The extraction of impacted lower third molars (ILTM) is one of the most common procedures in oral-maxillofacial surgery. Being adjacent to lower second molars, most impacted lower third molars often lead to distal periodontal defects of adjacent second molars. Several symptoms may occur after extraction, such as periodontal pocket formation, loss of attachment, alveolar bone loss and even looseness of second molar resulting in extraction. The distal periodontal defects of second molars are affected by many factors, including periodontal conditions, age, impacted type of third molars, and intraoperative operations. At present, several studies have suggested that dentists can reduce the risk of periodontal defects of the second molar after ILTM extraction through preoperative evaluation, reasonable selection of flap design, extraction instruments and suture type, and necessary postoperative interventions. This review summarizes the research progress on the influence factors, interventions methods and some limitations of distal periodontal defects of adjacent second molar after extraction of impacted mandibular third molars, with the aim of opening up future directions for studying effects of ILTM extraction on periodontal tissue of the adjacent second molar.

Background As the potential risks of the development of the adjacent incisors and jaws, mesiodens, especially inverted mesiodens, should be prophylactically extracted in mixed or early permanent dentition. However, because of the limit of small clinical data, there is relatively inadequate and lacks systematic, comprehensive understanding on minimizing operation injury for high inverted mesiodens. The aim of this study is to provide reliable support for the choice of extraction of high inverted mesiodens, and minimize the operation injury for patients.Methods Thirty patients were randomly divided into three groups according to three different surgical designs in the extraction of high inverted mesiodens. The operation statistics, life quality of postoperative patients, and the operative injury/recovery were compared and analyzed. The laser Doppler blood flowmetry, laser speckle contrast imaging, and electric pulp testing were explored to detect the postoperative pulp and gingiva blood supply of adjacent teeth.Results For the clinician's primary concerns, the surgical time, the volume of osteotomy, and the amount of bleeding in the labial approach group and intranasal approach group were significantly less than that in the palatal approach group (p<0.05). However, from the patient's perspective, the postoperative swelling and pain in the labial approach were far more than that in the intranasal approach group (p<0.05), with unsurprisingly lower satisfaction (p<0.05). Under excellent surgical operation，there were no significant differences in pulp and gingival blood supply of adjacent teeth and jaw development (p>0.05).Trauma was manageable in all patients.Conclusions With precisive operation, maxillary inverted impacted mesiodens could be extracted by three methods, and the controlled trauma would not affect the development of teeth and jaw. Under the inclusion and exclusion criteria of this study, the extraction of mesiodens by the intranasal approach achieved a delicate balance between reducing surgical trauma and optimizing postoperative recovery, which was of concern and merited further study.Trial registration The study was approved by the Ethics Committee of Shanxi Medical University School and Hospital of Stomatology (2019SLL022), and retrospectively registered at chictr.org.cn (ChiCTR2100054777). All patients provide written informed consent before participating in treatment.

No abstract

No abstract