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Table 7 Multivariable analysis evaluating the impact of self-ligating (SL) brackets on number of visits within a treatment, treatment duration, and number of extraction cases

From: Root resorption, treatment time and extraction rate during orthodontic treatment with self-ligating and conventional brackets

  Number of visitsa Duration of treatmenta Extractionb
Parameter estimate (β)c p-value 95% CI Parameter estimate (β)c p-value 95% CI ORd p-value 95% CI
SL -0.50 0.14 -1.15; 0.16 3.52 <0.001 2.07; 4.96 0.84 0.76 0.29; 2.49
Non-SL 0         
  1. aANCOVA model adjusted for gender, age, space closure, and treatment mechanic,.bbinary logistic regression adjusted for gender and age, cregression coefficient: average difference in number of visits / duration of treatment [in months] between the Non-SL (reference group) and the SL group (comparison group), dOdds ratio: chance of extraction occurring in the SL group compared to the chance of extraction occurring in the Non-SL group. An OR of 1 indicate equal chances in both groups, OR > 1 indicate higher chance in the SL vs. non-SL group, OR < 1 indicate lower chance in the SL vs. Non-SL group, d Reference category.
  2. CI confidence interval, OR: odds ratio, rRR: relative root resorption, sEARR: severe external apical root resorptions, SL: self-ligating.