NEW METHOD USING IMAGE ANALYSIS TO MEASURE GINGIVAL COLOR

For many years, observation of gingival color has been a popular area of dental research. However these methods are hard to analyze for any other than the different base conditions and colors. Thus we introduced an alternative method using image analysis to measure gingival color. For the research we performed a dental examination on 30 female students.The system is set up by aligning the camera area and facial area. The subject's chin is placed in a fixed chin cup mounted 30 cm from the camera lens. Each image is acquired such that comparison may be made with the original bite holder as well as a standard color scale. After converted to computer we used a curves dialog box for color adjustment. The curves dialog box allows adjustment of the entire tonal range of an image.The results of the analysis of the free gingiva compared to the attached gingiva are that attached gingiva was more vivid red and yellow compared to the free gingiva. In conclusion, the system described herein of digital caputre and comparison of color images, analysis and separation in three channels of free and attached ginigval surface images and matching with colorimetric scales may be useful for demonstrating the diversity of ginigval color as well as analysis of gingival health

Structural Analysis of a Repetitive Protein Sequence Motif in Strepsirrhine Primate Amelogenin

Strepsirrhines are members of a primate suborder that has a distinctive set of features associated with the development of the dentition. Amelogenin (AMEL), the better known of the enamel matrix proteins, forms 90% of the secreted organic matrix during amelogenesis. Although AMEL has been sequenced in numerous mammalian lineages, the only reported strepsirrhine AMEL sequences are those of the ring-tailed lemur and galago, which contain a set of additional proline-rich tandem repeats absent in all other primates species analyzed to date, but present in some non-primate mammals. Here, we first determined that these repeats are present in AMEL from three additional lemur species and thus are likely to be widespread throughout this group. To evaluate the functional relevance of these repeats in strepsirrhines, we engineered a mutated murine amelogenin sequence containing a similar proline-rich sequence to that of Lemur catta. In the monomeric form, the MQP insertions had no influence on the secondary structure or refolding properties, whereas in the assembled form, the insertions increased the hydrodynamic radii. We speculate that increased AMEL nanosphere size may influence enamel formation in strepsirrhine primates

Tracking Endogenous Amelogenin and Ameloblastin In Vivo

Research on enamel matrix proteins (EMPs) is centered on understanding their role in enamel biomineralization and their bioactivity for tissue engineering. While therapeutic application of EMPs has been widely documented, their expression and biological function in non-enamel tissues is unclear. Our first aim was to screen for amelogenin (AMELX) and ameloblastin (AMBN) gene expression in mandibular bones and soft tissues isolated from adult mice (15 weeks old). Using RT-PCR, we showed mRNA expression of AMELX and AMBN in mandibular alveolar and basal bones and, at low levels, in several soft tissues; eyes and ovaries were RNA-positive for AMELX and eyes, tongues and testicles for AMBN. Moreover, in mandibular tissues AMELX and AMBN mRNA levels varied according to two parameters: 1) ontogenic stage (decreasing with age), and 2) tissue-type (e.g. higher level in dental epithelial cells and alveolar bone when compared to basal bone and dental mesenchymal cells in 1 week old mice). In situ hybridization and immunohistodetection were performed in mandibular tissues using AMELX KO mice as controls. We identified AMELX-producing (RNA-positive) cells lining the adjacent alveolar bone and AMBN and AMELX proteins in the microenvironment surrounding EMPs-producing cells. Western blotting of proteins extracted by non-dissociative means revealed that AMELX and AMBN are not exclusive to mineralized matrix; they are present to some degree in a solubilized state in mandibular bone and presumably have some capacity to diffuse. Our data support the notion that AMELX and AMBN may function as growth factor-like molecules solubilized in the aqueous microenvironment. In jaws, they might play some role in bone physiology through autocrine/paracrine pathways, particularly during development and stress-induced remodeling

NEW METHOD USING IMAGE ANALYSIS TO MEASURE GINGIVAL COLOR

<p>For many years, observation of gingival color has been a popular area of dental research. However these methods are hard to analyze for any other than the different base conditions and colors. Thus we introduced an alternative method using image analysis to measure gingival color. For the research we performed a dental examination on 30 female students.</p><p>The system is set up by aligning the camera area and facial area. The subject's chin is placed in a fixed chin cup mounted 30 cm from the camera lens. Each image is acquired such that comparison may be made with the original bite holder as well as a standard color scale. After converted to computer we used a curves dialog box for color adjustment. The curves dialog box allows adjustment of the entire tonal range of an image.</p><p>The results of the analysis of the free gingiva compared to the attached gingiva are that attached gingiva was more vivid red and yellow compared to the free gingiva. In conclusion, the system described herein of digital caputre and comparison of color images, analysis and separation in three channels of free and attached ginigval surface images and matching with colorimetric scales may be useful for demonstrating the diversity of ginigval color as well as analysis of gingival health.</p

Supplementary Material for: Inductive Ability of Human Developing and Differentiated Dental Mesenchyme

The development of cell-based therapeutic strategies to bioengineer tooth tissue is a promising approach for the treatment of lost or damaged tooth tissue. The lack of a readily available cell source for human dental epithelial cells (ECs) severely constrains the progress of tooth bioengineering. Previous studies in model organisms have demonstrated that developing dental mesenchyme can instruct nondental epithelium to differentiate into enamel-forming epithelium. In this study, we characterized the ability of fetal and adult human dental mesenchyme to promote differentiation of human embryonic stem cell (hESC)-derived ECs (ES-ECs) into ameloblast-lineage cells. ES-ECs were co-cultured either with human fetal dental mesenchymal cells (FDMCs) or with adult dental mesenchymal cells (ADMCs) in either a three-dimensional culture system, or in the renal capsules of SCID mice. When co-cultured with FDMCs in vitro, ES-ECs polarized and expressed amelogenin. Tooth organ-like structures assembled with epithelium and encased mesenchyme and developing enamel-like structures could be detected in the complexes resulting from in vitro and ex vivo co-culture of ES-ECs and FDMCs. In contrast, co-cultured ES-ECs and ADMCs formed amorphous spherical structures and occasionally formed hair<i>.</i> Transcription factors were significantly upregulated in FDMCs compared to ADMCs including <i>MSX1</i>, <i>GLI1</i>, <i>LHX6</i>, <i>LHX8,</i><i>LEF1</i> and <i>TBX1</i>. In summary, FDMCs but not ADMCs had the capacity to induce differentiation of ES-ECs into ameloblast lineage cells. Further characterization of the functional differences between these two types of dental mesenchyme could enable reprogramming of ADMCs to enhance their odontogenic inductive competence