A patient in his early 20s with teeth badly discoloured by tetracycline was seeking treatment to improve his esthetics. Because retreatment and cost were important considerations, porcelain veneers were the treatment of choice. The challenge in this case was to mask the underlying tetracycline stain before the final cementation and thus gain more control over the final shade of the veneers. (+info)
Diagnostic provisional restorations in restorative dentistry: the blueprint for success.
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There is no question that patients today demand a sophisticated level of restorative dentistry, in terms of both esthetics and function. No elective restorative dentistry should be undertaken without a clear understanding of the patient's expectations and the limitations of restorative therapy. The dentist should have a clear picture in mind of the final results before initiating irreversible therapy. The use of mounted diagnostic casts, diagnostic wax-ups and provisional restorations permits patient acceptance to be obtained before the definitive phase is initiated. Too often the dentist does not take advantage of this important restorative option, with disastrous results when definitive restorations are viewed by the patient for the first time. By following the plan of treatment outlined in this article, such disasters can be avoided. (+info)
Effects of thermal cycling on dynamic viscoelastic properties of four commercial resins for crown and bridge.
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To elucidate the effects of thermal cycling on the viscoelastic properties of four commercial resins for crown and bridge, dynamic shear modulus (G'), mechanical loss tangent (tan delta), Knoop hardness, water sorption and appearance of specimen surfaces before and after thermal cycling test were determined. The changes of G' and tan delta for two materials were insignificant with increased repetitions of thermal cycling. Those of the other two materials were statistically significant: in particular, G' at temperatures above 60 degrees C was inclined to increase slightly and tan delta decreased considerably. While the Knoop hardness of the materials was a little decreased over a number of 75,000 thermal cycles, the water sorption almost attained an equilibrium in uptake after 14,000 thermal cycles. Furthermore, cracks on the specimen surface were observed after 37,500 to 75,000 thermal cycles. From these results, the deterioration of materials was observed as damage to the specimen surface. Moreover, it could be presumed that the materials would be further polymerized during the period of thermal cycling. (+info)
Unusual indelible enamel staining following fixed appliance treatment.
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Two cases are described of indelible enamel staining following fixed appliance therapy. The acquired pigmentation occurred in patients with an identifiable enamel defect prior to treatment. The interaction of factors to cause the staining is discussed and it's prevention in future cases highlighted. Subsequent restoration of the affected teeth is shown. (+info)
A resin veneer for enamel protection during orthodontic treatment.
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The aims of this study were to test the tensile bond strength of a recently developed veneer. Sound premolar teeth (120) extracted for orthodontic purposes were divided into two experimental and two control groups. In one experimental group (V1) 4-META/MMA-TBB resin (4META) was used on the surface veneer prepared with micro particle filled resin (MFR) as an adhesive for bracketing and in the second group (V2) 4META was applied on the surface veneer with the trial resin. For the controls, in group R 4META was used on the enamel surface without veneer and in group G light-cured glass ionomer cement was applied. The 30 samples in each group were divided into three groups of 10 samples and thermal cycled (TC) at 3000, 10,000 or left uncycled. Tensile testing was carried out using an Instron machine. After tensile testing the bond failures in the experimental groups were recorded using a stereomicroscope. Statistical analysis was performed using ANOVA. In group V2 the resin veneer was able to maintain sufficient bond force to enamel during clinical use. The bond strength of group V1 was significantly higher than that of groups R (P < 0.05) and G (P < 0.01) at TC 0, but for both TC 3000 and 10,000, the bond strength of group V1 was lower than groups R and G, respectively. There were significant differences between groups V1 and R (P < 0.01) for TC 3000, and between groups V1 and R and G (P < 0.01) at TC 10,000. The bond strength of group V2 was almost equal to that of group R at TC 0. At TC 3000, group V2 showed significantly lower bond strength than group R (P < 0.05), but no significant difference was found compared with group G. At TC 10,000, there were no significant differences between groups V2, R or G. When comparing groups V1 and V2, the bond strength of group V1 was significantly higher than that of group V2 (P < 0.01) at TC 0, but the bond strength of group V1 was significantly lower than that of group V2 for both TC 3000 (P < 0.05) and TC 10,000 (P < 0.01). Comparison between groups R and G, showed that the bond strength of group R was significantly higher than that of group G for both TC 0 (P < 0.01) and TC 3000 (P < 0.01), but no significant difference was found for TC 10,000. In group V2, nine samples showed adhesive failure between the veneer surface and bracket adhesive before thermal cycling. There were significant differences between the MFR and both trial resin and glass ionomer cement (P < 0.01) when examining thermal expansion. No significant difference was found between the trial resin and glass ionomer cement. It is suggested that application of a resin veneer prior to bracket bonding is suitable for clinical application to protect the teeth and to prevent decalcification and caries. (+info)
Survey of undergraduate esthetic courses in U.S. and Canadian dental schools.
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U.S. and Canadian dental schools were surveyed regarding curriculum issues related to undergraduate dental esthetic restorative courses. A one-page survey instrument was sent to deans of academic affairs (n=59) of dental schools to complete or forward to the most appropriate faculty at their respective schools who would be knowledgeable about the esthetic restorative curriculum. Responses were received from forty-two dental schools (42/59) for a response rate of 72.9 percent. The first part of the survey asked if a specific esthetic restorative course was offered at their school, if it was mandatory or elective, and details of the course length and content. The second part of the survey asked whether selected esthetic restorative procedures were included in the curriculum. Respondents to this survey indicated that most types of esthetic restorative procedures are taught whether or not an esthetic course is included in the curriculum. (+info)
Porcelain veneer bonding to enamel with plasma-arc light resin curing.
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The resin bond strength of plasma-arc curing in restorative dentistry was investigated in comparison to halogen-light curing with respect to two kinds of thickness, shade and opacity of porcelain laminate veneers. The bond strength of the light-cured resin was evaluated by shear tests and SEM observations of the fracture surfaces, and the results were interpreted in terms of the degree of resin polymerization. It was found that plasma-arc curing for 6 s was sufficient to obtain bond strengths similar to those of specimens polymerized with halogen light for 40 s, whereas the plasma-arc curing time needed to be doubled to 12 s in order to achieve similar failure patterns for a darker-shade porcelain of 2 mm thickness. The bond strength achieved by plasma-arc curing was found to be relatively unaffected by the shade or opacity of porcelain. (+info)
Crowns and other extra-coronal restorations: porcelain laminate veneers.
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Porcelain veneers are resin-bonded to the underlying tooth and provide a conservative method of improving appearance or modifying contour, without resorting to a full coverage crown. The porcelain laminate veneer is now a frequently prescribed restoration for anterior teeth. The sums spent by the Dental Practice Board on this type of treatment increased from quarter of a million pounds in 1988/89 to over seven million in 1994/95, representing some 113,582 treatments. Since that time the number has stabilised at over 100,000 veneers prescribed each year. The objective of this paper is to give a practical guide on providing these restorations. (+info)