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Table of Contents   
ORIGINAL RESEARCH  
Year : 2011  |  Volume : 22  |  Issue : 2  |  Page : 205-209
in vitro evaluation of marginal leakage using invasive and noninvasive technique of light cure glass ionomer and flowable polyacid modified composite resin used as pit and fissure sealant


1 Department of Pedodontics and Preventive Dentistry, Rayat Bahra Dental College, Mohali, Chandigarh, India
2 M. M. College of Dental Sciences & Research, Mullana, Ambala, Haryana, India
3 Department of Oral Medicine & Radiology, Rayat Bahra Dental College, Mohali, Chandigarh, India

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Date of Submission06-Apr-2010
Date of Decision11-May-2010
Date of Acceptance11-Oct-2010
Date of Web Publication27-Aug-2011
 

   Abstract 

Aim: This study compared the microleakage of light cure glass ionomer and flowable compomer as pit and fissure sealant, with and without tooth preparation.
Materials and Methods: One hundred premolars that were extracted for orthodontic purpose were used. After adequate storage and surface debridement, the teeth were randomly divided into four groups. In Group I and III, the occlusal surfaces were left intact, while in Group II and Group IV, tooth surfaces were prepared. Teeth in Group I and Group II were sealed with Light cure glass ionomer, whereas flowable compomer was used to seal teeth in Group III and IV. The sealed teeth were then immersed in dye. Subsequently, buccolingual sections were made and each section was examined under stereomicroscope for microleakage followed by scoring. Results: In group I, microleakage score ranged from 2 to 4 with mean of 3.64 (±0.757), while in group II the range was observed to be 1-4 with mean of 2.88 (±1.236). Group III recorded a range of 0-4 with the mean of 2.20 (±1.443) while 0-2 and 0.60 (±0.707) being the range and mean observed, respectively, for group IV.
Conclusion: Flowable compomer placed after tooth preparation showed better penetration and less marginal leakage than the light cure glass ionomer.

Keywords: Invasive technique, marginal leakage, noninvasive technique, pit and fissure sealants

How to cite this article:
Singla A, Garg S, Jindal SK, Suma Sogi H P, Sharma D. in vitro evaluation of marginal leakage using invasive and noninvasive technique of light cure glass ionomer and flowable polyacid modified composite resin used as pit and fissure sealant. Indian J Dent Res 2011;22:205-9

How to cite this URL:
Singla A, Garg S, Jindal SK, Suma Sogi H P, Sharma D. in vitro evaluation of marginal leakage using invasive and noninvasive technique of light cure glass ionomer and flowable polyacid modified composite resin used as pit and fissure sealant. Indian J Dent Res [serial online] 2011 [cited 2019 Oct 14];22:205-9. Available from: http://www.ijdr.in/text.asp?2011/22/2/205/84286
Pits and fissures are generally considered as an imperfections in cuspal odontogenesis. Development of occlusal caries has been considered to be the most important cause of these imperfections. Occlusal caries has become increasingly more difficult to be detected because the typical cavity design in enamel is not present in many cases. [1] Occlusal surfaces alone in optimal fluoridated and nonfluoridated regions represent approximately 55%-65% of all the caries in the 5-17-year old age group. [2] Over the past several decades, a considerable reduction in caries experience has occurred in the pediatric and adolescent population in the developed countries. Smooth surfaces and especially interproximal surfaces have benefited to the greatest extent from the caries preventive effects of various fluoride agents, but caries in pits and fissures remains the portion of the caries experience. Pit and fissure caries may be substantially decreased by obliteration of these developmental defects in occlusal, buccal, and lingual surfaces with sealants. Thus, caries diagnosis is an essential prerequisite when sealant placement is considered, because hidden caries can be inadvertently sealed when bitewing radiographs are not taken.

The clinical efficacy of fissure sealants is directly related to their retention which depends on morphology of pit and fissures, adequate isolation, material characteristics, application techniques. [3] Sealant retention can be improved by cleaning of the occlusal surface prior to sealant placement with pumice prophylaxis, air polishing, air abrasion, and mechanical preparation of fissures known as invasive technique. [4]

Marginal integrity is another important factor for sealant success, which can be appreciated by evaluating microleakage. Microleakage may be defined as the ingress of bacteria, oral fluids into the space between the tooth and restorative material. [5] Lack of sealing allows the occurrence of microleakage, which can prompt caries lesion progression underneath the restoration.

Not much work has been done on the evaluation of the invasive and noninvasive techniques in the manner they affect the microleakage of sealants. Also with the introduction of new fissure sealant materials, it is necessary to re-examine the physical characteristics and technique of fissure sealants. in vitro studies make it possible to assess marginal leakage and predict marginal sealing ability of different materials used as pit and fissure sealants.

Therefore, the purpose of this study was to evaluate the in vitro microleakage of two fluoride releasing materials. The first being resin modified glass ionomer (FUJI II LC) and the second being the flowable polyacid modified composite resin or flowable compomer (Dyract Flow, Dentsply), with and without tooth preparation (invasive and non-invasive technique).


   Materials and Methods Top


This study was conducted in the Department of Pedodontics and Preventive Dentistry, on 100 premolars extracted for orthodontic reasons. These were stored in saline immediately after extraction and used in the study within 30 days. The selected teeth were free from dental caries, restorations, sealants, and fluorosis.

After surface debridement with scaling instruments and cleaning with low-speed micromotor handpiece with polishing brush, the teeth were randomly divided into four groups (I-IV) with 25 teeth in each group. In group I and group III, the occlusal surfaces were left intact (non-invasive technique), while in group II and group IV, the occlusal surfaces were widened (0.5 mm) with a tapering fissure diamond bur (FO-21(MANI Inc)). A maximum of 10 preparations were done with a single bur. The occlusal surfaces of all teeth were flushed with water for 15 s and dried with oil-free compressed air. The pits and fissures of all the specimens of group I and II were conditioned using GC dentine conditioner for 10 s and were then rinsed with water for 10 s before being dried. In group III and IV, the surfaces were etched for 15 s with 35% phosphoric acid gel. They were then rinsed with water spray for 10 s before being dried. Both the materials were applied to teeth with intact occlusal surface, as well as to teeth with prepared occlusal surfaces according to the manufacture's instructions. Care was taken not to incorporate air bubbles. If present, they were removed with an explorer. The materials were light cured for 20 s using visible light cure unit (Dentsply). Varnish was then applied on the sealant and to the adjacent area immediately after curing in group I and II. The samples were then restored in normal saline at room temperature for minimum of 24 h. The restored teeth were then thermocycled at 5 °C, 37 °C, and 55 °C for 250 cycles, with a dwell time of 30 s. All the teeth were triple coated with nail varnish except 1 mm around the sealant margins. The apices of the teeth were sealed with sticky wax. The teeth were then immersed in 5% methylene blue dye solution for 4 h, after which they were washed thoroughly under tap water to remove the superficial dye. The root portions of the samples were cut with diamond disc mounted on a straight hand piece. Crown portions were sectioned longitudinally in a buccolingual direction into two halves through middle of the sealant using a diamond disc mounted on a straight micromotor handpiece with a continuous flow of water. From each crown portion, only one section was selected for scoring. The sectioned samples were examined under a stereobinocular microscope at 20Χ magnification for microleakage at the sealant enamel interface.

The microleakage scoring criteria given by Theodoridou, Tolidas and Papadogiannis [6] was used to assess the extent of dye penetration 0 = No dye penetration [Figure 1]
Figure 1: No dye penetration (Score 0)

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1 = Dye penetration down the lingual or buccal wall [Figure 2]
Figure 2: Dye penetration down the lingual or buccal wall (Score 1)

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2 = Dye penetration down the lingual and buccal wall [Figure 3]
Figure 3: Dye penetration down the lingual and buccal wall (Score 2)

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3 = Dye penetration underneath sealant and down the buccal or lingual wall [Figure 4]
Figure 4: Dye penetration underneath sealant and down the buccal or lingual wall (Score 3)

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4 = Dye penetration all around the sealant [Figure 5]
Figure 5: Dye penetration all around the sealant (Score 4)

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Data collected were subjected to statistical analysis.


   Results Top


Twenty five teeth from each group were evaluated for microleakage using stereomicroscope and scores were recorded using the above mentioned criteria [Figure 6]. It was found that most of the teeth showed microleakage. In some cases, the dye had penetrated through the material rather than the sealant tooth interface, in those cases the amount of dye concentrated near the interface was taken into consideration and not the depth of the dye flowed through the material. The count and the percentage of the microleakage level was evaluated using Pearson chi-square test. In group I, microleakage score ranged from 2 to 4 with mean of 3.64 (±0.757), while in group II the range was observed to be 1-4 with mean of 2.88 (±1.236). Group III recorded a range of 0-4 with the mean of 2.20 (±1.443), while 0-2 and 0.60 (±0.707) being the range and mean observed respectively for group IV. With the GC Fuji II and Dyract Flow on intact occlusal surfaces, the mean values for marginal leakage were 32.46 and 18.54, whereas on prepared occlusal surfaces, the mean values for marginal leakage were 36.32 and 14.68, respectively. Intergroup comparisons were made for all the four groups and also for both the materials and techniques using Mann-Whitney's test. The results were highly significant (P value being 0.001). GC Fuji II showed maximum microleakage, of which invasive technique faired little better than the noninvasive technique. Dyract flow showed the least microleakage, with invasive technique better than the noninvasive technique.
Figure 6: Distribution of teeth among different groups according to microleakage score

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   Discussion Top


An important point to be considered in studies of occlusal caries is the difficulty in evaluation at early stages. Although clinically healthy, pit and fissures may already have carious lesions that are detectable only histologically. When caries begin in both sides of pit and fissures, it becomes harder to detect. Pit-and-fissure sealants have been considered an outstanding adjunct to oral health care preventive strategies in the decrease of occlusal caries onset and/or progression. The properties of an ideal sealing material include biocompatibility, retention, and resistance to abrasion and wear. [7] Sealant bonding to enamel is also important because microleakage at tooth-material interface can lead to treatment failure. An invasive placement technique for preparation of occlusal surface was researched by De Craene and Colls (Preventive resin restoration) which not only provides higher retention rates of sealant, but also gives dentists more self-confidence during its manipulation, especially where clinical evaluation of caries is difficult. [8],[9]

In this study, the in vitro microleakage of two restorative materials, a resin-modified glass ionomer and a flowable compomer were evaluated as pit and fissure sealants. In this study, the light cure glass ionomer cement restorative material is used as it is more retentive than the glass ionomer cement sealant material which may be due to its higher strength. [10] Both the materials were applied with both invasive and noninvasive technique in order to observe the behavior of these materials with and without tooth preparation. The specimens were thermocycled to reproduce the different temperatures to which the teeth are subjected during eating and drinking under clinical conditions. [11],[12]

The two materials and techniques hereby tested differ statistically in terms of microleakage. Several studies have investigated whether caries disease is arrested when dentin lesions are not completely removed. The findings of these works have shown a decrease in the number of cultivable microorganisms in infected dentin after sealant placement. Because of this beneficial effect of sealing dentin caries or incipient enamel caries, the sealing material should fill pits and fissures completely during sealant placement. There are many factors that contribute toward a successful sealant restoration such as properties of enamel, duration of etching, acid used for etching, manipulative variables. However, one of the prime factors governing the efficacy and life expectancy of a sealant is the marginal adaptability. [13] Many studies reported a better efficiency of sealant when using the invasive technique. Different types of burs have been used for mechanical preparation. [6],[13],[14] Geiger et al. found considerably less marginal leakage with a tapered fissure diamond bur than that of round carbide bur. This could be due to smoothening of fissure walls and easier removal of debris by tapered fissure diamond bur. Invasive technique widens and deepens the pits and fissures eliminates organic material and plaque and exposes a more reactive tooth enamel, therefore, enabling a thicker layer of sealant, which would be more wear resistant. [15] Fissure preparation enhances retention by allowing deeper penetration of etchant and sealant and results in superior sealant adaptation. In this study, both glass ionomer and flowable compomer exhibited better sealant penetration, when the occlusal surfaces were prepared.

There are ample studies with regard to microleakage showing dichotomy of results. Various studies have shown that bur preparation followed with acid etching produces sealants with less marginal leakage than conventional methods. [4],[13],[15] This was in accordance with this study, where less microleakage was observed with sealants placed after tooth preparation, as compared to the teeth treated only with prophylaxis and acid etching before sealant placement.

In the case of pit and fissure sealants, the success of this technique can be hindered if the applied material cannot resist microleakage, resulting in the initiation and/or progression of caries under sealed surfaces, as well as increasing the difficulty of diagnosing and treating this lesion. [16] There is a constant search for the material and technique that ensures adhesion to the tooth structure in order to minimize the leakage potential. The present study was designed to evaluate the sealing properties of resin modified glass ionomer cement (Fuji II LC) and flowable compomer (Dyract flow) based on the premise that no available restorative material is perfectly adaptable to the tooth structure. Resin sealants, which possess both low viscosity and excellent wetting properties, have been recommended in dentistry. [17] With low viscosity there is greater potential for the sealant to flow, spread more rapidly over the surface and penetrate. In addition to these properties the material used in the study also possess cariostatic properties as they release fluoride.

Microleakage can be assessed qualitatively or quantitatively with different methods. Dye penetration has been used in this study in accordance with several studies. Methylene blue was used as the dye in the present study for several reasons as it is readily detectable under visible light, soluble in water and it is able to diffuse freely. [18] All the groups showed some amount of microleakage. This finding is in accordance to those reported by Theodoridou Pahini et al. [6] and do Rego et al. [9] who stated that microleakage can be expected in all restorative materials. The most likely explanation for this is that the thermal expansion coefficient of the sealants is significantly different from that of enamel. [19] More microleakage was also seen in glass ionomer. This can be attributed to many reasons but the major reason being there was some amount of disintegration of the sealant due to its solubility.

Since glass ionomer is hydrophilic it has the tendency to absorb the dye into the material and this could give a false positive results. Hence in this study, dye leakage into the material was not taken into consideration, but the presence of the dye in the interface of sealant and the tooth was taken into consideration. This methodology was also followed by Birkenfeld et al. [20] Since the dye is simulating the bacteria and its products, leakage into the glass ionomer material does not have much significance, as it gets neutralized by the fluoride in the material.

Flowable compomer shows least amount of microleakage. This was attributed to its high wetting ability, excellent adaptation to the tooth structure, high surface hardness, exceptional flexural modulus and high elasticity. [21]

Although both the materials were compared only with respect to marginal leakage. In this context, other parameters must be considered when comparing both techniques, such as long term retention, marginal integrity, voids and filling defects etc. Despite its limitations, this study provides some data to support further research into the use of flowable compomers as an alternative to conventional pit and fissure sealant.

 
   References Top

1.Taylor CL, Gwinnett AJ. A study of the penetration of sealants into pits and fissures. J Am Dent Assoc 1973;87:1181-8.  Back to cited text no. 1
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2.Vrbic V. Retention of a fluoride-containing sealant on primary and permanent teeth 3 years after placement. Quintessence Int 1999;30:825-8.  Back to cited text no. 2
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3.Waggoner WF, Seigal M. Pit and fissures sealant application: Updating the technique. J Am Dent Assoc 1996;127:351-61.  Back to cited text no. 3
    
4.Salama FS, Al-Hammad NS. Marginal seal of sealant and compomer materials with and without enameloplasty. Int J Pediatr Dent 2002;20:28-32.  Back to cited text no. 4
    
5.Hatibovic-Kofman S, Wright GZ, Braverman I. Microleakage of sealants after conventional bur and air-abrasion preparations of pits and fissures. Pediatr Dent 1998;20:173-6.  Back to cited text no. 5
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6.Theodoridou-Pahini S, Tolidis K, Papadogiannis Y. Degree of microleakage of some pit and fissure sealants: An in vitro study. Int J Paediatr Dent 1996;6:173-6.  Back to cited text no. 6
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7.Deery C, Fyffe HE, Nugent Z, Nuttall NM, Pitts NB. The effect of placing a clear pit and fissure sealant on the validity reproducibility of occlusal caries diagnosis. Caries Res 1995;29:377-81.  Back to cited text no. 7
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8.De Craene GP, Martens C, Dermaut R. The invasive pit and fissure sealing technique in pediatric dentistry: An SEM study of preventive restoration. J Dent Child 1988;55:34-42.  Back to cited text no. 8
    
9.do Rego MA, de Araújo MA. A 2-year clinical evaluation of fluoride containing pit and fissure sealants placed with an invasive technique. Quintessence Int 1996;27:99-103.  Back to cited text no. 9
    
10.Weerheijm KL, Kreulen CM, Gruythuysen RJ. Comparison of retentive qualities of two glass-ionomer cements used as fissure sealants. J Dent Child 1996;63:265-7.  Back to cited text no. 10
    
11.Crim GA, Swartz ML, Phillips RW. Comparison of four thermocycling techniques. J Prosthet Dent 1985;53:50-3.  Back to cited text no. 11
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12.Palmer DS, Barco MT, Billy EJ. Temperature extremes produced orally by hot and cold liquids. J Prosthet Dent 1992;67:325-7.  Back to cited text no. 12
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14.Garcia-Godoy F, de Araujo FB. Enhancement of fissure sealant penetration and adaptation: The Enameloplasty technique. J Clin Pediatr Dent 1994;19:13-8.  Back to cited text no. 14
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15.Rego MA, Araujo MA. Microleakage evaluation of pit and fissure sealants done with different procedures, materials and laser after invasive technique. J Clin Pediatr Dent 1999;24:63-8.  Back to cited text no. 15
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16.Youssef MN, Youssef FA, Souza-Zarconi WC, Turbino ML, Vieira MM. Effect of enamel preparation mathod on in vitro marginal microleakage of a flowable composite used as pit and fissure sealant. Int J Paediatr Dent 2006;16:342-7.  Back to cited text no. 16
    
17.Xalabarde A, Garcio-Godoy F, Boj JR. Fissure micromorphology and sealant adaptation after occlusal enameloplasty. J Clin Pediatr Dent 1996;20:299-304.  Back to cited text no. 17
    
18.Limkangwal S, Burtscher P, Abbot PV. A comparative study of the apical leakage of four root canal sealers and laterally condensed gutta percha. J Endod 1991;17:495-9.  Back to cited text no. 18
    
19.Bullard RH, Leinfelder KF, Russel CM. Effect of coefficient of thermal expansion on microleakage. J Am Dent Assoc 1988;116:871-4.  Back to cited text no. 19
    
20.Birkenfeld LH, Schulman A. Enhanced retention of glass-ionomer sealant by enamel etching: A microleakage and scanning electron microscopic study. Quintessence Int 1999;30:712-8.  Back to cited text no. 20
    
21.Qin M, Liu H. Clinical evaluation of a flowable resin composite and flowable compomer for preventive resin restorations. Oper Dent 2005;30:580-7.  Back to cited text no. 21
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Correspondence Address:
Anshu Singla
Department of Pedodontics and Preventive Dentistry, Rayat Bahra Dental College, Mohali, Chandigarh
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0970-9290.84286

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