SYNOPSIS

Dr.SMITHA GUJJAR

POST GRADUATE STUDENT

DEPARTMENT OF PROSTHODONTICS

K.V.G.DENTAL COLLEGE & HOSPITAL,

KURUNJIBAG-SULLIA (DK)

KARNATAKA, INDIA

Rajiv Gandhi University of Health Sciences, Karnataka

Bangalore

ANNEXURE-II:PROFORMA FOR REGISTRATION OF SUBJECTS FOR DISSERTATION

1. / NAME OF THE CANDIDATE AND ADDRESS (IN BLOCK LETTERS) / Dr.SMITHA GUJJAR B
POST GRADUATE STUDENT,
DEPARTMENT OF PROSTHODONTICS
K.V.G.DENTAL COLLEGE & HOSPITAL,
KURUNJIBAG-SULLIA(DK)
KARNATAKA,INDIA-574 327
2. / NAME OF THE INSTITUTION / K.V.G.DENTAL COLLEGE & HOSPITAL,
KURUNJIBAG-SULLIA(DK)
KARNATAKA,INDIA-574 327
3. / COURSE OF STUDY AND SUBJECT / MASTER OF DENTAL SURGERY
PROSTHODONTICS INCLUDING CROWN & BRIDGE
4. / DATE OF ADMISSION OF COURSE / 25TH MAY ,2010
5. / TITLE OF THE TOPIC: / AN IN-VITRO STUDY COMPARING THE ACCURACY OF POLYETHER, ADDITION SILICONE AND NEWLY FORMULATED VINYL SILOXANE ETHER ELASTOMERIC IMPRESSION MATERIAL.
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8. / BRIEF RESUME OF THE INTENDED WORK
6.1 NEED FOR THE STUDY :
Impression of the teeth and the surrounding structures is of utmost importance, as it is neither possible nor desirable to make patterns for fixed prosthesis directly in the mouth.1
Dimensional accuracy when making impression is crucial to the quality of fixed prosthodontic treatment and the impression technique is a critical factor affecting this accuracy.2 The problem of the accuracy of impressions has been stressed recently in a clinical study, which reported that over 89% of impression investigated had one or more observable errors; thus, a more critical evaluation of the impression on the part of the dentist is recommended. Several factors can influence the quality of impressions, including the impression technique, the impression material, the bulk of material, and others.2 Despite a number of studies on the accuracy of impression as related to impression material and impression technique controversies do remain.2
Accuracy of the impression material in terms of both dimensional accuracy and detail reproduction is an essential prerequisite for a successful impression.3
After world war II advances in polymer technology brought to the dental profession a group of synthetic rubbery materials called elastomers which were capable of making the impressions of both soft and hard tissues4.Initially this group consisted exclusively of polysulfide impression materials. Subsequently condensation cured silicones were developed. Today the most popularly used in dental practice are polyethers and additional silicones/vinyl polysiloxanes4.
Recently a new impression material classified as Vinyl Siloxane Ether by the manufacturer has been made commercially available.This material has been purported by the manufacturer to possess good mechanical and flow properties along with excellent wetting characteristics in the unset conditions when applied to the prepared tooth and also in the set conditions5. The accuracy of the new vinyl siloxane ether has not been established and is needed given the new and novel formulation 5.
The aim of this in vitro study is to compare dimensional accuracy of resultant models made of improved stone using polyvinyl siloxane, poly ether and vinyl siloxane ether impression material.
6.2 REVIEW OF LITERATURE
A study compared the accuracy of one-step putty wash with two-step putty wash impression techniques. Five addition silicone impression materials mirror 3, mirror 3 extrude, express, permagum and absolute; and a stainless steel model containing two full-crown abutment preparations were used.
It was found that accuracy of addition silicone impression material is affected more by material than technique. Accuracy of the putty wash one-step impression technique was not different from the putty wash two-step impression technique except at one of the six dimensions where one-step was more accurate than two-step. Mirror 3 putty wash two-step impression presented less distortion than mirror 3 extrude putty wash one-step or two-step impression6.
A study was done to assess the accuracy of three putty wash impression techniques using the same impression material in a laboratory model. The three techniques used were 1 step putty wash impression materials used simultaneously, 2step with 2mm relief and 2 step technique with polyethylene spacer.Results showed statistically significant difference among the three techniques for all intraabutment and interabutment measurements. It was concluded that the poly vinyl siloxane 2 step, 2mm, relief putty wash impression technique was the most accurate for fabricating stone dies. 7
In a study contemporary impression materials and techniques have been described. Impression materials vary considerably in properties like accuracy, elastic recovery, dimensional stability, flow, flexibility, workability, hydrophilicity, a long shelf life, patient comfort and economic. These differences provide a basis for the selection of specific materials in specific clinical conditions. Polyvinyl impression materials, its advantage and its interactions with latex gloves have been highlightened.1
In another in vitro study, it was shown that vinyl siloxane ether monophase impressions and vinyl siloxane ether dual-viscosity impressions display acceptable accuracy for clinical use, since the results for vinyl siloxane ether were comparable to the results for representative polyether and vinyl polysiloxane materials.5
6.3 OBJECTIVES OF THE STUDY
  1. To evaluate the intra and inter abutment dimensional accuracy of resultant improved stone models poured onto polyvinyl siloxane impressions made using one-step heavy body-light body combination technique.
  1. To evaluate the intra and inter abutment dimensional accuracy of resultant improved stone models poured onto polyether impressions made using one step medium bodytechnique.
  1. To evaluate the intra and inter abutment dimensional accuracy of resultant improved stone models poured onto vinyl siloxane ether impressions made usingone step heavy body light body combination & one step medium body impression technique.
  1. To compare the intra and inter abutment dimensional accuracy of resultant improved stone models poured onto polyvinyl siloxane, poly ether and vinyl siloxane ether impressions material
MATERIAL & METHODS.
7.1 Instruments and materials used during the course of the study-
Instruments:
  1. Stainless steel model of two abutments standardized according to ADA specification.
  2. Custom made perforated stainless steel trays with different spacing
  3. Rubber base mixing gun
  4. Rubber bowls and Plaster spatula
  5. Scissor and BP blade
  6. Carbide bur
Materials:
  1. Addition silicone impression material
  2. Poly ether impression material
  3. Vinyl siloxane ether impression material
  4. Type IV gypsum product.
  5. Tray adhesive.
Equipments:
  1. Travelling microscope
  2. Vacuum mixer for gypsum product.
  3. Mechanical mixer for elastomeric impression
METHODOLOGY.
Preparation of stainless steel abutment and trays
In this study a stainless steel model of two prepared abutments for complete crowns tapered on a lathe according to the ANSI/ADA specifications ( 8.015mm in height, 6.330mm diameter at apex and 8.450mm diameter at base of the abutment, with a 28.270mm distance between the centers of abutments ). The abutments will be incorporated with reference grooves on the occlusal surfaces for measurement2 . Custom made trays will be fabricated, which will have 6mm uniform spacing.
16 impressions from each impression system will be made (total 64). all impression will be stored at room temperature (25oc) for two hours before pouring with type IV gypsum product, will be mixed according to manufacturer’s instructions. improved stone will be first mixed by hand to incorporate the water for 10 seconds and then mixed mechanically under vacuum for 30 seconds. All the mixes will be vibrated into the impression and allowed to set for 1 hour before being separated from the impressions.
Method of collection of data:
Three different dimensions will be measured on the stainless steel model (control) and on the stone models obtained from each of the impression technique; the diameter of each abutment at base and apex, the height of each abutment, and the distance between the centre of abutments determined by cross grooves. All of these measurements will be made by travelling microscope.
STASTICAL ANALYSIS
The study will be analyzed through:-
1One-way ANOVA test
2Student Newman-Keul’s test
7.3 Does the study require any investigations or interventions to be conducted on patients or other humans or animals?
No
7.4 Has the ethical clearance been obtained from your institution in case of 7.3?
Yes
LIST OF REFERENCES
  1. Terry E. Donovan , Winston W. L.Chee. A review of contemporary impression materials and techniques. Dent Clin N Am 2004 (48): 445-70.
  2. Sergio caputi, Giuseppe varvasa:- dimensional accuracy of resultant casts made by a monophase, one step and two step, and a noval two step putty/light body impression technique, An in vitro study.JProsthet Dent 2008;99:274-81.
  3. Cynthia S., Mary P., Aisling M. -Dimensional accuracy and surface detail reproduction of two hydrophilic vinyl polysiloxane impression materials tested under dry, moist, and wet conditions. J Prosthet Dent 2003;90:365-72.
  4. Wadhwani CP, Johnson GH, Lepe X, RaigrodskiAJ. Accuracy of newly formulatedfast-setting elastomeric impression materials.JProsthet Dent 2005;93:530-9.
  5. Thomas Stober, Glen H. Johnson, Marc Schmitter- Accuracy of the newly formulated vinyl siloxanether elastomeric impressionmaterial. J Prosthet Dent 2010;103:228-239
  6. Shirley H. Hung, John H. Purk, Daniel. E. Tira, and J. David. Eick, Accuracy of one-step versus two step putty wash addition silicone impression technique. J prosthet Dent 1992;67:583-9
  7. Joseph Nissan, Ben-zionLaufer, tamarbrosh, David Assif:- Accuracy of three polyvinyl siloxane putty wash impression technique.J prosthet Dent 2000;83:161-5

Signature of the candidate
Remarks of the guide
Name and designation( in block letters) of
11.1 Guide / PROF(DR.) PRANAV MODY
11.2 Signature
11.3 Co-Guide
11.4 Signature
11.5 Head of the department / PROF(DR) PRANAV MODY
PROFESSOR AND HEAD OF THE DEPARTMENT
11.6 Signature
12.1 Remarks of the chairman and principal
12.2 Signature / PROF(DR) MOKSHA NAYAK