To evaluate the associations of impaction patterns of mandibular third molars (M3Ms) with pathologies caused by them. In this study, 262 patients with 432 impacted M3Ms who referred in Shanghai Xuhui District Center were reviewed. The pathologies include pericoronitis, mandibular second molar (M2M) caries, and M2M distal periodontal pathology. The impaction patterns of M3Ms and the pathologies were examined, while the M2M outcomes after surgeries were evaluated. A χ2 test was used to analyze the data, with a p value of <0.05 being considered statistically significant. Pericoronitis was the major symptom in all patients, whereas the propensities of M2M distal caries and periodontal pathologies increased in older patients. Soft tissue impacted and vertically angulated teeth were more associated with pericoronitis ( p < 0.05); mesio-angular impacted teeth in less deep positions had greater risks of M2Ms distal caries ( p < 0.05); mesio-angular and horizontal impacted teeth in relative deep positions were more likely to cause M2Ms distal periodontal pathologies ( p < 0.05). Extractions of soft tissue impacted teeth in vertical angulations should be considered, while removals of mesially and horizontally angulated or bony impacted teeth could be delayed.

The juxta-articular myxoma represents a benign mesenchymal neoplasm that arises from tissue within or adjacent to a joint space. There have been a number of reported cases involving myxomas of the knee, shoulder, elbow, wrist, and hip. To our knowledge there, however, have been no reported cases of juxta-articular myxomas of the temporomandibular joint (TMJ). This report describes the case of a 57-year-old woman with a juxta-articular myxoma of the left TMJ extending into the infratemporal fossa (ITF). Access to the tumor was accomplished via a preauricular incision and low condylar osteotomy which allowed for displacement of the condyle for direct visualization and excision of the tumor. The postoperative course was benign and the patient demonstrated no cosmetic or functional limitation. Likewise, follow-up at 30 months showed no evidence of recurrence. Benign encapsulated tumors of the ITF can be effectively accessed by means of a modified preauricular incision, low condylar osteotomy, and anterior meniscal release. This direct approach allows for excellent surgical exposure, minimal surgical site morbidity, and maintenance of physiologic joint function and occlusion.

Extracting horizontal mandibular 3rd molars face considerable difficulty due to the large bone and adjacent tooth resistances. This study aims at evaluating the effectiveness of a novel method-mesiolingual root rotation to extract wisdom teeth of this type. In this study, 73 horizontal teeth extracted using piezosurgery were reviewed and classified based on impaction depth: position I, II, III refers to the highest portion of the crown on a level with upper 1/3, middle 1/3, lower 1/3 of the 2rd molar’s root. Based on the surgical simulations on their 3D CBCT reconstructions, traditional method(crown distal rotation) and novel method(root mesiolingual rotation) are applied. 79.17% of teeth in position I and 57.89% of teeth in position II were designed using traditional method, 83.33% teeth in position III were designed using the novel method(p < 0.05). The surgeries were performed according to the designs. Two cases in position II using traditional method were found temporary inferior alveolar nerve(IAN) injury; while only one case in position III using novel method got temporary IAN and lingual nerve injury. Our study suggested that root mesiolingual rotation is an effective method to extract the horizontal mandibular 3rd molars, especially the deep impacted ones.