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Biomedical subjects

Ralf Schoen

Publications and source records attributed to Ralf Schoen.

8 recordsLinked to original sources
PubMed2007

Bone formation after sinus augmentation with engineered bone.

OBJECTIVES: The aim of the following investigation was to quantify the resorption rate of tissue-engineered bone grafts in the maxillary sinus using volume measurements. MATERIAL AND METHODS: Sinus floor augmentation using autologous bone grafts from the iliac crest (n=17, group 1) was compared with commercially produced transplants of human cells seeded on polyglycolid-polylactid (PLGA) scaffolds (Oral Bone) (n=14, group 2). RESULTS: The total resorption rate for autologous transplants 3 months post operation was 29%, while the tissue-engineered bone showed a resorption rate of 90%. The autologous bone had a bone density of up to 266-551 Hounsfield units (HU), while sufficient mineralization of tissue-engineered bone was found in only one case (152 HU). CONCLUSION: In this clinical study, the use of autologous cancellous bone grafts in sinus augmentation was more reliable than scaffolds containing cultured osteoblasts. Further tissue-engineered bone transplants should be examined to draw general conclusions about the use of tissue-engineered grafts compared with autologous bone grafts for maxillary sinus augmentation.

Alveolar Ridge Augmentation↗
PubMed2007

Complicated late mandibular fracture following third molar removal.

Mandibular fractures are a rare complication after third molar removal. Symptoms show a wide variance. Treatment options range from prescription of a soft diet to surgical treatment by open reduction and internal fixation. This article describes a patient who presented a late mandibular fracture following third molar removal. The fracture was not detectable in radiographs at the time of fracture. Six weeks after the reported cracking noise, the patient presented a mandibular fracture with associated osteomyelitis. Treatment by open reduction and internal fixation and autologous iliac crest graft was performed via a submandibular approach. The delayed diagnosis of this pathologic fracture demonstrates the necessity of repeated radiologic controls to prevent osteomyelitis when a fracture is suspected.

Bone Plates↗
PubMed2006

Obturator after marsupialization of a recurrence of a radicular cyst of the mandible.

The radicular cyst is the most common odontogenic cyst. We present the case of a 51-year-old man with an extended recurrence of a radicular cyst of the mandible that was treated with marsupialization. Subsequently, an obturator was fitted, and in 10 months a resolution (clinically and radiographically) of the cystic cavity was noticed without any signs of recurrence. The marsupialization is a well-established, nonaggressive treatment of large odontogenic cysts and shows advantages in preserving vital structures, with reduced risk of pathological mandibular fractures. The patient, however, must be compliant and accept the prolonged treatment of marsupialization.

Humans↗
PubMed2005

Computer-assisted reconstruction of orbital floor based on cone beam tomography.

We used a navigation system for computer-assisted preoperative planning based on cone beam tomography with virtual reconstruction to obtain symmetry of the orbit and intraoperative control of virtual contours. In operations for reconstruction of the orbital floor this technique offers a reliable intraoperative control in an area of limited exposure and visibility. There was no significant difference in visualisation of anatomical structures between the cone beam tomographic digital imaging and communication (DICOM) data and computed tomographic data. Cone beam tomography seems to be suitable for computer-assisted planning in the management of orbital trauma with reduced costs and less radiation.

Aged↗
PubMed2004

Navigation-aided reconstruction of medial orbital wall and floor contour in cranio-maxillofacial reconstruction.

The reconstruction of the anterio-posterior inclination of the medial aspect of the orbital floor, despite a wide 360 degrees exposure, including coronal and conjunctival incisions, is a challenging task in severe injuries of the orbit with massive comminution and complete displacement of the medial orbital wall and orbital floor. Out of a total of 20 patients with orbital fractures, five underwent a surgical intervention of repositioning the medial aspect of the orbital floor and especially the transition area between the orbital floor and medial orbital wall, using navigation-aided procedures. Using the mirroring tool of the Stryker-Leibinger STN-system, post-operative CTs indicated an average difference of the globe position of -4.9% between the operated side and the unaffected side, depending on the position of the medial aspect of the orbital floor. Navigation-aided procedures proved to be an essential precondition for achieving precise and predictable results in orbital reconstruction. In such cases, unlike those with an intact medial orbital wall remnant as a surgical target, bone grafts for reconstruction of the orbital floor cannot be implanted as onlay grafts.

Adult↗