COMPARATIVE EVALUATION OF MICROLEAKAGE OF THREE DIFFERENT GLASS IONOMER CEMENTS IN CLASS V CAVITY -
AN IN VITRO STUDY
A Dissertation submitted in partial fulfillment of the requirements for the degree of
MASTER OF DENTAL SURGERY
BRANCH – IV
CONSERVATIVE DENTISTRY AND ENDODONTICS
THE TAMILNADU DR. MGR MEDICAL UNIVERSITY CHENNAI – 600 032
2017 – 2020
DECLARATION BY THE CANDIDATE
I hereby declare that this dissertation titled "COMPARATIVE EVALUATION OF MICROLEAKAGE OF THREE DIFFERENT GLASS IONOMER CEMENTS IN CLASS V CAVITY - AN IN VITRO STUDY" is a bonafide and genuine research work carried out by me under the guidance of Dr.B.RAMAPRABHA, M.D.S., Professor Department Of Conservative Dentistry and Endodontics, TamilNadu Government Dental College and Hospital, Chennai -600003.
KALADEVI. M
CERTIFICATE BY GUIDE
This is to certify that Dr KALADEVI .M, Post Graduate student (2017-2020) in the Department Of Conservative Dentistry and Endodontics, Tamil Nadu Government Dental College and Hospital, Chennai-600003 has done this dissertation titled
"COMPARATIVE EVALUATION OF MICROLEAKAGE OF THREE
DIFFERENT GLASS IONOMER CEMENTS IN CLASS V CAVITY - AN IN VITRO STUDY", under my direct guidance and supervision in partial fulfillment of the regulations laid down by the TamilNadu Dr.M.G.R Medical University Chennai600032, for M.D.S., Conservative Dentistry and Endodontics (Branch IV) Degree Examination .
Dr.B.RAMAPRABHA, M.D.S., Professor&GUIDE
Department of Conservative Dentistry and Endodontics.
TamilNadu Government Dental College and Hospital Chennai- 600003
ENDORSEMENT BY HEAD OF THE DEPARTMENT / HEAD OF THE INSTITUTION
This is to certify that the dissertation titled "COMPARATIVE EVALUATION OF MICROLEAKAGE OF THREE DIFFERENT GLASS IONOMER CEMENTS IN CLASS V CAVITY - AN IN VITRO STUDY" is a bonafide research work done by Dr.KALADEVI .M, Post Graduate student (2017-2020) in the Department Of Conservative Dentistry & Endodontics under the guidance of Dr.B.RAMAPRABHA M.D.S, Professor(Guide), Department Of Conservative Dentistry & Endodontics, TamilNadu Government Dental College and Hospital, Chennai-600003.
Dr.M.KAVITHA M.D.S., Dr.G.VIMALA M.D.S., Professor & H.O.D., Principal
Department of Conservative Dentistry & Endodontics
TamilNadu Government Dental College and Hospital.
Chennai- 600003.
ACKNOWLEDGEMENT
I am taking pride to acknowledge my deep sense of gratitude and respect to my Guide, Dr.B.RAMAPRABHA, M.D.S., Professor, Department of Conservative Dentistry and Endodontics, Tamilnadu Government Dental College and Hospital, Chennai, to whom I am greatly indebted for her constant encouragement, valuable guidance and relentless support throughout the course of this study. Words are few to express my gratitude to her for sparing her precious time, valuable energy and knowledge throughout my post graduate course.
I would like to thank Dr.G. VIMALA, MDS, Principal, Tamilnadu Government Dental College and Hospital, Chennai for permitting me to utilize the available facilities in this institution.
It is my immense pleasure to utilize this opportunity to express my sincere thanks to Dr.M.KAVITHA, MDS, Professor & H.O.D for her suggestions and encouragement in this dissertation.
I sincerely thank Dr. A. NANDHINI, MDS., Dr. P. SHAKUNTHALA, MDS., Associate Professors for their suggestions, encouragement and guidance throughout this study.
My extended thanks to Dr. M. S. SHARMILA M.D.S., Dr. SUDHARSHANA RANJANI M.D.S., Dr. JOTHI LATHA M.D.S., Dr.VENKATESH M.D.S., Dr.DHANALAKSHMI, M.D.S., Dr.BHAKTHAVATCHALAM M.D.S., Dr.
VELAYUDHAM, M.D.S, Dr. PADMAPRIYA, M.D.S, Assistant Professors and my Co- PGs for their timely help in need.
I thank Dr. SRINIVASAN,M.D.S for his statistical guidance and help.
My special thanks to my husband and my children and my relatives for their moral and emotional back up in all my academic pursuits and endeavors and lastly the supernatural for being by my side.
DECLARATION
TITLE OF DISSERTATION Comparative evaluation of microleakage of three different glass ionomer cements in class v cavity - an in vitro study
PLACE OF STUDY TAMIL NADU GOVERNMENT DENTAL COLLEGE AND HOSPITAL
DURATION OF COURSE 3 YEARS
NAME OF THE GUIDE DR B.RAMAPRABHA
HEAD OF THE DEPARTMENT DR M. KAVITHA
I hereby declare that no part of the dissertation will be utilised for gaining financial assistance or any promotion, without obtaining prior permission of the Principal., TamilNadu Government Dental College and Hospital, Chennai -600 003. In addition, I declare that no part of this work will be published either in print or in electronic media without the guide who has been actively involved in dissertation. The author has the right to preserve for publish of the work solely with the prior permission of The Principal, Tamil Nadu Government Dental College and Hospital,
Chennai- 600 003.
H.O.D GUIDE Signature of the Candidate
PLAGIARISM REPORT
CERTIFICATE II
This is to certify that this dissertation work titled “COMPARATIVE EVALUATION OF MICROLEAKAGE OF THREE DIFFERENT GLASS IONOMER CEMENTS IN CLASS V CAVITY - AN IN VITRO STUDY” of the candidate
Dr. KALADEVI. M, with registration number 241717002 for the award of M.D.S in the branch of CONSERVATIVE DENTISTRY AND ENDODONTICS (BRANCH IV). I personally verified the urkund. Com website for the purpose of plagiarism check. I found that the uploaded thesis file contains from introduction to conclusion pages and result shows 13 percentage of plagiarism in the dissertation.
Guide & Supervisor sign with seal
TRIPARTITE AGREEMENT
This agreement herein after the “Agreement” is entered into on this day Jan 2020 between the Tamil Nadu Government Dental College and Hospital represented by its ,Principal having address at Tamil Nadu Government Dental College and Hospital, Chennai - 600 003, (hereafter referred to as, ‘the college’)
And
Mrs. Dr.B.RAMAPRABHA, aged 50 years working as Professor in Department of Conservative Dentistry & Endodontics at the college, having residence at 191/5, Green Fields Apts. R-30A, Thirumangalam High Road, Mugappair,Chennai-3 (herein after referred to as the ‘Principal Investigator’)
And
Mrs. Dr.KALADEVI.M, aged 33 years currently studying as Post Graduate student in Department of Conservative Dentistry & Endodontics, Tamil Nadu Government Dental College and Hospital, Chennai 3 (herein after referred to as the ‘PG student and coinvestigator’).
Whereas the PG student as part of her curriculum undertakes to research on
“COMPARATIVE EVALUATION OF MICROLEAKAGE OF THREE DIFFERENT GLASS IONOMER CEMENTS IN CLASS V CAVITY - AN IN VITRO STUDY”
for which purpose the Principal Investigator shall act as principal investigator and the college shall provide the requisite infrastructure based on availability and also provide facility to the PG student as to the extent possible as a Co-investigator.
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Now this agreement witnesseth as follows
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2.
ABSTRACT
AIM:
The aim of the study is to determine and compare the microleakage and marginal adaptation of three different glass ionomer cements in class v cavity using scanning electron microscopy analysis after thermocycling.
MATERIALS AND METHODS:
Marginal adaptation assessment was done in class v cavity for three different glass ionomer cements under invitro conditions.
(Group 1: Fuji Ix (Control), Group 2: Zirconomer Improved, Group 3: Riva Self Cure, Group 4: Xtracem-S). 40 freshly extracted human mandibular single rooted premolars were used in this study. Class v cavity prepared on the buccal and lingual surfaces of each tooth measuring 3mm wide mesio-distally, 2mm wide occluso-gingivally and 1.5mm deep. Selected samples were randomly divided into four groups of 10 teeth each, and prepared class v cavities restored. The restored teeth were subjected to thermocycling and sectioned longitudinally in a bucco-lingual direction through the center of the restoration. These sections were then examined with a scanning electron microscope under magnification of 1000x. The structure analyzed was the tooth-restoration interface in the occlusal and gingival margins.
RESULTS:
Marginal gap measurement values were tabulated and statistically analysed.
Xtracem-S (GROUP 4) showed least microleakage among the four glass ionomer cements at the significant level, (p<0.01) followed by Riva self cure (GROUP 3), Zirconomer improved (GROUP 2) and Fuji IX (GROUP 1). Highest microleakage was seen with Fuji IX (CONTROL GROUP).
CONCLUSION:
Xtracem-S (GROUP 4) and Riva self cure (GROUP 3) showed comparably least microleakage in this study. Highest comparable microleakage was seen in Fuji IX (GROUP 1) and Zirconomer Improved (GROUP 2).
KEY WORDS: Microleakage, Glass Ionomer Cement, Fuji IX, Zirconomer Improved, Riva Self Cure, Xtracem-S, Thermocycling, Scanning Electron Microscopy.
CONTENTS
S.NO TITLE PAGE NO
1. INTRODUCTION 1
2. AIMS & OBJECTIVES 4
3. REVIEW OF LITERATURE 5
4. MATERIALS & METHODS 26
5. RESULTS 49
6. DISCUSSION 54
7. SUMMARY 62
8. CONCLUSION 64
9. BIBLIOGRAPHY i-x
LIST OF TABLES
TABLE
NO TITLE OF TABLE PAGE
NO
1. Occlusal marginal gap values in microns 48
2. Gingival marginal gap values in microns 49
3. ONE WAY ANOVA TEST for intra-group comparison 51
4. GAMES HOWELL TEST for inter-group comparison 51
1 INTRODUCTION
The basic purpose of the restorative material is to compensate the biological, functional, and esthetic properties of healthy tooth structure. Cervical lesions due to caries, erosion, or abrasion present a special challenge to any restorative dentist because in such cavities, the restorative material is required to adhere to different types of tooth tissues1. Glass ionomer cements are indicated for Class V cavities because their properties include chemical adhesion to tooth structure, anticariogenic effect resulting from fluoride release , thermal compatibility with enamel and dentin, and low setting shrinkage
Glass ionomer cements (GIC) were derived from the basic research on zinc polycarboxylate cements conducted at the Laboratory of the Government Chemist in London during the early 1960.
The first commercially available GIC was DeTrey’s ASPA in 1975 consisting of a newly synthesised high-fluoride glass powder and a copolymer of acrylic and itaconic acid which was proven to be stable indefinitely in a 50 per cent aqueous solution.
Glass-ionomer cements have many properties that are clinically useful and promote longevity.
Importantly, GICs adhere to moist tooth structure and provide a prolonged period of fluoride release, which inhibits recurrent tooth decay. These properties together with acceptable aesthetics and biocompatibility make these materials popular and desirable. However, glass-ionomer dental cements have limitations that prevent broader clinical adaptation such as poor mechanical properties and moisture sensitivity. Many significant changes and modifications to the chemistry of the acidic polymers and basic glasses and to the formulation of the cements have been made to address these limitations.
Metals, fibres, resins, bioactive ion glass and other nonreactive fillers have been evaluated in an attempt to improve the mechanical properties of GICs without compromising the handling or biological characteristics10. In most cases, the bonding between the reinforcing agent and the cement matrix has proven challenging.
2 To overcome the disadvantages of conventional glass ionomer cements regarding strength and wear resistance, Fuji IX43,49 (GC Corporation, Tokyo, Japan) was introduced for use in restoring stress bearing areas. It is a Conventional GIC with a strontium glass which when placed in calcium-containing environment (saliva) will result in calcium ion diffusion into the glass ionomer surface achieving a surface strengthening effect. It is greatly used in atraumatic restorative treatment (ART) technique
ZIRCONOMER IMPROVED50,51 (Shofu inc. Japan) a novel nano sized zirconium dioxide filler reinforced new class of restorative glass ionomer that comprises the strength and durability of amalgam has evolved as a recent posterior restorative material. It is called White Amalgam2. RIVA SELF CURE44,46 (SDI, Australia) a bioactive ion glass filler reinforced newer restorative glass ionomer devoid of resin eliminating risk of volumetric shrinkage and free of bisphenol-A and HEMA.
XTRACEM-S (Medicept Dental, UK), a silver reinforced glass ionomer with improved mechanical proprieties and antibacterial activity to prevent secondary/recurrent caries.
Limited in vitro studies are available for evaluation of properties of the above restorative materials.
Hence these materials are chosen as experimental materials.
In vitro studies have been conducted to evaluate the properities of restorative materials such as microleakage, bond strength, fluoride release, longevity etc. One of the most important requirements for the success of restoration is to prevent the microleakage, which is achieved with the proper adherence of restorative material to the cavity walls. The inadequacy of the restorative materials to attain the complete marginal seal leads to occurrence of microfissures, in which the seepage of ions, fluids, and bacteria occurs, which causes secondary decay, sensitivity, and pulpal infections.
Thermocycling, a protocol in the restorative material study simulating in vivo aging by subjecting materials to cyclic exposures of hot and cold temperatures54.
3 Many different techniques have been used to demonstrate the margins of restorations allowing the active movement of ions and molecules4. These techniques employ the use of bacteria, compressed gas, chemical tracers, scanning microscopy and, maybe most of all, the utilization of dye penetration studies75.
The availability of the scanning electron microscope in dental research has important implications for the investigation of marginal adaptation as it has the advantage of direct visualisation of marginal gaps and its measurement, particularly when compared with results from other leakage studies42.
Hence, the purpose of the current study is to evaluate the microleakage of different glass-ionomer restorations placed in Class V cavities using scanning electron microscopic analysis after thermocycling.
4 AIM AND OBJECTIVES
AIM:
The aim of this study is to compare and evaluate the microleakage and marginal adaptation of three different glass ionomer cements in class v cavity using scanning electron microscopy after thermocycling.
OBJECTIVES:
1. To evaluate marginal adaptation of Fuji IX
2. To evaluate marginal adaptation of Zirconomer improved 3. To evaluate marginal adaptation of Riva self cure
4. To evaluate marginal adaptation of Xtracem-S
5. To compare microleakage between these glass ionomer cements.
5 REVIEW OF LITERATURE
MICROLEAKAGE STUDIES
Warren et al (1988)78 determined an appropriate time interval for treatment of the initially set glass ionomer surface with PAA prior to amalgam condensation. Six groups of 6 samples each were prepared for testing. Five groups consisted of amalgam-bonded-to-glass ionomer samples, while a sixth control group consisted of samples identical in form to those of the other 5 groups, but made of glass ionomer only. On the glass ionomer surface, after the designated PAA treatment time (15, 30, 60, 90, or 120 s) had elapsed, amalgam was hand-condensed. The sample was then stored at 37~ and 90_+1% relative humidity for one week. Earlier pilot work had indicated that no bond formed between amalgam triturate and either untreated or water treated initially set glass ionomer surfaces. At one week from sample preparation all samples were shear-tested in an Instron universal testing machine. A shear bond strength as strong as the shear strength of glass ionomer itself can be effected with PAA between initially set glass ionomer and amalgam at condensation. This bond can be accomplished by thinly coating the initially set glass ionomer surface with 40% PAA for 60 to 120 s prior to amalgam condensation. Evidence for a mechanical component to this adhesive bond has been presented, although the possibility of a chemical
component cannot be excluded at the present time. This study has shown promising in vitro results for this amalgam-PAA glass ionomer bond.
Prati et al (1989)58 evaluated the effects of various dentin chemical pretreatments on the shear bond strength of five glass-ionomer cements (GlCs) and on marginal microleakage of the five GlCs used in association with resin composites in Class V restorations. The dentin treatments were: three acid agents (polyacrylic acid, tannic acid, orthophosphoric acid), three cleansing agents (Tubulicid blue solution, hydrogen peroxide, and sodium hypochlorite), and an aqueous solution as control. After dentin treatment, the test specimens were stored in water at 37°C for 24 hr. Shear bond strength was determined with a universal testing machine at a cross-head speed of 0.5
6 cm/min. Sodium hypochlorite and polyacrylic acid significantly improved the adhesion of GlCs to a different degree in the various materials. Regarding microleakage tests, 320 non-retentive
cavities were prepared at the cementum-enamel junction in freshly extracted human teeth. The teeth were thermocycled, immersed in dye solution, and serial-sectioned longitudinally at three sites. Treatment with sodium hypochlorite was the most effective in reducing marginal leakage.
The present results suggest that dentin treatment is an important step in all resin composite/GlC restorations.
Gordon et al (1991)25 compared 'sandwich' technique restorations with glass ionomer and
composite resin in Class V cavity configurations with walls above and below the cemento-enamel junction. No dye penetration occurred at the occlusal cavosurface margin when the latter was bevelled and light-cured. Scotchbond was applied to the etched enamel before restoration with Durafil composite resin. The least dye penetration at the gingival margin was observed when Ketac bond glass ionomer covered the entire non-bevelled wall. No configuration entirely eliminated dye penetration at the gingival margin.
Isaac Kaplan et al (1992)37 evaluated microleakage of Ketac Fil glass ionomer cement (GIC) and Scotchbond 2 dentinal bonding agent (DBA)/Silux Plus composite resin restorations inserted in cervical cavity preparations of extracted human teeth. After thermocycling, the specimens were invested and sectioned longitudinally and horizontally through the center of the restoration.
Microleakage was evaluated as a ratio of the extent of methylene blue dye penetration at the tooth- restoration interface. Although all restorations exhibited leakage, both the GIC and bonded
composite resin restorations recorded less leakage in retentive than in nonretentive cavity
preparations. Composite resin restorations in nonretentive cavity preparations showed significantly more dye penetration toward the pulpal chamber than the GIC restorations. Ketac Fil GIC
restorations inserted without a matrix strip exhibited less leakage than those with a matrix strip.
The most desirable results were recorded with Scotchbond 2 DBAiSilux Plus composite resin restorations in retentive preparations.
7 Omidi et al (2015)7 evaluated the microleakage of three glass ionomer restorations in class V cavities. Class V cavity preparations were made on the buccal and lingual/ palatal surfaces of 30 human premolars (60 cavities). The specimens were divided into three group (n=10, 20 cavities).
Restored as follows: group1: with Fuji IX (HVGI), group 2: Ionofil molar (HVGI), and group 3:
Fuji II LC (RMGI) / G coat plus. All specimens were finished and polished immediately and were thermocycled (2000 cycles, 5-50°C). In each group; half of the teeth were load cycled (50000 cycles). Finally, the teeth were immersed in 0.15% basic fushcin dye for 24 hours at room temperature and then sectioned and observed under stereomicroscope. It was shown that the mechanical load cycling and filling material did not cause a statistically significant increase in the incisal and gingival microleakage in any of groups. It was concluded that the microleakage of Fuji II LC was similar to that of the highly viscous glass ionomers (Ionofil molar, Fuji IX) and load cycling did not increase the microleakage.
FUJI IX
Hallett et al (1993)28 compared Microleakage of two resin-modified glass ionomer cement (GIC) restorative materials with that of two conventional GIC restorative materials-Fuji II LC, Fuji II, Photac Fil, Ketac Fil in a class v cavity. The occlusal margin was in enamel and the gingival margin was in dentin/cementum. All were restored according to the manufacturers' instructions.
After thermocycling, 30 teeth were placed in 2% basic fuchsin dye for 24 h, sectioned and viewed with a stereomicroscope to assess microleakage. The other 15 teeth were sectioned, replicated and prepared for marginal gap evaluation using a SEM. The resin-modified GIC restorative materials did not consistently seal better than the conventional GIC formulations. In Group I, Fuji IX had a significantly higher resistance to the microleakage test at the occlusal wall compared with FUJI II LC . Although the gingival wall scores for FUJI IX were lower than FUJI II LC , this difference was not significant. PhotacFill sealed significantly more effectively at the occlusal and gingival
8 walls compared with KetacFill. Photacfill showed significantly less microleakage against enamel and dentin/cementum compared to the conventional GIC
Hosoyo et al (1998)35 evaluated the bonding mechanism to enamel and dentin of two chemically- cured restorative glass ionomer cements. Ketac-Molar Aplicap (after conditioned with Ketac- Conditioner) and Fuji IX GP (after conditioned with Cavity Conditioner) was applied on the enamel and dentin. Ketac-Molar Aplicap was coated with Ketac-Glaze and Fuji IX GP with GC Fuji Varnish. After 24-hr immersion in water, bonding interfaces were coated with gold-palladium and observed under the SEM. For both Ketac-Molar Aplicap and Fuji IX GP, an intimate
adaptation between the material and the enamel was observed. Both materials bonded to dentin without gap formation.
Glasspoole et al (2002)19 evaluated the effect of various surface treatments on the bond strength of several glass ionomers to enamel, and to examine the resulting bond interface. (1) no pretreatment, (2) Vitremer primer, (3) 10% polyacrylic acid or (4) 35% phosphoric acid. A conventional glass ionomer fuji ll and two resin-modified glass ionomers (RMGI's) fuji ll LC and vitremer were bonded to the pretreated enamel surfaces, stored in water for 24h and shear bond strengths
measured. Transverse sections of similarly prepared samples were etched with phosphoric acid for 60s to partially remove enamel and expose the enamel/glass-ionomer interface. The interface morphology was examined by SEM. Polyacrylic acid and phosphoric acid conditioning resulted in significantly increased bond strength to enamel for all three glass ionomer materials, compared to no pretreatment (p<0.01). Light-cured bond strengths were in most cases, significantly greater than when self-cured (p<0.01). Examination of the bonded interfaces revealed the presence of polymer tags in the enamel conditioned with polyacrylic acid and phosphoric acid.
Katleen et al (2008)39 investigated microleakage in class V cavities following restoration with conventional glass-ionomer cements (CGICs) or resin-modified glass-ionomer cements
(RMGICs), following Er:YAG laser or conventional preparation.Three hundred and twenty class V cavities were assigned to four groups: those in groups A and B were prepared using an Er:YAG
9 laser, and those in groups C and D were conventionally prepared. In groups B and D the surface was additionally conditioned with cavity conditioner. Each group was subdivided according to the GIC used: groups 1 (Fuji II), 2 (Fuji IX), 3 (Fuji II LC) and 4 (Fuji VIII). After thermocycling, the specimens were immersed in a 2% methylene blue solution, sectioned oro-facially, and analyzed for leakage. The effect of the conditioner was analyzed using a scanning electron microscope (SEM).Significant differences between occlusal and gingival margins were found in all groups except B4, D3, and D4. Comparison of preparation methods (groups A–D) revealed significant differences at the occlusal margin in groups 1 and 3, but in all groups at the gingival margin. Laser preparation without conditioning allowed more leakage. Comparison of filling materials (groups 1–4) revealed significant differences in groups B and C at the occlusal margin, and in all groups at the gingival margin. In these groups, laser-prepared cavities (with or without conditioning)
restored with Fuji II LC and Fuji VIII showed the least leakage at both margins. RMGICs allowed less microleakage than CGICs. Complete marginal sealing was not achieved and conditioning is recommended.
Shaila et al (2011)64 compared and evaluated the microleakage of two modified glass ionomer cements on deciduous molars- GC Fuji II LC (Improved) and GC Fuji IX GP in a class v cavity using dye penetration method. GC Fuji II LC (Improved) showed more microleakage in dentin as compared to GC Fuji IX GP. GC Fuji IX GP demonstrated more microleakage in enamel as compared to GC Fuji II LC (Improved).
Yassini et al (2011)48 evaluated marginal integrity in three types of class V tooth-colored restorations and the effect of load cycling on their microleakage using scanning electron
microscopy. In this in vitro study, class V cavity preparations were made on the buccal and lingual surfaces of 30 bovine incisors (60 cavities). The specimens were divided into three groups (n=10 each or 20 cavities) and restored as follows: group 1: with Filtek Z350 (nanocomposite), group 2:
Fuji IX (CGIC), and group 3: Fuji II LC (RMGI ). All specimens were finished and polished immediately and were thermocycled (×2000, 5-50 °C). In each group, half of the teeth were load
10 cycled .Epoxy resin replicas of 12 specimens were evaluated under FE-SEM and interfacial gaps were measured. Finally the teeth were immersed in 0.5% basic fuchsine dye for 24 hours at room temperature, sectioned and observed under stereomicroscope. It was shown that the mechanical load cycling caused a statistically significant increase in cervical microleakage of Fuji IX and Fuji II LC and in incisal microleakage of Fuji II LC. Microleakage in Z350 with load-cycling and Fuji IX with and without load-cycling was significantly higher in cervical compared with incisal area.
Both incisal and cervical microleakage were significantly different among these materials under load-cycling. ( Fuji II LC < Fuji IX < Z350 ).It was concluded that the marginal sealing ability of Fuji IX under load-cycling was better than that of Fuji II LC. Z350 showed better marginal integrity while being load-cycled than both Fuji II LC and Fuji IX .
Teena et al (2012)74 evaluated the microleakage of recently available glass ionomer based
restorative materials (GC Fuji IX GP, GC Fuji VII, and Dyract) and compared their microleakage with the previously existing glass ionomer restorative materials (GC Fuji II LC) in primary and permanent teeth in a class I Cavity. It was found that there was no statistically significant difference when the means of microleakage of primary teeth were compared with those of permanent teeth. GC Fuji IX GP showed maximum microleakage and GC Fuji VII showed least microleakage.
Diwanji et al (2014)27 compared the microleakage of glass ionomers (conventional and resin modified) with that of recently introduced nanoionomers- Fuji IX, Fuji II LC, and newly
introduced Ketac N 100 (KN 100). Samples were thermocycled and submerged in Acridine dye for 24 h. Samples were sectioned to view under fluorescent microscope and marginal leakage was evaluated. Fuji IX showed the maximum leakage, followed by LC II and the least was observed in KN 100.
Jiang et al (2014)80 examined the effects of Er:YAG laser in improving the binding of the glass ionomer cement (GIC) to enamel surfaces. Briefly, 77 human premolar and molar teeth free of visible caries were used from the study and treated with different methods, including regular
11 abrasion with diamond saw (Bur), 10 polyacrylic acid, 37% phosphoric acid, and/or Er:YAG laser.
The shear bond strength (SBS) between GIC and enamel surfaces were measured; the patterns of the junction between GIC and enamel were observed by scanning electron microscopy (SEM);
failure patterns were analyzed with stereomicroscope to determine the adhesive and cohesive patterns of the fracture. The results showed that the treatment of Er:YAG laser resulted in a higher SBS values than that of bur. The use of 10% polyacrylic acid could improve the GIC bonding to the bur-prepared enamel, but not for laser-prepared enamel surface. However, the treatment with 37% phosphoric acid increased the SBS dramatically both in bur-prepared and laser-prepared groups. The failure mode analysis and SEM observation demonstrated a cohesive failure within the cement. In conclusion, the treatment of Er:YAG laser was beneficial for the adhesion of GIC to enamel.
Hoshika et al (2015)34 determined the bond stability and the change in interfacial ultrastructure of a conventional glass ionomer cement (fuji IX GP EXTRA) bonded to dentin, with and without
pretreatment using a polyalkenoic acid conditioner under transmission electron microscopy (TEM). TEM observation showed a demineralized layer and an amorphous gel phase in the polyalkenoic acid conditioned group. It was concluded that Aging did not reduce the bond strength of the conventional glass-ionomer cement to dentin when the surface was pretreated with a polyalkenoic acid conditioner.
Doozandeh et al (2015)45 evaluated the effect of CPP-ACP paste pretreatment on the
microleakage of three types of GIC. Class V cavities were prepared on the buccal and lingual surfaces of molars with occlusal margins in enamel and gingival margins in root. The cavities were divided into 6 groups. Cavities in group 1 and 2 were restored with Fuji II, group 3 and 4 with Fuji II LC, and group 5 and 6 with Ketac N100 with respect to the manufacturers’ instructions. In groups 2, 4 and 6, CPP-ACP containing paste (MI paste) was placed into the cavities for 3 minutes before being filled with GIC. The teeth were thermocycled, stained with dye, sectioned, and scored for microleakage under stereomicroscope.CPP-ACP paste pretreatment did not affect the
12 microleakage of Fuji II and Ketac N100 in enamel or dentin, but decreased the microleakage in dentine margins of Fuji II LC when cavity conditioner was applied before surface treatment.
Suvidh et al (2016)73 measured the amount of fluoride released from fluoride containing materials. Zirconia reinforced glass ionomer cement (Zirconomer, SHOFU INC), high density glass ionomer cement (Ketac Molar, 3MESPE) and packable posterior glass ionomer restorative material (GC Fuji IX GP) after immersion in artificial saliva using Ion Specific Electrode (ELIT 9801). Higher rate of fluoride release was observed in packable posterior glass ionomer material compared to zirconia reinforced glass ionomer material and high density glass ionomer material.
Sairaj et al (2017)61 compared and evaluated the influence of ultrasonics, halogen light and combined result of each on microleakage of enamel adjacent to fuji IX glass ionomer restorations after thermocycling using dye penetration and stereomicroscopic evaluation. Halogen light
decreased the microleakage of enamel adjacent to fuji IX glass ionomer restorations.
Balgi et al (2017)8 compared the micro-leakage of two newer glass ionomer cements (SDI Riva Self Cure GIC and GC Fuji IX GP EXTRA) in class v cavity in primary molars immersed in sugarcane juice, chocolate milk and mango drink. Micro-leakage was determined by dye
penetration under 40 x stereomicroscope. Both the materials showed microleakage when immersed in the three beverages. When specimen under each group were compared, the microleakage score increased with an increase in immersion frequency. This was not statistically significant.
Sahu et al (2018)16 compared the microleakage of GC Fuji II, GC Fuji IX GP, and GC Fuji II LC in a class v cavity. Samples subjected to thermocycling and later on immersed in methylene blue dye and microleakage assessment was done using stereomicroscope. GC Fuji II exhibited
maximum microleakage, followed by GC Fuji IX GP and was minimum in GC Fuji II LC.
Manal et al (2019)43 evaluated GC Fuji II LC (Light-Cured, Resin-Reinforced Glass Ionomer Restorative) and GC Fuji IX GP EXTRA (Packable Glass Ionomer) when used to restore occlusal caries in lower second primary molars. Clinical assessment was performed after 3, 6, 9 and 12 months according to United States Public Health Services (USPHS) evaluation criteria and rating
13 system. Fuji II and Fuji IX showed comparable marginal adaptation. Fuji II restorations showed better results regarding anatomic form, secondary caries and marginal discoloration when compared to Fuji IX.
ZIRCONOMER AND ZIRCONOMER IMPROVED
Prabhakar et al (2015)59 assessed the clinical performance of zirconia (ZrO2) infused glass ionomer cement (GIC) compared to conventional GIC. Cavities were prepared on bilateral teeth and restored with Conventional GIC on one side and ZrO2infused glass ionomer on the other. The two sides were compared with regards to their clinical performance and color stability.
ZrO2infused GIC showed better color stability but conventional GIC was much better as far as color match, surface texture, and marginal adaptation were concerned.
Rashmeet et al (2016)60 evaluated and compared the microleakage and compressive strength of Ketac Molar, Giomer, Zirconomer, and Ceram-x in a class v cavity. The samples were
thermocycled and subjected to dye penetration test evaluated under stereomicroscope at × 40 magnification. The sealing ability was maximum in Ketac Molar whereas the compressive strength was maximum for Giomer followed by Ceram-x, Zirconomer, and Ketac Molar.
Saxena et al (2016)63 compared constituents of glass powder, fluoride release, and antimicrobial properties of zirconomer and Fuji IX. This in vitro study comparing Zirconomer and Fuji IX was executed in three parts: (1) energy dispersive X-ray microanalysis of glass powders (2) analysis of fluoride release at 1st, 3rd, 7th, 15th, and 30th day, and (3) antimicrobial activity
against Streptococcus mutans, Lactobacillus casei, and Candida albicans at 48 hours. Energy dispersive X-ray microanalysis revealed that, in both Zirconomer and Fuji IX glass powders, mean atomic percentage of oxygen was more than 50%. According to the weight percentage, zirconium in Zirconomer and silica in Fuji IX were the second main elements. At all the time intervals, statistically significant higher amount of fluoride release was observed with Zirconomer than Fuji IX. Zirconomer had higher antibacterial activity against Streptococcus mutans and Lactobacillus
14 casei, which may be attributed to its composition and higher fluoride release. However, it failed to show antifungal effect against Candida albicans.
Bhatia et al (2017)33 compared the sorption, solubility, and compressive strength of three different glass ionomer cements in artificial saliva - type IX glass ionomer cement, silver- reinforced glass ionomer cement, and zirconia-reinforced glass ionomer cement. Zirconomer showed the highest compressive strength followed by Miracle Mix and least compressive strength is seen in gc type IX-Extra with statistically significant differences between the groups. The sorption and solubility values in artificial saliva were highest for GC type IX – Extra followed by Zirconomer and Miracle Mix.
Sharafeddin et al (2017)21 evaluated the microhardness of glass-ionomer modified withdifferent materials. Glass ionomer (Shofu,Japan), zirconia reinforced glass ionomer (Zirconomer, Shofu, Japan), silver reinforced glass ionomer (HI DENSE XP, Shofu, Japan) and mixture of these three types of glass ionomer with 20 wt% of microhydroxyapatite. Zirconia reinforced glass ionomer with microhydroxyapatite exhibited significantly higher microhardness. After incorporation of microhydroxyapatite in both conventional and silver reinforced glass ionomer groups,
microhardness decreased significantly.
Shameera et al (2017)65 compared and evaluated microleakage, surface roughness and hardness of three glass ionomer cements – Zirconomer, Fuji IX Extra GC and Ketac Molar in a class v cavity. Teeth were themocycled for 500 cycles and were placed in 0.5% methylene blue for 24 hrs. Volumetric microleakage evaluation was done using spectrophotometer. Microleakage value of Zirconomer was greater.
Shetty et al (2017)12 evaluated and compared the compressive strength of restorative materials Ketac Molar, Zirconomer, and Zirconomer Improved. All the tested restorative materials exhibited sufficient compressive strengths with Zirconomer exhibiting significantly higher compressive strength.
15 Salman et al (2019)50 evaluated the adaptability of new novel restorative material Nano-ionomer with resin-modified glass ionomer, Zirconomer, Giomer to tooth surface by measuring the degree of microleakage at gingival and occlusal restorative margins of Class V cavities and compared the same among the groups using stereomicroscopic study. Specimens were thermocycled, immersed in Methylene blue dye, sectioned longitudinally and analyzed for leakage at the occlusal and cervical interfaces. It was concluded that all the restorative materials tested shows microleakage to an extent. Nano-ionomer was better than the other three types of glass ionomers in reducing the microleakage.
RIVA SELF CURE
Bonifacio et al (2009)10 evaluated mechanical properties of glass ionomer cements (GICs) used
for atraumatic restorative treatment. Wear resistance, Knoop hardness (Kh), flexural (Fs) and compressive strength (Cs) were evaluated. The GICs used were Riva Self Cure (RVA), Fuji IX (FIX), Hi Dense (HD), Vitro Molar (VM), Maxxion R (MXR) and Ketac Molar Easymix (KME).
Data suggested that KME and FIX presented the best in vitro performance. HD showed good results except for early‐term wear.
Ghasemi et al (2012)23 assessed the effect of bonding application time on the microleakage of
Class V sandwich restorations. Three groups were restored with Fuji II GIC and treated with a total-etch bonding system (Stea ⁄ SDI) immediately after insertion, at 7 minutes and 15 minutes after mixing the glass ionomer cements (GICs). Another three groups were restored with Riva Self Cure GIC and treated with the total-etch system identically. The other six groups were subjected to self-etching bonding (Frog ⁄ SDI) after GIC placement in an identical procedure. The remaining groups were made using light cure GICs (Fuji II or Riva Light Cure) in conjunction with the total- etch or self-etching systems. Cavities were then restored with composite (Valux plus, 3M⁄ESPE).
Samples were subsequently immersed in 2% methylene blue solution for 48 hours and observed under a stereomicroscope.The self-etching bonding system exhibited more microleakage in
16 occlusal margins regardless of time. Over time, microleakage significantly decreased in gingival margins in all self-cure groups except for Riva Self Cure treated with the total-etch system.
Nurulnazra et al (2017)53 compared four commercially available conventional GIC -Fuji VII, Riva Protect, Riva Self Cure and Fuji IX GP Extra respectively based on the amount of fluoride release, marginal integrity using dye penetration under stereomicroscopic evaluation and ability to increase microhardness of underlying artificial dentinal caries via remineralization. . In the present study, low-viscosity GICs exhibited more microleakage compared to the high-viscosity variants.
texture of Fuji VII and Riva Protect were found on stereomicroscope photographs to be more granulated with many cracks and air voids, which might result in the leakage in the present study.
XTRACEM-S
No previous studies found in the literature search for Xtracem-s. But studies regarding silver reinforced GICs found in the literature.
Yap et al (1996) evaluated microleakage associated with a silver reinforced restorative glass ionomer cement (Hi Dense) used alone and also as a laminate restoration with a composite resin and dentine adhesive in extracted premolar and molar teeth. The influence of artificial saliva, thermal and load cycling was also determined. The composite (Z 100) and dentine adhesive (scotchbond universal) alone were used for comparative purposes. The results showed that the composite resin/dentine adhesive restorations showed substantial microleakage at both the cervical and occlusal margins of the Class II restorations, whereas the glass ionomer alone showed little or no leakage after storage in water for seven days at 37°C. These results were confirmed when the restorations were thermo-cycled and load stressed. The addition of glass ionomer as a base to the composite forming the laminate restoration reduced the leakage substantially and in certain conditions the leakage was less than that observed with glass ionomer restoratives alone.
Yap et al (1997)79 evaluated the influence of conditioners on the enamel and dentine margin sealing ability of three different silver reinforced glass-ionomer cements. Two Class V
17 preparations were made on the buccal and lingual surfaces of 36 freshly extracted molar teeth.
Preparations were solely in enamel or dentine/ cementum. The teeth were randomly divided into three groups of 12 and restored with either Ketac Silver (KS), Hi-Dense (HD) or Miracle-
Mix®(MM) with and without (-C) their respective conditioners. All materials were capsulated and were manipulated according to the manufacturers' instructions. The restorations were finished as recommended by the manufacturers and then stored in saline at 37°C for 1 week, polished, thermally stressed, subjected to dye penetration, sectioned and scored. Rankings in the order of decreasing leakage were as follows: enamel margin KS > KS-C > HD-C > HD > MM > MM-C;
dentine margin KS > HD-C > KS-C > HD> MMC > MM. At the enamel margins, only HD showed a significant increase in leakage when conditioner was not used. At the dentine margin, however, KS had significantly more leakage than KS-C and HD-C had significantly more leakage than HD. There was no significant difference in leakage for MM both with and without
conditioner. The influence of conditioners on marginal leakage appears to be botb product and tissue specific.
Yap et al (2007) evaluated microleakage associated with a silver‐reinforced restorative glass–
ionomer cement (Hi‐Dense) used with a composite resin (Z100) in a modified Class II
bonded‐base technique restoration . The influence of long‐term artificial saliva storage, thermal and load cycling was also determined. Class II composite (Z100) restorations used with a new dental adhesive system (Scotchbond Multi‐Purpose Dental Adhesive) were used as controls.
Results showed that the bonded‐base technique can reduce the leakage observed with the direct composite technique. Thermocycling decreased the leakage at the composite–enamel interface but had no effect on the leakage at the composite–dentine interface or on the leakage patterns of bonded‐base restorations. Load cycling had no significant influence on leakage patterns of either type of restorative mode. Storage in artificial saliva resulted in decreased leakage at the
composite‐enamel interface but had a minor adverse effect at the glass–ionomer–dentine interface.
18 Sharafeddin et al (2017)21 evaluated the microhardness of glass-ionomer modified withdifferent materials. Glass ionomer (Shofu,Japan), zirconia reinforced glass ionomer (Zirconomer, Shofu, Japan), silver reinforced glass ionomer (HI DENSE XP, Shofu, Japan) and mixture of these three types of glass ionomer with 20 wt% of microhydroxyapatite. Zirconia reinforced glass ionomer with microhydroxyapatite exhibited significantly higher microhardness. After incorporation of microhydroxyapatite in both conventional and silver reinforced glass ionomer groups,
microhardness decreased significantly.
THERMOCYCLING PROCEDURE
Many studies of marginal leakage, especially the more recent ones, have included thermocycling in the experimental method (Kidd, 1976; Glyn Jones, Grieve & Harrington, 1979; Grieve,
Saunders & Alani, 1993; Rossomando & Wendt, 1995). Nelsen, Wolcott, and Paffenbarger (1952) were probably the first to demonstrate marginal percolation due to thermal changes. It was pointed out that marginal percolation was caused by a difference in the coefficient of thermal expansion between the dental tissues and the restorative material and by thermal expansion of fluids occupying the crevice between tooth and restoration. Kidd (l 976) concluded that it was obvious that some form of thermal stressing should be incorporated in microleakage studies.
The temperatures used for in vitro thermocycling have ranged from 0 °C to 68 °C (Shortall, 1982).
Many investigators used temperatures of 15 °C and 45 °C for their thermocycling (Peterson, Phillips & Swartz, 1966; Guzman, Swartz & Phillips, 1969; Glyn Jones & others, 1979). These figures were based upon in vivo work carried out by the authors using thermocouples to measure the temperature on the surface of the tooth during imbibition of hot and cold drinks. Others utilized temperature changes from 4 °C to 60 °C (Morley & Stockwell, 1977; Kidd & others, 1978), while some cycled between 5°C and 55°C (Grieve & others, 1993). Harper and others (1980) suggested that the temperature variation in the mouth was quite small.
19 The time used for the alternate immersion of specimens in hot and cold solutions has ranged between 10 seconds (Saunders & others, 1990), 15 seconds (Retief, 1989; Mandras, Retief &
Russell, 1991), 30 seconds (Darbyshire, Messer & Douglas, 1988; Moore & Vann, 1988), 60 seconds (Welsh & Hembree, 1985; Fayyad & Shortall, 1987), and 120 seconds (Momoi & others, 1990). Causton and others (1984) showed that cycling regimes using a short dwell time may be more realistic clinically..
Gale et al (1999)22 made an assessment of reports describing temperature changes of teeth in vivo followed by an analysis of 130 studies of laboratory thermal cycling of teeth selected from 25 journals. There is no evidence of the number of cycles likely to be experienced in vivo was found and this requires investigation, but a provisional estimate of approximately 10, 000 cycles per year is suggested. Thermal stressing of restoration interfaces is only of value when the initial bond is already known to be reliable.
Adrian et al (2002)3 determined the influences of storage, thermal and load cycling as well as combinations of these treatment procedures on the microleakage patterns of a new ‘condensable’
silver reinforced restorative glass–ionomer cement (Shofu Hi‐Dense). Class II preparations with gingival margins in dentine were made on 50 freshly extracted, non‐carious molar teeth and restored with Shofu Hi‐Dense according to the manufacturer’s instructions. The restorations were subsequently stored for 1 week, finished and randomly assigned into five groups of 10 and treated as follows: Group 1 ‐ control (uncycled); Group 2 ‐ thermocycled; Group 3 ‐ mechanically load cycled; Group 4 ‐ three months storage, uncycled; Group 5 ‐ three months storage, thermal and load cycled. The storage medium throughout the experiment was artificial saliva at 37°C. All treatment procedures had no significant influence on microleakage at the enamel–cement interface.
These treatment modalities, however, resulted in a significant increase in leakage at the dentine–
cement interface. With the exception of the 1 week storage, uncycled group, the dentine–cement interface had significantly greater leakage than the enamel–cement interface.
20 Ernst et al (2004)13 examined the interproximal temperature characteristics created in the space of all teeth in vivo with thermal alternating stress, and therefore to validate the in vitro standardized thermal alternating stress of 5-55 degrees C. Fifteen study participants with healthy teeth were used to determine the temperature in each inter-dental space, resulting from hot/cold provocation in the upper and lower jaw, from the central incisor to the second molars. This was performed by a thermal element (cable sensor GTF 300, Greisinger Electronic GmbH, Regenstauf, Germany). The temperature sensor was attached with dental floss into the interproximal space and the temperature was recorded by the computer. The participants in the pilot test had to state when they were able to sip an 85 degrees C hot drink. That particular temperature value was taken for hot provocation as maximum temperature reference. Cold ice water (0 degrees C) was used for cold provocation as minimum temperature reference. The study participants were to start with hot provocation,
followed by cold provocation. This cycle was repeated at least once with an individual dwell time.
The highest recorded approximal space temperature was 52.8 degrees C in the lower jaw, between the first and the second premolar. The lowest temperature of 13.7 degrees C was recorded in two participants in the upper jaw, between the 1st and 2nd incisor, and between the two central incisors. The mean of the maximum temperatures was 43.8+/-3.7 degrees C, and the mean of the minimum temperatures 24.2+/-4.6 degrees C. The mean initial temperature was 35.2+/-1.3 degrees C. None of the recordings reached either the upper threshold (55 degrees C) or the lower threshold (5 degrees C). This study showed that the actual thermal stress in the interproximal space of teeth is slightly lower than the one used in in vitro examinations. For class II cavities, most of the alternating temperature stress limits selected at 5-55 degrees C cover the actually occurring temperature interval quite well.
Shanthala et al(2013)67 determined the effect of thermocycling on the fracture toughness and hardness of 5 core build up materials. DPI alloy, Miracle-mix, Vitremer, Fuji II LC and Photocore.
Ten specimens of each material were thermocycled for 2000 cycles and the other 5 specimens were not thermocycled (non-thermocycled group). All specimens were subjected to 3-point
21 bending in a universal testing machine. The load at fracture was recorded and the fracture
toughness (K IC ) was calculated. Vickers hardness test was conducted on the thermocycled and non-thermocycled group specimens. Photocore had the highest mean K IC in both thermocycled and non-thermocycled groups. Miracle-mix demonstrated the lowest mean fracture toughness (K IC ) for both thermocycled and non-thermocycled groups. By applying Mann Whitney 'U' test the Vickers hardness value in all materials used in the study is highly superior in non-
thermocycled group as compared to thermocycled group (P < 0.01). Non-thermocycled Photocore showed highest hardness values of 87.93. Vitremer had lowest hardness of 40.48 in thermocycled group. It was concluded that Thermocycling process negatively affected the fracture toughness and hardness of the core build-up materials.
Kong et al (2015)80 evaluated the long‐term influence of the shear bond strength (SBS) on glass‐ionomer cement (GIC) to Er:YAG‐irradiated and bur‐prepared enamel and Influence of thermocycling on shear bond strength of glass ionomer cement to Er:YAG laser‐prepared enamel.
Samples were divided into five groups, according to surface treatments: bur preparation (B); bur preparation, etching with 37% phosphoric acid (BA); laser preparation (L); laser preparation, etching with 37% phosphoric acid (LA); laser preparation, twice irradiating with laser at low (150 mJ, 10 Hz; water spray 10 ml/min) (LL). Samples were subdivided according to the number of thermo‐cycles (TCs)‐500 TCs, 1,000 TCs, 3,000 TCs, and 5,000 TCs. The SBS between GIC and enamel was measured using a universal testing machine; failure patterns were analyzed with stereomicroscope. The enamel surfaces and the patterns of the junction between GIC and enamel were observed by scanning electronic microscopy (SEM). The SBS of L group was higher than that for the B group (P < 0.05). The failure mode analysis demonstrated a cohesive failure within the cement in BA and LA groups, but the SBS of LA group was higher than that for the BA group (P < 0.05). LL had a similar effect on SBS compared with LA. 37% phosphoric acid had greatly increased SBS of GIC to enamel (P < 0.05). The SBS was significantly affected by thermocycling
22 (TC) (P < 0.05). The results of the current study revealed that Thermocycling had a significant effect on SBS of GIC to enamel. There was a significant downward trend especially after 500 TCs.
Then, the SBS slowly declined and tended to stabilized with TCs increase. Results also showed that Er:YAG irradiated significantly increased the SBS on GIC to enamel than bur prepared enamel. In addition, 37% phosphoric acid pretreated also significantly increased the SBS on GIC to enamel.
Vasudev ballal (2019)54 evaluated the effect of thermocycling on shear bond strength of Fuji IX glass ionomer cement and a novel glass ionomer cement (Ketac Universal) to dentin. There was no statistical difference in the shear bond strength of Ketac Universal and Fuji IX glass ionomer cement before thermocycling. However, after thermocycling, Fuji IX GIC showed significantly higher shear bond strength. Thermocycling affected the shear bond strength of the two glass ionomer cements tested. Fuji IX demonstrated significantly higher shear bond strength as compared to Ketac Universal when subjected to thermocycling.
MICROLEAKAGE ASSESSMENT METHODS
Contemporary Methods includes Dye Penetration, Chemical Tracers, Radioactive Tracers, Bacteria, Air Pressure, Artificial Caries, Neutron Activation Analysis, Electrical Conductivity.
Three-Dimensional Methods includes Confocal Laser Scanning Microscope, Optical Coherence Tomography, Micro-Computed Tomography, Scanning Electron Microscopy.
SCANNING ELECTRON MICROSCOPY
Electron Microscopes are scientific devices to examine objects on a very fine scale yielding the information about the topography, morphology, composition and crystallographic information.
Electron Microscopy permits the scanning of images at high magnification (50x – 10.000x).
The use of scanning electron microscopy (SEM) provides a means of direct visual observation of the adaptation of restorative materials to cavity margins because of its high magnification and
23 depth of focus (Boyde & Knight, 1969). The technique is limited to the evaluation of teeth outside the oral environment and is not oriented to diffusion and penetration as are most other studies (Going, 1972). However, many workers have used SEM to measure gap formation that occurred between the restorations and walls and floor of the preparation (Davila, Gwinnett & Robles, 1986, 1988; Van Dijken & Horsted, 1989).
Hallett et al (1993)28 compared Microleakage of two resin-modified glass ionomer cement (GIC) restorative materials with that of two conventional GIC restorative materials-Fuji II LC, Fuji II, Photac Fil, Ketac Fil in a class v cavity. The occlusal margin was in enamel and the gingival margin was in dentin/cementum. All were restored according to the manufacturers' instructions.
After thermocycling, 30 teeth were placed in 2% basic fuchsin dye for 24 h, sectioned and viewed with a stereomicroscope to assess microleakage. The other 15 teeth were sectioned, replicated and prepared for marginal gap evaluation using a SEM. The resin-modified GIC restorative materials did not consistently seal better than the conventional GIC formulations. In Group I, Fuji IX had a significantly higher resistance to the microleakage test at the occlusal wall compared with FUJI II LC . Although the gingival wall scores for FUJI IX were lower than FUJI II LC , this difference was not significant. PhotacFill sealed significantly more effectively at the occlusal and gingival walls compared with KetacFill. Photacfill showed significantly less microleakage against enamel and dentin/cementum compared to the conventional GIC
Hosoyo et al (1998)35 evaluated the bonding mechanism to enamel and dentin of two chemically- cured restorative glass ionomer cements. Ketac-Molar Aplicap (after conditioned with Ketac- Conditioner) and Fuji IX GP (after conditioned with Cavity Conditioner) was applied on the enamel and dentin. Ketac-Molar Aplicap was coated with Ketac-Glaze and Fuji IX GP with GC Fuji Varnish. After 24-hr immersion in water, bonding interfaces were coated with gold-palladium and observed under the SEM. For both Ketac-Molar Aplicap and Fuji IX GP, an intimate
24 adaptation between the material and the enamel was observed. Both materials bonded to dentin without gap formation.
Glasspoole et al (2002)19 evaluated the effect of various surface treatments on the bond strength of several glass ionomers to enamel, and to examine the resulting bond interface. (1) no pretreatment, (2) Vitremer primer, (3) 10% polyacrylic acid or (4) 35% phosphoric acid. A conventional glass ionomer fuji ll and two resin-modified glass ionomers (RMGI's) fuji ll LC and vitremer were bonded to the pretreated enamel surfaces, stored in water for 24h and shear bond strengths
measured. Transverse sections of similarly prepared samples were etched with phosphoric acid for 60s to partially remove enamel and expose the enamel/glass-ionomer interface. The interface morphology was examined by SEM. Polyacrylic acid and phosphoric acid conditioning resulted in significantly increased bond strength to enamel for all three glass ionomer materials, compared to no pretreatment (p<0.01). Light-cured bond strengths were in most cases, significantly greater than when self-cured (p<0.01). Examination of the bonded interfaces revealed the presence of polymer tags in the enamel conditioned with polyacrylic acid and phosphoric acid.
Katleen et al (2008)39 investigated microleakage in class V cavities following restoration with conventional glass-ionomer cements (CGICs) or resin-modified glass-ionomer cements
(RMGICs), following Er:YAG laser or conventional preparation.Three hundred and twenty class V cavities were assigned to four groups: those in groups A and B were prepared using an Er:YAG laser, and those in groups C and D were conventionally prepared. In groups B and D the surface was additionally conditioned with cavity conditioner. Each group was subdivided according to the GIC used: groups 1 (Fuji II), 2 (Fuji IX), 3 (Fuji II LC) and 4 (Fuji VIII). After thermocycling, the specimens were immersed in a 2% methylene blue solution, sectioned oro-facially, and analyzed for leakage. The effect of the conditioner was analyzed using a scanning electron microscope (SEM).Significant differences between occlusal and gingival margins were found in all groups except B4, D3, and D4. Comparison of preparation methods (groups A–D) revealed significant differences at the occlusal margin in groups 1 and 3, but in all groups at the gingival margin. Laser
25 preparation without conditioning allowed more leakage. Comparison of filling materials (groups 1–4) revealed significant differences in groups B and C at the occlusal margin, and in all groups at the gingival margin. In these groups, laser-prepared cavities (with or without conditioning)
restored with Fuji II LC and Fuji VIII showed the least leakage at both margins. RMGICs allowed less microleakage than CGICs. Complete marginal sealing was not achieved and conditioning is recommended.
Jiang et al (2014)80 examined the effects of Er:YAG laser in improving the binding of the glass ionomer cement (GIC) to enamel surfaces. Briefly, 77 human premolar and molar teeth free of visible caries were used from the study and treated with different methods, including regular abrasion with diamond saw (Bur), 10 polyacrylic acid, 37% phosphoric acid, and/or Er:YAG laser.
The shear bond strength (SBS) between GIC and enamel surfaces were measured; the patterns of the junction between GIC and enamel were observed by scanning electron microscopy (SEM);
failure patterns were analyzed with stereomicroscope to determine the adhesive and cohesive patterns of the fracture. The results showed that the treatment of Er:YAG laser resulted in a higher SBS values than that of bur. The use of 10% polyacrylic acid could improve the GIC bonding to the bur-prepared enamel, but not for laser-prepared enamel surface. However, the treatment with 37% phosphoric acid increased the SBS dramatically both in bur-prepared and laser-prepared groups. The failure mode analysis and SEM observation demonstrated a cohesive failure within the cement. In conclusion, the treatment of Er:YAG laser was beneficial for the adhesion of GIC to enamel.
Rengo et al (2015) compared in Class V restorations marginal leakage measurements obtained with microcomputed tomography (micro-CT) and scanning electron microscopy (SEM)
observation. No statistically significant difference in leakage scores emerged between micro-CT and SEM.
26 MATERIALS AND METHODS
ARMAMENTARIUM:
40 Freshly Extracted Single-Rooted Human mandibular Premolars
High Speed Airotor Handpiece ( NSK Pana Air HandPiece, Japan)
Straight Fissure Diamond Points (SF - 11)
William’s graduated Probe
Paper pad
Agate Spatula
Plastic instrument
Thermocycling water bath
Low speed Diamond Disc with Water Coolant.
Distilled water
Scanning Electron Microscope (Hitachi Co. Japan)
27 EXPERIMENTAL MATERIALS:
S.NO NAME COMPOSITION
1 FUJI IX( GC
CORPORATION, JAPAN)
Powder: fluoro aluminosilicate glass
Liquid: polyacrylic acid, tartaric acid
2
ZIRCONOMER
IMPROVED(SHOFU INC.
JAPAN)
Powder: fluoroaumino glass powder, nano sized zirconia filler Liquid: polyacrylic acid, tartaric acid, deionized water
3 RIVA SELF CURE (SDI, AUSTRALIA)
Powder: fluoroalumino silicate glass, Bioactive ion glass filler Liquid: polyacrylic acid, tartaric acid
4 XTRACEM-S (MEDICEPT
DENTAL, UK)
Powder: fluoro alumina silicate glass, nano silver filler
Liquid: polyacrylic acid, tartaric acid
