| Summary: | 碩士 === 國立臺灣大學 === 臨床牙醫學研究所 === 96 === Objectives: ISQ readings from Osstell machine (resonance frequency analysis) have been used widely to represent the stiffness of peri-implant supporting bone and implant stability. ISQ has been related to bone height and bone quality. However, it is not clear how the cortical layer or trabecular bone contributes to ISQ and whether a bony defect neighboring to an implant affects ISQ. This study''s aim was to answer the above questions.
Material and Methods: Sawbones with 15pcf, 40 pcf and 50pcf densities were cut into blocks with different sizes respectively and combined into different assembles to represent the trabecular bone block and cortical layer. Six different groups were tested: Group A, 15pcf trabecular bone block with 50 pcf cortical layer on both sides as controlled group. Group B, 15pcf trabecular bone block with 50 pcf cortical layer on top and both sides. Group C, 40pcf trabecular bone block with 50 pcf cortical layer on top and both sides. Groups D,E,F were all made by 15pcf trabecular bone block with 50 pcf cortical layer on both sides. Group D had a defect created near the implant platform. Group E had a defect created near the midportion of implant. Group F had a defect created near the apical portion of implant. All the sample were invested with hard stone on both end to protect the sample from distortion when fixation with 10 kg force on the drilling machine. An implant (Branemark® TiUniteTM MK III 3.75x10mm , Nobel Biocare AB, Göteborg, Sweden) was screwed at the center of 40x10 mm surface of each bone block after a 3mm drilling site preparation. Each group had 5 samples. An L-shaped OsstellTM transducer was attached to the implant and each sample was tested 3 times with the transducer in M-D or B-L direction. Within the same group, nonparametric related sample test (Wilcoxon test) was performed. Nonparametric independent sample test (Mann-Whitney U test) was applied when data between two groups to detect significant difference.
Results:The results showed that significant differences between group A and B were found, but no significant different between group B and C. The direction of transducer could affect ISQ if samples with a cortical layered on top or defects appearing neighbor to the implant plateform (p< 0.05).
Conclusion: The findings suggest that cortical bone and trabecular bone contribute differently to ISQ and defects in supporting bone may affect ISQ. Further experiments are necessary to understand ISQ.
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