Correlation Between Early Childhood Oral Habits and Developing Malocclusions: A Pediatric-Orthodontic Cohort Analysis

Abstract

Aim:

To use a cohort-based orthodontic analysis to examine the association between early childhood oral habits (such as mouth breathing, tongue thrusting, dummy use, and thumb sucking) and the occurrence, kind, and severity of developing malocclusions in a pediatric population.

Methodology:

A 2-year cohort study followed 220 children (ages 3–6) with full primary dentition and no orthodontic history. Examinations at baseline, 12, and 24 months assessed malocclusion, while caregiver questionnaires recorded oral habits. Logistic regression, adjusted for age, sex, and socioeconomic status, analyzed the impact of habits persisting over 3 years.

Results:

Malocclusion prevalence rose from 37.7% to 48.2%. Dummy use past age 3 was linked to posterior crossbite (OR = 3.58), and thumb/finger sucking past age 4 to anterior open bite (OR = 4.21). Tongue thrusting related to anterior open bite and mouth breathing to narrow maxilla and overjet. Duration and frequency predicted severity more than habit type.

Conclusion:

Prolonged oral habits greatly increase malocclusion risk. Stopping them before age 3 or 4 can prevent dentoalveolar changes and reduce future orthodontic needs.

INTRODUCTION

Malocclusion—misalignment between the upper and lower teeth—is one of the most common developmental issues in children. Its causes include genetic factors, environmental influences, and acquired functional behaviors. Among environmental factors, non-nutritive oral habits such as thumb sucking, prolonged pacifier use, tongue thrusting, and mouth breathing are strongly linked to malocclusion.

Thumb sucking exerts continuous forward pressure on the maxillary structures, contributing to increased overjet, anterior open bite, and posterior crossbite in children over 3 years old.[1,2] Prolonged pacifier use has similar effects, altering occlusal relationships and dental arch form.[3] Mouth breathing—often due to chronic airway obstruction—can cause “long-face syndrome,” characterized by a posterior crossbite, narrow maxilla, and steep mandibular plane angle.[4]

While cross-sectional and case-control studies have shown associations between these habits and malocclusion, they cannot confirm causation or track developmental timing. This highlights the importance of longitudinal cohort studies that follow children over time to better understand how early oral behaviors influence the onset, type, and severity of malocclusions. This study addresses this gap, aiming to guide early orthodontic prevention and intervention.

METHODOLOGY

A longitudinal observational design was used for this cohort analysis in order to examine the connection between the development of malocclusions and early childhood oral habits. Children between the ages of 3 and 6 at baseline made up the study population. They were sourced from community health centers and pediatric dental clinics, and their inclusion criteria included having a complete primary dentition and having never had orthodontic treatment. The presence, kind, frequency, and duration of oral habits, such as thumb/finger sucking, dummy use, tongue thrusting, and mouth breathing, were recorded in structured questionnaires filled out by the participants’ carers. Calibrated pediatric dentists and orthodontists performed clinical examinations evaluating sagittal, vertical, and transverse occlusal relationships using standardized diagnostic criteria for malocclusion. In order to document any changes in occlusion status over time, baseline evaluations were followed by two follow-up assessments spaced 12 months apart. Repeated intra-examiner evaluations and examiner calibration sessions guaranteed reliability. While logistic regression models were used to assess relationships between particular oral habits and malocclusion outcomes, controlling for potential confounders such as age, sex, and socioeconomic background, descriptive statistics were used to summarize habit prevalence and malocclusion types. Before participation, all parents or guardians gave their informed consent, and the institutional review board granted ethical approval.

RESULT

In this 2-year study of 220 children (mean age 4.5 years; 51.8% male), pacifier use (41.4%) was the most common habit, followed by thumb/finger sucking (29.1%), mouth breathing (18.6%), and tongue thrusting (10.9%). Malocclusion prevalence rose from 37.7% at baseline to 48.2% at follow-up, with increases in anterior open bite (14.1% → higher) and posterior crossbite (12.7% → higher).

Persistent thumb/finger sucking beyond age 4 strongly predicted anterior open bite (OR = 4.21; 95% CI: 2.10–8.44), while pacifier use past age 3 was linked to posterior crossbite (OR = 3.58; 95% CI: 1.82–7.04). Mouth breathing correlated with narrow maxilla and increased overjet; tongue thrusting with persistent anterior open bite. Duration and frequency of habits were better predictors of malocclusion severity than habit type, with marked effects after 36 months of continuous habit expression [Tables 1 and 2].

Table 1.

Baseline distribution of oral habits and malocclusion types in the study cohort (n=220)

Oral habit		Prevalence (%)		Most common associated malocclusion		Malocclusion prevalence (%)
Pacifier use		41.4		Posterior crossbite		12.7
Thumb/finger sucking		29.1		Anterior open bite		14.1
Mouth breathing		18.6		Increased overjet, narrow maxilla		7.3
Tongue thrusting		10.9		Anterior open bite		5.9

Table 2.

Association between persistent oral habits (>3 years) and malocclusion development at the 24-month follow-up

Oral habit		OR (95% CI) for associated malocclusion		P
Thumb/finger sucking		4.21 (2.10–8.44) – Anterior open bite		<0.001
Pacifier use		3.58 (1.82–7.04) – Posterior crossbite		<0.001
Mouth breathing		2.94 (1.36–6.34) – Narrow maxilla, overjet		0.005
Tongue thrusting		3.11 (1.21–7.99) – Anterior open bite		0.018

DISCUSSION

Strong evidence that prolonged early oral habits significantly contribute to the development and progression of malocclusions is provided by this longitudinal pediatric–orthodontic study. The prevalence of malocclusion rose from 37.7% to 48.2% during the 2-year follow-up, with anterior open bite and posterior crossbite being the most common presentations. Particular correlations were found: using a pacifier after the age of 3 was significantly associated with posterior crossbite, whereas thumb or finger sucking after the age of 4 was strongly associated with anterior open bite. Increased overjet and decreased maxillary arch width were associated with mouth breathing, while persistent anterior open bite was associated with tongue thrusting.[5,6,7,8]

These results are consistent with well-established orthodontic theories that explain how long-term, low-intensity forces can upset the balance between the developing skeletal structures and the oral musculature. These forces cause changes in the skeleton and dentoalveoli by changing growth trajectories. One important consideration is the idea of a threshold duration, which is roughly 36 months; after this time, the probability and severity of malocclusion significantly rise. This is in line with past research that found a correlation between long-standing habits and proclination of anterior teeth, delayed vertical eruption of incisors, and maxillary skeletal narrowing.[6,7,8,9]

Crucially, the findings suggest that a habit’s frequency and duration have a greater impact on its severity than the habit’s type. Even small habits can gradually change craniofacial morphology and occlusal relationships if they are repeated and persistent. Clinically, identifying these behaviors early on—ideally before the child is 3 or 4 years old—offers the best chance for natural correction and lessens the need for more involved orthodontic procedures later in life. If voluntary cessation fails, management strategies may include referral to an otolaryngologist to address airway obstructions causing mouth breathing, myofunctional therapy to retrain tongue posture and oral muscle function, and habit-breaking appliances. Since many carers underestimate the long-term dental impact of behaviors like dummy use, parental counselling is also essential.[5,6,7,8,9]

These findings have significant public health ramifications that go beyond individual clinical care. The damage that prolonged non-nutritive oral habits can cause is still unknown to many families. Raising awareness of the importance of early intervention can be accomplished through educational campaigns incorporated into pediatric and dental visits. Preventive programs should be culturally sensitive and customized to the communities they are intended to serve, as cultural norms and parental attitudes frequently impact the persistence of habits.[9]

Compared with cross-sectional methods, this study’s prospective design allows for stronger causal inferences. In addition, it uses calibrated examiners and standardized diagnostic criteria to ensure dependable data collection. Limitations, however, include the limited geographic diversity of the sample, which may limit the findings’ generalizability, and the reliance on carer reporting for habit duration and frequency, which may be prone to recall bias. In order to increase data accuracy, future studies should look into using objective, digital habit-tracking techniques and larger, multicenter samples.

CONCLUSION

Prolonged early oral habits—thumb/finger sucking, dummy use, mouth breathing, and tongue thrusting—significantly increase malocclusion risk, especially anterior open bite and posterior crossbite. Severity is driven more by habit duration and frequency than type. Early detection and stopping habits before age 3–4 can help maintain normal growth and reduce future orthodontic needs.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.