Introduction
Methodology
Study design
Setting
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Birth cohort 2012 (8 years old at the start of the field study in 2021)
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Birth cohort 2011 (9 years old at the start of the field study in 2021)
Point | Municipality | Federal state | Simplified BIK categories |
---|---|---|---|
1 | Reutlingen | Baden–Württemberg | Urban region |
2 | Nürnberg | Bavaria | Metropolitan region |
3 | Berlin | Berlin | Metropolitan region |
4 | Lübbenau/Spreewald | Brandenburg | Rural region |
5 | Bremen | Bremen | Metropolitan region |
6 | Hamburg | Hamburg | Metropolitan region |
7 | Ober-Ramstadt | Hesse | Urban region |
8 | Region Lubmin | Mecklenburg–Vorpommern | Rural region |
9 | Braunschweig | Lower Saxony | Urban region |
10 | Düsseldorf | North Rhine–Westphalia | Metropolitan region |
11 | Plaidt | Rhineland-Palatinate | Rural region |
12 | Saarbrücken | Saarland | Urban region |
13 | Hoyerswerda | Saxony | Rural region |
14 | Halle/Saale | Saxony–Anhalt | Urban region |
15 | Großhansdorf | Schleswig–Holstein | Metropolitan region |
16 | Altenburg | Thuringia | Rural region |
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Orthodontic–clinical diagnosis,
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Orthodontic intraoral scan (for subsequent orthodontic model measurement),
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Caries and treatment,
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Plaque and gingival recession, and
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Bleeding of the gums.
Study participants
Inclusion and exclusion criteria
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The target person is registered in one of the randomly selected sample municipalities.
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The target person was born in 2011 or 2012.
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The written consent form, signed by the target person’s parent or guardian, has been provided.
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The target person, or their parent/guardian, have insufficient knowledge of the German language to participate in the study.
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Legal provisions.
Variables
Primary endpoint
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KIG: KIG 1 vs. KIG 2 vs. KIG 3–5 (primary index).
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ICON: Treatment complexity score easy, mild, moderate, difficult, very difficult (secondary index).
Secondary endpoint
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KIG 1–2 vs. KIG 3–5.
Bias
Study size
Quantitative variables
Statistical methods
Results
Calibration results
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Kappa to 0.20: Poor agreement (poor)
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Kappa 0.21–0.40: Fair agreement (fair)
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Kappa 0.41–0.60: Moderate agreement (moderate)
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Kappa 0.61–0.80: Good agreement (good)
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Kappa >0.80: Very good agreement (very good)
Section | Intra-Rater agreement | Inter-Rater agreement |
---|---|---|
Tooth width | Very good (ICC >0.99) | Very good (ICC >0.99) |
Overjet | Very good (ICC >0.94) | Very good (ICC >0.84) |
Overbite | Very good (ICC >0.96) | Very good (ICC >0.91) |
High dental crowns | Very good (ICC >0.97) | Very good (ICC >0.94) |
Front tooth segment | Very good (ICC >0.99) | Very good (ICC >0.99) |
Support zone | Very good (ICC >0.97) | Very good (ICC >0.97) |
Arch length 6‑year molars | Good to very good (ICC: 0.77–0.97) | Moderate to very good (ICC: 0.42–0.91) |
Sample weighting
Survey of nonrespondents
With whom does your child primarily live? | Nonrespondent | Study participant |
---|---|---|
Natural parents | 136 (82.4%) | 548 (76.8%) |
Mother and partner | 7 (4.2%) | 48 (6.7%) |
Father and partner | – | 1 (0.1%) |
Mother | 18 (10.9%) | 90 (12.6%) |
Father | – | 5 (0.7%) |
Grandparents/Other relatives | 1 (0.6%) | – |
Foster parents/Adoptive parents | – | 3 (0.4%) |
In a children’s home | 1 (0.6%) | – |
Information missing | 2 (1.2%) | 19 (2.7%) |
Total | 165 (100%) | 714 (100%) |
How would you describe the conditions of your child’s teeth and gums? | Nonrespondent | Study participant |
---|---|---|
Very bad | – | 3 (0.4%) |
Bad | 2 (1.2%) | 13 (1.8%) |
Moderate | 17 (10.3%) | 115 (16.1%) |
Good | 72 (43.6%) | 405 (56.7%) |
Very good | 74 (44.8%) | 174 (24.4%) |
Information missing | – | 4 (0.6%) |
Total | 165 (100%) | 714 (100%) |
Speaking in general: How would you complete the following sentence? I take my child to the dentist … | Nonrespondent | Study participant |
---|---|---|
I have never taken my child to the dentist | – | 15 (2.1%) |
… only when my child has problems with their teeth | 5 (3.0%) | 44 (6.2%) |
… for occasional check-ups | 17 (10.3%) | 69 (9.7%) |
… for regular check-ups | 141 (85.5%) | 586 (82.1%) |
Information missing | 2 (1.2%) | – |
Total | 165 (100%) | 714 (100%) |
Study participants and realized cases
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Letter undeliverable,
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Deceased,
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Moved, no longer lives in the household,
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Poor command of the German language,
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In quarantine at the relevant time,
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Unable due to acute illness,
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Unable due to being in hospital,
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Unable due to undergoing a course of restorative treatment, or
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Unable due to chronic illness.
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Address in original conditions,
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On vacation/travelling,
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Unable for other reasons,
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Not willing due to lack of time,
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Not willing due to being unconvinced of intent and purpose,
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Not willing for other reasons,
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No information on the target person, could not be contacted,
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Strictly rejected participation for data protection reasons,
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Strictly rejected participation for other reasons, complete objector,
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Did not appear at scheduled appointment, no information on the reasons why,
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Examination terminated, and
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Rejected participation because of doubts relating to the coronavirus disease 2019 (COVID-19) pandemic.
Response rate and utilization
Sample | |
---|---|
Unadjusted gross sample | 1892 |
Quality-neutral drop-outs | 133 |
Adjusted gross sample | 1759 |
Study participants | 714 |
Nonparticipants | 1045 |
Response rate | 40.6% |