Paulo Esteves Pinto Faria

Immunohistochemical, tomographic and histological study on onlay bone graft remodeling. Part II: Calvarial bone

OBJECTIVES Little information is available on the molecular events that occur during graft incorporation over time. The calvarial bone (Cb) grafts have been reported to produce greater responses compared with other donor regions in maxillofacial reconstructions, but the scientific evidences for this are still lacking. The objectives of this study are (1) to study the morphological pattern of Cb onlay bone grafts and compare them with the biological events through immunohistochemical responses and (2) to establish the effects of perforations in maintaining the volume and bone density of the receptor bed. MATERIAL AND METHODS Sixty New Zealand White rabbits were submitted to Cb onlay bone grafts on the mandible. In 30 rabbits, the receptor bed was perforated (perforated group), while for the remaining animals the bed was kept intact (non-perforated group). Six animals from each group were sacrificed at 5, 7, 10, 20 and 60 days after surgery. Histological sections from the grafted area were prepared for immunohistochemical and histological analyses. Immuno-labeling was found for proteins Osteoprotegerin (OPG), receptor activator of nuclear factor-kappabeta ligand (RANKL), alkaline phosphatase (ALP), osteopontin (OPN), vascular endothelial growth factor (VEGF), tartrate-resistant acid phosphatase (TRAP), Type I collagen (COL I) and osteocalcin (OC). The tomography examination [computerized tomography (CT) scan] was conducted just after surgery and at the sacrifice. RESULTS The histological findings revealed that the perforations contributed to higher bone deposition during the initial stages at the graft-receptor bed interface, accelerating the graft incorporation process. The results of the CT scan showed lower resorption for the perforated group (P<or=0.05), and both groups showed high bone density rates at 60 days. This set of evidences is corroborated by the immunohistochemical outcomes indicating that proteins associated with revascularization and osteogenesis (VEGF, OPN, TRAP and ALP) were found in higher levels in the perforated group. CONCLUSIONS These findings indicate that the bone volume of calvarial grafts is better maintained when the receptor bed is perforated, probably resulting from more effective graft revascularization and greater bone deposition. The process of bone resorption peaked between 20 and 60 days post-operatively in both groups although significantly less in the perforated group.

Immunohistochemical, tomographic and histological study on onlay iliac grafts remodeling

The information concerning the molecular events taking place in onlay bone grafts are still incipient. The objective of the present study is to correlate the effects of perforation of resident bone bed on (1) the timing of onlay autogenous graft revascularization; (2) the maintenance of volume/density of the graft (assessed through tomography); and (3) the occurrence of bone remodeling proteins (using immunohistochemistry technique) delivered in the graft. Thirty-six New Zealand White rabbits were subjected to iliac crest onlay bone grafting on both sides of the mandible. The bone bed was drill-perforated on one side aiming at accelerating revascularization, whereas on the other side it was kept intact. After grafts fixation and flaps suture all animals were submitted to tomography on both mandible sites. Six animals were sacrificed, respectively, at 3, 5, 7, 10, 20 and 60 days after surgery. A second tomography was taken just before sacrifice. Histological slides were prepared from each grafted site for both immunohistochemistry analysis [osteopontin, osteocalcin, type I collagen and vascular endothelial growth factor (VEGF) anti-bodies] and histometric analysis. The values on bone volume measured on tomography showed no statistic significance (P>or=0.05) between perforated and intact sites. Grafts placed on perforated beds showed higher bone density values compared with non-perforated ones at 3 days (P<or=0.05). This correlation was inverted at 60 days postoperatively. The findings from VEGF labeling revealed a tendency for earlier revascularization in the perforated group. The early revascularization of bone grafts accelerated the bone remodeling process (osteocalcin, type I collagen and osteopontin) that led to an increased bone deposition at 10 days. The extended osteoblast differentiation process at intermediate stages in the perforated group cooperated for a denser bone at 60 days.

Histological Findings Following the Use of a Space-Making Device for Bone Reformation and Implant Integration in the Maxillary Sinus of Primates

BACKGROUND Previous studies have shown that membrane elevation results in predictable bone formation in the maxillary sinus provided that implants can be placed as tent poles. In situations with an extremely thin residual crest which impairs implant placement, it is possible that a space-making device can be used under the sinus membrane to promote bone formation prior to placement of implants. PURPOSE The present study was conducted to test the hypothesis that the use of a space-making device for elevation of the sinus membrane will result in predictable bone formation at the maxillary sinus floor to allow placement of dental implants. MATERIALS AND METHODS Eight tufted capuchin primates underwent bilateral sinus membrane elevation surgery, and a bioresorbable space-making device, about 6 mm wide and 6 mm in height, was placed below the elevated membrane on the sinus floor. An oxidized implant (Nobel Biocare AB, Gothenburg, Sweden) was installed in the residual bone protruding into the created space at one side while the other side was left without an implant. Four animals were sacrificed after 6 months of healing. The remaining four animals received a second implant in the side with a space-making device only and followed for another 3 months before sacrifice. Implant stability was assessed through resonance frequency analysis (RFA) using the Osstell (Osstell AB, Gothenburg, Sweden) at installation, 6 months and 9 months after the first surgery. The bone-implant contact (BIC) and bone area inside the threads (BA) were histometrically evaluated in ground sections. RESULTS Histologically there were only minor or no signs of bone formation in the sites with a space-making device only. Sites with simultaneous implant placement showed bone formation along the implant surface. Sites with delayed implant placement showed minor or no bone formation and/or formation of a dense fibrous tissue along the apical part of the implant surface. In the latter group the apical part of the implant was not covered with the membrane but protruded into the sinus cavity. CONCLUSIONS The use of a space-making device, with the design used in the present study, does not result in bone formation at the sinus floor. However, membrane elevation and simultaneous placement of the device and an implant does result in bone formation at the implant surface while sites with implants placed 6 months after membrane elevation show only small amounts of bone formation. It is suggested that lack of stabilization of the device and/or a too extensive elevation of the membrane may explain the results.

Bone formation following implantation of titanium sponge rods into humeral osteotomies in dogs: a histological and histometrical study.

BACKGROUND Titanium (Ti) is widely proven to enhance bone contact and growth on its surface. It is expected that bone defects could benefit from Ti to promote healing and to increase strength of the implanted area. PURPOSE The present study aimed at comparing the potential of porous Ti sponge rods with synthetic hydroxyapatite (HA) for the healing of bone defects in a canine model. MATERIAL AND METHODS Six mongrel dogs were submitted to three trephined osteotomies of 6.0 x 4.0 mm in one humerus and after 2 months another three osteotomies were performed in the contralateral humerus. A total of 36 defects were randomly filled either with Ti foam, particulate HA, or coagulum (control). The six animals were killed 4 months after the first surgery for histological and histometrical analysis. RESULTS The Ti-foam surface was frequently found in intimate contact with new bone especially at the defect walls. Control sites showed higher amounts of newly formed bone at 2 months - Ti (p = 0.000) and HA (p = 0.009) - and 4 months when compared with Ti (p = 0.001). Differently from HA, the Ti foam was densely distributed across the defect area which rendered less space for bone growth in the latters sites. The use of Ti foams or HA resulted in similar amounts of bone formation in both time intervals. Nevertheless, the presence of a Ti-foam rod preserved defects marginal bone height as compared with control groups. Also, the Ti-foam group showed a more mature bone pattern at 4 months than HA sites. CONCLUSION The Ti foam exhibited good biocompatibility, and its application resulted in improved maintenance of bone height compared with control sites. The Ti foam in a rod design exhibited bone ingrowth properties suitable for further exploration in other experimental situations.

Reconstruction of Mandibular Segmental Defects Using the Guided-Bone Regeneration Technique With Polylactide Membranes and/or Autogenous Bone Graft: A Preliminary Study on the Influence of Membrane Permeability

PURPOSE Bone maintenance after mandibular reconstruction with autogenous iliac crest may be disappointing due to extensive resorption in the long term. The potential of the guided-bone regeneration (GBR) technique to enhance the healing process in segmental defects lacks comprehensive scientific documentation. This study aimed to investigate the influence of polylactide membrane permeability on the fate of iliac bone graft (BG) used to treat mandibular segmental defects. MATERIALS AND METHODS Unilateral 10-mm-wide segmental defects were created through the mandibles of 34 mongrel dogs. All defects were mechanically stabilized, and the animals were divided into 6 treatment groups: control, BG alone, microporous membrane (poly L/DL-lactide 80/20%) (Mi); Mi plus BG; microporous laser-perforated (15 cm(2) ratio) membrane (Mip), and Mip plus BG. Calcein fluorochrome was injected intravenously at 3 months, and animal euthanasia was carried out at 6 months postoperatively. RESULTS Histomorphometry showed that BG protected by Mip was consistently related to larger amounts of bone compared with other groups (P <or= .0001). No difference was found between defects treated with Mip alone and BG alone. Mi alone rendered the least bone area and reduced the amount of grafted bone to control levels. Data from bone labeling indicated that the bone formation process was incipient in the BG group at 3 months postoperatively regardless of whether or not it was covered by membrane. In contrast, GBR with Mip tended to enhance bone formation activity at 3 months. CONCLUSIONS The use of Mip alone could be a useful alternative to BG. The combination of Mip membrane and BG efficiently delivered increased bone amounts in segmental defects compared with other treatment modalities.

Effects of early functional loading on maintenance of free autogenous bone graft and implant osseointegration: an experimental study in dogs.

PURPOSE The aim of the present study was to investigate the healing, integration, and maintenance of autogenous onlay bone grafts and implant osseointegration either loaded in the early or the delayed stages. MATERIALS AND METHODS A total of 5 male dogs received bilateral blocks of onlay bone grafts harvested from the contralateral alveolar ridge of the mandible. On one side, the bone block was secured by 3 dental implants (3.5 mm x 13.0 mm, Osseospeed; AstraTech AB, Mölndal, Sweden). Two implants at the extremities of the graft were loaded 2 days after installation by abutment connection and prosthesis (simultaneous implant placement group); the implant in the middle remained unloaded and served as the control. On the other side, the block was fixed with 2 fixation screws inserted in the extremities of the graft. Four weeks later, the fixation screws were replaced with 3 dental implants. The loading procedure (delayed implant placement group) was performed 2 days later, as described for the simultaneous implant placement sites. The animals were sacrificed 12 weeks after the grafting procedure. Implant stability was measured through resonance frequency analysis. The bone volume and density were assessed on computed tomography. The bone to implant contact and bone area in a region of interest were evaluated on histologic slides. RESULTS The implant stability quotient showed statistical significance in favor of the delayed loaded grafts (P = .001). The bone-to-implant contact (P = .008) and bone area in a region of interest (P = 0.005) were significantly greater in the delayed group. Nevertheless, no difference was found in terms of graft volume and density between the early loaded and delayed-loaded approaches. CONCLUSIONS The protocol in which the implant and bone graft were given delayed loading allows for effective quality of implant osseointegration and stabilization, with healing and remodeling occurring in areas near the implant resulting in denser bone architecture.

Effects of Photodynamic Process (PDP) in Implant Osseointegration: A Histologic and Histometric Study in Dogs

BACKGROUND The combination between photosensitivity substances with laser or light-emitting diode (LED) form the photodynamic therapy basis that consists of photosensitivity drug activated by low-frequency light. This mechanism is used in soft tissue healing process to improve the oxygen tension leading to a fast revascularization. PURPOSE The objective of this study was to evaluate the effects of photosensitivity drugs activated through LED on osseointegration process. MATERIALS AND METHODS Eight mongrel dogs underwent implant therapy in four mandibular bone defects using 5.0 mm trephine drill on each side of the mandible. The defects were randomly filled up with (1) Nano emulsion, (2) liposome, (3) blood clot, and (4) autogenous bone. LED with visible and infrared light were applied after 48/72 postoperative hours on four dogs and after 96/120 postoperative hours in the other four dogs. All the animals were euthanized at 15 days after surgery. Ground sections slides were prepared from the experimental site for histomorphometry and histological analysis. RESULTS No difference was detected in the following parameters: bone-implant contact, bone inside the defect and crest level on LED 48/72. Significant difference was detected inside the defect when filled with autogenous bone (p = .0238) on LED 96/120. When LED 48/72 and LED 96/120 were compared, significant higher bone formation was detected when autogenous bone on bone-implant contact (p = .0043) and bone inside the defect (p = .0008) was used. CONCLUSION The use of photosensitivity drugs activated by LED demonstrated a tendency to stimulate bone formation, similar to autogenous bone graft on later time point.

Lingual Short Split: A Bilateral Sagittal Split Osteotomy Technique Modification

The technique of sagittal split osteotomy of the mandibular ramus is an established technique that has been evolving over the years, with significant improvements regarding stability, better bone contact between the segments, and possibilities of osteosynthesis. However, paresthesia is common in the postoperatory, sometimes permanent, and undesirable fractures in the subcondylar region can occur leading to longer operative time and extraoral scars. The short lingual split technique is an easy technique that simplifies the horizontal osteotomy of the ramus and decreases the risk of undesirable fractures with a neurosensitive recovery of patients in a much shorter time because of minor trauma and nerve manipulation during the execution.

Outcomes in Surgical Treatment of Mucocele in Frontal Sinus

Abstract The aim of the study was to correlate several studies dating from 1997 to 2015 to identify the most effective treatments for mucocele in the frontal sinus (with/without other paranasal sinuses), considering successful outcomes and recurrence. We aimed to conduct a literature review for articles published between 1997 and 2015. For this, we accessed articles in the SciELO database, as well as LILACS, PubMed, and Google Scholar databases. Were identified 32 work-related injuries in the paranasal sinuses; 2 of these were not related to mucoceles or mucopyocele, 4 had no relation to the frontal sinus, 9 were related to the frontal sinus and other paranasal sinuses, 4 were related to mucocele associated with other sinuses, and 13 involved only the frontal sinus. Endoscopic techniques decrease intra- and postoperative morbidity, reducing the operative time, allow a larger view of the lesion and surrounding anatomical structures, and decrease chances of recurrence. Thus, the successful outcomes have been beneficial to both the surgeon and the patient.

Surgical Reconstruction of Lower Face Degloving

AbstractOne of the most impressive soft tissue injuries is the facial degloving, normally associated with industrial machines and traffic accidents. This injury is characterized by the separation of the skin and cartilage from the bones, compromising the soft tissues correlated in the trauma area, nerves, and blood vessels. A 28-year-old patient, male, was referred to Araçatubas Santa Casa Hospital, after a motorcycle accident, hitting his face on the sidewalk. The patient was conscious, oriented, denying fainting and unconsciousness during the accident, and complaining of pain in the nasal region of the face. The suture of wounds was performed using 5-0 absorbable sutures for muscle planes, and reconstruction of the septum and nasal cartilages. The skin was sutured with interrupted stitches using 6-0 nylon. After reducing the edema, a slight increase in alar base was observed. Subsequently, the alar base cinch suture was performed aiming to bring the alar bases to a measure of 34.0 mm in diameter. As a conclusion, the knowledge of the anatomy of the region involved, the healing of tissues, and suture techniques for the facial region process were critical to the successful treatment. The evaluation of the alar base in degloving cases can involve aesthetic features.