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| Author(s): |
Érica Cristina Marchiori
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Faculdade de Odontologia de Piracicaba |
| Defense date: | 2010-08-10 |
| Examining board members: |
Roger William Fernandes Moreira;
Cecília Luiz Pereira Stabile;
José Ricardo de Albergaria Barbosa
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| Advisor: | Roger William Fernandes Moreira |
| Abstract | |
The face-bow is indicated to obtain the inclination of the occlusal plane in two-jaw surgeries before mounting the casts on the semi-adjustable articulator (SAA). However, there are many scientific data which shows inaccuracy of the face-bow transference when the inclination of the maxilla is compared on the articulator and on lateral cephalometric radiographs. This implies the Frankfurt horizontal plane is not parallel to the upper arm of the SAA. The aim of this study was to evaluate whether a 6° counterclockwise change in occlusal plane inclination would produce significant modifications on the final result of a maxillary impaction and mandible advancement model surgery. Four groups were used in this study. Each group had 10 identical maxillary casts mounted on the SAA and one mandibular cast. All groups were mounted on the SAA with vertical maxillary excess and mandibular retrognathism, with 6 millimeters of overjet and one millimeter of overbite, without asymmetry. The maxillary casts of the two control groups were mounted with an inclination of 13° of the occlusal plane, while the maxillary casts of the two study groups were mounted with an inclination of 7° of the occlusal plane. Two different impactions were tested, an impaction of six millimeters and an impaction of 10 millimeters. With the aid of the Erickson platform, preoperative measures of the casts were performed according to the method described by Ellis III (1990). To control the movement of the maxilla during model surgery, another two maxillary and mandibular casts were mounted on the SAA using the same references of the control group. These two SAA were used for splint fabrication. One splint for an impaction of 6 mm and another for an impaction of 10 mm. These splints were used in the study groups to simulate the proposed movement. The final measures of the maxillary casts after impaction were obtained using the Erickson platform. The results of control and study groups were compared using the t-test. There were no statistical differences between control groups and study groups in the vertical and latero-lateral movements of the models. The antero-posterior movement of the upper incisor was statistically significant for both study groups. In the 6 millimeter impaction group the mean difference was 0,48 millimeters (p<0.05) and in the 10 millimeter impaction group the mean difference was 0,94 millimeter (p<0.05). In conclusion, mistakes in cast mounting on the SAA may produce a retruded final of the operated maxillary casts. Although statistically significant, the values are small to produce differences in the final clinical result. (AU) | |