Journal of Indian Society of Pedodontics and Preventive Dentistry
Journal of Indian Society of Pedodontics and Preventive Dentistry
                                                   Official journal of the Indian Society of Pedodontics and Preventive Dentistry                           
Year : 2019  |  Volume : 37  |  Issue : 2  |  Page : 133--139

An In-Vitro evaluation of resin infiltration system and conventional pit and fissure sealant on enamel properties in white spot lesions


Tarang Chadha Arora, Deval Arora, Abhay Mani Tripathi, Gunjan Yadav, Sonali Saha, Kavita Dhinsa 
 Department of Pedodontics and Preventive Dentistry, Sardar Patel Post Graduate Institute of Dental and Medical Sciences, Lucknow, Uttar Pradesh, India

Correspondence Address:
Dr. Deval Arora
Assistant Professor, Autonomous State Medical College, Shahjahanpur - 242 001, Uttar Pradesh
India

Abstract

Background: Clinically appearing early caries are referred to as white spot lesions (WSLs). These lesions compromise esthetics and precede cavitation; therefore, they must be halted by effective materials. Aim: To evaluate and compare the depth of penetration and effect of resin infiltration system (Icon) and other conventional pit and fissure sealants (Clinpro and Embrace) on enamel surface properties of WSLs. Methodology: Freshly extracted premolars were obtained. Enamel surfaces were treated with resin infiltrant and fissure sealant. Depth of penetration and surface roughness of specimens were measured with an optical profilometer. Microhardness was determined by a Vickers' hardness tester. Statistical Analysis: Normality of the data was checked by Shapiro–Wilk test. Inferential statistics were performed using one-way analysis of variance. Post hoc pairwise comparison was done using post hoc Tukey's test. Results: Icon resin infiltrant showed the highest depth of penetration and microhardness followed in descending order by Embrace and Clinpro whereas Clinpro was found to cause maximum surface roughness followed in descending order by Embrace and Icon. Conclusion: The resin infiltration technique for treating WSLs seems adjusted to the philosophy of minimally invasive dentistry in a single appointment, making it beneficial for the patients, especially children.



How to cite this article:
Arora TC, Arora D, Tripathi AM, Yadav G, Saha S, Dhinsa K. An In-Vitro evaluation of resin infiltration system and conventional pit and fissure sealant on enamel properties in white spot lesions.J Indian Soc Pedod Prev Dent 2019;37:133-139


How to cite this URL:
Arora TC, Arora D, Tripathi AM, Yadav G, Saha S, Dhinsa K. An In-Vitro evaluation of resin infiltration system and conventional pit and fissure sealant on enamel properties in white spot lesions. J Indian Soc Pedod Prev Dent [serial online] 2019 [cited 2019 Oct 14 ];37:133-139
Available from: http://www.jisppd.com/text.asp?2019/37/2/133/261345


Full Text



 Introduction



Enamel carious lesions are characterized by mineral loss beneath an apparently intact surface layer. Increased porosity within lesion causes characteristic whitish appearance. Thus, these lesions are often called white spot lesions (WSLs).[1] These classical areas lose their translucency because of extensive subsurface porosity caused by demineralization. If the process is not interrupted, these lesions would result into cavitation.[2]

During demineralization, there is dissolution of calcium hydroxyapatite crystals from enamel and formation of microporosities which promote development of enamel subsurface caries, resulting in chalky white patches on tooth enamel, thereby denoting active lesions.[3] Cycle of de-remineralization is an ongoing phenomenon and takes place in oral cavity with intake of various foods or drinks. However, if oral protective factors, e.g., salivary buffers and fluorides, are unable to keep the balance in favor of remineralization, there occurs a net loss of mineral leading to incipient caries.

Various causes of WSLs include heavy plaque accumulation, inadequate oral home care routines, and high sugar or acid content in diet and during orthodontic therapy due to plaque accumulation on bands and brackets.[4] Multiple preventive agents had been tested over years to evaluate their effectiveness in the prevention and treatment of WSLs. Cements containing fluoride (F), casein phosphopeptide amorphous calcium phosphate (ACP), or ACP.[5] Although remineralization of superficial WSLs is often achieved, this technique shows unsatisfactory results.[6]

Clinpro is a light-cured material with low viscosity with a unique patented color change feature. Fluoride is released from the sealant in a diffusion-limited process by exchange of hydroxide for the fluoride ion.

A newly introduced Embrace Wetbond sealant which is a moisture-tolerant, incorporates di-, tri-, and multifunctional acrylate monomers into an acid-integrating network that is activated by moisture and highly recommended in slightly moist surfaces.[7]

Therefore, prudent use of noninvasive fissure sealants is currently one of the most effective ways to protect caries development on the occlusal surfaces of high-caries-risk children and adolescents.[8] The Icon resin infiltrant acts as a promising alternative therapy for arrest of white spot lesion might be due to infiltration of low-viscosity light-curing resins into subsurface lesion.[9] Hence, the aim of the present study was to compare the depth of penetration, surface roughness, and microhardness of commercially available resin infiltration system (ICON) and fissure sealants (Embrace, Clinpro) using an optical profilometer and Vickers' hardness tester.

 Methodology



One hundred and twenty samples of caries-free extracted premolars were selected for the study. The absence of caries was determined according to clinical parameters using a sharp explorer and 47visual inspection. Tooth specimens were cleaned to remove soft tissue debris and were stored in thymol solution. Teeth were randomly assigned to three experimental groups each for receiving different fissure sealants and one control group of the same size.

The roots of the teeth were removed and crowns were sectioned longitudinally in a mesiodistal direction using a diamond disc with profused water irrigation. Specimens were then embedded in epoxy orthoresin, in such a way that crown portion of the tooth was projected, ensuring that convex smooth tooth surface should be parallel to scanning stage as possible. Artificial enamel lesions were created on tooth surface by immersing them in a demineralizing solution for 4 days at room temperature. The demineralizing solution contains calcium chloride (12 mM), potassium dihydrogen phosphate (10 mM), lactic acid (50 mM), and sodium chloride (100 mM). All were mixed at 37°C for 6 h maintaining a pH of 4.5. Thirty samples were kept in each group (Group A, B, C, and D).

Group A: Smooth surface resin infiltration – Icon (Dental Milestones Guaranteed- DMG America)

Application of etchant: Icon-Etch was applied to the lesion site; after 2 min, etchant was rinsed off with water for at least 30 s and the specimens were dried using an oil-free, water-free air stream. In Icon-Etch, 15% hydrochloric acid was used which removes the superficial layer of enamel so that resin infiltrant can penetrate the lesionApplication of Icon-Dry: Icon-Dry (ethanol) was applied to the lesion site and left for 30 s, followed by drying with an oil-free, water-free air stream which changes the refractive index of the surface of enamelApplication of resin infiltrant: An ample amount of Icon infiltrant was applied to etch surface and allowed to set for 3 min, then light cure for 40 s, using light-curing unit. Icon infiltrant was applied for a second time and rinsed off after 1 min (according to the manufacturer's instructions)Finishing: Excess material was removed by hand using rubber cup and thereafter light curing was performed.

Group B: Conventional pit and fissure sealant – Clinpro (3M, ESPE)

Application of etchant: Etchant containing 37% orthophosphoric acid was applied on the lesion with an applicator tip. After 15 s, the lesion was washed with copious amount of water. Teeth were then gently dried with a three-way syringePlacement of the restorative material: Clinpro was placed immediately on WSLs directly from the syringe by turnable intraoral tip. The material was then light cured for 45 s with the help of a light-curing unit having 450 nm output. The tip of light cure was held as close as possible to restoration during curingFinishing: After removing the excess material, finishing and polishing was done with the help of Shofu's resin finishing and polishing kit.

Group C: Conventional pit and fissure sealant – Embrace (Pulpdent)

Application of etchant: Specimens were dried thoroughly with uncontaminated, oil-free, and moisture-free compressed air. Etchant was applied to the tooth surface for 30 s and rinsed with copious amounts of water. With Embrace WetBond, typical dull, frosted appearance was not required; rather, surfaces were lightly dried and very slightly moist with a glossy appearance. Hence, to accomplish this, a cotton pellet was used to remove the excess moisturePlacement of restorative material: Sealant Embrace was then applied on moist surface followed by light-curing application for 20 sFinishing: After removing the excess material, finishing and polishing was done with the help of Shofu's resin finishing and polishing kit.

Group D: Control group

In this group, no material was applied.

All groups of samples included in the study were then immersed in 1% methylene blue solution for 24 h. The samples were removed and gently brushed to remove excess dye. The specimens were then preserved in artificial saliva for 24 h before the evaluation of depth of penetration, surface roughness, and microhardness. This artificial saliva contains different ratios of methylcellulose, sodium carboxymethylcellulose, and hydroxypropyl methylcellulose. Each of the formulations contains methylparaben 0.2%, potassium chloride 0.062%, magnesium chloride 0.005%, potassium phosphate 0.034%, sodium fluoride 0.01%, dextrose 4.69%, and flavor.

Depth of resin infiltration

The depth of resin infiltrant and sealants on the polished enamel surface was determined by surface profile recordings. Buccal enamel surfaces of the teeth were etched with Group A, B, C, and D. The surface profiles of these specimens were recorded with the help of optical profiling system. Optical profiling uses the wave properties of light to compare the optical path difference between a test surface and a reference surface. The mean values obtained were in micrometer (μm).

Surface roughness test

Surface roughness was analyzed using an optical profiling system. Optical interference profiling is a well-established method of obtaining accurate surface roughness values of the specimens, which were digitally displayed on the screen of roughness tester. Surface roughness was evaluated using the arithmetic mean of the sum of roughness profile values (Ra).

Microhardness test

Microhardness of each specimen was determined using a Digital Micro Vickers Hardness Tester. This tester is equipped with a digital microscope; it shows measuring methods, test force, indentation length, hardness value, and dwell time of the test force as well as number of measurements, all shown on its LCD screen, and looks up the hardness values from the hardness table.

 Results



Graph 1: Intergroup comparison showed that samples of control group were found to be maximum followed by Clinpro, Embrace, and Icon group in decreasing order. The mean surface roughness of control was significantly higher than that of other three groups. The mean surface roughness of Clinpro was significantly higher than that of the Embrace group whereas Icon did not show any significant difference from Embrace and Clinpro groupsGraph 2: Intergroup comparison revealed that Icon showed the maximum depth of penetration followed by Embrace, Clinpro group, and control in decreasing order. The mean depth of penetration of Icon was significantly higher than that of the Embrace group, which was further significantly higher than that of the Clinpro group. The mean depth of penetration of Clinpro group was also significantly higher than that of the control groupGraph 3: Intergroup comparison found that Icon group showed significantly higher microhardness than that of other three groups, i.e., Embrace, Clinpro, and control group. The mean microhardness of control, Embrace, and Clinpro groups did not differ significantly from each other, and these values were found to be statistically significant.[INLINE:1][INLINE:2][INLINE:3]

 Discussion



Initial carious lesions are so-called “white spot” lesion (WSL) which implies that there is a subsurface area with most of the mineral loss beneath a relatively intact enamel surface.[10]

Although fluoride has been used in the prevention of caries, it is more effective on smooth surfaces. Fluoride can only delay the onset of caries in pits and fissures, but will not prevent it. Hence, in the recent years, there is more emphasis on the use of pit and fissure sealants that bonds to enamel and there are various commercially available materials for the same.[11]

Tiny pores within the enamel lesion body act as diffusion pathways for acids and provide path for acid to dissolve minerals which ultimately leads to cavitation. An alternative and novel approach to arrest such carious lesions is to infiltrate these pores with light-curing resins. This approach not only seals the microporosities and blocks the access of acids to any remaining pores, but also significantly increases surface hardness and provides significant mechanical support to tooth tissue.[12]

The procedure was carried out according to the manufacturer's instructions. Teeth were cleaned with pumice and handpiece and then rinsed with water spray. Donnan and Ball (1988) demonstrated that cleaning the debris from the teeth by gently running an explorer through fissures and forcefully rinsing with water resulted in retention rates comparable to those achieved when teeth had been cleaned by a prophy brush and pumice. The levels of sealant retention after surface cleaning with toothbrush prophylaxis or a dry brushing were as high as those associated with handpiece prophylaxis. An evidence-based clinical recommendation for the use of pit and fissure sealants did not specifically address surface cleaning methods, although supporting information acknowledged that the manufacturer's sealant placement instructions should be consulted and that a surface cleaning step typically is included in this instruction.[13]

The results of the present study showed that resin infiltration (Icon) showed minimum surface roughness into initial enamel carious lesions as compared to Embrace and Clinpro groups.

Similar findings of the least surface roughness of Icon were in accordance with the study conducted by Arnold et al. (2016) who stated that resin infiltration resulted in smoothing of the acid-etched enamel surface. This smooth surface should last and prevent further plaque accumulation. Infiltrant of the resin used in this study was triethylene glycol dimethacrylate (TEGDMA). TEGDMA has been shown to have a relatively high solubility that influences the water absorption and the degradation of the polymer.[14]

Graph 1 and [Table 1] showed overall comparison of the mean surface roughness between the study groups, the results of the present study revealed that Group C (Embrace) showed less surface roughness when compared to Group B (Clinpro) but more than that of Group A (Icon).{Table 1}

Similar results were observed by Bhat et al. (2013) and concluded that moisture contamination is a significant risk factor to sealant retention. Therefore, in such conditions, moisture-tolerant resin-based sealant (Embrace) is clinically successful.[7] Clinpro contains bisphenol A-glycidyl methacrylate (Bis-GMA) whereas Embrace incorporates di-, tri-, and multifunctional acrylate monomers; this difference in composition might explain the different surface roughness readings between the materials.[15]

Graph 2 and [Table 2] showed overall comparison of the mean depth of penetration between the study groups revealed that Group A (Icon) showed maximum depth of penetration followed in decreasing order by Group C (Embrace) and Group B (Clinpro).{Table 2}

The results concluded that resin infiltration (Icon) showed maximum depth of penetration into WSLs and similar findings were seen were in studies conducted by Attin et al., Maiti and El-Zankalouny et al. and Gugnani (2017). The use of 15% hydrochloric acid gel (Icon etch) erodes surface layer more effectively than 37% phosphoric acid making it more porous, thereby increasing the depth of penetration.[16],[17],[18],[19]

Comparison of depth of penetration between the study groups showed that Group B (Clinpro) showed minimum depth of penetration followed in increasing order by Group C (Embrace) and Group A (Icon). Similar results of increased penetration depth of Embrace were in accordance with Prabhakar and Reddy et al. (2015) who stated that viscosity of sealant plays an important role in penetrating and forming micromechanical tags for their retention on etched surface. Embrace sealant provided superior adaptation and excellent penetration into fissures compared to Clinpro Bis-GMA-based sealant.[20],[21] This is of interest because acid etching of enamel fissures does not completely penetrate the entire fissure system, and therefore, an intimate adaptation of sealant per se would be an additional benefit to prevent marginal gaps that can induce or enhance bacterial growth in the interfaces and, subsequently, enamel demineralization.[22]

According to Al-Jobair (2013), Clinpro under moist conditions showed least penetration depth.[23] This result was not in accordance with and Khanna et al. (2009) and Mehrabkhani et al. (2015) who stated that resin-based sealants should be less viscous to allow better penetration onto conditioned enamel surfaces.[24],[25]

Graph 3 and [Table 3] showed overall comparison of mean microhardness between the study groups revealed that Group A (Icon) showed maximum microhardness followed in decreasing order by Group C (Embrace) and Group B (Clinpro).{Table 3}

Pancu et al. stated that Icon resin infiltrant showed maximum microhardness compared to conventional sealants.[26] Furthermore, Torres et al. (2012) observed ability of the low-viscosity resin to fill the spaces between the remaining crystals of the porous lesion and the demineralized tissue, improving the mechanical strength of the infiltrated enamel surface.[27]

On overall comparison of mean microhardness between the study groups, the results of the present study revealed that Group B (Clinpro) showed minimum microhardness when compared to Group A (Icon) and Group C (Embrace).

According to Mandava et al., colloidal silica According to Mandava nanoparticles with 8.3-nm particle diameter present as one of the constituents of conventional sealant (Clinpro) have property of maintaining their size and shape remaining in place after drying. These, Silica particles might lodged in enamel voids and seal the porous structures improving the microhardness of enamel, but are not able to penetrate into voids with diameter smaller than particle size, thereby increasing microleakage and decreased microhardness.[28]

Because it is anin vitro study that includes incomplete replication of the complex oral environment and disregard for the effect of saliva and thermocycling, further researches (in vivo studies) are required to overcome the limitation of the study and to check the effectiveness of various tested materials used.

 Conclusion



Resin infiltration system (Icon) showed minimum surface Roughness, maximum microhardness and maximum depth of penetration as compared to conventional pit and fissure sealants tested in present study. Thus, it was found to be a promising, noninvasive approach and might be considered as an additional option to nonoperative and operative treatment approaches. Icon can prevent the progression of lesion body and increase the dental tissue hardness and resistance to acid attacks.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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