Bilateral cerebellar infarction caused by dominant medial posterior inferior cerebellar artery.
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Aged↗
Biomedical subjects
G C Cho
Publications and source records attributed to G C Cho.
Identification of a resonant imaging process in apertureless near-field microscopy.
We report on apertureless near-field microscopy in the far infrared. We identify a configurational resonance of the scanning tip-surface system to be the dominating mechanism that forms the image. Experimental data such as the high imaging contrast and its spectral properties can be well explained and make the framework of a mesoscopic resonance an alternative to conventional scattering models that are used to interpret near-field data. Our findings are plausibly not restricted to the far infrared and may impact on near-field spectroscopy in general.
Journal Article↗
Predictable aesthetics with metal-ceramic and all-ceramic crowns: the critical importance of soft-tissue management.
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Crowns↗
An in vitro comparison of 5 techniques for impressing dowel space preparations.
PURPOSE: This in vitro study compared 5 different dowel space impression techniques using polyvinyl siloxane impression material to determine which method produced fewer voids in the dowel space impression. MATERIALS AND METHODS: Five techniques were used to make impressions of a prepared dowel space in a simulated endodontically treated tooth. Technique I used a 25-gauge anesthetic needle to act as a vent at the apex of the preparation to reduce voids produced during the expression of light body impression material. The anesthetic needle was removed after the impression material was injected, and an impression post was then inserted to the depth of the preparation. Twenty impressions made using this technique were compared with other techniques that used the vent without a post, no vent with a post, no vent without a post, and a lentulo spiral with a post (Techniques II through V, respectively). The percentage of impressions with voids from each group was compared to determine which technique consistently produced a void-free impression of the complete preparation length. If voids were observed in the impression, the specimen was considered inadequate. RESULTS: The percents of void-free impressions using Techniques I through V were 100%, 70%, 40%, 60%, and 20%, respectively. CONCLUSIONS: Using a 25-gauge needle as a vent while expressing impression material into the dowel space followed by placing the impression post consistently produced void-free dowel space impressions.
Dental Impression Materials↗
The science of communicating the art of esthetic dentistry. Part II: Diagnostic provisional restorations.
Provisional restorations fulfill many functions in restorative dentistry. Quality provisional restorations can provide the clinician, the patient, and the laboratory technician much valuable information prior to fabrication of the definitive restoration. Such diagnostic provisional restorations fabricated with acrylic resin are easily adjusted and modified until both esthetic and functional results are approved by the patient. Once this approval has been obtained, the definitive restorations can be fabricated with confidence, using the esthetic form of the provisional restorations as a blueprint.
Communication↗
Diametral and compressive strength of dental core materials.
STATEMENT OF PROBLEM: Strength greatly influences the selection of core materials. Many disparate material types are now recommended for use as cores. Cores must withstand forces due to mastication and parafunction for many years. PURPOSE: This study compared the compressive and diametral tensile strengths of 8 core materials of various material classes and formulations (light-cured hybrid composite, autocured titanium containing composite, amalgam, glass ionomer, glass ionomer cermet, resin-modified glass ionomer, and polyurethane). MATERIAL AND METHODS: Materials were manipulated according to manufacturers' instructions for use as cores. Mean compressive and diametral strengths with associated standard errors were calculated for each material (n = 10). Analyses of variance were computed (P <.0001) and multiple comparisons tests discerned many differences among materials. RESULTS: Compressive strengths varied widely from 61.1 MPa for a polyurethane to 250 MPa for a resin composite. Diametral tensile strengths ranged widely from 18.3 MPa for a glass ionomer cermet to 55.1 MPa for a resin composite. Some resin composites had compressive and tensile strengths equal to those of amalgam. CONCLUSION: Light-cured hybrid resin composites were stronger than autocured titanium containing composites. The strengths of glass ionomer-based materials and of a polyurethane material were considerably lower than for resin composites or amalgam.
Analysis of Variance↗
A technique to replicate soft tissues around fixed restoration pontics on working casts.
When missing maxillary incisors are replaced, the patient's primary concern is usually esthetics. Depending on the patient's smile line and the display of the incisors, the esthetic zone may extend to the entire clinical crown and include the surrounding soft tissue. For these patients, the appearance and form of the soft tissue at the base of the pontics is as critical as the esthetics of the incisal edges of the restoration. A technique is presented to precisely transfer the soft tissue morphology of the pontic area to the working cast. This modified master cast allows the laboratory technician to fabricate restorations that will harmonize precisely with the soft tissues of the patient.
Dental Impression Technique↗
Diagnostic provisional restorations in restorative dentistry: the blueprint for success.
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.
Dental Prosthesis Design↗
Contemporary evaluation of dental cements.
Today, the clinician has numerous dental cements available for luting of restorations to prepared teeth. Compared to traditional cements, many of the newer cements have improved physical properties. In this article, we analyze available cements in terms of these physical properties based on scientific data and attempts to determine their effect on long-term clinical performance. We conclude that these improved physical properties do not necessarily result in improved clinical performance. We also conclude that although these newer cements have specific clinical applications, they should not be routinely used for the cementation of metal castings because they are clearly more technique-sensitive than traditional luting agents. Zinc-phosphate cement remains the cement of choice for cementing cast gold and metal-ceramic restorations.
Biocompatible Materials↗
Soft tissue management with metal-ceramic and all-ceramic restorations.
Many advances have been made in recent years to the science and the art of metal-ceramic and all-ceramic restorations. However, no matter how natural and lifelike such restorations may be, the final esthetic result is most dependent upon the health and level of the surrounding gingival tissues. The key to success is effective soft tissue management, and the goal of this soft tissue management has been to provide healthy gingival tissues covering sound, smooth restorative margins.
Cementation↗
Rational use of contemporary all-ceramic crown systems.
There are a host of contemporary all-ceramic systems available today, as well as improved techniques for metal-ceramic restorations. Perhaps the most important factor in achieving predictable success with these restorations is excellent soft tissue management. Metal-ceramic restorations provide the most predictable service in terms of clinical longevity, versatility and prevention of wear to the opposing dentition.
Biocompatible Materials↗
Clinical experiences with bonded porcelain laminate veneers.
Bonded porcelain veneers can provide successful esthetic and functional long-term service for patients. The purpose of this article is to describe the authors' clinical experiences with veneers over the past decade and to outline the procedures required to achieve predictable success with this conservative esthetic restorative modality. It is hoped that the authors' experiences and those of others will encourage practitioners to consider more routine use of this type of restoration in many of their more complex reconstructive cases.
Dental Bonding↗
A rationale for not connecting implants to natural teeth.
When restoring partially edentulous arches with implants, there are some practitioners who believe it is occasionally beneficial to connect implants to natural teeth. This connection is performed to gain shared support from the natural tooth and implant, prevent rotation of the restoration, or sometimes merely to retain the natural tooth. A discussion and review of the literature concerning this connection is presented, and a patient treatment is shown to illustrate potential complications.
Dental Abutments↗
Replicating soft tissue contours on working casts for implant restorations.
Restoration of partially edentulous arches is often aided by the use of dental implants. When anterior edentulous spaces are restored, the clinician is challenged to provide an esthetic and functional restoration. The soft tissue that surrounds the implant restoration and the soft tissue at the base of the pontics are important factors in achieving an esthetic result. A technique is presented that will allow soft tissue morphology of both peri-implant and pontic bearing soft tissue to be incorporated into the working cast utilizing a provisional restoration. This allows the fabrication of a restoration that will harmonize with the soft tissue form of the patient.
Dental Abutments↗
An alternative altered cast technique for a distal extension removable partial denture.
The use of a removable partial denture to restore the posterior edentulous space continues to be a viable treatment option for patients who are not candidates for cantilevered fixed prostheses or dental implants because of the nature of the remaining teeth and bony support, the anatomy of the residual ridges, or financial constraints. The purpose of this paper is to introduce an alternative technique for the fabrication of a well-fitting distal extension RPD that will take maximum advantage of the dual nature of the support provided by the teeth and the resilient tissues of the residual ridge.
Acrylic Resins↗
Restoration of an anterior edentulous space.
Removable partial dentures are often overlooked as a restorative option for an anterior edentulous space. This article will focus on the advantages and disadvantages of removable prostheses for the restoration of the anterior edentulous space in specific clinical situations.
Dental Abutments↗
Materials for conservative posterior restorations.
Advantages and disadvantages of amalgam and cast gold restorations are compared to those of new tooth-colored restorations. Success can be achieved using many different types, but the benefits of traditional restorations should not be forgotten.
Bicuspid↗
The versatile and esthetic metal-ceramic crown.
The predictability, many advantages and remarkable adaptability of metal-ceramic crowns account for their frequent use. Metal-ceramic crowns will continue to be one of the most widely used dental restorations.
Bicuspid↗