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W Tharanon

Publications and source records attributed to W Tharanon.

14 recordsLinked to original sources
PubMed2000

Tension forces in relation to LeFort III osteotomies.

Complications associated with LeFort III osteotomies have led to modifications of the procedure. Attempts to decrease morbidity include performing incomplete osteotomies or eliminating pterygomaxillary dysjunction. The purpose of this study was to determine the amount of tension required for separation of the midface from the pterygoid plates and to observe the fracture patterns. An Instron machine (Instron Corporation, Canton, MA) was used to measure the tension forces in 16 cadaver skulls divided into five groups. The groups varied as to whether the osteotomies were complete and whether pterygomaxillary separation was performed. Specimens with incomplete osteotomies and without pterygomaxillary separation required greater tension forces for separation and exhibited a high percentage (47%) of unfavorable fractures. Because high amounts of tension are required leading to unpredictable separations, we recommend complete osteotomies with pterygomaxillary dysjunction when performing LeFort III osteotomies.

Dental Stress Analysis↗
PubMed1999

Mandibular distraction osteogenesis with multidirectional extraoral distraction device in hemifacial microsomia patients: three-dimensional treatment planning, prediction tracings, and case outcomes.

Distraction osteogenesis of the craniofacial skeleton with the use of several different types of distraction devices (i.e., extraoral, intraoral, unidirectional, multidirectional, and customized) have been documented. However, the details of treatment planning and the method of predicting the distraction of the mandible in patients with hemifacial microsomia have not been published previously. This paper presents a technique for (1) three-dimensional treatment planning for mandibular distraction, (2) three-dimensional prediction tracings with conventional radiographs (panoramic, lateral, and posterior-anterior cephalometric), and (3) correlating the treatment planning and clinical applications. Lastly, 2 patients with hemifacial microsomia planned and treated with this approach are reported.

Adolescent↗
PubMed1999

Transoral maxillary distraction osteogenesis of an unrepaired bilateral alveolar cleft.

Distraction osteogenesis has gained acceptance as a viable modality for lengthening hypoplastic skeletal structures in the maxillofacial region. A case of the application of this technique to advance the maxilla in an unrepaired bilateral alveolar cleft via a transoral approach is presented. The distraction devices were applied bilaterally to the zygomatic buttress region with the activating arms protruding from the oral cavity. A high Le Fort I osteotomy was performed under general anesthesia and, prior to distraction, the three maxillary segments were unified with an occlusal acrylic splint. Activation was begun 6 days after placement, at a rate of 1 mm per day, until the planned maxillary advancement had been achieved. An 8-week period of consolidation was allowed prior to removal of the devices.

Alveoloplasty↗
PubMed1998

Comparison between the rigidity of bicortical screws and a miniplate for fixation of a mandibular setback after a simulated bilateral sagittal split osteotomy.

PURPOSE: This investigation compared the biomechanical stability of three bicortical screws with that of a single four-hole miniplate after 5-mm mandibular setback after a bilateral sagittal split osteotomy (BSSO) in cadaver mandibles. MATERIALS AND METHODS: Thirty human cadaver hemimandibles underwent BSSO followed by two different rigid fixation techniques. All specimens had no third molar, bony pathology, or evidence of mandibular fracture, and there was no history of renal disease or hyperparathyroidism. The specimens were randomly divided into two groups. In group I, three bicortical screws were placed at the superior border, and in group II, one four-hole miniplate was secured on the external oblique ridge with four monocortical screws. The bony height of the mandible was recorded. Maximum resistance load (MRL), the greatest load recorded just before a sudden decrease in load level (bone or fixation failure), was recorded when the mandibles were tested in a compression machine. Multiple regression analysis was used to evaluate the differences in bone height and the MRL between groups I and II. RESULTS: The mean bone height in groups I and II were 28.64 +/- 2.50 mm and 28.72 +/- 4.08 mm, respectively. The mean MRL in group I (20.49 +/- 7.22 kg) was greater than in group II (17.41 +/- 7.81 kg). The multiple regression analysis showed no significant difference in the bone height and the MRL between group I and group II (beta = 2.3492, P = .4114). CONCLUSION: There was no statistically significant difference in stability provided the two techniques.

Adult↗
PubMed1998

Surgical outcomes using bioabsorbable plating systems in pediatric craniofacial surgery.

The purpose of this study was to evaluate the surgical outcomes of the 1.5-mm LactoSorb plating system (Walter Lorenz Surgical, Inc., Jacksonville, FL, U.S.A.) used to stabilize the osteotomized calvarial bone in pediatric patients who have undergone craniofacial surgery. The records of 33 consecutive pediatric patients who underwent craniofacial surgery from January 1997 through December 1997 were reviewed. There were 18 male and 15 female patients, and the age ranged from 4 months to 12 years. Patients were followed-up at 1 week, 1 month, 3 months, 6 months, and 12 months after surgery. For those patients reviewed, the following information is included: age, sex, diagnosis, surgical procedures, number and size of LactoSorb plates and screws used in each patient, operative difficulty of the screws and the heat pack, and postoperative complications, including wound healing, palpability, and infection. The LactoSorb plating system was used to stabilize the osteotomized calvarial bones in 33 patients who were diagnosed with: 1) craniosynostosis, 2) hydrocephalus, 3) fibrous dysplasia, or 4) cranial deformation. Orbital rim advancement and anterior cranial vault reshaping were performed in 17 patients. Posterior cranial vault reshaping, orbital rim advancement, and anterior cranial vault reshaping were performed in eight patients. Posterior cranial vault reshaping only was performed in seven patients. Excision of fibrous dysplasia from temporal bone was performed in one patient. One patient had a postoperative wound infection, and LactoSorb plates were palpable postoperatively in four patients. The LactoSorb plating system provided adequate rigidity for stabilizing the osteotomized calvarial bone during surgery and maintained adequate rigidity after surgery during the bone healing period before absorption. This plating system showed satisfactory results in pediatric craniofacial surgery patients.

Absorbable Implants↗
PubMed1992

Accuracy of face-bow transfer: effect on surgical prediction and postsurgical result.

One of the most common errors in model surgery for orthognathic surgery is in the mounting of the models on the articulator. This study assessed the ability of one type of face-bow to transfer the maxillary model to the articulator. Twenty-five consecutive mountings were evaluated by calculating the angle made between the maxillary occlusal plane on the cephalogram and comparing it with the maxillary occlusal plane angle on the articulator. An accurate face-bow transfer should transfer this angle, making the two similar. It was found that a significant difference between the maxillary occlusal plane angle on the cephalogram and the articulator was found in the average case. The implications of such errors and a technique to avoid them are presented.

Cephalometry↗
PubMed1990

The modified superior based pharyngeal flap. Part III. A retrospective study.

A retrospective study of 31 patients who had diagnosed velopharyngeal incompetence and were surgically managed with the modified superior based pharyngeal flap was completed. The following were analyzed: age at time of operation, gender, physical status, diagnostic protocol, length of operation (length of total surgery) and length of superior based pharyngeal flap, length of postoperative hospital stay, length of total hospital stay, length of follow-up, speech results, complications, patient care, and medication. The result showed that the optimal timing for correction of velopharyngeal incompetence was between 3 and 6 years of age. The mean length of total hospital stay was 2.7 days, postoperative complications were minimal, and speech results were generally good.

Adolescent↗
PubMed1990

A precise radiographic method to determine the location of the inferior alveolar canal in the posterior edentulous mandible: implications for dental implants. Part 1: Technique.

In severely atrophic or osteoporotic mandibles, the location of the inferior alveolar nerve may vary considerably, both superoinferiorly and mediolaterally. A clinician's ability to reliably locate this nerve within the mandible would permit the surgical planning of implant placement in the posterior edentulous mandible. Eight edentulous cadaver mandibles were studied. A technique that precisely locates the inferior alveolar nerve within the mandible is described. The technique will aid the surgeon in planning a surgical approach to the posterior mandible with reduced risk of injury to the inferior alveolar nerve.

Adult↗
PubMed1990

A precise radiographic method to determine the location of the inferior alveolar canal in the posterior edentulous mandible: implications for dental implants. Part 2: Clinical application.

An analysis of implant placement in the posterior region of eight edentulous cadaver mandibles was performed. The results demonstrated that the radiographic technique developed can be employed to safely place implants adjacent to the inferior alveolar nerve in the posterior mandible by using radiographic laminography and a specially designed intraoral reference splint.

Adult↗