Use of fresh frozen bone graft in rehabilitation of maxillar atrophy.

AIM: Fresh frozen bone (FFB) is homologous bone obtained from human donors, provided by Tissue Banks. It is a graft material in reconstructive surgery; it is currently and widely used in orthopedic surgery and lately it has been introduced in oral and maxillofacial surgery. The purpose of this work was to show the use of fresh frozen homologous bone for bony augmentation of the maxilla and mandible in preparation for dental reconstruction with endosseous implants, as an effective alternative to harvesting and grafting autogenous bone from intra- or extra-oral donor sites. METHODS: The case presented clinically demonstrates the use of FFB grafts in the vertical augmentation of a severe maxillary atrophy in general anesthesia, and the outpatient treatment with implants insertion and prosthetic restoration. Histologic evaluation of graft biopsy six months after surgery is added to clinical assessments. RESULTS: Clinical outcome is shown with good volumetric and morphological reconstruction of the alveolar ridge without the need of a donor site. Excellent graft integration and bleeding newly formed bone was seen at the second surgical step (six months after FFB grafting), when fixation screws were removed and implant placement procedure was performed. CONCLUSION: The use of FFB in major preprosthetic surgery may be an acceptable therapeutic alternative to the autogenous block graft (harvested from iliac crest or calvarium) for its success rate as graft material. Benefits include: surgical procedure with reduced discomfort and infection risk as a second operation field to harvest the graft is avoided; FFB is safe, cheap and available in programmed amounts, its use can significantly reduce operating time.

Displacement of a dental implant into the maxillary sinus: case series.

Dental implants placed in the maxilla risk failure because of the low density of the maxillary bone and the shortness of the maxillary ridge. Moreover, inadequate implant preparation, drilling or installation can easily lead to complications related to the maxillary sinuses. Displacement of dental implants into the maxillary sinus can cause serious complications, but there are few reports of such cases. The aim of this paper is to present three cases of a migrated dental implants into the maxillary sinus: in the first two cases the dental implant was found close to the medial wall of the maxillary sinus and was removed through a surgical approach, whereas in the third case the dental implant was spontaneously expelled from the nasal cavities through the mucociliary clearance. The most frequent adverse effect is the local infection of tissue around the implant. For this reason, implants placed close to the maxillary sinus offer a route for infection from the oral cavity to the sinus. While in some cases implant migration causes sinusitis in other, the patients remain asymptomatic; anyway, the treatment depends on the symptoms of maxillary sinusitis. In the third case the dental implant was spontaneously expelled from the nasal graves. Our report illustrates that a powerful mechanism of mucociliary action can cause relatively heavy objects within the maxillary sinus to migrate naturally to the sinus ostia against gravitational force and then to be expelled from the nasal cavities.

Intraosseous anastomosis in the maxillary sinus.

AIM: During sinus-lift surgery, certain intra-osseous vessels may be accidentally cut and this cause bleeding complications in approximately 20% of osteotomies. Therefore, understanding vascular details of the maxilla is very important for the surgeon. Here, we have given an anatomical overview of maxillary sinus vascularization through anatomical dissection. We have analyzed the distribution, localization and distance from the alveolar ridge of intraosseous branches of the maxillary artery found during sinus lift surgery. METHODS: Fifty-six maxillary bone doors were made bilaterally in twenty-eight unfixed cadavers; the doors were made between the first molar and the second molar (24 doors) or between the first and the second premolar (32 doors). RESULTS: Intraosseous arteries were found in 37 maxillary bones (66%). The average height of the artery from the alveolar crest was 13+/-3.2 mm in the distal doors and 18 +/- 6.1 mm in the mesial doors. Generally, the intraosseous maxillary branches ran caudo-rostrally; but in five maxillae, we found two parallel arteries, while in three cases the maxillary artery ran vertically. No differences were found between the left and right side. CONCLUSION: The risk of vascular damage in sinus floor elevation surgery is a real problem for the oral surgeon. Detailed anatomical knowledge about sinus vascularization is very important to reduce the risk of vascular damage and bleeding. In addition the visualization of sinus anastomosis by radiology and less invasive surgery, such as piezo-surgery, could be helpful.

What is the best test to predict outcome after prolonged cardiac arrest?

Multimodality evoked potentials (EPs), linear electroencephalograms and Glasgow Coma Scale (GCS) scores were recorded within 24 h of cardiac arrest in 62 patients who were comatose following cardiopulmonary resuscitation. The cardiac arrest had a cardiac cause in 35 patients and a non-cardiac cause in 27 patients. The Glasgow Outcome Scale (GOS) scores were established 6 months after resuscitation. The prognostic value of all the recorded variables was calculated in terms of sensitivity, specificity and accuracy. Spearman's rank test was also used for the determination of the correlation coefficients with GOS. EP recordings furnished no falsely pessimistic predictions, with a specificity of 100%. In other words, when EPs were altered, the prognosis was always poor. However, while all patients who regained consciousness had normal EPs, not all patients in whom EPs were recordable survived. The GCS score showed a higher sensitivity and correlation with GOS score than EPs, but it was associated with a high percentage of false positive results, and its specificity was only 67%. The combination of the GCS score with EPs may be a promising strategy to counterbalance the respective limits of these methods and to reduce the loss of information due to sedation and myorelaxation, which impede clinical examination but not EP results.

TGF-beta1 and VEGF after fresh frozen bone allograft insertion in oral-maxillo-facial surgery.

Bone regeneration technique using allografts is widely used in oral surgery to repair alveolar defects and to increase alveolar volume for endosseous implant insertions. Bone allografts promote the reabsorption and neo-synthesis of bone tissue, which are regulated by numerous cytokines, proteins and growth factors. In this study, six patients with insufficient alveolar volume for endosseous implant insertions, were treated with bone regeneration technique using Fresh Frozen Bone (FFB) allografts collected from the femoral head or the hip. Samples of bone graft collected during graft insertion surgery and biopsies collected six months later during implantology were fixed, decalcified and analyzed histomorphologically and morphometrically by haematoxylin-eosin staining. In addition, TGF-beta1 and VEGF were analyzed by immunohistochemistry. The histological analysis of FFBs showed wide areas of calcified bone organized in osteons intermingled with areas of non-calcified matrix containing osteoblasts. However, the regenerated alveolar bone, collected six months after the graft insertion surgery, showed wide areas of non-calcified matrix. TGF-beta1 and VEGF were less expressed in FFB than in regenerated alveolar bone.