PubMed · 10036837
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S Carstensen. 1999. Orthodontic separators.. https://doi.org/10.14219/jada.archive.1999.0148
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STATEMENT OF PROBLEM: Provisional crowns traditionally have been associated with problems such as poor occlusion, contour, fit, and finish. Fabrication procedures should be uncomplicated and predictable within a realistic time frame. PURPOSE: The purpose of this study was to compare the quality of provisional restorations fabricated by dental students from 2 different materials (bis-acryl composite resin and PMMA) and identify the advantages and disadvantages associated with each material. MATERIAL AND METHODS: This study evaluated the occlusion, contour, marginal adaptation, and finish of 222 provisional crowns fabricated by 2 groups (A and B) of dental students. One bis-acryl composite resin material (Integrity) and 2 PMMA resins (C&B Resin and Snap) were evaluated. RESULTS: For group A, Integrity was statistically superior (P<.05) to C&B Resin in all 4 categories for anterior provisional crowns. For posterior provisional crowns, Integrity proved superior in the categories of contour and marginal adaptation, but no significant differences were established for occlusion and finish. For group B, Integrity was statistically superior to Snap in the categories of occlusion, contour, and marginal adaptation, whereas there was no statistical difference in finish. When all 4 categories were analyzed, Integrity was found to be statistically superior. CONCLUSION: Bis-acryl composite resin (Integrity) was significantly superior to PMMA (C&B Resin and Snap) as a provisional restorative material.
STATEMENT OF PROBLEM: When inexperienced clinicians perform class II composite restorations, improper placement techniques can lead to problems, including marginal adaptation and void formation. PURPOSE: The aim of this study was to determine the influence of flowable composite linings on marginal microleakage and internal voids in class II composite restorations performed by practitioners with different levels of experience. MATERIAL AND METHODS: Eighty extracted molars were prepared with mesial and distal class II cavity preparations and divided into 4 groups. Each group was restored separately with the following materials: Prodigy/Revolution lining (group I), Prodigy (group II), Tetric Ceram/Tetric Flow lining (group III), and Tetric Ceram (group IV). Each group was equally divided and restored by 2 practitioners, one experienced and another untrained in composite restorations. After restoration, all teeth were stored for 24 hours, thermocycled (at 5 degrees C to 60 degrees C) 1500 times, and soaked in 2% basic Fuchsin dye for 24 hours. After soaking, the teeth were sectioned, and gingival marginal microleakage and internal voids (at the gingival wall interface and in the cervical and the occlusal parts) were recorded. Data were analyzed with the Kruskal-Wallis test. RESULTS: There was no significant reduction in microleakage for either practitioner. There were fewer interface voids within pairs with or without flowable composite linings made by the experienced practitioner (P<.05). CONCLUSION: When flowable composite lining was placed at the gingival floor of a class II composite restoration by an experienced practitioner, voids in the restored interface were reduced. Gingival marginal sealing was not improved by the same technique.
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