ABSTRACT
Objective:
To evaluate the pharyngeal airway and maxillary sinus volume changes after mandibular setback surgery combined with maxillary advancement and/or impaction surgery.
Materials and Methods:
Seventeen Class III skeletal patients (11 females, 6 males) who required bimaxillary orthognathic surgery were selected. Volumetric measurements were performed using cone beam computed tomography (CBCT) scans preoperatively and 3.9 ± 0.87 months postoperatively. All the CBCT scans were assessed and analyzed using MIMICS 14.0 software. Preoperative and postoperative volumes of pharyngeal airway and maxillary sinuses and the relationship between the amounts of surgical movement of the jaws and the above volumes were statistically evaluated.
Results:
The pharyngeal airway area presented no significant change except for the lower and total pharyngeal airway volumes in males, in whom a significant decrease was observed (4196.27 ± 2061.11 mm3 and 3375.53 ± 3624.67 mm3, respectively). No significant change was observed in the minimal cross-sectional area of the pharyngeal airway. There was a significant decrease in the volume of the maxillary sinuses after the surgery by 3448.09 ± 3315.56 mm3. No correlation was found between the amount of skeletal movement and the change in the volume of pharyngeal airway or maxillary sinuses.
Conclusion:
There was a significant decrease only for lower and total pharyngeal airway volumes in males and a significant decrease in the volume of the maxillary sinuses.
Low temperature scanning electron microscopy (LTSEM) has been evaluated with special reference to its application to the study of morphology and development in microorganisms. A number of criteria have been considered and have proved valuable in assessing the standard of results achieved. To further aid our understanding of these results, it has been necessary to compare those obtained by LTSEM with those from more conventional preparatory procedures such as 1) chemical fixation, dehydration and critical point-drying; 2) freeze-drying with or without chemical vapour fixation before hand.The criteria used for assessing LTSEM for the above purposes are as follows:
1)Specimen immobilization and stabilization2)General preservation of external morphology3)General preservation of internal morphology4)Exposure to solvents5)Overall dimensional changes6)Cell surface texture7)Differential conformational changes8)Etching frozen-hydrated material9)Beam damage10)Specimen resolution11)Specimen life
Abstract
INVAR is a 36% nickel-iron alloy having the lowest coefficient of expansion, recommended for applications requiring no dimensional changes with temperature variations. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on low and high temperature performance, and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Fe-24. Producer or source: Carpenter.
Abstract
Deutsche Edelstahlwerke Cryodur 2067 is a high-carbon, 1.5% chromium, alloy cold-work tool steel. In view of its higher hardenability than that of the non-alloy, water-hardening, cold work tool steels, this steel can be oil quenched, a factor that minimizes dimensional changes during quench hardening. Cryodur 2067 is suitable for short run tooling in applications requiring high surface hardness. This datasheet provides information on composition, physical properties, hardness, and elasticity. It also includes information on forming, heat treating, and machining. Filing Code: TS-786. Producer or source: Deutsche Edelstahlwerke Specialty Steel.
Applicability of Multiple Linear Regression Analysis to the Analysis of Three-dimensional Changes in Perioral Soft Tissue Following Mandibular Setback Surgery
