Age-related prevalence and correlation of dental and periodontal lesions in second molars adjacent to mesioangular and horizontally impacted mandibular third molars: a CBCT study.

BACKGROUND

The management of asymptomatic impacted mandibular third molars (MTMs) remains controversial, particularly due to variations in impaction types and their associated risks. Mesioangular and horizontal impactions are common, yet their effects on adjacent mandibular second molars (MSMs) have not been thoroughly investigated. Clarifying the prevalence and severity of related pathologies and their correlation with age is crucial for clinical decision-making. This study aims to provide epidemiological evidence to support the management of mesioangular and horizontal MTMs.

METHODS

This study was a retrospective and cross-sectional observational study. CBCT data of 875 pairs of mesioangular and horizontal impacted MTMs and their adjacent MSMs in 643 patients were collected and evaluated by two observers. Prevalence of caries, external root resorption (ERR) and bone loss (BL) of MSMs, percentages of the severity of lesions and their correlations with patient age were calculated. The chi-square test was used to analyze the difference between each impaction group. Spearman rank correlation analysis was applied to analysis the correlations.

RESULTS

In all MSMs, the overall prevalence of caries, ERR and BL of MSMs were 20.91%, 15.09%, 27.66% respectively. The overall prevalence of caries, ERR, and BL of MSMs were 27.80%, 14.41% and 35.08% in mesioangular impact group and 6.67%, 16.49% and 12.28% in horizontal impact group. A significant positive correlation was observed between age and the prevalence of caries and BL in the mesioangular impaction group (p < 0.001), whereas age was positively correlated with the prevalence of ERR in the horizontal impaction group (p < 0.001).The severity of caries, BL and ERR were positively correlated with patient age in mesioangular impact group (p < 0.01). The severity of caries and BL were positively correlated with patient age in horizontal impact group (p < 0.05).

CONCLUSIONS

Mesioangular impacted MTMs are more likely to cause caries and BL in adjacent teeth compared to horizontal impacted MTMs, whereas horizontal impacted MTMs tend to result in more severe ERR. Age plays a significant role in the occurrence and development of these diseases.