Management of Posterior Mandibular Bone Cavitation for Dental Implant Placement: A Case Series of 5–24 Years of Follow-Up
Focal osteo-cavitation in the posterior mandible is a condition that clinicians do not know well. Inadvertent implant placement in such areas may result in nerve damage due to abrupt drill penetration and implant displacement in the medullary space. In the present case series, focal osteo-cavitation was managed with the following procedures: (1) undersized drilling, (2) gentle trabecular curettage, (3) bone substitute material grafting in the cavity, and (4) long healing period for osseointegration. In all cases, a sudden loss of drilling pressure immediately after passing through the thin cortical layer revealed focal osteo-cavitation. Following undersized drilling and gentle trabecular curettage, the bone substitute material was packed into the cavity with care not to press the inferior alveolar canal. Implant placement was subsequently performed. Despite a lack of primary implant stability in 3 of 4 cases, all implants were successfully osseointegrated after 6–9 months. Over 5–24 years, all implants functioned well.
Case 1. (a) Preoperative clinical situation of the #31 and #30 sites. (b) Focal osteo-cavitation was found on the #31 site. (c) The cavity defect was filled with bone substitute material. (d) An implant was placed, but primary stability was not fully achieved. (e) A collagen barrier was applied. (f) Primary closure was performed. (g) Slight radiolucency was observed on the distal area of the #31 site, but it was hard to expect focal osteo-cavitation in the preoperative panoramic radiograph. (h) Slight increase of radiopacity was found on the #31 site immediately after implant placement. (i) After 5 years, radiopacity is more distinct on the #31 site than before. (j and i) In the cone beam computed tomographic images at 5 years, bone grafting area was clearly seen, and the stable marginal bone level was observed. Arrowheads indicate focal osteo-cavitation. Arrows indicate the bone substitute material-grafted area. Figures (g–i) are cropped images from the original panoramic radiographic images.
Case 2. (a) Focal osteo-cavitation was found on the #31 site. (b) After gentle packing of bone substitute material on the #31 site, 2 implants were placed on the #30 and #31 sites. (c) Slight radiolucency was observed, but it was hard to expect focal osteo-cavitation on the #31 site on the preoperative panoramic radiograph. The radiolucency of the #30 sites looked greater compared with the #31 site. (d) An increase of radiopacity was found on the #31 site immediately after implant placement due to bone graft material insertion. (e) An panoramic image after 9 months. (f) After 24 years, bone grafting area is still distinct from the adjacent area in the panoramic radiographic image. (g and h) In the cone beam computed tomographic images at 24 years, bone grafting area was clearly seen, and the stable marginal bone level was observed. Arrowheads indicate focal osteo-cavitation. Arrows indicate the bone substitute material-grafted area. Figures (c–f) are cropped images from the original panoramic radiographic images.
Case 3. (a) Slight radiolucency was observed on the #31 site, but it was hard to expect a focal osteo-cavitation site in the preoperative panoramic radiograph. The #29 tooth needed to be extracted due to a periapical lesion. (b) On the #31 site, bone substitute material was gently packed, and an implant was subsequently placed. (c) After 17 years, the bone substitute material-grafted area was demarcated with the adjacent area in the panoramic radiographic image. (d and e) In the cone beam computed tomographic images at 17 years, bone grafting area was clearly seen, and the stable marginal bone level was observed. Arrows indicate the bone substitute material-grafted area. Figures (a–c) are cropped images from the original panoramic radiographic images.
Case 4. (a) The #30 and #31 teeth had been extracted 10 years before. Localized osteoporosity was observed on both sites in the preoperative panoramic radiograph. (b) On the #31 site, focal osteo-cavitation was found. On that site, bone substitute material was gently packed, followed by implant placement with primary stability. (c) In the panoramic radiographic image at 18 years, bone grafting area was clearly observed on the #31 site. (d and f) In the cone beam computed tomographic images at 18 years, bone grafting area was demarcated with the neighboring area, and stable marginal bone level of the #31 implant was observed. Arrows indicate the bone substitute material-grafted area. Figures (a–c) are cropped images from the original panoramic radiographic images.
Contributor Notes