Influence of non-orthodontic intervention on digit sucking and consequent anterior open bite: a preliminary study

Objectives: This study aimed to assess behavioural and occlusal outcomes of non-orthodontic intervention (NOI) in a sample of children, 4-12 years of age, in Australia, in order to establish clinical relevance. Materials and methods: Data from 91 patient records of 4- to 12-year-old children reporting a habit of digit sucking, from two clinics in north-eastern Australia, were de-identified and used. Each patient had been examined at two visits, separated by an interval of 4 months, using standard clinical procedures. Results: Of the 77 children who received a 4-month NOI, 69 (89.6%) had ceased their digit sucking habit by the end of the NOI period [chi(2) = 67.0, degrees of freedom (d.f.) = 1, P < 0.001]. Of the 72 subjects who had front teeth, the number with anterior open bite decreased from 37 (51.4%) to 12 (16.7%) upon completion of NOI (chi(2) = 21.3, d.f. = 1, P < 0.001). Among the 32 patients with a measurable overjet, the mean overjet was found to decrease from 4.2 +/- 2.4 mm to 3.1 +/- 1.9 mm after implementation of NOI (t = 5.8, d.f. = 31, P < 0.001). Children who received NOI were more likely to quit the digit sucking habit in the 4-month period (P < 0.001, OR = 51.8, 95% CI: 9.8-273.9) and were more likely to appear without anterior open bite at a 4-month recall (P < 0.001, OR = 30.0, 95% CI: 5.9-151.6). Conclusions: This study demonstrated clinical relevance of NOI on the cessation of a digit sucking habit, closure of anterior open bite and reduction of overjet. Further investigations are indicated.