Dr. PRAKASH LOKHANDE

RAJIV GANDHI UNIVERSITY OF HEALTH SCIENCES, BANGALORE, KARNATAKA

“COMPARATIVE EVALUATION OF MICROHARDNESS OF

CORONAL

DENTIN WITH RESIN MODIFIED GLASS IONOMER AND

COMPOMER IN CLASS V RESTORATION - AN INVITRO STUDY”

By

Dr. PRAKASH LOKHANDE

Dissertation Submitted to the Rajiv Gandhi University of Health Sciences, Karnataka,

Bangalore.

In partial fulfillment of the requirements for the degree of

M.D.S (Master of Dental Surgery)

in

Conservative Dentistry and Endodontics

Under the guidance of

Dr. Mangala T.M.

Department Of Conservative Dentistry And Endodontics BAPUJI DENTAL COLLEGE & HOSPITAL

DAVANGERE – 577 004, KARNATAKA 2006 - 2009

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ACKNOWLEDGEMENT

At the very onset I would like to convey my heartful gratitude to my parents

who have been the backbone in every aspect of my life. This thesis would not have

been possible without their blessings and support.

Its great honor to express my gratitude to my guide Dr. Mangala T.M.M.D.S.

professor, Department of Conservative Dentistry and Endodontics, Bapuji Dental

College and Hospital, Davangere. She has given me excellent guidance all through in

my academics as well as for my thesis. Her professionalism and knowledge has

always inspired me during the course of my study. I am deeply indebted to her kind

concern and being a sincere advisor which has put me on the right track.

It is with humble sense of gratitude that I thankfully acknowledge my

esteemed Professor and Head Dr. Mallikarjun Goud. K.M.D.S. Department of

Conservative Dentistry and Endodontics , Bapuji Dental College and Hospital,

Davangere, who made this formidable task possible. I shall always be grateful to him

for his sincere advice and timely suggestions.

I can’t forget Dr. Girija Sajjan M.D.S. our former Head of the Department.

She was always kind and supportive during the study period in the College.

I wish to thank Dr. Basavanna M.D.S. Dr. Sophia Thakur M.D.S. Dr. Arvind

Shenoy.M.D.S. Dr.Satya Narayanan K.M.D.S. Dr. Subhash T.S. M.D.S.

Dr. Kanchan M.D.S. Department of Conservative Dentistry and Endodontics, for

providing their support and guidance during the course of my study.

6VI

It is with great honor and pleasure that I will take this opportunity to thank our

beloved Principal, Dr. K. Sadashiva Shetty, Bapuji Dental College and Hospital,

Davangere, for facilitating my study.

I sincerely thank our Chairman, Late Sri I.P. Vishwaradhya. M.Com. for the

providing an opportunity to pursue this course.

I am deeply indebted to Mr. Shyam Sundar, Department of Mechanical

Engineering, Indian Institute of Science (IISC), Bangalore, for providing me that

opportunity to use the microhardness equipment.

I thank to Mr. Ganesh (Chaithanya Studio), for his excellent photography in

helping me record various photos.

I am grateful to Mr. Thomas & Mrs. Rashika Thomas (THOMAS

COMPUTERS) for helping me to shape out the manuscript and bring out this

dissertation in a neat and coherent manner.

I thank my batchmates Dr. Arun, Dr. Roopa, Dr. Fayaz, Dr. Nikhil and Dr.

Ritesh for extending their valuable help and guidance during the study period.

I thank to all my supportive seniors and lovable juniors for their flawless

support.

Not to forget my seniors Dr. Hemadri, Dr. Amit, Dr. Manjunath, Dr.

Harikiran, Dr. Purushotham for their invaluable encouragement embedded with

humor.

7VII

I extend my sincere gratitude to Netravati B. Yashodhamma H.B.,

Anupama Patil, Umadevi B.T., the paradental staff and not to forget Rudramma

G.C., Annapurnamma and Veeranna J. the attenders.

I immensely thank to my lovable, caring would-be Miss Preethi, for her kind

advice and moral support in my study period.

I can’t forget my elder brother Mr. Santosh N.L. and younger sister

Poornima for their good wishes and prayers

Finally I surrender myself to “Almighty God” for all his divine grace and

fulfilling my dreams.

Date :

Place : Davangere. Dr. Prakash Lokhande

8VII

ABSTRACT

Background and Objective :

Microhardness is one of the most important characteristic for comparative

study of dental biomaterials. Fluoride promotes remineralisation of dental hard tissue

and as we know Glass-ionomer Cement are well known fluoride releasing restorative

material. This study throws a light on, changes taking place in microhardness of

dentin adjacent to Resin modified glass-ionomer (RMGI) or compomer. The aim of

this study is to compare the microhardness of coronal dentin over class V cavities

restored with Resin modified glass-ionomer (RMGI) restorative material and

compomer.

Methodology ;

Thirty extracted human permanent molars with class V caries were taken for

the study. After storing in normal saline, standardized class V cavities were prepared

for each group (n=10). Group I : Without restoration, Group II : Restored with Resin

modified glass-ionomer (RMGI), Group III : Restored with compomer. After ten

days the teeth were embedded in acrylic resin to avoid displacement of restoration

during sectioning. Later dentinal sections of 2 mm were obtained at a level of cavity

floor and roof (cross section) by means of diamond blade. The specimen are

ground, flat and polished with abrasive paper (grit 60-100).

Viker’s microhardness (VHN) measurements were performed by using

Digital Microhardness Tester (Zwick / Roell) at 10th, 20th and 30th day under a

load of 25 grams for 15 seconds at a distance of 100 µm, 200 µm and 300 µm

9IX

from cavity floor. The statistical significance of hardness was analyzed by

one-way ANOVA and Post-Hoc Tukey test. (P<0.05).

Conclusion and Interpretation :

The present invitro study showed an increase in microhardness of dentin

adjacent to Resin-modified glass-ionomer (RMGI) as compared to compomer,

because of its higher fluoride release and remeniralising capacity.

Key Words : Vicker’s Microhadness (VHN); Class V cavity;RMGI;

Compomer; Remineralisation.

10X

LIST OF ABBREVIATIONS USED

APF : Acidulated Phosphate Fluoride

Ca2+ : Calcium

CT : Computer Tomography

DEJ : Dentino Enamel Junction

FTIR : Fourier Transform Infrared Spectroscopy

G.I.C. : Glass Ionomer Cement

g : Grams

μm : Micrometer

μl : Micro liter

MPa : Mega Pascal

mm : Millimeter

mm2 : Square Millimeter

N : Newton

PH : Figure for expressing acidity and alkalinity

PO4-3 : Phosphate

RMGI : Resin-Modified Glass Ionomer

RPD : Removable Partial Denture

SnF2 : Stannous Fluoride

SEM : Scanning Electron Microscopy

VHN : Vicker’s Microhardness

11XI

TABLE OF CONTENTS

Page No.

1. INTRODUCTION 1

2. OBJECTIVES 3

3. REVIEW OF LITERATURE 4

4. METHODOLOGY 16

5. RESULTS 24

6. DISCUSSION 34

7. CONCLUSION 42

8. SUMMARY 43

9. BIBLIOGRAPHY 44

10. ANNEXURE 50

12XII

LIST OF TABLES

Sl. No. Tables Page

1 Vicker’s Microhardness (VHN) of coronal dentin at 100μm from

cavity floor for group I, II and III at 10th, 20th and 30th day

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cavity floor for group I, II and III at 10th, 20th and 30th day.

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LIST OF GRAPHS

Sl. No. Graphs Page

1 Vicker’s Microhardness (VHN) of coronal dentin at

100μm from cavity floor for group I, II and III at

10th, 20th and 30th day

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10th, 20th and 30th day

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10th, 20th and 30th day.

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13XIII

LIST OF FIGURES

Sl. No. Figures Page No.

1 Materials 20

2 Instruments 20

3a Light curing Unit (3M,ESPE) 21

3b Digital Micro Hardness Tester (Zwick / Roell) 21

4 Extracted Teeth with class V caries 22

6 After Class V cavity Preparation 22

6 After Restoration 23

7 After Sectioning 23

14XIV

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Dedicated

To My

Beloved Parents &

Lord Almighty

Introduction

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Introduction

INTRODUCTION

Knowledge of the hardness of material and dental structure is a valuable

information to the dentist. Measuring microhardness makes it possible to evaluate the

mineral content of the tissues, and to assess whether there was loss of mineral due to

dissolution of the inorganic part, as it occurs during carious process, and also to

quantify the gain in density through a process of ion incorporation (remineralisation).

Hardness is the resistance of a material to plastic deformity typically measured

under an indentation load. There are various tests to check hardness: Barcol, Brinell ,

Rockwell , Shore, Vickers and Knoop. Most commonly used are Brinell, Rockwell

which are macrohardness tests and Vickers and Knoop which are microhardness tests.

Both Knoop and Vickers tests employ loads less than 9.8 N. The resulting

indentations are small and are limited to a depth of less than 19 μm. Hence they are

capable of measuring the hardness in small regions of thin objects. 1 Hardness has

been associated with relative infectivity of carious dentin, helping the dentist to

distinguish, between either infected (soft) or affected(hard) dentin..2

Microhardness is one of the most important physical characteristic for a

comparative study of dental materials. 3.

To know the microhardness of each and every material and that of the tooth

structure is of utmost importance. The microhardness of healthy dentin, carious

dentin and dentin overlying a restorative material varies.

Dental caries is an infectious disease, which causes the local destruction of the

tooth structure of hard tissues and it is associated to diet, microorganisms

accumulation and salivary conditions. Due to frequent ion loss during demineralizing

process, there will be decrease in microhardness.

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Introduction

When a pH of the oral environment reaches a critical value of 5.5,

subsaturation of Ca2+ & PO4-3 ions occurs. The tendency is thus, the loss of ions from

the teeth to the environment, which is called demineralisation.

When the pH becomes higher than 5.5, through the buffering action of the

saliva, there is a Ca2+ & PO4-3 ions supersaturation in the environment. In this

situation, the tendency is for the teeth to incorporate ions, which is called

remineralisation 4.

Fluoride and other ions have been detected in high concentrations in the dentin

adjacent to GIC restoration and by placing GIC onto demineralised dentin, it resulted

in hypermineralisation of the dentin.5

RMGI cements and polyacid modified resin composites (compomers) claim to

improve the mechanical properties, while retaining the esthetics, adhesion and

enhancing fluoride releasing properties of conventional G.I.C’s. 6

The advantage of using RMGI in this study is, it is less technique sensitive,

fluoride release, stronger than traditional glass ionomer, light cured and finished at the

time of placement.

The advantage of using compomer in this study is, it possesses a combination

of characteristics of both composite and glass ionomer (fluoride release) 7.

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Objectives

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Objectives

OBJECTIVES

1. To check microhardness, (VHN) Vicker Hardness of coronal dentin in class V

restoration filled with resin modified glass ionomer restorative material.

2. To check microhrdness (VHN) Vicker hardness of coronal dentin in class V

restoration filled with compomer.

3. To compare microhardness (VHN) Vicker Hardness of coronal dentin in class

V restoration filled with resin modified glass ionomer restorative material and

compomer.

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Review of Literature

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REVIEW OF LITERATURE

The purpose of this study was to investigate the relationship between the

microhardness and calcium content in sound and decalcified enamel. Twenty freshly

extracted human caries-free permanent incisors and premolars and twenty incisor

bovine teeth were selected for this study. They were then subjected to slow

decalcification and etching. Microhardness measurements show that surface layer

covering the lesion possess a significantly greater hardness value than within the

lesion. In the etched enamel, microhardness and calcium content were at lower level

as compared to that of unetched enamel. The hardness in the etched enamel was

reduced to approximately 50% of its original value. This study shows that etching

reduces microhardness of enamel. 8

The purpose of this study was to evaluate the effect of various fluoride

treatments on microhardness of dentin. Fifty mid coronal dentin specimens of 2mm

thick, which were sectioned transversally, were taken from extracted human

premolars. They were then mounted and polished, then subjected to Knoop hardness

test with load of 500 g with help of Tukon hardness tester. Ten specimens was then

subjected for two minutes treatment period with each solution(1) Deionised water pH7

(2) Acidulated phosphate fluoride (APF) solution at pH3.0 containing 0.31% fluoride

(3) APF with PH 4.0(4) sequential treatment with 0.31% F – APF PH4.0 followed by

SnF2. After treatment they were subjected to microhardness testing. The results

showed that, sequential treatment with APF pH4.0 followed by SnF2 produced

significant hardening of dentin.9

The purpose of this study was to determine the relationship between dentin

microhardness and tubule density in normal human permanent teeth. Unerupted third

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molars were extracted and stored in phosphate buffered saline. The roots were

sectioned from the crown at the level of cemento-enamel junction. After removing the

pulpal soft tissue with an endodontic broach, 0.1µl of 0.5% tryptan blue or Congo

red dye was placed in the tip of the pulp horn. The dye was allowed to diffuse to the

dentin surfaces, thereby marking a group of tubules from the pulp to the surface. After

the dye had completely diffused through the tubules, the dentin surface were

polished. Microhardness measurements were only made within the dyed zone of

dentin using a Knoop indenter microhardness tester. The results revealed that there is

a highly stastically significant inverse correlation between microhardness and

tubular density. Tubular density increased as the pulp chamber was approached. This

was associated with a decrease in microhardness of dentin, presumably due to a

decrease in the amount of intra-tubular dentin and an increase in individual tubular

diameter. 10

The aim of this study was to examine the time dependency of microhardness

indentations in human and bovine dentin and to make a comparision between these

indentations and similar indentation set in human enamel. Microhardness indentations

were made perpendicular to the sound as well as in demineralised dentin. The

indentations were made with Leitz miniload microhardness tester with a Knoop

diamond indenter at load of 500gram for 10 seconds. From microradiographic

analysis of the samples it was found that there was no correlation between mineral

content and microhardness. The results indicated that for microhardness indentation

measurements in human demineralised dentin, the time dependency should be taken

into account. In human dentin no direct relation was found between hardness and the

mineral content 11.

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The purpose of this study was to evaluate invitro effect of glass-ionomer

cement restoration on enamel subjected to a demineralization and remineralisation

model. Expieremental secondary caries was induced around cavities restored with

glass-ionomer cement and composite resin. The effect of these materials was assessed

by microhardness profile. The result showed that G.I.C. has potential value as a

restorative material for the prevention or reversal of caries in enamel adjacent to

restoration, even in situation of high cariogenic challenge. 12

The purpose of this study was to examine intermediate layer between a glass-

ionomer restoration and dentin with the help of Scanning Electron Microscopy (SEM)

and Fourier Transform Infrared Spectroscopy (FTIR). SEM analysis of this study

showed that there was strong bonding between G.I.C and dentin and formation of an

intermediate layer between them. FTIR spectroscopy showed that the intermediate

layer is composed primarily of mineral fluoridate carbonatoapatite. This mineral

presence between dentin and restoration provide high resistence to secondary caries

and may be of clinical importance. 13

The study was done to determine whether glass-ionomer cement could

contribute to the remineralisation of carious lesion in dentin. Small cylindrical

specimens were prepared from freshly extracted bovine incisors, which had incipient

caries-like lesions in the remaining tissue. The control group were filled with

amalgam or composite. The experimental group were filled with GIC. They were

then placed contralaterally in buccal surface of removable partial denture (RPD) that

were worn for 12 weeks experimental period. They were sectioned and analysed by

microradiography. The results showed that specimens with GIC restorations exhibited

hypermineralization in the dentin adjacent to the filling. This study shows that, there

6


is significant remineralisation potential exerted by fluoride releasing G.I.C. restorative

materials. 14

The aim of this study was to investigate the influence of RMGI on carious

dentine that remains under restorations, when compared to amalgam. Forty patients

with occlusal dentinal caries on molars were taken for the study. After removing the

enamel caries, carious dentin was sampled just beneath the DEJ using a round bur.

Later restored with RMGI or amalgam. Microbiological analysis was done for

determining total viable count (TVC), mutans streptococci (MS) and lactobacilli.

After six months of period, molars were reopened and samples were taken. Then the

cavities were restored with permanent restorations after complete removal of caries.

RMGI showed a significantly larger decrease in count of mutans streptococci and

lactobacilli than amalgam. 15

The study was done to correlate Knoop and triangular hardness numbers by

measuring the microhardness of invitro caries inhibited and demineralised dentin

adjacent to a conventional and two resin-modified glass ionomer cements. Box

shaped cavity measuring 3mm long, 2mm wide and 1.5mm deep were prepared on

bovine root dentin. They were then restored with either Fuji II which is conventional

glass-iononer, Fuji II LC or Vitremer which is RMGI cements. The specimens were

then subjected to decalafication. Knoop and triangular microhardness indentation

were performed perpendicular to the surface and parallel to the cavity wall, in the

demineralised and inhibition zone. The microhardness of inhibition zone created by

conventional glass-ionomer was significantly higher than RMGI cements. This study

concludes that G.I.C were effective in producing an acid-resistant layer.

Microhardness and intensity of acid-resistant layer were material dependent. 16

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The main purpose of this study was to evaluate the Calcium, Strontium,

Aluminium, Sodium and Fluoride release profiles from three conventionalG.I.C.

(Ketac Cem, Ketac Bond, Fuji II) and RMGI(Fuji II LC improved). Strontium was

released only from Fuji II which is conventional glass-ionomer and Fuji II LC which

is RMGI, while calcium was released from conventional G.I.C . All four materials

released aluminium and sodium. The study concludes that calcium and strontium

released from G.I.C. may complement fluoride in promoting remineralization. 17

The main purpose of this study was to measure the compressive strength,

flexural strength, microhardnes and surface roughness of compomers and compare the

value with RMGI and resin composite. The study revealed that,RMGI showed lesser

values of compressive strength, flexural strength, microhardness as compared to

compomer and resin composite. Resin composite showed highest values. 18

The purpose of this study was to measure the microhardness values of carious

deciduous dentin and to compare with transparent dentin and sound dentin. Seven

extracted or exfoliated deciduous anterior tooth with dentinal caries on one or both

proximal surface were taken and stored in physiologic saline solution. The sectioned

dehydrated and dried specimens were subjected to miniload 2TM microhardness

tester with Knoop indenter using a load of 15 gram for 15 seconds. The results

showed that microhardness values under caries is significantly lower as compared to

outer and middle region of dentin. There was decrease in microhardness from DEJ to

pulp chamber wall except under caries 19.

The purpose of this study was to compare compomer and RMGI clinically for

marginal adaptation, marginal discoloration , secondary caries, anatomic form, color

match and retention, over a period of two-years. Thirty-four pairs of equivalent sized

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abrasion and Abfraction lesion, were restored with compomer and RMGI.

Evaluation of the restorations were clinically done at a baseline, 6,12,18 and 24

months. A significantly higher incidence of failed restorations was found with

compomer. Accordingly to this study RMGI appears to be superior in restoration of

cervical erosion and abfractions 20.

The purpose of this study was to determine tensile properties of human

mineralized dentin. Slabs of dentin were obtained and trimmed to reduce the central

area of the coronal dentin to a cross-sectional area of approximately 0.5mm2 . The

results were statistically analysed. The results revealed that the ultimate tensile

strength of dentin is higher when a load is applied perpendicular to the tubule

orientation (80±13MPa) than when applied parallel to tubule orientation(58±11MPa).

There was a tendency for dentin to be weaker as the number of tubules at the site of

fracture increased, although this relationship was not stastistically significant. It was

concluded that the ultimate tensile strength of dentin is dependent on the tubule

direction. Dentin tends to be weaker as the number of tubules per area increases 21.

The purpose of this study was to evaluate microhardness of dentin after

exposure of two 10% carbamide peroxide bleaching materials and a placebo agent for

42 days of treatment. The microhardness was measured 7 and 14 days post treatment.

The bleaching agents (Opalescence 10% and Rembrandt 10%) and placebo (control)

were applied to the suface of human dentin fragements for 8 hours and then stored in

artificial saliva for the 16 hours each day. Microhardness testing was performed at

baseline, after 8 hours, 7,14,21,28,35 & 42 days of treatment and 7 and 14 days post

treatment. The results demonstrated a decrease in the mean microhardness values of

dentin treated with Opalescence and Rembrandt during treatment period. The

dentinal surfaces treated with placebo exhibited an increase in microhardness values

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post treatment. It was concluded that, bleaching agents decreased dentinal

microhardness over time, but after 14 days in artificial saliva storage at the

completion of treatment, the baseline microhardness value were recovered 22.

The purpose of this study was to determine fluoride release from three glass-

ionomer based restorations following multiple daily exposures to three-topical

fluoride regimens. Thirty two cylindrical specimens, each of a glass-ionomer (Ketac

Fil), RMGI (Photac Fil) and compomer (Dyract AP) were prepared. Each specimens

were subjected to various topical fluoride treatments. Later the specimens were

subjected to demineralising followed by remineralising solution. Fluoride levels were

measured using a digital ion analyzer and fluoride electrode. Flouride release

decreased from day 1 to day 3 regardless of fluoride treatment. By day 7, RMGI

demonstrated both the greatest total fluoride release and the greatest rechargability

followed by conventional G.I.C. and compomer 23.

The purpose of this study was to determine the microhardness of superficial

and deep dentin by means of Knoop and Vickers hardness test, under two different

loads. Twelve dentin discs approximately 2mm thick were obtained from both

superficial and deep dentin by transverse sectioning the crowns of sound, extracted

human third molars. They were then subjected to either Vickers hardness test of load

300g on superficial dentin and 500 g on deep dentin or Knoop hardness test of load

100g on superficial dentin and 50g on deep dentin. The results were subjected to

statistical analysis which showed that, microhardness of dentin was influenced by the

different loads applied for both indentation methods. Knoop hardness values of the

superficial dentin was higher as compared to deep dentin. Conversely, Vickers

hardness values for the superficial and deep dentin was not significantly different. 24

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The purpose of this study was to compare the effect of twelve month storage

period in water on surface microhardness measured in Vickers unit (VH) between

GIC and RMGI group. The Vickers microhardness was measured in three GIC: Ketac

Fil, Ketac Molar and Ketac Silver and three RMGI: photac-Fil, Fuji LC and Vitremer.

The hardness measurements were done with the help of Vickers diamond indenter

with load of 200g for 20 seconds at 1st, 7th, 15th, 80th, 90th, 180th and 365th day. The

results of this study revealed that GIC group except for Ketac sliver showed higher

VH throughout the study period. Among the RMGI group, Vitremer showed higher

microhardness values as compared to photac Fil & Fuji LC. 3

The study was done to evaluate the physiologic remineralisation of artificially

demineralised dentin beneath glass ionomer cements with or without bacterial

contamination. The artificial demineralised dentin were produced on eighty- four

teeth using demineralising solution. Half of the samples were left open to oral cavity

for one week, later all cavities were filled with Fuji IX and Fuji II LC glass ionomer.

Then samples were subjected to nanohardness testing at 3rd, 90th and 360th day. The

results showed that mean nanohardness of three day samples was significantly lower

that 360 day samples. The mean nanohardness of the bacterial contaminated samples

were significantly lower than non-bacterial contaminated samples. 5

The purpose of this study was to determine and compare the surface

microhardness as well as calcium (Ca) and phosphorus (P) mineral content of sound

and carious human enamel and dentin of primary teeth. Sixteen specimens consisting

of eight sound and eight carious primary molars were prepared for microhardness test,

the indentation were made on centre of enamel, dentin below DEJ (superficial dentin)

and deep dentin (above pulp) using a Vickers hardness tester. With help of Energy

Dispersive x-ray microanalysis, calcium (Ca) & phosphorus (P) contents, near the

11


indentation were determined. The results were subjected to statistical analysis which

showed that, microhardnes of enamel and superficial dentin on carious primary teeth

was significantly softer than sound enamel and dentin. The calcium & phosphorus

ratio of sound enamel had higher content of calcium than superficial and deep

dentin 25.

The objective of this study was to evaluate the influence of fluoride

concentration of tooth and dental fluorosis severity on dentin microhardness and

mineralization. One hundred and thirty seven extracted human teeth were collected

from three different places with fluoride water levels of 0.2, 0.7 and 1ppm. There was

positive co-relation between dental fluorosis and dentin microhardness. Genetic and

environmental factors influenced mechanical properties and microhardness of teeth,

while only environmental factors influenced their mineralization 26.

The purpose of this study was to evaluate the marginal and internal adaptation

of restorative system in combination with flowable materials as an intermediate layer

in class V cavities. Thirty caries free extracted human maxillary premolars were

selected. Round shaped class-V cavities with 3mm diameter and 1.5mm deep were

prepared. They were then restored with five restorative materials1) compomer.2)

compositeE, 3) Flowable compomer / composite, 4) composite RF 5) flowable

composite/composite RF. The study revealed that the best marginal adaptation in

dentin was obtained by compomer restoration 27.

The purpose of this study was to evaluate remineralization and fluoride uptake

of demineralised enamel specimens in artificial proximal spaces using a 250ppm

fluoride mouth rinse. Twenty-four volunteers who worn intra-oral appliance were

taken for the study. They were asked to rinse and brush their teeth twice daily with

12


fluoride mouth-rinse and dentifrice respectively, for 28 days. The quantitative light-

induced fluorescence showed a significant remineralising effect of the fluoride mouth

rinse 28.

The purpose of this study was to find the fluoride release and recharge

capabilities and antibacterial properties of fluoride releasing dental restoratives and

their prevention or inhibition of caries development and progression. Results revealed

that the short-term and long term fluoride release from restoratives are related to

their matrices, setting mechanisms and fluoride content and depend on several

environmental conditions. Fluoride releasing materials act as a reservoir and may

increase the fluoride level in saliva, plaque and dental hard tissues. The significance

of this study is that, fluoride releasing materials, predominantly glass-ionomors and

compomers did show cariostatic properties and may effect bacterial metabolism under

simulated cariogenic conditions 29.

The purpose of this study was to compare fluoride release profile of various

restorative materials by using linear regression analysis. Cylindrical specimens were

prepared and immediately placed in artificial saliva, which was replaced at various

times during 6 weeks. Fluoride released was measured by ion selective electrode. The

results were subjected to stastical analysis. The results revealed that, largest fluoride

release was obtained from conventional G.I.C. This was followed by RMGI cement,

compomer and fluoride releasing composite resin. 30

The aim of this invitro study was to evaluate the hardness of dental enamel

after placing a glass-ionomer surface protector cement with increased fluoride

content, a conventional G.I.C and a resin fissure sealent on enamel fissure’s. One

hundred extracted non-carious human molar teeth were divided into five groups. 31

13


a) Group I : Fissure were conditioned with 20% polyacrylic acid and sealed with Fuji

VII. b) Group II : Fissure were conditioned with 20% polyacrylic acid and sealed

with Fuji IX (High Strength G.I.C). c) Group III : Fuji VII. Directly restored to the

fissures. d) Group IV : After etching with 37% orthoposphoric acid the fissures were

sealed with resin-fissure sealent. d) Group V : Untreated (Control). Half of each

group were stored in artificial saliva for one month other half of the group for three

months. Teeth were then sectioned and Vickers hardness was measured. Hardness

values were increased for all the groups at the end of third month. The results

revealed that concentration of fluoride in G.I.C materials seemed to be effective in

increasing the hardness of the adjacent enamel tissue 31.

The purpose of this study was to examine the effects of fluoride combined

with strontium on enamel remineralisation. Sixty caries free premolors which where

demineralised to induce caries like lesions, was taken for the study. Half of each

lesions were untreated and taken as control group. The specimens were divided into

fluoride and strontium-fluoride treatment groups. These groups were exposed to

remineralising solutions. With the help of contact microradiography, the level of

remineralisation was determined. The results showed that fluoride and strontium

showed a synergistic effect on remineralization 32.

The purpose of this study was to evaluate remineralisation of incipient

artificial interproximal caries-like lesions adjacent to the restorations: highly filled

G.I.C,. compomer, RMGI and resin-composite. Proximal restorations were simulated

by placing tooth specimens and various glass-ionomer cements in closed containers

with artificial saliva at 370C and PH7.0 for 30 days. With the help of micro-CT

14


scanner, tomographic images were obtained at 90,180,270 days. Density measuring

software was used to calculate microdensity of artificial caries and compare that with

other groups to evaluate remineralisation. G.I.C. showed increased density as time

lapsed. The clinical significance of this invitro study showed that glass-ionomer

restorations can remineralise adjacent tooth structure .33

15

Methodology

16

Methodology

METHODOLOGY

The present invitro study was conducted in the post graduate, Department of

Conservative Dentistry and Endodontics, Bapuji Dental College and Hospital,

Davangere, Karnataka.

Selection of Teeth:

Thirty freshly extracted human permanent molars were collected from the

Department of Oral and Maxillofacial Surgery, Bapuji Dental College and Hospital,

Davangere.

Materials used:

1) Resin Modified glass Ionomer (RMGI) [Vitremer (3M,ESPE)]

2) Compomer (Dyract Flow, Dentsply)

3) Acrylic Resin(DPI-RR Cold cure)

4) Normal saline

5) Abrasive paper (60-100 grit)

Instruments used:

1) Contra angle hand piece (NKS, Japan)

2) Carbide burs (Round/Straight)

3) Explorer

4) Plastic Filling instrument

5) Diamond blade

Equipment used:

1. Light curing unit( 3M,ESPE)

2. Digital Microhardness Tester (Zwick / Roell)

16

Methodology

METHODOLOGY

Thirty freshly extracted human permanent molars with class-V carious

infected lesion, on either buccal or lingual surface were selected. The specimens were

cleaned free of debris and calculus and were stored in normal saline. The teeth with

cavity depth extending more than 2mm, age of the patient, caries involving pulp,

cracks, abrasion erosion, abfraction and tooth with occlusal caries were excluded

from the study.

Caries excavation was done with round carbide bur followed by straight

carbide bur. The cavity preparation for all groups were standardized, with occluso-

cervical width of 2mm, mesio-distal width of 5mm and depth of 2mm from the cavity

margins.. Complete removal of caries was evaluated by visual evidence like

cavitations, surface roughness, opacification and discoloration.

Group I : Control Group : 10 Class V prepared cavity without restoration

Group II : 10 class V prepared cavity, filled with RMGI [Vitremer (3M,ESPE)]

Group III :10 class V prepared cavity, filled with compomer [Dyract Flow

(Denstply)]

After the completion of the preparation, the cavities were cleaned and dried

with oil free air. Over drying was avoided. Group II and Group III were restored

with RMGI and compomer respectively, according to the manufacturers instructions.

After storing the samples in normal saline for 10 days, the samples blotted dry and

embedded in acrylic resin. Dentinal sections of 2mm are obtained at a level of cavity

floor and roof (cross-section) by means of diamond blade. The specimens are ground,

flat and polished with abrasive paper (grit 60-100).

17

Methodology

Vickers microhardness (VHN) measurements were performed by using Digital

Microhardness tester (Zwick / Roell) at 10th, 20th and 30th day under load of 25 grams

for 15 seconds at a distance of 100 μm, 200μm & 300μm from cavity floor.

18

Methodology

STATISTICAL ANALYSIS

Results are expressed as mean + standard deviation. One way ANOVA was

used for multiple comparisons followed by post Hoc Tukey test for group

comparison.

For all the tests ‘p’ value of 0.05 or less was considered for statistical

significance.

Formula Used :

Mean x = i = 1,2,3,…………10

∑ xi n

∑ (xi-x)2

(n – 1) Standard Deviation , SD =

Variance = SD2

One way ANOVA:

F=

Post – Hoc Tukey’s Test:

Highest Significance Difference (HSD)

HSD = tuk tuk: Table value

Between group variance Within group variance

2s2

n

s2 : Within group variance

n : Sample size

19

20

21

22

23

Results

24

Results

RESULTS

The present invitro study with thirty molars was aimed to comparatively

evaluate the Vicker’s microhardness (VHN) of coronal dentin with Resin Modified

glass ionomer and compomer in class-V restorations.

Thirty molars were divided into three groups, each group consisting of ten

samples. Vicker’s microhardness (VHN) value was measured with digital

microhardness tester (Zwick/Roell) at 10th day. 20th day and 30th day under a load of

25 grams for 15 seconds. The indentations were made at distance of 100μm, 200μm

and 300μm from cavity floor.

Table I: Shows Vicker’s Microhardness (VHN) of coronal dentin at 100μm from


Table II : Shows Vicker’s Microhardness (VHN) of coronal dentin at 200μm from


Table III: Shows Vicker’s Microhardness (VHN) of coronal dentin at 300μm from


24

Results

Table 1:

Group I: Class V cavities without restoration (Control)

Group II: Class V cavities with RMGI restoration

Group III: Class V cavities with Compomer restoration

a) Comparison of Vicker’s Microhardness (VHN) between groups at 10th day at

100 µm from cavity floor.

Group I: 40.9(VHN) Group II 54.2(VHN) Group III 50.7(VHN)

b) Comparison of Vicker’s Microhardness (VHN) between groups at 20th day at


Group I: 37.1(VHN) Group II 57.0(VHN) Group III 50.9VHN)

c) Comparison of Vicker’s Microhardness (VHN) between groups at 30th day at



When microhardness values were compared between the groups, group II

showed more microhardness followed by group III and least with group I.

25

Results

Table II:












Group I: 40.4(VHN) Group II :57.3(VHN) Group III 52.6(VHN)

When microhardness values were compared between the groups, group II

showed more microhardness followed by group III and least with group I.

26

Results

Table III:












Group I: 39.3(VHN) Group II 57.2(VHN) Group III 50.3(VHN

Group II and Group III showed comparably equal microhardness at 300 μm

but more as compared to group I.(Control).

27

Results

Table 1 : Vicker’s Microhardness (VHN) of coronal dentin at 100μm from cavity floor for group I, II and III at 10th, 20th and 30th day

10th Day 20th Day 30th Day

Group I 40.9 + 4.0 37.1 + 2.4 39.6 + 4.9 F = 2.46

P > 0.05 NS

F = 10.9 Group II 54.2 + 2.2 57.0 + 2.3 59.9 + 33

P < 0.01

Group III 50.7 + 2.6 50.9 + 1.8 F = 1.11

52.4 + 3.6 P > 0.05

NS

S

ANOVA ( Analysis Of Variance)

F=52.60 F= 217.0 F= 66.0

P< 0.001 S P < 0.01 S P < 0.01 S

28

Results

Graph 1 : Vicker’s Microhardness (VHN) of coronal dentin at 100μm from


40.9

54.2

50.7

37.1

57

50.9

39.6

59.9

52.4

0

10

20

30

40

50

60

Mea

n M

icro

hard

ness

Val

ue (V

HN

)


Group IGroup IIGroup III

29

Results

Table II : Vicker’s Microhardness (VHN) of coronal dentin at 200μm from



Group I 42.2 +4.4 39.1 + 3.4 40.4 + 4.3 F = 1.51

P > 0.05

Group II

NS

52.0 + 3.5 57.3 + 4.9 F = 3.77

P < 0.05S 54.5 + 4.2 S

52.7 + 2.8 51.9 + 3.9 52.6 + 2.6 F = 0.14

P > 0.05 Group III NS

F = 27.7 F = 42.9 F = 47.0 ANOVA

P < 0.01 P < 0.01 S S P < 0.01 S

30

Results

Graph II : Vicker’s Microhardness (VHN) of coronal dentin at 200μm from


42.2

54.5

52.7

39.1

52 51.9

40.4

57.3

52.6

0

10

20

30

40

50

60

Mea

n M

icro

hard

ness

Val

ue (V

HN

)



31

Results

Table III: Vicker’s Microhardness (VHN) of coronal dentin at 300μm from



Group I 42.6 + 3.6 40.0 + 1.8 39.3 + 3.7 F = 2.97

P > 0.05 NS

Group II 48.4 + 4.8 46.3 + 5.2 57.2 + 2.1 F = 18.3

P < 0.01 S

Group III 55.2 + 48 53.5 + 4.8 50.3 + 4.9 F = 2.69

P > 0.05 NS

F = 20.3 F = 25.9 F = 57.0 ANOVA

P < 0.01 S P < 0.01 S P < 0.01 S

32

Results

Graph III: Vicker’s Microhardness (VHN) of coronal dentin at 300μm from


42.6

48.4

55.2

40

46.3

53.5

39.3

57.2

50.3

0

10

20

30

40

50

60

Mea

n M

icro

hard

ness

Val

ue (V

HN

)



33

Discussion

34

Discussion

DISCUSSION

Microhardness is one of the most important physical characteristic for

comparative study of dental materials. 3 The importance of microhardness test lies in

the fact that it throws a light on the mechanical properties of a material. 34 Hardness

of dentin depends on state of mineralisation & location. Hydroxyapatite arranged in

crystal lattice affords the hardness of the healthy tissue. Sound circumpulpal dentin

has got more hardness as compared to dentin adjacent to DEJ. 2

It is possible to evaluate microhardness when there is loss of mineral due to

dissolution of inorganic part as happens during carious process and quantity gain in

density through the process of ion incorporation (Remineralisation). 35.

Hardness has been associated with relative infectivity of carious dentin

helping dentist to distinguish between infected (soft) or minimally affected (hard)

dentin. Changing orientation and density of the tubules from DEJ to the pulpal

interface may play an important part in the differences in hardness found between

these areas in healthy dentin. 2

In several studies teeth used for hardness measurement were fixed or stored in

a formalin solution, physiologic saline solution, deionised water, phosphate buffer

saline or distilled water, as there was no dehydration of the specimens after

sectioning. 19

The microhardness was checked at 10th, 20th and 30th day because after placing

glass ionomer based restoration, there will be a high rate of fluoride release for a

period of 6-12 weeks.36 And fluoride promotes remineralization and inhibits

34

Discussion

demineralization of dental hard tissue. Glass ionomer based restraction are well

known for fluoride release. 33.

The microhardness was checked at 100 μm, 200 μm and 300 μm from the

cavity floor. The reason behind this is, there will be ion exchange between restoration

and tooth structure and remineralisation of adjacent tooth structure 36.

The influence of fluoride is found in a zone of resistence to demineralization

which is atleast 3 mm thick around G.I.C. This favourable result has been attributed

to the release of fluoride from the cement and its movement into adjacent tooth

structure. The ionic radius of fluoride ion (1.36A0) is similar to that of hydroxyl ion

(1.40A0) and this has important consequences because the fluoride ion can replace the

hydroxyl ion in the apatite lattice 37.

Vickers and Knoop hardness tests seem to be preferred choice of test among

majority of the investigators 19,38.

Vickers microhardness testing (VHN) was done with Digital microhardness

tester (Zwick/Roell). Load of 25 grams was applied through the indentor with a dwell

time of 15 seconds. 38

Conventional G.I.Cs were introduced to dental profession by Wilson and Kent

(1972), RMGI was introduced in 1988 3 and compomers in 1990’s 39.

GIC’s are glass - polyalkenoate cements. They are a true acid base material,

where the base is a fluoroaluminosilicate glass with high fluoride content, and this

interacts with poly (alkenoic acid). Following mixing of the two components,

calcium polyacrylate chains form quite rapidly and develop the initial matrix that

holds the particles together. Same way aluminium polyacrylate chains forms which

35

Discussion

are less soluble and stronger. At the same time some of the fluoride is released from

the glass in the form of micro droplets that lie free within the matrix. More fluoride is

retained in the matrix, bonded to aluminium and most of the subsequent fluoride

release is the result of ion-exchange reactions. Glass ionomer in any form, can be

regarded as a fluoride reservoir. Fluoride represents approximately 20% of the final

glass powder, following mixing, the fluoride becomes available from matrix more

readily than from the original glass particles.36 Fluoride promotes remineralisation and

inhibits demineralization of dental hard tissue. 33

Conventional GIC’s presents several important properties expected from ideal

restorative materials such as fluoride release; coefficient of thermal expansion and

Modolus of Elasticity similar to that of dentin, bonding to both Enamel and Dentine.40

low solubility, high opacity, anticariogenic, retention at cervical area (75%) as

compared to composite. 41

Fluoride release detected through various methods like: Spectrophotometry or

fluorometry, fluoride ion specific electrode, Gas chromatography, Aluminium

mono fluoride molecular absorption spectrometry (Al F MAS), Secondary ion mass

spectrometry (SIMS), Proton - induced x-ray emission (PIXE), Proton – induced

gamma – ray emission (PIGE), Electron probe microanalysis (EPM), and x-ray

induced photoelectron spectroscopy (XPS also called ESCA).42

Fluoride and other ions have been detected in high concentration in dentin

adjacent to GIC restorations and by placing G.I.C onto demineralised dentin, it

resulted in hypermineralisation of the dentin. 5

36

Discussion

The main disadvantages of conventional GIC are: Suscepetibility to

dehydration,43 less setting time, less esthetic, technique sensitivity 23 and reduced

occlusal wear resistance. 44

The reason for using RMGI in this study, because of caries inhibition and

fluoride release similar to conventional GIC, 33 better esthetics, adhere to tooth

structure and possess the capacity to inhibit both in vivo and in vitro secondary caries,

16 less sensitive to water dehydration and dissolution because of rapid setting; better

rechargeablity, 23 finished at time of placement, stronger than traditional G.I, light

cured to depth of 2.7 mm,7

RMGI powder components consist of ion-leachable fluoroalminosilicate

glass-particles and initiators for light curing and or chemical curing. The liquid

component usually contain water and polyacrylic acid or polyacrylic acid modified

with methacrylate and hydroxyethyl methacrylate (HEMA) monomers. The initial

setting reaction of the material occurs by polymerization of methacrylate groups. The

slow acid base reaction will ultimately be responsible for the unique maturing process

and the final strength.1

The reason for using compomer in this study is because of structure and

physical properties similar to those of composite, fluoride release, bond strength to

tooth structure similar to conventional GIC, light cured upto 4.7mm, 7 better

compressive strength and flexural strength, 18 when used in class V restoration

provide better marginal adaptation to dentin than composite. 27

Compomer is usually provided as a one paste system. It consist of silicate

glass particles, sodium fluoride and polyacid modified monomer without any water.

Setting is initiated by photo polymeristion of the acidic monomer that yields a rigid

37

Discussion

metarial. Acid base reaction is induced by water absorption through saliva, that

eventually sustains fluoride release. 1

RMGI and compomer claim to improve the mechanical properties while

retaining esthetic, adhesion and fluoride release. 6




Group I : “ Class V Cavities without Restorations” (Control):

This group showed no significant changes in Vickers microhardness (VHN)

upto 30th day and at 100,200,300 μm from cavity floor. Caries results in

demineralization of inorganic substance followed by dissolution organic substance

resulting in loss of tooth structure. There will be loss of mineral content from the

demineralised dentine 7 studies have been reported that in both deciduous and

permanent dentin, the hardness of the peripheral dentin was lower than that of central

dentin, and the hardness of the pulpal dentin was lowest. Lower hardness values, 100

to 200 μm from DEJ were also reported, probably due to the presence of mantle

dentin. Hardness values of dentin decrease with distance from DEJ. Central area of

coronal dentin is harder than peripheral dentin.19

Group II: Class –V cavities restored with RMGI:

The results showed that, an increase in Vicker’s microhardness (VHN) by the

end of 30th day. Reason for this:

38

Discussion

Remineralisation, has received considerable attention during the past decades

and has become one of the cornerstones of the fluoride treatment strategy. The

phenomenon of remineralisation was first described by Head in 1909.45 Fluoride

promotes remineralization and inhibits demineralization of adjacent tooth structure. 33

Enzyme alkaline phosphatase present in dentine increases the concentration of

phosphates and these combine with calcium taken up from tissue fluid to form

calcium hydroxyapatite.46 The lost calcium from calcium hydroxyapatite is replaced

by fluoride which results in formation of fluorohydroxyapatite which is less soluble as

compared to hydroxyapatite.45 Fluoride, Strontium and Calcium released from glass

ionomer based restoration helps in remineralization of adjacent tooth structure 5,14,17,45

There is an constant increase in fluoride release over a period of 6 weeks with RMGI

30 and the release is equal to or higher than conventional GIC. 6,33

Group III: Class V cavities restored with Compomer.

The results of this group showed no significant changes in Vickers

microhardness (VHN) upto 30th day and at 100,200,300 μm from cavity floor. The

microhardness values (VHN) was significantly lower than group II. The reason

behind this:

As we know fluoride helps in remineralization of adjacent tooth structure

5,14,17,33. The rate of fluoride released from compomer decreases over time.33 Fluoride

release from compomer is less as compared to RMGI and GIC.6,18,23 This is because

of low fluoride release, limited acid base reaction6,40 and also due to presence of

lesser amount of glass ionomer. 41

39

Discussion

Group II vs Group III:-

When Vicker’s microhardness (VHN) was compared between group II and

Group III. Group II i.e., class – V cavities restored with RMGI showed more hardness

values. The reason for this: As we know, fluoride promotes remineralisation and

inhibits demineralization of dental hard tissue.33 The lost calcium from calcium

hydroxyapatite, is replaced by fluoride resulting in formation of flruorohydroxyapatite

which is less soluble as compared to hydroxyapatite.45 Other than fluoride, calcium

and strontium released from glass ionomer based restoration results in

hypermineralisation of adjacent tooth structure 5,14,17,45 The fluoride released from

RMGI is high or equal to that of conventional G.I.C. 6,33

The fluoride release from compomer is less as compared to RMGI 6,23,33,40. As

the rate of fluoride release from compomer decreases over time, the remineralisation

affect also decreases with time.33 The chemistry behind the decrease in fluoride

release with compomer is because of limited extent of the acid base reaction. 40

Because of the lower amount of glass ionomer present in compomer, the amount of

fluoride release are lower than that of glass ionomer & RMGI. 41

There was decrease in microhardness at 300 µm at 10th , 20th and 30th day for

group II and group III, this is because, there is ion exchange between restoration and

tooth structure and remineralization of adjacent tooth structure. The influence of

fluoride is found in a zone of resistence to demineralization which is atleast 3mm

thick around GIC. This favourable result has been attributed to the release of fluoride

from the cement & its movement into adjacent tooth structure. 36 ,37

40

Discussion

Limitations of the Study

1) There is a question about the long term action of these materials (RMGI and

compomer), because microhardness measurements were taken for 1 month

period of study.

2) It is known that glass ionomer cements can function as a fluoride reservoir and

can reaptake fluoride from the oral environment again, thus recovering its

anticariogenic action with time.

3) Drawbacks of using Vicker’s microhardness

a) Measures the hardness after indentation is removed.

b) Resolution variations of optical system

c) Perception of operator

d) Elastic recovery of material after the load is removed.

4) The present study was done invitro, therefore not truly mimicking the true oral

environment.

Recent advances are available at present for checking the microhardness like

Martens hardness test. It is also possible to quantify the mineral content present in

dentin. The further research is carried out to check the microhardness variation with

other resent biomaterials.

41

Conclusion

42

Conclusion

CONCLUSION

On the basis of the study carried out, the results obtained using RMGI and

compomer in class-V cavities and their effect on microhardness of dentin, shows that:

Resin modified glass ionomer (RMGI) showed increase in microhardness of

dentin as compared to compomer and control group (class-V without restoration).

So this shows the use of biomaterials with improved mechanical properties

like flexural strength and fluoride release enhances the structure and microhardness of

dentin.

42

Summary

7142

Summary

SUMMARY

Microhardness is one of the most important characteristic for comparative

study of dental biomaterials. As we know fluoride promotes remineralisation of dental

hard tissue and inhibits demineralization. GIC are well known fluoride releasing

restorative material. But conventional GIC are susceptible to dehydration, less

setting time, less esthetic and reduced occlusal wear resistance.

The present study was yet another effort to solve this whelming problem and

in this study, we have used improved quality of glass ionomer based restoration.

The aim of the present study was an invitro comparative evaluations of

microhardness of coronal dentin with RMGI and compomer in Class V restoration.

Thirty freshly extracted human permanent molars with Class V carious

infected lesion were selected and stored in normal saline. Class V cavity preparation

for all groups were standardized with occluso-cervical width of 2mm, mesio-distal

width of 5mm and depth of 2mm from cavity margins. Group I (n=10) : class V

cavities without restoration (conrol), Group II (n=10) Class V cavities with RMGI

and Group III, Class V cavities with compomer.

After storing the samples in normal saline for 10 days, the samples bottled dry

and embedded in acrylic resin. Sectioning was done and then subjected to

microhardness measurements by using digital microhardness tester (Zwick / Roell) at

10th, 20th and 30th day under load of 25 grams for 15 seconds at a distance of 100 μm,

200μm and 300 μm from cavity floor.

The data was recorded and submitted to statistical analysis. The results

showed, an increase in microhardness of dentin adjacent to RMGI as compared to

compomer. And the control group showed the least valves of microhardness of dentin.

724243

Bibliography

734243

Bibliography

BIBLIOGRAPHY

1. Anusavice Phillips Science of Dental Materials 2003;11th Edition, Elsevier.

New Delhi(India).

2. A. Banerjee, M.Sheriff, A.M. Kidd and T.F. Watson A confocal Microscopic

study relating the autofluorescence of carious dentine to its microhardness.

British Dental Journal, 1999; 187(4):206-210.

3. J. Ellakuria, R. Triana, N. Minguez et al Effect of one-year water storage on

surface microhardness of resin modified versus conventional glass-ionomer

cements. Dental material, 2003;19:286-290.

4. Susana M.W. Samuel and Catia Rubinstein Microhardness of Enamel Restored

with Fluoride and non-fluoride releasing dental materials. Braz. Dental Journal :

2001; 12(1):35-38.

5. Y. Kitasako, M. Nakajima. RM Foxton, K Aoki, PNR Pereira. J Tagami..

Physiological remineralisation of artificially demeneralised dentin beneath

glass-ionomer cements with and without bacterial contamination invivo,

Operative Dentistry, 2003;28(3):274-280.

6. N Attar and MD Turgut.. Fluoride release and uptake capacities of fluoride

releasing restorative materials, Operative Dentistry, 2003;28(4):395-402.

7. Theodore M Roberson. HO Heymann. EJ Swift.). Sturdevant’s Art and Science

of Operative Dentisty, 2006;6th Edition Elsevier, New Delhi (India).

8. D.L. Davidson, I.S. Hoekstra and J. Arends. Microhardness of sound,

decalcified and etched tooth enamel related to the calcium content, caries

Research 1974;8: 135-144.

44

Bibliography

9. Frank Seaman and Ira L. Shannon Fluoride treatment and microhardness of

dentin, Journal of Prosthetic Dentistry, 1979; 141(5): 528-530.

10. Pashley D, Ukabe A and Parham P.. The relationship between dentin

microhardness and tubule density. Endod Dental Traumatol, 1985;1:176-179.

11. F.M. Herkstroter, M. Witjes, J. Ruben and J. Arends. Time dependency of

microhardness indentations in human and bovine dentine compared with human

enamel, Caries Research, 1989; 23:342-344.

12. Monica Campos Serra and Jaime A.C. The invito effect of glass-ionomer

cement restoration on enamel subjected to a demineralization and

remineralisation model, Quintessence International, 1992;23(2):143-147.

13. S.B. Geiger and S. Weiner.. Fluoridated carbonatoapatite in the intermediate

layer between glass-ionomer and dentin, Detal Materials, 1993;9:33-36.

14. J.M. Ten Cate and R.N.B. van Duinen. Hypermineralization of Dentinal lesions

adjacent to glass-ionomer cement restorations, Journal of Dental Research,

1995;74(6):1266-1271.

15. C.M. Kreulen, J.J.de Soet, K.L. Weeheijm and W.E. van Amerongen. In vivo

cariostatic effect of resin modified glass ionomer cement and amalgam on

dentine, Caries Research, 1997;31:384-389.

16. P.N.R. Pereira, S. Inokoshi, T. Yamada and J. Tagami. Microhardness of in vitro

caries inhibition zone adjacent to conventional and resin-modified glass-

ionomer cements, Dental Materials, 1998; 14:179-185.

45

Bibliography

17. H. Ngo. V Marino and G.J. Mount. Calcium, Stronium, Aluminium, Sodium and

Fluoride release from four glass ionomer cements, Journal of Dental Research,

1998;77 (Abstracts), p. 41.

18. IHEL-Kalla and F. Garcia-Goddy. Mechanical properties of compomer

restorative materials, Operative Dentisty, .1999;24: 2-8.

19. Y Hosoya, SJ Marshall, LG Watanabe and GW Marshall. Microhardness of

carious deciduous dentin, Operative Dentisty, 2000;25:81-89.

20. WW Brackett, WD Browning, JA Ross and MG Brackett. Two year clinical

performance of a polyacid-modified resin composit and a resin-modified glass-

ionomer restorative material, Operative Dentistry, 2001;26:12-16.

21. Carvalho RM, Fernandes CAO, Villanueva R, Wang L and Pashley DH..

Tensile strength of human dentin as a function of tubule orientation and density.

Journal of Adhesive Dentistry, (2001)3,4,309-314.

22. Freitas PMD, Basting RT, Rodrigues AL, Serra MCEffect of two 10% peroxide

caramicle bleaching agents on dentin microhardness at different time intervals,

quintessence International, 2002; 33(5):370-375.

23. R. Freedman and KE Diefenderfer.). Effects of daily fluoride exposures an

fluoride release by glass-ionomer based restoratives, Operative Destistry,

2003;28(2):178-185.

24. Vicoria Fuentes, Manuel Toledano, Raquel Osorio and Ricardo M. Carvalho.

Microhardness of superficial and deep sound human dentin. Journal of

Biomedical Materials Research, 2003;66A:850-853.

46

Bibliography

25. J. Pak. Dent Assoc. Microhardness and meral contents of sound and carious

human primary teeth. 2004; www.Pak Medi Net.

26. A. Vieira, R.Hancock, M. Dumitriu, M. Schwartz, H. Limeback and M.

Grynpas. How does fluoride affect dentin microhardness and mineralization?

Journal of Dental Research, 2004; 84(10):951-957.

27. Qingshan Li, Soren Jespen, Hans-arl Albers and Jorg Eberhard. Fluoride

materials as an intermediate layer could improve the marginal and internal

adaptation of composite restorations in Class V Cavities. Dental Materials,

2006; 22: 250-257.

28. M.J. Altenburger, J.F. Schirrmeister, K.T. Wobas and E.Hellwig.

Remineralisation of artificial interproximal carious lesions using a fluoride

mouthrinse. American Journal of Dentistry. 2007;20(6):385-389.

29. A. Wiegand, W.Buchalla and Thomas Attin. Review on fluoride-releasing

restorative materials. Fluoride release and update characteristics, antibacterial

activity and influence on caries formation. Dental Platerials, 2007; 23:343-362.

30. Deniz C. Can-Karabulut, Inci.B, Hikmet Sand Mustafa. T. Linear regression

modeling to compare fluoride release profile of various restorative materials

Dental Materials, 2007;23:1057-106.

31. A. Menters and E.A. Haznedaroglu. In vitro hardness of enamel after two

different G.I.C fissure sealant materials. Caries Research, 2007; 41

(Abstracts):p 271.

47

http://www.pak/

Bibliography

32. T. Thuy, H. Nakagaki, P.A.Hung, J. Inukai, S. Tesuboi and C.RobinsonEffect of

fluoride combined with strontium on enamel remineralisation in vitro. Caries

Research, . 2007;41 (Abstracts): p 329.

33. H.S.Lee, J.H. Berg, Franklin G.G and ki-Taeg Jang. Long-term evaluation of the

remineralization of interoproximal caries-like lesions adjacent to glass-ionomer

restorations: A micro. CT study American Journal of Dentistry; 2008l;

21(2):129-132.

34. EC Say, A Civelek, A Nobecourt et al. Wear and Microhardness of different

Resin Composite Materials. Operative Dentistry, 2003;25(5);628-634.

35. B.M. Santiago, D.A Ventin, L.G. Primo and R. Barcelos “Microhardness of

dentine underlying ART restorations in primary molars: an in vivo pilot study.

British Dental Journal 2005;199(2):103-106.

36. Grahm J. Mount An Atlas of Glass-ionomer cement; A clinician’s guide. 2002;

Martin Dunitz, London.

37. Alan D. Wilson and John. W.Mc Lean Glass-ionomer Cement, 1998;

Quintessence Books, Chicago.

38. Shakeel A.S, John F. Mc Cabe, steven Bull…, et al Hardness measured with

traditional Vickers and Martens hardness methods. Dental Materials, 2007;

23,1079-1085.

39. John W. Nicholson. Play-acid modified composite resins (Compomer’s) and

their use in clinical dentisty. Dental materials, 2007; 23:615-622.

48

Bibliography

40. M.A. Cattani Lorente, V.Dupuis, F.Moya.., et al Comparative study of the

physical properties of a palyacid-modified composite resin and a resin-modified

glass-ionomer cement. Dental Material, 1999; 15:21-32.

41. Robert G. Craig and John M.Powers Restorative Dental Materials. 2002; 11th

Edition. Harcourt India.

42. Ole Fejerskov, Jan Ekstrand and Brian A .Burt. Fluoride in dentistry. 2nd

edition, 1996; Munksgaard, Copenhagen.

43. Pedro P.C. Souza, Andnexa M.F. Aranha, Josimeri Hebling.., et al. In vitro

cytotoxicity and invivo biocompatibility of contemporary resin-modified glass-

ionomer cements. Dental materials, 2006;22:838-844.

44. M.G. Gandolfi, S. Chersoni, G.L. Acquaviva…, et al. Fluoride release and

absorption at different pH from glass-ionomer cements. Dental materials, 2006;

22:41-449.

45. J.M. Ten Cate and Cor von Loveren. “Fluoride mechanics, DCNA 1999;43(4)

713-742.

46. G.S.Kumar, “Orbans Oral Histology and Embryology, 12th edition,

2008;Elsevier, New Delhi (India).

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Annexure

50

Annexure

ANNEXURE

Days Distance from

cavity floor (µ m) Groups 10th Day 20th Day 30th day

100 40.9 + 4.0 37.1 + 2.4 39.6 + 4.9

200 42.2 + 4.4 39.1 + 3.4 40.4 + 4.3 Group I

300 42.6 + 3.6 40.0 + 1.8 39.3 + 3.7

100 54.2 + 2.2 57.0 + 2.3 59.9 + 3.3

200 54.5 + 4.5 52.0 + 3.5 57.3 + 4.9 Group II

300 48.4 + 4.8 46.3 + 5.2 57.2 + 2.1

100 50.7 + 2.6 50.9 + 1.8 52.4 + 3.6

200 52.7 + 2.8 51.9 + 3.9 52.6 + 2.6 Group III

300 55.2 + 4.8 53.5 + 4.8 50.3 + 4

5150

52

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Documents

Dr. PRAKASH LOKHANDE