| Background Accurate preoperative measurement for bone mass and quality of planting sites is the key to success of implant, among which bone mineral density (BMD) assessment appears especially crucial. At present CBCT is gradually applied to evaluate alveolar bone instead of CT in implant treatment. However, because of different imaging-form principal, the application of CBCT in BMD assessment is still in controversy.Objective The purpose of this study was to investigate the exact correlation of CBCT value with bone mineral density, as well as the effect of imaging volume size on bone mineral density assessment.Methods Dipotassium hydrogen phosphate (K2HPO4) solution was chosen as cancellous bone equivalent. And a series of different concentration solutions were prepared as standard density references. The K2HPO4concentrations were as follows:0,50,150,250,350,450,550,650,750,850and950mg/cm3. The solutions were scanned by CBCT at small, medium and large volume sizes. Data of CBCT values were acquired by eFilm Workstation2.0. Data analysis was performed for the correlation between concentration of K2HPO4solution and CBCT value by SPSS18.0.Results Quadratic regression model was chosen to describe the correlation between BMD and CBCT value. At small-volume size (15.24cm in diameter and15.24cm in height), the regression equation was Y=-6.84*10"4X2+1.63X+58.92(R2value was0.999). At medium-volume size (22.86cm in diameter and22.86cm in height), the regression equation was Y=-7.14*10-4X2+1.66X-156.03(R2value was0.999). At large-volume size (30.48cm in diameter and30.48cm in height), the regression equation was Y=-9.65*10-4X2+2.12X-16.25(R2value was0.999).(Y was CBCT value, X was concentration of K2HPO4solution)The results of paired samples T test showed that significant difference existed between every two volume sizes, which infered that volume size had an effect on CBCT density measurement(sig(2-tailed)<0.05). R2value of quadratic regression had no distinct difference among the three volume sizes, while stand error (SE) value raised gradually with the increase of volume size.Conclusions CBCT could be acknowledged as a reliable way of BMD assessment, on account of the significant correlation of cubic equation between CBCT value and BMD. In addition, imaging volume size makes a difference on the reliability and accuracy of BMD assessment. In our opinion, the smaller imaging volume size (diameter>10cm), the less density value variability. Background Along with the gradually wide application of dental implant．nowadaysresearches mainly focus on how to improve the implant success rate．Most viewssuggest that high dental implant primary stability is an essential of implantosseointegeration and successful treatment，especially in imlnediate loading implant．Atpresent,the innuence factors on implant primary stability still remain controversial，ofwhich the factor bone mineral density becomes a hot issue．In addition，it is believedmostly that cortical bone and cancellous bone should be studied respectively．Objective The purpose of this study was to investigate the exact statistical correlationbetween cancellous bone mineral density(CBCT value)with implant primary stability(ISQ Value)，and provide some references for dental implant design based on alveolarbone condition assessment．Materials and Methods Fresh ilia,femora,ribs and vertebrae of swine werechosen as sample bone materials，offering cancellous bone of difierent density．All the bone materials were prepared as bone blocks in regular shape，and the cortical boneshell at the implant sites were completely removed．After locating the implant sites asdesigned，the cancellous bone density at all implant sites were measured by CBCT．Subsequently a total of38dental implants(SP4.8x8mmRN，Straumann) wereimplanted at the designed sites．The implant primary stability was measured by OsstellMemor Device．Data analysis was perfornled for the correlation between canoellousbone density(CBCT value)and implant primary stability(ISQ value)by SPSS18.0．Results At small-voluirle size(15.24cm in diameter and15.24cm in height)，thereexisted significant linear correlation between cancellous bone density(CBCT value)anddental implant primary stability(ISQ value)．The regression equation of linear modelwas Y=4.84*10-2X+59.91(R~2value was O.604)．(Y was CBCT value，X was cancellousbone density)．Conclusions CBCT could be acknowledged as a reliable way to predict and estimatedentalimplant primary stability，on account of the significant linear correlation betweencancellous bone density(CBCT value)and implant primary stability(ISQ value)．... |
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