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

Effect of Extent of White Spot Lesions on the Esthetic Outcome after Treatment by the Resin Infiltration Technique: A Clinical Trial

Objectives: This study aimed to assess the effect of extent of white spot lesions (WSLs) on the esthetic outcome (masking effect and durability) for 6 months after treatment by the resin infiltration technique. Materials and Methods: In this clinical trial, 79 teeth with WSLs in 18 patients were selected. The lesions were assigned to localized and generalized groups, and were all treated by resin infiltration. The color of WSLs was assessed at baseline, immediately after treatment, and 1, 3, and 6 months after treatment by using Easy Shade spectrophotometer and taking standard digital photographs. The surface area of WSLs was calculated on the photographs using MIP4Student software. Repeated Measures ANOVA was used to compare color change (∆E), and the Pearson's correlation test was applied to analyze the association between the extent of lesions and ∆E (alpha=0.05). Results: A significant difference was found between the two groups in ∆E at different time points (P<0.05). Also, in both localized and generalized lesions, the pretreatment ∆E was significantly different from the ∆E values at different time points after treatment (P<0.001). However, the post-treatment ∆E values were not significantly different (P>0.05). The Pearson test showed an inverse correlation between the extent of lesions and ∆E (P<0.05). Conclusion: The resin infiltration technique is successful in masking the WSLs, with a durability of at least 6 months. Color correction by this technique is more favorable in localized lesions.

Theobromine versus casein phospho-peptides/Amorphous calcium phosphate with fluoride as remineralizing agents: effect on resin-dentine bond strength, microhardness, and morphology of dentine

BACKGROUND

This study aimed to assess the impact of theobromine and casein phospho-peptides/amorphous calcium phosphate with fluoride (CPP-ACPF) on the resin-dentine bond strength, microhardness, and dentine morphology.

METHODS

A total of 18 sound human molars for micro-tensile bond strength (µTBS), 20 sound human premolars for microhardness, and 30 premolars for Scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX) were used. Based on the pre-treatment used, teeth were split into six groups; sound dentine, demineralized dentine, and demineralized dentine treated with theobromine (Sigma Aldrich) and MI paste plus (GC International, USA) for two-time intervals; 5 min and 1 month. The bonded teeth were sectioned to produce 1 mm² resin-dentine sticks which were evaluated for µTBS using a universal testing device (Instron 3365, USA). The dentine microhardness was tested by using the Vickers microhardness tester (Nexus 4000 TM, Netherlands). The pre-treated dentine surface was examined using SEM/EDX (Neoscope JCM-6000 plus Joel benchtop SEM, Japan). µTBS results were analysed with two-way ANOVA. Microhardness and EDX results were analysed with two-way mixed model ANOVA. The significance level was set at (p ≤ 0.05).

RESULTS

While both remineralizing materials at the two-time intervals demonstrated µTBS comparable to sound dentine (46.38 ± 12.18), the demineralized group demonstrated statistically the lowest µTBS (p < 0.001). Whether used for 5 min or 1 month, theobromine significantly increased the microhardness (50.18 ± 3.43) and (54.12 ± 2.66) respectively (p < 0.001), whereas MI paste only increased the hardness (51.12 ± 1.45) after 1 month (p < 0.001).

CONCLUSIONS

The pre-treatment of demineralized dentine with theobromine for 5 min or 1 month could enhance its bond strength and microhardness while for MI paste plus, only 1-month application was efficient to ensure remineralization.

Theobromine versus Casein phospho-peptide/Amorphous Calcium Phosphate with Fluoride as remineralizing agents: Effect on resin-dentine bond strength, microhardness, and morphology of dentine.. [DOI: 10.21203/rs.3.rs-2722167/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Background: This study aimed to assess the impact of theobromine and casein phospho-peptides/amorphous calcium phosphate with Fluoride (CPP/ACPF) on the resin-dentine bond strength, microhardness, and dentine morphology. Methods: Based on the pre-treatment used, 18 sound human third molars were split into six groups.; sound dentine, demineralized dentine, and demineralized dentine treated with theobromine and MI paste plus for two-time intervals; 5 minutes and 1 month. The bonded teeth were sectioned to produce 1 mm2 resin-dentine sticks which were evaluated for micro-tensile bond strength (µTBS) using a universal testing device. The dentine microhardness was tested by using the Vickers microhardness tester. The pre-treated dentine surface was examined using Scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX). µTBS results were analysed with two-way ANOVA. Microhardness and EDX results were analysed with two-way mixed model ANOVA. Results: While both remineralizing materials at the two-time intervals demonstrated µTBS comparable to sound dentine, the demineralized group demonstrated statistically the lowest µTBS. Whether used for 5 minutes or 1 month, theobromine significantly increased the microhardness, whereas MI paste only increased the hardness after 1 month. Conclusions: The pre-treatment of demineralized dentine with theobromine and MI paste plus could enhance its bond strength and microhardness.

The Effect of Aloe vera and Chlorhexidine as Disinfectants on the Success of Selective Caries Removal Technique: A Randomized Controlled Trial

This study aimed to evaluate the effect of Aloe vera and chlorhexidine "CHX" as disinfectants on the success of selective caries removal technique in deep carious lesions. A total of 60 patients with: (I) deep class II carious lesion diagnosed with reversible pulpitis; (II) good oral hygiene; (III) no gingival recession or periodontal diseases; (IV) no antibiotic or antifungal treatment in the last three months; and (V) no systematic disease or pregnancy were included in the study. Sixty patients were distributed randomly to three experimental groups (n = 20): Group 1: no disinfectant solution was applied (control group); group 2: the cavity was filled with 2% CHX for 5 mins and then dried with a sterilized cotton pellet; group 3: the cavity was filled with Aloe vera extract for 5 mins and then dried with sterilized cotton pellet. One week later, only teeth with vital pulp characteristics were restored definitely with resin composite. After 18 months, clinical and radiographic examination was performed by using a blinded separated evaluator. The data were tabulated and analyzed using the chi-square test by SPSS 13.0 with a significance level (p ≤ 0.05). It was observed that 13 teeth of the control group, 14 teeth of the CHX group, and 16 teeth of the Aloe vera group were diagnosed with healthy vital pulp after 18 months. There was no significant difference between the CHX and the control group; however, there was a significant difference between the Aloe vera and control group (p ≤ 0.007). Aloe vera extract as a cavity disinfectant increases the success rate of selective caries removal technique of deep carious lesions.

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.

The Effect of Er:YAG Laser on a Shear Bond Strength Value of Orthodontic Brackets to Enamel-A Preliminary Study

We sought to evaluate the effects of Er:YAG laser (LightTouch, LightInstruments, Israel) conditioning on enamel roughness and shear bond strength of orthodontic brackets on enamel. Eighteen human molars (n = 9) and premolars (n = 9), were divided into 3 groups depending on the enamel conditioning method; Er:YAG laser (G1, n = 6), conventional etching with 37% orthophosphoric acid (G2, n = 6), Er:YAG laser combined with conventional etching (G3, n = 6). Er:YAG laser parameters were as follows: energy: 100 mJ, frequency: 10 Hz, exposure time: 10 s, applicator diameter: 600 μm, fluence: 35.37 J/cm², distance: 1 mm away from a tooth, cooling: 80%. An MTS 858 MiniBionix^® machine was used to determine the shear bond strength (MTS System, Eden Prairie, MN, USA). The enamel structure was assessed using X-ray microtomography (SkyScan 1172, Bruker, Kontich, Belgium). The highest values of shear bond strength were obtained in the G3 group (9.23 ± 2.38 MPa) and the lowest values in the G2 group (6.44 ± 2.11 MPa) (p < 0.05). A significant change in the enamel surface was noted after applying laser, reaching up to 9% of enamel thickness, which was not observed in the etched samples. Moreover, the Er:YAG laser-irradiated enamel surface was characterized by the greatest roughness. The combined use of an Er:YAG laser with a conventional etching improves the adhesion of composite materials to the tooth.

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.