Abstract
Background Prevalence of distal caries in mandibular second molars (M2Ms) and its relationship with impacted condition of the adjacent mandibular third molars (M3Ms) have been reported in some studies. The results, however, were ambiguous because of including all impaction types and using univariate analysis for statistics. Aim This study aimed to determine anatomical features of mesially/horizontally impacted mandibular third molars (M3Ms) that could predict distal caries in the adjacent mandibular second molars (M2Ms) using multivariable analysis. Materials and Methods The study sample consisted of 300 digital panoramic radiographs of patients who underwent impacted M3Ms extraction. Two independent researchers collected the following variables from 446 pairs of M2M-M3M: sex, age, status of distal caries in M2Ms, mesial angulation, and Pell–Gregory classification of M3Ms. Results The prevalence of distal caries was 50.67%. Multivariable Firth's logistic regression analysis showed that age (β = 0.066, 95% CI = 0.023–0.113), mesial angulation (<30°: β = −1.205, 95% CI = −1.955 to −0.499; >70°: β = −0.730, 95% CI = −1.184 to −0.282), vertical position (level B: β = 2.275; 95% CI = 0.015–7.175; level A: β = 3.008; 95% CI = 0.755–7.905), and horizontal position (level II: β = 1.515; 95% CI = 0.444–2.874; level I: β = 1.423; 95% CI = 0.283–2.825) were significant variables after adjusting for sex in the final model for predicting distal caries (p < 0.05). Conclusions In conclusion, anatomical positions of impacted M3Ms, such as mesial angulation and Pell–Gregory classification were significant predictors of distal caries in M2Ms.
Highlights
Impacted mandibular third molars (M3Ms) are a popular oral condition, with an average prevalence of 24.4% in adults [1]. ey cause numerous pathological problems in the surrounding structures, such as dental caries, periodontal pockets, pericoronitis, dental tumors, or cysts. ese lesions are usually mild symptomatic or asymptomatic, and challenging to diagnose with conventional radiographs [2, 3]
Some studies have examined the relationship between distal caries in M2Ms and impacted M3Ms
A few studies have focused on mesially/horizontally impacted M3Ms; multivariable analysis was not employed to adjust for contribution of independent factors [11, 14, 15]. e study results revealed that anatomical positions of mesially/horizontally impacted M3Ms, such as mesial angulation, and vertical and horizontal levels were significant predictors of distal caries in M2Ms
Summary
Impacted mandibular third molars (M3Ms) are a popular oral condition, with an average prevalence of 24.4% in adults [1]. ey cause numerous pathological problems in the surrounding structures, such as dental caries, periodontal pockets, pericoronitis, dental tumors, or cysts. ese lesions are usually mild symptomatic or asymptomatic, and challenging to diagnose with conventional radiographs [2, 3]. Is study aimed to determine anatomical features of the mesially/horizontally impacted M3Ms that could predict distal caries in the adjacent M2Ms, using multivariable statistical analysis. A chi-squared test was employed to test differences in the prevalence of distal caries between sexes, sides, mesial angulation, and horizontal and vertical positions of impacted M3Ms. Mann–Whitney U test was used to examine differences in age between the caries and noncaries groups. Previous studies have shown that distal caries in M2Ms is correlated with multiple factors, such as sex, mesial angulation, and Pell– Gregory classification [9, 11, 12]. Erefore, multivariable Firth’s logistic regression analysis was conducted to determine the correlation between potential factors and distal caries in M2Ms. Statistical significance was set at p value < 0.05
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