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At least 487 records · Page 27Linked to original sources

IPS Empress crown system: three-year clinical trial results.

The IPS Empress system is a highly esthetic hot pressed glass ceramic material for fabrication of single crowns. Adhesive cementation of the system not only contributes to the esthetics but is necessary for increased strength of the crown. The purpose of this prospective clinical trials was to evaluate the longevity of 75 adhesively cemented Empress full crowns. An additional aim was to assess the adhesive cementation methodology and potential side effects. At the three-year point, one molar crown fractured for a 1.3 percent failure rate. The resin cementation technique that was employed exhibited a low incidence of microleakage with few clinical side effects. There was a 5.6 percent incidence of post-cementation sensitivity, with all symptoms subsiding by eight weeks. None of the crowns in the study required endodontic therapy.

Adolescent↗

Restoring proximal integrity in posterior composite resin restorations: innovations using Ceromers.

Clinicians are increasingly being called upon to satisfy the restorative demands of patients requesting tooth coloured restorations but unable to afford an optimum indirect restorative option. Consequently, in clinical practice the envelope of what was hitherto considered the limit of appropriate application of the direct posterior composite resin technique is increasingly being stretched. Although our aesthetic endeavours are fairly easily accomplished in the posterior dentition, interproximal integrity is in many instances wanting and a major cause of restorative failure. This report highlights some of the authors innovations using Ceromers which satisfy the complex variables of clinical practice optimizing proximal contour, allowing for the successful utilization of posterior composite resin in the posterior dentition.

Ceramics↗

The skeleton buildup technique: a systematic approach to the three-dimensional control of shade and shape.

Due to the limitations of current shade-matching systems, shade communication has proven inadequate. Techniques for the fabrication of porcelain crowns that match the natural definition must address numerous factors. While all-ceramic restorations are indicated for the rehabilitation of the anterior dentition, these modalities are problematic in the restoration of teeth with discolored substrates. This article presents a systematic procedure for the three-dimensional fabrication of porcelain restorations. Techniques for building porcelain and altering the translucency of ceramic cores are also presented.

Aluminum Oxide↗

Trans-surgical restoration of extensive Class IV defects in the anterior dentition.

Direct bonding is the most commonly utilized treatment for conservative aesthetic restoration of the anterior dentition. Class IV defects require special attention due to their high incidence, particularly in young patients. One of the major challenges for the clinician in treating defects in this category is selecting the appropriate restorative composite resin material that emulates the physical and optical characteristics of dentin and enamel and conceal the fracture line at the tooth/composite interface. Class IV defects with margins violating the biologic width present another concern, since this violation often impedes the attainment of the correct anatomic contours. The learning objective of this article is to describe a technique for achieving a correct integration of the periodontium, the tooth structure, and the restorative composite resin material to achieve a high level of aesthetic excellence.

Child↗

A method of making decalcifications in the porcelain build up.

This article describes a method for making white decalcifications or modeling characterizations that attempt to duplicate natural teeth. Common techniques often use white stain applied to the wet porcelain or painted on as surface stain. A simplified and reproducible technique is provided that allows this characterization to be completed as part of the porcelain build up. A mixture of three powders causes an improved appearance that can lighten the incisal and occlusal surfaces to help create greater contrast with the body porcelain for a more natural result.

Dental Porcelain↗

Clinical evaluation of Dyract in primary molars: 3-year results.

PURPOSE: To evaluate the 3-year clinical performance of Dyract in primary molars. MATERIALS AND METHODS: In 55 children (aged 4-9 years) 91 restorations were placed and 76 were available for evaluation after 2 years. After 3 years, 40 teeth were exfoliated leaving 37 restorations for evaluation. RESULTS: During the entire study, four restorations failed and had to be replaced. One restoration fractured after 6 months and another after 1 year. Two other restorations were completely lost between the second and third year's evaluation. Furthermore, three restorations showed minimal recurrent caries, which did not need additional treatment. Wear of the restorations was considerable. However, this was also true for the point of reference for the wear measurement on the primary molars. The excellent handling characteristics and the low failure rate during the 3-year study suggest that this compomer is a reliable restorative material in primary molars.

Child↗

Anterior fixed prosthetic restorations and the bleached dentition: laboratory techniques.

The process of matching fixed prosthetic restorations to bleached dentition has often created a dilemma, as clinicians are not able to accurately communicate shade selection to the dental laboratory. By understanding the effect of vital bleaching on the dentition, it is possible to fabricate porcelain restorations that match the bleached natural teeth. This article presents a laboratory technique for utilizing a sequence of porcelain powders and stains to develop the internal anatomy (e.g., halos, mamelons, luminosity) of restorations that appear indistinguishable from the bleached dentition.

Adult↗

[Transesophageal color-coded Doppler echocardiography: diagnosis of regurgitation of mitral valve prosthesis].

In patients with mechanical mitral prosthesis, the presence of dysfunction and regurgitation of the prosthesis may be difficult to assess by standard precordial color flow Doppler. Moreover, the kind of mitral prosthesis regurgitant jet is often impossible to determine. We have recently studied 4 patients with clinically suspected mitral prosthesis dysfunction. In all of them the conventional transthoracic color flow technique was unable to evidentiate prosthesis regurgitation, whereas the transesophageal color flow Doppler assessed a partial displacement with a peri-prosthetic regurgitation in 3 patients, and a prosthetic endocarditis with intra-prosthetic regurgitation in 1. All studies were performed using an Aloka SSD 860 and 5 MHz transesophageal color Doppler transducer, using a topical anesthesia with 10% lidocaine. The procedure was well tolerated without any complication in all patients. Transesophageal color flow Doppler has specific improved capabilities over transthoracic conventional color flow Doppler and represents an important advance even for the noninvasive evaluation of patients with suspected mitral prosthesis regurgitation.

Adult↗

Technique for superimposing a color slide onto a facial cast to sculpt a facial prosthesis.

A precise and uncomplicated technique for superimposing a color slide onto a facial cast for sculpting a facial prosthesis of the periorbital region is described. This technique allows making a facial impression with the eye closed. The superimposed slide in full-face and profile views provide a natural appearance to the facial cast. Properly selected dental and photographic materials are essential to the success of this imaginative procedure.

Humans↗

Ultraviolet radiation-induced color shifts occurring in oil-pigmented maxillofacial elastomers.

STATEMENT OF PROBLEM: Oil-based pigments are added to a maxillofacial prosthesis either as base colorants present within the elastomer or as surface tints that are painted on with an adhesive. Color stability of the pigments and pigmented prosthetic materials on exposure to ultraviolet radiation are unknown. PURPOSE: This study measured DeltaE* color changes caused by ultraviolet radiation for materials colored with 5 oil pigments, applied either as base colorants (intrinsic) or surface tints (extrinsic) to a silicone elastomer. MATERIAL AND METHODS: One of 5 oil pigments was added to polydimethyl siloxane disks to serve as a base colorant (0.2 weight percent present throughout a 2 mm thick disk) or as a concentrated surface tint (2.0 weight percent concentrated in upper 0.3 mm thickness). Pigmented disks, along with pigment-only and elastomer-only control disks, were exposed to ultraviolet radiation for 400, 600 and 1800 hours. DeltaE* color changes were measured at baseline and for each time interval. RESULTS: Control samples underwent minimum color changes after 1800 hours (DeltaE* </= 2.0), whereas samples containing oil pigments as base colorants demonstrated a wide range of susceptibility to ultraviolet radiation, with the greatest changes occurring for pigments cadmium red, cadmium yellow, and yellow ochre (7.1 </= DeltaE* </= 9.4). Elastomers coated with the same oil pigments as concentrated surface tints demonstrated significantly lower color shifting after 1800 hours of radiation exposure (maximum DeltaE* = 4.2, P </= .05). CONCLUSION: Customizing a prosthesis with an oil-pigmented surface tint may reduce the incidence of color change, provided a sufficient amount of pigment is present.

Coloring Agents↗

Applications of rapid prototyping technology in maxillofacial prosthetics.

PURPOSE: The purpose of this study was to compare the accuracy, required time, and potential advantages of rapid prototyping technology with traditional methods in the manufacture of wax patterns for two facial prostheses. MATERIALS AND METHODS: Two clinical situations were investigated: the production of an auricular prosthesis and the duplication of an existing maxillary prosthesis, using a conventional and a rapid prototyping method for each. Conventional wax patterns were created from impressions taken of a patient's remaining ear and an oral prosthesis. For the rapid prototyping method, a cast of the ear and the original maxillary prosthesis were scanned, and rapid prototyping was used to construct the wax patterns. For the auricular prosthesis, both patterns were refined clinically and then flasked and processed in silicone using routine procedures. Twenty-six independent observers evaluated these patterns by comparing them to the cast of the patient's remaining ear. For the duplication procedure, both wax patterns were scanned and compared to scans of the original prosthesis by generating color error maps to highlight volumetric changes. RESULTS: There was a significant difference in opinions for the two auricular prostheses with regard to shape and esthetic appeal, where the hand-carved prosthesis was found to be of poorer quality. The color error maps showed higher errors with the conventional duplication process compared with the rapid prototyping method. CONCLUSION: The main advantage of rapid prototyping is the ability to produce physical models using digital methods instead of traditional impression techniques. The disadvantage of equipment costs could be overcome by establishing a centralized service.

Computer-Aided Design↗

[Flexible aortic valve prostheses: long-term functional results with porcine bioprostheses without mechanical commissure stent and aortic homografts].

The long-term performance of two different types of flexible aortic prostheses was evaluated in 10 patients who received a stentless porcine prosthetic valve (group A) and in 18 patients who underwent aortic valve replacement with an aortic homograft (group B). In group A early postoperative angiography (5-16 days post surgery) revealed a mean gradient across the aortic prosthesis of 8 +/- 6 mmHg. Late postoperative Doppler echocardiography (3.2 +/- 0.9 years post surgery) suggested a mean gradient of 6 +/- 3 mmHg with a Doppler derived valve orifice area of 1.8 +/- 0.6 cm2. Color Doppler visualized mild prosthesis regurgitation in two of the 10 patients and two-dimensional imaging showed no significant leaflet calcification. In group B late postoperative Doppler echography (5.2 +/- 1.6 years post surgery) suggested a mean gradient of 11 +/- 14 mmHg with a mean graft orifice area of 1.8 +/- 0.5 cm2. Color Doppler revealed prosthesis regurgitation in 15 patients (severe 1, moderate 2, mild 12) and two-dimensional imaging visualized significant prosthesis leaflet calcification in two patients. The good hemodynamic function of a stentless porcine bioprosthesis which seems to be preserved for at least several years indicates that the use of the flexible aortic xenograft is worthwhile pursuing. The long-term performance of an aortic homograft is relatively poor and may be due to unsolved problems with regard to sterilizing and storing the valves.

Adult↗

The confusing array of tooth-colored crowns.

The venerable PFM crown or fixed prosthesis still dominates the tooth-colored restoration market. However, use of PFMs is declining slightly, as the many new all-ceramic and resin-based composite crowns and fixed-prosthesis products flood the market. Several situations may indicate the use of materials other than PFM. They include patients requiring a high level of esthetic acceptability, patients with proven or perceived allergies to the metals used in dentistry and bruxing or clenching patients with metal allergies or desire to eliminate metal from their mouths. PFM restorations have been proven during 40 years of successful use. They provide acceptable esthetics for most situations, minimal fracture during service, proven ability to serve in multiple-unit situations and excellent fit, and the profession has detailed knowledge of these restorations' advantages, disadvantages and physical characteristics. PFM restorations have only a few well-known negative characteristics. Be cautious as you elect to move from the reliability and positive history of PFM to relatively unknown types of restorations.

Bruxism↗

An evaluation of facial prostheses.

A survey was conducted to evaluate patient reactions to facial prostheses that were provided to 143 patients in the past 7 years at Roswell Park Memorial Institute. Of the 76 patients who responded, 38 patients were wearing their prostheses and 38 patients were not wearing their prostheses. Reasons cited by the patients for not using their prosthesis included lack of retention, additional surgery, discomfort, and irritation. Most of the prostheses were prepared in silicone rubber with color characterization accomplished by the tattooing method. More than 69% of the prostheses were remade within a year because of rapid changes in the defect, prosthesis material, or prosthesis color. The study revealed the need for improvement in materials, adhesive techniques, and the psychological orientation of the patient. This project was conducted at a teaching and research institute. No fees for the patients were required. Therefore our data might differ from that collected from a private practice or clinic.

Adult↗

Color changes in dry-pigmented maxillofacial elastomer resulting from ultraviolet light exposure.

Five dry pigments and one maxillofacial elastomer were evaluated for color changes (delta E) resulting from prolonged exposure to two types of ultraviolet light. The elastomer, pigments, and pigmented elastomers were subjected to each ultraviolet light source for 400, 600, and 1800 hours, and delta E color shifts were determined. The unpigmented elastomer underwent minimally perceptible color change after 600 hours of exposure to both types of ultraviolet light. Two pigments underwent substantial color change after 400 hours, whereas the remaining three pigments remained color stable after 1800 hours. It was concluded that for the materials tested, early color changes in a prosthesis may be the result of degradation of certain ultraviolet light-susceptible pigments, whereas longer term color shifts may be caused by color changes within the elastomer.

Analysis of Variance↗

The color of gingiva studied by visual color matching. Part II. Kind, location, and personal difference in color of gingiva.

A replica of natural gingival color can be fabricated in a prosthesis. A precise record of gingival color helps to follow-up oral and systemic diseases. A healthy gingival color according to the "Periodontal Workshop Committee I" is 'pink' but no indication is given for color variations by age or position. For more precise definition, therefore, gingival color was examined in the maxillary and mandibular anterior regions by visual color matching using standard color chips after Munsell's system. Gingival color was measured in 60 subjects, in 18 locations around the anterior teeth. 1. The gingival color varies in Hue from 10 RP to 2.5 YR, being mainly between 2.5 R and 5 R; in Value from 4 to 8, maximum between 6 and 7.5; and in Chroma from 1.5 to 7, mainly from 4 to 5. 2. No difference in gingival color is recognized between the male and female, or between left and right sides of the jaw. 3. Gingival color varies with the position of papillary, marginal, and attached gingivae, and the parts corresponding to different teeth have different colors. 4. The gingival color of young persons, differs markedly from that of older people. In all the parts, red Hue is more tinged with purple in the old than in the young; Value is higher in the young; and Chroma is higher in the old.

Adolescent↗

Chairside color verification for facial prostheses.

The coloring technique may be used for facial prosthetic materials that can be processed in gypsum molds. With different surface textures and varying thicknesses built into the technique, it is a reliable method for color verification of facial prosthesis before final processing.

Color↗