Marginal Fit of Porcelain Veneers After Finishing Prepared Surfaces With Ultrasonic Tips

A Double-blind Split-mouth Randomized Clinical Trail Evaluating Marginal Fit of Porcelain Laminate Veneers Following Finishing the Prepared Surfaces With Ultrasonic Tips Compared to the Conventional Way

The aim of the study is to assess the marginal fit following preparation finishing with ultrasonic tips of porcelain veneers compared to the ordinary preparation using burs only. Two-hundred and forty crowns prepared to receive porcelain veneers (in a split-mouth design). On one side of the mouth, the prepared surfaces will be finished with ultrasonic tips. Marginal fit is measured by a 'cement replica technique'.

All-ceramic restoration are increasing in daily routine treatments although remain less popular than metal-ceramic crowns especially as the cost of metal rises and aesthetic requested people increases The increased demand for aesthetic treatments has led to the widespread use of metal-free ceramics for conservative restorations. Whilst studies for clinical porcelain restorations clarifies satisfactory success rates describes the reasons for failure is due to advance the techniques and materials used in dental restorations. All-ceramic restorations failures are due to several reasons, such as restoration fractures, discoloration in marginal area, marginal misfits and secondary decays. However, secondary caries is the main failure mentioned by the studies, responsible for 21% of the suddenly crown replacements. The etiology of secondary caries is as classified to primary caries, with the involvement of the same cariogenic microorganisms. The place and spread where to invade of primary and secondary lesions are also similar, with secondary caries developing mainly in the gingival tooth interface of restored teeth. Different authors have mentioned different instrumentation to prepare teeth appropriately.Preparation may be applied using diamond burs attached to sonic devices or high-speed rotating instruments with diamond or tungsten carbide burs. The action of conventional high-speed instruments applied for tooth preparation has been widely researched as well as the adhesion strengths and marginal microleakage it produces. Some authors insisted that dental surface morphology of prepared teeth is influenced by the type of bur used for preparation.

These tips are going to be used to give the final shape of the prepared surfaces before taking the impression for the construction of the veneers.

A light silicone material is going to be used to allow for measuring any gaps beneath the veneers. The measurement will be in micrometer using a microscope.

measurement will be made immediately (in the same day) of applying the constructed veneers onto the prepared dental surfaces

Inclusion Criteria: aesthetic requirement with no cracks and congenital loss of any incisors. discolored teeth not responding to bleaching. Exclusion Criteria: evidence proximal caries , edge to edge occlusion parafunctional habits root canal treated teeth.

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