Permanent tooth agenesis in Down syndrome

Down syndrome (DS) is one of the commonest chromosomal disorders worldwide. Individuals with DS have a range of oral health problems including a high prevalence of periodontal disease, macroglossia, mouth breathing, bruxism, delayed or ectopic tooth eruption, malformed teeth, malocclusions, tooth agenesis, and supernumerary teeth.

The aim of this review was to evaluate the prevalence and patterns of permanent tooth agenesis in individuals with Down syndrome.

Methods

Searches were conducted in the PubMed, Embase, Web of Science and Cochrane Library databases. Studies (including cross-sectional and longitudinal, retrospective, and prospective) investigating the prevalence and patterns of tooth agenesis in individuals with DS were considered. Case reports and studies with fewer than 10 patients were excluded.

The outcome of interest was the prevalence of permanent tooth agenesis of individual teeth, excluding third molars. Two reviewers independently selected studies. A standard data set was abstracted and study quality assesses using seven criteria and a random-effects meta-analysis performed.

Results

13 studies involving a total of 1080 individuals were included.
Sample sizes ranged from 25- 216 with ages ranging from 5-40 yrs.
The reporting of prevalence rates of individual tooth agenesis was not always complete
- The overall prevalence of permanent tooth agenesis ranged from 0.30 to 0.81 (30–81%), with the majority of the studies (n = 9) presenting prevalence rates of around 60% (± 4%).
- Random effects meta-analysis estimated the overall prevalence of permanent tooth agenesis, excluding third molars = 58.5% (95% CI: 48.9–67.8%)
- Meta-analysis using a quality effect models = 57.2% (95% CI: 47.1–67.1%)
- Meta-analysis using the inverse variance heterogeneity model = 54.6% (95% CI: 43.6–65.5%).
Approximately 23% of those with tooth agenesis had one missing tooth, 32% had two, 14% had three, 12% had four, and 19% had five or more missing teeth.
The single most commonly absent tooth, however, was the mandibular left second mandibular premolar (19.9%), followed by the maxillary left lateral incisor (19.4%).
Little data describing specific tooth agenesis patterns were available.

Conclusions

The authors concluded

In conclusion, individuals with Down syndrome display high prevalence rates and severity of agenesis of permanent teeth. Proper and timely diagnosis of missing permanent teeth is thus necessary, to allow a more comprehensive long-term treatment plan and a more favorable prognosis in these individuals.

Comments

The authors have searched a good range of databases with out date or language restrictions. They have also included a broad range of study designs. Study quality was assessed using a 7 criteria scale and the authors report that the quality of the studies was not always good. Given that the majority of studies were observational the use of a validated tool such as the Newcastle-Ottawa scale might have been more appropriate. The authors also highlight that the majority of patients included were convenience samples. Given how common Down syndrome is the number of included studies is small as is the number of participants. However the author do conducted some meta-analysis that suggests that DS patients do have high prevalence rates. Given that the quality of the evidence has some limitations the estimates are likely to change when and if higher quality studies are conducted.

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