Bl Sapru

ODONTOAMELOBLASTOMA : A RARE ODONTOGENIC TUMOUR

The odontoameloblastoma is a rare mixed odontogenic tumour originating from proliferating epithelial and mesenchymal components characterized by simultaneous occurrence of ameloblastoma and composite odontoma [1, 2, 3, 4, 5, 6, 7, 8]. So, few cases have been reported in literature till date that any statistical data regarding this disease may not be valid [6]. Approximately 45 cases have been reported in world literature but very few have the histologic and clinical criteria of odontoameloblastoma [1]. This lesion has various synonyms like ameloblastic odontoma, odontoblastoma, adamento-odontoma and calcified mixed odontogenic tumour [6]. It usually occurs between 6 months to 40 years predominantly involving mandible with predilection for molar-premolar region [1, 3]. It is an expansile centrally destructive lesion exhibiting slow growing characteristics like ameloblastoma and if left untreated may cause considerable facial deformity. Symptoms include a slowly progressive swelling of the alveolar plates, dull pain, an altered occlusion, delayed eruption or impacted teeth. Radiologically the tumor presents as a well defined unilocular or multilocular radiolucent cavity containing varying amounts of radio-opaque material, which may or may not bear resemblance to formed, albeit miniature teeth. It may also be in form of small, dense particles or as a large central mass leading to divergence of adjacent tooth roots [1, 6]. Histologically the tumour consists of ameloblasts, enamel matrix, dentin, dental papilla, bone and cementum as well as stromal connective tissue. The classical picture is the presence of sheets of typical ameloblastoma of one or another type of recognized variety. The ameloblast cells may arrange themselves in cord or follicular pattern [6]. As this tumour resembles ameloblastoma in clinical behaviour aggressive treatment modality like en-bloc or segmental resection is advocated [6]. Case Report 36 year old patient was referred to maxillofacial clinic for evaluation and management of slowly growing swelling over right lower jaw since last 6 months. Examination revealed a bony hard, sessile, non-pulsatile, fixed, non-ulcerated, mildly tender diffuse swelling of 4×2 cm size extending from 46-41 region, involving both buccal and lingual cortex with 43 missing and 45 slightly mobile [Fig-1]. Mucosa over the swelling was mobile and normal in colour. Radiograph revealed a multiocular radiolucent lesion extending from 47-42 with multiple radio-opaque masses resembling tooth like structures. The histological examination revealed proliferating odontogenic epithelium in mature connective tissue stroma. The neoplastic odontogenic epithelium forming islands and cords between the dysplastic dentinoid and enamel with reverse nuclear polarization, typical of follicular ameloblastoma was observed (Fig-2). The patient was managed with en-bloc resection of the tumor mass along with 1 cm of healthy margin preserving the continuity of the inferior border of mandible. Comoys solution was applied to resected margin and frozen section was carried out to rule out any left over neoplastic tissue. The resected specimen was further examined to confirm the diagnosis. The primary reconstruction was not carried out as most of the recurrences have been reported to occur within first 3 months of surgical intervention as per available literature. After 3rd post-operative month the Fig. 1 Intra-oral view of the lesion Fig. 2 Histopathological picture of odonto-ameloblastoma patient was taken up successfully for mandibular reconstruction with autogenous cortico-cancellous iliac crest bone graft (Fig-3). The patient was evaluated periodically for any recurrence for one year. ... Discussion Odontoameloblastoma or ameloblastic odontoma has generated much controversy and confusion in literature as evidenced by reporting of ameloblastic fibro-odontomas, developing odontomas and odontoameloblastomas under the terms of ameloblastic odontoma. Choukus and Tots (1964) suggested that the ameloblastoma and odontoma may develop separately and due to invasive growth of the former odontoma becomes surrounded by the more aggressive ameloblastoma thus producing a true collision tumour. To clarify the confusion, WHO subdivided the category into ameloblastic fibro-odontoma and odontoameloblastoma based on their clinical course and histological picture [9]. Ameloblastic fibro-odontoma is a slow growing tumour, which can be treated effectively by enucleation. It does not spread between bony trabeculae and has low recurrence rate. However, odontoameloblastoma is a locally invasive, aggressive odontogenic tumour, which spreads by infiltrating between the bony trabeculae. This characteristic was also observed in our case both clinically and histopathologically. From the histological picture of the lesion it is apparent that the hard tissue formed, are of hamartomatous nature due to presence of enamel, dentin and pulpal tissue. However, ameloblastoma is intermingled with the hard tissue forming a tumorous mass. Fig. 3 Mandibular reconstruction with autogenous iliac crest bone graft The tumour behaves like ameloblastoma and tends to recur particularly when treated conservatively. The effective methods of treatment are en-bloc resection or complete resection of affected part of bone irrespective of size of the lesion. Early and periodic follow-up is also advised to detect any possible relapse.

EFFICACY OF INDIGENOUSLY MANUFACTURED TITANIUM BONE PLATES AND SCREWS IN MAXILLOFACIAL SURGERY

Titanium plates and screws (implants) developed indigenously by DRDO were used to manage 20 patients with maxillofacial fractures. Efficacy of these implants was evaluated clinically and radiographically so that these can be put into use on routine basis. In 18 patients recovery was uneventful. Extended maxillomandibullar fixation was employed for 3 to 7 days only depending on the degree and displacement of fractures and; mobilisation of jaw was allowed fully from 7th post operative day onwards. 2 patients developed discharging sinus at the fractured mandibular angle region which was due to impacted mandibular third molar in the line of fracture. This healed completely after extraction of offending tooth and appropriate medication. There was no occlusal or nerve disturbances, wound dehiscence or rejection of the bone implant. Radiographical evaluation at various intervals showed good alignment, approximation and sound healing of fractured fragments, with complete osteointegration.

EWING'S SARCOMA OF MANDIBLE – A RARE NEOPLASM

Ewings sarcoma is a highly malignant tumour seen in the age group of 5 to 25 years, primarily afflicts long bones of the extremities followed by pelvis, ribs and vertebrae. The involvement of this lesion in the mandible accounts for only 2% of the reported cases. Ewings sarcoma particularly in children, poses difficulty in arriving at a diagnosis and could be established only by histopathological and electron microscopic examination. This is a radiosensitive lesion, however, surgery with chemotherapy is the preferred treatment of choice in mandible. A case of Ewings sarcoma in a 7 year old female patient was managed by chemotherapy and aggressive surgical approach with gratifying results and no recurrence till date.

ORTHODONTICS: CURRENT PRINCIPLES AND TECHNIQUES

The latest edition of this well known textbook in orthodontics has 21 chapters out of which 6 are written by new authors on new subjects. These new chapters are: The temporomandibular disorder patient, Biomaterials in orthodontics, Statistics for the orthodontist, Tip edge appliance, Non extraction treatment and Treatment options for sagittal corrections in non compliant patients. Other chapters have been revised to incorporate advances in techniques and treatment and some completely redone to incorporate ever expanding developments in the field. Interface of orthodontics and periodontics in Chapter 18 and multidisciplinary care in adult orthodontics have been given extra emphasis. Chapter 20 on orthodontic aspects of orthognathic surgery remains a must-read for all interested in the subject. The comprehensiveness of this book makes it a good text and reference book for all students and teachers of orthodontics.

“DISTRACTION OSTEOGENESIS” AN EMERGING CONCEPT IN THE CORRECTION OF CRANIOFACIAL DEFORMITIES

Correction of complex craniofacial deformities in anteroposterior, transverse and vertical planes, is one of the most challenging problems in oral and maxillofacial surgery. Facial development depends upon primary interactions between genetic instructions for morphogenesis and the capacity in the local tissues for the unhindered completion of complex metabolic processes, which are necessary for cell replication, survival and programmed cell death. Morphogenesis and growth may be influenced by factors as diverse as chromosomal anomalies on one hand resulting in congenital deformities such as Craniofacial scoliosis, Goldenhar, Nagers, Pfeiffers and Pierre Robin syndromes, which have got multifocal involvement like mandibular hypoplasia, facial asymmetry with deviation of the chin to the affected side, hypoplasia of the investing soft tissues, associated with microtia; interacting environmental factors on the other hand like mandibular growth deficiencies resulting from condylar fractures and temporomandibular joint ankylosis suffered at an early age, causing considerable aesthetic deformity and functional disability. All these defects require invasive treatment to achieve functional growth as well as quality of the final aesthetics. Skeletal deformities like maxillomandibular hypoplasia, facial asymmetry, congenital micrognathia and other such deformities, have been managed in the past by osteotomies either on the mandible or maxilla or both, followed by acute orthopaedic movements and skeletal fixation, with or without interpositional bone grafts. However, these treatment modalities have several limitations such as impaired vitality of toothbuds, neurological incompetence and inability of the muscles and soft tissues to be acutely stretched without the inherent risk of relapse. Moreover, various types of autogenous bone grafts, harvested from a distant site, allogenic and xeno-grafts and prosthetic implants used to camouflage and correct these defects, are associated with a high rejection and relapse rate, a requirement of blood transfusions, prolonged maxillomandibular fixation and tracheostomies. Surgical interventions to correct these deformities permit only acute changes in the spatial arrangement of bones with limited scope for new bone growth. It does not allow complete bone sculpting, i.e. changing the shape and form of the bones to deal with the three-dimensional structural, functional and aesthetics needs of the patient. An alternative approach of “Distraction osteogenesis” to correct these deformities is a new horizon in the field of craniomaxillofacial reconstructive surgery. This is a versatile technique directed at modulating de novo bone growth and involves stimulation of the genetically in built potency of the local tissue to increase in bulk, rather than transfer of it from another site. The concept of Distraction osteogenesis popularized by Gavriel Ilizarov [1] in correction of deformities of long bones, such as the femur, was first tried by Snyder [2], experimentally in dogs, for mandibular reconstruction. The technique was then successfully applied to the craniofacial region by McCarthy [3] who lengthened the malformed human mandible. Subsequently, other case reports using different types of distractors have been published, with encouraging results. The latter half of the last decade has witnessed a resurgence of this technique which has become increasingly popular and opened new therapeutic perspectives for the treatment of numerous congenital and acquired craniomaxillofacial deformities, the most commonly encountered one being, mandibular hypoplasia with facial asymmetry as a consequence of temporomandibular joint ankylosis resulting from trauma. In Distraction osteogenesis, tissues are subjected to slow and steady physiological traction and become metabolically activated with increased biosynthetic cellular function and proliferation. There is generation of new bone in a gap between two bone segments in response to the application of a graduated tensile stress across the bone gap. A unique feature of the distraction technique is that bone regeneration by distraction osteogenesis is accompanied by simultaneous expansion of the functional soft tissue matrix, including blood vessels, nerves, muscles, skin, mucosa, fascia, ligaments, cartilage and periosteum. These adaptive changes of the surrounding soft tissues through the tension that is generated by the distraction forces applied on the bone, is also termed as “Distraction histogenesis”. With the advent of miniaturized intraoral distractors [4], the technique of distraction osteogenesis has drastically transformed the concept of correction of maxillofacial deformities. They have manifold advantages [5] over the extraoral distractors in that they improve patient acceptability and compliance during the consolidation phase because they are inconspicuous, having no external component; eliminate skin scarring caused by translation of transcutaneous fixation pins; reduce proneness to get traumatized; limit risk to neurovascular bundles (branches of facial and inferior alveolar nerves); enable invisible distraction of the mandible, thus doing away with frequent monitoring and limitation on social life [6]; and improve stability of the attachment of the device to the bone [7]. Vertical or horizontal distraction [8] of the ramus or body of the mandible respectively, or combinations of both can be accomplished by performing a corticotomy at the desired location and positioning the intraoral distractor appliance in a linear, vertical or angular direction. After a latency period of 5 to 7 days postoperatively to allow for soft tissue healing and formation of soft callus, the bones on either side of the osteotomy are slowly distracted apart at the rate of approximately 1 mm per day at a distraction rhythm of twice or thrice a day, until the desired length and contour is achieved, after which the device is left implanted for a contention period of 8 to 16 weeks, as a means of stable, neutral fixation for allowing consolidation of the bony regenerate [9]. In this way, a true three-dimensional reconstruction of the growth retarded mandible is achieved uni-or bilaterally. This treatment modality is a relatively minor surgical procedure vis-a-vis osteotomies and bone grafting procedures for maxillo-mandibular reconstruction, thus avoiding a prolonged hospital stay and permitting early return to employability. It also eliminates the necessity of bone grafts and associated donor site morbidity, need for implants and problems of incompatibility and the requirement of maxillo-mandibular fixation. As native bone is created, it enables the surgeon to have post-operative control allowing the procedure to be stopped at any point of time according to requirement of the case [10]. It also provides good long-term stability, since locally regenerated original bone is created along with appropriate neuromuscular re-adaptation and stimulation of the efficiency of the reduced functional matrix in the region, thus yielding aesthetic results that are much superior to those obtained by skeletal surgery or by soft tissue surgery done independently, or by combination of both [11]. This technique is a successful and exciting proposition in reconstructive surgery for patients with a variety of craniofacial deformities involving the jaws and dentoalveolar processes and offers new hope to patients with severe facial abnormalities without undergoing invasive surgical procedures.

CLINICO-RADIOGRAPHIC EVALUATION OF XENOGRAFTS IN MAXILLOFACIAL SURGERY.

An endeavour to find a suitable substitute for autogenous bone graft in corrections of maxillofacial deformities has been going on. Evaluation of commercially processed xenograft (SURGIBONE) has been carried out as a substitute for autogenous grafts in various maxillofacial surgical procedures in the Department of Dental Surgery at Armed Forces Medical College. Clinical and radiographic evaluation in 15 patients revealed highly satisfactory result with complete integration of the graft without any adverse host tissue reaction within the follow-up period lasting from 12-18 months.

COMPARATIVE STUDY OF BONE HEALING FOLLOWING BONE CUTS USING SURGICAL BURS AND MICROSAWS

Bone cuts on the tibia of 6 healthy dogs were studied using surgical burs and microsaws arranged in two groups by random selection to assess the speed of cutting, precision and bone healing. Bone cuts in Group A were made with surgical burs of 1.6 mm diameter using micromotor at 40,000 revolutions per minute (RPM) whereas in Group B they were created using Stryker microsaws of 0.75 mm width at the speed of 40,000 RPM. In each group, the dogs were sacrificed at the end of 8, 12 and 16 weeks and a section of the tibia containing the fracture site was removed to assess healing histopathologically. Based on clinical, radiological and histopathological examination, the results of this study indicate that microsaws have their best use in osteotomy procedures in terms of precision and thermal injury to bone whereas ostectomy procedures are more convenient with surgical burs.

ANEURYSMAL BONE CYST IN THE MANDIBLE (A Case Report)

Aneurysmal bone cyst is commonly seen in the long bones and vertebrae and is rare in the jaws. Its association with other lesions of the bone has been stressed by many workers. Because of its variable radiological appearance, diagnosis of the lesion is established by histopathological examination. A case of aneurysmal bone cyst occurring in the mandible is reported.

BONE RESPONSE TO STAINLESS STEEL AND TITANIUM BONE PLATES: An Experimental Study On Animals

ABSTRACT Various types of metallic implants have been used in the form of screws, bone plates and compression plates to achieve rigid internal fixation. In the present study, bone response to imported titanium bone plates and indigenously manufactured stainless steel bone plates, has been evaluated in dogs.Various types of metallic implants have been used in the form of screws, bone plates and compression plates to achieve rigid internal fixation. In the present study, bone response to imported titanium bone plates and indigenously manufactured stainless steel bone plates, has been evaluated in dogs.