experimental Compositions

Resin infiltration is a conservative treatment of initial enamel carious lesions. Only one infiltrant material is available on the market (Icon, DMG), and research is now investigating new chemical compositions so as to further exploit the benefits of the resin infiltration technique. A literature search of the articles testing the effects of different formulations on mechanical properties, resin penetration ability, remineralizing, and antibacterial activities was conducted. Of 238 articles, 29 resulted in being eligible for the literature review. The formulations investigated were all different and consisted in the inclusion of hydrophobic monomers (i.e., BisEMA, UDMA), solvents (ethanol, HEMA), alternative etchants (PAM) or molecules with antibacterial or bioactivity features (i.e., AgNP, YbF_3, MTZ, chitosan, DMAMM, HAp, MC-IL, NACP, PUA, CHX) and microfilled resins. Information on the long-term performances of the tested experimental materials were scarce. The combination of TEGDMA with hydrophobic monomers and the inclusion of a solvent alternative to ethanol reinforced mechanical properties of the materials. Hybrid-glass materials demonstrated an enhanced remineralization capacity. Techniques such as tunnelization increased the penetration depth and preserved the recourse to less-conservative treatments. Combining the min-invasive infiltrant approach with remineralizing and bacteriostatic properties would be beneficial for therapeutic and economical aspects, according to the principles of minimally invasive dentistry.

Resin Infiltration of Non-Cavitated Enamel Lesions in Paediatric Dentistry: A Narrative Review

The resin infiltration (RI) technique was introduced as one of the minimal intervention dentistry strategies in addressing dental caries among the paediatric population. This technique used the low-viscosity resin monomer to infiltrate the non-cavitated carious lesion and other developmental enamel porosities, thus allowing the conservation of the tooth structure. This narrative review aims to explore the value of RI in Paediatric Dentistry. Through our search of the literature, the development of the material, their clinical applications and shortcomings, as well as the innovation that has been carried out to improve the current RI, were discussed. There are number of high-level evidence supporting the use of RI in arresting non-cavitated proximal caries lesions in primary and permanent teeth, but its efficacy in managing anterior white spot lesions is still unclear. Limited penetration depth, not radiopaque and questionable long-term colour and material stability were among the limitation of the material. Various laboratory-based studies have been conducted to improve the current properties of RI. Nevertheless, RI has emerged as one of the important micro-invasive techniques in addressing non-cavitated and anterior white-spot enamel lesions in children and adolescents with great success.

Novel dental resin infiltrant containing smart monomer dodecylmethylaminoethyl methacrylate

Objectives

White spot lesions (WSLs) are prevalent and often lead to aesthetic problems and progressive caries. The objectives of this study were to: (1) develop a novel resin infiltrant containing smart monomer dodecylmethylaminoethyl methacrylate (DMAEM) to inhibit WSLs, and (2) investigate the effects of DMAEM incorporation on cytotoxicity, mechanical properties, biofilm-inhibition and protection of enamel hardness for the first time.

Methods

DMAEM was synthesized using 1-bromododecane, 2-methylamino ethanol and methylmethacrylate. DMAEM with mass fractions of 0%, 1.25%, 2.5% and 5% were incorporated into a resin infiltant containing BisGMA and TEGDMA. Cytotoxicity, mechanical properties and antibacterial effects were tested. After resin infiltration, bovine enamel was demineralized with saliva biofilm acids, and enamel hardness was measured.

Result

DMAEM infiltration did not increase the cytotoxicity or compromise the physical properties when DMAEM mass fraction was below 5% (p > 0.05). Biofilm metabolic activity was reduced by 90%, and biofilm lactic acid production was reduced by 92%, via DMAEM (p < 0.05). Mutans streptococci biofilm CFU was reduced by 3 logs (p < 0.05). When demineralized in acid and then under biofilms, the infiltrant + 5% DMAEM group produced an enamel hardness (mean ± sd; n = 6) of 2.90 ± 0.06 GPa, much higher than 0.85 ± 0.12 GPa of the infiltrant + 0% DMAEM group (p < 0.05).

Significance

A novel resin infiltrant with excellent mechanical properties, biocompability, strong antibacterial activity and anti-demineralization effect was developed using DMAEM for the first time. The DMAEM resin infiltrant is promising for inhibiting WSLs, arresting early caries, and protecting enamel hardness.

Effects of hybrid inorganic-organic nanofibers on the properties of enamel resin infiltrants - An in vitro study

This in vitro study aimed to evaluate the overall mechanical properties of resin infiltrants doped with bioactive nanofibers and their ability in inhibiting enamel demineralization or achieving remineralization of the adjacent enamel to white spots. A commercial resin infiltrant (ICON, DMG) was doped with hybrid inorganic-organic nanofibers and analyzed for degree of conversion (DC, n = 3) and surface hardness (SH, n = 6). Subsequently, enamel specimens (6 × 4 × 2 mm³) were prepared and submitted to a demineralizing/remineralizing process to produce a subsurface caries-like lesion. The specimens were treated with one of the following materials: ICON infiltrant, DMG (control); ICON + nanofibers of poly-lactic acid (PLA)-filled with silica (PLA-SiO₂); ICON + nanofibers of (PLA)-filled with calcium incorporated into a silica network (SiO₂-CaP). Then, the specimens were subjected to a pH-cycling demineralizing/remineralizing model for 7 days at 37 °C. The %ΔSH change (after treatment), %SH loss and %SH recovery (after pH-cycling regimen) were calculated after SH evaluation (n = 9/group). The Ca/P weight ratio before and after pH-cycling regimen was evaluated through SEM/EDX. The results of DC were analyzed through the T-test (p < 0.05). ANOVA followed by Tukey's test (p < 0.05) was performed for hardness and EDX. A significant SH increase was observed in the ICON/SiO₂CaP group (p < 0.05). The ICON/PLA-SiO₂ presented higher DC values than the control group (p = 0.043). All groups presented significant difference in %ΔSH (p < 0.05), although the specimens treated with ICON/SiO₂CaP presented greater values. Regarding the %SHL and %SHR, the ICON/SiO₂CaP and ICON/PLA-SiO₂ were significantly different compared to the control group (p < 0.001). However, no difference was observed between the ICON/SiO₂CaP and ICON/PLA-SiO_2. The Ca/P ratio showed that the ICON/SiO₂CaP and ICON/PLA-SiO₂ after the pH-cycling regimen differed from sound enamel and modified infiltrants before pH-cycling. In conclusion, tailored hybrid nanofibers may be incorporated into enamel resin infiltrants without compromise the mechanical properties of such experimental materials. These latter can inhibit the demineralization of enamel and increase its hardness during pH-clycling challange.

Real-Time Monitoring and Quantitative Evaluation of Resin In-Filtrant Repairing Enamel White Spot Lesions Based on Optical Coherence Tomography

The aim of the present study was to explore the feasibility of real-time monitoring and quantitative guiding the repair of enamel white spot lesions (WSLs) with resin infiltration by optical coherence tomography (OCT). Seven New Zealand rabbits were treated with 37% phosphoric acid etchant for 15 min to establish the model of enamel demineralization chalk spots of upper incisors, which were repaired by Icon resin infiltrant. OCT, stereo microscope (SM) imaging, scanning electron microscope (SEM) imaging and hematoxylin eosin (HE) staining were used to image each operation step. The changes of WSLs of enamel before and in the process of restoration with resin infiltrant showed specific performance in OCT images, which were consistent with the corresponding results of stereomicroscope and SEM. OCT can non-invasively and accurately image the whole process of repairing enamel demineralization layer with resin infiltration real-time, which can effectively guide the clinical use of resin infiltrant to repair enamel WSLs and be used as an imaging tool to evaluate the process and effect of restoration with resin infiltrant at the same time.

Effect of Ageing Process and Brushing on Color Stability and Surface Roughness of Treated White Spot Lesions: An in vitro Analysis

Purpose

To evaluate the effect of ageing process and brushing on the color stability and surface roughness of white spot lesions treated with resin infiltration or remineralization.

Patients and Methods

Artificial white spot lesions were created on the facial surface of extracted bovine teeth. Specimens were divided into three main groups based on treatment received: resin infiltration (Icon), MI Paste Plus (MI) or no treatment (control). Specimens underwent pH cycling for 7 days, followed by brushing with toothbrush simulator. Specimens were then immersed in three different solutions (water, cranberry juice, or coffee) for 7 days. Surface roughness (SR) and color stability (CS) assessments were performed at baseline and after each test. One-way and two-way ANOVA were used to calculate the statistical comparisons between the groups and significance considered at P <0.05.

Results

Icon group had the least color change after pH cycling, while MI showed the least color change after brushing test. Immersion in coffee produced the highest color change in all groups, followed by cranberry juice. Icon group had the best color stability when immersed in cranberry juice or coffee. Control and the MI treated specimens showed gradual increase of SR after pH cycling and brushing test, while Icon group had improved surface properties. Brushing test alone produced less color change in comparison with immersion in cranberry juice and coffee; however, brushing increased SR.

Conclusion

Icon treatment showed superior color stability and surface roughness, compared to the control and the MI treated teeth. Brushing had less influence on color change compared to the immersion in cranberry juice or coffee.

Assessment of the Potential Ability to Penetrate into the Hard Tissues of the Root of an Experimental Preparation with the Characteristics of a Dental Infiltratant, Enriched with an Antimicrobial Component-Preliminary Study

Infiltration is a method of penetration with a low viscosity resin that penetrates deep into demineralised tooth tissue and fills the intergranular spaces, hence reducing porosity. Carious lesions initially located at the enamel–cement junction are usually found in elderly patients. Those spots are predisposed to bacterial adhesion originating both from biofilm and from gingival pocket bacteria. The aim of this study was to evaluate the penetration of an experimental preparation, which has the characteristics of a dental infiltrant, enriched with an antibacterial component, into the decalcified root cement tissues of extracted human teeth in elderly patients. An experimental preparation with the characteristics of a dental infiltrant was prepared, applied, and polymerised on the surface of extracted, previously decalcified human teeth. The control sample was Icon (DMG, Hamburg, Germany). The ability of the preparations to penetrate deep into the root cement was evaluated using scanning electron and light microscopy. The study showed that an experimental preparation could potentially be used for treatment of early carious lesions within the tooth root in elderly patients, among others, as it penetrates deep into demineralised tissues. More research is needed.

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.

Study of Cytotoxic Properties of an Experimental Preparation with Features of a Dental Infiltrant

Microinvasive dentistry is based on the treatment of early carious lesions with the use of dental infiltrants. The commercially available Icon dental infiltrant does not contain any bacteriostatic component. An experimental preparation enriched with the missing component was synthesised. The aim of this study was to evaluate the cytotoxicity of the experimental preparation. Mouse fibroblasts of the L-929 lineage were used for the in vitro study. Cell morphology and viability were assessed. In the cytotoxicity analysis, it was shown that the experimental preparation (42.8 ± 10.3) after 24 h at two-fold dilution showed similar cytotoxicity to Icon (42.7 ± 8.8) (p > 0.05), while at four-fold dilution experimental preparation (46.7 ± 3.1), it was less toxic than Icon (34.2 ± 3.1) (p < 0.05). The experimental preparation has the potential to provide an alternative to the Icon commercial preparation. Further research is needed to evaluate the cytotoxicity of the experimental preparation over a longer period of time.

Resin Infiltration in Dental Fluorosis Treatment-1-Year Follow-Up

Background and objective: Dental fluorosis is a disease affecting dental hard tissues featured with white or yellowish lesions. Several treatments are proposed in the literature, some even invasive. This clinical study aimed to evaluate the effectiveness of resin infiltration in terms of lesions resolution, trend of sensitive teeth and satisfaction of patients over time. Methods and material: 200 fluorosis lesions were treated using ICON infiltrating resin (DMG, Hamburg, Germany). Parameters related to patients were collected by a questionnaire and analyzed aesthetic dissatisfaction about lesions, Shiff Air Index Sensitive Scale, sensitive teeth after treatment, the satisfaction of duration of treatment. The same operator measured dimensions of lesions Tooth Surface Index of Fluorosis (TSIF) and numbers of etching cycles needed for treating lesions. Statistical analysis was performed. The follow-up was of 1-year a measurement were performed at baseline (t0), immediately after the treatment (t1) and every three months during the observation period. Results: All lesions disappeared after one treatment. Pain or sensitive teeth were reported inside the 72 h and they disappeared after. Statistical analysis showed highly statistically correlation between etching cycles and the dimension of lesions and TSIF at the time-points evaluated as well as for pain during treatment, whereas a statistical significance was not noticed where etching cycles were correlated to sensitive teeth after 72 h. Overall, the treatment was found to be statistically significantly associated with differences in answers of aesthetic dissatisfaction between t0 and t1 and those collected between t1 and t2. Between t2 and t3 and between t3 and t4 no statistical differences were found in answers of patients about dissatisfaction, indicating the stability of the results. Conclusions: The ICON resin infiltration technique was found to be effective in lesions resolution with steady results.