Dental occlusion was defined by Angle in the 1890s and divided into four classes, normal occlusion, Class I, Class II and Class III malocclusion based on the relationship of the upper and lower first molars. Malocclusions may increase the risk of trauma and cause difficulty in mastication, breathing and speaking affecting quality of life. Orthodontic treatment has become an integral part of dental provision so information on the prevalence of malocclusion and level of treatment need is important for health planners and policy makers.
The main aim of this review was to assess the existing literature regarding the prevalence of malocclusions and different orthodontic features in children and adolescents
Methods
A protocol was registered in the PROSPERO database and the review conducted in line with the PRISMA guidelines. Searches were conducted in the PubMed, Cochrane, Embase, Open Grey, and Web of Science databases. Epidemiological surveys, randomized controlled trials, clinical trials, and comparative studies published in Dutch, English, French, German, Portuguese and Spanish and reporting on the prevalence or incidence of dental malocclusions were considered. Initial screening was carried out be 2 reviewers with 3 reviewers extracting data and assessing risk of bias using the the Methodological Index for Non-Randomized Studies (MINORS)
Results
- 123 studies were included
- 42 studies were conducted in Europe, 41 in Asia, 24 in USA, 14 in Africa and 2 in Oceania.
- Malocclusion was assessed using the Björk method (15 studies) Angle Classification (15 studies), the Index of Orthodontic Treatment Need (16 studies), or the Dental Aesthetic index (18 studies ) with most studies using non-validated methods.
- 10 studies assessed the terminal plane of the deciduous molar, with 41.7 ± 15.2% of the included studies having a flush terminal plane, 12.4 ± 8.1% a distal step and 38.5 ± 10.7% a mesial step.
- 52 studies reported Angle class occlusion – See table
| Angle Class | Mean Prevalence | Range |
| Class I “normal occlusion” | 46.3 ± 27.3% | 1.7–93.6% |
| Class I malocclusion | 46.5 ± 17.0% | 7.4–84.0% |
| Class II malocclusion | 25.0 ± 13.2% | 0.8–72.1% |
| Class II,1 malocclusion, | 16.7 ± 12.7% | 1.7–40.0% |
| Class II,2 malocclusion | 4.7 ± 2.4% | 1.4–13.2% |
| Class III malocclusion | 7.0 ± 7.9% | 0.5–39.1% |
- Large variation was observed in the definitions, measurements, and prevalence of overjet and reverse overjet.
- The prevalence of overbite and open bite varied considerably
- The type of crossbite was not specified in 12 studies, and 58 investigated at least one type of crossbite.
| Mean Prevalence | Range | |
| non-specified crossbite | 6.2 ± 7.8% | 1.0–36.0% |
| posterior crossbite | 7.6 ± 6.0% | 0.3–32.0% |
| unilateral crossbite | 8.3 ± 2.9% | 4.0–13.5% |
| bilateral crossbite | 2.5 ± 1.8% | 0.0–6.5% |
- Nine studies dealt with the prevalence of scissor bite, reporting a weighted mean prevalence of 2.2 ± 3.4% (range 0.0–14.3%).
- Presence of a forced bite (crossbite with lateral or frontal shift) was assessed in nine studies and was found in 13.7 ± 7.7% of the included population (range 1.1–22.5%).
- 44 studies reported hypodontia (excluding 3rd molars) with a mean reported prevalence of 6.5 ± 4.2% (range: 0.0–18.6%).
- Hyperdontia was reported in 19 studies with a mean prevalence of 2.1 ± 1.2% (range: 0.2–4.5%).
- Mesiodens showed a weighted mean prevalence of 1.3 ± 0.5% (range: 0.3–1.6%).
- The prevalence of hypo-hyperdontia was 0.4 ± 0.1% (range: 0.3–0.5%).
- Only a few studies included other dental anomalies, such as impacted teeth, ectopic eruption, and transposition of teeth.
- A majority of studies assessing crowding did provide a definition a summary of prevalence is shown the table.
| Mean Prevalence | Range | |
| Overall crowding | 33.8 ± 18.1% | 0.8–93.4% |
| Maxillary arch | 20.8 ± 14.5% | 1.7–77.9% |
| Mandibular arch | 19.7 ± 15.8% | 0.3–83.3% |
- The mean prevalence of spacing was reported in 18.7 ± 13.7% of the samples (range: 1.2–59.5%) and demonstrated 23.4 ± 20.1% (range: 1.8–62.2%) and 12.8 ± 10.6% (range: 1.3–30.0%) prevalence in the upper and lower jaw, respectively.
- The weighted mean prevalence of a midline diastema was reported in 13.8 ± 14.2% (range: 1.0–73.0%).
Conclusions
The authors concluded: –
A plethora of methods to determine the prevalence of malocclusion and orthodontic features was found across the included studies, which makes the data regarding prevalence of malocclusion unreliable. The mean prevalence of Angle Class I, Class II and Class III malocclusion was 51.9% (SD 20.7), 23.8% (SD 14.6) and 6.5% (SD 6.5), respectively. The prevalence of anterior crossbite, posterior crossbite and crossbite with functional shift was 7.8% (SD 6.5), 9.0% (SD 7.34) and 12.2% (SD 7.8), respectively. The prevalence of hypodontia and hyperdontia were reported to be 6.8% (SD 4.2) and 1.8% (SD 1.3), respectively. For impacted teeth, ectopic eruption and transposition, a mean of 4.9% (SD 3.7), 5.4% (SD 3.8) and 0.5% (SD 0.5) was found, respectively. There is an urgent need to establish methodological protocols for epidemiological studies in orthodontics, which should be reached in consensus with academia and professional societies. Only this will allow objective data to be obtained on which recommendations to the healthcare sector and involved stakeholders can be based.
Comments
The authors have searched a number of major databases and included a large number of studies with sample sizes varying from 58 to 13,801. The review authors indicate that only 26% of the included studies undertook a sample size estimation before data collection. As noted above while a number of well know indices were used to collect data most studies used unvalidated methods. The authors summarise a significant amount of information in this review providing overall estimates for prevalence of malocclusions as well as estimates by continent. While the information is helpful the findings should be interpreted cautiously as the included studies do not score well for risk of bias.
Links
Primary Paper
De Ridder L, Aleksieva A, Willems G, Declerck D, Cadenas de Llano-Pérula M. Prevalence of Orthodontic Malocclusions in Healthy Children and Adolescents: A Systematic Review. Int J Environ Res Public Health. 2022 Jun 17;19(12):7446. doi: 10.3390/ijerph19127446. PMID: 35742703; PMCID: PMC9223594.
Other references
Dental Elf – 13th Sep 2021
Dental Elf – 11th Dec 2020
