Composite resin in medicine and dentistry.

Composite resin has been used for nearly 50 years as a restorative material in dentistry. Use of this material has recently increased as a result of consumer demands for esthetic restorations, coupled with the public's concern with mercury-containing dental amalgam. Composite is now used in over 95% of all anterior teeth direct restorations and in 50% of all posterior teeth direct restorations. Carbon fiber reinforced composites have been developed for use as dental implants. In medicine, fiber-reinforced composites have been used in orthopedics as implants, osseous screws, and bearing surfaces. In addition, hydroxyapatite composite resin has become a promising alternative to acrylic cement in stabilizing fractures and cancellous screw fixation in elderly and osteoporotic patients. The use of composite resin in dentistry and medicine will be the focus of this review, with particular attention paid to its physical properties, chemical composition, clinical applications, and biocompatibility.

Dental amalgam restorations: daily mercury dose and biocompatibility.

Over the past 150 years, silver-tin-copper amalgam has been the most frequently used dental restorative material. Amalgam may be the single most frequently used implant material. In the early 1980s, researchers discovered that amalgam restorations release mercury vapor during chewing. This review describes the research that has led to an estimate of the daily dose of mercury that will be absorbed by a subject with a large number of amalgam restorations. Along the way, the history and chemistry of dental amalgam are outlined. The routes of absorption of liquid mercury, ionic mercury, organic mercury, and mercury vapor are also briefly described. The daily dose is found to be 14% of the threshold above which observable adverse neurological symptoms are expected. The review concludes with a summary of the research on the adverse effects of dental amalgam. As expected from the low daily dose, few adverse neurological symptoms have been reported. There is also little evidence of an association of amalgam restorations with neurodegenerative diseases, altered renal function, adverse pregnancy outcomes, or autoimmune diseases. There is a lack of data on neurobiological and neurodevelopmental effects on children who may be exposed to mercury from maternal amalgam restorations during gestation. Additional data on the role of amalgam, if any, in Alzheimers disease and multiple sclerosis are needed.

PMMA: an essential material in medicine and dentistry.

The first use of polymethyl methacrylate (PMMA) as a dental device was for the fabrication of complete denture bases. Its qualities of biocompatibility, reliability, relative ease of manipulation, and low toxicity were soon seized upon and incorporated by many different medical specialties. PMMA has been used for (a) bone cements; (b) contact and intraocular lens; (c) screw fixation in bone; (d) filler for bone cavities and skull defects; and (e) vertebrae stabilization in osteoporotic patients. The many uses of PMMA in the field of medicine will be the focus of this review, with particular attention paid to assessing its physical properties, advantages, disadvantages, and complications. Although numerous new alloplastic materials show promise, the versatility and reliability of PMMA cause it to remain a popular and frequently used material.

Surgical endodontic retrograde root-end filling materials.

The treatment of diseased and necrotic pulpal tissue in teeth spans has been well known throughout history. Root canal treatment in the twentieth century has included complete removal of pulpal remnants to remove the failing tissue and then obturating the canal space with biocompatible material. This treatment preserves individual teeth to further function as part of a whole dentition for the patient's well-being. Failed root canal treatment, however, sometimes requires surgical intervention to treat the teeth from the root end. This article reviews the materials placed in intimate contact with tissues in this surgical procedure. The implications of these various materials within the tissues are discussed, along with clinical signs and symptoms a healthcare provider might encounter when examining these patients. There is no clear-cut "best" material for root-end surgical obturation at this time. Therefore, major materials that might be used are included in this discussion.

Survey of undergraduate esthetic courses in U.S. and Canadian dental schools.

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.

Underserved region recruitment and return to practice: a thirty-year analysis.

The purpose of this investigation was a retrospective analysis of a select group of graduates from the University of Kentucky College of Dentistry (UKCD) over a thirty-year history to determine how many of these individuals came from the Appalachian Region of Eastern Kentucky, which historically has been economically depressed and underserved by health care practitioners including dentists. This same group of dental school graduates was then tracked to see if they established dental practices in the Appalachian region of the state. Recruiting trends were investigated by reviewing student records regarding county of origin from targeted classes at UKCD in 1969, 1979, and 1989 to gain ten-year incremental, historical perspectives. To identify more recent trends, classes graduating in 1994 through 1999 were reviewed. Once identified, the databank of the Kentucky Board of Dentistry was used to determine if these individuals reported practicing in counties of Kentucky designated by the Appalachian Regional Commission (ARC). The findings of this study indicate an alarming decline both in numbers of students being recruited from this underserved area and a concomitant decline in those recruits returning to ARC-designated counties in the state. This study establishes the need for persistent diligence in recruitment of students from underserved areas and challenges dental schools to create strategies that will encourage their graduates to establish practices in these regions.