Utveckling av metod för benkvalitetsmätning

Dental implant surgery is performed daily to replace single teeth and entire tooth rows. Implant selection is based on the bone quality of the cortical and trabecular bone in the jaw bone. Usually, the surgeon assesses the bone quality subjectively during drilling in the jaw bone. The aim of this project has been to increase the ability to give the surgeon a direct feedback on the bone quality during threading in a pre-drilled hole, so the right type of dental implant can be chosen. The idea of the project comes from Lennart Carlsson at TL Medical AB, who has developed a custom-made tap that is used together with a drilling machine that measures the torque during threading. Carlsson has done measurements in polyurethane foam with densities of 1050, 500 and 300 kg/m3. Through regression analyzes in MATLAB on Carlsson's measurements, a linear relationship between torque and number of turns the tap has threaded the material was found. The mean slope value of thirteen measurements/density ± SD was 8.0 ± 0.5 Ncm for density 1050 kg / m3. For density 500 kg / m3 the mean was 1.1 ± 0.2 Ncm and for density 300 kg / m3, the mean was 0.3 ± 0.1 Ncm. The relationship varied depending on which density that was investigated but the lowest achieved R2 value was 0.7. The project has resulted in a table of bone quality and maximum torque. The various ranges for maximum torques were divided into bone qualities as follows: Quality 1 ≥ 26 Ncm, 20 < Quality 2 < 26 Ncm, 12 < Quality 3 ≤ 20 Ncm and Quality 4 ≤ 12 Ncm. Own measurements in ribs from calf were performed to compare the results from the table with the reality. Five measurements out of 11 were in accordance with the table regarding bone quality while the other measurements were either one classification higher or one classification lower than the table. The most important findings are the relationship between the torque size during threading and the different material densities and that the custom-made tap produces a linearly increasing torque for each cut threading in the material. The project group realizes that more tests would have to be done, especially on human tissue, to validate the developed bone quality scale