Abstract. Transforming growth factorb1 (TGFb1) reportedly causes the differentiation of fibroblasts to myofibroblasts during wound healing. We investigated the mechanism underlying the activation of latent TGFb1 released by keratinocytes in efforts to identify promising pharma cological approaches for the prevention of hypertrophic scar formation. A threedimensional col lagen gel matrix culture was prepared using rat keratinocytes and dermal fibroblasts. Stratified keratinocytes promoted the TGF receptor-dependent increase in asmooth muscle actin (aSMA) immunostaining and mRNA levels in fibroblasts. Latent TGFb1 was found to be localized suprabasally and secreted. aSMA expression was inhibited by an antia v integrin antibody and a matrix metalloproteinase (MMP) inhibitor, GM6001. In a twodimensional fibroblast culture, aSMA expression depended on the production of endogenous TGFb1 and required a v integrin or MMP for the response to recombinant latent TGFb1. In keratinocyteconditioned medium, MMPdependent latent TGFb1 secretion was detected. Applying this medium to the fibroblast culture enhanced aSMA production. This effect was decreased by GM6001, the antia v integrin antibody, or the preabsorption of latent TGFb1. These results indicate that keratinocytes secrete latent TGFb1, which is liberated to fibroblasts over distance and is activated to produce aSMA with the aid of a positivefeedback loop. MMP inhibition was effective for targeting both keratinocytes and fibroblasts in this model. [Supplementary Figure: available only at http://dx

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Three-dimensional (3D) cultures are known to promote cell differentiation. Previously, we investigated the differentiation of rat dermal fibroblasts to α-smooth muscle actin (α-SMA)-positive myofibroblasts through transforming growth factor (TGF)-β production using a 3D culture model. Here, we investigated the phenotypic change from dermal mesenchymal cells (mostly fibroblasts) to osteoblast-like cells, being inspired by the roles of smooth muscle cells or fibroblasts during vascular calcification. Spindle-shaped cells that grew in heterologous populations out of dermal explants from 2-day-old Wistar rats were cultured within a collagen matrix. α-SMA and alkaline phosphatase (ALP) messenger RNA (mRNA) levels initially increased, followed by a rise in Runx2 and osteocalcin (OCN) mRNA levels without calcification. Calcium deposits were produced in the presence of a high concentration of inorganic phosphate (2.1 mM) or β-glycerophosphate (βGP, 10 mM) after 2 weeks of culture, and both were sensitive to an inhibitor of type III phosphate transporters. An ALP inhibitor decreased only βGP-induced calcification. Inhibition of TGF-β type-I receptors attenuated ALP mRNA levels and βGPinduced calcification, suggesting that endogenous TGF-β stimulates ALP activity and then βGP breakdown. An increase in the number of cells embedded in the collagen gel enhanced the mRNA levels of Runx2 and OCN, but not of ALP. Collectively, several factors are likely to promote the differentiation of dermal mesenchymal cells into osteoblast-like cells and ectopic calcification in a 3D collagen matrix, implying the utility of these cells as a potential autologous cell source for tissue engineering.

The objective of this study was to investigate spontaneous changes in the mandibular intermolar widths concurrent with protraction facemask treatment combined with slow maxillary expansion in skeletal Class III children, and to evaluate whether slow expansion has favorable effects on maxillary protraction. Twenty-three patients were divided into expansion and non-expansion groups. The expansion group comprised 11 children (mean age, 6.9 ± 1.0 years) who underwent protraction facemask treatment combined with slow maxillary expansion. The non-expansion group consisted of 12 children (mean age, 7.8 ± 1.1 years) who underwent protraction only. Dental casts and lateral cephalograms obtained before and after protraction were used to analyze occlusal and skeletal changes during approximately 1 year of treatment. The expansion group showed significantly larger increments than the non-expansion group in all mandibular intermolar measures (P < .01). No significant differences in skeletal changes were seen for any cephalometric measures between groups. In conclusion, spontaneous increases in mandibular intermolar widths were found during maxillary protraction combined with slow expansion treatment. No favorable skeletal effects of slow expansion on protraction were confirmed.

Purpose: To establish a new coordinate system using the incisive canal and incisive foramen in cases confirmed to have root resorption in the maxillary incisor region by cone beam computed tomography (CBCT) to investigate the positions of the central and lateral incisor roots and erupting maxillary canine tooth crowns in the horizontal plane. Methods: Nine patients (two males; mean age: 10.5 years old) with suspected incisor root resorption due to erupting maxillary canines on panoramic X-ray images and in whom incisor root resorption was confirmed on CBCT images were evaluated. A control group of 12 patients with a supernumerary tooth on one side (three males; mean age: 8.6 years old) was also examined. X, Y, and Z-axes were defined, and the positions of the centers of the central incisor root (U1) and lateral incisor root (U2) and the canine cusp (U3) were examined, along with alveolar process width and length. Results: In the control group, U1, U2, and U3 were located within a certain range without overlap, while, in the incisor root resorption group, U3 overlapped with U1 and U2 and tended to deviate centrally. U2 tended to be located further posteriorly than U3. The anteroposterior diameter of the alveolar process was 1.2 mm shorter in the incisor root resorption group (p < 0.05). Conclusions: The risk of incisor root resorption accompanying canine eruption can be evaluated early by investigating the canine position on a horizontal plane established on the upper anterior tooth dentition CT images with a coordinate system using the incisive canal and incisive foramen.