Cervical flexor muscle performance and craniovertebral posture in adolescents with vertical occlusal anomalies: a...

This study aimed to investigate whether vertical occlusal anomalies are associated with deep cervical flexor endurance (DCFE), cervical flexor strength (CFS), and craniovertebral angle (CVA).

Sixty-two adolescents (mean age: 12.8 ± 1.5 years) were included in this cross-sectional study and allocated to a vertical occlusal anomaly group (VOAG, n = 31) or a control group without vertical anomalies (NVOAG, n = 31). DCFE, CFS, and CVA were assessed using standardized clinical methods. Between-group comparisons were performed, and analysis of covariance (ANCOVA) was used to adjust for age, sex, and body weight.

DCFE was significantly lower in the VOAG compared with the NVOAG (17.1 ± 6.9 s vs. 22.2 ± 7.8 s; p = 0.009), representing an approximate 23% reduction and a medium effect size (Cohen's d = - 0.68). No significant between-group differences were observed for CFS (p = 0.379) or CVA (p = 0.190). DCFE was positively correlated with age, body weight, and sex (all p < 0.05). After adjustment for covariates, vertical occlusal anomaly status remained independently associated with DCFE (F(1,57) = 8.18, p = 0.006, partial η² = 0.127).

Vertical occlusal anomalies are associated with reduced DCFE in adolescents, independent of growth-related factors. This association appears to be specific to endurance capacity, as cervical strength and head posture were not affected. Further studies are needed to determine the clinical significance of this finding.

Assessment of cervical muscle endurance may provide additional functional insight in adolescents with vertical occlusal anomalies and support interdisciplinary evaluation in orthodontic practice. Although statistically significant, the clinical relevance of this approximately 5-second difference remains uncertain, as no minimal clinically important difference has been established for DCFE.