NO.
1. INTRODUCTION 1
2. HYPOTHESIS 7
3. AIM AND OBJECTIVES 8
4. REVIEW OF LITERATURE 9
5. MATERIALS AND METHODS 26
6. RESULTS 43
7 DISCUSSION 65
8 SUMMARY 79
9. CONCLUSION 83
10. RECOMMENDATIONS 84
11. BIBLIOGRAPHY 85
NO. NO.
1. Distribution based on Retention of the Interventions at 3rd and 6th month
44
2. Distribution based on retention of the interventions at 3rd and 6th month
45
3. Distribution based on the colour match of the interventions at 3rd and 6th month.
48
4. Distribution based on the marginal discolouration of the interventions at 3rd and 6th month.
51
5. Distribution based on the marginal adaptation of the interventions at 3rd and 6th month.
53
6. Distribution based on the caries formation in the interventions at the end of 3rd and 6th month.
56
7. Distribution based on the anatomic form of the interventions at 3rd and 6th month.
58
8. Distribution based on the post-operative sensitivity of the interventions at 3rd and 6th month.
60
9. Distribution based on the surface roughness of the interventions at 3rd and 6th month.
FIGURE NO.
TITLES PAGE
NO.
1. Distribution of the study subjects based on Gender.
43
2. Distribution based on retention between the interventions at 3rd and 6th month.
46
3. Distribution based on colour matching between the interventions at 3rdand 6thmonth.
49
4. Distribution based on marginal discoloration between the Interventions at 3rd and 6th month.
52
5. Distribution based on Marginal adaptation between the interventions at 3 and 6 months.
55
6. Distribution based on Anatomic form between the Interventions at 3rd and 6th month.
59
7. Distribution based on Post-operative sensitivity between the interventions at 3rd and 6th month.
61
8. Distribution based on Surface roughness between the interventions at 3rd and 6th month.
1
INTRODUCTION
Dental caries remains to be a common chronic disease of the childhood.1 Many studies have documented that the occlusal surfaces of posterior permanent teeth are known to be the most susceptible area for the development of dental caries lesions as they have pits and fissures.2Occlusal surfaces, especially those on permanent molars, contain grooves called pits and fissures that can trap debris and microorganisms, thereby increasing the risk of developing dental carious lesions.3Although occlusal surfaces represent only 12.5% of the total surfaces of the permanent dentition, they account for almost 50% of the caries in school children.4
Pits and fissures are considered as the one of the most important morphological feature that leads to development of occlusal caries. Pits and fissures are eight times as vulnerable as smooth surface for dental caries.5 Nagano (1960) described four principal types of fissures, based on the alphabetical description of shape, i.e., Type V – 34%, Type U – 14%, Type I – 19%, Type IK – 26%, and Type Y and others – 7%. The shallow wide V and U shaped fissures tend to be self-cleansing and somewhat caries resistant. The deep narrow I and IK shaped fissures are susceptible to caries.6
2
permanent molars, because recently erupted teeth are less mineralized than those exposed to oral environment for several years. Such teeth have also not undergone the benefits of post eruptive maturation of the enamel and may be thus more prone to acid attack.7 This susceptibility is related to the physical size and individual morphology of pits and fissures, which can be considered as being “shelters” for microorganisms and make the oral hygiene procedures in these areas more difficult, allowing greater plaque retention.8 Another factor responsible for the high incidence of occlusal caries is the lack of salivary access to the fissures as a result of surface tension, effectively preventing remineralization and reducing the effectiveness of available fluoride.9 Occlusal pits and fissures vary in shape, but are generally narrow (0.1mm wide) and tortuous, and are considered to be an ideal site for the retention of bacteria and food remnants. This is because the morphology renders the mechanical means of debridement inaccessible as the average tooth brush bristle (0.2mm) is too large to penetrate in most of the fissures. Other factors such as lack of salivary access to the fissures, the close proximity of fissure base to the dentino-enamel junction and remnants of debris and pellicle in the fissures increase caries susceptibility of fissures by many folds.10
3
have little effect on such surfaces.12 In treating pits and fissures, mechanical fissure eradication was suggested by Bodecker in 1929, recommended reshaping the non-carious pits and fissures into wide non retentive grooves rather than placing restorations. However prophylactic odontotomy and fissure eradication did not become commonly employed because there was a reluctance to perform operative procedures on teeth with no apparent lesions.13
4
material by a resin marked an approach towards a more preventive mode in the caries treatment.16
With the introduction of resin based sealants, properties like, adherence, esthetics and manipulation have been improved.17Resin containing sealant materials can be polymerized by auto-polymerization, photo-polymerization using visible light, or a combination of the two processes.18 Resin-based sealants showed a total retention of 53.12%, partial retention of 18.75%, and 28.12% had been completely lost at the end of the 6 months period.19 Retention depends on morphology of pits and fissures, adequate isolation,conditioning of enamel, application techniques, particular material characteristics like viscosity, surface tension, and adequate adhesion. Mechanical retention of sealants is the direct result of resin penetration into pits and fissures and porous etched enamel surface forming micromechanical tags, where the viscosity of the sealant plays an important role in penetrating and forming micromechanical tags for their retention on the etched surface. The retention rate becomes a major point of concern when a study tests the clinical performance of a fissure sealant material.20
5
fissures is that the clinical procedure is extremely sensitive to moisture, which makes it difficult to etch partially erupted molars.5 Isolation of the tooth with rubber dam is the most important and crucial step of sealant placement because sealing of pit and fissures always carry the risk of contamination which influences an effective seal.22
A recent, significant development with resin based sealants is the development of moisture-tolerant chemistry. In the past, isolation and exclusion of moisture with based sealants was required. A moisture tolerant, resin-based sealant does not require an additional bonding agent.23The first such product to be introduced (Embrace®WetBond; Pulpdent) has physical properties similar to other commercially available sealants.24
6
longevity and clinical effectiveness in retention. It does not include Bis-GMA and therefore contains no Bisphenol-A, which has the potential to bind with the estrogen receptors at sub toxic concentrations leading to cause the impairment in the development, health and reproductive systems which has generated some public concern regarding potential harmful effects.27
7
HYPOTHESIS
RESEARCH QUESTION:
Is there difference in the retention among hydrophilic pit and fissure sealants compared to hydrophobic pit and fissure sealants among school children?
HYPOTHESIS:
RESEARCH HYPOTHESIS:
There is difference in the retention using hydrophilic pit and fissure sealants compared to hydrophobic pit and fissure sealants among school children.
NULL HYPOTHESIS:
8
AIM AND OBJECTIVES
AIM:
To compare the effectiveness of hydrophobic and hydrophilic pit and fissure sealant retention on permanent mandibular first molars among 7-10 year old school children.
OBJECTIVES:
1. To identify early caries lesions using International Caries Detection and Assessment System criteria (ICDAS II, 2005) among the study population.28 2. To compare the effect of sealant retention after using Hydrophobic and Hydrophilic Pit and fissure sealants placed on permanent mandibular first molars among 7-10 year old children at 3rd month and 6th month usingUnited States Public Health Service - Modified Ryge Criteria for Direct Clinical Evaluation of Restorations proposed by Cvar and Ryge, 1980.29
9
REVIEW OF LITERATURE
Simonsen RJ (1991)30assessed the long-term caries prevention and sealant retention 15 years after a single application of auto-cured resin based pit and fissure sealant (Concise White Sealant®) to the four permanent first molars of 200 children. This landmark study o f a pit and fissure sealant at 15 years found 27.6 % complete retention, 35.4 % partial retention and completely missing on 10.9 % of the surfaces on permanent first molars. In the matched pair analysis, carious or restored surfaces made up 31.3 % of the surfaces in the sealed group and 82.8 % in the unsealed group. The odds ratio was 1:7.5. Therefore, it is 7.5 times more likely that a pit and fissure surface on a permanent first molar will become carious or restored after 15 years if it is not sealed, than if it is sealed with a single application of pit and fissure sealant.
10
in 3% of the teeth at 6 months, with the same finding recorded at 12 months. At 18 and 24 months, the sealant was missing in 14% and 21% of the treated teeth, respectively. None of these teeth was affected by caries, suggesting that a part of the sealant was retained in the fissures.
Pulgar et al (2000)32 studied biphenolic components eluted from 7 composites: Charisma® (HeraeusKulzer, Wehrheim, Germany), Pekalux®(Bayern Leverkusen, Germany), Polofil® (Voco, Cuxhaven, Germany), SiluxPlus® (3M, St. Paul, Minn.), Z-100® (3M), Tetric® (Ivoclar, Schaan, Liechtenstein), Brillant® (ColteneWhaledent, Alstatten, Switzerland) and 1 sealant (Delton®, Dentsply, York, Penn.) before and after in vitro polymerization. They found BPA, bis-DMA, bisphenol A diglycidyl ether, bis-GMA, and ethoxylate and propoxylate of bisphenol A in the media in which samples of different commercial products were maintained under controlled pH and temperature conditions. They confirmed the leaching of estrogenic monomers into the environment by bis-GMA based composites and sealants at concentrations similar to those that have produced biologic effects in in vivo experimental models.
11
contralateral teeth, which received only sealant (Fissurit F®, Voco/Cuxhave, assessed at 3, 6, 12 and 24 months using Modified United States Public Health Service (USPHS)-Ryge criteria. The clinically acceptable marginal integrity rates for sealants with a bonding agent after 3, 6, 12, and 24 months were 93%, 93%, 83%, and 79%, respectively. For sealants without a bonding agent, the clinically acceptable marginal integrity rates after 3, 6, 12, and 24 months were 90%, 88%, 81%, and 77%. The rates for no color change in sealants with a bonding agent after 3, 6, 12, and 24 months were 96%, 93%, 81%, and 75%, respectively. For sealants without a bonding agent, the no color change rates after 3, 6, 12, and 24 months were 93%, 93%, 79%, and 72%.The results of this study showed that there were no differences among the sealants with and without bonding agents evaluated in relation to marginal integrity, marginal discoloration, and anatomic form and at the 2-year mark, the placement of a bonding agent under sealants did not significantly affect the clinical success of sealants.
12
sealant was applied to newly erupted molars and was replaced if there had been partial or total loss. Duraphat® fluoride varnish (Colgate-Palmolive Co., New York, N.Y.) was applied to all healthy permanent first molars with partially or fully erupted occlusal surfaces; after 6, 12, 18, 24, 30, 36 and 42 months,varnish was applied to newly erupted molars and was reapplied to all molars that had remained healthy.Results stated that significant difference between the groups, adjusted for multiple molars within each child and cluster (school classes rather than children) random allocation (p < 0.001) for occlusal caries at 9 years: Control: 76.7%; Sealant: 26.6%; Varnish: 55.8%; Effectiveness of treatments: At 4 years: 76.3% (standard error [SE] 7.9%) for sealant vs. control, 43.9% (SE 10.3%) for varnish vs. control, 57.8% (SE 14.7%) for sealant vs. varnish , At 9 years: 65.4% (SE 8.5%) for sealant vs. control, 27.3% (SE 10.2%) for varnish vs. control, 52.4% (SE 12.2%) for sealant vs. varnish.
Yazici AR, Kiremitci A, Celik C, Ozgunaltay G, Dayangac B
13
significant difference between groups;at 12 months, higher retention rate in group II than group I (95.1% vs. 84%, p = 0.025) ;at 24 months, higher retention rate in group II than group I (91.4% vs. 76.5%, p = 0.002) ;total sealant loss: group II, none; group I, 7 sealants (8.6%) at the 24-month recall appointment. The study concluded that air abrasion followed by acid etching resulted in significantly higher sealant retention rates, this method could be a good choice for fissure preparation before sealant placement for long-term success.
14
Subramaniam P, Konde S, Mandanna DK(2008)12 done a clinical study to evaluate the retention of glass ionomer used as a fissure sealant when compared to a self-cure resin-based sealant among 107 children between the ages of 6-9 years at regular intervals over 12 months, using Simonsen's criteria. Two permanent first molars on one side of the mouth were sealed with Delton®, a resinbased sealant, and the contralateral two permanent first molars were sealed with Fuji VII® glass ionomer cement. Comparison of the two sealants at the end of 1 year showed complete retention of 14% of resin sealant as compared to only 0.9% of glass ionomer sealant (2 teeth). This difference was highly significant. Partial sealant retention was seen in 39.3% (81 teeth) that had resin sealant applied, as compared to only 27.7% (57 teeth) that had glass ionomer sealant treatment. This difference was also significant. The results concluded that the loss of the glass ionomer sealants could be inadequate adhesion of the cement to the enamel surface, low wear resistance to occlusal forces.
mesio-15
distally into two halves. These were used to assess the microleakage using stereomicroscope and resin tag length using SEM. Viscosity was assessed using Brooke's field viscometer. The mean value of microleakage for group E is 0.4, group H is 1.0 and group G is 1.6. Group E showed the least microleakage followed by group H and G. The mean resin tag length for Group E is 10.14 ± 4.84;for groupH is 9.65 ± 4.28 and for group G is 5.86 ± 1.85. The mean difference of group E v/s group H is 0.49, group G v/s group H is 3.79 and group E v/s group G is 4.28. The mean resin tag length was highest for group E. The viscosity of the group E was the lowest at 0.96 cP, group H was 1.59 cP and the group G was 1.92 cP. There is a definite negative correlation between viscosity, resin tag length and microleakage. Lower the viscosity, the longer were the resin tags and the microleakage decreased. Embrace wetbond pit and fissure sealant had lowest viscosity, longest resin tag length and lowest microleakage scores.
16
17
Bhat PK, Konde S, Raj SN, Kumar NC(2013)39, carried out an in-vivo study on 80 healthy cooperative children (37 girls, 43 boys) aged between 6 and 9 years who were at high caries risk with all four newly erupted permanent first molars. The present study clinically evaluated and compared the retention and development of caries when sealed with moisture-tolerant resin-based sealant, conventional resin-based sealant with and without a bonding agent, and Glass Ionomer Cement Sealant. Evaluation of sealant retention and development of caries was performed at 6 and 12 months using Modified Simonsen's criteria the 6th month clinical evaluation showed complete retention in 90% of the conventional resin-based sealant with a bonding agent, 81.3% of conventional based sealant without a bonding agent, 91.3% of moisture-tolerant resin-based sealant, and 32.5% of glass ionomer sealant. At 12 months evaluation, complete retention was seen in 81.6% of conventional resin-based sealant with a bonding agent, 72.4% of conventional resin-based sealant without a bonding agent, 80.3% of moisture-tolerant resin-based sealant, and 21.1% of glass ionomer sealant. Development of caries was seen in 2 teeth (2.6%) of groups 1-3 and 5 teeth (6.5%) in group 4 at the 12-month follow-up.
18
immediately and after 1 year. After 1 year, 93 % of Helioseal sealings were complete, whereas 60 % of Embrace sealings showed partial and 13 % complete loss. The surface quality of Embrace was significantly worse than that of Helioseal. After the use of Embrace, the sealant margin was noticeable as a slight(distinct) step in 36 % (15 %). The visual (tactile) examination showed a rough surface in 78 % (33 %) in the case ofEmbrace. The results of this study revealed moisture-tolerant material Embrace was distinctly inferior to Helioseal because Embrace showed weaknesses in retention and surface quality.
19
known that the filler content is the most important factor that affects the amount of shrinkage in resin-based restorative materials.
20
Subramaniam P, GirishBabu KL, and Jayasurya S (2015)43conducted study was to evaluate and compare the retention and caries incidence with use of the two newly introduced moisture tolerant pit and fissure sealants (The glass carbomer sealant and Embrace® Wet Bond sealant) among 200 children aged between 6 and 9 years. Sealants were assessed according to a modified version of the CCC sealants evaluation system at 1,3,6,12,18 and 24 months. . A significantly higher number of mandibular molars sealed with EBW showed more than 50% of the fissures covered with the sealant material at 12 months (p < 0.05).Complete loss of GC sealant from these teeth was significantly higher at 1 and 3months (p < 0.05). On further evaluation at 18 and 24 months, both GC and EBW showed similar pattern of sealant retention. At 24 months, enamel caries was observed in 3 teeth sealed with EBW as compared to only 1 tooth sealed with GC.
21
complete retention, 32.14% showed partial retention, and 3.57% showed complete missing of resin-based unfilled (Clinpro) pit and fissure sealant. This difference in retention rates between filled and unfilled pit and fissure sealants was not statistically significant but Clinpro (unfilled) sealant showed slightly higher retention rates and clinically better performance than Helioseal F (filled).
22
23
Ahovuo-Saloranta A, Forss H, Hiiri A, Nordblad A, Makela M (2016)45 ,done a systematic review and meta-analysis to assess whether dental sealants or fluoride varnishes are more effective for reducing tooth decay on biting surfaces of permanent back teeth in young people. Four trials evaluated this comparison (three of them contributing to the analyses). Compared with fluoride varnish, resin-based sealants prevented more caries in first permanent molars at two-year follow-up (two studies in the meta-analysis with pooled odds ratio (OR) 0.69, 95% confidence interval (CI) 0.50 to 0.94; P value = 0.02; I2 = 0%; 358 children evaluated). The incidence of caries in the control group after nine years was 77% on occlusal surfaces, whereas 26.6% of sealant teeth and 55.8% of fluoride-varnished teeth had developed caries at nine years. The caries-preventive benefit for sealants was maintained at longer follow-up in one trial at high risk of bias: 26.6% of sealant teeth and 55.8% of fluoride-varnished teeth had developed caries when 75 children were evaluated at nine years of follow-up. Evidence suggests that applying resin-based sealants to the biting surfaces of permanent back teeth in children may reduce tooth decay in the permanent teeth of children by 3.7% over a two-year period, and by 29% over a nine-year period, when compared with fluoride varnish applications.
24
EtchantGel + Helioseal F®; Etchant gel + Enamel Loc® ]. The study revealed that the shear bond strengths of the tested materials differed significantly (P = 0.015). Tetric flow 16.8 (MPa) recorded the highest shear bond strength and the difference was statistically significant with Enamel loc (12.8 MPa). On the other hand, Helioseal F has fluoride releasing effect and has shear bond strength of 13.7 MPa. Bond strength is considered to be predictive of the materials' retentive ability based on theconsideration that, the higher the bond strength, the stronger the resistance to curing stress and oral function loading.
25
26
MATERIALS AND METHODS
Study Design: Interventional study.
Study Setting: School-based field setting.
Study Duration: 6 months (May 2018 – November 2018)
Study Population: School children aged 7 - 10 years.
ETHICAL CLEARANCE:
A detailed protocol of the study was prepared and submitted to the Institution Review Board of Ragas Dental College and Hospital, Chennai for scrutiny. This experimental study was started after obtaining ethical clearance (Annexure I).
REGISTRATION IN CLINICAL TRIAL REGISTRY:
The protocol of the study has been registered at the Clinical Trials Registry – India (CTRI) hosted at the ICMR’s National Institute of Medical statistics (http://nims-icmr.in) (Annexure II) [Reference no: REF/2018/05/019842; Trial registration no: CTRI/2018/05/013871]
PERMISSION FROM AUTHORITIES:
27
Correspondent, The Hindu Coronation middle School, Madurantagam (Annexure III) and The Head Master, Government Middle School, Padalam at Kanchipuram district (Annexure IV). Further consent to participate in this study was also obtained from the parents of the study participants in local dialect (Tamil) (Annexure V).
STUDY DESIGN:
This is an interventional split mouth designed study to assess and compare the retention of sealants using two different types of materials, namely hydrophobic and hydrophilic pit and fissure sealants in a school based setting. Sealant placement was done using the two materials according to the manufactures instructions. Retention of these restorations was clinically evaluated using the Modified United States Public Health Service (USPHS) - Ryge criteria29 for direct clinical evaluation of restoration. The study was carried out from May 2018 – November 2018. The restorations were evaluated at the end of the 3rd and 6th month from the date of placement.
ELIGIBILITY CRITERIA: INCLUSION CRITERIA:
28
2. Children scoring 0 or 1 (Sound tooth surface or First visual change) in enamel according to International Caries Detection Assessment System [ICDAS II] criteria for detecting caries in their mandibular permanent first molars.
3. Children whose parents consented for their participation.
EXCLUSION CRITERIA:
1. Children presenting with deep caries, pulpal involvement and restorations. 2. Children with any preventive measures like fluoride application carried out priorly.
3. Children who have enamel defects like amelogenesis imperfecta, enamel hypoplasia and dental fluorosis.
4. Children who had space infections as a complication of the dentition. 5. Children undergoing orthodontic treatment.
6. Children who were under medications for any systemic illness altering the salivary composition and flow.
7. Children who were differentially abled.
29 SAMPLE SIZE ESTIMATION:
The sample size for each group was calculated using the nMaster sample size calculator software, version 2.0 (Annexure VI)
The following inputs were given in the software; the alpha error was set at5% (0.05) with 80% (0.80) as power of the study.
Formula:
(Z1-α + Z1-β)2[πS(1-πS) + πT(1-πT )] n =
(πT-πS -δ) 2
(1.96 + 0.84 )2 [0.76(0.24) + 0.87(0.13)] n =
(0.11-0.4) 2 = 41
Where,
δ : non-inferiority limit of the difference in proportions πT : proportions in test treatment
πS : proportions in standard treatment πT-πS : expected difference in proportions α : significance level
1-β : power
30
size was increased by 10%,a total of 50 subjects were included in the study. Since, the study design was a split-mouth study,50 subjects were chosen to deliver a total 100 interventions, 50 on each side.
RECRUITMENT OF THE STUDY SUBJECTS:
Ten schools in the study site were approached and explained the nature and purpose of the study, out of which two schools gave permission to conduct the study. The schools that participated were Middle School (The Hindu Coronation middle School and Government Middle School) with two sections in each standard and 30students in each class.
31
FLOWCHART ILLUSTRATING THE METHODOLOGY OF THE STUDY:
Included in the study n = 86
Randomization (Split mouth design)
Allotted to group I-Intervention A HYDROPHOBIC PIT & FISSURE
SEALANTS (n=50)
Allotted to group II- Intervention B HYDROPHILIC PIT & FISSURE
SEALANTS (n=50)
Data Analysis and Interpretation of results (n=50)
SEALANT PLACEMENT
ce cement
3rd month follow up: lost to follow up (n= 0) Population assessed for study=360
(7-10 year age school children)
Excluded (n= 274)
Reasons – not suitable for inclusion criteria
Included in the study n = 50
Excluded (n= 36)
Reasons – children whose parents did not wish to consent.
0
Reasons – not suitable for inclusion criteria
32 DATA COLLECTION AT BASELINE: DEMOGRAPHIC DATA:
Questionnaires were provided to all the subjects whose parent’s consented or the study. Data pertaining to age, gender, father’s name/Mother’s name/localguardian’s name and address were recorded prior to the clinical examination.
The study was conducted in two phases,
1. Screening for eligibility (March, 2018)
2. The main study (May, 2018 – November, 2018)
CALIBRATION OF THE EXAMINER:
33 SCREENING FOR ELIGIBILITY:
All the 360 students were screened as per Type III oral examination recommended by American Dental Association (ADA). The subjects were made to sit on an ordinary chair with a head rest facing natural daylight in an upright position, and a torch was used to identify for score 0 or 1(Sound tooth surface or first visual change in enamel) according to ICDAS II criteria (photograph 1,2), proposed by International Caries Detection and Assessment system coordinating committee (Bantinget al,2005).28
Screening was carried out for three consecutive days. The necessary instruments were autoclaved and carried to the school each day. During the screening, for chemical method of disinfection using Korsolex diluted with water was used.Used instruments were washed and placed in the disinfectant solution for 30minutes, then re-washed and drained well. After each day of screening, the entiresets of instruments were autoclaved.
The armamentarium used for screening (Photograph 3) was: 1. Plane mouth mirrors
2. Explorers (No.23 Shepherd’s hook). 3. WHO Probes
4. Tweezers 5. Kidney trays
34 7. Rectangular trays
8. Chip blowers
9. Artificial light source
MAIN STUDY:
The main study was carried out after the screening procedure. Examination and placement of interventions were carried out with the help of the following instruments and supplies (Photographs 4, 5, 6)
1. Portable suction unit (Confident®) 2. Disposable gloves mask and head cap. 3. Mouth mirror
4. Explorer 5. Kidney tray 6. Cheek retractors
7. Local anesthetic gel (Procaine®)
8. Rubber dam kit (GDC Marketing Ltd,Punjab,India) 9. Cotton roll
10. Cotton holder 11. Chip blower
12. 37% Phosphoric acid for acid etching (Actino gel®) 13. Bonding agent(Probond)
35
15. Hydrophilic pit and fissure sealant (Embrace wetbond sealant) 16. Korselax solution
17. Evaluation form
CLINICAL PROCEDURE: STUDY METHOD:
Clinical procedure was carried out on each subject by placement of one of the interventions on the right mandibular molar on the first day and the other intervention was placed on the left side of mandibular teeth on subsequent day. A total of 100 interventions, 2 for each patient, on the left and right side were placed.It took 10 days to complete this procedure with 10 interventions placed on each day and the time taken to place intervention was around 20 minutes per participant. The subjects were asked not to rinse the mouth for 30 minutes and consume any food substances for about one hour after placing the interventions.
INTERVENTION A:
Hydrophobic pit and fissure sealants:
(Helioseal® Assortment, Ivoclarvivadent AG)
PROPERTIES AND COMPOSITION:
36
known as “Bis-GMA”) monomers polymerized by initiator or light of a specific wavelength and intensity. The polymerization of these sealants is also initiated by a catalyst (e.g. camphorquinone), which absorbs light of a specified wavelength of around 470 nm (blue region).
PROCEDURAL STEPS FOR PLACEMENT OF HYDROPHOBIC SEALANT:
1. Pumice prophylaxis was done to the selected teeth prior to start of the study. 2. A local anaesthetic gel (Procaine®-Lidocaine 8%) was applied on the tissues
around the teeth for 10 seconds, which was later rinsed off.
3. The sealant was placed under proper isolation with rubber dam and secured with suction.
4. Occlusal surfaces of the teeth were etched with 37% phosphoric acid for 30 seconds and rinsed with water.
5. The teeth were then dried with a chip blower to achieve a characteristic frosty white, chalky appearance of enamel.
6. Bonding agent was applied on the occlusal surface of the teeth with extra fine brush and light cured for 20 seconds using visible light curing unit.
7. Sealants were then applied and cured according to the manufacturer’s instructions followed by light curing for 40 seconds.
37 INTERVENTION B:
Hydrophilic pit and fissure sealants:
(Embrace wetbond, Pulpdent Corporation,Watertown,USA)
PROPERTIES AND COMPOSITION:
Embrace Wetbond™ is a moisture-activated hydrophilic resin sealant. It contains di-, tri-, and multi-functional acidic monomers in a proprietary formula with hydrophilic in nature for the first time with special features which includeself-priming, self-adhesive, less technique sensitivewith Resin Acid – Integrated Network [R.A.I.N.] an improved hydrophilic resin technology, margin free and hydro-balanced, water activated and pH controlled, Water miscible and protects tooth from micro leakage.The bonding to the tooth structure is chemical as well as micromechanical in nature.5
PROCEDURAL STEPS FOR PLACEMENT OF HYDROPHILIC SEALANT
1. Pumice prophylaxis was done to the selected teeth prior to start of the study. 2. Isolation was done with prefabricated cotton rolls buccally and lingually along
with suction.
38
typical dull, frosted appearance of the etched surface is not desired. Rather, the surface should be lightly dried and very slightly moist with a glossy appearance.
4. To accomplish this, a cotton pellet was used to remove the excess moisture. No bonding agent was applied.
5. The sealant was applied as per manufacturer’s instructions followed by light curing for 40 seconds.
6. Occlusal adjustments were done at the end of the procedure.
POST INTERVENTION INSTRUCTIONS:
The inspection of sealant was done for complete coverage or voids. The children were instructed not to eat or drink anything for 30 minutes. Post intervention instructions and Oral hygiene instructions were given individually to all children. The children were also instructed not to consume carbonated drinks and high sugar containing diet during the study period.
ASSESSMENT OF OUTCOME VARIABLES:
39
until all the participants were examined. No attrition in subjects were noted. Primarily, the retention of the interventions was assessed. Secondary to retention, other factors like colour match, marginal discoloration, secondary caries, anatomic contour, marginal adaptation and surface texture were also assessed. At the end of each follow up, the subjects were asked if they had any discomfort in the sealed teeth during study period and rectified.
CRITERIA FOR ASSESSMENTS:
USPHS Criteria: [Modified United States Public Health Service (USPHS) Ryge Criteria for Direct Clinical Evaluation of Restoration, 1980] was used to assess the interventions.29
Criterion Inspection Method Score
Color Match Visual inspection with mirror at 45cm
A: No shade mismatch in room light in three to four seconds
B: Perceptible mismatch but clinically acceptable
C:Esthetically unacceptable (clinically unacceptable)
Marginal Discoloration
Visual inspection with mirror at 45cm
40
B: Superficial staining (removable, usually localized)
C: Deep staining Marginal
Adaptation
Visual inspection with explorer and mirror, if needed
A: Undetectable crevice along the margin
B: Detectable V-shaped defect in enamel only
C: Detectable V-shaped defect in DEJ
Caries Formation
Visual inspection with explorer, mirror, radiographs
A: No evidence of caries
B: Evidence of caries along the margin of the restoration
Anatomic Form
Visual inspection with explorer and mirror, if needed
A: The restoration is continuous with existing anatomic form
B: Generalized wear but clinically acceptable (50% of margins are detachable, catches explorer going from material to tooth)
41 Postoperative
Sensitivity
Questioning the patients A: No postoperative sensitivity at any time of the restorative process and during the study period
B: Experience of sensitivity at any time of the restorative process and during the study period
Retention Visual inspection with explorer and mirror
A: Retained
B: Partially retained C: Missing
Surface Roughness
Visual inspection with explorer and mirror
A: Restoration is as smooth as the adjacent tooth structure
B: Restoration is rougher than the adjacent tooth structure
42 STATISTICAL ANALYSIS
The following statistical procedures were carried out:- 1. Data compilation and presentation
2. Statistical analysis
I. Data compilation and presentation:
Data obtained were compiled systematically in Microsoft Excel spreadsheet (Annexure VII). The dataset was subdivided and distributed meaningfully and presented as graphs and tables.
II. Statistical analyses:
Statistical analyses were performed using a personal computer in Statistical Package for Social Sciences software (SPSS version 20, USA). Normality distribution of the data was analyzed and specific statistical tests were used to find out the statistical significance of the obtained results. The p value was set for 0.05 and any value equal to or less than was considered to be significant.
1. Normality was assessed using Kolmogorov–Smirnov test as each group had 50 interventions and the data was found to be not normallydistributed.
PHOTOGRAPH-1: SCREENING BY CHIEF INVESTIGATOR
PHOTOGRAPH-3: ARMAMENTARIUM FOR SCREENING
PHOTOGRAPH-5: PIT & FISSURE SEALANTS USED FOR THE STUDYINTERVENTION A - HYDROPHOBIC
PHOTOGRAPH-6: INTERVENTION B - HYDROPHILIC
INTERVENTION A – HYDROPHOBIC PIT &FISSURE SEALANTS PHOTOGRAPH-7: PREOPERATIVE VIEW- RUBBER DAM
ISOLATION
PHOTOGRAPH-9: APPLICATION OF BONDING AGENT
PHOTOGRAPH-11
APPLICATION OFHYDROPHOBIC PIT AND FISSURE SEALANT
PHOTOGRAPH-13: POST OPERATIVE VIEW
PHOTOGRAPH-15: APPLICATION OF THEACID ETCHENT
PHOTOGRAPH-17: POLYMERIZATION WITH CURING DEVICE
PHOTOGRAPH-19:EVALUATION BY THE INVESTIGATOR AT 3RDMONTH
43
RESULTS DEMOGRAPHIC DETAILS:
[image:72.612.199.446.424.616.2]The present study was done to compare the retentive properties of two pit and fissure sealants over a period of 6 months. This split mouth study was done amongst 50 subjects for a period of 6 months who fulfilled the inclusion and exclusion criteria. The subjects were given two interventions, hydrophobic pit and fissure sealant (Intervention A) and hydrophilic pit and fissure sealant (Intervention B), on the occlusal surface of the left and right permanent first molars. All the 50 subjects who were enrolled in both the groups participated for the entire duration of the study period.
Figure 1: Distribution of the study subjects based on Gender.
Figure 1 shows the distribution of the study subjects based on the gender. A total of 19 males and 31 females participated in the study.
62% %%%
44 1. RETENTION
The scoring criteria for retention was such that score A was given if the sealants were completely retained in room light, score B was given if the sealants were partially retained and score C was given for completely missing sealants.
Table 1: Distribution based on Retention of the Interventions at 3rd and 6th month
Scoring criteria
3rd month 6th month Intervention A Intervention B Intervention A Intervention B Completely
Retained 46 47 35 38
Partially
Retained 2 2 10 8
Missing 2 1 5 4
[image:73.612.131.498.273.432.2]45
were completely retained, 10 restorations were partially retained and 5 were lost completely. Assessment of Intervention B showed that 38 restorations were completely retained, 8 restorations were partially retained and 4 restorations were missing.
Table 2: Distribution based on retention of the interventions at 3rd and 6th month
Scoring criteria
3rd month 6th month
Intervention A Intervention B Intervention A Intervention B
Retained 48 49 45 46
Missing 2 1 5 4
Chi square value
0.344 0.122
p value 1.000 1.000
[image:74.612.121.492.271.559.2]46
Intervention A showed that 48 restorations were retained, 2 restorations were missing, while assessment of Intervention B, showed that 49 restorations were retained, 1 restoration was missing. The difference in Retention between the interventions were not statistically significant (pValue = 1.000). At the end of the 6th month, the assessment of the intervention A showed that 45 restorations were retained, 5 were lost completely. Assessment of intervention B showed that 46 restorations were retained and 4 restorations were missing. The difference in the retention between the interventions were not statistically significant (pValue = 1.000) .
Figure 2: Distribution based on retention between the interventions at 3rd and 6th month.
Figure 2 shows the comparison of retained interventions at the end of the third and the sixth months. The assessment of intervention A showed that 48
Intervention A Intervention B Intervention A Intervention B
Misssing 2 1 5 4
Partially Retained 2 2 10 8
Fully Retained 46 47 35 38
0 10 20 30 40 50 60 RETENTION
3rd MONTH 6th MON TH
[image:75.612.119.508.435.617.2]47
restorations at the end of 3rd month and 45 restorations at the end of 6th month were retained. Similarly, intervention B showed 49 restorations at the end of 3rd month and 46 restorations at the end of 6th month were retained respectively. There existed a statistically no significant difference in the retention property among the interventions at the end of 6th month (pValue = 1.000).
2.COLOUR MATCHING
The scoring criteria for color match was such that score A was given if there was no shade mismatch in room light in three to four seconds, score B was given if there was perceptible mismatch but clinically acceptable and score C was given for Esthetically unacceptable (clinically unacceptable) restorations. The results were dichotomized into clinically acceptable (score A and B) and clinically unacceptable (score C) for easy representation.
48
Table 3: Distribution based on the colour match of the interventions at 3rd and 6th month.
Scoring criteria
3rd month 6th month
Intervention A Intervention B Intervention A Intervention B Comp letely Retain ed Part ially retai ned
Total Comp letely Retain ed Part ially retai ned
Total Comp letely Retain ed Part ially retai ned
Total Comp letely Retain ed Part ially retai ned Total Acceptable
Colour match 45 1 46 47 0 47 35 9 44 38 8 46
Unacceptable Colour match
1 1 2 0 2 2 0 1 1 0 0 0
Chi square
value 0.546 1.135
p value
[image:77.612.101.508.187.621.2]49
[image:78.612.142.510.396.580.2](35 restorations were completely retained and 9 restorations were partially retained), 1 restoration (partially retained) had clinically not acceptable colour match. All Forty six restorations of the total intervention B were clinically acceptable (38restorations were completely retained and 8 restorations were partially retained) and none of the restorations were recorded not acceptable. The difference between the interventions was not statistically significant with a pValue of 0.988 at the end of the third month and 0.741 at the end of the sixth month.
Figure 3: Distribution based on colour matching between the interventions at 3rdand 6th month.
Figure 3 shows the comparison of colour matching between the interventions at the end of the 3rd and the 6th month.
Intervention A Intervention B Intervention A Intervention B
UNACCEPTABLE 2 2 1 0
ACCEPTABLE 46 47 44 46
41 42 43 44 45 46 47 48 49 50 COLOUR MATCH
50 3. MARGINAL DISCOLORATION.
The scoring criteria for marginal discolouration was such that score A was given if there was no discolouration anywhere along the margin, score B was given if there was superficial staining (removable, usually localized) and score C was given for deep staining. The scores for marginal discolouration was dichotomized into no discoloration present (score A) and staining present (score B and C) for easy representation.
51
Table 4: Distribution based on the marginal discolouration of the interventions at 3rd and 6th month.
Scoring criteria
3rd month 6th month
Intervention A Intervention B Intervention A Intervention B Comp letely Retain ed Part ially retai ned
Total Comp letely Retain ed Part ially retai ned
Total Comp letely Retain ed Parti ally retai ned
Total Comp letely Retain ed Parti ally retai ned Total No Discolour -ation
42 0 42 45 0 45 33 6 39 36 5 41
Staining 4 2 6 2 2 4 2 4 6 2 3 5 Chi square
value 0.929 0.335
p value 0.639 0.876
52
staining present on them. The difference in marginal discolouration was not statistically significant, with a pValue of 0.639 and 0.876 respectively.
Figure 4: Distribution based on marginal discoloration between the Interventions at 3rd and 6th month.
Figure 4 shows the comparison of marginal discoloration among the interventions at the end of the third month and sixth month.
4.MARGINAL ADAPTAION
The scoring criteria for marginal adaptation was such that score A was given if there was undetectable crevice along the margin, score B was given if there was detectable V- shaped defect in enamel only and score C was given for detectable V- shaped defect in DEJ. The scores for marginal adaptation were dichotomized in to Undetectable crevice along the margin, acceptable marginal
Intervention A Intervention B Intervention A Intervention B
STAINING 6 4 6 5
NO DISCOLORATION 42 45 39 41
0 10 20 30 40 50 60 MARGINAL DISCOLORATION
[image:81.612.144.504.218.398.2]53
[image:82.612.104.492.242.679.2]adaptation (score A) and Detectable V-shaped defect in enamel or dentin, unacceptable marginal discolouration (score B and C).
Table 5: Distribution based on the marginal adaptation of the interventions at 3rd and 6th month.
Scoring criteria
3rd month 6th month
Intervention A Intervention B Intervention A Intervention B Comp letely Retain ed Part ially retai ned Tota l Comp letely Retain ed Part ially retai ned
Total Comp letely Retain ed Part ially retai ned
Total Comp letely Retain ed Part ially retai ned Total Accepta ble
46 0 46 47 0 47 35 0 35 38 0 38
Un Accepta ble
0 2 1(B)
+ 1(C)
2 0 2
2 (B)
2
0 10 6(B) + 4(C)
10 0 8
6(B) + 2(C)
8
Chi square
value 0.344 0.352
54
55
[image:84.612.142.506.172.353.2]Figure 5: Distribution based on Marginal adaptation between the interventions at 3 and 6 months.
Figure 5 shows the difference in the marginal adaptation between the interventions at the end of the 3rd and 6th month.
Intervention A
Intervention B
Intervention A
Intervention B
UNACCEPTABLE 2 2 10 8
ACCEPTABLE 46 47 35 38
0 10 20 30 40 50 60
MARGINAL ADAPTATION
56 5. CARIES FORMATION:
The presence of visual evidence of dark discolouration adjacent to restoration was taken as secondary caries formation. Only clinical evaluation of the caries formation was assessed. There was no caries formation in any intervention after a period of six months. Table 6 shows the distribution of caries formation at the end of six months.
Table 6: Distribution based on the caries formation in the interventions at the end of 3rd and 6th month.
Scoring criteria 3rd month 6th month
Intervention A Intervention B Intervention A Intervention B
No evidence of caries
48 49 45 46
Evidence of caries along the margin of the restoration
[image:85.612.115.513.367.622.2]57 6. ANATOMIC FORM
The scoring criteria for anatomic form was such that score A was given if the restoration is continuous with existing anatomic form, score B was given if there was generalized wear but clinically acceptable( 50% of margins are detachable, catches explorer going from material to tooth) and score C was given for wear beyond DEJ( clinically unacceptable). Scoring for the anatomic form were dichotomized into restoration is continuous with existing anatomic form as acceptable anatomic form (score A) and Generalized wear or wear beyond the DEJ as unacceptable anatomic form (score B) during the analysis for ease of representation.
58
Table 7: Distribution based on the anatomic form of the interventions at 3rd and 6th month.
Scoring criteria
3rd month 6th month Intervention A Intervention B Intervention A Intervention
B Comp letely Retain ed Part ially retai ned
Total Comp letely Retain ed Part ially retai ned
Total Comp letely Retain ed Part ially retai ned
Total Comp letely Retain ed Part ially retai ned Total
Acceptable 46 0 46 47 0 47 35 0 35 38 0 38 Un
acceptable
0 2 1(B)
+ 1(C)
2 0 2
2(B)
2 0 10
6(B) + 4(C)
10 0 8
6(B) + 2(C)
8
Chi square
value 0.344 0.352
p value 0.982 0.889
[image:87.612.106.508.173.583.2]59
[image:88.612.149.498.254.425.2]interventions was not statistically significant at the end of third (pValue = 0.982) and sixth months (pValue = 0.898).
Figure 6: Distribution based on Anatomic form between the Interventions at 3rd and 6th month.
7. POST OPERATIVE SENSITIVITY
The scoring criteria for anatomic form was such that score A was given if there was no post operative sensitivity at the time of restorative process and during the study period and score B was given for experience of sensitivity at any time of the restorative process and during the study period.
Table 8 shows the distribution based on post-operative sensitivity between the interventions at the end of third and sixth month. The assessment of intervention A showed that 47 subjects (46 restorations were completely retained
Intervention A Intervention B Intervention A Intervention B
UNACCEPTABLE 2 2 10 8
ACCEPTABLE 46 47 35 38
0 10 20 30 40 50 60 ANATOMIC FORM
60
Table 8: Distribution based on the post operative sensitivity of the interventions at 3rd and 6th month.
Scoring criteria
3rd month 6th month Intervention A Intervention B Intervention A Intervention B Com plete ly Retai ned Part ially retai ned Tot al Com plete ly Retai ned Par tial ly ret ain ed
Total Com plete ly Retai ned Par tial ly ret ain ed Tot al Com plete ly Retai ned Par tial ly ret ain ed Total
Absent 6 1 47 47 2 49 35 7 42 38 6 44 Present 0 1 1 0 0 0 0 3 3 0 2 2 Chi square
value 1.010 0.211
p value 0.942 1.000
61
[image:90.612.107.471.447.628.2]intervention B showed that a total of 49 subjects (47 restorations were completely retained and 2 restorations were partially retained) as well as 44 subjects (38 restorations were completely retained and 6 restorations were partially retained) did not experience post-operative sensitivity at the end of the third and sixth month whereas 2 subjects reported the experience of post operative sensitivity at the end of the sixth month only. Figure 7 shows the difference in the Post-operative sensitivity between the interventions at the end of the third and sixth months. The difference in experiencing post-operative sensitivity between the interventions was not statistically significant at the end of third (pValue = 0.942) and sixth months (pValue = 1.000).
Figure 7: Distribution based on Post-operative sensitivity between the interventions at 3rd and 6th month.
Intervention A Intervention B Intervention A Intervention B
PRESENT 1 0 3 2
ABSENT 47 49 42 44
38 40 42 44 46 48 50 A xi s Ti tle
POST OPERATIVE SENSITIVITY
62 8. SURFACE ROUGHNESS
The scoring criteria for anatomic form was such that score A was given if the restoration as smooth as adjacent tooth structure, score B was given if the restoration is rougher than adjacent tooth structure and score C was given if the restoration is rougher than adjacent tooth structure and contain pit & fissures. The scoring for surface roughness was dichotomized into restoration is as smooth as the adjacent tooth structure (score A) and restoration is rougher than the adjacent tooth structure (score B) or contains pits and fissures (score C) before analysis for easy representation.
63
Table 9: Distribution based on the surface roughness of the interventions at 3rd and 6th month.
Scoring criteria
3rd month 6th month
Intervention A Intervention B Intervention A Intervention B Com plete ly Retai ned Par tial ly ret ain ed Tot al Com plete ly Retai ned Par tial ly ret ain ed Tot al Com plete ly Retai ned Par tial ly ret ain ed Tot al Com plete ly Retai ned Par tial ly ret ain ed Tot al
Smooth 46 0 46 46 0 46 34 8 42 38 5 43 Rough 0 2 2 1 2 3 1 2 3 0 3 3 Chi
square value
0.677 0.467
p value 0.980 0.834
[image:92.612.103.495.175.583.2]64
month. The difference in surface roughness between the interventions was not statistically significant at the end of third (pValue = 0.980) and sixth months (p-Value = 0.834).
Figure 8: Distribution based on Surface roughness between the interventions at 3rd and 6th month.
Intervention A Intervention B Intervention A Intervention B
ROUGH SURFACE 2 3 3 3
SMOOTH SURFACE 46 46 42 43
38 40 42 44 46 48 50 SURFACE ROUGHNESS
[image:93.612.144.505.244.426.2]65
DISCUSSION
The present study was undertaken to evaluate and compare the retention properties of two pit and fissure sealants, a hydrophobic and a hydrophilic pit and fissure sealants placed on the occlusal surface of the mandibular permanent first molars among 7 to 10 year old subjects over a period of 6 months in Kanchipuram district. The age group of 7- 10 year children were selected for the present study as preventive interventions provides optimal protection of the occlusal surfaces of the first permanent molar teeth, and hence fissure sealants should be placed as soon as possible after eruption of the teeth.7
A split mouth study design was used in this study as it is one of the self-controlled study designs, that is unique in dentistry. This design is characterized by subdividing the mouth of the subjects into homogenous within patient experimental units. In this study design, two treatment modalities can be compared in the same patient at the same duration within a similar oral environment.47 This study design was found to be ideal for the present study, as the aim was to compare the retention of two pit and fissure sealants which had similar caries preventing potential.
66
using modified Ryge (USPHS) criteria at 3rd and 6th month. Many studies have used Simonsen’s criteria for assessment of retention; but retention alone cannot be the only indicator of clinical success of a sealant. Material properties such as solubility are very important in clinical success of restorations and fissure sealants.48 In this study, the retention of the restorations was clinically evaluated using the Modified United States Public Health Service (USPHS) - Ryge criteria for direct clinical evaluation of restoration. The advantage of using this criteria as described by the authors are; (a) it defines key intraoral events to be measured for any clinical trial, (b) describes or ranks the key clinical stages of change, and (c) provides a calibration system for evaluators who might be involved in clinical trials using the system.29 The restoration were assessed for retention primarily and other criteria like colour match, cavosurface marginal discolouration, marginal integrity, anatomic contour, caries formation and surface texture at the end of the 3rd and 6th month.
67
dimethacrylate (BPADMA), leaching out of hydrophobic resin-based sealants tends to bond to estrogen receptors. Hence, a moisture tolerant resin sealant has emerged in the market.
Embrace sealant is self-priming and self-adhesive, hydrophilic in nature and has low technical sensitivity. It is activated with moisture and releases fluoride. It chemically bonds to the tooth structure. It is devoid of Bis-GMA and Bisphenol A.48 Previous studies have proved that the most critical period for sealant failure is at baseline and during the 6th month following application.7
Hence this study compared the retention of two of these pit and fissure sealants
over a period of six months.
RETENTION
68
69
that there was no significant difference in retention among the two study group. This indicates retentive properties of Embrace® to be considerably comparable to the conventional sealant despite the non-usage of rubber dam during the application of the hydrophilic sealant in contrast to the use of rubber dam for the hydrophobic sealant material. Therefore this illustrates that although hydrophilic sealant embrace has lower technical sensitivity48 than Helioseal F, they both have similar retention property. In contrast to the present study, in a study done by Ratnaditya et al, Eighty-one teeth (76.4%) of Group-I sealant(Delton®) was completely retained when compared to ninety-three teeth (87.7%) of group-II (Embrace®) at 6th month. This difference was statistically significant. The reason for this difference in results was because of use of Simonsen’s criteria for clinical assessment of retention by the author in contrast to the present study wherein USHPS criteria was used, which is considered to be more stringent, sensitive and reliable in recording the retention property . The above study also stated that the possible reason for low retention rate of Delton FS® (Intervention A) can be attributed to its hydrophobic property.5
COLOR MATCH
70
compared to the total intervention B (hydrophilic pit and fissure sealant) were 100% (46 restorations) clinically acceptable and none of the restorations were recorded as not acceptable. The difference in the colour match among the restorations was not statistically significant at the end of sixth month. Color plays an important role in obtaining optimum aesthetics.50 Any aesthetic restorative material must simulate the natural tooth in color, translucency and texture.51 The degree of color change can be influenced by a number of factors like incomplete polymerization, water sorption, chemical reactivity, diet, oral hygiene and surface smoothness of the restoration.The structure of the resin and the characteristics of the particles have a direct impact on the surface smoothness and susceptibility to extrinsic staining. Consumption of certain beverages such as coffee and tea may affect the aesthetic and physical properties of resins, thereby undermining the quality of the restoration.52 A study done by Genari et al stated that the interaction with organic acids of beverages induces faster leaching of monomers by catalysis of ester groups from monomers, thereby interact with the polymeric network in free volume spaces between polymer chains, resulting in colored oxidation products.53
MARGINAL DISCOLORATION
71
were usually localized and may be removed using regular oral hygiene procedures. Marginal discoloration of a restoration can be considered as an early indicator of its loss of marginal integrity with the adjacent tooth structure. A restoration discolors at its margins when there is marginal breakdown, which creates a rough and irregular surface. This can act as a niche for the accumulation of plaque and food debris and also promote the penetration of oral fluids and cause microleakage, which can lead to secondary caries formation.37 Marginal fissures occur due to polymerization shrinkage, which in turn is related to cavity geometry, quality of adhesion, curing process and the visco‑elastic properties of the materials. The thermal expansion coefficient of sealants is significantly different from that of enamel, and the mechanics of expansion and contraction of teeth are different from those of sealants. These factors also contribute to microleakage and marginal fissure formation which in turn leads to marginal discoloration.54
72
There was a similar pattern of marginal discolouration on both the sides and interventions in most of the subjects who showed staining. Hence, it may be concluded that this might be due to the dietary habits of the subjects. A study done by Kane et al stated that embrace wet bond shows less polymerization shrinkage than conventional pit and fissure sealants which causes poor marginal seal and marginal discolouration.55
MARGINAL ADAPTATION
73
74 CARIES FORMATION
The present study showed that there was no caries formation in any of the interventions. It is not possible to detect this pathology in a very short duration of 6 months. Success of a pit and fissure sealant mainly depends on its caries-preventive effect. The two sealants were not significantly different in terms of caries formation/occurence in our study, which may be due to fluoride uptake by the adjacent enamel. Even in case of loss of sealant, the rest of the sealant often remains in the grooves and served in protective role.48 Evaluation of sealant retention was performed at regular intervals over 12 months, using Simonsen's criteria by Subramaniam P et al, who had stated that caries formation was very low in these teeth. This can be because even where the material appears clinically to have been totally lost, there may remain small particles of material attached to the enamel of the occlusal fissures.12
ANATOMIC FORM
75
statistically significant. Wear resistance can be attributed to many factors, such as size, hardness, the surface percentage occupied by filler particles, and the interaction between the matrix and the particles ,as well as the degree of polymer resin matrix conversion caused by the applied force and the sliding distance. Filler particles in resin materials play a key role in wear resistance because changes in their composition can promote wear and an increased resistance to degradation.56 Hydrophilic pit and fissure sealants has a filler loading of 36.6%48 by weight making it less viscous, enables better penetrability into pits and fissures.57 Hydrophobic pit and fissure sealants (filler loading of 43% by weight) did not seem to make the sealant more resistant to fracture or marginal fissure formation in comparison to the low viscosity sealants.54 Fernandes et al in his in vitro study stated that high polymerization shrinkage, which in turn is related to cavity geometry, quality of a adhesion and the visco‑elastic properties of the materials resulting in breakdown of the enamel‑sealant micro‑mechanical union.54
POST-OPERATIVE SENSITIVITY
