DCA03TM Third Molar Surgery, 5th Edition _____________________________________________________
FULL BONE IMPACTION With full bone impaction, the third molar crown is completely (or mostly) below the alveolar crest and encased in the bone. During surgical removal, exposure of the whole tooth is often needed in order to elevate it. The beginning of the procedure is the same as for a partial bone impaction with a buccal flap and a buccal trough. At this point the crown is sectioned from the roots with a surgical bur. Mesiobuccal (mesioangular), distobuccal (distoangular), or horizontal full-bone impactions usually require sectioning the crown off the roots in order to expose and then elevate the roots. A careful vertical sectioning of the crown is performed, paying attention to the protection of the lingual soft tissue. At this time exposed roots can either be elevated or separated and elevated one by one, as needed. A bone file is used to smooth the bone edges; the socket is examined for bleeding, remnants of roots, bone wall integrity, and soft tissue condition around the socket, and finally it is closed with sutures (Muhsin and Brizuela, 2023). Granulomatous (chronically inflamed) tissue that is present within the extraction socket is removed at the end of the surgery with a curette. If granulomatous tissue is proximate to the IAN, the LN, or the maxillary sinus, clinicians must use their judgment in its removal to prevent iatrogenic damage to these structures. It is important to carefully separate the granulomatous tissue from the lingual tissue to prevent trauma to the LN. All the incisions of the soft tissue, removal of bone by a rotary instrument (bur), and crown sectioning should be done on the buccal side to prevent the previously described LN injury. Knowledge of surgical anatomy is important to prevent surgical complications. Clinicians have the option to use a bite block during surgery to minimize the postoperative development of temporoman- dibular joint symptoms. A throat pack prevents the displace- ment of the tooth or its pieces into the bronchial tree or the gastrointestinal tract (Zhao et al., 2023. A throat pack/throat screen must be used in a judicious fashion and monitored to prevent accidental aspiration, especially among patients who are sedated. Postoperative instructions are given to the patient, and a follow-up appointment is scheduled for one week after the surgery. Intentional partial odontectomy (coronectomy) is an alterna- tive that is not commonly known or employed for the manage- ment of complicated lower third molars in the U.S. (Lamiae et al., 2022). ). This procedure provides an alternative mode of treatment to a traditional surgical extraction of an impacted third molar in close proximity to the IAN with a high potential for surgically induced IAN injury. This technique involves exposing the impacted tooth, sectioning the entire crown off the roots, removing the granulomatous tissue (debridement) and the entire crown, and closing the wound, leaving the roots in situ. This approach eliminates the crown of the impacted tooth, whose protrusion through the tissue can cause problems
An erupted third molar can often be removed in the same manner as any molar, using an elevator and/or extraction forceps. A deep coronal caries extending to the root surface, history of root canal treatment, root ankylosis, or hypercemen- tosis complicates the procedure and may require an envelope flap and even bone removal. Root ankylosis is the loss of the periodontal ligament and the subsequent fusion of the root to the bone. Hypercementosis involves the formation of globular areas of cementum at the root apices, which impede the path of withdrawal of the tooth from the bone. The presence of ankylosis or hypercementosis, or both, will further complicate the extraction of an impacted wisdom tooth (Muhsin and Brizuela, 2023). The globular formations at the root apices that characterize hypercementosis impede the path of with- drawal of the tooth from the bone. Extracting a tooth requires separation of the periodontal ligament from the tooth. An ankylosed tooth has a rigid continuum with the alveolar bone that promotes its retention within the socket that is devoid of the periodontal ligament. SOFT TISSUE IMPACTION In cases of soft tissue impaction, the third molar crown is slightly below the occlusal plane but above the alveolar crest. The crown is partially covered with retromolar soft tissue. During surgical removal, the initial incision is made at the ascending ramus at the external oblique ridge and continues anteriorly to the distobuccal corner of the second molar, where it becomes a sulcular incision to the mesiobuccal corner of the tooth. This provides complete exposure of the crown (Materni et al, 2021). A vertical releasing incision is then made from the mesiobuccal corner of the second molar and is extended to the depth of the vestibule. This is often referred to as a hockey stick incision because of its shape. A periosteal elevator is then used to reflect a buccal full-thickness flap. An exposed tooth can be elevated with a straight elevator (an alternative is the 77R elevator) and extracted with universal lower forceps. The socket is gently curetted and irrigated with a sterile normal saline solution. An optional 3-0 gut suture can be placed to approximate the flap. PARTIAL BONE IMPACTION In the case of partial bone impaction, the third molar crown is partially above the alveolar crest and partially below it and is surrounded by the alveolar bone in the retromolar region. During surgical removal, complete exposure of the crown is achieved using the same process as that described for soft tissue impactions. The buccal trough is usually made with a surgical bur to expose the submerged part of the crown and coronal aspects of the roots of the impacted third molar (Choi et .al, 2025; Muhsin and Brizuela, 2023). An exposed tooth can then be raised with a straight elevator. The socket is curet- ted and irrigated with a sterile normal saline solution. A 3-0 gut (resorbable) suture or a black silk suture can be placed to approximate the flap.
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