The Effects of Unilateral Alloplastic Temporomandibular Joint Replacement on the Opposite-Side Natural Joint: A Finite-Element Analysis.

PURPOSE: The purpose of this study was to evaluate the stress distribution on the temporomandibular joint (TMJ) prosthesis and contralateral natural TMJ with finite-element analysis. MATERIALS AND METHODS: A TMJ implant was used to create a 3-dimensional model with a computer. This model was integrated with a mandible model created with a computer by use of computed tomography images, similar to a real TMJ replacement procedure. Masticatory loads were applied to the model. The loads transmitted to the TMJ prosthesis and contralateral healthy joint were evaluated by means of finite-element analysis. RESULTS: In the model without the TMJ prosthesis, maximum von Mises stress was 252.697 N/mm2 at the condyle and 5.418 N/mm2 at the disc. In the model with the unilateral TMJ prosthesis, maximum stress at the joint prosthesis was 792.681 N/mm2. In the contralateral natural joint, maximum stress was 268.908 N/mm2 at the condyle and 8.357 N/mm2 at the disc. CONCLUSIONS: In the TMJ model with the unilateral total TMJ prosthesis, increased stress values were observed at the disc and condyle of the contralateral natural TMJ.

Graft necrosis occurred after iliac crest reconstruction after mandibular segmental resection of ameloblastoma.

Ameloblastoma is an uncommon benign odontogenic neoplasm of the maxillofacial region constituting less than 1% of tumors of the oral cavity. Ameloblastomas have been categorized broadly into 3 biologic variants: cystic (unicystic), solid, and peripheral. Unicystic ameloblastoma is a rare and less aggressive variant of ameloblastoma. The aim of this report is to describe a case of cystic ameloblastoma treated with segmental resection and iliac graft reconstruction. The possible reasons of graft failure seen in our patient at the early stage of the healing were also discussed.

Intraosseous carcinoma arising from an odontogenic cyst: a case report.

Carcinomas from an odontogenic cyst are not common, yet when they occur, squamous cell carcinomas are the most often seen. Among these cysts, the malignancy of keratocysts or dentigerous cysts are most likely. In contrast, a malignant transformation of a radicular cyst to an intraosseous carcinoma is extremely rare. In this case report, an intraosseous carcinoma arising from an odontogenic cyst in a 26-year-old male patient is presented. This case report clearly demonstrates the importance of the clinician's awareness of the malignant potential of apparently innocuous cystic lesions.

Two-year follow-up of early- and conventionally-placed two-stage implants supporting fixed prostheses.

PURPOSE: The objective of this study was to compare the biologic and prosthetic outcomes of early- and conventionally-placed implants supporting fixed prostheses. MATERIALS AND METHODS: Using inclusion/exclusion criteria, early- and conventionally-placed implant patient groups, rehabilitated with Branemark System implants supporting fixed prostheses for 2 years, were selected from the patient archives. Kaplan-Meier survival estimates, time-dependent marginal bone loss, Plaque Index, peri-implant infection, Bleeding Index scores, and prosthetic complications data of the groups were compared. RESULTS: A total of 212 implants were placed in early-placed (n=42, 101 implants) and conventionally-placed (n=45, 111 implants) patient groups and 5 implants failed during the 2-year follow-up. The 1- and 2-year Kaplan-Meier survival probabilities of early-placed (0.98) and conventionally-placed (0.973) groups were comparable (P=.735). The 6-month to 2-year marginal bone loss in the conventionally-placed group was higher than in the early-placed group (P<.05). There were differences between groups on soft tissue scores between the 2 years of function (P<.05). The frequency of prosthetic complications was very low and comparable in both groups (P=.476). CONCLUSIONS: Early- and conventionally-placed implants supporting fixed prostheses showed comparable clinical outcomes during the 2-year follow-up, although the marginal bone loss was higher in the latter group.

Descending necrotizing mediastinitis associated with an infected dentigerous cyst.

Descending necrotizing mediastinitis (DNM) is a rare condition in which an infection from the head and neck propagates into the mediastinum. The most common cause of DNM is odontogenic infection. DNM is spread by the fascial planes from the neck into the mediastinum and requires an aggressive surgical drainage through cervical and thoracic approaches. We report on a 67-year-old male patient, who had acute mediastinitis related to an infected dentigerous cyst in the left parasymphyseal region. A multidisciplinary team approach was used to treat the patient. The team consisted of thoracic surgeons, maxillofacial surgeons, and a radiologist. After the drainage of the mediastinum and pleural cavity, the cyst was enucleated. The patient was discharged at the 42nd day of hospitalization. The aim of this article is to present diagnosis, management, and follow-up of an infected dentigerous cyst that caused DNM.

Delayed Frey syndrome after closed treatment of condylar fracture.

Frey syndrome is also known as auriculotemporal syndrome and gustatory sweating. It is characterized by the occurrence of hyperesthesia, flushing, and warmth or sweating over the distribution of the auriculotemporal nerve and/or greater auricular nerve while eating foods that produce a strong salivary stimulus. It is commonly seen as a complication of parotidectomy and open surgery of temporomandibular joint. It can also be caused by other forms of trauma, including blunt trauma, but rarely does it occur without trauma. The relation between fracture displacement of the condyle and Frey syndrome adds further support to the view of the intimate anatomic relationship of the auriculotemporal nerve with the capsule of the temporomandibular joint. However, despite the proximity of these structures and the high incidence of condylar fracture (25%-36% of mandibular fractures), Frey syndrome is rare after this type of fracture. Symptoms are sometimes delayed and can be very slight; often neither the patient nor the surgeon realizes their presence. The symptoms usually appear 5 weeks to 1 year after nerve damage.In this clinical report, we presented the delayed occurrence of Frey syndrome in a patient in 6 years after closed reduction of condylar fracture. One prospective study and 11 case reports describing the development of Frey syndrome after closed treatment of mandibular condyle fractures were found in the last 4 decades. Our clinical report participates to literature as a 12th case report.

Comparison of the planimetry and point-counting methods for the assessment of the size of the mandible cysts on orthopantomograms.

OBJECTIVE: The purpose of this study is to compare the computer-assisted planimetry and point-counting methods in evaluating the sizes of the mandibular cysts with respect to their agreement and the time required to analyze. STUDY DESIGN: The surface areas of 46 mandibular cyst lesions on orthopantomograms were estimated using the point-counting and computer-assisted planimetry methods. Three observers evaluated the outlined areas twice, using the point-counting (PC) and computer-assisted planimetry (CAP) methods with an interval of two weeks. In the planimetry technique, digitalized images and ImageJ software were used to measure the surface area of the half mandibles and cysts. The grids were superimposed over the same images and the number of points hitting the interested structures was counted for the point-counting technique. The projection area fraction (PAF) of the cysts within the mandible was estimated using the obtained values by means of the two techniques. Intraclass correlation coefficient was used to assess the level of agreement between the two methods. Inter-rater reliability analysis using the Kappa statistic was performed to determine consistency among raters. RESULTS: CAP and PC techniques showed consistent intra-observer values in all observers. Intraclass correlation between CAP and PC measurements of first, second and third observers were found to be 0.9986, 0.9988 and 0.9994 respectively. The durations of PC technique was 32% higher than the CAP technique. CONCLUSION: PC and CAP methods were seemed to show sufficient agreement to be used interchangeably. The main disadvantage of the PC analysis is it takes more time than CAP method.

Use of artificial neural network in differentiation of subgroups of temporomandibular internal derangements: a preliminary study.

PURPOSE: Artificial neural networks (ANNs) have been developed in the past few decades for many different applications in medical science and in biomedical research. The use of neural networks in oral and maxillofacial surgery is limited. The aim of this study was to determine the use of ANNs for the prediction of 2 subgroups of temporomandibular joint (TMJ) internal derangements (IDs) and normal joints using characteristic clinical signs and symptoms of the diseases. MATERIALS AND METHODS: Clinical symptoms and diagnoses of 161 patients with TMJ ID were considered the gold standard and were employed to train a neural network. After the training process, the symptoms and diagnoses of 58 new patients were used to verify the network's ability to diagnose. The diagnoses obtained from ANNs were compared with diagnoses of a surgeon experienced in temporomandibular disorders. The sensitivity and specificity of ANNs in predicting subtypes of TMJ ID were evaluated using clinical diagnosis as the gold standard. RESULTS: Eight cases evaluated as bilaterally normal in clinical examination were evaluated as normal by ANN. In detecting unilateral anterior disc displacement with reduction (ADDwR; clicking), the sensitivity and specificity of ANN were 80% and 95%, respectively. In detecting unilateral anterior disc displacement without reduction (ADDwoR; locking), the sensitivity and specificity of ANN were 69% and 91%, respectively. In detecting bilateral ADDwoR, the sensitivity and specificity of ANN were 37% and 100%, respectively. In detecting bilateral ADDwR, the sensitivity and specificity of ANN were 100% and 89%, respectively. In detecting cases of ADDwR at 1 side and ADDwoR at the other side, the sensitivity and specificity of ANN were 44% and 93%, respectively. CONCLUSION: The application of ANNs for diagnosis of subtypes of TMJ IDs may be a useful supportive diagnostic method, especially for dental practitioners. Further research, including advanced network models that use clinical data and radiographic images, is recommended.

Diffuse large B-cell lymphoma with oral manifestations.

Non-Hodgkin lymphomas (NHLs) are a heterogenic group of lymphoproliferative diseases with their different behavior pattern and response to treatments. As a Hodgkin disease, NHL occurs from lymphoid tissues and can spread to other organs. Prognosis depends on histologic type, grade, and treatment. In the World Health Organization classification, aggressive B-cell lymphomas are diffuse large B-cell lymphoma, Burkitt lymphoma/leukemia, and precursor lymphoblastic leukemia/lymphoma. They may present either nodal or extranodal disease, which may be either localized or disseminated. Diffuse large B-cell lymphoma is the most common type of lymphoma in adults and is clinically, morphologically, and genetically a heterogeneous group of malignant proliferations of mature B cells, too. Diffuse large B-cell lymphoma is the most common type of NHL and accounts for about 30% of the cases. In this clinical report, we evaluated clinically and histopathologically a 64-year-old male patient who had mild pain and edema in his mandibular premolar region, and the excisional biopsy showed diffuse large B-cell lymphoma.

Horizontal alveolar distraction of the mandibular canine regions for implant placement.

Horizontal alveolar augmentation by distraction osteogenesis is an alternative method for reconstructing atrophic alveolar bone. A 65-year-old woman with atrophy of the alveolar rim in the anterior lower jaw, which had inadequate width for implant placement, was presented. Under general anesthesia, vertical and horizontal osteotomies of the buccolabial cortical bone were performed in the canine regions bilaterally. Modified horizontal distraction devices were stabilized to the mandible. Distraction proceeded from the seventh postoperative day at a rate of 0.450 mm twice a day for 6 days. After 3 months, distraction osteogenesis occurred and increased the alveolar width from 2 to 7 mm. Two implants were placed in the distracted areas. Marginal bone resorbtion around the implants was not observed 12 months after implant placement.

Fixation of vertically distracted segment with dental implants after breakage of distraction device: case report.

Distraction osteogenesis is an efficient method to augment the mandibular alveolar process for dental implants. Complications of this procedure include fracture of the basal bone, breakage of distractor, wound dehiscenses, undesirable soft tissue changes, and defective movement of the transported segment. We report a case of breakage of the distractor after mandibular alveolar vertical distraction osteogenesis. Mandibular alveolar vertical distraction osteogenesis was applied to 53-year-old woman for prosthetic rehabilitation. Fracture of the distraction device occurred on the 13th day of the activation phase. Radiographic examination revealed the fracture of the distractor rod and lingually displaced alveolar segment. Lingually displaced segment was successfully advanced to the desired position, and fixed to the basal bone using dental implants before the maturation of the distracted bone. We consider that this technique is eligible for the management of these kind of complications.

Use of a Simple Appliance to Prevent Mucosal Irritation by the Distractor Rod during Vertical Distraction: Case Report.

Patient discomfort due to the excessive length of the distractor rod is one of the disadvantages of alveolar distraction osteogenesis. Although this seems to be a minor complication, it can cause severe mucosal irritation on the opposite arch, and uncontrolled forces can lead to the loosening of the screws and the inactivation of the distractor. The purpose of this case report is to introduce an acrylic appliance that is very useful in avoiding the mucosal irritation caused by the long distractor rod. The appliance is simple, effective, and easy to fabricate.