Download a) BRIEF RESUME OF THE INTENDED WORK NEED FOR THE

a)
BRIEF RESUME OF THE INTENDED WORK
For several years clinicians have recognized the importance of
NEED FOR THE STUDY
:
conservative approach to cavity preparation with the view to
maintain the strength of the tooth and to reduce the incidence of
fracture. Teeth weakened by cavity preparation should be
reinforced by restorative materials to strengthen the remaining
tooth structure. Dental Amalgam is an excellent, widely used
restorative material in dentistry since decades. However amalgam
does not bind the walls of the cusps together thus does not
strengthen the remaining tooth.1 It may also leads to discoloration
of the tooth over a period of time. Hence it has been necessary to
look for restorative materials which might overcome these flaws.
The newer materials such as Zirconomer (White Amalgam) and
Sonicfill claim to overcome these disadvantages of the dental
amalgam. The manufacturers of Zirconomer (White Amalgam)
claim that this material has superior bond strength, it does not
cause discoloration and it has sustained high fluoride release for
anti-cariogenic benefits especially in cases with high caries risk.
The manufacturers of Sonicfill claim that it has a superior strength
and high depth of curing. Hence this is a comparative study to
evaluate the fracture resistance of two new bonded restorations
with silver amalgam restoration.
This article reports the fracture strength of maxillary
REVIEW OF LITERATURE
:
premolars in which class II amalgam cavities were evaluated and
were restored with silver amalgam. One hundred freshly extracted
maxillary premolars divided into 10 groups of 10 teeth each
Group I: Sound, unprepared teeth, as controls. Group II: MO
preparation, one-fourth the intercuspal distance. Group III: MO
preparation, one-third the Intercuspal distance. Group IV: MO
preparation, one-half the Intercuspal distance. Group V: DO
preparation, one-fourth of the inter-cuspal distance. Group VI: DO
preparation, one-third of the inter-cuspal distance. GroupVII: DO
preparation, one-half of the inter-cuspal distance. GroupVIII:
MOD preparation, one-fourth of the inter-cuspal distance. Group
IX: MOD preparation, one-third the inter-cuspal distance.
GroupX: MOD preparation, one-half of the inter-cuspal distance.
Compressive forces were applied using Tensometer Universal
Testing Machine with the steel sphere 5.0mm in diameter. The
load required to fracture the teeth were recorded in kilograms and
subjected to statistical analysis (Analysis of Duncan’s multiple
range test). The results obtained showed that no statistical
difference existed for the strength of teeth with MOD or DO
preparations of the same width. Teeth prepared to one-fourth the
intercuspal distance were statistically superior to those with an
isthmus measuring one-third or one-half the intercuspal distance.5
In this article fracture resistance of 40 maxillary premolars in
which ideal class II mesio-occlusal or disto-occulsal cavities were
prepared and restored with silver amalgam, posterior composite
and glass cermet. GroupI-five intact teeth. Group II-five teeth with
class II cavities prepared and restored. GroupIII-ten teeth with
class II cavities prepared and restored with silver amalgam. Group
IV-ten teeth with class II cavities prepared and restored with
dentin bonded posterior composite resin and Group V-ten teeth
with class II cavities prepared and restored with glass cermet. All
the forty extracted teeth were then subjected to Universal Testing
Machine and the loads required to fracture the teeth were recorded
in kilograms and data obtained were subjected to statistical
analysis (ANOVA). It was found that the values of class 2 cavity
prepared and unrestored are the lowest and that of the teeth with
class II cavity prepared and restored with dentin bonded posterior
composite resin is highest. Teeth with class II cavities prepared
and restored with glass cermet had highest fracture resistance than
intact teeth whereas teeth with class II cavities prepared and
restored with silver amalgam had lowest values than intact teeth.2
This study compares the fracture resistance of teeth
restored with conventional amalgam with those restored with
amalgam bonded to tooth structure with a resin liner. Fourteen
pairs of teeth were prepared with mesio-occulsal-distal amalgam
type cavities. One tooth in each pair was randomly assigned to
conventional amalgam group and the other to the bonded
amalgam group. All the specimens were then subjected to
Universal Testing Machine. The forces required to fracture the
teeth were recorded and results were analysed with matched pairs
t-test. Fractured surfaces were examined by scanning electron
microscopy. The results were that teeth restored with amalgam
bonded to the tooth fractured at a greater load than teeth restored
with conventional amalgam.3
This study compared the cuspal fracture resistance
of posterior teeth restored with four different adhesive
restorations. Group I: Unprepared, intact teeth. Group II: Hybrid
composite (Filtek Z250). Group III: Packable composite (Filtek
P60). Group IV: Ormocer (Definite) Group V: Amalgam (SDI
Permite) with an amalgam bonding agent (Amalgam Bond Plus).
All the specimens were tested on Instron Universal Testing
Machine for the resistance to fracture. Teeth was preloaded to
maximum force of 10kgf speed of 5mm/min. Data was anaylsed
using one-way analysis of variance (ANOVA) and Tukey test.
The results show that 1) Fracture of restored teeth with hybrid and
packable composite often occurred at the interfacial area.
2)Fracture of restored teeth with ormocer and amalgam were
found in small number at the interfacial area compared to hybrid
and packable composite. 3)Amalgam and ormocer groups
demonstrated cohesive failure in restoration materials associated
with tooth crack.4
This study evaluated the fracture resistance of maxillary
premolars with class II disto-occulsal preparations restored with
light cured composite with beta quartz SQ inserts, light cured
composite
layered
incrementally and
silver
amalgam
in
comparison with intact and un restored teeth. Sixty extracted
maxillary premolar were randomly divided into 6 groups of 10
teeth.
Group
I:
Sound,
unprepared
teeth.
Group II: Disto-occlusal cavity prepared but unrestored. Group
III: Disto-occusal cavity prepared and restored with light cure
composite with beta quartz inserts. Group IV: Disto- occlusal
cavity prepared and restored with light cured composite
incrementally placed in horizontal layers. Group V: Disto-occlusal
cavity prepared and restored with light cured composite
incrementally placed in alternating oblique layers. Group VI:
Disto-occlusal cavity prepared and restored with high copper
silver amalgam. The specimens were tested on Universal Testing
Machine for the fracture resistance with the compressive load of
cross head speed of 0.1mm per second. The load required to
fracture the teeth were recorded in kilograms and subjected to
statistical analysis. The results showed that the mean compressive
load in Group I was significantly higher than rest of the groups (II,
III, IV, V, VI). Group III (light cured composite with beta quartz
glass ceramic inserts) were significantly higher than Group II
(disto-occulsal cavity prepared but unrestored). Group V
(obliquely placed composite resin) showed much higher values
than Group IV (composite resin placed horizontal increments).
Group IV (composite resin placed in horizontal increments) was
inferior to Group VI (amalgam restorations).1
1) To assess the fracture resistance of the teeth restored with
:
OBJECTIVE OF THIS STUDY
sonicfill and zirconomer.
2) To compare the fracture resistance of sonicfill and
zirconomer restorative materials with silver amalgam.
 MATERIALS:
b)
MATERIALS AND METHODS
1) 50 Freshly extracted, human non-carious maxillary first
premolar teeth.
2) Airotor.
3) #2 round bur.
4) #56 straight fissure bur.
5) #245 Pear-shaped bur.
6) Tofflemire Matrix band retainer.
7) Silver Amalgam.
8) Sonicfill.
9) Zirconomer.
10) Universal Testing Machine.
* (Non-availability of any material may necessitate a replacement
by another material)
50 freshly extracted, non-carious human maxillary first premolars
SOURCE OF THE DATA
extracted as part of orthodontic treatment will be collected from
Department of Oral and Maxillofacial Surgery, S.D.M COLLEGE
OF DENTAL SCIENCES & HOSPITAL, DHARWAD.
SELECTION OF THE TEETH:
METHOD OF COLLECTION OF DATA
50 freshly extracted human maxillary first premolars will be
cleaned and stored in 10% formalin solution (pH 7.0).
Inclusion criteria1) Non-carious maxillary first premolar.
Exclusion criteria1) Carious teeth.
2) Teeth with pre-existing cracks.
METHODOLOGY:
The roots of the teeth will be embedded in acrylic resin 2mm
below the cemento-enamel junction (approximately the level of
the alveolar bone in a healthy tooth), with the cusp tips aligned in
the same plane to ensure a more equal distribution of the load
during testing. Ideal Class II mesio-occlusal cavity preparation
will be done on 40 teeth. The preparation will be standardized and
done under water spray in a high speed handpiece. Finishing will
be done with the suitable hand instruments.
The teeth will be then randomly divided into five groups. One
group with intact teeth will serve as the control group and the
remaining teeth are divided in the following manner.
GROUPS:
n=10
GROUP I
Unprepared intact teeth
(Positive Control
Group)
GROUP II
Teeth
(Negative Control cavity
with
prepared
Group)
unrestored.
GROUP III
Teeth
cavity
class
with
and
class
prepared
restored
II
with
II
and
silver
amalgam.
GROUP IV
Teeth
cavity
with
class
prepared
II
and
restored with Sonicfill.
GROUP V
Teeth
cavity
with
class
prepared
restored
Zirconomer.
II
and
with
The prepared samples will be then subjected to fracture using
Universal Testing Machine. The load required to fracture the teeth
will be recorded in kilogram.
STATISTICAL ANALYSIS:
Data obtained will be subjected to
statistical analysis.
DOES THE STUDY REQUIRE ANY INVESTIGATION
OR
INTERVENTION
TO
BE
CONDUCTED
NO
ON
PATIENTS OR ANIMALS
HAS ETHICAL CLEARANCE BEEN OBTAINED
YES.
FROM YOUR INSTITUTION
1) Solomon P, Krishna G, Parmeswaran A, Pradeep G,
c)
LIST OF REFERENCES
Kandaswamy D.
Fracture resistance of premolars teeth with
class II preparations restored with light cured composite with beta
quartz inserts, light cured composite and silver amalgam in
comparison with intact unrestored teeth - An in-vitro study. J
Conserv Dent 2007;10:122-128.
2) Jagadish S, Yogesh B G. Fracture resistance of teeth with
class 2 silver amalgam, posterior composite and glass cermet
restorations. Oper Dent 1990;15:42-47.
3) Eakle WS, Staninec M, Lacy AM. Effect of bonded amalgam
on the fracture resistance of teeth J Prosthet Dent 1992;68:257260.
4) Gorucu J, Ozgunaltay G. Fracture resistance of teeth with
class II bonded amalgam and new tooth-coloured restorations.
Oper Dent 2003;28:501-507.
5) El-Sherif MH, Halhoul MN, Kamar AA, El-Din AN.
Fracture strength of premolars with class 2 silver amalgam
restorations. Oper Dent 1988;13:50-53.