PubMed Health⌕ Search

Biomedical subjects

S B Geiger

Publications and source records attributed to S B Geiger.

6 recordsLinked to original sources
PubMed2000

Improving fissure sealant quality: mechanical preparation and filling level.

OBJECTIVE: To assess the effect of different modes of fissure preparation and filling level on the quality of pits and fissure sealants. METHODS: Various modes of fissure preparation in combination with two filling levels were examined. A total of 90 caries-free extracted human molar teeth were divided into three groups according to fissure preparation: (a) no mechanical preparation; (b) mechanical preparation with a round carbide bur; and (c) mechanical preparation with a tapered fissure diamond bur. All fissures were acid-etched and each group was subdivided according to filling level, either to the border or overfilled, using Helioseal (Vivadent, Schaan, Lichtenstein) as a sealant material. A modified microleakage assay was performed, combining occlusal loading and thermocycling, prior to staining with 0.5% Basic Fuchsin. After sectioning, teeth were examined and photographed in a reflected light microscope, sealant retention was observed and recorded. Microleakage and sealant penetration depths were measured for each section. Two-way ANOVA was used for statistical analysis. RESULTS: Sealant penetration and retention were significantly improved by mechanical preparation compared to non-prepared fissures (p<0.0001), and preparation with a tapered fissure diamond bur was superior to the round carbide bur. Overfilled fissures caused significantly higher levels of microleakage (p<0.004). CONCLUSIONS: Based on the results of this in vitro study, it is suggested that fissure sealant quality may be improved by mechanical preparation, preferably with a tapered diamond bur, and filling just to the border. Overfilling of fissures should be avoided.

Acid Etching, Dental↗
PubMed1997

Comparison between the sequential and simultaneous approaches for the restoration of adjacent proximal cavities.

The clinical situation in which several proximal carious lesions have to be treated is frequently encountered. The need to provide a cost-effective and time-effective treatment often compels the clinician to perform multiple adjacent proximal restorations simultaneously, at the same treatment session. Alternatively, such treatments may be performed sequentially in successive sessions. The different possible treatment modalities and their clinical sequel are described. Examination of the clinical results suggests that the preferred restorative procedure is the sequential one, enabling an optimal restoration of the original anatomical form, which is important for the proper health and function of the teeth and the surrounding periodontal tissues.

Dental Restoration, Permanent↗
PubMed1993

Fluoridated carbonatoapatite in the intermediate layer between glass ionomer and dentin.

The intermediate layer between a glass ionomer restoration and dentin was examined morphologically by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). SEM showed strong bonding between the dentin and glass ionomer and formation of an intermediate layer between them. FTIR spectra of successive scrapings through the ionomer/dentin interface zone showed that the intermediate layer is composed primarily of mineral fluoridated carbonatoapatite. The presence of this sparingly soluble mineral at the interface between the tooth and the restoration may provide high resistance to secondary caries and may, thus, be of great clinical importance.

Apatites↗
PubMedDate not supplied

Surface treatment of mercury-free alloys.

Finishing and polishing methods were examined for two metallic direct restorative materials being proposed as possible alternatives to amalgam, namely a gallium alloy and a consolidated silver alloy. The polished surfaces were compared to a conventional spherical amalgam (Tytin). After initial surface treatment with a 12-fluted tungsten carbide bur in a high-speed dental hand-piece, three polishing methods were evaluated: slow-speed polishing burs, rubber polishing points, and polishing disks (Sof-Lex). Each of these methods was followed by an additional surface treatment in which a pumice-flour/water slurry was applied with a rotary brush and a final surface treatment with a zinc-oxide/ethanol slurry that was applied with rotary rubber cups. The surface roughness was evaluated by profilometric measurements and light microscopy. The results showed that the smoothest surfaces for all metals were achieved with rotary finishing and polishing disks. Using the rubber points resulted in surfaces that were statistically similar to the disk-polished surfaces on all three materials. The polished surface of gallium alloy was consistently slightly rougher than that of amalgam. The consolidated silver also presented a consistently rougher surface than did amalgam, although these differences were not statistically significant. The additional polishing with pumice and zinc oxide improved the luster, but did not significantly improve the measured surface smoothness in any of the restorative materials studied.

Dental Alloys↗
PubMedDate not supplied

Characterization of dentin-bonding-amalgam interfaces.

Applying a bonding agent and a resinous adhesive layer before amalgam condensation has become a common clinical procedure. However, interactions between the different interfaces formed, and the extent of sealing obtained, have not been extensively studied. This study characterized the interfaces formed in the bonded amalgam restoration. Specifically, the individual contributions of the bonding agent (One-Step) and the adhesive resin (Resinomer) were examined, along with their mode of application on the prevention of microleakage and the formation of a tight, continuous adhesion to amalgam. To this end, a dye penetration assay and scanning electron microscopy (SEM) were used, including high resolution elemental analysis, for the characterization of the sealing properties and the interface structure obtained following various procedures of applying amalgam adhesives. Results indicated that placing bonding material under the amalgam restoration is essential to preventing microleakage. When condensed against uncured or cured adhesive material, the adhesive resinous glass layer creates a thick interface with protrusions and inclusions in the amalgam, though microleakage studies indicate that condensation over the uncured adhesive results in a better seal than that of the cured adhesive. SEM combined with elemental analysis indicates that the adhesion between amalgam and adhesive material is mainly of mechanical character and is formed by interdigitations of the adhesive material protruding into the amalgam. Gaps formed at the various interfaces in the different modalities could be localized. In addition, resinous glass composite alone, without bonding, was found to provide an unacceptable degree of sealing between the tooth and amalgam. The clinical significance of these findings is further discussed.

Analysis of Variance↗