Radiographic assessment of distribution of mandibular third molar impaction: A retrospective study

Bilateral Inverted and Impacted Mandibular Third Molars: A Rare Case Report

Even while certain forms of mandibular impactions (such as inverted molars) might be considered unusual findings, mandibular impacted teeth are really one of the most regularly seen dental abnormalities. Two female patients' mandibular third molars were discovered to be inverted during a regular inspection, and two such examples are reported here in this article. Both patients underwent routine radiographic examination. Cone beam computed tomography and orthopantomogram were requested to evaluate the state of the bone and to check for any abnormalities, and inverted impacted teeth were discovered. A tooth is said to be inversed when it is placed reversed and seated upside down. Ascending ramus is the most common site for third molars in the mandible. It is also possible for a maxillary tooth to get impacted and for the tooth to be pushed all the way to the orbit's floor, though mandibular impacted teeth are more common. Only a few cases of inverted and impacted mandibular third molars have been reported in the literature. No definitive treatment protocols exist for the removal of inverted teeth. The safest protocol is conservative treatment in which the teeth are not extracted until they produce pathological signs.

Evaluation of Third Molar Impaction Distribution and Patterns in a Sample of Lebanese Population

BACKGROUND

Classifications of impaction based on panoramic radiographs such as the ones of Pell and Gregory and Winter are essential to allow a better understanding of third molar position regarding depth and bone coverage of the impacted tooth and to evaluate the difficulties of the surgical procedures. The aim of the study was to classify upper and lower third molars teeth in a sample of a Lebanese population and compare the data to results from other studies.

MATERIALS AND METHODS

Digital panoramic radiographs of 71 patients with a total of 181 wisdom teeth from patients that had been subjected for third molars extraction, from November 2016 to November 2018, were collected and analyzed. The mean age was 26.25 years. All third molars were categorized according to Pell and Gregory by using A, B, C scores for depth in upper and lower third molars, and angulations were classified according to Winter's classification. Nonparametric normality tests evaluating age group and gender distribution were conducted by utilizing the Chi-square test for age distribution and the binomial and Kruskal-Wallis tests for gender.

RESULTS

In the Pell and Gregory classification, the lower third molars showed type B impaction as the most frequent with 66.1% for the right side and 60.3% for the left side; the maxillary third molars both showed the type C impaction as the most frequent with 63.3% for the right side and 59.2% for the left side. According to the Winter classification, lower third molars showed mesio-angulation as the most frequent angle of impaction with 41.1% for right mandibular side and 46.5% for mandibular left side; As for the maxillary third molars, the disto-angulation was the most frequent angulation seen in both maxillary right and left side teeth 53.3% and 43.2%.

CONCLUSIONS

Comparison of our results with other populations has shown similarities in certain criteria like angulation and relation to ramus, but most results varied. Thus, the current study can be taken as a baseline for further studies.

The Pattern of Mandibular Third Molar Impaction and Assessment of Surgery Difficulty: A Retrospective Study of Radiographs in East Baltic Population

Classifications of impacted teeth allow defining the type and degree of retention, as well as assessing the degree of difficulty of the procedure. The aim of this study was to conduct retrospective analysis of the degree of retention and difficulty in the surgical removal of impacted mandibular third molars in the clinical material of the Department of Oral Surgery in 2013–2018. This study included 1585 dental panoramic radiographs of patients of the Department of Oral Surgery, who reported in 2013–2018, in order to perform surgical removal of the impacted mandibular third molar. Based on dental panoramic radiographs, the degree of retention was determined based on classifications according to Winter, according to Pell and Gregory, according to Tetsch and Wagner, and according to Asanami and Kasazaki. The difficulty of the procedure was also assessed based on the Pederson index. The most common types of lower wisdom tooth impaction are as follows: in Winter’s classification, mesial-angular impaction; in Tetsch and Wagner’s classification, oblique medial-angular impaction; in Pell and Gregory’s classification, impaction grade 2A; and in Asanami and Kasazaki’s classification, 3A and anterior inclination. In most cases of surgical removal of an impacted tooth, the anticipated difficulty of the procedure was rated as very difficult.

Three-dimensional measurement and analysis of mandibular characteristics in subjects with impacted mandibular second molars

OBJECTIVE

To investigate the morphological characteristics of the mandible in subjects with impacted mandibular second molars by measuring and analysing the mandible in three dimensions.

SETTING AND SAMPLE POPULATION

In this retrospective study, the data of a total of 52 609 subjects who underwent cone-beam computed tomography (CBCT) for diagnosis and treatment were reviewed. According to the inclusion and exclusion criteria, 183 subjects with impacted mandibular second molars and 176 age- and sex-matched controls were included.

METHODS

A retrospective case-control study was designed. The 183 subjects were divided into two groups: group 1 (G1) comprised 120 patients with unilaterally impacted mandibular second molars, and group 2 (G2) comprised 63 patients with bilaterally impacted mandibular second molars. Group 3 (G3) contained 176 age- and sex-matched controls. The mandible was reconstructed with nineteen landmarks using Mimics software. Twelve linear lengths and 3 angles were measured.

RESULTS

The bilateral germination gap, mandibular body width and gonion width in G1 were significantly lower than those in G3 (P < .05), while the gnathion angle and first molar width values in G1 were significantly higher than those in G3 (P < .05). The results in G2 were similar to those in G1, but the differences between G2 and G3 were greater than those between G1 and G3. There were no significant differences in the other measurements among the groups.

CONCLUSION

The mandibles of the subjects with impacted second molars were constricted in terms of the sagittal length and transverse width.