Talon cusp affecting primary dentition in two siblings: a case report.

The term talon cusp refers to a rare developmental dental anomaly characterized by a cusp-like structure projecting from the cingulum area or cement-enamel junction. This condition can occur in the maxillary and mandibular arches of the primary and permanent dentitions. The purpose of this paper is to report on the presence of talon cusps in the primary dentition of two southern Chinese siblings. The 4 years and 2 months old girl had a talon cusp on her maxillary right primary central incisor, while her 2 years and 9 months old brother had bilateral talon cusps on the maxillary primary central incisors. The presence of this rare dental anomaly in two siblings has scarcely been reported in the literature and this may provide further evidence of a hereditary etiology.

Case report: idiopathic pre-eruptive coronal resorption of a maxillary permanent canine.

BACKGROUND: Coronal resorption is a coronal degeneration of enamel and dentine in which ultimately the crown is replaced by vascular connective tissue through a defect in the enamel organ of an unerupted tooth. This is also known as pre-eruptive coronal resorption. However, the aetiology of resorption remains unclear. CASE REPORT: A 13 years 7 months old Caucasian boy who attended an orthodontic consultation for anterior crossbite correction presented with idiopathic pre-eruptive coronal resorption of an erupted right maxillary permanent canine (FDI 13). Clinically, the enamel remaining on the crown was extremely thin and had a shell-like appearance. There was erythematous soft tissue within the parameters of the crown that resembled pulp tissue. From the radiographs, the irregular radiolucency area within the crown portion extended widely into the enamel and dentine. TREATMENT: Following excisional biopsy, it was decided to retain the right maxillary canine and monitor its progress. FOLLOW-UP: He has been reviewed at frequent appointments over 18-months since the time there was radiographic evidence of resorption. CONCLUSION: It is prudent to make an early diagnosis of this condition and to formulate short and long-term treatment plans, which may involve keeping the affected tooth to retain the alveolar bone height and width to allow for the option of planning for an implant.

A catalogue of anomalies and traits of the primary dentition of southern Chinese.

Variation in size, form and morphology of the teeth result in anomalies such as macrodontia, microdontia, hyperdontia, hypodontia, double tooth, taurodontism and dens in dente. While traits that may occur more commonly in certain ethnic groups may be considered to be specific to that population. The characteristics of these anomalies and traits are presented along with the prevalence figures for their occurrence in primary dentition of southern Chinese.

Feeding and oral hygiene habits of preschool children in Hong Kong and their caregivers' dental knowledge and attitudes.

OBJECTIVES: This study was designed to gather data on infant feeding habits and oral hygiene practices of Hong Kong preschool children, on the dental knowledge and attitudes of their caregivers and on the oral health status of the same group of children. DESIGN: Cross-sectional study. SAMPLE AND METHODS: Data was gathered for a total of 369 boys and 297 girls (207 1-year-olds, 269 2-year-olds and 190 3-year-olds) with a mean age of 20.19 (+/- 0.38) months. Information related to children attending six randomly selected Maternity and Child Health Centres. It was obtained by examining the children and by interviewing the attending caregivers and completing a questionnaire. Each child was given an oral examination using a torch, disposable mirror and wooden tongue spatula. RESULTS: Only 7% of the children were exclusively breast-fed. More than 98% (656/666) of infants used a nursing bottle for at least some drinks. Over 62% (411/656) had used a nursing bottle to take fluids other than water and infant formula. At bedtime, 56% (361/656) were given a nursing bottle prior to sleep and 96% (340/361) of these bottles contained formula milk. Of these children, only 37% (131/361) finished the contents of the bottle before falling asleep. Over 73% (139/190) of the children continued to use a feeding bottle after 2 years of age. Non-nutritive sucking habits were practised by 35.6% (237/666) of the children. Visible plaque, on the labial surface of at least two maxillary incisors, was found in 19.5% (120/615) of the children. Oral cleansing habits were practised for 66.2% (441/666) of the children. Toothbrushing habits were reported for 42.3% (260/615) of the dentate children, of whom 19% (49/260) had their teeth brushed twice daily. Toothpaste was used by 49.23% (128/260) of the children and 57.3% (149/260) brushed their own teeth. Caries was seen in 7.6% of the infants (47/615). Of the caregivers, 67.7% said they did not think carious primary teeth needed to be restored. Among the mothers, 12.6% (43/342) did not know the oral condition of their child. Reportedly, 82% (417/510) and 87.5% (446/510) of the mothers had not received any oral health care information during the ante- or postnatal periods. Nearly all, 97%, of the respondents said that they would like to receive more information on oral health care.

Oral-facial-digital syndrome, Type I: a case report.

Oral-facial-digital syndrome is a group of congenital anomalies, which affects the face, oral structures and digits. There are nine subtypes. OFDS type I, is x-linked dominant trait mostly affecting females. Reports of OFDS type 1 in Asians are extremely rare. This paper shows a case of OFDS type 1, in a southern Chinese girl, who in addition to most of the classic features, had fusion of the mandibular canine and lateral incisor teeth.

In vitro replication and mutagenesis of a novel reversion vector with selective DNA damage in the supF gene.

The ability to detect the most common type of UV-induced mutation, the C to T transition, at the previously characterized hotspot at position 99 of the supF gene has been demonstrated in a selectively irradiated reversion vector, pLS189(Rev). The supF region was amplified, irradiated with 500J/m(2) UVC or unirradiated, and ligated into the pLS189(Rev) plasmid. A portion of ligated product plasmid containing the irradiated fragment was sensitive to nicking by T4 endonuclease V, indicating the presence of the most common type of UV-induced damage, the pyrimidine dimer. Plasmid containing the irradiated or unirradiated supF gene was replicated completely in cellular extracts from either HeLa or XP-A cells in vitro. Plasmid containing the irradiated supF gene showed an inhibition of total replication to a level similar to those of previous studies with plasmid molecules exposed in their entirety to 40J/m(2). Replication of selectively irradiated plasmid resulted in an average reversion frequency of 0.071% in the two extracts; a 42-fold increase over the average spontaneous reversion frequency of unirradiated plasmid. The reversion frequencies were not significantly different between extracts prepared from HeLa and XP-A cells, indicating that neither the repair status of the cell lines nor the XPA protein itself affect the frequency of C to T transitions at position 99 of the supF gene in plasmid replicated in vitro. These data indicate that the plasmid pSL189(Rev), containing the selectively UV-irradiated supF gene, is a useful and sensitive tool to study mutagenesis at a specific site. This approach may be applicable to the investigation of other environmental DNA-damaging agents, by allowing the target gene to be selectively damaged while maintaining the ability of the plasmid to replicate completely. Such a system, amenable to biochemical manipulation, may be very valuable in elucidating the function of novel proteins in the process of mutagenesis.

Bonding of a self-etching primer to non-carious cervical sclerotic dentin: interfacial ultrastructure and microtensile bond strength evaluation.

PURPOSE: The objectives of this study were 1) to examine the ultrastructural features of the resin-sclerotic dentin interface following the application of Clearfil Liner Bond II sigma to natural cervical wedge-shaped lesions, and 2) to evaluate the regional tensile bond strength of this self-etching primer at different locations on natural and artificially-created cervical lesions. MATERIALS AND METHODS: Deep cervical natural lesions were bonded using the self-etching primer. Micromorphology of the bonded interface at different locations within the lesions were examined using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and scanning transmission electron microscopy/energy dispersive x-ray analysis (STEM/EDX). Ultrastructural features were further compared with the use of the same self-etching primer on artificial lesions created in sound cervical dentin. A nontrimming technique was used to evaluate the regional tensile bond strength from the occlusal, gingival, and the deepest central part of both natural and artificial cervical lesions. Beams with a mean area of 0.46 +/- 0.03 mm2 were prepared and were pulled to failure using a Bencor Multi-T testing device attached to an Instron universal tester. Bond strength results were evaluated using a two-way ANOVA design. RESULTS: A hypermineralized layer devoid of intact, banded collagen was invariably present on the surface of the natural lesions. Depending upon its thickness at different locations of the lesion, the action of a self-etching primer may be limited to this surface layer alone, producing a hybridized hypermineralized surface layer. Penetration of the self-etching primer into the underlying sclerotic dentin produced a hybridized complex containing a hybridized hypermineralized surface layer as well as a subsurface layer of hybridized intertubular dentin. Bacterial colonization of the lesion surface resulted in the formation of an additional zone of hybridized intermicrobial matrix over the surface of the lesions. Dentinal tubules remained blocked with sclerotic casts, and resin tags were rarely observed. Regional tensile bond strength results showed that the overall bond strength to natural sclerotic dentin was about 20% lower than sound cervical dentin, but was independent of the different locations within the lesions from which bond strength was evaluated. CONCLUSION: There were four factors that may have influenced the overall decrease in bond strength in natural cervical sclerotic lesions: a) the presence of a hybridized intermicrobial matrix together with entrapped bacteria may have weakened the bonds, b) inability of a self-etching primer to etch through a thick, hypermineralized surface layer, c) presence of a layer of possibly remineralized, denatured collagen at the base of the hypermineralized surface layer, and d) retention of acid-resistant sclerotic casts that obliterate the tubular lumina and prevent effective resin tag formation.

Oral rehabilitation of a hypohidrotic ectodermal dysplasia patient: a 6-year follow-up.

This case report describes the oral rehabilitation of a female child with hypohidrotic ectodermal dysplasia over a 6-year time period. It demonstrates the need for periodic modification and replacement of a prosthesis, an orthodontic appliance, and a gingivoplasty. Although the initial treatment plan was considered to be a compromise due to limited cooperation, an improvement was observed in the patient's social behavior as a consequence of her dental treatment. The effects of unavoidable changes in the dental team over 6 years are also discussed.

A catalogue of anomalies and traits of the permanent dentition of southern Chinese.

Variations in size, form and morphology of the teeth can result in anomalies such as macrodontia, microdontia, hyperdontia, hypodontia, double tooth, dens evaginatus, dens invaginatus, and talon cusp. A trait may occur more commonly in certain ethnic groups. Among these traits are shovel-shaped incisors, lingual tubercle, Carabelli's trait and protostylid of the molars. Because people are traveling more frequently than ever before, and there are many migrants in different parts of the world, it is increasingly important for dental professionals to be aware of the characteristics and prevalence of the anomalies and traits that occur in the different ethnic groups, so as to be able to make valid clinical judgments and to provide the appropriate treatment. The characteristics of these anomalies and traits are presented along with the prevalence figures in the southern Chinese.

Ectodermal dysplasia: a review and case report.

Ectodermal dysplasia is a hereditary disease characterized by a congenital dysplasia of one or more ectodermal structures and their accessory appendages. Common manifestations include defective hair follicles and eyebrows, frontal bossing with prominent supraorbital ridges, nasal bridge depression, and protuberant lips. Intraorally, common findings are anodontia or hypodontia, conical teeth, and, consequently, generalized spacing. The patient may suffer from dry skin, hyperthermia, and unexplained high fever as a result of the deficiency of sweat glands. The present review focuses on the clinical manifestations, classifications, and diagnosis of ectodermal dysplasia. A 6-year-old girl, described in the case report, exhibited many of the manifestations of ectodermal dysplasia as well as behavioral problems and a severe gag reflex. The treatment to improve her appearance and oral function included a removable prosthesis, acid-etch-retained indirect resin composite veneers, and a fixed partial denture.

The ectrodactyly-ectodermal dysplasia-clefting syndrome: a literature review and case report.

Ectrodactyly, atypical anhidrotic ectodermal dysplasia, and cleft lip and palate are the principal manifestations of ectrodactyly-ectodermal dysplasia-clefting syndrome. Intraorally, the common manifestations of the syndrome are hypodontia, enamel hypoplasia, and generalized microdontia. In addition, the patient may suffer from xerostomia and have a deeply fissured tongue. The oral mucosa appears, in some patients, to have an increased susceptibility to candidiasis. This case report describes a patient who exhibits many of the manifestations of the syndrome and explains ways in which many of the anomalies of the dentition can be esthetically and functionally corrected.

Radiographic features of the bones of the hand and wrist in achondroplasia: report of case.

Achondroplasia is a well-established and documented medical condition. Most of the diagnostic features are discernible from a clinical examination, which are complemented by radiographic findings of the bones of the skeleton. The findings from the hand-and-wrist radiograph of an affected Southern Chinese male infant, age thirty-nine-months, are reported. The findings from this case indicated an infrequently reported abnormality in the development of the hand in achondroplasia.

Development of a tooth germ within an autogenous clavicular graft.

The left side of the mandible distal to the second primary molar of a 3 years old Southern Chinese boy was resected as a result of osteomyelitis. A diaphyseal clavicular graft pedicled on the sternomastoid muscle was selected for the reconstruction of the mandible. By the age of 6 years, the mandible although stunted in size did exhibit appropriate remodelling. In addition a tooth germ in the region of the second permanent molar was found developing in the autogenous bone graft of the mandible.

An intranasal tooth in a patient with a cleft lip and palate: report of case.

Teeth located in the nasal cavity are a rare phenomenon of uncertain cause. A case is presented of such an anomaly found in a patient with a repaired cleft lip and palate. A review of the literature with a discussion of the clinical features, diagnosis, treatment, and etiology is also included.

Natal teeth and steatocystoma multiplex: a newly recognized syndrome.

A Chinese family is reported in which five generations have exhibited natal teeth and generalized multiple steatocystomas. This autosomal dominant condition is not similar to the two reported types of pachyonychia congenita, because nail lesions, palmoplantar keratosis and hyperhidrosis, follicular keratosis, and oral leukokeratosis were not observed. Therefore, it is suggested that this family exhibits a newly recognized syndrome.

Oral and craniofacial morphology of a patient with Larsen syndrome.

A case is reported of a 15 years old Chinese female with Larsen syndrome exhibiting many characteristic facial and skeletal features plus hitherto unreported orofacial anomalies including delayed dental development; hypodontia affecting all the permanent canines, second and third molars, maxillary lateral incisors and second premolars; morphological anomalies of the maxillary first premolars and molars; a class 3 skeletal pattern and reduced upper facial height. Cephalometric radiographs showed the skull bones to have an appearance similar to that of osteopetrosis.