| Objective: By measuring the oropharyngeal airway,hyoid bone position,teeth and jaw-related indexes in adult patients with skeletal class Ⅱ hyperdivergent before and after orthodontic extraction treatment,we investigated whether the changes of teeth and jaw were related to oropharyngeal airway and hyoid bone position,and what means were taken to maintain and improve airway patency and keep hyoid bone position as much as possible during treatment to provide clear ideas in the clinic.Methods: Skeletal class Ⅱ hyperdivergent adult patients who attended the dental clinic of the Northern Theater Command General Hospital from January 2017 to December 2022 and completed orthodontic treatment by extraction of premolar teeth were selected for airway measurements,CBCT was taken before and after treatment using uniform standards,and oropharyngeal airway reconstruction was performed using Dolphin 11.8software.Cases were divided into two groups according to the change in oropharyngeal airway volume after treatment.Cases with increased oropharyngeal airway volume after treatment were included in group A.Cases with decreased oropharyngeal airway volume after treatment were included in group B.A total of 34 patients were screened,and 17 patients were in every group.Reconstruction of lateral cephalometric radiographs and measurement of hyoid bone and teeth and occlusion-related indexes were continued using Dolphin 11.8 software.SPSS 26.0 was applied for statistical processing to assess the changes in oropharyngeal airway,hyoid bone position,teeth and occlusion before and after orthodontic Treatment.Results: 1.Hyoid bone: In group A with increased airway volumes,among the three indicators measuring vertical position: H-PNS and H-MP increased compared with pre-treatment(P<0.05),H-FH showed an increased trend but was not statistically significant(P>0.05);among the two indicators measuring horizontal position: H-RGn increased compared with pre-treatment(P<0.05),H-CVP was not statistically different(P>0.05);In group B with decreased airway volumes,the three indicators measuring vertical position: H-PNS,H-FH and H-MP increased compared with pre-treatment(P<0.05);the two indicators measuring horizontal position: H-RGn and H-CVP decreased compared with pre-treatment(P<0.05),there was no statistical difference(P>0.05).In group B,the three indicators of vertical position,H-PNS,H-FH and H-MP,were all increased compared with those before treatment(P<0.05);the two indicators of horizontal position,H-RGn and H-CVP,were decreased compared with those before treatment,In the comparison between groups A and B,the three indicators measuring vertical orientation position showed a decreased trend and were not statistically significant(P>0.05);the two indicators measuring horizontal orientation position were also decreased and statistically significant(P<0.05). 2.Teeth and jaw: In group A with increased airway volumes,the occlusal plane-related indexes FH-POP angle and OP-diff angle increased compared with the preoperative period,which was statistically significant(P<0.05),and the FH-AOP angle showed an increased trend but was not statistically significant(P>0.05).The U1-NA distance,U1-NA angle,and L1-NB angle showed a statistically significant decrease(P<0.05);the U6-PP distance and L6-MP distance showed a statistically significant increase(P<0.05);the rest of the indicators were not statistically different(P>0.05).In group B with decreased airway volumes,occlusal plane-related indexes FH-AOP,FH-POP angle and OP-diff angle were increased compared with preoperative,which was statistically significant(P<0.05)).U1-NA distance,U1-NA angle and L1-NB angle showed a decreased trend,which was statistically significant(P<0.05);L6-MP distance showed a significantly increased trend,which was statistically significant(P<0.05);the rest of the indexes were not statistically different(P>0.05).In the comparison between groups A and B,the occlusal plane and teeth measurements were not statistically significant(P>0.05).Conclusions: After the orthodontic extraction treatment in female adult patients with skeletal class Ⅱ hyperdivergent,the hyoid bone generally showed a tendency to shift backward and downward;Leveling the occlusal plane during the extraction treatment of female adult patients with skeletal class Ⅱ hyperdivergent was conducive to maintain the stable position of the hyoid bone and increase the airway volume of the oropharyngeal segment;Controlling the vertical orientation of the anterior and posterior teeth,which is conducive to the level of the occlusal plane,the reverse rotation of the mandible,the facial shape improvement of skeletal class Ⅱ hyperdivergent,as well as the improvement of volume of the oropharyngeal airway. |
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