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Biomedical subjects

N M King

Publications and source records attributed to N M King.

At least 19 recordsLinked to original sources
PubMed1999

Rewriting the "points to consider": the ethical impact of guidance document language.

Human gene transfer research has been under way for nearly 10 years, with few clinically significant results to date; yet public and professional expectations still run high. Exaggerated expectations and misconceptions about gene transfer research are attributable in part to the terminology used to describe this research, which is misleading but, in the absence of more precise language, is commonly used. In particular, use of the term "gene therapy" to describe gene transfer research and use of the term "patient" in place of "subject" tend to cause both professionals and the public to confuse research with proven effective treatment. Investigators preparing to engage in human gene transfer research must use the NIH guidance document, "The Points to Consider in the Design and Submission of Protocols for the Transfer of Recombinant DNA Molecules into the Genome of One or More Human Subjects," written by the Recombinant DNA Advisory Committee, to prepare for the submission of a research protocol. Several corrections in the terminology employed by this guidance document could help to avoid misconceptions about gene transfer research and clarify both the promise and the limits of the research enterprise for investigators and subjects.

Ethics, Medical↗
PubMed1998

The oral health of children with clefts--a review.

A review of the studies of the caries prevalence and periodontal health of patients with cleft lip and palate (CLP) revealed that only five investigations of caries prevalence in CLP patients included children. One reported that CLP children did not have a higher caries prevalence in the permanent dentition, whereas more recent studies have reported a higher caries prevalence in both the primary and permanent dentitions of CLP children than in those of noncleft children. However, there is wide variation in the teeth examined and the method of presenting data on caries prevalence. Six papers have reported on the periodontal health of adult CLP patients, and only one has done so on that of children. The adult CLP patients had poorer oral hygiene and more gingivitis, but there is no conclusive evidence that they have a higher risk of developing periodontal disease. No data on the oral hygiene of CLP children were available, but it has been emphasized that they have significantly more gingivitis than noncleft children, especially in the maxillary anterior teeth.

Adolescent↗
PubMed1998

A catalogue of anomalies and traits of the permanent dentition of southern Chinese.

Variations in size, form and morphology of the teeth can result in anomalies such as macrodontia, microdontia, hyperdontia, hypodontia, double tooth, dens evaginatus, dens invaginatus, and talon cusp. A trait may occur more commonly in certain ethnic groups. Among these traits are shovel-shaped incisors, lingual tubercle, Carabelli's trait and protostylid of the molars. Because people are traveling more frequently than ever before, and there are many migrants in different parts of the world, it is increasingly important for dental professionals to be aware of the characteristics and prevalence of the anomalies and traits that occur in the different ethnic groups, so as to be able to make valid clinical judgments and to provide the appropriate treatment. The characteristics of these anomalies and traits are presented along with the prevalence figures in the southern Chinese.

Asian People↗
PubMed1997

Ectodermal dysplasia: a review and case report.

Ectodermal dysplasia is a hereditary disease characterized by a congenital dysplasia of one or more ectodermal structures and their accessory appendages. Common manifestations include defective hair follicles and eyebrows, frontal bossing with prominent supraorbital ridges, nasal bridge depression, and protuberant lips. Intraorally, common findings are anodontia or hypodontia, conical teeth, and, consequently, generalized spacing. The patient may suffer from dry skin, hyperthermia, and unexplained high fever as a result of the deficiency of sweat glands. The present review focuses on the clinical manifestations, classifications, and diagnosis of ectodermal dysplasia. A 6-year-old girl, described in the case report, exhibited many of the manifestations of ectodermal dysplasia as well as behavioral problems and a severe gag reflex. The treatment to improve her appearance and oral function included a removable prosthesis, acid-etch-retained indirect resin composite veneers, and a fixed partial denture.

Anodontia↗
PubMed1996

A pilot study of the marginal adaptation and surface morphology of glass-cermet cements.

This study investigated changes in the marginal adaptation and surface morphology of Ketac-Silver and Chelon-Silver glass-current cements over time. Dispersalloy amalgam was used as a control. Contralateral pairs of carious primary molars were restored with the test materials and amalgam. Clinical evaluations were scheduled at 12, 18, and 24 months after placement. Gold-plated replicas of the restorations were observed with scanning electron microscopy. Fractures and cracks in the surface of the Dispersalloy and Chelon-Silver increased the surface roughness; however, the damage was superficial and self-limiting in the Dispersalloy restorations, while in Chelon-Silver the fractures caused the material to break down in layers. A substantial quantity of pores, usually smaller than 50 microns in diameter, were observed throughout the surface of the Chelon-Silver restorations. The pores in the surface of Ketac-Silver were fewer and smaller. The incidence of cavomarginal breakdown increased with time. Chelon-Silver restorations had a higher rate of cavomarginal breakdown than did Ketac-Silver and Dispersalloy restorations up to 18 months. However, there was no statistically significant difference in the marginal adaptation of the three groups at 24 months.

Cermet Cements↗
PubMed1996

Clinical performance of preventive resin restorations placed in a hospital environment.

This study was conducted retrospectively to evaluate the clinical performance of preventive resin restorations. Five hundred thirty-two restorations in 351 patients had been in the mouth for a mean of 16.5 %/- 7.6 months. The clinical performance was determined with a modified version of the US Public Health Service rating system. In 79.9% of the restorations, the marginal discoloration was rated as Alfa (no discoloration), while only 0.9% were scored as Charlie (discoloration penetrating in a pulpal direction). The marginal adaptation was rated as Oscar (fully sealed) in 28.4% of restorations; in only 0.4% of restorations, rated as Charlie or Delta, was the dentin or base exposed. In 98.3% of the restorations evaluated, the anatomic form was rated as Alfa (continuous with existing anatomic form). Recurrent caries was associated with 2.3% of the restorations. Chi-squared tests failed to reveal any statistically significant relationships between the clinical performance of the restorations and the length of time in the mouth.

Analysis of Variance↗
PubMed1994

The ectrodactyly-ectodermal dysplasia-clefting syndrome: a literature review and case report.

Ectrodactyly, atypical anhidrotic ectodermal dysplasia, and cleft lip and palate are the principal manifestations of ectrodactyly-ectodermal dysplasia-clefting syndrome. Intraorally, the common manifestations of the syndrome are hypodontia, enamel hypoplasia, and generalized microdontia. In addition, the patient may suffer from xerostomia and have a deeply fissured tongue. The oral mucosa appears, in some patients, to have an increased susceptibility to candidiasis. This case report describes a patient who exhibits many of the manifestations of the syndrome and explains ways in which many of the anomalies of the dentition can be esthetically and functionally corrected.

Abnormalities, Multiple↗
PubMed1993

Multiple supernumerary premolars: their occurrence in three patients.

The occurrence of supernumerary teeth in the premolar regions of three patients is reported. Of the 20 supernumerary teeth identified, 16 had crowns which resembled premolars and may thus be considered to be supplemental premolars, while the remainder were conical in shape. The delayed development of the supernumerary teeth in the premolar region supports the hypothesis that these teeth were part of a post-permanent dentition. The eruption of six of the eight supernumerary teeth in the 30-year-old patient demonstrated that given time some of these teeth can erupt into the dental arch.

Adolescent↗
PubMed1993

The effects of etching, micro-abrasion, and bleaching on surface enamel.

Conservative techniques for improving the appearance of discolored teeth have become popular in the past decade. These include: in-office bleaching with 30% hydrogen peroxide, which is applied on etched enamel with a gauze pad and then exposed to a bleaching light; home bleaching with a mild form of peroxide, such as 10% carbamide peroxide, which is applied on the tooth surface with custom-made mouthguards; and enamel micro-abrasion with 18% hydrochloric acid, which is applied in a pumice slurry. In this study, the in-office bleaching and enamel micro-abrasion techniques were performed on extracted teeth for investigation of their microscopic effects on the surface enamel. Specimens treated only with 37% phosphoric acid showed an enamel loss of 5.7 +/- 1.8 microns. The specimens treated with 37% phosphoric acid followed by 30% hydrogen peroxide showed enamel loss of 5.3 +/- 1.6 microns; this loss was probably not caused by the hydrogen peroxide, but rather by the etching with 37% phosphoric acid which preceded the hydrogen peroxide application. A direct application of 18% hydrochloric acid for 100 s resulted in a loss of 100 +/- 47 microns. The extent of enamel loss was much greater when the 18% hydrochloric acid was applied in a pumice slurry for the same period of time (360 +/- 130 microns), and the effect was time-dependent. Thus, the pumice and rotary prophy cup used in conjunction with the 18% hydrochloric acid contributed markedly to the loss of surface enamel, enhancing the non-selective stain-removing action of the hydrochloric acid. Therefore, the hydrochloric acid-pumice technique must be used clinically with caution.

Acid Etching, Dental↗