The Measurement And Analysis Of The Anatomical Structure Of The Maxillary Molar Loss Area Based On CBCT

[Objective]The residual alveolar ridge height and the residual alveolar ridge width in the maxillary molar area,maxillary sinus volume,surface area,the distance of the palatal-bottom of the maxillary sinus,and maxillary sinus wall thickness were measured and analyzed statistically.To study whether the maxillary molar loss will affect the bottom of the maxillary sinus gasification to the alveolar direction,and changing the maxillary sinus volume,the relationship between residual alveolar ridge height and width,maxillary sinus volume,surface area,the distance of the palatal-bottom of the maxillary sinus,maxillary sinus walls thickness relationship with age,sex,missing time were analyzed,which provided anatomical basis for maxillary molar plantation.[Methods]1.To collect the patients of Nanjing Stomatology Hospital,Medical School of Nanjing University which scanning CBCT in July 2014-March 2017,screening the cases which maxillary molar area had lost teeth,and missing teeth had clear time record.The age of the patients was recorded in three groups:18-40 years(youth group);41-60 years(middle-aged group);>60years(old group),recording the gender,missing teeth,missing time(divided into three groups:missing 1 year,missing 1-2 years;more than 2 years).2.To extract the CBCT data of DICOM format and select patients with suitable conditions,then reconstructing by the software of mimics17.0.The residual alveolar ridge height,residual alveolar ridge width,maxillary sinus volume,surface area,maxillary sinus mucosa thickness,lateral wall thickness of maxillary sinus,and the distance of the palatal-bottom of the maxillary sinus were measured.3.Measuring again after 2months,the average value of two measurements was taken as the final data.4.According to the inclusion criteria required by the three experiments,the experiment 1 includes 169 cases,the experiment 2 includes 47 cases,and the experiment 3 includes 55 cases,respectively.5.SPSS21.0 software was used for statistical processing of the data,and the statistical results were indicated by means ± standard deviation,and p<0.05 indicates significant difference.The differences between groups and the clinical significance of differences were analyzed.[Results]1.The RRH of the maxillary molar area was 7.11±3.41mm,and RRW was 10.18±2.57mm.The RRH of maxillary molar was 29.6%,5mm<RRH<10mm was 50.4%.2.The maxillary sinus volume without the absence side of the maxillary molar was 16139.16±7564.13mm3,and the missing side’s was 16284.72±7072.51mm3.The surface area was 4494.82±2656.70mm2 and 4162.48±1393.09mm2,respectively;the lateral wall thickness was 2.00±1.13mm and 1.83±0.90mm,respectively;the distance of the palatal-bottom of the maxillary sinus was 3.34±4.44mm and 3.64±4.35mm,respectively.3.With the missing of the the first molar of maxillary,the distance from the alveolar ridge crest to the amelocemental junction was 4.32±2.23mm in the distal and 3.26±1.65mm in the mesial.[Conclusion]1.Left or right,age,tooth missing time had no obvious effect on RRH and RRW in maxillary molar area;there was no significant difference in RRH between different genders,while RRW had significant differences,and male’s was more than female’s.The maxillary sinus mucosa thickening’s(MT>3mm)patients was 58.6%,the older patients had more chance with maxillary sinus mucosa thickening,mucosal thickening’s patients had a smaller RRH,but the maxillary sinus mucosa thickening had no obvious effect on RRW.2.The left side and right side had not significant difference in maxillary sinus volume,maxillary sinus surface area,lateral wall thickness of maxillary sinus,and the distance of the palatal-bottom of the maxillary sinus(p<0.05).The maxillary molar lost side and another side had not significant difference in maxillary sinus volume,maxillary sinus surface area,lateral wall thickness of maxillary sinus,and the distance of the palatal-bottom of the maxillary sinus(p<0.05).The missing time had not significant effect on maxillary sinus volume,maxillary sinus surface area,lateral wall thickness of maxillary sinus,and the distance of the palatal-bottom of the maxillary sinus(p<0.05).Different gender had significant differences in maxillary sinus volume,maxillary sinus surface area,lateral wall thickness of maxillary sinus,the distance of the palatal-bottom of the maxillary sinus.In general,men have larger sizes.The maxillary sinus volume and the distance of the palatal-bottom of the maxillary sinus of the youth group were larger than that of the middle-aged group and the elderly group.3.Left or right,different missing time had not significant difference in the vertical absorption degree in the distal or mesial of the maxillary first molar area after the first molar was missing.There were significant differences in the absorption degree between the distal or mesial regions of maxillary first molar,and there was more absorption in the distance.There was significant difference in the degree of absorption of the first molar distal in different genders,and there was no significant difference in the mesial.The middle-aged and the old aged group compared with the youth group had significant differences,and the younger had a smaller distance from the alveolar ridge crest to the amelocemental junction.