RESUMO
Objective@#To investigate the effect of a nanohydroxyapatite suspension with a 10% mass fraction on enamel demineralization after adjacent enamel removal and to provide a reference for the clinical use of nanohydroxyapatite to prevent enamel demineralization after adjacent enamel removal. @*Methods @#Forty fresh extracted premolars were incised from the coronal surface of the crown after glazing and polishing with sand strips. Each tooth was made into two specimens. Eighty teeth were randomly divided into four groups: a blank group, a dolofluoride group, a dental mousse group and a 10% nanohydroxyapatite group. After 30 days of pH cycling in vitro, a microhardness tester was used to detect the enamel surface elements before and after deglazing treatment. Scanning electron microscopy (SEM) and X-ray energy dispersive spectrometry (EDS) were used to analyze the enamel surface elements. @*Results@#After the experiment, the microhardness values of the adjacent glazed specimens of the four groups were (128.18 ± 6.89) kg/mm2 in the blank group, (216.75 ±9.87) kg/mm2 in the dolefluoride group, (198.88 ± 4.76) kg/mm2 in the dental care group and (218.44 ± 7.88) kg/mm2 in the 10% nanohydroxyapatite group, which were significantly different (F=189.14, P＜ 0.001). The LSD-t test showed that there was no significant difference between the dolefluoride group and the 10% nanohydroxyapatite group (P＜ 0.05), but the differences between the other groups were statistically significant (P > 0.05). There were significant differences in the Ca/P ratio among the blank group (1.39 ± 0.08), the dolefluoride group (1.70 ± 0.11), the dental care group (1.54 ± 0.12) and the 10% nanohydroxyapatite group (1.71 ± 0.14) (F=10.539, P＜ 0.001). There was no significant difference between the dolefluoride group and the nanohydroxyapatite group after the experiment (P > 0.05), but there were significant differences among the other groups (P＜ 0.05).@*Conclusion @#Dolerofluoride, dental protector and 10% nanohydroxyapatite can promote remineralization of enamel after enamel removal. The remineralization induced by 10% nanohydroxyapatite is similar to that induced by dolerofluoride.
RESUMO
<p><b>BACKGROUND</b>On May 12, 2008, a major earthquake hit Wenchuan County in Sichuan Province of China. The number of cases of crush injury following this event was high. Ultrasonic appearance of rhabdomyolysis (RM) caused by crush injury in the Wenchuan earthquake was observed to evaluate the diagnostic value of ultrasound for detection of rhabdomyolysis.</p><p><b>METHODS</b>We analyzed clinical and ultrasonic manifestations of 50 cases of RM and 18 cases of RM with osteofascial compartment syndrome (OCS). All cases were caused by crush injury in the Wenchuan earthquake. For these RM patients, we also evaluated the correlations between creatine kinase (CK) and the scope of the muscle lesions as observed by ultrasound.</p><p><b>RESULTS</b>There were differences in clinical symptoms, physical signs and ultrasonic appearance between the two groups of patients. The ultrasonic characteristics of the RM were as follows: the striated muscle in the lesions thickened with good overall continuity, and the muscle texture was vague; the strength of the echo was uneven and the echo was cloudy or ground glass-like. Liquid dark zones appeared between muscles and were spindle-like or irregular in shape. There were no blood flow signals in the liquid dark areas. The volume of the striated muscle increased in patients with OCS; the fascia wrapping the muscle showed arched protrusions and significant displacement. The flow velocity of the distal arteries decreased and the spectrum was abnormal. The muscle lesion scope of RM group and RM and OCS group was (7.8 +/- 2.0) cm and (13.6 +/- 3.1) cm, respectively. The correlation coefficient (r) between the muscle lesion scope and the CK was 0.681 for the RM group (P < 0.05) and 0.516 for the RM and OCS group (P < 0.05).</p><p><b>CONCLUSIONS</b>The ultrasonogram of RM has characteristic manifestations and can provide important information for clinical diagnosis and treatment of rhabdomyolysis.</p>