Three-dimensional Model Analysis Of OSAHS Patients In Long-term Treatment Of Oral Appliances

Objectives1.For the common overlapping method of digital dental model,palatal rugae overlapping method,the aim of this study was to investigate the different precision of different number of palatal rugae reference points.2.The aim of the study was to investigate the dental changes of patients with obstructive sleep apnea hypopnea syndrome in long-term treatment of oral appliances,via the method of three-dimensional model analysis.Method1.Palatal rugae overlapping method investigation: scanning ten dental models twice,and then overlapping the two digital models by palatal rugae overlapping method using three reference points,five reference points,seven reference points and nine reference points respectively.The three reference points refer to the point of intersection of incisive papilla and midline palatine suture,the mesial end point of the third palatal rugae on both sides.The five reference points refer to the point of intersection of incisive papilla and midline palatine suture,the mesial end point of the first and third palatalrugae on both sides.The seven reference points refer to the point of intersection ofincisive papillaandmidline palatine suture,the mesial end point of the first,second and third palatalrugae on both sides.The nine reference points refer to the point of intersection of incisive papilla and midline palatine suture,the mesial end point of the first,second and third palatal rugae,along with the distal end point of the third palatal rugae on both sides.2.Using Geomagic Studio 2014 software,we transferred the dental models,which were from 18 OSAHS patients before and after treatment of oral appliances,into three-dimensional models for digital analysis.Then we marked 70 reference marks in maxillar dental arch and 72 reference marks in mandibular dental arch.The information was exported as three-dimensional coordinates for later calculation and statistical analysis.Results1.Palatal rugae overlapping method investigation: scanning ten dental models twice,and then overlapping the two digital models by palatal rugae overlapping method using three reference points,five reference points,seven reference points and nine reference points respectively.Variance analysis displayed no between-group variance in the aspects of 3D positive deviation,negative deviation and average deviation.However,in maxillar dental arch,three-point group and five-point group showed statistically difference comparing with seven-point group and nine-point group while three-point group showed no statistically difference with five-point group and seven-point group showed no statistically difference with nine-point group.2.The dental changes of patients with obstructive sleep apnea hypopnea syndrome in long-term treatment of oral appliances :18 patients wearing oral appliances for 6.57±1.98 years,showed significant statistical differences in some dentition values between pre-treatment and after-treatment.The total dentition changes indicated intrusion of upper premolars,buccalization of upper posterior teeth and mesialization of lower posterior teeth.Also,it demonstrated decrease in upper dental arch length,increase in upper posterior arch width and decrease in upper arch depth.Moreover,it suggested dramatic reduction of overjet in front teeth.In the same time,other values evaluated showed no significant change before and after treatment of oral appliances.Conclusion1.Palatal rugae overlapping method investigation: seven-point palatal rugaeoverlapping and nine-point palatal rugae overlapping method are more accurate than three-point and five-point method.Since seven-point palatal rugae overlapping and nine-point palatal rugae displays no difference,we may choose the seven-point palatal rugae overlapping method to acquire accurate model overlapping results.2.Long-term wearing oral appliances results in changes in several variables of dental occlusion,which should be not be ignored for dentists conducting this treatment plan.However,the side effect of dental occlusion changes is little on a whole,leading to high security in this aspect.