The inter-relation between epithelial cells of Malassez and vessels studied immunohistochemically in the periodontal membrane of human primary and permanent teeth.

BACKGROUND: Only few immunohistochemical studies have focused on the periodontal membrane in human primary teeth. Recently, studies on epithelial cells of Malassez and innervation have been published. Studies on the inter-relation between vessels and the epithelial cells of Malassez are seemingly lacking. AIM: he aim of this immunohistochemical study is to describe the histological inter-relation between epithelial cells of Malassez and vessels in the periodontal membrane close to the root surface of human primary and permanent teeth. METHODS: Twenty-nine human primary teeth and 15 permanent teeth were extracted in connection with dental treatment. The teeth were fixated, embedded in paraffin, cut in serial sections and examined immunohistochemically for epithelial cells of Malassez using wide spectrum screening and vessels using Von Willebrand Factor VIII. RESULTS: The study showed that vessels and epithelial cells of Malassez are seen parallel to the root surface. The vessels are seen on that side of the epithelial cells of Malassez, which are not facing the root surface. CONCLUSION: The vascularization appeared similar in primary and permanent teeth.

Immunolocalization of RANK and RANKL along the root surface and in the periodontal membrane of human primary and permanent teeth.

OBJECTIVE: Root resorption, impaired tooth eruption and early tooth loss have been described in relation to diseases that involve defects in the RANK-RANKL-OPG-expression. The aim of the present immunhistochemical study was to localize and compare the reactions for RANK and membrane-bound RANKL along root surfaces and in the periodontal membrane in close proximity to the root surface of human primary and permanent teeth. MATERIALS AND METHODS: The material comprised extracted human teeth (11 primary teeth and six permanent teeth) from 10 different patients. Paraffin sections were prepared of each tooth and sections of each tooth were immunohistochemically stained with antibodies specific for membrane-bound RANKL and RANK. RESULTS: The root surface and the periodontal membrane in close proximity to the root surface did not show immunoreactivity for RANKL. RANKL was only located in odontoblasts and in cells along denticles in one primary tooth. RANK was located in mononuclear cells in the pulp and in multinucleated odontoclasts along resorbed root surfaces and along resorbed dentin surfaces in the pulp in primary teeth and one permanent tooth. CONCLUSIONS: This study demonstrated RANK positivity in resorption areas in primary and permanent teeth. RANKL was positive in the pulp of one primary tooth. RANK expression in odontoclasts and RANKL expression in the pulp may indicate that RANK/RANKL play a role during resorption.

Preeruptive intracoronal resorption observed in 13 patients.

INTRODUCTION: The literature on preeruptive intracoronal resorption is sparse, comprising mainly reports of single patients. This study includes 13 patients with preeruptive intracoronal resorption, forwarded for consultation regarding diagnostics and etiology. The purposes were to determine which teeth are affected by the condition and describe how the defect is manifested radiographically. METHODS: We used visual analyses of dental or panoramic radiographs. RESULTS: The mandibular second molar appears to be the tooth that is most often affected by preeruptive intracoronal resorption. The resorption of the dentin in the molar crown was in the initial phases often seen in the medial aspects. The dentin in the crown could also be completely resorbed. The enamel contour encircling the dentin persisted as shown on the radiographs. In 1 maxillary canine, the dentin and enamel structures were completely disorganized by the resorption processes. CONCLUSIONS: Specialists in orthodontics are often the first to see radiographs of unerupted permanent teeth; therefore, they have a responsibility to be aware of the condition and refer these patients to an endodontist for treatment planning and prognosis before a decision is made regarding orthodontic treatment.

Apoptosis in the human periodontal membrane evaluated in primary and permanent teeth.

OBJECTIVE: Recent studies revealed a highly innervated layer in close proximity to the root surface in the periodontal membrane of human teeth. Persistence of the epithelial cells of Malassez along root surfaces without resorption has also been demonstrated. It is hypothesized that resorption is connected to apoptosis of the epithelial cells of Malassez. The purpose of this study is to localize cells undergoing apoptosis in the periodontal membrane of human primary and permanent teeth. MATERIALS AND METHODS: Human primary and permanent teeth were examined immunohistochemically for apoptosis and epithelial cells of Malassez in the periodontal membrane. All teeth examined were extracted in connection with treatment. RESULTS: Apoptosis was seen in close proximity to the root surface and within the epithelial cells of Malassez. This pattern of apoptotis is similar in the periodontal membrane in primary and permanent teeth. CONCLUSIONS: The inter-relationship between apoptotis and root resorption cannot be concluded from the present study. Apoptosis seen in close proximity to the root surface presumably corresponds to the highly innervated layer of the periodontal membrane. The function of this layer still needs to be elucidated.

Immunohistochemical studies of the periodontal membrane in primary teeth.

OBJECTIVES: To describe the periodontal membrane of human primary teeth immunohistochemically, while focusing on the epithelial layer of Malassez, fibers, and peripheral nerves, and to compare the findings with those of a previous study of human permanent teeth. MATERIAL AND METHODS: Nineteen human primary teeth extracted in late childhood in connection with treatment were fixed, decalcified, dehydrated, and embedded in paraffin. Paraffin sections were stained with wide spectrum screening (WSS), Vimentin, and NeuN in order to mark the epithelial layer of Malassez, fibers, and peripheral nerves. RESULTS: For root surfaces without resorption, the epithelial rests of Malassez appeared as small scattered islands. The fibers varied from tightly packed close to the root surface to a messy and loose organization. Innervation could be seen in close proximity to the root surface. The epithelial cells of Malassez were not usually seen along root surfaces with resorption. The fibers were sparse or not present. Innervation was seen in close proximity to the root. In regions with repair of resorption lacunae, the immunohistochemical reactions for epithelial cells of Malassez, fibers, and innervation pattern could be identical to those in regions with no resorption. CONCLUSION: In regions without resorption, spatial organization of the periodontal membrane of primary teeth was similar to that of permanent teeth, although the number and distribution of epithelial cells and fibers differed. In regions with repair of root resorption, the epithelial cells of Malassez, fibers, and innervation appeared as root surfaces without resorption.