Finite element analysis of biplanar customized reconstruction plates for lateral and central segmental defects of mandible.

The purpose of this study is to compare biplanar custom mandibular reconstruction plates with locking reconstruction plates in bridging central and lateral mandibular segmental defects by using the finite element method. Central and two different types of lateral segmental defects were created on mandibular model that was generated from computed tomography of a male patient. Segmental defects were fixed with conventional locking reconstruction plates and two different custom designed plates with caudobuccal and dorsobuccal cover. Stress formation on hardware and screws, strain on bone under masticatory simulation were evaluated with a finite element model. The stress values on plate and screws were higher in conventional reconstruction plate than custom plates. Simulations of central segmental defect revealed maximum von Mises stresses of 643.62 MPa and 101.83 MPa in conventional reconstruction plate and biplanar plate, respectively. Biplanar plates revealed slightly higher von Mises stresses than extended surfaced biplanar plates. The screws close to resection area were exposed to higher stress than farther screws for whole groups. In conventional reconstruction plate, the maximum von Mises stress values of fixation screws were 268.66 MPa and 95 MPa for central segmental defect and lateral segmental defect, respectively. The study reveals that the biplanar custom reconstruction plates had a favourable effect on stress distribution and can enhance function and aesthetics as supporting mandible and flaps from two different planes.

Prosthetic Rehabilitation of Partial Ear Defect: 2 Case Reports.

The loss or absence of an auricle may result from trauma, disease or congenital anomalies and causes a considerable aesthetic problem. If the deformity involves the external auditory canal, it can affect hearing. This case report describes the surgical and prosthetic treatment of two patients with partial defects of their right external ears from different causes. Implant-retained auricular prostheses fabricated from heat-temperature-vulcanised silicone were used in both the cases; they were designed to be harmonious with the remaining tissues. The patients experienced improved retention, aesthetics, hearing and quality of life with these prostheses. During the approximately 3 year follow-up, both the prostheses were re-fabricated once; however, problems related to implant stability and peri-implant tissue health were not encountered.

Distracted mandible does not reach the same strength as normal mandible in rabbits.

OBJECTIVE: The aim of this study was to determine the resistance and fracture strength values of the bone with the use of biomechanical tests in different consolidation periods of mandibular distraction osteogenesis. STUDY DESIGN: In this study, 21 mature male New Zeland rabbits were used. After distraction, rabbits were separated into 3 groups to experience 4, 8, and 12 weeks' consolidation periods. Nonoperated hemimandibles of 6 rabbits were used as a control group. After 5 days' latency period, 0.5-mm distraction was applied twice a day, i.e., 1 mm/d lengthening. After the 5-mm lengthening application, we left the animals for 1, 2, or 3 months of consolidation period. Bending stress and strength values of the bone at fracture point were measured with the use of a 3-point bending test. RESULTS: There were significant differences between the control and 3 study groups regarding bending stress and strength values. In addition, each study group was significantly different from each other. CONCLUSIONS: Bending stress and fracture strength of the bone may not reach that of normal bone after completion of 3 months' consolidation. It should be considered to keep in place extraoral appliances or comfortable intraoral distractors for a long period.

Comparison of depth of anesthesia in different parts of maxilla when only buccal anesthesia was done for maxillary teeth extraction.

Objective. Recently, some authors reported that maxillary teeth could be extracted without using palatal anesthesia, but they did not clearly specify the extracted teeth. This is important, because apparently the local anesthetic solution infiltrates the maxilla and achieves a sufficient anesthesia in the palatal side. Thus, thickness of the bone may affect the depth of anesthesia. The aim of this study was to compare the depth of anesthesia in different parts of the maxilla when only a buccal infiltration anesthesia was done. Patients and Method. The maxilla was divided into anterior, premolar, and molar regions. In each region, 15 teeth were extracted with a single buccal infiltration. The patient marked the pain level on a numerical rating scale. Results. Anesthesia depth was sufficient and was not significantly different (P > 0.05) among three maxillary regions. Conclusion. Except for surgical interventions, all maxillary teeth can be extracted using only a buccal infiltration anesthesia.

Complex midfacial reconstruction with an implant-supported framework.

This clinical report describes the treatment of a patient with osseointegrated extraoral implants supporting a framework retainer and acrylic resin mesostructures and a large silicone midfacial prosthesis. A metal framework was used to splint the implants together and provided satisfactory retention for the facial prosthesis. A 2-piece prosthesis that composed of an obturator and facial prosthesis was fabricated. Cosmetic improvements as well as the ability to speak, swallow, and, to a lesser degree, chew, were achieved for this patient.

Comparison of three pain scales after impacted third molar surgery.

OBJECTIVE: Recently, a pain assessment scale called "full cup test" (FCT) has been suggested for pain evaluation. It is claimed to be easier to use for the patient, and it allows using parametric tests for statistical analyses. The aim of this study was to evaluate the validity of the FCT in third molar surgery. STUDY DESIGN: The FCT was compared with 2 well accepted pain scales. Forty-eight patients who had fully impacted lower third molars were included. All patients were asked to fill 3 pain scales--visual analog scale (VAS), verbal rating scale (VRS), and FCT--daily during the first postoperative week. Then the scales were collected and data statistically analyzed. Agreement among VAS, VRS, and FCT was evaluated using the Spearman rank coefficient. RESULTS: Correlations among 3 scales were very high and significant (P < .001). CONCLUSIONS: The FCT can be used to assess the postoperative pain after third molar surgery.

Marsupialization of unicystic ameloblastoma: a conservative approach for aggressive odontogenic tumors.

Unicystic ameloblastoma (UA) is known as a distinct entity which has a less aggressive behavior when compared with conventional ameloblastoma. In this report, we have presented two cases of UAs, (of which one case showed a more aggressive behavior with mural invasion into the adjacent tissues and granular cell differentiation), both of which were successfully managed with enucleation following marsupialization. We aim to highlight how this method can be used for the successful management of such cases, rather than following more aggressive approaches. In both the cases, marsupialization was done for the UA lesions initially and follow-ups were maintained. When the tumor size had regressed on radiographic follow up, an enucleation procedure with ostectomy of the margins was carried out. Special importance was also given to the endodontic treatment of the teeth involved in the area of the lesion. The patients were free of the condition and did not show any signs of recurrence on radiographic follow-ups even after 30 months of the final procedure. Granular variant of UA is quite rare and had been considered to be more aggressive. Marsupialization of UA is an alternative treatment option of resection even for more aggressive variants, as long as the histological behavior of the lesion was carefully evaluated and strict radiographic follow-up is maintained.

Treatment of localized Langerhans' cell histiocytosis of the mandible with intralesional steroid injection: report of a case.

Localized Langerhans cell histiocytosis (LLCH), formerly known as eosinophilic granuloma, mainly affects the skull, mandible, vertebrae, and ribs in children and the long bones of adults. Symptoms range from none to pain, swelling, and tenderness over the site of the lesion. General malaise and fever occasionally are present. Radiographically, lesions appear as radiolucent areas with well demarcated borders. LLCH may resolve spontaneously after biopsy in a period of months to years. However, if features include continuous pain, decrease of function, pathologic fractures, migration and resorption of teeth, or rapid progression, then active treatment needs to be considered. Treatment approaches include surgery, radiotherapy, chemotherapy, and intralesional injection of corticosteroids. In children with mandibular LLCH, 1 dose of methyprednisolone succinate injection has proven to be adequate. However, injections have not been performed in cases involving pathologic fracture. We report a new case of LLCH of the mandible that caused a pathologic fracture in an adult patient. Repeated intralesional corticosteroid injections resulted in fracture line disappearance within 14 months and lesion healing by the end of the 36-month follow-up.

Evaluation of osteoblastic activity around dental implants using bone scintigraphy.

OBJECTIVES: The aim of this study was to evaluate the osteoblastic activity around delay-loaded intraosseous dental implants using nuclear medicine imaging techniques. MATERIAL AND METHODS: Seven totally edentulous patients (two females and five males, between 48 and 57 years of age) were included in the study. Two implants were inserted into mandibular canine regions and removable prostheses were produced after 3 months. Whole-body bone scintigraphies with 20 mCi technetium 99m labelled methylene diphosphonate were taken from the patients before implant insertion, 3 months after implant placement just before the prostheses were made and 1 year after implant placement. Standardized count/pixel (SC/P) rates were calculated for each patient. Preimplantation SC/P values were compared with the 3- and 12-month values. Three-month values were compared with the 12-month values as well. RESULTS: SC/P rates in the third month were significantly higher (P<0.05) than preoperative values and the SC/P rates of the 12th month were significantly lower (P<0.05) than 3-month values. The SC/P rates of the 12th month were relatively higher than first scintigraphies but the difference was insignificant (P>0.05). CONCLUSIONS: Within the limitations of this study, in which delayed loading was applied, we showed that osteoblastic activity persisted more in delay loaded implants than immediate and early loading. After 1 year, there was no cellular activity around two implants and this implied that two implants were sufficient for a total prosthesis.

Conservative Treatment Protocol for Keratocystic Odontogenic Tumour: a Follow-up Study of 3 Cases.

BACKGROUND: The keratocystic odontogenic tumour is classified as a developmental cyst derived from the enamel organ or from the dental lamina. The treatment of keratocystic odontogenic tumour of the jaw remains controversial. The aim of this study was to report the outcome of our conservative treatment protocol for keratocystic odontogenic tumour. METHODS: Three patients with different complaints referred to Oral and Maxillofacial Surgery Clinic, Faculty of Dentistry, Selçuk University. Initial biopsy was carried out in all patients and keratocystic odontogenic tumours was diagnosed subsequent to histopathological examination. The patients with keratocystic odontogenic tumours were treated by enucleation followed by open packing. This conservative treatment protocol was selected because of existing young aged patients. The average follow-up duration of the cases was 2 years. RESULTS: Out of 3 cases, 2 lesions were present in mandible and 1 lesion in maxilla. There was no evidence of recurrence during follow-up. All the cases were monitored continuously with panoramic radiographs, computed tomography and clinical evaluations. CONCLUSIONS: This conservative treatment protocol for keratocystic odontogenic tumours, based on enucleation followed by open packing would be a possible choice with a view of offering low recurrence rate and low morbidity rate particularly in young patients.

Correction of Mandibular Retrognathia and Laterognathia by Distraction Osteogenesis: Follow up of 5 cases.

This article evaluates the use of distraction osteogenesis in the treatment of mandibular retrognathia and laterognathia and the long term treatment results of the patients treated with this technique. The procedure was carried out in 5 subjects (3 males and 2 females, mean age 18.4 years) aged between 14 years and 27 years. In patients treated with bilateral mandibular distraction, it was observed that the ANB angle decreased by a mean of 5 degrees , the mandibular corpus length increased by a mean of 14.5 mm and the overjet decreased by a mean of 12.2 mm after treatment. In patients treated with unilateral mandibular distraction, a mean of 3.5 degrees reduction was achieved in ANB angle, the mandibular corpus length increased by a mean of 5.5 mm and a mean of 7 mm correction was achieved in relation to craniofacial midline with treatment. One of these patients showed an increase of 10 mm in ramus height on the affected side and a decrease of 5 degrees in gonial angle whereas the other one showed an increase of 12.5 degrees in gonial angle and an increase of 11 mm in ramus height on the affected side after treatment. The most significant long term relapse was observed in one of the patients treated with bilateral mandibular distraction. Long term relapse seen in the rest of the patients was within clinically acceptable limits. It can be concluded that distraction of the deformed mandible is a feasible and effective technique for treating mandibular retrognathia and laterognathia. However, it must be borne in mind that accurate placement of the distractors and determining the correct distraction vector are crucial factors that have an influence on long term clinical success.

Comparison of two different approaches to the pterygomaxillary junction in Le Fort I osteotomy.

OBJECTIVE: The purpose of this study was to compare the damage before and after down fracture in Le Fort I osteotomies performed with and without the separation of pterygomaxillary junction using curved osteotomes in a cadaver model. STUDY DESIGN: The study sample comprised 6 cadavers aged between 55 and 70 years (mean age: 63.8 years). Three cadavers were partially edentulous, 2 cadavers still maintained a full complement of teeth and 1 cadaver was edentulous. Le Fort I osteotomy was performed on all cadavers. Pterygomaxillary osteotomies were only performed on the right sides whereas the left sides were left intact. Subsequently, the maxilla was mobilized by applying digital pressure on the anterior maxillary segment. Computed tomography scans of each specimen were obtained before surgery, after surgery-before down fracture and after down fracture to document secondary fractures. RESULTS: Before the down fracture, secondary fractures were found in only 1 specimen (right side), whereas after the down fracture, secondary fractures were found in 5 specimens by CT. After the down fracture, the rate of occurrence of secondary fractures was 62% in the right side and 38% in the left side. CONCLUSION: With respect to the results of the present study, the use of osteotomes for pterygomaxillary dysjunction increases the incidence of fractures in maxillary osteotomy. However, the occurrence of almost all fractures subsequent to down fracture suggests the presence of possible bony splits that could not be diagnosed by radiographic examination immediately after maxillary osteotomy may have become apparent or transformed into fractures following down fracture.

Superoxide dismutase and glutathione peroxidase enzyme activities in larynx carcinoma.

CONCLUSIONS: It can be concluded that these changes are related to damage at the DNA level or to the inhibitory effects of tumor promoters. Increases in GSH-Px activities may be related to the independence of this enzyme from the suppressive effects of tumor promoters. This study and others in the literature show that it is not possible to generalize the activities of SOD and GSH-Px in cancer. OBJECTIVE: There has been growing interest in the role of free radicals as a cause of cancer. It has been suggested that an increase in activated forms of oxygen in cells due to overproduction and/or the inability to destroy them may lead to severe damage of cell structures. As a result of these changes, some chromosomal aberrations and carcinogenesis may develop. Superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) are two important antioxidant enzymes involved in enzymatic antioxidant defense mechanisms. To our knowledge there have been no previous studies in the literature investigating the activities of SOD and GSH-Px in laryngeal cancer. MATERIAL AND METHODS: The study subjects comprised 10 male patients (age range 43-76 years) with laryngeal carcinoma and 10 healthy controls (4 males, 6 females; age range 40-69 years) with intraoral hyperplastic fibrous tissue. Homogenate SOD and GSH-Px activities were measured using commercially available kits. RESULTS: GSH-Px levels were significantly increased in the cancerous tissues compared with cancer-free adjacent tissues and fibrous hyperplasia tissues (p < 0.05), whereas there was no significant difference between SOD activities (p > 0.05). There was also no significant difference between GSH-Px activity in cancer-free adjacent tissues and fibrous hyperplasia tissues (p > 0.05).

Intraosseous screw-supported upper molar distalization.

The aims of the present study were to investigate (1) the efficiency of intraosseous screws for anchorage in maxillary molar distalization and (2) the sagittal and vertical skeletal, dental, and soft tissue changes after maxillary molar distalization using intraosseous screw-supported anchorage. Twenty-five subjects (18 girls and seven boys; 11.3 to 16.5 years of age) with skeletal Class I, dental Class II malocclusion participated in the study. An anchorage unit was prepared for molar distalization by placing an intraosseous screw behind the incisive canal at a safe distance from the midpalatal suture following the palatal anatomy. The screws were placed and immediately loaded to distalize upper first molars or the second molars when they were present. The average distalization time to achieve an overcorrected Class I molar relationship was 4.6 months. The skeletal and dental changes were measured on cephalograms and dental casts obtained before and after the distalization. In the cephalograms, the upper first molars were tipped 8.8 degrees and moved 3.9 mm distally on average. On the dental casts, the mean distalization was five mm. The upper molars were rotated distopalatally. Mild protrusion (mean 0.5 mm) of the upper central incisors was also recorded. However, there was no change in overjet, overbite, or mandibular plane angle measurements. In conclusion, immediately loaded intraosseous screw-supported anchorage unit was successful in achieving sufficient molar distalization without major anchorage loss.

Desmoplastic ameloblastoma in the mandible.

The desmoplastic variant of ameloblastoma (DA) is characterized by unique histological and radiographic features. It is histologically characterized by an abundance of densely collagenous stroma with small nests and strands of likely compressed odontogenic epithelium. Although radiographic examination of ameloblastomas usually reveals unilocular or multilocular radiolucency, DA may appear as a mixed radiopaque-radiolucent lesion. In this case report, a 68-year-old man who had a complaint of a mass in his right mental region is presented. The patient was unable to wear his prosthesis because of an underlying swelling. An incisional biopsy was performed. Microscopic examination of the surgical specimen revealed large epithelial islands of ameloblast-like cells within increased, dense, collagenous desmoplastic stroma. Histopathologically, it was diagnosed as DA. Under local anesthesia, the lesion was enucleated. There was no recurrence after 32 months of follow-up.