Edela Puricelli

Histological evaluation of the influence of magnetic field application in autogenous bone grafts in rats

BackgroundBone grafts are widely used in oral and maxillofacial reconstruction. The influence of electromagnetic fields and magnets on the endogenous stimulation of target tissues has been investigated. This work aimed to assess the quality of bone healing in surgical cavities filled with autogenous bone grafts, under the influence of a permanent magnetic field produced by in vivo buried devices.MethodsMetal devices consisting of commercially pure martensitic stainless steel washers and titanium screws were employed. Thirty male Wistar rats were divided into 3 experimental and 3 control groups. A surgical bone cavity was produced on the right femur, and a bone graft was collected and placed in each hole. Two metallic washers, magnetized in the experimental group but not in the control group, were attached on the borders of the cavity.ResultsThe animals were sacrificed on postoperative days 15, 45 and 60. The histological analysis of control and experimental samples showed adequate integration of the bone grafts, with intense bone neoformation. On days 45 and 60, a continued influence of the magnetic field on the surgical cavity and on the bone graft was observed in samples from the experimental group.ConclusionThe results showed intense bone neoformation in the experimental group as compared to control animals. The intense extra-cortical bone neoformation observed suggests that the osteoconductor condition of the graft may be more susceptible to stimulation, when submitted to a magnetic field.

Histological analysis of the effects of a static magnetic field on bone healing process in rat femurs

BackgroundThe aim of this study was to investigate, in vivo, the quality of bone healing under the effect of a static magnetic field, arranged inside the body.MethodsA metallic device was developed, consisting of two stainless steel washers attached to the bone structure with titanium screws. Twenty-one Wistar rats (Rattus novergicus albinus) were used in this randomized experimental study. Each experimental group had five rats, and two animals were included as control for each of the groups. A pair of metal device was attached to the left femur of each animal, lightly touching a surgically created bone cavity. In the experimental groups, washers were placed in that way that they allowed mutual attraction forces. In the control group, surgery was performed but washers, screws or instruments were not magnetized. The animals were sacrificed 15, 45 and 60 days later, and the samples were submitted to histological analysis.ResultsOn days 15 and 45 after the surgical procedure, bone healing was more effective in the experimental group as compared to control animals. Sixty days after the surgical procedure, marked bone neoformation was observed in the test group, suggesting the existence of continued magnetic stimulation during the experiment.ConclusionThe magnetic stainless steel device, buried in the bone, in vivo, resulted in increased efficiency of the experimental bone healing process.

Bone Healing After Bur and Er:YAG Laser Ostectomies

PURPOSE Ostectomies, performed by different methods, are often necessary in oral and maxillofacial surgery. Rotatory and reciprocating devices are most frequently used but have disadvantages, such as noise, vibration, and the potential for inducing thermal damage. Laser systems are interesting alternatives to these procedures. We analyzed bone healing in a rat model after mandibular ostectomy with a surgical bur or noncontact erbium:yttrium-aluminum-garnet laser using different energy levels. MATERIALS AND METHODS Four groups of 5 rats each underwent ostectomy of the bone cortical of the mandibular body, with irrigation, using a surgical bur or erbium:yttrium-aluminum-garnet laser with different energy parameters. A metal plate was used for morphologic standardization of the cavities. The samples collected after 7, 14, 45, 60, and 90 days were analyzed by optical microscopy. RESULTS The ostectomies performed with surgical burs resulted in bone healing from the cortical endosteum and remaining trabecular bone. The cortical endosteum was repaired after 45 days, followed by bone remodeling. After laser irradiation, healing involved bone neoformation from the external cortical surface and endosteum. Surface regions with thermal damage were observed after laser treatment in the 3 conditions used up to day 60, followed by bone remodeling. CONCLUSIONS Laser ostectomies resulted in a thin layer of thermal damage. Bone healing was faster when surgical burs were used, with similar results reached after 90 days.

A new technique for mandibular osteotomy

Sagittal split osteotomy (SSO) is a surgical technique largely employed for mandibular mobilizations in orthognatic procedures. However, the traditional design of buccal osteotomy, located at the junction of mandibular ramus and body, may prevent more extensive sliding between the bone segments, particularly on the advance, laterality and verticality of the mandibular body. The author proposes a new technical and conceptual solution, in which osteotomy is performed in a more distal region, next to the mental formamen. Technically, the area of contact between medullary-cancellous bone surfaces is increased, resulting in larger sliding rates among bone segments; it also facilitates the use of rigid fixation systems, with miniplates and monocortical screws. Conceptually, it interferes with the resistance arm of the mandible, seen as an interpotent lever of the third gender.

Characterization of bone repair in rat femur after treatment with calcium phosphate cement and autogenous bone graft

BackgroundIn this study, the biocompatibility, stability and osteotransductivity of a new cement based on alpha-tricalcium phosphate (alpha-TCP) were investigated in a bone repair model using a rat model.MethodsThe potential of alpha-TCP on bone repair was compared to autogenous bone grafting, and unfilled cavities were used as negative control. Surgical cavities were prepared and designated as test (T), implanted with alpha-TCP blocks; negative control (C - ), unfilled; and positive control (C + ), implanted with autogenous bone graft. Results were analyzed on postoperative days three, seven, 14, 21 and 60.ResultsThe histological analyses showed the following results. Postoperative day three: presence of inflammatory infiltrate, erythrocytes and proliferating fibroblasts in T, C - and C + samples. Day seven: extensive bone neoformation in groups T and C + , and beginning of alpha-TCP resorption by phagocytic cells. Days 14 and 21: osteoblastic activity in the three types of cavities. Day 60: In all samples, neoformed bone similar to surrounding bone. Moderate interruption on the ostectomized cortical bone.ConclusionsBone neoformation is seen seven days after implantation of alpha-TCP and autogenous bone. Comparison of C - with T and C + samples showed that repair is faster in implanted cavities; on day 60, control groups presented almost complete bone repair. Alpha-TCP cement presents biocompatibility and osteotransductivity, besides stability, but 60 days after surgery the cavities were not closed.

Panorametry: suggestion of a method for mandibular measurements on panoramic radiographs

BackgroundOrthopantomography (panoramic radiography) has been used for the study of measurements involving particularly the prediction of the eruption of impacted lower third molars and analyses of measurements of the ramus and head of mandible. The discrepancies involved with the projection of this radiographic image has stimulated the search for further ways to use it, particularly in orthodontic treatments and oral and maxillofacial surgeries. The author proposes a graphimetric method for the mandible, based on panoramic radiography. The results are expressed in linear and angular measurements, aiming at bilateral comparisons as well as the determination of the proportion of skeletal and dental structures, individually and among themselves as a whole. The method has been named Panorametry, and allows measurement of the mandible (Mandibular Panorametry) or the posterior mandibular teeth (Dental Panorametry). When combining mandible and maxilla, it should be referred to as Total Panorametry. It may also be used, in the future, with Cone Beam computed tomography (CT) images, and in this case it may be mentioned as CT Panorametry.

Apicotomy: a root apical fracture for surgical treatment of impacted upper canines

Impacted canines, due to systemic or local factors, represent a frequent problem in most populations. Surgical intervention usually involves exposure for spontaneous eruption, exposure for orthodontic traction or extraction. The author presents the apicotomy technique, which has been successfully used during the past twenty years for conservative intervention in cases of impacted upper canines with dilaceration or apical root-ankylosis. This original method involves surgical fracture of the root apex, followed by orthodontic traction of the corono-radicular region.

Pseudoankylosis of the temporomandibular joint caused by zygomatic malformation

Temporomandibular joint (TMJ) pseudoankylosis is characterized by limited mouth opening and mandibular movements, resulting from factors outside the joint. The authors present a case of TMJ pseudoankylosis caused by congenital zygomatic malformation and hyperplasia of the coronoid process. Treatment with coronoidectomy and postoperative physiotherapy achieved favorable results.

Clinical management of angioneurotic oedema patient post-orthognathic surgery

Angioneurotic oedema is an acute swelling involving the submucosal or subcutaneous tissues; it is most often located in the oral and maxillofacial region, which can result in upper airway obstruction. Its aetiology is frequently associated with immunoglobulin-mediated hypersensitivity reactions that elicit a heightened inflammatory response. The objective of this study was to report the case of a patient who developed an episode of angioneurotic oedema following combined orthognathic surgery. Pharmacological and nonpharmacological interventions used in the treatment of this important clinical condition are described and discussed.

Nitrogen-containing bisphosphonate therapy: assessment of the alveolar bone structure in rats – a blind randomized controlled trial

This study aimed to assess the effect of zoledronic acid exposure on structures of the alveolar bone of rats. The sample was composed of 42 male Wistar rats. Animals in the T1 and T2 groups received weekly doses of 0.2 mg/kg intraperitoneal zoledronic acid for 3 weeks, while animals in the T3 group received the same treatment for 8 weeks. The control groups C1, C2 and C3 received equivalent doses of saline. The first upper molars of Wistar rats in the C2, T2, C3 and T3 groups were extracted. Cone‐beam computerized tomography scans were performed, and the image density was analysed by grey levels. The presence and type of inflammatory infiltrate, vascularization and bone necrosis were assigned by histological qualitative scores. Histomorphometric analysis of bone density was performed in the groups without extraction. No significant differences were found in the bone grey density estimated by grey‐level value and histomorphometric analysis between the C1 and T1 groups (P > 0.05). The grey levels in the T3 group were lower (P < 0.05) than in the C3 group, corresponding to the bone defect. Histological assessments showed the presence of bone necrosis in the T3 group and lower levels of bone remodelling in the test groups (T2 and T3) compared to the control groups (C2 and C3). The results of qualitative analyses did not differ significantly between the groups (P > 0.05). Zoledronic acid‐exposed animals showed maxillary changes including reduced grey levels, the presence of bone necrosis and a higher prevalence of inflammatory signs.