1/16. Scanning electron microscopic observations of 'fractured' biodegradable plates and screws.BACKGROUND: We encountered two out of 100 cases in which implanted biodegradable plates and screws had fractured within 1 month postoperatively. MATERIAL: Failure of the material was confirmed through clinical symptoms, radiographs or CT findings. In addition, four specimens obtained from these two cases were examined with regard to their ultrastructure using scanning electron microscopy. RESULTS: Several principal patterns of the fractured surface were found: (1) gradual cracking, i.e. 'circular stair' and, (2) tortuous threads, i.e. a wavy line. It is conceivable that the material may not have been hit by major sudden forces but a disproportion between the thread configuration and the drilled hole may have led to screw loosening and torsion. Subsequently, the threads were deformed in a 'wavy' manner, finally leading to cracking and fracture of plates and screws. Fractures of plates and screws due to these instabilities are thought to be distinguishable from material resorption. CONCLUSION: In the application of biodegradable materials, more than two screws per single bone segment should be used as a principle of plate-fixation technique in order to avoid a stability-compromising situation, particularly in the stress-bearing areas of the maxillofacial region. Moreover, three-dimensional fixation using more than two plates is recommended in the facial skeleton e.g. zygomatic tripod. Intermaxillary fixation should also be considered to reinforce initial stability in stress-bearing areas.- - - - - - - - - - ranking = 1keywords = resorption (Clic here for more details about this article) |
2/16. Chronic osteomyelitis: 20 years after mandible fracture.Chronic osteomyelitis is a persistent abscess of the bone that is characterized by the usual complex of inflammatory processes, including necrosis of mineralized and marrow tissues, suppuration, resorption, sclerosis, and hyperplasia. The purpose of this paper is to report a case of chronic osteomyelitis seen 20 years after mandible fracture.- - - - - - - - - - ranking = 1keywords = resorption (Clic here for more details about this article) |
3/16. Spontaneous fracture of hypertrophied genial tubercles.A case of spontaneous fracture of hypertrophied genial tubercles is reported. This is an uncommon event with only six previously reported cases. This entity is usually associated with severe edentulous bone resorption, a condition related to the pathogenesis of this fracture. Clinical complaints include painful swelling of the floor of the mouth and impaired tongue function. If left untreated, mucosal inflammatory changes may appear and a biopsy should be performed. Total recovery is obtained after removal of the fractured fragments.- - - - - - - - - - ranking = 1keywords = resorption (Clic here for more details about this article) |
4/16. Postoperative fractures of the lingual plate after bilateral sagittal split osteotomies.We encountered the unusual complication of postoperative fracture of the lingual plate in four patients after bilateral sagittal split osteotomy. We then did a retrospective review to identify possible risk factors. Over a 1-year period we did 52 bilateral split osteotomies. The patients' casenotes were examined and a number of variables were recorded, including surgical technique, and the patient's sex, age, presence or absence of third molars, and the height of the mandible in the region of the osteotomy. Significant risk factors were a vertical mandibular height of 2 cm or less distal to the last molar tooth (p=0.02), and a depth of 0.6 cm or less from the apex of last molar root or impacted third molar to the lower border (p=0.005).- - - - - - - - - - ranking = 0.0070693923894793keywords = root (Clic here for more details about this article) |
5/16. Mandibular fracture 2 weeks after third molar extraction.This case report describes mandibular fracture after the surgical extraction of fully erupted lower third molar of a 53-year-old healthy male patient. The fracture occurred 15 days after the extraction while chewing. The fracture line extended from the apex of the mesiobuccal root socket to the inferior border of the mandible. Follow-up of the patient was agreed as the patient was not willing to carry on further treatment. Bony union was observed radiologically 3 months later.- - - - - - - - - - ranking = 0.0070693923894793keywords = root (Clic here for more details about this article) |
6/16. Management of mandibular fractures in patients with endosseous implants.Seven patients who had previously received mandibular endosseous implants sustained mandibular fractures and were treated. Three patients had advanced bone resorption and developed stress fractures through previous endosseous implant sites. Two patients sustained fractures through implant sites via trauma. Two patients sustained fractures anatomically separated from the implants, which caused an alteration in the dental occlusion. This report describes the treatment approach for these seven patients and reviews the treatment philosophy and procedures involved. A conservative treatment approach is advised when the fracture transverses through a stable or a recently failed implant site.- - - - - - - - - - ranking = 1keywords = resorption (Clic here for more details about this article) |
7/16. Management of malunited mandibular condylar fractures.The non-surgical treatment of mandibular condylar fractures, may occasionally result in articular imbalance and temporomandibular joint dysfunction. This may be attributed to condylar head displacement and resorption, resulting in a shortened vertical ramus and lost posterior vertical facial height. Restoring the vertical ramus height is essential in the treatment of such dysfunction, and may be accomplished by unilateral, or bilateral ramus osteotomies. Four examples of patients treated with mandibular ramus osteotomies to restore vertical ramus height, with subsequent improvement in occlusal balance and function are presented. The use of the sagittal split mandibular osteotomy and the external vertical ramus osteotomy, stabilized with small osseous plates, and monocortical screws, is discussed.- - - - - - - - - - ranking = 1keywords = resorption (Clic here for more details about this article) |
8/16. A histologic evaluation of a mandibular cross section one year after augmentation with hydroxyapatite particles.A pathologic mandibular fracture in a 35-year-old woman 1 year after the attempted filling of a bone defect with particulate, dense hydroxyapatite resulted in a partial mandibular resection, allowing observation of cross sections of the mandible and associated soft tissue. Thin tissue sections were examined without decalcification. This permitted excellent observation of the hydroxyapatite particles, the bone, and the soft tissue. osseointegration had occurred only in the areas closely associated with the bone. The immobility of the particles was a prerequisite for involvement with new bone formation. Hydroxyapatite particles in areas that allowed any mobility were surrounded by connective tissue with no bone formation evident. Heterogeneous particles were observed, indicating the possibility of a lack of purity in the hydroxyapatite ceramic, which may have contributed to the resorption of the particles. These findings, as well as other clinical and experimental findings, lead us to question the concept of hydroxyapatite as a bioactive ceramic that induces osteogenesis or osteoconductivity.- - - - - - - - - - ranking = 1keywords = resorption (Clic here for more details about this article) |
9/16. The use of freeze-dried rib and hydroxylapatite in the treatment of a fracture occurring in a patient with familial facial osteodystrophy.The treatment of repeated pathologic fractures of the mandible has long taxed the ingenuity of surgeons. The complexity of the problem increases with the recognition of a metabolic defect that renders the facial bones hypoplastic. In the case presented, a tentative diagnosis of familial facial osteodystrophy was made at the National Institutes of health. Since that time, the patient has undergone autogenous onlay grafting, which has completely resorbed. Because of continuous resorption, a number of pathologic fractures have occurred. The most recent fracture was treated by means of a freeze-dried rib, which acted as a floor and as a splint to the fracture site. Hydroxylapatite and a marrow mixture were placed on the floor to gain height, strength, and durability. Subsequently, hydroxylapatite augmentation was performed to gain a more anatomic alveolar ridge. The patient's 12-month follow-up has shown the mandible to be intact with no noticeable change in either vertical or horizontal dimensions.- - - - - - - - - - ranking = 1keywords = resorption (Clic here for more details about this article) |
10/16. Cranial bone grafts for post-traumatic facial defects.Recent interest in onlay cranial bone grafts has shown it to be a preferred technique in the reconstruction of facial defects. This paper reports seven patients in whom outer table cranial bone grafts were used to reconstruct post-traumatic facial deformities. These included orbital and zygomatic deformities (2 patients), maxillary defects (2 patients), mandibular defects (2 patients), and nasal deformity (1 patient). A brief review of the development of membranous bone grafting for maxillofacial reconstruction is given. Good cosmetic results were obtained in six of seven patients with no evidence of graft resorption. One patient required removal of the graft because of inadequate soft tissue coverage. No patient suffered any significant donor site morbidity. In summary, this technique is extremely useful in treating post-traumatic bony deformities of the facial skeleton. The excellent graft survival and ease in harvesting the graft make this technique preferable to traditional endochondral grafts taken from the iliac crest and rib.- - - - - - - - - - ranking = 1keywords = resorption (Clic here for more details about this article) |
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