Objective.  The X‐linked hypohidrotic ectodermal dysplasia (HED) is the most common type of ectodermal dysplasia. The clinical identification of possible heterozygous females can be difficult because of the varying degrees of clinical signs caused by X‐chromosome inactivation. This study is the first to elaborate on anomalies of tooth formation found in a group of hemizygous males and heterozygous females with known ED1 mutations. These tooth anomalies may be used as dental biomarkers for heterozygous females, enabling an earlier diagnosis, and therefore, better treatment and genetic counselling. Methods.  Anomalies of tooth formation were examined using panoramic radiographs, dental casts and oral photographs in hemizygous males and heterozygous females who were identified by molecular genetic analysis. The results were compared to existing controls and normative data. Results.  All affected males had multiple missing permanent teeth and tooth malformations. The heterozygous females had a significantly higher frequency of agenesis of permanent teeth compared to normative data. The heterozygous females had an increased prevalence of tooth malformations and reduced tooth size, especially in the mesiodistal dimension. Conclusions.  We conclude that observed anomalies of tooth formation may be used as dental biomarkers in the clinical identification of potentially heterozygous females.

This study aimed to investigate genotype and phenotype in males affected with X-linked hypohidrotic ectodermal dysplasia (HED) and in female carriers, to analyse a possible genotype-phenotype correlation, and to analyse a possible relation between severity of the symptoms and the X-chromosome inactivation pattern in female carriers. The study group comprised 67 patients from 19 families (24 affected males and 43 female carriers). All participants had clinical signs of ectodermal dysplasia and a disease-causing EDA mutation. The EDA gene was screened for mutations by single-stranded conformational polymorphism and direct sequencing. Multiplex ligation-dependent probe amplification (MLPA) analysis was used to detect deletions/duplications in female probands. Sixteen different EDA mutations were detected in the 19 families, nine not described previously. The MLPA analysis detected a deletion of exon 1 in one female proband. No genotype-phenotype correlations were observed, and female carriers did not exhibit a skewed X-chromosome inactivation pattern. However, in two female carriers with pronounced clinical symptoms, in whom the parental origin of each allele was known, we observed that mainly the normal allele was inactivated.

Background: No comprehensive patient‐centered and clinical evaluations of the functional effect of treatment with implant‐supported single crowns (ISSC) have been reported previously.Objective: To investigate whether and how treatment with ISSC affects masticatory function and Oral Health‐Related Quality of Life (OHRQoL) in subjects with tooth agenesis.Material and methods: In nine females and nine males (32±10 years) with agenesis treated with one to four ISSC (68% in the premolar region), the treatment effect and masticatory function were assessed. The evaluation was performed first after implant placement shortly before crown cementation, and again 1 month after cementation. It consisted of questionnaires [including Oral Health Impact Profile (OHIP‐49)] and functional examination with plastic strips, the Dental Prescale Film and the Occluzer system, Xylitol color‐changeable gum and slices of Granny Smith apple.Results: The patients' satisfaction with treatment was high and they experienced a significant overall improvement in their OHRQoL (on average 13% reduction in the total OHIP scores). The cementation of the crowns was associated with a significant increase in the number of near occlusal tooth contacts, contact area, bite force, and masticatory ability and performance. Correspondingly, there was a significant, positive correlation between the number of tooth contacts and (1) occlusal contact area, (2) bite force, and (3) masticatory performance.Conclusion: Treatment with ISSCs in subjects with tooth agenesis significantly increased masticatory function subjectively and clinically as well as OHRQoL. However, as the functional parameters before replacement of the teeth corresponded to values in subjects with complete dentitions, the functional importance of the increase may be questioned. To cite this article: 
Goshima K, Lexner MO, Thomsen CE, Miura H, Gotfredsen K, Bakke M. Functional aspects of treatment with implant‐supported single crowns: a quality control study in subjects with tooth agenesis.
Clin. Oral Impl. Res. 21, 2009; 108–114.

BACKGROUND.  Early in life, vaginally delivered infants exhibit a different composition of the gut flora compared with infants delivered by caesarean section (C-section); however, it is unclear whether this also applies to the oral cavity. AIM.  To investigate and compare the oral microbial profile between infants delivered vaginally and by C-section. DESIGN.  This is a cross-sectional case-control study. Eighty-four infants delivered either vaginally (n = 42) or by C-section (n = 42) were randomly selected from the 2009 birth cohort at the County Hospital in Halmstad, Sweden. Medically compromised and premature children (<32 weeks) were excluded. The mean age was 8.25 months (range 6-10 months), and parents were asked to complete a questionnaire on socioeconomic factors, lifestyle, and hygiene habits. Saliva was collected and analysed using checkerboard DNA-DNA hybridization. RESULTS.  A higher prevalence of salivary Streptococcus salivarius, Lactobacillus curvata, Lactobacillus salivarius, and Lactobacuillus casei was detected in infants delivered vaginally (P < 0.05). The caries-associated bacteria Streptococcus mutans and Streptococcus sobrinus were detected in 63% and 59% of all children, respectively. CONCLUSION.  A significantly higher prevalence of certain strains of health-related streptococci and lactobacilli was found in vaginally delivered infants compared with infants delivered by C-section. The possible long-term effects on oral health need to be further investigated.

Saliva flow and composition may be used as part of a comprehensive clinical examination to identify potential female carriers of HED.