The Applied Anatomic Study Of The Implantation Sites For Palatal Anchorage Implants

Objective The purpose of this study was to access quantitatively the vertical bone thickness and the bone density of the palate for implants placement using CBCT and dental software package,and to provide a theoretical basis for palatal implants placement for clinicians.Methods Cone-beam computed tomography(Classic i-CAT(?),Imaging Sciences International,USA)scans for maxillofacial structures were acquired in 34 orthodontic patients(11 males,23 females;mean age,24 years 2 months;range,18-35 years).The data was saved in DICOM format.Both multiplanar reformatting of obtained data and the location of the measuring sites were performed with dental software package(Ez Implant,Ewoo Vateh Group,Korea).Vertical bone height was measured at 20 palatal implantation sites.Density was measured at 10 sites with the highest percentages of measurements that could support 3.0mm length implants.SPSS 13.0 was used for statistical analysis.The 10 sites were classified with K-means cluster analysis based on the vertical bone height and bone density.Results(1)The greatest mean value of vertical bone height(8.7mm) was located at 3.0mm posterior to the incisive foramen and 6.0mm lateral to the midline.The greatest mean value of bone density(686.0HU) was located at 6.0mm posterior to the incisive foramen in the median-sagittal palate.(2)According to the cluster analysis result,the cluster 1 included the locations of 3.0mm,6.0mm,9.0mm posterior to the incisive foramen and 3.0mm lateral to the midline,and of 9.0mm posterior to the incisive foramen and 9.0mm lateral to the midline;the cluster 2 included the locations of 3.0mm posterior to the incisive foramen and 6.0mm lateral to the midline,and of 6.0mm posterior to the incisive foramen and 6.0mm,9.0mm lateral to the midline;the cluster 3 included the locations of 6.0mm,9.0mm,12.0mm posterior to the incisive foramen in the mid-sagittal regions.Both the difference in bone thickness means(P＜0.05) and density means (P＜0.05) between each group were of statistical significance.(3)The LSD result showed that the greatest mean value of vertical bone height was obtained in cluster 2,followed by cluster 1 and cluster 3;the highest bone density was founded in cluster 3,followed by cluster 1 and then cluster 2.Conclusion(1)The best sites were at 3.0mm posterior to the incisive foramen and 6.0mm lateral to the midline,and at 6.0mm posterior to the incisive foramen and 6.0mm,9.0mm lateral to the midline,with 94.1%,91.2%and 88.2%of the subjects meeting 3.0mm length implants respectively.(2)The data of median-sagittal palate showed that it was the highest bone density, and indicated it might be good for the stability in implantation.(3)An implantation site with the thickest bone and the highest density could not be found.It is suggested that clinicians should select a suitable implantation site based on the individual condition.