Down syndrome (DS), or trisomy of chromosome 21, is a chromosomal aberration found across all races with a similar prevalence, estimated at 1-3 per 1000 live births worldwide, 1:588 live births in Poland (1-3). The most characteristic phenotypic symptoms include short stature, microcephaly, flat facial profile, flattened occiput, upward slanting palpebral fissures, epicanthus, a small nose with depressed nasal bridge, small, open mouth with an enlarged furrowed tongue without the center line, short neck, and a single palmar crease. The above dysmorphic features are accompanied by moderate to severe mental impairment and congenital malformations, including cardiac, gastrointestinal, urinary and skeletal defects. Also, multiple oral abnormalities are found in the affected patients. These include a highly arched palate, hypotonia of the orbicularis oris muscle, macroglossia, as well as abnormal tooth number and morphology. Disorders of breathing, swallowing or speech contribute to malocclusions (4). Many of the aforementioned factors promote plaque accumulation and the onset of oral conditions, such as gingivitis and dental caries. Additionally, changes in saliva have been observed in DS patients: salivary flow was statistically significantly lower than in the control group, the buffer capacity of saliva was significantly lower and the level of total protein was almost 2 times higher (2, 5). At the same time, concomitant immune deficiency promotes oral diseases and the spread of infections. Since this is particularly dangerous in patients with congenital heart disease increasing the risk of infective endocarditis, it is important for dentists to know the DS phenotype, as well as to be aware of the dental care needs of these patients (6).

The aim of this study was to present the characteristic oral phenotypic features in DS, to assess hygiene, gingival and dental status, as well as the need for conservative treatment.

Children and adolescents of both sexes with DS presenting to the Department of Pediatric Dentistry at the Medical University of Warsaw with the diagnosis of DS by a geneticist confirmed by genetic testing were eligible for the study. Recruitment to the control group was conducted in parallel to DS patients to ensure comparable age and number of the study groups. Inclusion criteria were age between 3 and 18 years, informed written consent from the patient and/or legal guardians to participate in the study, and cooperation allowing for basic dental examination. Children with a history of chronic systemic conditions or chronic medication use were excluded from the control group. The study was part of a project entitled “Risk factors for caries disease in selected genetic syndromes”, which was approved by the Bioethics Committee of the Medical University of Warsaw (No. KB/228/2009). It comprised a physical examination, including an extraoral assessment of facial shape and symmetry, the condition of the skin, lips and corners of the mouth, and an intraoral assessment of the gingiva, hygiene status and dentition. The examination was performed in a dental office setting, in a dental chair, under artificial lighting with the use of a probe and a dental mirror. The Plaque Index (PLI) by Löe & Silness was used to assess hygiene status, and the Gingival Index (GI) by Löe and Sillness (7, 8) was used to assess the gingiva. The teeth 16, 11, 24, 36, 31, 44 (in primary dentition: 55, 51, 63, 75, 71, 83) were indicator teeth. Plaque was assessed in the cervical region of the indicator teeth on four surfaces using a scale from 0 – no plaque to 3 – a thick layer of plaque filling the interdental space. Hygiene status was assessed based on the mean value of ≤ 1 as good, > 1 ≤ 2 as sufficient, and > 2 as unsatisfactory. Gingival condition was assessed on a four-point scale, where 0 – healthy gingiva to 3 – severe inflammation. Gingivitis is assessed as mild, moderate and severe if the mean sum of the values obtained for individual teeth is in the range of 0.1-1.0, 1.1-2.0, and 2.1-3.0, respectively. Dentition was assessed for the number of teeth (hypodontia, hyperdontia, extraction), the presence of carious cavities (according to ICDAS II criteria codes ≥ 3), missing teeth due to caries, and fillings. The frequency and the level of caries were calculated using dmft, DMFT, dmft + DMFT indicators. Indicators of conservative treatment of permanent and deciduous teeth were calculated. The presence of dental malformations in the form of anatomical anomalies, enamel defects (internal discoloration of teeth, limited enamel opacities, diffuse opacities, enamel hypoplasia, including pit hypoplasia, groove hypoplasia, partial or complete absence of enamel according to the modified DDE index (9, 10) were also evaluated. Panoramic radiographs were taken in cooperative children aged ≥ 5 years with medical indications (suspected periapical infections or congenital malformations). Student’s t-test, chi-square test of concordance and Spearman’s rank correlation analysis were used for statistical analysis. The analysis was performed using the R 3.2.5 package (R Core Team 2019) and with a significance level at p = 0.05.