The Microleakage of Composite and Compomer Restorations Following Cavity Preparation With an Erbium-YAG Laser

Roebuck, Elizabeth M (1998) The Microleakage of Composite and Compomer Restorations Following Cavity Preparation With an Erbium-YAG Laser. MSc(R) thesis, University of Glasgow.

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Over the last thirty years there has been a marked decline in the caries experience in children in the United Kingdom. However, the results of recent epidemiological studies have shown that this trend has slowed down considerably, and may even have reversed in some age groups. Furthermore, there is an increasing cohort of children with significant levels of untreated dentinal decay. Anxiety is a major barrier to the uptake of dental care in the United Kingdom, the two most common stressors being cited as the dental drill and the local anaesthetic needle. The use of the hard tissue laser has been proposed as one operative mode of cavity preparation that obviates the use of both of these anxiety-precipitating stimuli. This in vitro study investigated the affect of one such instrument, the Erbium-YAG laser, on the microleakage of standardised Class V cavities at the amelodentinal junction in extracted human premolar teeth. Extracted premolar teeth were selected and randomly divided into three groups (A, B and C). Each tooth hosted one test cavity prepared with one of three laser energies (200 mJ, 240 mJ or 300 mJ with a 100 mJ finish), and one control cavity, prepared with a conventional diamond bur in a high-speed handpiece. The cavities were restored with either a composite resin or a compomer material; groups A and B were restored with a fourth generation bonding agent, Scotchbond Multi-Purpose and Z100 composite resin and were stored in 0.12% thymol solution for 24 hours and three months respectively. Cavities in group C were restored using a fifth generation bonding agent, Compoglass Single Component Adhesive and a polyacid-modified resin, Compoglass and were then stored for three months. Following storage and thermal stressing (eight hours), microleakage was assessed using a dye penetration technique and single section numerical scoring system. The data was then analysed using the Kruskal-Wallis and Mann- Whitney U tests. For the pulse energies used, it was found that the Er:YAG laser varied in its effect on both the enamel and dentine margins when compared to conventional preparation. At the enamel margin, preparation with either of the three pulse energies compared favourably to the use of the diamond bur for both materials. However, optimum cavity sealing was achieved with energies of at least 240 mJ. In comparison, dentine leakage following laser preparation was comparable to that found with conventional preparation for all laser parameters when Compoglass was used. However, there were statistical differences in leakage at the dentine margins of Z100 restorations. Lower energies of 200 mJ or higher with a low finish such as the 300 mJ with 100 mJ finish used in this study provided better long-term marginal adaptation in dentine for this material. Of these two laser energy subgroups, the 300 mJ with 100 mJ finish compared favourably with conventional cavity preparation. It was therefore concluded that, within the constraints of this study, cavity preparation with the Er:YAG laser did not have a deleterious effect on the microleakage of Class V restoration when compared to conventional preparation, providing care was taken with the choice of laser parameters for dentine and enamel for the restorative material used.

Item Type: Thesis (MSc(R))
Qualification Level: Masters
Additional Information: Adviser: W P Saunders
Keywords: Medicine, Dentistry
Date of Award: 1998
Depositing User: Enlighten Team
Unique ID: glathesis:1998-75400
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 19 Nov 2019 20:16
Last Modified: 19 Nov 2019 20:16

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