Biomedical subjects

Sandra Guzmán-Armstrong

Publications and source records attributed to Sandra Guzmán-Armstrong.

3 recordsLinked to original sources

PubMed2005

Rampant caries.

Although dental caries in the pediatric and adolescent population has consistently declined in the United States, it is still the most common childhood disease. Dental problems are the number one reason for missing school next to the common cold. Dental caries are an infectious, communicable disease resulting in destruction of tooth structure by acid-forming bacteria found in dental plaque, an intraoral biofilm, in the presence of sugar. The etiology of rampant disease is very complex. It is multifactorial and has a close relationship to a number of risk factors. It is important that school nurses identify patients at risk for dental caries early to determine their risk and refer them for disease prevention and control.

Adolescent↗

PubMedDate not supplied

Surface coating and leakage of dentin-bonded resin composite restorations.

OBJECTIVES: To compare the marginal leakage of dentin-bonded resin composite restorations in tooth sections coated with nail varnish and similarly restored sections coated with cyanoacrylate cement. METHODS: MO and DO cavities were prepared with the gingival floor below the CEJ in 11 non-carious extracted human molars. Each cavity was restored with a dentin adhesive and resin composite. Sectioning yielded four specimens per tooth (N=44). One specimen from each restoration was coated with varnish. The other specimen was coated with cyanoacrylate cement. The coatings were applied to all surfaces except that a 1mm window on either side of the interproximal gingival margin was left uncoated. Specimens were thermocycled and stained with silver nitrate. Silver penetration into the gingival margin of each section was measured with a measuring microscope. The predominant leakage path for each coating type was determined by scanning electron microscopy. RESULTS: There was no significant difference between the leakage of the varnish-coated and cyanoacrylate-coated specimens. No marginal gaps were observed either by optical or by electron microscopy. However, the both optical and electron microscopy revealed leakage in nearly all specimens. This leakage was confined to either the dentin/hybrid layer interface or the adhesive resin/hybrid layer interface. CONCLUSIONS: The results suggest that these coating materials are not confounding factors in laboratory investigations of marginal leakage along dentin-bonded interfaces of resin composite restorations. Although marginal gaps were undetectable even at high magnification, leakage was observed along the gingival margin of almost all of these Class II resin composite restorations.

Bisphenol A-Glycidyl Methacrylate↗

PubMedDate not supplied

Relationship between nanoleakage and microtensile bond strength at the resin-dentin interface.

To evaluate the correlation between microtensile dentin bond strength (microTBS) and silver ion penetration, two total-etch 3-step and one self-etch 2-step system were investigated. OptiBond FL adhesive was applied to flat occlusal dentin on six non-carious human molars, and a resin composite "crown" was formed in 2 mm increments. After 24-hour water storage, the teeth were sectioned with a low-speed diamond saw to obtain four-square sticks (approximately 2 mm X 2 mm) per tooth. Cylindrical tensile test specimens were formed with an 0.5 mm2 cross-sectional area. Nail varnish was applied to the dentin within 0.5-1.0 mm of the interface before immersing in 50% silver nitrate for 15 minutes. Following silver fixation, tensile testing was performed in a Zwick UTM at 1 mm/minute using a passive gripping fixture to obtain 72-hour microTBS [23.9 MPa]. The percentage area of silver penetration was measured on debonded specimens using light microscopy and Image-Pro Plus Software [89%]. The procedures were repeated using Scotchbond Multi-Purpose Plus [microTBS = 27.8 MPa; nanoleakage = 67%] and Clearfil SE bond [microTBS = 36 MPa; nanoleakage = 55%]. No significant correlation between microtensile bond strength and nanoleakage was found for all systems. A weak-to-moderate negative relationship was found between microTBS and nanoleakage for OptiBond FL (Spearman r = -0.3844). No correlation was found for the remaining adhesive systems. The correlation between these two common laboratory measurements appears to be adhesive-system dependent.

Acid Etching, Dental↗