Jaw Bone Density Assessments Of Pre-implant Sites Using Spiral CT And Classify Then By Bone Quality

Purpose:To assess the bone density of oral pre-implant sites using spiral CT and simplant software,classify them by Lckholm and Zarb grouping.Methods:69 patients' jaw bone were scanned by spiral CT,scanned images were reconstructed by Simplant software.The bone density of 173 designed pre-implant sites were measured and results were recorded using Hounsfield units(HU).The data was analyzed by SPSS11.0 software and Mann-Whitney U test.classifying them by Lekholm and Zarb grouping.We analysed the relationship between bone quality and age.Results:1.The mean bone density in all implant sites was 679.96±267.70 HU.The anterior mandible mean bone density was 962.96±87.47 HU＞posterior mandible.774.07±260.34 HU＞anterior maxilla,765.71±191.28 HU＞posterior maxilla,531.52±235.94 HU. 2.We classfied jaw bone for bone classⅠ.bone classⅡ/Ⅲ,and bone classⅣ.Bone classⅣwas accounting for 21.0%in all implant sites.The CT value of bone class I was about 0-+900HU,bone classⅡ/Ⅲwas about +450-+900HU,bone classⅣwas about 0-+450 HU. 3.Bone classⅣwas least in anterior mandible and was most in posterior maxilla(P＜0.01 ).The jaw bone density was decreased according to age increasing.The bone classⅣwas increased according to age increasing.Conclusions:Anterior mandible has the highest mean bone density and posterior maxilla has the lowest mean bone density.The jaw bone density is decreased according to age increasing.We classify jaw bone by Lekholm and Zarb grouping,there are classⅠandⅡ/Ⅲin Most of the implant sites, bone classⅣaccount for a small amount of all pre-implant sites.The bone classⅣis increased according to age increasing.Spiral CT is a useful tool for determining the bone density,it is important for preoperative design and postoperative assessment.