Jawbone cavitations have been described for decades under various terminologies, including neuralgia-inducing cavitational osteonecrosis (NICO) and fatty degenerative osteolysis of the jawbone (FDOJ). Their biological nature and clinical relevance remain controversial. The present review aimed to summarize the current understanding of jawbone cavitations, identify relevant research gaps, and propose a unified descriptive terminology. This narrative literature review was conducted using PubMed/MEDLINE, Google Scholar, and manual searches of relevant journals. The available evidence was qualitatively synthesized. The results indicate that most published data on jawbone cavitations are derived from observational, retrospective, and cohort studies, with etiological concepts largely based on histopathological findings. Recent three-dimensional radiological analyses suggest that intraosseous non-mineralized areas frequently observed at former extraction sites may represent a physiological outcome of socket collapse and incomplete ossification rather than a pathological condition. This review introduces Covered Socket Residuum (CSR) as a radiological descriptive term and clearly distinguishes it from pathological entities such as NICO and FDOJ. Recognition of CSR is clinically relevant, particularly in dental implant planning, where unrecognized non-mineralized areas may compromise primary stability. The findings emphasize the role of three-dimensional radiological assessment for diagnosis and implant planning and discuss preventive and therapeutic strategies, including Guided Open Wound Healing (GOWH^TM). Prospective controlled clinical studies are required to validate this concept and determine its clinical relevance.

Background/Objectives: After tooth removal the crest may close before the socket has mineralised, leaving a covered socket residuum (CSR). Third molars are usually removed in young patients, often prophylactically. We examined what former third molar sites contain years later. Methods: Retrospective single-centre study of bone removed at revision of a radiologically diagnosed CSR at former third molar sites, consisting of the bone lid covering the residuum and, where labelled separately, tissue from its depth. For every section the routine pathology report was coded for a leading finding, and the cells were classified independently by whole-slide AI analysis without knowledge of the report. Results: Eighty-three sections from 28 patients (median age 54 years) were analysed. Fifty-one (61.4%) carried a distinguishing finding (53.0% without haematopoietically active marrow), most often marrow fibrosis (14.5%), granulocytic inflammation or osteomyelitis (13.3%) and lymphoplasmacytic infiltrate (10.8%). Of 24 patients with more than one section, 13 showed different findings in different sections. Fibroblasts and inflammatory cells were inversely related (r = −0.979), and the diagnoses formed a gradient from fibroblast-rich avital bone and unremarkable marrow to lymphocyte-rich inflammation (Holm-adjusted p ≤ 0.0065 for fibroblasts, lymphocytes and neutrophils). Conclusions: In this cohort, more than half of the sections from former third molar sites were histopathologically altered, with findings that varied within the same patient. Third molar removal is bone surgery requiring asepsis, removal of the follicle and debridement of the socket, and filling the socket to prevent a residuum deserves controlled evaluation.

Background/Objectives: After extraction, the crest may close before the socket has mineralised, leaving a covered socket residuum that may enclose the tissue lining the socket. We examined the socket wall histologically at the moment of extraction and compared it with the periapical region and the socket walls on preoperative cone-beam computed tomography (CBCT). Methods: Retrospective single-centre study of teeth extracted by one surgeon for a clinical indication in routine care. Before decortication according to the ARENA-Protocol^® (Alveolar Ridge Epithelialization after Non-viable Bone Debridement and Augmentation), a trephine core was taken along the long axis of the socket wall; soft tissue was submitted when present. Each specimen received a leading diagnosis from a predefined hierarchy. Results: Sixty-six specimens from 41 sockets in 23 patients were examined. Thirty-eight sockets (92.7%) were altered. Bone showed mainly chronic inflammation and marrow fibrosis, soft tissue mainly florid inflammation. The radiographic lesion lay periapically and was visible on CBCT and its three-dimensional visualisation, whereas the lateral wall from which the core was taken showed no distinct change on either and was nevertheless altered, also in all three sockets without a periapical finding. All 14 root-filled and 24 of 27 non-root-filled sockets were altered. Conclusions: In this cohort, the socket wall was altered at extraction in almost every case, and the alteration along the long axis of the socket was detected only histologically. If the crest closes over such a wall, a residuum may enclose altered tissue. Controlled studies are needed to test this.