Table 3 GRADE analysis
Certainty assessment | Impact | Certainty | ||||||
|---|---|---|---|---|---|---|---|---|
No. of studies | Study design | Risk of bias | Inconsistency | Indirectness | Imprecision | Other considerations | ||
Reduction in mandibular incisor crowding from mixed to permanent dentition | ||||||||
5 | Observational studies | Serious | Not serious | Not serious | Serious | Dose–response effect detected | Studies reported a spontaneous mandibular incisor crowding reduction of 0.17 ± 1.75 to 2.50 ± 2.12 mm from the mixed to permanent dentition. The magnitude of crowding self-correction in the permanent dentition is directly related to the crowding severity in the mixed dentition. The greater the initial mandibular incisor crowding, the greater the spontaneous correction. Children with a crowding of 3.96 ± 1.86 mm in the mixed dentition had a reduction of 2.50 ± 2.12 in the permanent dentition. On the other hand, those that initially presented 0.7 ± 0.58 mm of mandibular incisor crowding in the mixed dentition presented a 0.12 ± 1.89 mm reduction in the permanent dentition | Moderate ⨁⨁⨁◯ |