ABSTRACT
OBJECTIVES: To estimate the optimal bending angles in the running loop for mesial translation of a mandibular second molar using indirect skeletal anchorage and to clarify the mechanics of tipping and rotating the molar. METHODS: A three-dimensional finite element model was developed for predicting tooth movement, and a mechanical model based on the beam theory was constructed for clarifying the force systems. RESULTS: When using a running loop without bends, the molar tipped mesially 14.4° and lingually 0.6°, rotated counterclockwise 4.1°, and the incisors retracted 0.02 mm and intruded 0.05 mm. These angles were about the same as those estimated by the beam theory. When the amount of tip back and toe-in angles was 11.0°, mesial translation of the molar was achieved, and incisors retracted 0.10 mm and intruded 0.30 mm. CONCLUSIONS: Mesial translation of a mandibular second molar without any significant movement of anterior teeth was achieved during protraction by controlling the tip back and toe-in angles and enhancing anterior anchorage with the combined use of a running loop and indirect skeletal anchorage.
Subject(s)
Mandible , Molar , Orthodontic Anchorage Procedures/methods , Tooth Movement Techniques/methods , Computer Simulation , Dental Stress Analysis , Finite Element Analysis , Humans , Mesial Movement of Teeth , Models, Dental , Radiography, Panoramic , Stress, Mechanical , Tomography, X-Ray ComputedABSTRACT
Ovarian yolk sac tumor (YST) is a malignant ovarian neoplasm differentiated from primordial germ cells that occur in young age, while endometrioid carcinoma (ECA) is a müllerian epithelial tumor that usually occurs in older patients. The coexistence of an ovarian ECA and YST component is very rare. Only 12 cases have been reported until now according to a Medline search of the English literatures. We present a case of a simultaneous ECA and a YST component in a 35-year-old woman. Exploratory laparotomy was performed. The parts of both ovaries that showed an endometrioid-like glandular pattern were positive for cytokeratin 7 and negative for AFP, but the YST component was negative for cytokeratin 7 and positive for AFP. After completion of four courses of BEP chemotherapy, two courses of taxane and carboplatin chemotherapy were added. The patient failed to respond and succumbed to the disease after 12 months of follow-up.
