Increased overjet: increased risk of dental trauma

Traumatic dental injury (TDI) is common in children with studies suggesting that prevalence ranges between 15-30 %. An association between TDI and increased overjet was suggested in the 1950s but findings from observational studies have been inconsistent.

The aim of this review was to assess the association between overjet and TDI.

Methods

Searches were conducted in the Medline/PubMed, SCOPUS and Google Scholar databases. Cross-sectional or case-control studies published between 1990-2014 were considered. Selected primary studies were divided into subsets: ‘primary teeth, overjet threshold 3-4 mm’; ‘permanent teeth, overjet threshold 3-4 mm’ (Permanent3); ‘permanent teeth, overjet threshold 6 ± 1 mm’ (Permanent6). The pooled odds ratio (ORs) for TDI due to large overjet with 95% CIs were estimated for each study subset.

Results

54 studies involving >10,000 patients were included from Africa, America, Asia and Europe.
Most studies included children and adolescents but 3 included adults.
Pooled odds ratios
- Primary teeth with 3-4 mm overjet = 2.31 (95%CI; 1.01 – 5.27)
- Permanent teeth with 3-4 mm overjet = 2.01 (95%CI; 1.39 – 2.91)
- Permanent teeth with 6 ± 1 mm overjet = = 2.24 (95%CI; 1.56 – 3.21)
The population attributable fraction (PAF)
- 3-4 mm overjet = 21.76% (95%CI; 9.70 -34.46%)
- 6 ± 1 mm overjet = 10.17% (95%CI; 4.86 – 16.79%)

Conclusions

The authors concluded

The present meta-analysis of observational studies showed that large overjet may double or even triple the risk for TDI to anterior primary and permanent teeth and that, at global level, large overjet is partly responsible for 100–300 million TDIs. These figures do not require further comments and corroborate the idea that the global burden of TDI is very high and that large overjet has a significantly high impact on this figure. The reported pooled ORs help assess the patients’ risk for TDI and, therefore, to decide whether preventive measures must be taken to decrease such a risk. These measures may range from orthodontic treatment to mouth protection for exposed individuals at high TDI risk and tutors’ counselling to increase their awareness towards their children proneness to TDI while they are playing or are at home. Well-designed clinical trials and good-quality systematic reviews are necessary to assess the effectiveness of these measures to decrease the risk for dental injuries in subjects with large overjet.

Commentary

This interesting meta-analysis of observational studies suggests that a large overjet may double the risk of a TDI and estimates the global impact of this problem. Although many The PAF estimates suggest that approximated 22% of TDIs are attributable to large overjet in patients with overjet of 3-4 mm and 10% in those with 6 ± 1 mm overjet which is perhaps counterintuitive as you might think that the larger overjet posed a larger risk?

TDIs are left untreated the potential initial and ongoing treatment costs are high. The 2014 Cochrane review by Thiruvenkatachari et al (Dental Elf – 7^th Jan 2014) note that the only benefit for providing early orthodontic treatment for patients with class II malocclusions was a reduction in the incidence of incisal trauma but here again there are treatment costs and potential for other adverse outcomes.