By using a scanning electron microscope (SEM) fitted with a backscattered electron (BSE) detector, 'prismless' enamel was observed in the surface layers of permanent teeth. The composite images of the BSE can reveal prism shapes with no etchings because prism sheaths show a lower value of the BSE emission than prism bodies and tails or the interprismatic regions. Thus, the enamel showing a uniformal BSE image was identified as a 'prismless' structure. The surface 'prismless' enamel was classified into three different shapes containing indistinct and stunted prism structures as well as that of the secondary electron (SE) images by SEM following acid and EDTA etching; in addition, the subsurface 'prismless' zones connected with the surface 'prismless' enamel were clearly found.
Anodic oxidation of titanium in a H3PO4/H2O2 solution using alternating current was investigated. Treated titanium specimens served as both an anode and a cathode, and potential was applied up to 130 V. Surface films with different interference colors were formed on titanium as a function of the applied voltage. Adhesion of the surface film to the parent titanium metal was excellent. XPS analysis suggested that titanium phosphate with bound water was formed in the outermost surface, and titanium oxide (TiO2) was formed in the following outer surface. The thickness of the surface oxide film was approximately 3,000 Å at AC 100 V. X-ray diffractory analysis revealed that amorphous anatase (Ti02) was formed by anodic oxidation which was crystallized after heat treatment.
Anodic oxidation is a popular method to deposit an oxide film on titanium with a thickness on the order of several hundred nm. In this study formation and some properties of anodic films of titanium under discharge conditions were investigated. Treated titanium specimens served as an anode in several electrolytes, and voltage was applied using the direct current power source. The discharge threshold voltage in each electrolyte decreased as the concentration of the electrolyte increased. Anodic oxidation of titanium was carried out on applying the voltage above the discharge threshold voltage, for example, at 100-130 V for a phosphoric acid solution (30 wt. %). Surface films with a thickness on the order of pm were formed by this treatment. Adhesion of the oxide film was superior when the anodic oxidation was carried out under moderate discharge conditions. SEM observations appeared the featured microscopic surface topography with many small (pm order) holes on the surface of the specimen treated by anodic oxidation under discharge conditions. X-ray diffractory analysis revealed that titanium oxides (TinO2n-1) and an amorphous anatase (TiO2) were formed by the anodic oxidation under discharge conditions.
A case of primary hyperparathyroidism with dull pain of the temporomandibular joint and limitation of mandibular movement is described. These symptoms appeared after the patient had luxation of the left mandibular condyle in 1971. Radiographs of jaws and teeth did not disclose significant abnormalities except for erosion of the left condyle. Immunological and biochemical investigations of serum revealed that the patient suffered from primary hyperparathyroidism.