Effect of Finger Sucking, Nail Biting, and Salivary Level of Growth Hormone on Type of Malocclusion among Primary School Students: An Analytical Cross-Sectional Study

 We aimed to assess the effect of finger-sucking, nail-biting, and salivary levels of growth hormone on the type of malocclusion among primary school students. 

This study was conducted among 10–11-year-old (4th and 5th class of the elementary schools) students in the center of Karbala city from February to June 2021 using a multistage cluster random sampling technique. Data related to oral habits were obtained using questionnaires, which were distributed among the students and collected the next day after being answered and signed by the parents. Unstimulated saliva samples were collected, and salivary levels of growth hormone were assessed using the enzyme-linked immunosorbent assay (ELISA) method. Data were analyzed via multinomial logistic regression using R software. 

The finger sucking was a significant predictor for class 2 malocclusion (p < 0.001). Night-time finger sucking was a significant predictor for class 3 malocclusion (p = 0.031). Salivary levels of growth hormone and nail-biting were not significant predictors for malocclusion (p ˃ 0.05). Also, finger sucking was a marginally nonsignificant predicator for class 3 malocclusion (p = 0.057). 

 Cross-sectional studies capture data at a single point in time, and they cannot establish a cause-and-effect relationship. More cohort studies are required to reach a conclusion about the effect of non-nutritive sucking habits such as finger sucking, nail-biting and salivary level of growth hormone on type of malocclusion.