Enamel pearl is an ectopic enamel, which usually occurs in the root bifurcate or approaching enamel-cementum site of the first maxillary molar. A case of multiple enamel pearls on the left maxillary third molar is reported in this paper, and relevant literature was reviewed.
Dental Cementum ; Dental Enamel ; abnormalities ; Humans ; Molar ; Molar, Third ; Tooth Root

OBJECTIVETo study the clinical manifestation and its pathogenesis of the developmental enamel defects in primary dentition of children with low birth weight and premature birth history.

METHODSOne hundred and seventy-six children (aged 3-8 years old) were studied about the clinical manifestation of the developmental enamel defects in the primary dentition and its relationship with their medical history.

RESULTSThe prevalence of enamel defects in primary dentition in these children was 77.3%. There was no significant correlation between enamel defects and gender. Enamel opacity mostly affected the upper and lower second primary molars. Enamel hypoplasia mostly affected the maxillary and mandibular primary incisors and the maxillary first primary molars.

CONCLUSIONEnamel defects mainly result from children's general disorder at birth or within one year after birth.

Child ; Child, Preschool ; China ; epidemiology ; Dental Enamel ; abnormalities ; Dental Enamel Hypoplasia ; diagnosis ; epidemiology ; Female ; Humans ; Infant, Low Birth Weight ; Infant, Newborn ; Infant, Premature ; Male ; Molar ; abnormalities ; Prevalence ; Tooth, Deciduous ; abnormalities

OBJECTIVEThere is a paucity of published works that systematically evaluate gene anomalies or clinical features of patients with renal cysts and diabetes syndrome (RCAD)/maturity onset diabetes of the young type 5 (MODY5). The purpose of this review was to systematically assess the detection rate, genetic and phenotypic implications of heterozygous autosomal dominant TCF2 anomalies.

DATA SOURCESMEDLINE database was searched to select articles recorded in English from 1997 to 2008. The focus was monoallelic germline TCF2 gene mutations/deletions. Biallelic inactivation, polymorphisms, DNA modification (hypomethylation and hypermethylation), loci associated with cancer risk, and somatic TCF2 anomalies were all excluded.

STUDY SELECTIONAfter searching the literature, 50 articles were selected.

RESULTSThe detection rate of TCF2 anomalies was 9.7% and varied considerably among MODY (1.4%), renal structure anomalies (RSA) (21.4%) and RSA with MODY (41.2%) subgroups. Mutations were strikingly located within the DNA binding domain and varied among exons of the DNA binding domain: exons 2 and 4 were the hottest spots, while mutations were sporadically distributed in exon 3. The consistent phenotypes were RSA (89.6%) and diabetes mellitus (DM) (45.0%). However, the concurrence of RSA and DM was relatively low (27.5%), which hinders the optimal performance of genetic testing and obtainment of timely diagnosis. Other organ involvements were complementary and necessary for the early identification of patients with TCF2 anomalies. Analysis of phenotypes of TCF2 point mutations showed significant differences in the detection rates of RSA, impaired renal function (IRF) and DM according to mutation type but not mutation location.

CONCLUSIONThese valuable features of TCF2 anomalies that previously did not receive sufficient attention should not be neglected.

Central Nervous System Diseases ; metabolism ; Dental Enamel ; abnormalities ; metabolism ; Diabetes Mellitus ; metabolism ; Diabetes Mellitus, Type 2 ; metabolism ; Hepatocyte Nuclear Factor 1-beta ; metabolism ; Humans ; Kidney Diseases, Cystic ; metabolism

Happle-Tinschert syndrome is a disorder causing unilateral segmentally arranged basaloid follicular hamartomas of the skin associated with ipsilateral osseous, dental and cerebral abnormalities including tumors. Although a case with hemimegalencephaly was previously described, this is the first report of Happle-Tinschert syndrome with discrepant short left leg, ipsilateral skin lesions, hemimegalencephaly and frontal polymicrogyria.
Basal Cell Nevus Syndrome/diagnosis ; Child ; Dental Enamel/abnormalities ; *Frontal Lobe/pathology ; Hamartoma/*diagnosis/pathology ; Humans ; Leg Length Inequality/*diagnosis ; Magnetic Resonance Imaging ; Male ; Malformations of Cortical Development/*diagnosis ; Skin Diseases/*diagnosis/pathology ; Syndrome

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