In vitro evaluation of the odontogenic potential of mouse undifferentiated pulp cells

The aim of this study was to evaluate the odontogenic potential of undifferentiated pulp cells (OD-21 cell line) through chemical stimuli in vitro. Cells were divided into uninduced cells (OD-21), induced cells (OD-21 cultured in supplemented medium/OD-21+OM) and odontoblast-like cells (MDPC-23 cell line). After 3, 7, 10 and 14 days of culture, it was evaluated: proliferation and cell viability, alkaline phosphatase activity, total protein content, mineralization, immunolocalization of dentin matrix acidic phosphoprotein 1 (DMP1), alkaline phosphatase (ALP) and osteopontin (OPN) and quantification of genes ALP, OSTERIX (Osx), DMP1 and runt-related transcription factor 2 (RUNX2) through real-time polymerase chain reaction (PCR). Data were analyzed by Kruskal-Wallis and Mann-Whitney U tests (p<0.05). There was a decrease in cell proliferation in OD-21 + OM, whereas cell viability was similar in all groups, except at 7 days. The amount of total protein was higher in group OD-21 + OM in all periods; the same occurred with ALP activity after 10 days when compared with OD-21, with no significant differences from the MDPC-23 group. Mineralization was higher in OD-21+OM when compared with the negative control. Immunolocalization demonstrated that DMP1 and ALP were highly expressed in MDPC-23 cells and OD-21 + OM cells, whereas OPN was high in all groups. Real-time PCR revealed that DMP1 and ALP expression was higher in MDPC-23 cell cultures, whereas RUNX2 was lower for these cells and higher for OD-21 negative control. Osx expression was lower for OD-21 + OM. These results suggest that OD-21 undifferentiated pulp cells have odontogenic potential and could be used in dental tissue engineering.

Relationship Between the Prevalence of the Dentigerous Cyst and the Odontogenic Keratocyst Tumor and the Current Etiologic Hypothesis

Cysts are considered as nonneoplastic benign lesions that, when present for a long period of time, can cause some discomfort, especially related to the treatment form. Among the types of cysts of the maxilla, the dentigerous cyst (DC) presents substances between the dental follicle and the crown of the tooth with high potential for resorption, and the odontogenic keratocyst tumor (OKT) characterizes for its noticed rapid growth pattern and the possibility to develop carcinomas in the lesion wall. The DC is the most common type among the developing odontogenic cystic lesions, while the OKT represents 10% of these lesions. The prevalence of the OKT found in the current study was superior to the DC, opposing data of the evaluated literature, as well as the predominance in relation to the age group. Dentigerous cyst cases were found mostly in younger individuals, whereas the OKT was observed mainly in individuals between the third and fourth decades of life. This fact reflects the fragility of these features while establishing the presumptive diagnosis and insinuates the strong relation with a probable genetic predisposition. In relation to sex and race, the findings in this article were similar to those found in the literature, highlighting the possibility of a hormonal involvement. However, the anatomopathologic examination remains essential to define the main diagnosis of the lesions observed by means of imaging examinations, providing for safer diagnoses to plan the treatment.

Conservative approach to the treatment of keratocystic odontogenic tumor

The odontogenic keratocyst, also known as the keratocystic odontogenic tumor, is an aggressive, intraosseous lesion of odontogenic origin that presents a high rate of recurrence. Treatment modalities include aggressive surgical procedures and more conservative approaches that significantly influence the lesion's recurrence potential. The purpose of this case report was to demonstrate a conservative approach in the treatment of an extensive keratocystic odontogenic tumor, located in the mandible's posterior region, using decompression and enucleation.

Five years follow-up of a keratocyst odontogenic tumor treated by marsupialization and enucleation: a case report and literature review

Odontogenic cysts are considered as nonneoplasic benign lesions. Among the cysts, keratocyst odontogenic tumor (KCOT) is an intra‑osseous tumor characterized by parakeratinized stratified squamous epithelium and a potential for aggressive, infiltrative behavior, and for the possibility to develop carcinomas in the lesion wall. Thus, the aim of this study was to describe a clinical case of KCOT in a young patient and discuss the treatment alternatives to solve this case. A 15‑year‑old male was referred for treatment of a giant lesion in his left side of the mandible. After the biopsy, a diagnostic of KCOT was made, and the following procedures were planned for KCOT treatment. Marsupialization was performed for lesion decompression and consequent lesion size reduction. Afterward, enucleation for complete KCOT removal was performed followed by third mandibular molar extraction. After 5 years, no signs of recurrence were observed. The treatment proposed was efficient in removing the KCOT with minimal surgical morbidity and optimal healing process, and the first and second mandibular molars were preserved with pulp vitality. In conclusion, this treatment protocol was an effective and conservative approach for the management of the KCOT, enabling the reduction of the initial lesion, the preservation of anatomical structures and teeth, allowing quicker return to function. No signs of recurrence after 5 years were observed.

Conservation of early odontogenic signaling pathways in Aves

Teeth have been missing from birds (Aves) for at least 60 million years. However, in the chick oral cavity a rudiment forms that resembles the lamina stage of the mammalian molar tooth germ. We have addressed the molecular basis for this secondary loss of tooth formation in Aves by analyzing in chick embryos the status of molecular pathways known to regulate mouse tooth development. Similar to the mouse dental lamina, expression of Fgf8, Pitx2, Barx1, and Pax9 defines a potential chick odontogenic region. However, the expression of three molecules involved in tooth initiation, Bmp4, Msx1, and Msx2, are absent from the presumptive chick dental lamina. In chick mandibles, exogenous bone morphogenetic protein (BMP) induces Msx expression and together with fibroblast growth factor promotes the development of Sonic hedgehog expressing epithelial structures. Distinct epithelial appendages also were induced when chick mandibular epithelium was recombined with a tissue source of BMPs and fibroblast growth factors, chick skin mesenchyme. These results show that, although latent, the early signaling pathways involved in odontogenesis remain inducible in Aves and suggest that loss of odontogenic Bmp4 expression may be responsible for the early arrest of tooth development in living birds.

The Expanded Human Kallikrein (KLK) gene family : genomic organisation, tissue specific expression and potential functions

The tissue kallikreins are serine proteases encoded by highly conserved multigene families. The rodent kallikrein (KLK) families are particularly large, consisting of 13 26 genes clustered in one chromosomal locus. It has been recently recognised that the human KLK gene family is of a similar size (15 genes) with the identification of another 12 related genes (KLK4-KLK15) within and adjacent to the original human KLK locus (KLK1-3) on chromosome 19q13.4. The structural organisation and size of these new genes is similar to that of other KLK genes except for additional exons encoding 5 or 3 untranslated regions. Moreover, many of these genes have multiple mRNA transcripts, a trait not observed with rodent genes. Unlike all other kallikreins, the KLK4-KLK15 encoded proteases are less related (25–44%) and do not contain a conventional kallikrein loop. Clusters of genes exhibit high prostatic (KLK2-4, KLK15) or pancreatic (KLK6-13) expression, suggesting evolutionary conservation of elements conferring tissue specificity. These genes are also expressed, to varying degrees, in a wider range of tissues suggesting a functional involvement of these newer human kallikrein proteases in a diverse range of physiological processes.