Objectives:This study investigated the titratable acidity and erosive potential of acidic agents on the microhardness and surface micromorphology of four restorative materials.Methods:Forty-seven discs of each restorative material; metal-reinforced glass ionomer cement (Ketac-S), resin-modified glass ionomer cement (Fuji II LC), resin composite (Filtek Z250) and amalgam (Valiant-Ph.D.), 12 mm in diameter and 2.5 mm in thickness, were divided into four groups (5 discs/group). Specimens were then immersed for 7 days into four storage media; deionized water (control), citrate buffer solution, green mango juice and pineapple juice. Microhardness testing before and after immersions was performed. Micromorphological changes were evaluated under a scanning electron microscope (SEM). Statistical significance among each group was analyzed using two-way repeated ANOVA and Tukey’s tests.Results:The Fuji II LC and the Ketac-S showed the highest reduction in microhardness (P<.05). The Valiant-Ph.D. and the Filtek Z250 showed some minor changes over the period of 7 days. The mango juice produced the greatest degradation effect (P<.05).Conclusions:This study suggested that for restorations in patients who have tooth surface loss, materials selected should be considered. In terms of materials evaluated, amalgam and resin composite are the most suitable for restorations.

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The acidic agents used in this study affected the microhardness and elemental dissolution of ceramics. The main elemental compositions of ceramics (silicon, aluminium and potassium) decreased after being immersed in acidic agents.

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This study was conducted to evaluate the titratable acidity and effect of naturally acidic agents on the surface microhardness, elemental composition, and surface morphology of fluorapatite-leucite ceramics. One hundred and ten ceramic disks (IPS d.SIGN), 12.0 mm in diameter and 2.0 mm in thickness, were fabricated. Before immersion, the baseline data of Vickers microhardness and elemental composition were recorded. Four groups were immersed in acidic agents (citrate buffer solution, green mango juice, and pineapple juice) and deionized water (control) at 37ºC for 168 hours, whereas one group was immersed in 4% acetic acid at 80ºC for 168 hours. After immersion, specimens were evaluated and data were analyzed using one-way repeated ANOVA and Tukey's test (α=0.05). Microhardness values significantly decreased after immersion (p<0.05). In terms of elemental composition, the weight percentages of silicon, potassium, aluminum, and sodium also decreased after immersion (p<0.05). Results of this study showed that fluorapatite-leucite ceramics were affected by long-term immersion in acidic agents.

The purpose of this study was to evaluate the possible risk factors connected with tooth wear. Using the Tooth Wear Index (TWI) and the charting of pre-disposing factors tooth surface loss was recorded in 506 patients, of the Dental Hospital, Prince of Songkla University. We found that age, sex, number of tooth loss, frequency of alcohol, sour fruit and carbonate intake were significant risk factors. Regarding the tooth position, the first molar showed the greatest degree of wear, while the canine and premolar showed the least, respectively. The occlusal surface showed the greatest wear and the cervical, lingual and buccal surfaces showed the least, respectively.

Osteoporosis is widely recognized as a major health problem caused by an inappropriate rate of bone resorption compared to bone formation. Previously we showed that d-pinitol inhibits osteoclastogenesis but has no effect on osteoblastogenesis. However, the effect on osteoblast differentiation of its isomer, l-quebrachitol, has not yet been reported. The purpose of this study was, therefore, to investigate whether l-quebrachitol promotes the osteoblastogenesis of pre-osteoblastic MC3T3-E1 cells. Moreover, the molecular mechanism of action of l-quebrachitol was further explored. Here, it is shown for the first time that l-quebrachitol significantly promotes proliferation and cell DNA synthesis. It also enhances mineralization accompanied by increases in mRNA expression of bone matrix proteins including alkaline phosphatase (ALP), collagen type I (ColI), osteocalcin (OCN), and osteopontin (OPN). In addition, l-quebrachitol upregulates the mRNA and protein expression of bone morphogenetic protein-2 (BMP-2) and runt-related transcription factor-2 (Runx2), while down-regulating the receptor activator of the nuclear factor-κB ligand (RANKL) mRNA level. Moreover, the expression of regulatory genes associated with the mitogen-activated protein kinase (MAPK) and wingless-type MMTV integration site (Wnt)/β-catenin signaling pathways are also upregulated. These findings indicate that l-quebrachitol may promote osteoblastogenesis by triggering the BMP-2-response as well as the Runx2, MAPK, and Wnt/β-catenin signaling pathway.

Background/purpose: The potential erosive effects of acidic foods, sour fruits, and drinks on enamel have been extensively investigated. However, their effects on fluorapatiteeleucite porcelain restorations have not been widely examined. The purpose of this study was to evaluate the ion leaching and surface roughness of porcelain immersed in acidic agents. Materials and methods: One-hundred and forty-five discs (12.0 mm in diameter and 2.0 mm thick) were made from fluorapatiteeleucite porcelain (IPS d.SIGN). Baseline data of the elemental compositions of all storage agents and the surface roughness of specimens were recorded. Four groups of discs were then immersed in acidic agents (citrate buffer solution, pineapple juice, and green mango juice) and deionized water (the control) at 37 C for 168 h. One group was immersed in 4% acetic acid at 80 C for 168 h. After immersion, the ion leaching from solutions of all specimens for each acidic agent was measured by inductively coupled plasma optical emission spectroscopy. The surface roughness was evaluated under a profilometer. Surface characteristics of specimens were examined under a scanning electron microscopy (SEM). Data were analyzed using one-way repeated analysis of variance (ANOVA) and Tukey's multiple comparisons (a Z 0.05). Results: Fluorapatiteeleucite porcelain discs exhibited significant leaching of various ions to varying degrees and increased in roughness after being immersed in acidic agents (P < 0.05). SEM photomicrographs also indicated destruction of the surface of the porcelain discs.