Incompetent lip seal and nail biting as risk factors for malocclusion in Japanese preschool children aged 3-6 years.

BACKGROUND: Malocclusion is a multifactorial condition associated with genetic and environmental factors. The purpose of this study was to investigate the prevalence of occlusal traits, oral habits, and nose and throat conditions by age and to assess the association between malocclusion and its environmental factors in Japanese preschool children. METHODS: A total of 503 Japanese children (258 boys and 245 girls aged 3-6 years) were recruited. Occlusal traits were assessed visually to record sagittal, vertical, and transverse malocclusion, and space discrepancies. Lip seal was recorded by an examiner, and oral habits (finger sucking, lip sucking or lip biting, nail biting, chin resting on a hand) and nose and throat conditions (tendency for nasal obstruction, allergic rhinitis, palatine tonsil hypertrophy) were assessed by a questionnaire completed by the parents. The prevalence of each item was calculated, and binary logistic regression was used to examine the factors related to malocclusion. RESULTS: 62.0% of preschool children in the present study exhibited malocclusion, and 27.8% exhibited incompetent lip seal. Nail biting was the most frequent oral habit with a prevalence of 18.9%. Nasal obstruction was recorded in 30.4% of children. The results of binary logistic regression showed that incompetent lip seal was significantly related to malocclusion, and that nail biting was significantly negatively related. CONCLUSIONS: Incompetent lip seal is significantly associated with malocclusion, but nail biting may not necessarily be a deleterious habit for the occlusion in Japanese preschool children.

Relationship between Dental Occlusion and Maximum Tongue Pressure in Preschool Children Aged 4-6 Years.

Tongue function is regarded as a primary factor in the etiology of malocclusion, but details of the relationship remain unknown. The purpose of the present study was to investigate maximum tongue pressure, in preschool children to examine its relationship with dental occlusion. A total of 477 healthy children (248 boys, 229 girls, aged 4-6 years) were recruited. Dental occlusion was assessed visually to record sagittal, vertical, and transverse malocclusion, and space discrepancies. Maximum tongue pressure was measured using a balloon-based tongue pressure measurement device. Additionally, 72 children (37 boys, 35 girls, aged 4-5 years) were recruited for a 1-year follow-up study. Approximately half of the children (53.5%) showed some type of malocclusion in the present study. Maximum tongue pressure was highest in the 6-year-old children. The results of a two-way ANCOVA show that the effect of age was significant (p < 0.001); however, the effects of sex and dental occlusion, or the interactions among these variables, did not reach significance. Additionally, maximum tongue pressure increased significantly in the 1-year follow-up study (p < 0.001), especially in the normal occlusion group. Maximum tongue pressure increases markedly with growth in the preschool years and can be associated with some types of malocclusion in preschool children.

Tumor necrosis factor alpha activates transcription of the NADPH oxidase organizer 1 (NOXO1) gene and upregulates superoxide production in colon epithelial cells.

NADPH oxidase 1 (Nox1) is a multicomponent enzyme consisting of p22(phox), Nox organizer 1 (NOXO1), Nox1 activator 1, and Rac1. Interleukin-1beta, flagellin, interferon-gamma, and tumor necrosis factor alpha (TNF-alpha) similarly induced Nox1 in a colon cancer cell line (T84), whereas only TNF-alpha fully induced NOXO1 and upregulated superoxide-producing activity by ninefold. This upregulation was canceled by knockdown of NOXO1 with small interfering RNAs. TNF-alpha rapidly phosphorylated p38 mitogen-activated protein kinase and c-Jun N-terminal kinase 1/2, followed by phosphorylation of c-Jun and c-Fos and appearance of an AP-1 binding activity within 30 min. We cloned the 5' flank of the human NOXO1 gene (-3888 to +263 bp), and found that the region between -585 and -452 bp, which contains consensus elements of YY-1, AP-1, and Ets, and the GC-rich region encoding three putative binding sites for SP-1, was crucial for TNF-alpha-dependent promoter activity. Serial mutation analysis of the elements identified an AP-1 binding site (from -561 to -551 bp, agtAAGtcatg) as a crucial element for TNF-alpha-stimulated transcription of the human NOXO1 gene, which was also confirmed by the AP-1 decoy experiments. Thus, TNF-alpha acts as a potent activator of Nox1-based oxidase in colon epithelial cells, suggesting a potential role of this oxidase in inflammation of the colon.

InAs quantum-dot laser utilizing GaAs photonic-crystal line-defect waveguide.

We have observed laser action from optically-pumped InAs-quantum-dots embedded in a line-defect waveguide in an air-bridge type GaAs-photonic-crystal slab (an array of air-holes). The lasing is found to occur without any optical cavity such as a set of Fabry-Perot mirrors. Comparison of the observed transmittance spectrum with the calculated band dispersion of the W3 defect-mode enables us to specify the lasing wavelength as that at the band edge. From this fact it follows that distributed feedback mechanism at the band edge with a vanishingly small group-velocity should be responsible for the present lasing. Usefulness of this kind of compact laser in a future ultrafast planar photonic integrated circuit is discussed.

Multiple supernumerary teeth in the maxillary canine and mandibular premolar regions: a case in the postpermanent dentition.

BACKGROUND: A supernumerary tooth is an extra tooth above the normal number, of which approximately 90% occur in the premaxillary region and show rudimentary forms of crown morphology. Most cases occur singly, with bilateral occurrence in the maxillary canine regions very rare in children with no other associated diseases or syndromes. CASE REPORT: A case of a 14-year-old boy with bilateral supernumerary teeth with normal crown shapes in both the maxillary canine and mandibular premolar regions. The supernumerary teeth in the maxilla were diagnosed at 12.2 years of age and in the mandible at 14.1 years of age. CONCLUSION: Four supernumerary teeth in the maxillary and mandibular canine-premolar region is a rare finding.

Inhibitory effects of cacao bean husk extract on plaque formation in vitro and in vivo.

Cacao bean husk extract (CBH) has been shown to possess antibacterial and antiglucosyltransferase activities through its unsaturated fatty acids and epicatechin polymers, respectively. In the present study, the antiplaque activities of CBH were examined in vitro and in vivo. The extract inhibited the adherence of Streptococcus mutans MT8148 to saliva-coated hydroxyapatite and reduced the accumulation of artificial dental plaque by S. mutans MT8148 on orthodontic wire. The number of mutans streptococci in dental plaque was also significantly reduced when human dental plaque was exposed to CBH from 21 children at 37 degrees C for 1 h. For the in vivo study, 28 volunteers aged 19-29 yr old rinsed their mouth with CBH, before and after each intake of food and before sleeping at night for 4 d without using other oral hygiene procedures. Plaque depositions and the numbers of mutans streptococci were reduced in the subjects, compared with rinsing with 1% ethanol alone. These results indicate that CBH possesses significant antiplaque activity in vitro and in vivo.