A longitudinal case-control study of caries development from birth to 36 months.

BACKGROUND/AIMS: The aim of this longitudinal case-control study was to investigate variables associated with caries development from birth to 36 months. METHODS: Children (n = 1,017) who were followed up every 6 months from birth to 36 months were grouped into those that developed caries by age 30 and 36 months, respectively, and compared with children without caries. RESULTS: By 30 months (n = 608) there were 24 children (4%) who had caries and an additional 23 developed first caries at 36 months (n = 552), giving a total prevalence of 47 children with caries (9%) at 36 months. Children who showed caries by 30 months were more likely to be mutans streptococci (MS) colonised by 18 months (p = 0.001) compared to those who developed caries at 36 months, and showed the following variables: MS counts of >10(5) CFU/ml at 12 months (p = 0.005), missing enamel (p = 0.001), sugar in pacifier at 18 months (p = 0.02), child sleeping next to mother at 6, 18 and 24 months (p = 0.001 to p = 0.02), and exposure to household cigarette smoke at 24 months (p = 0.02). Caries at 36 months was associated with pregnancy problems (p = 0.024), mother having dental cavitations (p = 0.001) and MS presence at 36 months (adjusted odds ratio, AOR = 0.1, p = 0.01 for counts <10(5) CFU/ml). Caries at both 30 and 36 months was associated with MS presence at 18 months (AOR = 6.3, p = 0.005 and AOR = 4.9, p = 0.01). CONCLUSIONS: Children who developed caries by 30 months are colonised by MS at younger ages and with higher MS counts compared with children who develop caries at 36 months.

A longitudinal study comparing mutans streptococci and lactobacilli colonisation in dentate children aged 6 to 24 months.

This longitudinal study aimed to investigate variables associated with colonisation of mutans streptococci (MS) compared with lactobacilli (LB) colonisation in a cohort of children (n = 214) from the time of first tooth eruption at approximately 6 months until 24 months of age. Repeated plaque and salivary samples were collected from the same infants at 6, 12, 18 and 24 months and assayed for MS and LB using a microbiological culture kit. Children having both MS and LB increased from 4% at 6 months to 13% at 12 and 18 months to 20% at 24 months (p = 0.004). LB presence at 6 months was correlated with MS presence at 12, 18 and 24 months (r = 0.21 to r = 0.46, p = 0.02), while MS presence at 6 months correlated with LB presence at all other times (r = 0.19 to r = 0.31, p = 0.03). At 6 and 12 months, the key variables for MS colonisation included unrestored dental cavities in the mother (p = 0.03), mother not persisting with toothbrushing (p = 0.001) and bottle taken to bed at night (p = 0.033), while the only significant variable for LB colonisation was natural birth (p = 0.01). At 24 months, the significant variables for MS colonisation were condiments added to pacifier (p = 0.022) and child being uncooperative for toothbrushing (p = 0.025), while the significant variables for LB colonisation were pregnancy problems (p = 0.028) and child being uncooperative for toothbrushing (p = 0.013). The ages 6-12 months thus represent a time period when key variables may be controlled to reduce MS and LB colonisation.

Spatial and temporal coordination of expression of immune response genes during Pseudomonas infection of horseshoe crab, Carcinoscorpius rotundicauda.

Knowledge on how genes are turned on/off during infection and immunity is lacking. Here, we report the co-regulation of diverse clusters of functionally related immune response genes in a horseshoe crab, Carcinoscorpius rotundicauda. Expressed sequence tag (EST) clusters for frontline immune defense, cell signalling, apoptosis and stress response genes were expressed or repressed spatio-temporally during the acute phase of Pseudomonas infection. An infection time course monitored by virtual Northern evaluation indicates upregulation of genes in blood cells (amebocytes) at 3-h postinfection, whereas most of the hepatopancreas genes remained down regulated over 72 h of infection. Thus, the two tissues orchestrate a coordinated and timely response to infection. The hepatopancreas probably immuno-modulates the expression of other genes and serves as a reservoir for later response, if/when chronic infection ensues. On the other hand, being the first to encounter pathogens, we reasoned that amebocytes would respond acutely to infection. Besides acute transactivation of the immune genes, the amebocytes maintained morphological integrity, indicating their ability to synthesise and store/secrete the immune proteins and effectors to sustain the frontline innate immune defense, while simultaneously elicit complement-mediated phagocytosis of the invading pathogen. Our results show that the immune response against Pseudomonas infection is spatially and temporally coordinated.

Diagnosis and management of unusual dental abscesses in children.

Although the majority of dental abscesses in children originate from dental caries or trauma, a few are associated with unusual conditions which challenge diagnosis and management. Recent research findings have shed light on these unusual entities and greatly improved understanding of their clinical implications. These conditions include developmental abnormalities such as dens invaginatus in which there is an invagination of dental tissues into the pulp chamber and dens evaginatus in which a tubercle containing pulp is found on the external surface of a tooth crown. In addition, inherited conditions which show abnormal dentine such as dentine dysplasia, dentinogenesis imperfecta, and osteogenesis imperfecta predispose the dentition to abscess formation. Furthermore, 'spontaneous' dental abscesses are frequently encountered in familial hypophosphataemia, also known as vitamin D-resistant rickets, in which there is hypomineralization of dentine and enlargement of the pulp. In addition to developmental conditions, there are also acquired conditions which may cause unusual dental abscesses. These include pre-eruptive intracoronal resorption which was previously known as 'pre-eruptive caries' or the 'fluoride bomb'. In addition, some undiagnosed infections associated with developing teeth are now thought to be the mandibular infected buccal cysts which originate from infection of the developing dental follicles. In the present paper, these relatively unknown entities which cause unusual abscesses in children are reviewed with the aim of updating the general practitioner in their diagnosis and management.

Comparison of five selective media for the growth and enumeration of Streptococcus mutans.

BACKGROUND: Although a few growth media are available for selective isolation of the cariogenic bacteria, Streptococcus mutans (S. mutans), it is still unclear as to which is the most efficacious. This study compared the selectivity and sensitivity of five different media for growing a laboratory strain of S. mutans (NCTC 10449), and for enumerating S. mutans from teeth of a group of young children, aged 2-10 years. METHODS: The media tested in this study were mitis salivarius with bacitracin (MSB), mitis salivariuskanamycin-bacitracin (MSKB), glucose-sucrose-tellurite-bacitracin (GSTB), trypticase soy-sucrose-bacitracin (TYS20B) and tryptone-yeast-cysteine-sucrose-bacitracin (TYCSB) agars. These were prepared according to the respective manufacturer's instructions. RESULTS: The results showed that at concentrations of bacteria 1 x 10(3) to 1 x 10(10)/mL, the recovery of the laboratory S. mutans strain was highest in TYCSB agar, followed by in descending order by TYS20B, MSB, GSTB, and MSKB (p<0.01). Similar results were obtained using dental plaque samples collected from swabs of the teeth of a group of children. In the clinical samples, TYCSB again showed the highest recovery rates of S. mutans compared to the other four media. Results were reproduced at dilutions of the samples at 1:20 x 10(6) to 1:2 x 10(6), and S. mutans concentrations of 1.6 to 7.7 Log 10 CFU/mL. In addition, there were highest ratios of mutans to non-mutans bacteria in TYCSB compared to the other media, suggesting high selectivity of this media for mutans species. CONCLUSION: The results of our study suggest that TYCSB is the most sensitive and selective media for culture of S. mutans for laboratory and clinical studies.

Association of Streptococcus mutans infection and oral developmental nodules in pre-dentate infants.

Since dental caries may present soon after tooth eruption, we hypothesized that colonization of Streptococcus mutans can occur in the predentate stages. In this study, we examined S. mutans colonization and its association with oral developmental nodules (Bohn's nodules) in 60 pre-term and 128 full-term, three-month-old infants. Overall, S. mutans was cultured from 30% (56/188) of the infants, and oral developmental nodules were noted in 55% (103/188). Compared with the pre-term, full-term infants showed a higher prevalence of S. mutans (34% vs. 20%, p < 0.02) as well as developmental nodules (61% vs. 42%, p < 0.05). In both groups, S. mutans was positively associated with numbers of developmental nodules in a dose-response relationship (p < 0.001), and with maternal salivary levels of the bacteria (p = 0.03). The permanence of S. mutans infection was confirmed by repeat saliva sampling at 6 months of age. Our results thus showed that many infants have already acquired S. mutans at 3 months of age, prior to tooth eruption.

Identification of cathepsin C mutations in ethnically diverse papillon-Lefèvre syndrome patients.

INTRODUCTION: Papillon-Lefèvre syndrome (PLS) is an autosomal recessive disorder characterised by palmoplantar keratoderma and severe, early onset periodontitis, which results from deficiency of cathepsin C activity secondary to mutations in the cathepsin C gene. To date, 13 different cathepsin C mutations have been reported in PLS patients, all of which are homozygous for a given mutation, reflecting consanguinity. AIM: To evaluate the generality of cathepsin C mutations in PLS, we studied an ethnically diverse group of 20 unrelated families. METHODS: Mutations were identified by direct automated sequencing of genomic DNA amplified for exonic regions and associated splice site junctions of the cathepsin C gene. Long range PCR was performed to determine the genomic structure of the cathepsin C gene. RESULTS: The cathepsin C gene spans over 46 kb, with six introns ranging in size from 1.6 to 22.4 kb. Eleven novel mutations and four previously reported mutations were identified in affected subjects from 14 families. Missense mutations were most common (9/15), followed by nonsense mutations (3/15), insertions (2/15), and deletions (1/15). Among these 14 probands, two were compound heterozygotes. Affected subjects with transgressions of the dermal lesions onto the knees or elbows or both had mutations in both the pro- and mature regions of the enzyme, although most were in the mature region. CONCLUSION: Mutations in the mature region of cathepsin C were more likely to be associated with the transgressions of the dermatological lesions, although the results were not statistically significant. A comprehensive list of all cathepsin C mutations described to date, representing 25 mutations from 32 families with PLS and related conditions, is also presented.

Prevalence of pre-eruptive intracoronal dentin defects from panoramic radiographs.

PURPOSE: This investigation stemmed from preliminary clinical observations from a school dental clinic, which suggested that a proportion of clinically undetected, radiolucent lesions on radiographs may originate as pre-eruptive intracoronal dentin defects. This study investigated the prevalence of such defects in orthopantomograms from a group of children and young adults. METHODS: A total of 1281 orthopantomograms with 11,767 unerupted permanent teeth were examined. RESULTS: The prevalence of intracoronal dentin defects was 3% by subjects, and 0.5% by teeth; the highest prevalence being noted in the maxillary and mandibular first permanent molars. Most of the lesions occurred singly, and nearly half had extended to greater than two-thirds the width of dentin thickness. Ectopic positioning was significantly associated with this lesion. CONCLUSIONS: Pre-eruptive intracoronal dentin defects occur at a significant prevalence rate. Increased awareness of this entity may improve diagnosis and allow early treatment.

Clinical diagnosis of enamel defects: pitfalls and practical guidelines.

Changes in enamel during its development are permanently recorded, and commonly present as either demarcated opacity, diffuse opacity, or enamel hypoplasia. Developmental enamel defects may provide clues regarding their aetiology, and this may have application in clinical dentistry, dental epidemiology and anthropology. However, the usefulness of these applications may be hampered by many pitfalls encountered in the detection and diagnosis of developmental enamel defects. The defects may be masked by saliva, dental plaque, and incorrect lighting. In addition, confounding effects of post-eruptive changes such as dental caries, attrition, and traumatic loss of tooth structure may impair the detection of developmental enamel defects. The non-specificity of appearance of enamel defects may make aetiologic diagnosis of enamel hypoplasia difficult. Furthermore, difficulty is often encountered in the relative timing of events in enamel hypoplasia, due to limited data on the chronology of development of the human dentition. In this review, pitfalls in the clinical assessment of enamel defects are discussed, and guidelines to overcome some of these difficulties are presented.

Effects of preterm birth on oral growth and development.

Preterm and low birthweight children comprise approximately 6 per cent of all live births. They are prone to many serious medical problems during the neonatal period which may affect the development of oral tissues. The present paper reviews the results of this author's own decade of research into the oral development of preterm children in the light of current understanding of the field. Studies have shown a high prevalence of generalized enamel hypoplasia in the primary dentition of around 40-70 per cent in preterm children which is likely to be associated with low bone mineral stores. The clinical significance of enamel defects is poor aesthetics, and predisposition of the lesions to dental caries. Other dental defects observed in preterm children are localized enamel hypoplasia, crown dilacerations, and palatal distortions which are usually associated with traumatic laryngoscopy and prolonged endotracheal intubation. Furthermore, recent studies have demonstrated that the rate of dental development, and dental eruption may be affected by preterm birth. Children with the lowest birthweight and shortest gestational ages have the lowest rates of dental development, particularly before six years of age. The results of these clinical studies may have significant implications in the dental management of preterm children.

Effect of familial hypophosphatemic rickets on dental development: a controlled, longitudinal study.

Familial or X-linked hypophosphatemic rickets (XLHR) is the most common type of rickets in developed countries today. While the dental manifestations of rickets are well reported, there is little information regarding its relationship to dental development and other dental anomalies. This investigation studied the rate of dental development and associated dental anomalies in 19 XLHR subjects compared with 38 race-, age-, and sex-matched control children. The results showed that in both XLHR and control children, no significant differences existed in dental age compared with the respective chronological age, indicating that rickets did not affect the rate of dental development. Longitudinal growth curves of seven XLHR and matched control children substantiated that relationships of dental to chronological ages were comparable in both groups. Male XLHR subjects showed significantly increased tendency for dental taurodontism with mean Crown-Body (CB):Root (R) ratio of 1.1 compared with 1.0 in females and 0.8 in controls (P < 0.02). Male XLHR children also showed significantly increased prevalence (50%) of ectopic permanent canines compared with control children (8%, P < 0.01).

Dental development and molar root length in children with cleidocranial dysplasia.

Cleidocranial dysplasia (CD) is an autosomal dominant skeletal disorder with characteristic dental findings of numerous supernumerary teeth and noneruption of permanent teeth. This investigation compared the dental development and root lengths of the mandibular first permanent molar in 11 CD patients with those of 22 healthy, normal children matched for race, age and sex. The results showed that children with CD experienced a delay in dental development of approximately 3 years compared with normal children (P < 0.05). In addition, the root lengths of the mandibular first permanent molar were significantly longer than those of the comparison children (17.8 +/- 1.6 mm vs 13.6 +/- 1.2 mm (P < 0.001). This study thus revealed two significant clinical features of CD: 1) severe delay in dental development, and 2) excessive root lengths of mandibular permanent first molars. These features may be important in the pathogenesis of delayed dental eruption observed in this disorder.

Dental development in amelogenesis imperfecta: a controlled study.

The present investigation studied dental development in 23 subjects with amelogenesis imperfecta (AI), aged 4.2 to 15.6 years, compared with 46 race-, age-, and sex-matched, healthy, normal controls. The dental ages of the children were assessed from panoramic radiographs using previously established methods. Their chronologic ages at the time of radiographic examination were compared with their dental ages. The results showed that all subjects with AI showed a significant acceleration of dental age of approximately 1.13 +/- 0.78 years compared with control children (P < 0.001). All children were consistently affected regardless of the AI variant. Furthermore, the study found a six-fold increase (26.1 vs. 4.3%) in tendency of AI patients to show impaction of the permanent teeth and associated anomalies such as follicular cysts. These results may be important in planning orthodontic treatment in AI patients, and indicate that they should have early screening to detect these abnormalities.

Spectrum of dentin dysplasia in a family: case report and literature review.

The dentin dysplasias (DD), which may be classified as type 1 (DD1) or type 2 (DD2), form a group of rare, inherited dentin abnormalities that are clinically distinct from dentinogenesis imperfecta. Studies of affected families may help to distinguish different types of DD and provide further insight into their etiology and clinical management. This report describes a family that showed characteristic dental features of DD1, including clinically normal crowns in both primary and permanent dentitions, and mobile teeth that may be associated with premature exfoliation. Radiographic features included calcification of the pulp with crescent-shaped, radiolucent pulp remnants, short, tapering, taurodontic roots, and many periapical pathoses that may be cysts or granulomas. A spectrum of dentin dysplasia was noted within the family. Strategies to prevent pulp and periapical infections and early exfoliation of the teeth include meticulous oral hygiene and effective caries-preventive measures.

Root agenesis associated with chronic infection and traumatic curettage of the maxillary sinus.

A healthy 13-year-old female was found to have no roots on the maxillary left second premolar and permanent first and second molars. Her history included chronic sinus infections treated with maxillary sinus curettage at approximately 4 years of age. The infection, or more likely the trauma associated with the surgery, may have caused agenesis of the roots. Other causes of rootless teeth such as odontodysplasia, dentin dysplasia, trauma, infection, radiation therapy, and neoplasia were excluded from her history and clinical and radiographic findings. This report suggests that damage to the developing dentition may be a serious complication of maxillary sinus surgery or chronic infection.

Nicotine-induced release of elastase and eicosanoids by human neutrophils.

We examined the direct effects of nicotine on a variety of neutrophil functions at concentrations achievable in lung and oral tissues from cigarette smoking. The results show dose-dependent suppression of chemotaxis and phagocytosis, and enhancement of degranulation and eicosanoid generation, but not superoxide production. Cell viability was not affected by the concentrations of nicotine used in these experiments, as shown by trypan blue dye exclusion and MTT assays. These results implicate nicotine as the ingredient in cigarette smoke responsible for inflammatory damage to lungs and oral tissues observed in cigarette smokers.

Effect of berbamine on blood and bone-marrow stem cells of cyclophosphamide-treated mice.

The bisbenzylisoquinoline alkaloid berbamine has been used in China and Japan for the therapy of leukopaenic complications of cancer. Mice treated with non-toxic doses showed significant enhancement of neutrophil and lymphocyte counts in the circulation, but a decrease in the numbers of bone marrow stem cells in a dose-dependent manner after two weeks. Similar findings were observed in cyclophosphamide-treated mice. These results indicate that berbamine acts by stimulating the maturation and release of leukocyte progenitors, and may have value in leukopaenic patients.

Trichodentoosseous (TDO) syndrome: case report and literature review.

Trichodentoosseous (TDO) syndrome is an autosomal dominant condition characterized by dysplastic nails, curly hair, bone sclerosis of the long bones and calvarium, taurodontism, and enamel hypoplasia that occurs with hypomaturation/hypocalcification defects. To date, nine previous case reports of TDO in the dental literature have shown that while taurodontism and enamel defects are consistently present in TDO, the changes in the nails, hair, and bones may be variably expressed and occasionally not noted. Because of this, a few previous cases of TDO syndrome had been diagnosed simply as amelogenesis imperfecta. This case report highlights the typical clinical findings, diagnostic problems, and the clues to diagnosing this interesting condition. Clinical management of TDO is centered on preventing dental abscesses with stainless steel crowns and improving appearance with esthetic restorations.

Taurodontism of the mandibular first permanent molar distinguishes between the tricho-dento-osseous (TDO) syndrome and amelogenesis imperfecta.

The diagnosis of tricho-dento-osseous (TDO) syndrome is often confused with that of a variant of amelogenesis imperfecta (AI) which shows similar dental features of hypomaturation-hypoplastic enamel defects and putative taurodontism. In this controlled study, an objective, biometric measurement technique was used to determine the prevalence and severity of taurodontism of the mandibular first permanent molar in 23 patients with AI and one patient with TDO syndrome compared with age- and sex-matched controls. The published radiographs of previous cases of TDO and hypomaturation-hypoplastic AI were also reviewed with regard to the presence and severity of taurodontism. The results indicate that in all cases of TDO, taurodontism of the molars including mandibular first permanent molars was consistently present and in a severe form. By contrast, the taurodontic defects present in all cases of AI, including the hypomaturation-hypoplastic variant were not significantly different from matched, healthy controls. Of significance is the fact that in all the AI cases, none of the taurodontic defects were present on the mandibular first permanent molars. The results indicate that true taurodontism as indicated by a change in the mandibular first permanent molars occurs only in the TDO syndrome. This feature may be used to differentiate clearly between TDO and AI.