Quintessence International, 05/1991

The term remineralization of initial enamel caries is frequently used, but mainly at research conferences and in lecture rooms. Clinicians avoid discussing remineralization and white-spot enamel lesion formation with patients because details of the processes are complex. Patients, therefore, incorrectly assume that cavitation occurs right at the onset of caries and that a restoration must be placed to halt further progression of the lesion. Although laboratory and clinical studies have shown that initial white-spot enamel lesions can remineralize, patients have little or no access to this information. The schematic diagrams in this paper explain the diffusion of organic acids from plaque between enamel crystals, the partial loss of mineral from enamel crystals, and subsequent demineralization and remineralization that produces the white-spot lesion. Further, these diagrams may help clinicians explain remineralization as simply as possible to patients who present with white-spot enamel lesions.

A removable partial denture supported by resin-bonded precision attachments was constructed for a patient with intra oral symptoms of a cleidocranial dysostosis. Because of the anatomic situation, the youth, and the preprosthetic orthodontic treatment of the patient, a conventional prosthetic solution seemed inappropriate. Custom-made attachments were constructed with the spark erosion technqiue. They were fixed to the abutment teeth with resin-bonded retainers. The combination of the resin-bonding technique with the modern technology of spark erosion thus allowed a conservative approach to the oral rehabilitation of a young patient.

This study was designed to examine clinically the accuracy and reproducibility of occlusal contacts made by a computerized device (the T-scan) in ten asymptomatic subjects. The results showed 100% accuracy and reproducibility for all contacts in all subjects. A great advantage of this instrument over silk marking ribbon is that it not only records contacts but can also analyze the timing and force of each contact.

Various therapeutic techniques for the treatment of juvenile periodontitis are reported in the literature, with occasional contradictory results. One of the reasons for the contradictory results may be differences in patient selection and/or response to treatment. The following report describes the results of various treatment mo dalities, in different sites in the same individual, on localized juvenile periodontitis

A number of acids have been shown to have a peak concentration above which the rate of enamel demineralization diminishes. Citric acid, used to demineralize dentin in periodontal regenerative procedures, is one such acid. The purpose of this study was to ascertain if there were an optimal concentration of ctric acid with which to demineralize dentin. Various concentrations of ctric acid were applied to bovine dentin and then examined with atomic absorption spectophotometry to m easure the amount of calcium dissolved in each concentration. The ppm calcium/% citric acid solution rose from 0.38 ± 0.38 ppm/0% (control) to a peak of 7.54 ± 2.26 ppm/24%, then fell to 2.43 ± 0.59 ppm/80%, suggesting that there may be a peak concentration beyond which effective dentinal demineralization diminishes. The peak solution was pH = 1.42.

Two light-activated, and three heat-polymerized, resin-based veneering materials were exposed to boiled coffee, filtered coffee, or tea at 50 degrees C and evaluated for color stability. Specimens immersed in distilled water in the dark at 37 degrees C for 4 months were also assessed. One of the light-activated, resin-based veneering materials underwent intrinsic discoloration during the long-term immersion both in distilled water and in the staining solutions. The discoloration of the other materials by tea was mainly due to surface adsorption of the colorants. Discoloration by coffee was due to adsorption, and also to absorption of colorants by two of the materials investigated. This absorption and penetration of colorants into the organic phase of the veneering materials were probably due to compatibility of the polymer phase with the yellow colorants of coffee.

This study evaluated the marginal sealing ability of three of the latest generation of dentinal bonding agents following 6 months of storage in a 37 degrees C water bath. Class V preparations were placed at the cementoenamel junction of extracted human molars. Herculite XR was used to restore cavities that had been pretreated with Gluma. Tenure, or XR Bond. The restored teeth were thermally stressed every 30 days during the following 6 months, and then microleakage was assessed by dye penetration. Under the experimental conditions, the microleakage associated with XR Bond and Gluma was not statistically significantly different. XR Bond performed statistically significantly better than Tenure (a = 0.01).

A three-dimensional cavity design was used to test the bond strength between restorative materials and tooth structure. Results indicated that bonding agents that rely on mechanical retention to the dentinal smear layer produced relatively low bond strengths. Bonding agents that require smear layer modification yielded mixed results, possibly because of differences in chemical formulation. The three-dimensional cavity design employed in t his study is a replicable one, allowing the creation of standardized, clinically relevant preparations.

The diagnosis and treatment of the cracked tooth can present difficulties. The causes of the cracked tooth include masticatory accident, radical preparation and overuse of direct restorative materials, trauma from occlusion, and torque on abutment teeth. Placement of a cast restoration covering the cusp is usually suggested. However, bonded restorations are effective in restoring the strength of teeth weakened by cavity preparation. A material that bonds amalgam to dentin may present a more conservative and less expensive restoration of the cracked tooth.

Many patients with clefts that also affect the alveolar ridge present with congenital absence of the permanent maxillary lateral incisors. This paper describes the treatment of an adolescent cleft lip and palate patient whose missing and unesthetic maxillary incisors were replaced by a combination of fixed and removable partial dentures.

Voltaire, the leading French intellect of the 18th century, was a notorious hypochondriac. His numerous letters contain hundreds of references to his medical and dental disorders, as well as to those of close friends. Voltaire lived to be 84 years old, but not without suffereing from several systemic medical disorders and from periodontal disease that left him nearly edentulous by his mid-50s. His dental condition was diagnosed as a scorbutic condition, requiring systemic medication. As a result of neglect and possible mercury intoxication, his condition worsened, and he lost most of his teeth and suffered facial collapse because he did not wear a dental prosthesis. This paper recounts events in Voltaire's life that were connected to his medical and dental history, and in so doing provides a glance at medical and dental practice in 18th-century France.