Effect of SI-R20401 to remineralize artificial incipient enamel lesions in primary teeth.

We evaluated the effectiveness of the experimental surface pre-reacted glass-ionomer coating (SI-R20401) to remineralize artificial enamel lesions in primary teeth. For each of 12 sound primary molars, five regions were assigned, based on whether enamel was unground or ground and whether PRG coating was applied. The teeth were demineralized in 10% EDTA for 7 h and lactic acid solution for 3 days and immersed in artificial saliva (Group 1), demineralizing medium (Group 2) or deionized water (Group 3) for 1 month. DIAGNOdent reading, nanoindentation test and scanning electron microcopy/energy dispersive X-ray analysis were performed. Data were analyzed using analysis of variance and the Fisher protected least significance difference test at α = 0.05. After immersion, a decrease in DIAGNOdent value for the demineralized enamel was observed only in the unground/non-PRG region of Group 1. In the ground/PRG region of Groups 1 and 3, the hardness and Young's modulus at the enamel surface were significantly higher than those at subsurface points. For unground enamel, Ca%, P%, and the Ca/P ratio at the enamel surface of the non-PRG region were significantly lower than those at subsurface points. In Group 2, scanning electron microcopy showed greater demineralization at the unground/non-PRG region compared with the unground/PRG region. Efficacy of SI-R20401 to remineralize the enamel lesions in primary teeth was partially observed, however, to arrest the lesion could not be demonstrated.

Effect of ammonium hexafluorosilicate application for arresting caries treatment on demineralized primary tooth enamel.

Ammonium hexafluorosilicate (AHF) has been applied to arrest caries without discoloration. The purpose of this study was to observe structural and elemental changes of demineralized and AHF applied primary tooth enamel. Enamel from the labial surface of 20 primary canines was divided into an unground side and ground side at the center of the tooth, and demineralized with 35% phosphoric acid for 6 min. The teeth were divided into 4 groups according to a 3-min application of AHF and 1 week of soaking in artificial saliva, as follows: group A (neither AHF nor saliva), group B (only saliva), group C (only AHF), and group D (AHF and saliva), and then subdivided according to whether the enamel was ground or unground. Specimens were analyzed with scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). The data were statistically analyzed using ANOVA and Fisher's PLSD test at α = 0.05. In groups A and B, prism structures were seen, however, in groups C and D, enamel surfaces were covered with spherical particles. Ca/P ratio was significantly higher in groups C and D than in groups A and B. There was no significant difference between ground and unground enamel in the content of any element. The values for F, Na, Mg and Si persents and Ca/P ratio were significantly higher for the enamel surface than for points 10-30 µm beneath the surface. Results of this study suggest the possibility that AHF treatment arrests caries, although further study will be required to confirm this result.

Effects of ammonium hexafluorosilicate application on demineralized enamel and dentin of primary teeth.

Silver diamine fluoride (Ag(NH(3))(2)F) arrests caries but stains teeth black. To overcome this drawback, we applied ammonium hexafluorosilicate (AHF; (NH(4))(2)SiF(6)) and observed changes in the color and structure of demineralized enamel and dentin of extracted primary teeth. Enamel and dentin were demineralized in 10% EDTA solution for 90 s followed by 35% phosphoric acid gel for 60 s, then soaked in AHF solution for 60 s. Before analysis by scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometry (EDS), enamel and dentin were demineralized in 10% EDTA for 90 s. Teeth were divided into 4 groups according to AHF application and artificial saliva immersion status and then examined. The data were statistically analyzed using one-way ANOVA and Fisher's PLSD test at a significance level of P < 0.05. AHF treatment did not cause visible discoloration. Enamel prisms and dental tubules appeared by demineralization were covered with precipitates by AHF application. A sphere-filled membranous structure was observed in the saliva immersion groups. EDS analysis showed that AHF application had no effect on enamel; however, F% and Ca/P ratio were significantly higher on dentin surfaces after AHF application without artificial saliva immersion. Further study on arresting caries treatment is required.

A case of extramedullary plasmacytoma of the larynx.

An 84-year-old male with a complaint of hoarseness was examined. A mass lesion was recognized in the false vocal fold. The tumor was excised and found to consist of atypical plasmacytes. Immunopathological examination revealed that leukocyte common antigen (CD45), UCHLI (CD45RO), CD3 and L26 (CD20) were negative and that CD79 and Vs38C were positive. Neither uric Bence-Jones protein nor serum M-protein were observed. No other bony abnormalities were recognized on X-ray examinations including both bone and Ga scintigraphy. No atypical plasmacyte infiltration was observed in bone marrow. Our final diagnosis was extramedullary plasmacytoma of the larynx. Radiotherapy was performed following surgery. The tumor did not progress to multiple myeloma and no recurrence has been observed after 2 years.