Dental Pulp Cavity ; abnormalities ; Humans ; Maxilla ; Molar ; abnormalities

Dental Pulp Cavity ; abnormalities ; pathology ; Humans ; Root Canal Therapy ; methods

Dens invaginatus is a rare developmental anomaly of the teeth that is caused by the infolding of enamel organs or the penetration of their proliferations into dental papillae before calcification has occurred. The presence of double dens invaginatus is extremely rare. This paper describes the use of cone beam computed tomography in the evaluation of a maxillary lateral incisor with double dens invaginatus and periapical periodontitis. The tooth was treated through microscopic root canal therapy. The tooth was free of clinical symptoms, and the periradicular lesion narrowed during the follow-up period of 1 year.
Humans ; Dental Pulp Cavity/abnormalities* ; Dens in Dente/pathology* ; Incisor/pathology* ; Root Canal Therapy ; Periapical Periodontitis/pathology*

Double tooth is a dental anomaly consequent to fusion of two or more teeth or gemination of a single tooth. This report describes a unique case of double tooth in relation to a mandibular lateral incisor exhibiting the presence of four root canals. The role of conventional radiography and advanced three-dimensional imaging techniques in the better assessment of complex root canal systems and their aid in endodontic management has also been highlighted.
Dental Pulp Cavity ; Fused Teeth ; Imaging, Three-Dimensional ; Incisor ; Multidetector Computed Tomography ; Tooth ; Tooth Abnormalities ; Tooth, Supernumerary

Deletion or mutation of dentin matrix protein 1 (DMP1) leads to hypophosphatemic rickets and defects within the dentin. However, it is largely unknown if this pathological change is a direct role of DMP1 or an indirect role of phosphate (Pi) or both. It has also been previously shown that Klotho-deficient mice, which displayed a high Pi level due to a failure of Pi excretion, causes mild defects in the dentinal structure. This study was to address the distinct roles of DMP1 and Pi homeostasis in cell differentiation, apoptosis and mineralization of dentin and enamel. Our working hypothesis was that a stable Pi homeostasis is critical for postnatal tooth formation, and that DMP1 has an antiapoptotic role in both amelogenesis and dentinogenesis. To test this hypothesis, Dmp1-null (Dmp1(-/-)), Klotho-deficient (kl/kl), Dmp1/Klotho-double-deficient (Dmp1(-/-)/kl/kl) and wild-type (WT) mice were killed at the age of 6 weeks. Combinations of X-ray, microcomputed tomography (μCT), scanning electron microscopy (SEM), histology, apoptosis and immunohistochemical methods were used for characterization of dentin, enamel and pulp structures in these mutant mice. Our results showed that Dmp1(-/-) (a low Pi level) or kl/kl (a high Pi level) mice displayed mild dentin defects such as thin dentin and a reduction of dentin tubules. Neither deficient mouse line exhibited any apparent changes in enamel or pulp structure. However, the double-deficient mice (a high Pi level) displayed severe defects in dentin and enamel structures, including loss of dentinal tubules and enamel prisms, as well as unexpected ectopic ossification within the pulp root canal. TUNEL assay showed a sharp increase in apoptotic cells in ameloblasts and odontoblasts. Based on the above findings, we conclude that DMP1 has a protective role for odontoblasts and ameloblasts in a pro-apoptotic environment (a high Pi level).
Ameloblasts ; pathology ; Amelogenesis ; physiology ; Animals ; Apoptosis ; physiology ; Cell Differentiation ; physiology ; Dental Enamel ; pathology ; Dental Pulp ; pathology ; physiology ; Dental Pulp Cavity ; pathology ; Dentin ; abnormalities ; pathology ; Dentinogenesis ; physiology ; Extracellular Matrix Proteins ; genetics ; physiology ; Glucuronidase ; genetics ; Homeostasis ; physiology ; Hyperphosphatemia ; physiopathology ; Immunohistochemistry ; Mice ; Mice, Knockout ; Microscopy, Electron, Scanning ; Odontoblasts ; pathology ; Odontogenesis ; physiology ; Ossification, Heterotopic ; genetics ; pathology ; Phosphates ; physiology ; Tooth Calcification ; physiology ; X-Ray Microtomography