The Clinical Research About Application Of Improved Negative Pressure Drainage Obturator In Large Cystic Lesion In Mandible

Objectives:This study investigates the effects of improved negative pressure drainage obturator in patients who have large cystic lesion in their mandible after fenestration decompression compared with common obturator,applying the digital three-dimensional technique to have comparative observation precisely.It evaluates the curative effect of vacuum drainage in large cystic lesion in mandible and explores clinical value of improved negative pressure drainage obturator in conservative treatment.Methods:1.A total of 20 patients were randomly selected from patients with large mandibular cystic lesions(cystic cavity diameter>3.5 cm)from the department of Oral Maxillofacial Surgery,Stomatological Hospital of Kunming Medical University between December 2016 to December 2017.The patients were preoperatively scanned from top of the head to hyoid by Cone Beam Computed Tomography(Brand:NewTom,Italy),and collected the data.The patients were divided into decompression group(10 patients)and negative pressure group(10 patients)by their choice.Those worn common obturator in decompression group while applied improved negative pressure drainage obturator for 6 months after the surgery.Improvement of facial deformities,CBCT data were observed and collected from all patients 1,3 and 6 months after operation.2.The DICOM data set was acquired from the CBCT and its data was imported into the Mimics 20.0 software workstation in DICOM format.Reconstructing the 3D visualization model of lesion in mandible was done by the graphic reconstruction and segmentation tool in the software,changes of cystic volume were measured and compared between preoperative,postoperative 3 months,and 6 months.Results:In the negative pressure group,the facial deformity of the patients was significantly improved at one month after operation;all patients were facial symmetric postoperative 3 months.While in the decompression group,all the malformations of the patients were alleviated slightly after one month,most patients significantly improved after the 3 months postoperatively compared with preoperatively,at the 6 months postoperatively,all patients had near symmetrical faces.Improved negative pressure drainage obturator would be faster to promote deformity patients' recovery.5 cases felt common obturator were comfortable,and 5 others felt unwell in decompression group,while all patients felt comfortable in negative pressure group.All patients considered that common obturator cleaned easily in decompression group,but in the negative pressure group only 4 cases thought improved negative pressure drainage obturator cleaned easily,the rest 6 cases also feeled discomfortly for peculiar smell.The difference between comfort and clean was statistically significant(p<0.05).Improved negative pressure drainage obturator was more comfortable than common obturator,but not easy to clean.The percentage of cyst volume changes in the negative pressure group was higher than the decompression group(t=-2.768,-2.346,p<0.05),it was more significant postoperative 3 months.Regardless of the type of obturator used,the longer the fenestration decompression time,the smaller the change in the volume of the cyst cavity.The intragroup comparison showed that there was no statistical difference between the percentage of cyst volume shrinkage and gender at 3 months and 6 months after operation in the decompression group(t=0.912,1.264,p>0.05)and the negative pressure group(t=0.476,-0.326,p>0.05).Conclusions:1.Improved negative pressure drainage obturator for facial deformity in patients with large mandibular cystic lesion shape recovery rate is more rapid than the common obturator.2.Comparing the reduced percentage of cavity volume at 3 months and 6 months after fenestration decompression,it was found that both therapies were effective when applied to large-scale mandibular cystic lesions,the volume of cystic cavity was reduced.While during the same treatment time,improved negative pressure drainage obturator has more significant clinical effect than the other group on reduction of cyst volume and new bone formation.3.Reconstructing the 3D visualization model of lesion in mandible by Mimics software,the new bone formation can be measure intuitively and accurately,it can improve the precision,reduce the error of measurement.the macroscopic observation of bone recovery,that make it possible to clinical efficacy of quantification.