Gene expression during palate fusion in vivo and in vitro.

UNLABELLED: Failure of secondary palate fusion during embryogenesis is a cause of cleft palate. Disappearance of the medial epithelial seam (MES) is required to allow merging of the mesenchyme from both palatal shelves. This involves complex changes of the medial edge epithelial (MEE) cells and surrounding structures that are controlled by several genes whose spatio-temporal expression is tightly regulated. We have carried out morphological analyses and used a semi-quantitative RT-PCR technique to evaluate whether morphological changes and modulation in the expression of putative key genes, such as twist, snail, and E-cadherin, during the fusion process in palate organ culture parallel those observed in vivo, and show that this is indeed the case. We also show, using the organotypic model of palate fusion, that the down-regulation of the transcription factor snail that occurs with the progression of palate development is not dependent on fusion of the palatal shelves. ABBREVIATIONS: dsg1, desmoglein1; EMT, epithelial-mesenchymal transition; MEE, medial edge epithelium; MES, medial epithelial seam; RT-PCR, reverse-transcriptase polymerase chain-reaction.

Dental health indices and caries-related microflora in children with severe haemophilia.

The purpose of this work was to investigate the prevalence of dental caries, bacterial dental plaque, gingivitis, enamel defects and caries- related microflora in children with severe haemophilia. Thirty-eight children with severe haemophilia (factor VIII and IX < 2 U dL(-1)) were recruited from Great Ormond Street Hospital for Children and matched for age, gender and ethnicity with healthy control children from the Eastman Dental Institute. Indices were recorded for decayed, missing, and filled teeth and surfaces in both the deciduous dentition (dmfs/dmft) and the permanent dentition (DMFS/DMFT). The plaque and gingivitis scores and developmental enamel defects were also recorded. The caries-related microflora was sampled and cultured for Streptococcus mutans, and Lactobacilli and Candida species. A significantly greater proportion of children with severe haemophilia were caries-free compared with the controls (36.7% vs. 13.3%; P=0.04). Both the DMFS and DMFT were significantly greater in the controls (3.6 and 2.8, respectively) compared with the haemophilia group, (0.8 and 0.7; P=0.007 and P=0.04). The plaque score for the permanent dentition only was significantly greater for the control children (24.2) compared with the haemophilia group, (10.2; P=0.04). The mean number of colony forming units of S. mutans was significantly greater in the control group compared with the haemophilia group (P=0.05). We conclude that children with severe haemophilia have a significantly lower prevalence of dental caries compared with matched, healthy controls.

Dental procedures in children with severe congenital heart disease: a theoretical analysis of prophylaxis and non-prophylaxis procedures.

OBJECTIVE: To estimate the cumulative exposure to bacteraemia from dental procedures currently recommended for antibiotic prophylaxis and compare this with cumulative exposure from dental procedures not recommended for prophylaxis. DESIGN: Retrospective analysis. SETTING: University and teaching hospital maxillofacial and dental department. PATIENTS: 136 children with severe congenital cardiac disease attending for dental treatment between 1993 and 1998 and for whom full records were available. Each dental procedure was tallied. MAIN OUTCOME MEASURES: Cumulative exposure per annum to "non-prophylaxis procedures"; cumulative exposure per annum to "prophylaxis procedures". RESULTS: Cumulative exposure to bacteraemia from prophylaxis procedures was not significantly greater than from non-prophylaxis procedures. CONCLUSIONS: The data raise important questions about the appropriateness of current guidelines for antibiotic prophylaxis of bacterial endocarditis.

Dental maturity in children with dystrophic epidermolysis bullosa.

PURPOSE: This study was performed to compare Dental Age (DA) of children with Dystrophic Epidermolysis Bullosa recessiva (DEBr) with the DA of healthy children. METHODS: Orthopantomographs (OPG's) of children with DEBr were compared with those of healthy children. Dental maturity was estimated using Dermirjian's method. A total of 48 pairs of OPG's were compared. RESULTS: There was a considerable range of variation in the difference between the chronological age and the dental age of both groups. This varied from minus 2 years 8 months to plus 3 years for the control children and minus 3 years 1 month to plus 3 years 4 months for the DEBr children. Despite this wider range the average DA of children with DEBr was statistically significantly delayed by 2 years 3 months. CONCLUSIONS: The delay in dental developmental of children with DEBr may have an impact on the clinical management of these children.

Dental health indices and caries associated microflora in children with unilateral cleft lip and palate.

OBJECTIVE: To investigate the dental health and caries related microflora of children with unilateral cleft lip and palate. STUDY GROUP: Sixty children with unilateral cleft lip and palate and matched controls. OUTCOME MEASURES: The decayed, missing, and filled teeth and surfaces in both the deciduous and permanent dentitions. The presence of developmental defects and plaque and gingivitis scores were also recorded. Plaque was collected from 25 of the children and their matched controls from three different sites, which were (1) the first approximal site distal to the cleft, (2) a contralateral anterior site, and (3) a remote site. It was cultured for Streptococcus mutans and lactobacilli. Plaque was collected from two sites in the matched controls. RESULTS: There was no significant difference in the caries, plaque, and gingivitis scores between the children with cleft palate and the controls. A greater number of enamel opacities were recorded in the control group, and there was a higher prevalence of enamel discoloration in the children with cleft lip and palate. There was no significant difference in the proportion of S. mutans or lactobacilli at the cleft site, compared with the unaffected site in the study group, although there was an anterior-posterior gradient in the proportion of S. mutans. There was no significant association between the stagnation area at the cleft site and the bacteria associated with dental caries.

A preliminary investigation of dental disease in children with HIV infection.

OBJECTIVE: To establish the levels of dental caries and gingivitis in a group of HIV-positive children. STUDY GROUP: The study group comprised 35 children with the Human Immunodeficiency Virus attending The Great Ormond Street Hospital For Children. OUTCOME MEASURES: Outcome measures included the number of decayed, missing and filled teeth and surfaces in both the primary and permanent dentitions; plaque and gingivitis scores. RESULTS: The children included 18 boys and 17 girls. They were aged from 6 months to 18 years, with 17 aged 5 years or less and 15 aged 6 years or older. Twenty-four of the 35 children had some caries experience. The mean DMFT was 4.4 and for those with permanent teeth the mean DMFT was 0.7. Mean plaque and gingivitis scores were 16.7 and 5.1 for plaque and gingivitis adjacent to primary teeth and 8.0 and 5.7 for that related to permanent teeth. CONCLUSIONS: There is a significant treatment need for children with HIV.

Dental problems associated with hypophosphataemic vitamin D resistant rickets.

OBJECTIVE: To review a series of cases of hypophosphataemic vitamin D resistant rickets. SUBJECTS INCLUDED: Seventeen cases, aged between 2 years 1 month and 15 years 9 months at first referral, and with an established diagnosis of vitamin D resistant rickets from twelve families were included in the review. Information was drawn from patient records for follow-up periods between 9 months and 20 years 4 months. SETTING: All subjects had been referred to the Eastman Dental Hospital between 1973 and 1997. FINDINGS: Abscessed non-carious primary and/or permanent teeth were a presenting feature in eleven of the seventeen cases. Although attrition and exposure of the abnormally formed dentine accounted for the route of infection in primary teeth, the route for microbial invasion of pulpal tissues in permanent teeth remained unexplained in a number of patients. The possible part played by infractures of the enamel as a portal of entry for infection is discussed. Enamel defects were observed in only six patients, in three of whom these changes were limited to the primary dentition. Taurodontism of permanent molar teeth was confirmed as a feature of the condition in the more severely affected male subjects.

Severe Infra-occlusion and failed eruption of deciduous molars associated with eruptive and developmental disturbances in the permanent dentition: a report of 28 selected cases.

Retrospective analysis of 28 children suffering from severe infra-occlusion and/or primary failure of eruption of deciduous molars revealed an association with eruptive and developmental disturbances in the permanent dentition, including ectopically placed teeth and aplasia of teeth. Taurodont permanent molars were evident in 19 of the 28 selected cases which suggests a possible developmental relationship between these factors. Problems in relation to treatment of these cases are discussed.

Use of proprietary agents to relieve recurrent aphthous stomatitis.

AIM: To examine the subjective efficacy of proprietary agents for aphthous stomatitis. DESIGN: A simple open study. SETTING: Hospital out-patients in the UK in 1993. SUBJECTS: 50 consecutive patients with aphthae. OUTCOME: Patients assessed agent efficacy as very effective, possibly effective or not effective at relieving symptoms. RESULTS: 38 of 54 available agents were used. Difflam Oral Rinse (benzydamine hydrochloride) appeared to give most control of pain. Overall, Corsodyl mouthwash (chlorhexidine gluconate) gave most beneficial effect. CONCLUSIONS: Difflam and Corsodyl appear to give some symptomatic relief to aphthous victims.

In vitro investigation of fluoride ion release from four resin-modified glass polyalkenoate cements.

Conventional glass ionomer cements are known to release fluoride ions to the surroundings. Recently, resin-modified glass ionomer cements have been produced. These have differing chemical formulations and this may affect their ability to release fluoride ions. The study evaluates both the fluoride release and compressive strength of one conventional and four resin-modified glass ionomer cements with respect to time. The results showed that the formulation of the resin-modified materials influenced the fluoride release. One resin-modified glass ionomer (PhotacFil) released more fluoride than all other materials, while Vitremer, Fuji II LC and Chemfil Superior release similar amounts. Variglass had a very much smaller elution of fluoride ions. This suggests that there is considerable variation in fluoride release between materials of similar generic origin. The compressive strength of these materials was not affected with time.

Absence of salivary glands in children with rampant dental caries: report of seven cases.

Seven cases of absence of two or more salivary glands in children are presented. In six of the cases the condition was congenital and in one it was the result of surgery to the submandibular ducts. The patients had been referred for treatment of rampant dental caries and were reviewed for periods ranging from 6 months to 15 years 9 months. The diagnosis of absence of salivary glands was based on careful inspection and palpation of the duct and duct orifice of each gland. One patient had dry lips and three had dry mouths, but none complained of excessive thirst or difficulty with mastication or swallowing. All the patients had very poor oral hygiene and rampant dental caries. The presence of carious lesions in mandibular incisors, particularly when their severity exceeds those present elsewhere in the mouth, should alert the clinician to the possibility that salivary glands may be absent.