Previous studies have suggested that masticatory forces are associated with cracked
teeth, but it is not clear which specific poor oral masticatory habits may be more
likely to cause cracks. The aim of this study was to quantitatively assess risk factors
for cracked teeth among poor oral masticatory habits and create a model for individualized
We enrolled 35 patients with cracked teeth matched to 70 controls without cracked
teeth by age, sex, position of the affected tooth, presence/absence of systemic disease,
and diagnosis of symptomatic irreversible pulpitis from the Stomatology Hospital of
Tianjin Medical University, Tianjin, China. Odds ratios (ORs) were calculated using
conditional logistic regression analysis.
Thermal cycling eating habits (OR = 3.296; 95% confidence interval [CI], 1.684−6.450),
eating coarse foods (OR = 2.727; 95% CI, 1.340−5.548), chewing on hard objects (OR
= 2.087; 95% CI, 1.041−4.182), and unilateral mastication (OR = 2.472; 95% CI, 1.255−4.869)
were independent risk factors for cracked teeth. The corresponding risk scores were
2.182, 1.691, 1.467, and 1.589, respectively. The area under the receiver operating
characteristic curve and its 95% CI were 0.920 (0.868−0.973); the sensitivity and
specificity were 0.943 and 0.800, respectively.
Thermal cycling eating habits were strongly associated with cracked teeth, whereas
eating coarse foods, chewing on hard objects, and unilateral mastication were also
independent risk factors for cracked teeth. These findings yield insights into ways
to promote the prevention of risky behaviors for cracked teeth.