Tridimensional surface roughness analysis after resin infiltration of (deproteinized) natural subsurface carious lesions

Influence of different pre-treatments on the resin infiltration depth into enamel of teeth affected by molar-incisor hypomineralization (MIH)

OBJECTIVES

This in vitro pilot study aimed to evaluate whether different pre-treatments (demineralization, deproteinization, (chemo-)mechanical reduction of the surface layer) influence the penetration depth of a resin infiltrant into MIH-affected enamel compared to initial carious lesions.

METHODS

Thirty extracted human permanent molars with non-cavitated initial carious lesions (n = 5) or MIH (n = 25) were chosen and randomly assigned to six experimental groups: IC: initial caries; M: MIH; MN: MIH, 5.25% sodium hypochlorite; MM: MIH, microabrasion; MA: MIH, air abrasion; MAN: MIH, air abrasion and 5.25% sodium hypochlorite. A modified indirect dual fluorescence staining method was adopted to assess the penetration depth (PD) of the resin infiltrant and the lesion depth (LD) by confocal laser scanning microscopy (CLSM). Exemplarily, scanning electron microscopic (SEM) images were captured. The relationship between group assignment and penetration/lesion depth was estimated using a linear mixed model incorporating the tooth as random effect (two observations/tooth). The significance level was set at p < 0.05.

RESULTS

For MIH-affected molars, the mean PD (in µm; median, [minimum-maximum]) were M (178.2 [32.5-748.9]), MN (275.6 [105.3-1131.0]), MM (48.7 [0.0-334.4]), MA (287.7 [239.4-491.7]), and MAN (245.4 [76.1-313.5]). Despite the observed differences in PD between the groups, these could not be statistically verified (Bonferroni, p = 0.322). The percentage penetration was significantly higher for IC than for MIH groups (Bonferroni, p < 0.05).

SIGNIFICANCE

Compared to IC, resin infiltration into MIH-affected enamel ist more variable. Different pre-treatments influence the resin penetration into developmentally hypomineralized enamel to a fluctuating level.

Equivalence study of the resin-dentine interface of internal tunnel restorations when using an enamel infiltrant resin with ethanol-wet dentine bonding

This preregistered ex vivo investigation examined the dentinal hybrid layer formation of a resinous infiltrant (Icon), with reference to both thickness (HLT) and homogeneity when combined with modified tunnel preparation (occlusal cavity only) and internal/external caries infiltration. The adhesives Syntac and Scotchbond MP were used as controls (Groups 1 and 3) or in combination with Icon (Groups 2 and 4). A split-tooth design using healthy third molars from 20 donors resulted in 20 prepared dentine cavities per experimental group. The cavity surfaces (n = 80) were etched (37% H3PO4), rinsed, and air-dried. Rewetting with ethanol was followed by application of the respective primers. After labeling with fluorescent dyes, either Syntac Adhesive/Heliobond or Scotchbond MP Adhesive was used alone or supplemented with Icon. HLT, as evaluated by scanning electron microscopy, did not significantly differ (P > 0.05), and confocal laser scanning microscopy revealed homogeneously mixed/polymerized resin-dentine interdiffusion zones in all groups. Icon can be successfully integrated into an ethanol-wet dentine bonding strategy, and will result in compact and homogeneous hybrid layers of comparable thickness considered equivalent to the non-Icon controls, thus allowing for preservation of the tooth's marginal ridge and interdental space in the case of internal/external infiltration of proximal caries.

Detection of pit and fissure sealant microleakage using quantitative light-induced fluorescence technology: an in vitro study

This in vitro study aimed to evaluate the feasibility of quantitative light-induced fluorescence (QLF) technology for detecting the presence and severity of microleakage of pit and fissure sealants. The areas of interest (AOIs) were 160 pits and fissures of 40 extracted permanent teeth. Fluorescent images were acquired using a QLF device, and the maximum fluorescence loss ΔFmax of each AOI was analyzed. After staining and cross-sectioning of the teeth, histological dye penetration was scored on a scale of 0 to 3. The relationship between ΔFmax and microleakage depth was analyzed, and the areas under the curve (AUCs) were calculated. The │ΔFmax│ increased as microleakage depth increased. The ΔFmax values of microleakage areas showed a strong significant correlation with the histological scores of dye penetration (r = - 0.72, P = 0.001). AUC analysis showed a high diagnostic accuracy for microleakage depth (AUC = 0.83-0.91). The highest AUC of 0.91 was found when differentiating the outer half microleakage of the sealant (histological score 0 vs. 1-3). QLF technology is effective in assessing the presence and severity of microleakage, suggesting its potential for noninvasive detection and monitoring of sealant microleakage in clinical settings.

The Effect of Non-Invasive Treatment Techniques on the Color Masking Ability and Surface Roughness of Induced Enamel Lesions (An in vitro Study)

Aim of the Study

The aim of this in vitro study was to evaluate the effect of the resin infiltration technique and remineralization of induced enamel caries with fluoride solution on the color masking of white spot lesions and surface roughness.

Materials and Methods

A total of 45 sound teeth were used in this study. All the teeth were sectioned along the long axes into two halves, lingual and buccal to get 90 specimens. All specimens were immersed in a demineralized solution for 7 days. The specimens were divided randomly into three equal groups (n = 30) according to the type of treatment; Group 1 (n = 30) was treated with fluoride varnish (Clinpro); Group 2 (n = 30) was treated by resin infiltration (Icon); and Group 3 (n = 30) was used as a control group with no treatment. The color and surface roughness were measured three times at baseline (T1), directly after induction of artificial white spot lesions (WSLs) (T2), and directly after application of the treatment options (T3). The colors were measured using a portable reflective spectrophotometer and the 3D surface roughness was measured using a Light Sectioning Vision System. Data were collected and statistically analyzed using T test and Mann-Whitney U test.

The Results

Surface roughness was almost equal in the study groups with no statistically significant differences reported. Icon showed slightly higher color scores than that of ClinPro.

Conclusions

The Icon produced favorable esthetic results compared to the fluoride therapy while no significant differences were reported regarding the surface roughness.

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.

Short-term Results of the Masking Effect of an Infiltrant Resin on Mild Molar Incisor Hypomineralization Lesions in Anterior Teeth

This non-controlled clinical study evaluated the masking effect of an infiltrant resin on mild molar incisor hypomineralization (MIH) lesions. Thirty MIH-affected anterior teeth with creamy/ white opacities from 12 children aged 6-15 years received the application of an infiltrant resin (Icon- DMG). Standard photographs were taken before (T1), immediately after (T2), and 1 week after (T3) resin infiltration. Two calibrated examiners qualitatively analyzed the color match using the Fédération Dentaire Internationale (FDI) scale. The binomial distribution test analyzed the scores of the color match at T1 with T2 and T3, and McNemar's test analyzed the scores of the color match between T2 and T3 (α=0.05). There was a significant increase in color match between T1 and T2 (p=0.0005), between T1 and T3 (p=0.0005), and between T2 and T3 (p=0.0019). It was concluded that infiltrant resin was effective in improving the esthetic appearance of creamy/white opacities on MIH-affected anterior teeth.

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.

Microhardness and surface roughness of resin infiltrated bleached enamel surface using atomic force microscopy: An in vitro study

to evaluate the microhardness (VHN) and surface roughness (Ra) of human enamel surface treated with resin infiltration followed by in office bleaching and to study the effect of artificial saliva (AS) storage time on the VHN and Ra of resin infiltrated enamel. Materials and methods: Eighty enamel specimens were prepared from extracted human premolar teeth. Specimens were divided into two main groups (I and II) then, they were demineralized to create white spot lesions (WSLs). Group I was divided into A and B sub groups. Group A was treated with in office bleaching material while for group B, resin infiltration (Icon) was applied after 24 h storage in AS followed by bleaching. Group II was divided into (C and D). Group C was treated like group B. Specimens in group D were stored in AS for 14 d after treatment with Icon and before application of bleaching. Atomic force microscopy (AFM) Ra analysis and VHN calculation were done. Independent T Test was used to compare between groups at P < 0.05. Results: Group B demonstrated a significant increase in VHN compared with group A. Storage time in AS showed no significant difference on VHN or Ra between groups. Conclusion: Application of resin infiltration before bleaching significantly increased VHN and slightly improved Ra of WSLs compared with bleaching alone. Application of bleaching material after 24 h or 14 days of the application of resin infiltration did not have a significant effect or surface hardness or roughness of WSLs.

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.

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.

Randomized in situ evaluation of surface polishing protocols on the caries-protective effect of resin Infiltrant

The aim of this placebo-controlled randomized in situ study was to evaluate the effect of different surface polishing protocols on enamel roughness, bacterial adhesion and caries-protective effect of a resin infiltrant. Seventy-five bovine enamel samples having artificial caries lesions were treated with a resinous infiltrant and afterwards randomly dividided into five polishing protocols: aluminum oxide flexible disks (Al₂O₃-Disks), silicon carbide tips (SIC-Tips), silicon carbide brush (SIC-Brush), silicon carbide polyester strips (SIC-Strips) or no polishing [negative control (NC)]. Average surface roughness (Ra) was assessed by profilometry. Samples were mounted in palatal appliances under a mesh for biofilm accumulation. Fifteen volunteers wore the intraoral appliances (14-days) and cariogenic challenge was triggered by sucrose solutions. Biofilm formed was collected for microbiological analysis of caries-related bacteria (Streptococcus mutans, Lactobacillus acidophilus) and demineralization was assessed by cross-sectional microhardness. Mean Knoop hardness numbers (Kg/mm²) were plotted over lesion depth (µm) and area under the lesion curve was subtracted from sound enamel to determine demineralization (ΔS, Kg/mm²xµm). Data were analyzed by ANOVA and post-hoc comparisons (α = 0.05). NC resulted in significantly higher Ra means than Al₂O₃-Disks and SIC-Strips. Bacterial counts were not significantly different between the groups (p > 0.05). Regards ΔS means, however none of the groups were significantly different to NC (6983.3 kg/mm²xµm /CI 4246.1-9720.5, p > 0.05). Conclusions: Polishing protocols (Al₂O₃-Disks, SIC-Strips) significantly decreseased roughness of infiltrated-enamel, however none of the polishing protocols could signicantly decrease bacterial counts nor resulted in significant less demineralization.

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.

The influence of lesion characteristics on application time of an infiltrate applied to MIH lesions on anterior teeth: An exploratory in vivo pilot study

OBJECTIVES

To evaluate the factors that influences the kinetics of resin infiltration of molar incisor hypomineralisation (MIH) lesions on permanent anterior teeth.

METHODS

Demarcated MIH lesions with homogeneous and heterogeneous lesion body appearance, Types 1 (n = 14) and 2 (n = 18), respectively, were selected. After removal of the lesion surface layer using a tapered diamond finishing bur, the lesions were etched and ethanol was applied to the lesions and it was determined if the lesion was still visible or not. Images were taken just prior infiltrant (Icon; DMG) application (T₀), during the infiltration process (T_x) and when infiltration had ceased progressing or opacity disappearance was clinically apparent (T_max). Surface-area measurements of the opacity and infiltrated area were calculated and the infiltration proportion (IP_x) was calculated over the infiltration time.

RESULTS

Type 1 and positive ethanol test lesions showed significantly lower mean T_max (3.4 min) in comparison with Type 2 and negative ethanol test lesions (9.9 min) [Student t-test/Fisher's exact test; p < .01]. A non-linear correlation was observed (R² = 0.88) indicating that the IP_x was rapid at the beginning of resin application, decreasing over time.

CONCLUSION

In comparison with Type 1 and positive ethanol test lesions, Type 2 and negative ethanol test lesions require longer application time to infiltrate.

CLINICAL SIGNIFICANCE

MIH-lesion type and the 'ethanol test' were reliable predictive factors for the application time required for infiltrating MIH lesions on permanent anterior teeth.

Infiltration and sealing for managing non-cavitated proximal lesions: a systematic review and meta-analysis

Background

Infiltration and sealing are micro-invasive treatments for arresting proximal non-cavitated caries lesions; however, their efficacies under different conditions remain unknown. This systematic review and meta-analysis aimed to evaluate the caries-arresting effectiveness of infiltration and sealing and to further analyse their efficacies across different dentition types and caries risk levels.

Methods

Six electronic databases were searched for published literature, and references were manually searched. Split-mouth randomised controlled trials (RCTs) to compare the effectiveness between infiltration/sealing and non-invasive treatments in proximal lesions were included. The primary outcome was obtained from radiographical readings.

Results

In total, 1033 citations were identified, and 17 RCTs (22 articles) were included. Infiltration and sealing reduced the odds of lesion progression (infiltration vs. non-invasive: OR = 0.21, 95% CI 0.15–0.30; sealing vs. placebo: OR = 0.27, 95% CI 0.18–0.42). For both the primary and permanent dentitions, infiltration and sealing were more effective than non-invasive treatments (primary dentition: OR = 0.30, 95% CI 0.20–0.45; permanent dentition: OR = 0.20, 95% CI 0.14–0.28). The overall effects of infiltration and sealing were significantly different from the control effects based on different caries risk levels (OR = 0.20, 95% CI 0.14–0.28). Except for caries risk at moderate levels (moderate risk: OR = 0.32, 95% CI 0.01–8.27), there were significant differences between micro-invasive and non-invasive treatments (low risk: OR = 0.24, 95% CI 0.08–0.72; low to moderate risk: OR = 0.38, 95% CI 0.18–0.81; moderate to high risk: OR = 0.17, 95% CI 0.10–0.29; and high risk: OR = 0.14, 95% CI 0.07–0.28). Except for caries risk at moderate levels (moderate risk: OR = 0.32, 95% CI 0.01–8.27), infiltration was superior (low risk: OR = 0.24, 95% CI 0.08–0.72; low to moderate risk: OR = 0.38, 95% CI 0.18–0.81; moderate to high risk: OR = 0.20, 95% CI 0.10–0.39; and high risk: OR = 0.14, 95% CI 0.05–0.37).

Conclusion

Infiltration and sealing were more efficacious than non-invasive treatments for halting non-cavitated proximal lesions.

Colour and chemical stability of bismuth oxide in dental materials with solutions used in routine clinical practice

Bismuth(III) oxide is included as a radio-opacifier in dental materials, including hydraulic silicate cements, the material of choice for several endodontic procedures. It has been implicated in tooth discoloration after contact with endodontic irrigants, in particular NaOCl solution, To date, there has been no work on the chemistry: all reports have been of clinical findings only. The purpose now was to report the reactions leading to colour change from Bi2O3 in contact with solutions used in routine endodontic practice. Ten-gram portions of Bi2O3 were immersed in either water, NaOH, NaCl, NaOCl or HCl solution, either in the dark or exposed to visible light, and samples retrieved at 1, 4, 12 and 24 weeks. After washing, these were exposed to either added CO2 or not, for 1 week while drying, and under the same dark or light conditions. Changes in appearance were monitored by photography and colour measurement, and chemically by X-ray diffraction and Fourier-transform infrared spectroscopy. 24-week material was studied using electron paramagnetic resonance and Raman spectroscopy; NaOCl-treated material was also examined by scanning electron microscopy. With water, NaCl and NaOH, bismuth subcarbonate was formed. With or without added carbon dioxide, discoloration occurred from pale yellow to light brown when exposed to light, and to a lesser extent in the dark, intensifying with time. In contrast, exposure to NaOCl rapidly formed a dark brown-black sodium bismuthate. With HCl, white BiOCl was formed. Bi2O3 is not at all inert in this context as is commonly believed, denying its principle of use. Previously unreported solution-mediated reaction occurs readily even in water and NaCl solution, forming new compounds that discolour. In contact with NaOCl sodium bismuthate is formed; severe darkening occurs rapidly. The reactivity is such that Bi2O3 is not indicated for dental materials and should be withdrawn from use.

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.

Effect of resin infiltration application on early proximal caries lesions in vitro

Background/purpose

Resin infiltration (RI) material ICON is used in treating early proximal caries lesions, as it depends on a micro-invasive infiltration technology. This in vitro study aimed to evaluate the effect of ICON resin infiltration (RI) on early proximal caries by comparing surface roughness and hardness before and after treatment with RI using atomic force microscopy (AFM), automated microhardness testing system (AMHTS), and scanning electron microscopy (SEM) in vitro.

Materials and methods

Twenty seven premolars extracted for orthodontic reasons were sectioned buccolingually, creating 54 specimens. Each specimen was immersed in demineralizing solution to induce caries. Only teeth with "International Caries Detection and Assessment System" codes 1 and 2 were selected. The specimens were divided randomly into either AFM, AMHTS or SEM groups, which examined demineralized enamel before and after treatment with ICON.

Results

The mean average surface roughness and root mean square roughness values of demineralized enamel treated with ICON were significantly higher than untreated lesions (P < 0.001). The mean Vickers hardness values for demineralized enamel treated with ICON was significantly higher than untreated lesions (P < 0.001). SEM showed irregular, pitted and rough demineralized enamel surface with destruction of enamel rods and dissolution of enamel crystals. After ICON application, the surface showed complete blockage of enamel rods with RI and irregular, rough uneven topography.

Conclusion

RI application on proximal incipient caries increased surface roughness and hardness significantly.

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.

The Use of Resinous Infiltrants for the Management of Incipient Carious Lesions: a Literature Review

AbstractThe objective of this work was to analyze scientific evidence from a literature review pertaining to the effectiveness of resinous infiltrants for minimally invasive treatment of incipient carious lesions. Studies published between 2002 and 2019 were queried from the following databases: Capes, PubMed, Medline, BBO, Lilacs and SciELO. The search keywords included "Dental Caries", "Tooth Remineralization", "Dental Leakage". Most of the studies found resin-infiltrating treatment to be a viable option for the minimally invasive treatment of incipient carious lesions; this treatment was able to fulfill the primary expected effects: inhibition of carious progression and the lesions esthetic improvement. However, some issues need to be clarified to improve the safety of this treatment because it can be recommended in clinical practice. In conclusion, the use of resinous infiltrants has been reported as promising for the treatment of incipient carious lesions. However, there is a need for long-term studies to confirm the effectiveness of this treatment to determine its applicability for clinical use. Keywords: Dental Caries. Dental Leakage. Tooth Remineralization. ResumoO objetivo desse trabalho foi analisar evidências científicas, por meio de uma revisão de literatura, sobre a eficácia do uso de infiltrantes resinosos para o tratamento minimamente invasivo de lesões cariosas incipientes. A seleção do material literário utilizado foi realizada por pesquisa sobre o tema nas bases de dados: portal de periódicos Capes, PubMed, Medline, BBO, Lilacs e SciELO, abrangendo prioritariamente, o período de 2002 a 2019. Para busca nas bases de dados foram utilizadas palavras-chave como “Cárie Dentária”, “Remineralização Dentária”, “Infiltração Dentária”, assim como suas correspondentes na língua inglesa.  A maioria dos estudos encontrados aponta o tratamento infiltrante resinoso como uma opção viável para o tratamento minimamente invasivo de lesões cariosas incipientes sendo capaz de cumprir os principais efeitos esperados: inibição da progressão cariosa e melhoria estética das lesões. Entretanto, alguns impasses necessitam ser esclarecidos para que o tratamento seja recomendado com mais segurança na prática clínica. Conclui-se que o uso de infiltrantes resinosos tem sido relatado como promissor para o tratamento de lesões cariosas incipientes, contudo há necessidade de novas pesquisas e estudos a longo prazo para confirmar sua eficácia em todos aspectos desejáveis para seu uso clínico. Palavras-chave: Cárie Dentária. Infiltração Dentária. Remineralização Dentária.

[Evaluation of the color stability of infiltrant resin in comparison to aesthetic composite resins]

OBJECTIVE

To investigate the color stability of infiltrant resin together with three other composites exposed to staining solution.

METHODS

Three types of anterior aesthetic composite resins (Filtek Z250, Filtek Z350 XT, and Beautiful Flow Plus F00) and artificial caries with Icon infiltrant resin were used. The samples were randomly divided into two groups (each contained 10 specimens): coffee solution and distilled water immersion for three weeks. Color parameters were deter-mined with the Crystaleye spectrophotometer.

RESULTS

Artificial caries lesions infiltrated by Icon showed much higher ΔE than those infiltrated by other aesthetic resins (P<0.05). The discoloration of all the experimental resins and the artificial caries infil-trated with Icon increased with time, but the discoloration on the 1st week was significantly higher than those on the 2nd and 3rd weeks.

CONCLUSIONS

Artificial caries infiltrated with Icon was more vulnerable and susceptive to food color than those infiltrated with other aesthetic composite resins.

Power bleaching enhances resin infiltration masking effect of dental fluorosis. A randomized clinical trial

OBJECTIVES

Patients with moderate dental fluorosis often feel esthetically compromised. Aim of this RCT was to evaluate the objectively and self-assessed masking effect of resin infiltration alone or in combination with in-office bleaching on dental fluorosis in adults.

METHODS

Twenty-seven patients (9 male, 18 female, 24.81 ± 3.7 yrs) with 410 fluorotic teeth (TF 1-4) were randomly assigned to a treatment (BLI) or control group (NBLI). Patients underwent in-office bleaching (25% H₂O₂) in the BLI or a placebo bleaching (ACP gel) in the NBLI group followed by resin infiltration after two weeks. Standardized digital photographs were obtained at baseline; after bleaching; before and after resin infiltration and after 1, 3, and 6 months. Color differences (ΔE) between sound and fluorotic areas were calculated and patient satisfaction was evaluated using a VAS (1-10).

RESULTS

Statistical analysis revealed significant differences in the mean ΔE values 6 months after resin infiltration between the BLI (ΔE = 1.41) and the NBLI group (ΔE = 4.33) (p = 0.024). VAS values increased after resin infiltration (p < 0.05) in both groups. After 3 months patients in the BLI group had higher VAS values than in the NBLI group (p = 0.029).

CONCLUSIONS

Findings of this study suggest that resin infiltration alone can effectively mask mild to moderate dental fluorosis in young adults. In-office bleaching with 25% H₂O₂ before resin infiltration provides significantly better masking effects.

CLINICAL SIGNIFICANCE

Resin infiltration is a safe and efficient treatment option for masking fluorotic opacities. A priori in-office bleaching with 25% H₂O₂ enhances the masking effect. This controlled clinical trial is registered in the German Clinical Trials Register #DRKS00010465.

Minimally Invasive Approach for Improving Anterior Dental Aesthetics: Case Report with 1-Year Follow-Up

Dental aesthetics have become highly important in recent years. Treating aesthetic demands with noninvasive or minimally invasive techniques can preserve the natural tissues. A 20-year-old female patient presented to the clinic with aesthetic concerns. After the clinical and radiographic examinations, hypomineralization was identified in the maxillary anterior teeth except the maxillary right canine. An external discoloration was also identified in the maxillary left canine tooth. Moreover, the right canine tooth was identified as a Turner's tooth according to the patient's anamnesis. The resin infiltration technique was applied to the maxillary anterior teeth except the maxillary right canine. The bleaching treatment was applied to the maxillary left canine tooth. Then, a laminate veneer restoration was applied to the upper right canine tooth with Turner's hypoplasia. Following the treatment, a satisfactory aesthetic restoration was achieved. After 1-year examination, no clinical failures were observed.

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.

Modified resin infiltration of non-, micro- and cavitated proximal caries lesions in vitro

OBJECTIVE

Infiltrant resin (IR) is currently indicated for non-cavitated caries lesions. However, modifying the technique might expand its indication spectrum to micro-cavitated lesions. The present study aimed to evaluate the penetration/filling ability of a newly developed micro-filled infiltrant resin (MFIR) in non-, micro- and cavitated natural caries lesions.

MATERIALS AND METHODS

Proximal lesions in 120 extracted human teeth with ICDAS-2 (n = 30), 3 (n = 45) and 5 (n = 45) lesions were etched with 15% hydrochloric acid gel for 2 min and allocated to one of the following treatments; IR: lesions (ICDAS-2, 3 and 5; each n = 15) were treated with commercial infiltrant resin for 3 min. MFIR: experimental MFIR [55 wt% IR plus 45 wt% organic fillers] was applied to lesions (ICDAS-2, 3 and 5; each n = 15) for 3 min. IR + FC: IR was applied for 3 min, light-cured, and cavities (ICDAS-3 and 5; each n = 15) filled with flowable composite (FC). Percentage infiltration of the demineralized enamel (Inf.%) and percentage filling of the cavity (Fill.%) were analyzed using dual-fluorescence staining and confocal microscopy.

RESULTS

No significant differences in Inf.% (range of medians: 57%-100%) were observed between different treatments (p > 0.05; Kruskal-Wallis) within each ICDAS-code. Fill.% of cavities was significantly higher in groups MFIR (median in ICDAS-3/-5: 100%/100%) and IR + FC (100%/100%) than IR (25%/38%) (p < 0.05).

CONCLUSION

MFIR showed similar penetration into natural lesions as the commercial infiltrant, but better ability to fill cavitated areas.

CLINICAL RELEVANCE

MFIR and IR + FC might provide a new micro-invasive treatment for small cavitated proximal lesions.

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.

Resin infiltration of deproteinised natural occlusal subsurface lesions improves initial quality of fissure sealing

The aim of this ex vivo study was to evaluate the infiltration capability and rate of microleakage of a low-viscous resin infiltrant combined with a flowable composite resin (RI/CR) when used with deproteinised and etched occlusal subsurface lesions (International Caries Detection and Assessment System code 2). This combined treatment procedure was compared with the exclusive use of flowable composite resin (CR) for fissure sealing. Twenty premolars and 20 molars revealing non-cavitated occlusal carious lesions were randomly divided into two groups and were meticulously cleaned and deproteinised using NaOCl (2%). After etching with HCl (15%), 10 premolar and 10 molar lesions were infiltrated (Icon/DMG; rhodamine B isothiocyanate (RITC)-labelled) followed by fissure sealing (G-ænial Flo/GC; experimental group, RI/CR). In the control group (CR), the carious fissures were only sealed. Specimens were cut perpendicular to the occlusal surface and through the area of the highest demineralisation (DIAGNOdent pen, KaVo). Using confocal laser-scanning microscopy, the specimens were assessed with regard to the percentage of caries infiltration, marginal adaption and internal integrity. Within the CR group, the carious lesions were not infiltrated. Both premolar (57.9%±23.1%) and molar lesions (35.3%±22.1%) of the RI/CR group were uniformly infiltrated to a substantial extent, albeit with significant differences (P=0.034). Moreover, microleakage (n=1) and the occurrence of voids (n=2) were reduced in the RI/CR group compared with the CR group (5 and 17 specimens, respectively). The RI/CR approach increases the initial quality of fissure sealing and is recommended for the clinical control of occlusal caries.

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 Roughness of Initial Enamel Caries Lesions in Human Teeth After Resin Infiltration

BACKGROUND

Low viscosity resin infiltration of initial caries lesions is a modern microinvasive method to treat initial cries lesions. However, only scarce information is available about the long-term surface alterations of infiltrated lesions.

METHODS

Twenty-eight premolar teeth exhibiting non-cavitated initial caries lesions (International Caries Detection and Assessment System (ICDAS code 1&2)) were divided into two groups, one of which was infiltrated with resin, and the other remained untreated. The teeth underwent two thermocycling procedures. The surface roughness was determined quantitatively, and the results were evaluated statistically. In addition, the surfaces of the lesions were investigated by scanning electron microscopy (SEM), and the surface was analyzed visually with respect to surface irregularities.

RESULTS

The results showed a reduction in the surface roughness that was significant after 2500 thermocycles compared to the untreated surface. In the control specimens, no change in the surface roughness was found. The qualitative SEM data also showed a smooth surface after thermocycling, which supported the statistical findings.

CONCLUSION

After thermocycling, resin-infiltrated enamel surfaces become smoother and had no additional risk for plaque accumulation.