Dennis W. Foreman

Periodontal evaluation of two mucoperiosteal flaps used in removing impacted mandibular third molars

This study compared the results of two types of access flap used in removing impacted mandibular third molars. Fifteen patients were given periodontal examinations consisting of measurements of attachment level, level of the gingival margin, and width of the masticatory mucosa at three locations around the mandibular second molars. The examinations were done preoperatively, and two, six, and 12 weeks after removal of the impacted molars. Analyses of variance indicated that there was no significant difference between the two flap techniques and, therefore, the choice of flap technique is one of operator preference. There was a significant decrease in mean sulcus depth at all measured points for either flap technique, indicating a generally healthier condition around mandibular second molars 12 weeks after the surgical removal of mandibular third molars.

Preliminary scanning electron microscope investigations of accessory foramina in the furcation areas of human molar teeth

Abstract Preliminary observations of the furcation areas of human maxillary and mandibular molars have been carried out with the scanning electron microscope in order to ascertain the size, distribution, and characteristics of the accessory canals.

An ultrastructural study of dentinal innervation in the adult human tooth

Abstract The odontoblastic process and the intradentinal nerve in the pulpal third of the dentin from permanent teeth was investigated with the electron microscope. Three types of nerve structure were observed within the predentin and dentin: bare nonmyelinated fibers, Schwann cell-sheathed fibers, and myelinated fibers. In addition, structures suggestive of synaptic or attachment sites were observed. Some structural changes were noted within the odontoblastic process themselves when certain types of nerve fiber were associated with them.

X-ray diffraction studies of as-cast high-palladium alloys

OBJECTIVES The purpose of this study was to use x-ray diffraction (XRD) to investigate four representative high-palladium alloys in the as-cast condition and obtain new information about the metallurgical phases. METHODS Two Pd-Cu-Ga alloys and two Pd-Ga alloys were cast into plate-shaped specimens (20 mm x 1.5 mm) which were bench-cooled. Polished and etched specimens were analyzed using two different x-ray diffractometers and CuKa radiation. RESULTS All four alloys exhibited strong XRD peaks for the face-centered cubic (fcc) palladium solid solution matrix, and variations in the lattice parameter were consistent with alloy compositions. Comparison of the relative peak intensities for the alloys and the pure palladium powder standard indicated that the as-cast microstructures had preferred crystallographic orientation. Because the two Pd-Cu-Ga alloys contained appreciable amounts of near-surface lamellar interdendritic or eutectic constituents, it was possible to determine previously unreported XRD peaks for the Pd2Ga phase in these alloys. Low-intensity peaks in the Pd-Ga alloys were attributed to small amounts of secondary phases observed in the microstructures. SIGNIFICANCE Knowledge of the metallurgical structures of these high-palladium alloys can be important for interpretation of microstructural observations, mechanical properties, corrosion behavior and clinical performance.

Diffusion of Strontium from Desensitizing Agents into Human Dentin as Determined by Energy-Dispersive Analysis

Strontium-containing desensitizing agents were applied to one set of tooth surfaces and were burnished onto another set of diametric surfaces. Concentration of strontium at dentin depth was determined by X-radiation dispersive analysis. Burnishing produced deeper strontium penetration. Ficks Second Law provided an estimate of relative effective time for equal strontium distributions by the two methods.

Optical Method for Articulator Comparison and Study of Occlusal Determinants

Optical and other instrumentation have been used to measure articulator movements; subsequently, specific angles were calculated, normalized, and compared for the Stuart and the Hanau XP-51 articulators in an attempt to assess the practical applicability of the latter.

Electron Microscope Comparison of Freeze-Substitution and Conventional Chemical Fixation of Undecalificied Human Dentin:

Undecalcified human dentin was prepared for electron microscopy by conventional chemical fixation with alcoholic dehydration and by freeze-substitution with cryodehydration. Comparisons are reported concerning effects of different preparation methods. Morphology remained unaltered in the pre-dentin and mineralized matrices. The technique comparison permitted inferences regarding hydration states and relative amounts of protein in different areas of the odontoblast cell.

A Method for Evaluating the Orifice Pressures of Oral Irrigation Devices

The pressures at the orifices of both self-contained and line-pressure oral irrigation devices can be evaluated with unsophisticated equipment. By measuring the height of the jet expelled by the device, the volume rate over a period of several minutes, and the area of the orifice, pressures can be measured with a precision of 2 to 4 psi. The relation between the pressure, P (psi), the density, Q, the volume expelled, V (cm3) in t (seconds), the height, h (cm) of the jet, the area, A (cm2) of the orifice, and the gravitational constant, g (cm sec-2) is