Dental caries in individuals with Down syndrome: a systematic review

Molecular Detection of Streptococcus downii sp. nov. from Dental Plaque Samples from Patients with Down Syndrome and Non-Syndromic Individuals

A new bacterial species has recently been identified in the dental plaque of an adolescent with Down syndrome. The species is known as Streptococcus downii sp. nov. (abbreviated to S. downii), and it inhibits the growth of S. mutans and certain periodontal pathogens. The aim of this study was to determine the distribution of S. downii in the oral cavity of individuals with Down syndrome. Methods: A specific polymerase chain reaction for the operon of bacteriocin (class IIb lactobin A/cerein 7B family) was designed to detect S. downii in individuals with Down syndrome (n = 200) and in the general population (n = 100). We also compared the whole genome of S. downii and the regions related to its bacteriocins against 127 metagenomes of supragingival plaque of the “Human Microbiome Project”. Results: We detected the specific gene of the S. downii bacteriocin in an individual with Down syndrome (Cq, 34.52; GE/μL, 13.0) and in an individual of the non-syndromic control group (Cq, 34.78 Cq; GE/μL, 4.93). The prevalence of S. downii was ≤1% both in Down syndrome and in the general population, which did not allow for clinical-microbiological correlations to be established. This result was confirmed by detecting only one metagenome with an ANIm with approximately 95% homology and with 100% homology with ORFs that code class IIb lactobiocin A/cerein 7B bacteriocins among the 127 metagenomes of the “Human Microbiome Project” tested. Conclusions: The detection rate of S. downii in the supragingival dental plaque was very low, both in the Down syndrome individuals and in the non-syndromic controls. A clinical-microbiological correlation could therefore not be established.

Limited quality evidence suggests children and adolescents with down syndrome have lower prevalence of dental caries compared to non-syndromic children

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION

Silva MCPMD, Lyra MCA, Almeida HCR, Alencar Filho AV, Heimer MV, Rosenblatt A. Caries experience in children and adolescents with Down Syndrome: A systematic review and meta-analysis. Arch Oral Biol. 2020 Jul;115:104,715. doi:10.1016/j.archoralbio.2020.104715. Epub 2020 Apr 8. PMID: 32,422,361.

SOURCE OF FUNDING

The Hungarian Human Resources Development Operational Program, the Higher Education Excellence Program of the Hungarian Ministry of Human Capacities to the Therapy Research Module of Semmelweis University, National Research, Development and Innovation Office, Hungarian Scientific Research Fund and the Economic Development and Innovation Operative Programme Grant.

TYPE OF STUDY/DESIGN

Systematic review with meta-analysis.

Opportunities, barriers, and recommendations in down syndrome research

BACKGROUND

Recent advances in medical care have increased life expectancy and improved the quality of life for people with Down syndrome (DS). These advances are the result of both pre-clinical and clinical research but much about DS is still poorly understood. In 2020, the NIH announced their plan to update their DS research plan and requested input from the scientific and advocacy community.

OBJECTIVE

The National Down Syndrome Society (NDSS) and the LuMind IDSC Foundation worked together with scientific and medical experts to develop recommendations for the NIH research plan.

METHODS

NDSS and LuMind IDSC assembled over 50 experts across multiple disciplines and organized them in eleven working groups focused on specific issues for people with DS.

RESULTS

This review article summarizes the research gaps and recommendations that have the potential to improve the health and quality of life for people with DS within the next decade.

CONCLUSIONS

This review highlights many of the scientific gaps that exist in DS research. Based on these gaps, a multidisciplinary group of DS experts has made recommendations to advance DS research. This paper may also aid policymakers and the DS community to build a comprehensive national DS research strategy.

Oral microbiome in down syndrome and its implications on oral health

Introduction: The oral cavity harbors an abundant and diverse microbial community (i.e. the microbiome), whose composition and roles in health and disease have been the focus of intense research. Down syndrome (DS) is associated with particular characteristics in the oral cavity, and with a lower incidence of caries and higher incidence of periodontitis and gingivitis compared to control populations. However, the overall composition of the oral microbiome in DS and how it varies with diverse factors like host age or the pH within the mouth are still poorly understood. Methods: Using a Citizen-Science approach in collaboration with DS associations in Spain, we performed 16S rRNA metabarcoding and high-throughput sequencing, combined with culture and proteomics-based identification of fungi to survey the bacterial and fungal oral microbiome in 27 DS persons (age range 7–55) and control samples matched by geographical distribution, age range, and gender.

Results: We found that DS is associated with low salivary pH and less diverse oral microbiomes, which were characterized by lower levels of Alloprevotella, Atopobium, Candidatus Saccharimonas, and higher amounts of Kingella, Staphylococcus, Gemella, Cardiobacterium, Rothia, Actinobacillus, and greater prevalence of Candida.

Conclusion: Altogether, our study provides a first global snapshot of the oral microbiome in DS. Future studies are required to establish whether the observed differences are related to differential pathology in the oral cavity in DS.

Electric toothbrush for biofilm control in individuals with Down syndrome: a crossover randomized clinical trial

Poor oral hygiene seems to be the norm in children and teenagers with Down Syndrome (DS). Advances in design and types of toothbrushes may improve biofilm control. This randomized, single-blind, crossover clinical trial evaluated the effectiveness of electric toothbrushes regarding mechanical control of biofilm in children and teenagers with DS and their cooperation. Twenty-nine participants with DS, aged 6 to 14 years, used both types of toothbrushes: electric (ET) and manual (MT). The order of use of the different types of toothbrushes was randomly defined, including a 7-day period with each type with 7-day washout period in between. The Turesky-Quigley-Hein biofilm index was used before and after brushing to assess the effectiveness of the technique. Frankl's behavioral scale was used during toothbrushing to assess the participants' cooperation. Paired T-test, Mann Whitney, Chi-square, and Fisher's Exact tests were applied, with a significance level of 5%. The quantity of dental biofilm was significantly reduced after both brushing techniques (p < 0.001). However, no significant difference was found in total biofilm (ET: 0.73 ± 0.36; MT: 0.73 ± 0.34; p = 0.985) or % biofilm reduction (ET: 72.22%; MT: 70.96%; p = 0.762) after brushing between techniques or in % biofilm reduction between toothbrushes of age groups (6 -9 years, p = 0.919; 10-14 years, p = 0.671). Participants showed similar cooperation level with the two types of toothbrush (p = 1.000). The use of electric or manual toothbrush had no effect on the quantity of dental biofilm removed in children and teenagers with DS, nor did it influence their cooperation during the procedure.

Dental caries experience, care index and restorative index in children with learning disabilities and children without learning disabilities: a systematic review and meta-analysis

Data sources MEDLINE, PubMed, Scopus and Web of Science.Study selection Two reviewers independently selected observational studies which compared caries experience between children with learning disabilities (CLD) and children with no learning disabilities (CNLD). Data extraction and synthesis DMFT/dmft, Care Index (CI) and Restorative Index (RI) data was extracted from each study. Meta analyses were conducted on the overall data and then on the following subgroups: Down's syndrome, autism and mixed learning disabilities. An adapted Newcastle-Ottawa Scale (NOS) was used to assess bias. Results Twenty five comparative cross sectional studies from eighteen countries were included in the review. The standardised mean difference in DMFT between CLD and CNLD was 0.43 (95% CI; 0.91 to 0.05 I² >95%) and for dmft was 0.41 (95% CI; 0.14 to 0.96 I² >95%). The only significant difference revealed by sub group analyses of the three main disability groups was lower caries experience in the permanent dentition of children with Down's syndrome (SMD = 0.73; 95% CI; 1.28 to 0.18). There was a larger difference between mean CI and mean RI for CLD than for CNLD, however, the standard deviations were large and no variance data was provided so meta-analyses could not be completed.Conclusions Overall there was no difference in caries experience between CLD and CNLD. However, sub group analysis showed that children with Down's syndrome had lower levels of caries than CNLD but this may be due to the delayed eruption of the permanent teeth commonly seen with Down's syndrome. There was limited data suggesting that caries in permanent teeth was more commonly treated by extraction in CLD than in CNLD, however, this was based on only eight studies.

Genotypic diversity and acidogenicity of Streptococcus mutans in Down syndrome children

AIMS

To evaluate the genotypic diversity and acidogenicity of Streptococcus mutans (S. mutans) and the potential association of these factors with dental caries experience in children with DS compared to non-DS children (controls).

METHODS AND RESULTS

Seventeen children (age 6-12 years) with high salivary S. mutans counts (> 2.5 × 10⁵ CFU/mL) were selected and divided into two groups: DS and non-DS. Five children in each group were caries-free, while the remainder had elevated caries experience. S. mutans isolates were obtained from each participant. The genotypic profile of the isolates was analyzed with the AP-PCR methodology. The acidogenicity of a representative strain from each genotype of S. mutans was also evaluated. DS children had 16 different S. mutans genotypes, while the control group had 21. Twelve genotypes were present in both groups and one of them was associated with caries-free status (P < .05). Although the acidogenicity of the genotypes found in DS children was significantly lower (P < .05) compared to controls, this fact was not associated with caries experience in both groups.

CONCLUSIONS

DS children have a lower S. mutans genotypic diversity and genotypes with lower acidogenicity than those of non-DS children. However these findings were not associated with their caries experience.

Dental caries experience, care index and restorative index in children with learning disabilities and children without learning disabilities; a systematic review and meta-analysis

Background

Children with learning disabilities (CLD) have worse health outcomes than children with no learning disabilities (CNLD). This systematic review compared caries experience and met dental care need for CLD to CNLD using Decayed, Missing, Filled Permanent Teeth (DMFT) and decayed, missing/extracted, filled primary teeth (dmft/deft), care index (CI), and restorative index (RI) values.

Methods

Without date or language restrictions four databases were searched for; cross-sectional studies comparing caries experience and CI/ RI in CLD matched to groups of CNLD. Screening and data extraction were carried out independently and in duplicate. Risk of bias was assessed using the Newcastle-Ottawa Scale. Meta-analyses were carried out (random effects model).

Results

There were 25 articles with 3976 children (1 to 18 years old), from 18 countries, fitting the inclusion criteria. Children with; Down syndrome were investigated in 11 studies, autism in 8 and mixed learning disabilities in 6. The overall mean DMFT for CLD was 2.31 (standard deviation±1.97; range 0.22 to 7.2) and for CNLD was 2.51 (±2.14; 0.37 to 4.76). Using standardised mean difference (SMD), meta-analysis showed no evidence of a difference between CLD and CNLD (n = 16 studies) for caries experience (SMD = -0.43; 95%CI = -0.91 to 0.05). This was similar for sub-groups of children with autism (SMD = -0.28; 95%CI = 1.31 to 0.75) and mixed disabilities (SMD = 0.26; 95%CI = -0.94 to 1.47). However, for children with Down syndrome, caries experience was lower for CLD than CNLD (SMD = -0.73; 95%CI = -1.28 to − 0.18). For primary teeth, mean dmft/deft was 2.24 for CLD and 2.48 for CNLD (n = 8 studies). Meta-analyses showed no evidence of a difference between CLD and CNLD for caries experience across all disability groups (SMD = 0.41; 95% CI = -0.14 to 0.96), or in sub-groups: Down syndrome (SMD = 0.55; 95%CI- = − 0.40 to 1.52), autism (SMD = 0.43; 95%CI = -0.53 to 2.39) and mixed disabilities (SMD = -0.10; 95%CI = -0.34 to 0.14). The studies’ risk of bias were medium to high.

Conclusion

There was no evidence of a difference in caries levels in primary or permanent dentitions for CLD and CNLD. This was similar for learning disability sub-groups, except for Down syndrome where dental caries levels in permanent teeth was lower. Data on met need for dental caries was inconclusive.

Trial registration

The protocol was published in PROSPERO: CRD42017068964 (June 8th, 2017).

Electronic supplementary material

The online version of this article (10.1186/s12903-019-0795-4) contains supplementary material, which is available to authorized users.

Malocclusion in children and adolescents with Down syndrome: A systematic review and meta-analysis

BACKGROUND

Previous studies have shown a high prevalence of malocclusion in people with Down syndrome (DS) compared to individuals without DS, but no systematic review to summarize the evidence on this topic has been performed thus far.

AIM

To evaluate whether children/adolescents with DS are more affected by malocclusion than those without DS.

DESIGN

A search was performed in seven electronic databases. The quality of the included studies was assessed using the Newcastle-Ottawa Scale. The strength of the evidence from the selected studies was evaluated by the Grading of Recommendations Assessment, Development and Evaluation system.

RESULTS

Eleven publications were included in the systematic review and eight were meta-analysed. The meta-analysis showed that malocclusion was more prevalent in children/adolescents with DS for Angle Class III (risk difference [RD] = 0.40; confidence interval [CI] = 0.33, 0.46), posterior crossbite (risk ratio [RR] = 3.09; CI = 2.02, 4.73), anterior crossbite (RR = 2.18; CI = 1.41, 3.39), and anterior open bite (RD = 0.21; CI = 0.06, 0.36).

CONCLUSION

The occurrence of malocclusion was higher in children/adolescents with DS compared to individuals without the syndrome. The strength of the evidence of the studies analysed, however, was considered moderate and low.

Oral Health Status among Children with Down Syndrome in Dubai, United Arab Emirates

Objectives:

The purpose of this study was to assess the oral health status in Down syndrome (DS) children in Dubai, United Arab Emirates.

Materials and Methods:

A total of 106 DS children (mean age = 9.3 ± 2.8) and 125 healthy children (mean age = 11.7 ± 4.4) were recruited from both special needs centers and private/public schools in Dubai. A dental examination for decayed-missing-filled teeth (DMFT) in deciduous dentition/DMFT in permanent dentition indices, simplified oral hygiene index, calculus index (CI), were carried out. In addition, occlusal, dentofacial, soft-tissue abnormalities, and erosion were assessed. Statistical analysis was conducted using SPSS for Windows, version 20.0 (SPSS Inc., Chicago, IL, USA).

Results:

The mean number of DMFT in DS children was significantly higher than that in healthy children. DS children in the primary dentition group had higher restorative index and Met Need Index scores than the control group. On the other hand, CI was found to be significantly higher among children with DS compared to healthy controls (P < 0.004). DS children had a significantly higher proportion of open bite and other occlusal problems. Class III molar angle malocclusion was significantly higher in DS (66%) compared to controls (11.2%). Erosion was significantly higher among DS children compared to healthy control (34% vs. 15.3%).

Conclusions:

DS children in Dubai had higher caries rate compared to healthy children. DS group received more restorations and dental treatment compared to the control group. More to add, DS children had significantly more calculus, erosion, and malocclusion problems.

Insights into the Potential Role of Mercury in Alzheimer's Disease

Mercury (Hg), which is a non-essential element, is considered a highly toxic pollutant for biological systems even when present at trace levels. Elevated Hg exposure with the growing release of atmospheric pollutant Hg and rising accumulations of mono-methylmercury (highly neurotoxic) in seafood products have increased its toxic potential for humans. This review aims to highlight the potential relationship between Hg exposure and Alzheimer's disease (AD), based on the existing literature in the field. Recent reports have hypothesized that Hg exposure could increase the potential risk of developing AD. Also, AD is known as a complex neurological disorder with increased amounts of both extracellular neuritic plaques and intracellular neurofibrillary tangles, which may also be related to lifestyle and genetic variables. Research reports on AD and relationships between Hg and AD indicate that neurotransmitters such as serotonin, acetylcholine, dopamine, norepinephrine, and glutamate are dysregulated in patients with AD. Many researchers have suggested that AD patients should be evaluated for Hg exposure and toxicity. Some authors suggest further exploration of the Hg concentrations in AD patients. Dysfunctional signaling pathways in AD and Hg exposure appear to be interlinked with some driving factors such as arachidonic acid, homocysteine, dehydroepiandrosterone (DHEA) sulfate, hydrogen peroxide, glucosamine glycans, glutathione, acetyl-L carnitine, melatonin, and HDL. This evidence suggests the need for a better understanding of the relationship between AD and Hg exposure, and potential mechanisms underlying the effects of Hg exposure on regional brain functions. Also, further studies evaluating brain functions are needed to explore the long-term effects of subclinical and untreated Hg toxicity on the brain function of AD patients.

Critical appraisal of methodological quality of Systematic Reviews and Meta-analysis in Paediatric Dentistry journals

OBJECTIVE

To systematically assess the methodological quality of Systematic Reviews (SRs) and Meta-Analyses (MA) published in Paediatric Dentistry journals and to analyse the relationship between the authors, journals, country, review topic, and the year of publication to the methodological quality of SRs and MA.

DESIGN

Paediatric Dentistry journals ranked in the top five of the h5 index of Google Scholar Metrics were selected. SRs with MA were searched independently by two reviewers using PubMed and Scopus databases until December 2017. Methodological quality was assessed using A Measurement Tool to Assess Systematic Reviews (AMSTAR) tool. Statistical significance was set at P < 0.05 and Mann-Whitney U test and Kruskal-Wallis test was employed for comparing the AMSTAR score with the journal characteristics.

RESULTS

Finally, 24 SRs with MA were included. The overall AMSTAR score of SRs and MA published in paediatric dentistry journals was 7.08 ± 2.41. No statistically significant differences were found between the country, journal or focus of study to the quality of SRs except the number of authors and the year of publication (P < 0.05).

CONCLUSIONS

The quality of SRs and MA in leading Paediatric Dentistry journals were evaluated with AMSTAR tool and areas where quality could be improved were identified.

Salivary secretory IgA concentration and dental caries in children with Down syndrome

PURPOSE

To evaluate the relationship between salivary secretory immunoglobulin A (sIgA) concentration and dental caries in children with Down syndrome (DS) and compare it with findings in non-DS children.

METHODS

The sample comprised 61 DS children and 52 non-DS children, aged 6 to 14 years. Caries experience, plaque index (PI), and gingival bleeding index (GBI) were recorded. Saliva samples were collected from all children. Total salivary sIgA concentrations were determined using an enzymatic assay method.

RESULTS

Caries experience in primary and permanent dentitions were similar in DS and non-DS children. However, PI and GBI values were significantly lower in DS compared to non-DS children. DS children had higher salivary sIgA concentrations compared to non-DS children. No difference in sIgA concentration was observed between children with and without caries experience in either group.

CONCLUSIONS

DS children have higher salivary sIgA concentrations than non-DS children. However, this finding did not correlate with caries experience in the study population.