Multivariable Analysis of Correlation Between Anatomical Features of Mandibular Third Molars and Pericoronitis

Abstract

Objective: The correlation between anatomy features of impacted mandibular third molars (M3Ms) and prevalence of pericoronitis was only interpreted using univariate analysis. This study investigated this correlation using multivariable analysis to determine the relationship between pericoronitis prevalence and the M3Ms' anatomical features. Methods: This cross-sectional study recruited 245 patients with 338 impacted M3Ms. One researcher collected participants' demographic characteristics such as sexes, age, side, and pericoronitis condition. The radiographic characteristics of M3Ms, including eruption direction and impacted levels according to Pell-Gregory classification, were assessed based on their orthopantomograms. Initially, univariate analyses were used to determine potential demographic and radiographic factors that correlated to pericoronitis. These factors were, then, analyzes using Firth's logistic regression. Results: No significant difference was found between non- and pericoronitis groups about sexes, age, side (p > 0.05). The univariate analyses showed that proportion of vertical impacted levels and eruption direction of M3Ms were significantly different between non- and pericoronitis groups. Firth's logistic regression analysis indicated that M3Ms with impacted level A were more likely to suffer from pericoronitis than ones at level B (odds ratio (OR) = 3.34), wheraes M3Ms impacted level II had higher risk of pericorinitis than ones at level I (OR = 1.63). Vertical M3Ms were more likely to develop pericoronitis than horizontal (OR = 5.78) ones. Conclusion: M3M angulation and impacted level are significant factors relating to pericoronitis prevalence. M3Ms with vertical eruption, vertically level A, and horizontally level B are more likely to have pericoronitis.

Keywords: Pell–Gregory classification; mandibular third molar; pericoronitis; risk factors; winter classification.

Figure 1

Proportion of M3Ms with and without pericoronitis according to angulation types and Pell–Gregory classification. M3M, mandibular third molar.

Figure 2

Illustration of different M3M angulation types with the same Pell–Gregory classification (IA) and distal operculum. (A) Vertical, (B) mesioangular, (C) horizontal, and (D) distoangular. Although the four M3M types have the same Pell–Gregory classification, vertical and distoangular teeth are more likely to have an operculum covering the crown. M3M, mandibular third molar.