Related Experiment Video
Updated: Jan 13, 2026
Author Spotlight: 3D Movement Assessment of Maxillary Posterior Teeth in Clear Aligner Treatment
Published on: February 23, 2024
Long-term changes in overjet in individuals with and without orthodontic treatment : A 30-year cohort study
Jolina Bokan1, Jonas Q Schmid2, Claudius Middelberg1
1Department of Orthodontics, University of Münster, Münster, Germany.
Purpose:
Large overjet increases the risk of traumatic dental injury (TDI). This study, part of the Münster Long-Term Study (MLS), aimed to investigate long-term changes in overjet with or without orthodontic treatment and to evaluate whether correcting large overjet can reduce Decayed, Missing, and Filled Teeth Index (DMFT) scores of maxillary incisors.
Methods:
Eligible for inclusion in this longitudinal cohort study (MLS) were 667 primary school children who underwent two systematic orthodontic examinations between 1981 and 2001 (T0). Data collection at follow-up in 2022-2023 (T1) included a clinical examination and intraoral scans to evaluate overjet, DMFT, TDI and orthodontic treatment history. Participants were divided into treated and untreated groups. Statistical analysis included Mann-Whitney U tests and paired t‑tests, with significance set at α = 0.05.
Results:
A total of 73 participants could be enrolled in the follow-up: 50 treated (female/male: 27/23; mean age 38.3 ± 5.1 years) and 23 untreated (female/male: 10/13; mean age 39.1 ± 6.0 years). The mean observation period was 30.0 ± 5.3 years. At T0, the mean overjet was significantly larger in the treated group than in the untreated group (4.0 ± 1.78 mm vs 2.6 mm ± 0.79, p = 0.002). The treated group showed a significant reduction in overjet from T0 to T1 (p < 0.001), while changes in the untreated group were not significant (p = 0.601). At T1, differences in overjet between groups were no longer significant (p = 0.105) and there was no significant difference in DMFT scores of the maxillary incisors (p = 0.276). TDI of the anterior teeth occurred in 30.0% (n = 15) of the treated group and in 8.7% (n = 2) of the untreated group at T1. Logistic regression analysis showed that each millimeter increase in overjet at T0 was associated with 47% higher odds of TDI (odds ratio 1.47, 95% CI 1.05-2.13).
Conclusion:
Orthodontic treatment can effectively improve overjet in the long-term. However, it did not reduce DMFT scores of the maxillary incisors in this MLS sample.
Related Concept Videos
02:20Longitudinal Research
01:15Teeth
In the bud stage, the tooth germ (an aggregation of cells) starts to form in the developing jawbone. During the cap stage, the tooth germ differentiates into enamel organ, dental papilla, and dental sac, which will later develop into the tooth's enamel, dentin...
01:26Longitudinal Studies
01:26Assessment of the Mouth
Mouth Inspection
The inspection begins with visually examining the mouth for symmetry, color, and size.
01:09Changes in the Appendicular Skeleton with Age
Initially, the limb buds consist of a core of mesenchyme covered by a layer of ectoderm. The ectoderm at the end of the limb bud thickens to form a narrow crest called the apical ectodermal ridge. This ridge stimulates the underlying...
01:21Tooth Anatomy
The Crown, Neck, and Root
The visible part of the tooth is referred to as the crown. It's covered by enamel, the hardest substance in the human body. The crown is uniquely shaped for each type of tooth, allowing for different functions such as cutting, tearing, or...