0915 Sleep Patterns and the Effect of Late Bedtime on School-Age Children and Adolescents: Preliminary Results

17 USC 105 interim-entered record; under review.The article of record as published may be found at https://doi.org/10.1093/sleep/zsaa056.911Introduction: School-age children (6-13yrs) and teenagers (14-17yrs) should receive 9-11hrs and 8-10hrs of sleep/day, respectively. Several studies have shown, however, that these age groups are chronically sleep deprived. Our study assessed the sleep patterns of a sample of children and teenagers in Athens, Greece. The study is part of a larger project investigating the association between orthodontic treatment and sleep disturbances. Methods: Participants (N=27; 69% females; 21 school-age children 9-13yrs, 6 teenagers 14-17yrs) were under treatment in the Orthodontic Clinic of the National and Kapodistrian University. Sleep was assessed with actigraphy/logs for 59±19 days. Results: Participants slept on average 7.36±0.42hrs/day. Nighttime sleep was on average 7.23±0.43hrs (percentage sleep: 87.3%±3.38%). Four (14.8%) participants napped at least once/week. Compared to the lowest sleep duration recommended for their age group, participants showed a chronic sleep deficit of 1.42±0.52hrs/day (range: 0.32-2.15hrs). The younger age group had an average sleep deficit of ~1.6hrs compared to ~0.8hrs for the teenagers (p=0.006). During the school year, daily sleep duration increased by ~0.73hrs on weekends (7.78±0.67hrs) compared to school nights (7.05±0.48hrs; p<0.001). On average, school-age participants slept from 23:13 (±31min) until 7:19 (±22min) on school nights and from 23:23 (±2:72hrs) until 8:49 (±39min) on weekends. Teenagers slept from 00:34 (±36min) until 7:40 (±14min) on school nights and from 01:34 (±41min) until 10:34 (±48min) on weekends. Conclusion: Our findings verify earlier survey results showing that restricted sleep is a problem for children and adolescents in Greece. To our surprise, both age groups go to bed quite late. The impact of late bedtime on sleep duration, however, is larger in the younger group due to their larger sleep needs. In contrast to earlier research in rural areas, napping was not common in our urban sample, probably due to extracurricular activities and studying at home

A multidisciplinary treatment of congenitally missing maxillary lateral incisors: a 14-year follow-up case report

Absence of the maxillary lateral incisor creates an aesthetic problem which can be managed in various ways. The condition requires careful treatment planning and consideration of the options and outcomes following either space closure or prosthetic replacement. Recent developments in restorative dentistry have warranted a re-evaluation of the approach to this clinical situation. Factors relating both to the patient and the teeth, including the presentation of malocclusion and the effect on the occlusion must be considered. The objective of this study was to describe the etiology, prevalence and alternative treatment modalities for dental agenesis and to present a clinical case of agenesis of the maxillary lateral incisors treated by the closure of excessive spaces and canine re-anatomization. A clinical case is presented to illustrate the interdisciplinary approach between orthodontics and restorative dentistry for improved esthetic results. In this report, the treatment of a girl with a Class II malocclusion of molars and canines with missing maxillary lateral incisors and convex facial profile is shown. Treatment was successfully achieved and included the space closure of the areas corresponding to the missing upper lateral incisors, through movement of the canines and the posterior teeth to mesial by fixed appliances as well as the canines transformation in the maxillary lateral incisors. This is a 14-year follow-up case report involving orthodontics and restorative dentistry in which pretreatment, posttreatment, and long-term follow-up records for the patient are presented

Functional analysis of Ectodysplasin-A mutations causing selective tooth agenesis.

Mutations of the Ectodysplasin-A (EDA) gene are generally associated with the syndrome hypohidrotic ectodermal dysplasia (MIM 305100), but they can also manifest as selective, non-syndromic tooth agenesis (MIM300606). We have performed an in vitro functional analysis of six selective tooth agenesis-causing EDA mutations (one novel and five known) that are located in the C-terminal tumor necrosis factor homology domain of the protein. Our study reveals that expression, receptor binding or signaling capability of the mutant EDA1 proteins is only impaired in contrast to syndrome-causing mutations, which we have previously shown to abolish EDA1 expression, receptor binding or signaling. Our results support a model in which the development of the human dentition, especially of anterior teeth, requires the highest level of EDA-receptor signaling, whereas other ectodermal appendages, including posterior teeth, have less stringent requirements and form normally in response to EDA mutations with reduced activity

The role of peptides in bone healing and regeneration: A systematic review

Background: Bone tissue engineering and the research surrounding peptides has expanded significantly over the last few decades. Several peptides have been shown to support and stimulate the bone healing response and have been proposed as therapeutic vehicles for clinical use. The aim of this comprehensive review is to present the clinical and experimental studies analysing the potential role of peptides for bone healing and bone regeneration. Methods: A systematic review according to PRISMA guidelines was conducted. Articles presenting peptides capable of exerting an upregulatory effect on osteoprogenitor cells and bone healing were included in the study. Results: Based on the available literature, a significant amount of experimental in vitro and in vivo evidence exists. Several peptides were found to upregulate the bone healing response in experimental models and could act as potential candidates for future clinical applications. However, from the available peptides that reached the level of clinical trials, the presented results are limited. Conclusion: Further research is desirable to shed more light into the processes governing the osteoprogenitor cellular responses. With further advances in the field of biomimetic materials and scaffolds, new treatment modalities for bone repair will emerge

MSX1 Polymorphism Associated with Risk of Oral Cleft in Korea: Evidence from Case-Parent Trio and Case-Control Studies

Orofacial clefts, including cleft lip with or without palate (CL/P) and cleft palate (CP), are one of the most common congenital malformations in Asian populations, where the rate of incidence is higher than in European or other racial groups. A number of candidate genes have been identified for orofacial clefts, although no single candidate has been consistently identified in all studies. We performed case-parent trio and case-control studies on 6 single nucleotide polymorphisms (SNPs) in the MSX1 gene using a sample of 52 CL/P and CP probands from Korea. In the case-control study, the allele frequencies of 6 MSX1 SNPs were compared between 52 oral cleft cases and 96 unmatched controls. For the case-parent trio study, single-marker and haplotype-based tests of transmission disequilibrium using allelic and genotypic tests revealed significant evidence of linkage in the presence of disequilibrium for 1170 G/A of exon 2. With the GG genotype as a reference group among GG, GA, and AA genotypes at 1170G/A, the disease risk decreased with the presence of the A allele (AA genotype: OR = 0.26, 95% CI = 0.10-0.99). These results are consistent with evidence from other studies in the US and Chile and confirm the importance of the MSX1 genotype in determining the risk of CL/P and CP in Koreans

Experimental Animal Models in Periodontology: A Review

In periodontal research, animal studies are complementary to in vitro experiments prior to testing new treatments. Animal models should make possible the validation of hypotheses and prove the safety and efficacy of new regenerating approaches using biomaterials, growth factors or stem cells. A review of the literature was carried out by using electronic databases (PubMed, ISI Web of Science). Numerous animal models in different species such as rats, hamsters, rabbits, ferrets, canines and primates have been used for modeling human periodontal diseases and treatments. However, both the anatomy and physiopathology of animals are different from those of humans, making difficult the evaluation of new therapies. Experimental models have been developed in order to reproduce major periodontal diseases (gingivitis, periodontitis), their pathogenesis and to investigate new surgical techniques. The aim of this review is to define the most pertinent animal models for periodontal research depending on the hypothesis and expected results

PAX9 polymorphism and susceptibility to sporadic non-syndromic severe anodontia: a case-control study in southwest China

Our research aimed to look into the clinical traits and genetic mutations in sporadic non-syndromic anodontia and to gain insight into the role of mutations of PAX9, MSX1, AXIN2 and EDA in anodontia phenotypes, especially for the PAX9. MATERIAL AND METHODS: The female proband and her family members from the ethnic Han families underwent complete oral examinations and received a retrospective review. Venous blood samples were obtained to screen variants in the PAX9, MSX1, AXIN2, and EDA genes. A case-control study was performed on 50 subjects with sporadic tooth agenesis (cases) and 100 healthy controls, which genotyped a PAX9 gene polymorphism (rs4904210). RESULTS: Intra-oral and panoramic radiographs revealed that the female proband had anodontia denoted by the complete absence of teeth in both the primary and secondary dentitions, while all her family members maintained normal dentitions. Detected in the female proband were variants of the PAX9 and AXIN2 including A240P (rs4904210) of the PAX9, c.148C>T (rs2240308), c.1365A>G (rs9915936) and c.1386C>T (rs1133683) of the AXIN2. The same variants were present in her unaffected younger brother. The PAX9 variations were in a different state in her parents. Mutations in the MSX1 and EDA genes were not identified. No significant diferences were found in the allele and genotype frequencies of the PAX9 polymorphism between the controls and the subjects with sporadic tooth agenesis. CONCLUSIONS: These results suggest that the association of A240P with sporadic tooth agenesis still remains obscure, especially for different populations. The genotype/phenotype correlation in congenital anodontia should be verified

Teeth in a genetic age

The outline of the information needed to create a human being, the draft sequences of the human genome, are now published. Refinement of the data lies ahead, but the implications for studying our biological selves are already profound. The Human Genome Project has assisted significantly in the investigation of dental anomalies and specifically in the genetic roots of tooth agenesis. Dentistry will gain a great deal in diagnosis, prevention, and therapeutics from the interpretation and application of the genetic research data. Copyright 2002, Elsevier Science (USA). All rights reserved