Modified difficult index adding extremely difficult for fully impacted mandibular third molar extraction

Abstract

Objectives: The aim of this study was to evaluate the validity of the existing classification and difficulty index of impacted mandibular third molars in clinical situations and propose a more practical classification system. Materials and Methods: This study included 204 impacted mandibular third molars in 154 patients; panoramic x-ray images were obtained before tooth extraction. Factors including age, sex, and pattern of impaction were investigated. All impacted third molars were classified and scored for spatial relationship (1-5 points), depth (1-4 points), and ramus relationship (1-3 points). All variables were measured twice by the same observer at a minimum interval of one month. Finally, the difficulty index was defined based on the total points scored as slightly difficult (3-4 points), moderately difficult (5-7 points), very difficult (8-10 points), and extremely difficult (11-12 points). Results: The strength of agreement of the total points scored and difficulty index were 0.855 and 0.746, respectively. Most cases were classified as moderately difficult (73.0%). Although only 13 out of 204 cases (6.4%) were classified as extremely difficult, patients classified as extremely difficult were the oldest (P<0.05). Conclusion: For difficulty classification, the authors propose one more difficult category beyond the existing three-step difficulty index: the clinician should consider the patient's age in the difficulty index evaluation.

Development and validation of a difficulty index for mandibular third molars with extraction time

“…Two findings were revealed in this study. First, the difficulty index 5 classified as grades I, II, and III based on CT data reformatted to a panoramic view was correlated with extraction time of impacted third molars other than grade IV. Second, the modified difficulty indices that considered the presence of pathologic conditions were strongly correlated with extraction time.…”

“…Prediction of surgical extraction difficulty is important for anticipating postoperative issues and planning treatment options such as general anesthesia in a controlled environment to prevent complications 12 , 13 . Extraction difficulties were evaluated based on position of the third molars using panoramic radiography 1 - 5 . The position was associated with postoperative complications such as alveolar nerve injury 6 and dry socket 7 .…”

“…In addition, the modified difficulty score was calculated by adding one point to the difficulty score if the third molar was associated with a pathologic condition. Two modified difficulty indices that considered the presence of pathologic conditions were defined as follows: the half-level up difficulty index (HDI) and the one-level up difficulty index (ODI) based on the difficulty index reported by Kim et al 5 .…”

“…Since the 19th century, several researchers have attempted to classify extraction difficulty using radiographic techniques or estimating the prevalence of complications 1 - 5 . In December 2019, a difficulty index was proposed based on positional variations in impacted mandibular third molars evaluated by panoramic radiography 5 . The position of the third molar is associated not only with postoperative complications, but also surgical difficulty and operation time 6 , 7 .…”

“…Impacted third molars may be associated with pathologic conditions such as root resorption of the adjacent tooth, pericoronitis, dentigerous cysts, and benign neoplasms 11 . However, few studies have evaluated the presence of pathologic conditions even though they are more frequently encountered than complications 5 .…”