Evaluation of a novel approach in the prevention of white spot lesions around orthodontic brackets

A Comparative In Vitro Physicochemical Analysis of Resin Infiltrants Doped With Bioactive Glasses

Objective This study aimed to investigate the longevity and effectiveness of bioactive glass (BAG)-based dental resin infiltrants. Materials and methods The three types of BAG - 45S5 bioglass (RIS), boron-substituted (RIB), and fluoride-substituted (RIF) - were incorporated with photoinitiated dimethacrylate monomers to create experimental resin infiltrants. ICON® (CN; DMG-America, Ridgefield Park, NJ) and pure resin (PR) were used as control groups in this study. Disc-shaped samples were prepared for the experimental and control groups. The samples were challenged with the pH cycle and immersed in the artificial saliva for 30 days. On Day 0 and Day 30, the pH cycle and artificial saliva immersion, Vicker's microhardness, surface roughness, and surface morphology were investigated. Results The RIF group's disc samples showed the highest Vicker's microhardness values (78.20 ±0.06) on Day 30 of artificial saliva immersion, whereas the CN group's values were the lowest (55.99 ±0.24). Following the pH cycling, the RIF displayed the highest hardness (64.15 ±1.89) whereas the CN group's values were the lowest (33.47 ±1.28). Regarding surface roughness, on Day 30, the RIB resin group exhibited the highest (1.14 ±0.001 µm). In contrast, the CN resin showed the lowest (1.07 ±0.06 µm) values, while immersed in the artificial saliva solution. In the same duration of time, in the pH cycling solution, PR showed the least (0.85 ±0.89 µm), while RIF showed the highest roughness value (0.94 ±0.54 µm). Morphological analysis revealed that following the artificial saliva immersion, the RIB, CN, and PR exhibited smoother surfaces compared to the RIS and RIF groups. However, when immersed in the pH cycling solution, RIB and RIF showed more resistance against acid attack. Conclusions Our results revealed that the experimental resin groups performed much better than the commercial resin infiltrants following artificial saliva and pH cycling challenges.

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.

Resin infiltration in white spot lesions caused by orthodontic hypomineralisation: a minimally invasive therapy

Objective White spot lesions are characterised by the presence of clinically detectable opaque lesions due to enamel demineralisation. These frequently present in patients following fixed orthodontic treatment, mostly due to the prolonged accumulation of bacterial plaque on the dental surface. When remineralisation is not achieved through good oral hygiene and prophylaxis with fluoride products, the infiltration of lesions with low-viscosity photopolymerised resin has proved to be a valid micro-invasive alternative compared to traditional conservative therapy.Clinical considerations A case series will be presented, where the chosen approach was resin infiltration, a micro-invasive and aesthetic technique.Clinical significance Infiltrative resin therapies are single-session procedures that reduce the need for more invasive therapies such as the use of rotary instruments for greater patient comfort. The need for periodic fluoride applications is also avoided. This approach increases the durability of the infiltrated lesion without compromising its mechanical properties and impedes the development of recurrent or secondary caries.Conclusions Resin infiltration might be considered as a routine procedure in the treatment of post-eruptive hypomineralised lesions. This follows the line of thought of minimally invasive dentistry, is an excellent treatment option and prevents the lesion's progression.

A comparison of resin infiltration and microabrasion for postorthodontic white spot lesion

INTRODUCTION

The objective of this research was to evaluate and compare the effectiveness of microabrasion and resin infiltration for white spot lesions (WSLs).

METHODS

Patients with postorthodontic WSLs were enrolled and randomly assigned to the control, microabrasion, and resin-infiltration groups. Intraoral photographs were taken before and after (6 months later) treatment. WSL sizes were determined through ImageJ (Wayne Rasband, Kensington, Md). Integrated optical density (IOD) was determined for a WSL and its surrounding normal enamel through Image-Pro Plus (version 6.0; Media Cybernetics, Rockville, Md), and their differences of IOD were considered as the IOD surrogate for that WSL. The color change of WSL were measured through ΔE.

RESULTS

A total of 27 eligible patients were enrolled; 9 subjects were assigned to each group, resulting in 56 teeth in the control group, 72 in the microabrasion group, and 58 in the resin-infiltration group. The ratios of WSL size (after/before) were similar between the microabrasion and resin-infiltration group (43.94 ± 0.03% vs 45.02 ± 0.03%; P = 0.96 > 0.05), but those of the 2 groups were significantly lower than those of the control group (92.15 ± 0.02%) (P <0.001). Moreover, the ratios of IOD (after/before) were significantly lower in the resin-infiltration group (22.94 ± 0.02%) than in the microabrasion (78.11 ± 0.03%) and control (83.79 ± 0.02%) (P <0.001) groups. The highest ΔE improvement was obtained by infiltration, but there was no significant difference between microabrasion and control group.

CONCLUSIONS

Resin infiltration and microabrasion are comparably effective in reducing the sizes of WSL, but resin infiltration enjoys an esthetic advantage over microabrasion.

Acid Resistance of Glass Ionomer Cement Restorative Materials

In view of the need for aesthetics, restorations of teeth will typically be completed using tooth colored restorative materials. With the advent of biomimetic restorative materials, such as glass ionomer cements (GIC), much greater emphasis is now being placed on how well such materials can resist the challenge of acids that are present in foods and drinks, or gastric contents that are regurgitated. This laboratory study compared the dissolution and behavior of five GIC materials (GC Fuji® VII, GC Fuji® Bulk, GC Fuji® IX Fast, Fuji® IX Extra and GC Equia® Forte Fil) when exposed to three acids (citric acid, phosphoric acid and lactic acid), versus ultrapure deionized water, which was used as a control. Discs of each material GIC were submerged in solutions and percentage weight changes over time determined. Subsequently, the GIC materials were also placed as a part of standardized Class II sandwich restorations in bovine teeth (n = 20), and submerged in the solutions, and the extent of GIC dissolution and protection of the adjacent tooth was scored. Weight loss increased with time and with acid concentration. Overall, the most soluble material was GC Fuji® IX Extra, while GC Fuji® IX Fast and GC Fuji® Bulk were less soluble, and the least soluble material was GC Equia® Forte Fil. The most destructive solution for both the discs and for GIC restorations in teeth was 10% citric acid, while the least destructive acid was 0.1% lactic acid. The more recent GIC materials GC Fuji® Bulk and GC Equia® Forte Fil showed increased acid resistance over the older GIC materials, and this further justifies their use in open sandwich Class II restorations in more hostile environments.

Casein phosphopeptide-amorphous calcium phosphate modified glass ionomer cement attenuates demineralization and modulates biofilm composition in dental caries

The study investigated the effects of the modified conventional glass ionomer cement (GIC) incorporated with casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on biofilm composition of dental caries. Shear bond strength, durability tests, adhesive remnant index (ARI) and scanning electron microscope were used to measure the physical properties. Microhardness and ions release were determined to evaluate anti-demineralization effects; growth of the biofilm and its composition were assessed using MTT assay and Q-PCR assay. All experimental groups exhibited a significant stimulation of ions release, and reduced attenuation of microhardness. Nearly 39% reduction in the bacterial biofilm was observed with 5% CPP-ACP group. The regulation ability is mainly manifested in the inhibition of S. mutans and promotion of S. gordonii. The modified GICs by exhibiting anti-demineralization effects potentially lead to a reduction in the cariogenicity of plaque and can serve as a putative promising remineralization system with both enhanced antimicrobial and remineralization properties.

Monitoring enamel caries on resin-treated occlusal surfaces using quantitative light-induced fluorescence: an in vitro study

The aim of this study is to evaluate the ability of quantitative light-induced fluorescence (QLF) to monitor enamel caries lesions of different severity stages located on the occlusal surfaces of permanent teeth before and after treatment with resin infiltrant. Sixty extracted permanent teeth had one occlusal site selected and were categorized according to the International Caries Detection and Assessment System (ICDAS) criteria. The teeth were divided into three groups (n = 20): ICDAS 1, ICDAS 2, and ICDAS 3. The teeth were assessed by a trained examiner using QLF in two phases: (A) before and (B) after treatment with resin infiltrant. The caries lesions were evaluated using the following QLF parameters: area (mm²); ΔF, fluorescence loss (%); and ΔQ, fluorescence loss integrated over the lesion area (%*mm²). The resin infiltrant (Icon™) was applied on the occlusal surface following the manufacturer's recommendations. The teeth were then sectioned and prepared for polarized light microscopy analysis. The penetration of resin infiltrant was measured with ImageJ. The groups showed a statistically significant difference in all QLF parameters before and after caries infiltration, with the reduction of fluorescence values posttreatment (p < 0.05). Infiltrant penetration was observed in all groups, with a statistical difference between all groups (p < 0.05). The reduction in QLF parameters after resin infiltration suggests that QLF is able to monitor enamel caries lesions of different severity stages located on the occlusal surfaces of permanent teeth before and after treatment with resin infiltrant.

Evaluation of the efficacy of casein phosphopeptide-amorphous calcium phosphate on remineralization of white spot lesions in vitro and clinical research: a systematic review and meta-analysis

BACKGROUND

This systematic review with meta-analyses sought to answer whether casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) provided a remineralizing benefit superior to that of nonintervention or placebo.

METHODS

Following Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines, Cochrane databases, PubMed, EmBase, and Ovid up to May 20th, 2019, were scanned, only published in English. Study information extraction and methodological quality assessments were accomplished independently by two reviewers. The "Criteria for judging risk of bias in the 'Risk of bias' assessment tool" was used for methodological quality assessment. The continuous data was analyzed by mean difference (MD) or standardized mean difference (SMD) with a 95% confidence interval (CI). Review Manager 5.3 was used for statistical analysis. Outcome variables include quantitative light-induced fluorescence in clinical research, average surface roughness and surface microhardness in vitro.

RESULTS

There were significant differences in the quantitative light-induced fluorescence (SMD = - 0.43, 95% CI: [- 0.79, - 0.07], P = 0.02), average surface roughness (SMD = - 8.21, 95% CI: [- 10.37, - 6.04], P < 0.01), Vickers microhardness (SMD = 1.19, 95% CI: [0.72, 1.66], P < 0.01), and Knoop microhardness (SMD = 3.52, 95% CI: [2.68, 4.36], P < 0.01) between the CPP-ACP and control groups or baseline.

CONCLUSION

Within the limitations of this meta-analysis, CPP-ACP exhibited excellent remineralization effects evaluated in clinical research and in vitro, indicating outstanding restoration of form, aesthetics, and function in treating white spot lesions.

Prevention of white spot lesions using three remineralizing agents: An in vitro comparative study

Background. Enamel demineralization around orthodontic brackets is an important clinical problem. This study sought to compare the efficacy of sodium fluoride (NaF), casein phosphopeptide amorphous calcium phosphate fluoride (CPP-ACP-F; MI Paste Plus) and a water-based cream (Remin Pro), which contains hydroxyapatite and fluoride for prevention of enamel demineralization.

Methods. Fifty-six sound human premolars extracted for orthodontic purposes were collected. After cleaning, the crowns were mounted in acrylic resin and all the surfaces were coated with nail varnish except for a 3×4-mm window on the buccal surface. The samples were randomly divided into four groups of 14 and subjected to pH cycling for 14 days, during which the teeth were immersed in artificial saliva for 21 hours and in demineralizing agent for three hours daily. Before transferring the samples from the saliva to the demineralizing solution, the remineralizing agent (0.05% NaF, MI Paste Plus or Remin Pro Paste, depending on the group) was applied on the samples once a day for five minutes. No remineralizing agent was used in the control group. Surface microhardness of samples was measured by Vickers microhardness tester at baseline and after the intervention. The data were analyzed using one-way ANOVA, ANCOVA, Bonferroni test and Tukey test. Statistical significance was set at P<0.05.

Results. The mean microhardness was significantly different between the test and control groups (P<0.0001). Other differences were not significantly different (P>0.05).

Conclusion. The results showed that 0.05% NaF was more efficient than Remin Pro and MI Paste Plus for prevention of white spot lesions (WSLs). Remin Pro and MI Paste Plus were not significantly difference from the control group in this regard.

Enamel demineralization around metal and ceramic brackets: an in vitro study

Aim

To evaluate the degree of enamel demineralization of teeth bonded with ceramic and metal brackets.

Materials and methods

In this cross-sectional experimental in vitro study, 60 extracted human premolar teeth were selected according to the experimental criteria. They were divided into three groups; 20 premolar teeth in each group. Teeth in group 1 were bonded with "ceramic brackets", and teeth in group 2 were bonded with "metal brackets", while teeth in group 3 served as the "control group" without any brackets. Teeth in all groups were then immersed in demineralization media, de-bonded, sectioned into three parts (proximal 1, middle, and proximal 2), and evaluated to determine the level of enamel demineralization under a Scanning Electron Microscope.

Results

On tooth level, the results show that the control group has significantly less enamel demineralization compared to the other two experimental groups, with mean values of 145.3 µm and 192.7 µm, respectively (P=0.000). The mean value of enamel demineralization in the metal group is 55.93 µm, compared to 72.55 µm in the ceramic group, which is significantly less (P≤0.05), while there is no difference between the control and metal group with regard to enamel demineralization. On section level, the control group has significantly less enamel demineralization in all three sections compared to the ceramic group, while a significant difference is found in one of the proximal sections when compared with the metal group. Moreover, the ceramic group has significantly higher enamel demineralization in the middle section compared to the metal group (73.54 µm, 46.5 µm, respectively) (P=0.000), while there is no statistical significant difference between the two experimental groups in proximal sections.

Conclusion

In vitro, non-bonded teeth show least demineralization compared to the bonded teeth. Teeth bonded with ceramic brackets show significantly higher enamel demineralization compared to teeth bonded with metal brackets.

Effects of staining and polishing on different types of enamel surface sealants

OBJECTIVE

To assess surface discoloration of four enamel sealants based on different chemical compositions after exposure to artificial aging and staining solutions. Furthermore, their cleanability after polishing will be evaluated.

MATERIALS AND METHODS

Selected sealants were a composite resin-based sealant with fillers (Pro Seal), a composite resin-based sealant without fillers (Light BondSealant), a resin-modified glass ionomer-based sealant (ClinproXT Varnish) and a silicon-based sealant (Protecto). Natural teeth served as medium. Immersion solutions were water, juice, tea, and turmeric. In a standardized setting, all samples were measured seven times with a spectroradiometer (Photoresearch PR670) at baseline, after thermocycling; 7 days; 2 and 4 weeks of immersion; and after finally polishing.

RESULTS

Thermocycling had no significant effect on color stability. After exposure to staining solutions, all sealed surfaces showed significant color changes. Color change predominately occurred for all sealants in the first week of staining (P ≤ .01). Best resistance to staining decreased as follows: Protecto > Light Bond Sealant > ProSeal > Clinpro XT Varnish. Surface cleaning by polishing significantly reduced the color change.

CONCLUSION

Sealed enamel surfaces are prone to discoloration, which is most prominent in filled composite and glass-ionomer-based sealants. Staining can be reduced by polishing; however, in this in vitro setting the original color could not be restored.

CLINICAL SIGNIFICANCE

Enamel sealants might exert adverse effects in terms of discoloration. This should be taken into consideration by clinicians and patients, particularly when sealants are applied in esthetically critical areas.

Biodegradable Materials and Metallic Implants-A Review

Recent progress made in biomaterials and their clinical applications is well known. In the last five decades, great advances have been made in the field of biomaterials, including ceramics, glasses, polymers, composites, glass-ceramics and metal alloys. A variety of bioimplants are currently used in either one of the aforesaid forms. Some of these materials are designed to degrade or to be resorbed inside the body rather than removing the implant after its function is served. Many properties such as mechanical properties, non-toxicity, surface modification, degradation rate, biocompatibility, and corrosion rate and scaffold design are taken into consideration. The current review focuses on state-of-the-art biodegradable bioceramics, polymers, metal alloys and a few implants that employ bioresorbable/biodegradable materials. The essential functions, properties and their critical factors are discussed in detail, in addition to their challenges to be overcome.

Streptococcus mutans forms xylitol-resistant biofilm on excess adhesive flash in novel ex-vivo orthodontic bracket model

INTRODUCTION

During orthodontic bonding procedures, excess adhesive is invariably left on the tooth surface at the interface between the bracket and the enamel junction; it is called excess adhesive flash (EAF). We comparatively evaluated the biofilm formation of Streptococcus mutans on EAF produced by 2 adhesives and examined the therapeutic efficacy of xylitol on S mutans formed on EAF.

METHODS

First, we investigated the biofilm formation of S mutans on 3 orthodontic bracket types: stainless steel preadjusted edgewise, ceramic preadjusted edgewise, and stainless steel self-ligating. Subsequently, tooth-colored Transbond XT (3M Unitek, Monrovia, Calif) and green Grengloo (Ormco, Glendora, Calif) adhesives were used for bonding ceramic brackets to extracted teeth. S mutans biofilms on EAF produced by the adhesives were studied using the crystal violet assay and scanning electron microscopy. Surface roughness and surface energy of the EAF were examined. The therapeutic efficacies of different concentrations of xylitol were tested on S mutans biofilms.

RESULTS

Significantly higher biofilms were formed on the ceramic preadjusted edgewise brackets (P = 0.003). Transbond XT had significantly higher S mutans biofilms compared with Grengloo surfaces (P = 0.007). There was no significant difference in surface roughness between Transbond XT and Grengloo surfaces (P >0.05). Surface energy of Transbond XT had a considerably smaller contact angle than did Grengloo, suggesting that Transbond XT is a more hydrophilic material. Xylitol at low concentrations had no significant effect on the reduction of S mutans biofilms on orthodontic adhesives (P = 0.016).

CONCLUSIONS

Transbond XT orthodontic adhesive resulted in more S mutans biofilm compared with Grengloo adhesive on ceramic brackets. Surface energy seemed to play a more important role than surface roughness for the formation of S mutans biofilm on EAF. Xylitol does not appear to have a therapeutic effect on mature S mutans biofilm.

Influence of resin-modified glass ionomer and topical fluoride on levels of Streptococcus mutans in saliva and biofilm adjacent to metallic brackets

Decalcification of enamel during fixed orthodontic appliance treatment remains a problem. White spot lesions are observed in nearly 50% of patients undergoing orthodontic treatment. The use of fluoride-containing orthodontic materials has shown inconclusive results on their ability to reduce decalcification. The aims of this investigation were to compare the levels of Streptococcus mutans (SM) in saliva and biofilm adjacent to orthodontic brackets retained with a resin-modified glass ionomer cement (RMGIC) (Fuji ORTHO LC) and a light cured composite resin (Transbond XT), and to analyze the influence of topical application of the 1.23% acidulated phosphate fluoride (APF) on SM counts. In a parallel study design, two groups (n=14/15) were used with random allocation and high salivary SM counts before treatment. Biofilm was collected from areas adjacent to the brackets on teeth 13, 22, 33, and 41. Both saliva and biofilm were collected on the 7th, 21st, 35th, and 49th days after appliance placement. Topical fluoride application was carried out on the 35th day. Bonding with RMGIC did not alter SM counts in saliva or biofilm adjacent to the brackets. On the other hand, the biofilm adjacent to brackets retained with composite resin showed a significant increase in SM counts along the trial period. Topical application of 1.23% APF did not reduce salivary or biofilm SM counts regardless of the bonding material. In conclusion, fluoride topical application did not show efficacy in reducing SM. The use of RMGIC as bonding materials allowed a better control of SM cfu counts in dental biofilm hindering the significant increase of these microorganisms along the trial period, which was observed in the biofilm adjacent to the composite material.

Bonding brackets on white spot lesions pretreated by means of two methods

OBJECTIVE

The aim of this study was to evaluate the shear bond strength (SBS) of brackets bonded to demineralized enamel pretreated with low viscosity Icon Infiltrant resin (DMG) and glass ionomer cement (Clinpro XT Varnish, 3M Unitek) with and without aging.

METHODS

A total of 75 bovine enamel specimens were allocated into five groups (n = 15). Group 1 was the control group in which the enamel surface was not demineralized. In the other four groups, the surfaces were submitted to cariogenic challenge and white spot lesions were treated. Groups 2 and 3 were treated with Icon Infiltrant resin; Groups 4 and 5, with Clinpro XT Varnish. After treatment, Groups 3 and 5 were artificially aged. Brackets were bonded with Transbond XT adhesive system and SBS was evaluated by means of a universal testing machine. Statistical analysis was performed by one-way analysis of variance followed by Tukey post-hoc test.

RESULTS

All groups tested presented shear bond strengths similar to or higher than the control group. Specimens of Group 4 had significantly higher shear bond strength values (p < 0.05) than the others.

CONCLUSION

Pretreatment of white spot lesions, with or without aging, did not decrease the SBS of brackets.

In vitro study of the potential protection of sound enamel against demineralization

Background

The objective of this study was to study the potential protection effect of different treatments against sound enamel demineralization around orthodontic brackets.

Methods

This is an in vitro randomized controlled study; artificial enamel demineralization of human premolars was created and compared with reference to control. The three materials used for enamel treatment were resin infiltrate (ICON), fluoridated varnish (Clinpro), and the self-etch primer system (Transbond Plus Self-Etch Primer). Fifty premolars divided equally into five groups were included in the study for quantitative surface micro-hardness assessment using a micro-hardness tester (MHT). Qualitative assessment of the enamel demineralization with a polarized light microscope (PLM) was also used. Enamel was demineralized by subjecting the specimens to cycling between artificial saliva solution and a demineralizing solution for 21 days.

Results

The mean Vickers hardness in kgf/mm² was as follows: intact enamel = 352.5 ± 13.8, demineralized enamel = 301.6 ± 34.0, enamel treated with Clinpro = 333.6 ± 18.0, enamel treated with SEP = 370.7 ± 38.8, and enamel treated with ICON = 380.5 ± 53.8.

Conclusions

ICON, Clinpro, and Transbond Plus Self-Etch Primer (TPSEP) increased enamel resistance to demineralization. Attempting to protect the enamel around the orthodontic brackets could be done by applying a preventive material before bonding, if not compromising the bond strength, the orthodontic brackets.