Concrescence: assessment of case by periapical radiography, cone beam computed tomography and micro-computed tomography.

The aim of this article was to describe imaging aspects of concrescence analyzed by three imaging modalities. A second molar joined together with a third molar was imaged using digital periapical radiography, cone beam computed tomography (CBCT) and micro-computed tomography (Micro-CT). On periapical radiograph, the mesial root of the third molar is superimposed on the distal root of the second molar. On CBCT images, a large cementum union between bulbous roots was detected, confirming the diagnosis of concrescence. On micro-CT images, the cementum union appeared limited to the apical third of the roots. In conclusion, both computed tomography modalities allowed for the diagnosis of concrescence. However, only micro-CT provided the real extension of the cementum union.

Hypoplastic root cementum and premature loss of primary teeth in Coffin-Lowry syndrome: a case report.

BACKGROUND: Coffin-Lowry syndrome (CLS) is a rare genetic disorder. The syndrome presents with psychomotor retardation, short stature, skeletal deformations, digit abnormalities, and distinctive facial features. Oral and dental findings in CLS are common and they include thick prominent lips, high palate, midline lingual furrow, hypodontia, microdontia, delayed eruption, and early tooth loss. Only one earlier case suggesting hypoplastic root cementum as cause for primary loss of teeth in CLS has been published. CASE REPORT: This case describes a 3-year-old boy with premature loss of primary incisors without preceding root resorption. In addition to the dental findings, the boy had several general signs and symptoms and the dental findings together with the other characteristics led to the clinical diagnosis of CLS, which later was genetically verified. Histological analysis of an extracted primary incisor showed hypoplastic root cementum. CONCLUSION: Hypoplastic root cementum may explain early tooth loss in CLS. As early loss of primary teeth is rare, especially when there is no previous root resorption, the individual is likely to seek dental care. Thus, the dentist may play an important role in assisting in the diagnosing of CLS.

Familial hypophosphatemic rickets.

Rickets is the failure of mineralization of osteoid and newly formed bones in a child skeleton. It is commonly associated with vitamin D deficiency; however, it can be because of a decrease in the serum phosphate levels leading to inadequate mineralization of cartilage and bone, consequent skeletal deformities, and growth retardation. The hypophosphatemic conditions that interfere in bone mineralization comprise many hereditary or acquired diseases. One of the hereditary types of hypophosphatemic rickets is the familial hypophosphatemic rickets. This rare variety was diagnosed in a 9-year-old patient who had come with a chief complaint of a missing tooth. In the present case, radiographic aspects of oral and systemic manifestations of familial hypophosphatemic rickets are highlighted.

Aberrant cementum phenotype associated with the hypophosphatemic hyp mouse.

BACKGROUND: Cementogenesis is sensitive to altered local phosphate levels; thus, we hypothesized a cementum phenotype, likely of decreased formation, would be present in the teeth of X-linked hypophosphatemic (Hyp) mice. Mutations in the phosphate-regulating gene with homologies to endopeptidases on the X chromosome (Phex) cause X-linked hypophosphatemia, characterized by rickets, osteomalacia, and hypomineralized dentin formation, a phenotype recapitulated in the Hyp mouse homolog. Here, we report a developmental study of tooth root formation in Hyp mouse molars, focusing on dentin and cementum. METHODS: Light and transmission electron microscopy were used to study molar tissues from wild-type (WT) and Hyp mice. Demineralized and hematoxylin and eosin-stained tissues at developmental stages 23 to 96 days postcoital (dpc) were examined by light microscopy. Immunohistochemistry methods were used to detect bone sialoprotein (BSP) distribution in Hyp and WT mouse molar tissues, and transmission electron microscopy was used to study similar molar tissues in the non-demineralized state. RESULTS: Dentin in Hyp mice exhibited mineralization defects by 33 dpc, as expected, but this defect was partially corrected by 96 dpc. In support of our hypothesis, a cementum phenotype was detected using a combination of immunohistochemistry and transmission electron microscopy, which included thinner BSP-positive staining within the cementum, discontinuous mineralization, and a globular appearance compared to WT controls. CONCLUSION: Mutations in the phosphate-regulating Phex gene of the Hyp mouse resulted in defective cementum development.

Root surface characteristics of children teeth with periodontal diseases.

The present study examined the root surfaces of teeth from children with or without periodontal diseases and with or without systemic diseases. Light microscopy revealed that when compared to control teeth: teeth with chronic periodontitis had similar radicular histology; teeth from children with leukocyte adhesion deficiency, Down syndrome and aggressive periodontitis had narrower cementum areas; teeth from children with hypophosphatasia showed cementum aplasia. Cementum anomalies may facilitate the establishment and progress of periodontitis in children.

An overview of the dens invaginatus with case examples.

Dens invaginatus is an uncommon dental anomaly in which there is a deepening of the cingulum with infolding of the enamel and dentine. The severity varies, from mild extension into the pulp cavity, to extreme forms in which the invagination extends through the root, resulting in a second opening at or near the apex, and complex morphology. The following cases report on the different management approaches to dens invaginatus and illustrate the difficulties encountered in managing such cases.

Concrescence: report of rare complication.

Concrescence is an uncommon developmental anomaly that may influence exodontia as well as periodontal, endodontic, orthodontic and even prosthodontic diagnosis and treatment planning. Unexpected complications arising from this condition may lead to legal complications. To minimize risk and adverse outcome of treatment, consideration should be given to recognizing this condition and, possibly, modifying treatment planning. This article presents an unsuspected case of concrescence with a review of the literature.

Concrescence of a mandibular third molar and a supernumerary fourth molar: report of a rare case.

Concrescence represents a rare developmental anomaly in which two fully formed teeth are joined along the root surfaces by cementum. Maxillary molars are the teeth most frequently involved, especially a third molar and a supernumerary tooth. Very few cases have been reported about the concrescence of a third molar and a supernumerary tooth. According to our current knowledge, this case report is the first in the literature in which concrescence is observed between a third molar and a supernumerary fourth molar in the mandible.

Florid cemento-osseous dysplasia in a young Indian woman. A case report.

We present a rare case of florid cemento-osseous dysplasia (FCOD) occurring in a 27-year-old Indian woman. She presented with three lesions, two of them symmetrical, at the posterior region of the mandible. Another lesion appeared nine months later, symmetrical to the existing third lesion. This confirmed the diagnosis of florid cemento-osseous dysplasia as being symmetrical asymptomatic bone lesions occurring in the jaw. The diagnosis was made radiographically depending on a series of radiographs, as biopsy is contraindicated. No treatment was required as the lesions were asymptomatic, causing no problem to the patient. The patient continues to be reviewed annually. The case is rare in its unusual combination of the disease itself (FCOD), age (27 years) and race (Indian). Clinical and radiological features are presented.

An association of external and internal enamel pearls.

We report a rare case of an association of external enamel pearl with internal enamel pearl on the root of a molar. To the best of our knowledge, association of external and internal enamel pearls has not been previously reported. We discussed the histogenesis of enamel pearls and proposed that internal enamel pearl formation may be a continuation of formation of external enamel pearl.

Dental Abnormalities Caused by Novel Compound Heterozygous CTSK Mutations.

Cathepsin K (CTSK) is an important protease responsible for degrading type I collagen, osteopontin, and other bone matrix proteins. The mutations in the CTSK gene can cause pycnodysostosis (OMIM 265800), a rare autosomal recessive bone dysplasia. Patients with pycnodysostosis have been reported to present specific dental abnormalities; however, whether these dental abnormalities are related to dysfunctional CTSK has never been reported. Here we investigated the histologic changes of cementum and alveolar bone in a pycnodysostosis patient, caused by novel compound heterozygous mutations in the CTSK gene (c.87 G>A p.W29X and c.848 A>G p.Y283C). The most impressive manifestations in tooth were extensive periradicular high-density clumps with unclear periodontal space by orthopantomography examination and micro-computed tomography scanning analysis. Hematoxylin/eosin and toluidine blue staining and atomic force microscopy analysis showed that the cementum became significantly thickened, softened, and full of cementocytes. The disorganized bone structure was the main character of alveolar bone. The p.W29X mutation may represent the loss-of-function allele with an earlier termination codon in the precursor CTSK polypeptide. Residue Y283 is highly conserved among papain-like cysteine proteases. Three-dimensional structure modeling analysis found that the loss of the hydroxybenzene residue in the Y283C mutation would interrupt the hydrogen network and possibly affect the self-cleavage of the CTSK enzyme. Furthermore, p.Y283C mutation did not affect the mRNA and protein levels of overexpressed CTSK in COS-7 system but did reduce CTSK enzyme activity. In conclusion, the histologic and ultrastructural changes of cementum and alveolar bone might be affected by CTSK mutation via reduction of its enzyme activity (clinical trial registration: ChiCTR-TNC-10000876).

Gerodermia osteodysplastica: report on two patients and surgical correction of facial deformity.

We present four individuals with Gerodermia Osteodysplastica in a Jewish family from Morocco confirming the autosomal recessive inheritance of the disorder. Three previously unreported findings are described: a) enlarged funnel-shaped mandibular lingula; b) extension of the mandibular premolar and molar roots below the inferior dental canal, and of the second molars into the lower border of mandibular cortical bone; and c) hypercementosis of the maxillary incisors and mandibular molars surrounded by a radiolucent halo in several teeth. The facial deformity resulting from maxillary hypoplasia and mandibular prognathism was corrected by orthognathic surgery: Le Fort I maxillary osteotomy and vertical mandibular osteotomy.

Root surface characteristics of primary teeth from children with prepubertal periodontitis.

This study describes the histologic characteristics of root surfaces of primary teeth from children with prepubertal periodontitis (PP). Fifteen primary teeth from 4 children with PP, and 2 control primary teeth from 2 healthy children were examined. Light microscopy revealed normal root surfaces in the control teeth. In contrast, the PP specimens revealed bacteria inside dentin tubules or covering cementum, a cuticle, or resorbed dentin; normal, wider than normal, or hypoplastic cementum; resorption lacunae with various depths; aplastic root resorption; alternate resorption and repair; and active repair. No cementoclasts were found in the resorption lacunae. Scanning electron microscopy revealed intrabony and suprabony root areas, and a "plaque free zone" (PFZ). Colonies of filaments were evident at the cemento-enamel junction (CEJ). The suprabony root surfaces had resorption lacunae, isolated short rods, calculus, colonies of filaments, or colonies composed by an heterogeneous bacterial population. The coronal boundary of the PFZ was the border of a sheet-like structure, which included isolated rods or filaments. At the PFZ, isolated filaments and rods, and a fibril matrix were evident. The apical boundary of the PFZ consisted of bundles of soft tissue remnants or the insertion of the periodontal fibers. The intrabony surfaces were mostly covered by soft tissue, which included isolated filaments and short rods. Resorption lacunae with or without soft tissue were also evident in this area. Crystals of calcium oxalate dihydrate and erythrocytes in distinct forms were found at various root areas. The present findings are different from those previously reported for hypophosphatasia specimens.

Effect of cementum defects on radicular penetration of 30% H2O2 during intracoronal bleaching.

Bleaching pulpless teeth with 30% hydrogen peroxide has been reported to cause external cervical root resorption. It has been hypothesized that H2O2 penetrating through open dentin tubules can initiate an inflammatory reaction which could result in root resorption. Extracted human premolars were treated endodontically and bleached intracoronally using the thermocatalytic technique. The teeth were divided into three groups; one group with no cementum defects at the cementoenamel junction, one group with artificial cementum defects at the cementoenamel junction, and another group with artificial cementum defects at the middle third of the root. The radicular penetration of 30% hydrogen peroxide in the three groups was assessed directly and compared using an in vitro model. Radicular penetration of hydrogen peroxide was found in all of the groups tested. The penetration of hydrogen peroxide was significantly higher in teeth with cementum defects at the cementoenamel junction than in those without defects.

Endodontic treatment of mandibular molars with concrescence.

Endodontic treatment of a permanent mandibular first molar and a second molar presumably joined by cementum is presented. This case illustrates the difficulty in interpreting the vitality testing in such a situation. It also suggests possible irreversible pulp injury of a vital healthy tooth caused by extension of the inflammatory periapical pathosis of the adjacent tooth.

Macroscopic and microscopic analysis of the palato-gingival groove.

With the objective of correlating the anatomical aspects of the palato-gingival groove with its etiology, diagnosis, and alternative treatments, 13 permanent maxillary incisors with palato-gingival grooves were selected from a large sample and subjected to macroscopic and microscopic analysis of groove morphology. The palato-gingival groove occurred most frequently on the lingual aspect of the lateral incisor (11 of 13), and its coronal and radicular extensions were on the disto-lingual surface of the incisors (7 of 13 and 6 of 13, respectively). Deformation of the contour of the pulp cavity was noted subjacent to the groove (9 of 13), along with diminished enamel and dentin thickness (11 of 13 and 13 of 13, respectively) and an increase in cement (12 of 13). The groove was observed extending to the apical third in nine specimens, and a direct communication between the pulp and periodontium was observed in only one case. From these examinations it is concluded that the palato-gingival groove can be clinically diagnosed, preventing subsequent problems; however microscopic analysis of the affected tooth is necessary to allow precise evaluation of the groove's extension and damage to the dental structure.

Concrescence: report of a rare case.

Concrescence represents an uncommon developmental anomaly in which juxtaposed teeth are united in the cementum but not in the dentin. The incidence of concrescent teeth is reported to be highest in the posterior maxilla. The presence of concrescent teeth may influence surgical procedures as well as periodontal, endodontic and even orthodontic diagnoses and treatment. Therefore, consideration should be given to the possible occurrence, recognition, and implications of this anomaly in diagnosis and treatment planning. The purpose of this article is to report a case of concrescence between an impacted third molar and an erupted second molar that was identified postextraction.

Acro-osteolysis (Hajdu-Cheney) syndrome: report of a case with abnormal tooth structure.

The acro-osteolysis (Hajdu-Cheney) syndrome is a rare disorder of bone metabolism characterized by progressive dissolution of a number of bones. Although previous reports have detailed several dental abnormalities associated with this syndrome, this is the first report describing structural changes in the dentin and cementum of teeth.

Cementoenamel defects in an unusual location.

An unusual case involving cementoenamel defects was discussed. These defects appeared as vertical grooves at the cervical margins on the facial surfaces of the maxillary incisors. They have caused no pulpal or periodontal problems.

Histological and analytical studies of a tooth in a patient with cleidocranial dysostosis.

A histopathological and analytical study of a permanent tooth from a patient with cleidocranial dysostosis (CCD) was performed. The patient was a 47-year-old woman, who had 10 erupted permanent teeth and 2 partially erupted and 19 completely impacted teeth, including supernumerary teeth. The erupted right upper premolar was extracted and observed using a light microscope and an electron probe X-ray microanalyzer (EPMA). Findings showed enamel hypoplasia, predominantly irregular globular dentin and Tomes' granular layer, and a complete lack of cellular cementum in the ground section. The incremental von Ebner and counter Owen lines were obscure. Comparative quantitative analysis using the EPMA showed that the quantities of calcium and phosphate were lower in the enamel and dentin than those of the control sample.