Comparative evaluation of marginal adaptation and depth of cure of compomers using conventional light curing and pulse activation: An Invitro study

Jolly, Mathews (2006) Comparative evaluation of marginal adaptation and depth of cure of compomers using conventional light curing and pulse activation: An Invitro study. Masters thesis, Ragas Dental College and Hospital, Chennai.

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Abstract

INTRODUCTION : Light activated composite resin introduced in 1970 has revolutionized clinical dentistry by maximizing working time and minimizing the setting time.62 Thus the clinician has sufficient working time to sculpt the material to achieve the desired contour to mimic the morphology of the tooth structure. In the recent years the popularity of esthetic tooth colored restoration has led to a rapid increase in use of composite resins. The initially introduced dental composites were chemically cured through amine / peroxide chemistry. The limitation with the above technique has led to the development of single component resin composite activated by visible light. Visible light curing units are an integral part of modern adhesive dentistry. Visible light activated resin system use a diketone absorber to create free radical that initiate polymerization. Most dental photo initiator systems use camphoroquinone as the di-ketone absorber with the absorption maximum in the blue region of the visible light spectrum at a wave length of 450 – 490nm58. Any source of light that operates in the blue spectrum of visible light can be employed as a curing source. The aim and objective of this study is The aim of this study 1) To test the influence of pulse activation system and conventional light curing system on the marginal adaptation of polyacid modified composite resin (compomer) in class V cavity preparation. 2) To find the degree of cure and depth of cure while using two different curing modes by measuring VHN at three different heights (2mm, 3mm, 4mm) and three different loads (50g, 80,110g). The objective of the study : To recommend the best curing method that could result in adequate resin polymerization with improved mechanical properties of the set material. MATERIALS AND METHODS ; This study was done in the Department of Pedodontics and Preventive Dentistry, Ragas Dental and Hospital, Chennai and in collaboration with Central Leather Research Institute and Nuclear Physics Department (Anna University) Chennai, India. MATERIALS USED : • COMPOMER (DYRACT AP B2 SHADE) UDMA resin, TCB resin, Strontium flouorosilicate glass, Strontium fluoride, Photoinitiators, Stabilisers. • PRIME AND BOND NT (Bonding agent) Di- and trimethacrylate resin. Amorphous silica, PENTA, Photoinitiators, Stabilisers, Cetylamine hydrofluoride, Acetone. RESULTS ; The present study was carried out to evaluate the marginal adaptation of compomer and also the depth of cure of compomers using two different curing protocols- conventional (group I) and pulse activation system (group II) I. For evaluating the influence of light activation system (conventional and pulse activation) on the marginal adaptation of compomers Here group I used conventional system i.e. using constant light intensity of 400mw/cm2 for 40 sec Group II used pulse activation system i.e. using initial low intensity of 100 mw/cm2 for 4 sec followed by final cure at 400 mw/cm2 for 36 sec. Comparison was made between the groups (I and II) with heights 2mm, 3mm and 4mm. CONCLUSION : This in-vitro study was done in the Department of Pedodontics and Preventive Dentistry, Ragas Dental College and Hospital, Chennai and in collaboration with Central Leather Research Institute and Nuclear Physics department (Anna University) Chennai, India. The following conclusions were drawn from this study 1) Pulse activation group, grp II showed comparatively better marginal adaptation than conventional group, grp I. 2) There was no significant difference between the two groups for loads of 50 and 80 gm. But the top surface hardness was higher for conventional system than pulse activation system for all the groups 3) When subjected to higher loads (110 g) pulse activation group showed better hardness ratio than conventional for all heights. In other words pulse activation group could withstand or take up higher loads than conventional. Thus pulse activation can be a better choice than conventional for curing compomers (light activated resins) and could be used for restoration in stress bearing areas of cavities as well. Hence a few manufacturers’ instructions of using Dyract AP in stress bearing areas when cured with pulse activation holds good from the inference of this study. 4) The practice of curing light activated resins in increments of not more than 2mm still holds good Since this is an in-vitro study, an in-vivo study should be carried out to ascertain the longevity of restorative resins cured with different light curing protocols.

Item Type: Thesis (Masters)
Uncontrolled Keywords: marginal adaptation, depth of cure, compomers, conventional light curing, pulse activation, Invitro study.
Subjects: DENTAL > Paedodontics and Preventive Dentistry
Depositing User: Kambaraman B
Date Deposited: 19 Jan 2018 07:09
Last Modified: 19 Jan 2018 07:09
URI: http://repository-tnmgrmu.ac.in/id/eprint/5516

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