Quintessence International, 10/1991

Glass-ionomer - silver cermet cement has been used extensively for restorations in children and adolescents since 1984. This work describes handling characteristics, clinical uses, and limitations of the material and documents representative examples up to 6 years after placement in the mouth. Observations about glass-ionomer - silver cermet cement in clinical use are also reported.

Difficulty often arises in fabrication of the working cast used for certain types of ceramic veneers. The desire to extend the tooih preparations far enough interproximally to achieve ideal esthetic results, but at the same time stop short of breaking proximal contact, sometimes makes sawing out individual dies impossible. This impression technique provides a method to separate dies so that laboratory procedures on adjacent teeth can be fabricated on the same working cast.

The purpose of this in vitro study was to determine the effects of three commercially available 10% carbamide peroxide solutions and a 1.5% hydrogen peroxide solution on enamel surfaces and color. The crowns of forty freshly extracted human teeth were sectioned in half incisogingivally. One half was bleached for 250 hours total treatment time. The other half of each tooth was subjected to the same protocol in distilled water solutions. The color of both the treated and control halves was determined using a colorimeter. There was no significant difference between any of the control groups, and each treated group was significantly lighter than its corresponding control group. The control and treated halves of samples of each group were then sputter coated and examined for differences in surface morphology and were compared to enamel etched with 37% phosphoric acid. No significant differeces in enamel surface texture were detected between the treated and control enamel surfaces of the teeth in any of the groups. However, the enamel surfaces in all groups differed significantly from conventionally etched enamel.

The effect of a formocresol pulpotomy of a primary tooth on the eruption pattern of the succedaneous tooth is an important consideration for long-range treatment planning. This retrospective study evaluated the eruption pattern of permanent teeth using serial radiographs of children in whom a primary molar was treated. The contralateral teeth served as controls. Twenty-seven children (14 boys and 13 girls) underwent a unilateral pulpotomy of a primary molar. In three cases, the contralateral tooth erupted earlier than the succedaneous tooth; in nine cases, both teeth erupted at approximately the same time; and in 15 cases, the succedaneous tooth erupted before the antimere. Dif ferences among the groups were statistically significant

The myelodysplastic syndromes are clonal bone marrow disorders characterized by ineffective hematopoiesis and resul tant cytopenias. Oral complications of neutropenia and thrombocytopenia include gingivitis and periodontitis, hemorrhage from the periodontium, soft tissue ulcerations, exacerbation of dental pathoses, and bacterial, fungal, and viral infections. The clinical courses and the oral complications of three patients are presented. Oral care procedures and responses are described. Speicific oral soft tissue and dental care represents an important aspect of the management of patients with myelodysplastic syndromes

Three cases of secondary retention of the first permanent molar and impaction of the adjacent second molar are reported. The clinical, radiographic, and histologic characteristics are described. In all three cases, the retained molars were in severe infra-occlusion and they may have represented a physical barrier for the impacted second molar. Early recognition of secondary retention is of great importance, because treatment of this disorder in children and adolescents is relatively simple. If secondary retention of permanent molars is not recognized before adulthood, severe malocclusion may develop, and removal of the afffected molar will be more difficult.

The purpose of this study was to evaluate the number and intensity of occlusal contacts by using the photocclusion technique in three groups receiving complete dentures with different remounting procedures. Occlusal recordings were taken with a wafer at the delivery of dentures and 1 week later. Clinical remounting seemed to be superior to laboratory remounting in the number and intensity of occlusal contacts developed during 1 week's use of dentures. Laboratory remounted dentures presented no specific advantages over dentures that had received no laboratory or clinical remount.

The purpose of this study was to determine the effects of four 10% carbamide peroxide gels on surface roughness (profilometer), lightness (colorimeter) and hardness (Rockwell) of three composite resin materials. Twenty samples of each composite resin were prepared and treated every 2 hours with fresh carbamide peroxide gel for 14 days. Only two groups had a statistically significant increase in surface roughness: Prisma APH with White & Brite and Silux Plus with Gly-Oxide. Three groups had a statis tically significant increase in lightness: Prisma APH with Gly-Oxide, Bis-Fil with Proxigel, and Bis-Fil with Gly-Oxide. Four groups had a statistically significant increase in hardness: Bis-Fil with Lighten, Bis-Fil with White & Brite, Prisma APH with White & Brite, and Prisma APH with Gly-Oxide. All these effects were minimal and probably not clinically significant.

Mesio-occlusodistal cavities were prepared in extracted human molars and restored using computer-m,achined ceramic inlays. In five groups of six restorations each, short bevels (0.5-mm) were placed either at the cervical and lateral margins or combinations of lateral, cervical, and occlusal enamel margins. An unbeveled group served as a control. In addition, the effect of inlay silanization was evaluated in two of the groups. Marginal adaptation of the inlays was assessed in the scanning electron microscope before and after a combined chemical, abrasive, thermal, and chewing load cycle test. Marginal adaptation at the enamel-composite resin interface did not differ significantly between the groups before and after the test. Marginal adaptation of the silanized ceramic interface was significantly better than that of the unsilanized ceramic (99.73% versus 76.33%). There was no correlation between the marginal width of the composite resin luting material and micromorphologic marginal quality. Dye penetration tests revealed that the cervical enamel margins were perfectly sealed; however, the cervical dentinal margins leaked in all specimens.

The purpose of this investigation was to determine the shear bond strengths of three new dentinal adhesives and to compare them to the strengths of four adhesives tudied previously. With Superbond as the adhesive, fractures occurred cohesively in the composite resin or in the bonding material. Mirage Bond fractures occurred at the interface of the adhesive and the intermediate bonding material. XR-bonding system specimens fractured at the interface of the primer and the smear layer or at the interface of the primer and the bonding material. The bond strength of Superbond was significantly greater than that of XR-bond and Mirage Bond, and XR-bond had signficiantly greater strength than did Mirage Bond. When strength values for these adhesives were compared to those from a previous study, it was found that there was no statistically significant difference between Scotchbond 2 and Superbond, none between Tenure and XR-bond, and none between Mirage Bond, Gluma, and Dentin Adhesit.