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OBJECTIVE@#To provide the basis for the clinical development of ultrasonic shoulder preparation by comparing the roughness and three-dimensional topography of shoulder surface between ultrasonic instruments and conventional rotary instruments, to make preliminary suggestions for clinical use of ultrasonic instruments.@*METHODS@#(1) Four areas of buccal and palatal surfaces of six extracted human premolars were prepared with different grit size of rotary instruments. Polyether was used to take impression of the shoulder area, 3-D topography measurement laser microscope (3-D TMLM) was used to scan the impressions and compare the shoulder surface roughness of the four areas. (2) Six extracted human premolars were prepared, mesial half of the shoulder was finished with traditional rotary instruments and distal half with ultrasonic instruments. Polyether was used to take impression of the shoulder area, 3-D TMLM was used to scan the impressions and compare the shoulder surface roughness and 3-D topography, and the shoulder surface morphology was observed by surgical microscope (×25 magnification). (3) Twenty extracted human maxillary symmetrical homonymous anterior teeth were poured into die stone using artificial gingiva, ultrasonic instruments group and rotary instruments group were divided randomly. After preparing the teeth and taking the shoulder impression with polyether in dental simulate on the training system, the surface roughness of the shoulder impression in mesial, middle and distal areas was scanned and compared. The data were analyzed using SPSS 25.0 software package.@*RESULTS@#(1) There was no significant difference in Ra and Rz values between the abutment shoulder and impression shoulder in different areas. (2) The surface roughness of the shoulder impression prepared by ultrasonic instruments [Ra:(6.59±2.33) μm, Rz:(34.69±7.29) μm] was significantly smaller than that of the rotary instruments [Ra:(21.79±4.89) μm, Rz:(91.69±14.82) μm] (P < 0.05). The morphology of the shoulder prepared by ultrasonic instruments was clear and continuous under microscope observation. (3) The surface roughness of each area of the shoulder prepared by ultrasonic instruments was significantly lower than that of the rotary instruments (P < 0.001); there was no significant difference of the surface roughness (Ra) in each area of the shoulder impression after ultrasonic instrument preparation, while the shoulder impression roughness in the mesial and distal areas was significantly higher than that in the middle area (P < 0.001) after rotary instrument preparation.@*CONCLUSION@#Compared with the rotary instruments, the ultrasonic instruments can obtain a smoother shoulder surface, especially can significantly improve the shoulder preparation effect near the proximal surface.
Subject(s)
Humans , Bicuspid , Microscopy, Electron, Scanning , Shoulder , Surface Properties , UltrasonicsABSTRACT
Objective:To compare quantitatively the quality of the canal isthmus retropreparation among three kinds of ultrasonic ret-rotips.Methods:1 20 maxillary bicuspid teeth with two canals and an isthmus were randomly assigned to 3 groups(n=40).The canal isthmus retropreparation were made respectively using ultrasonic niti tip RE2,diamond tip Berutti and #25K file.Image processing and analysis system were used to measure the preoperative and postoperative parameters for further evaluation.Results:The cutting volume of ultrasonic niti tip RE2 group was significantly less than those of other two groups(P<0.05).Conclusion:Ultrasonic niti tip RE2 is feasible in the canal isthmus retropreparation.
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Objective:To compare the quality of the canal isthmus retropreparation among three ultrasonic retrotips.Methods:120 maxillary bicuspid teeth with 2 canals and an isthmus were randomly assigned to 3 groups(n =40).The canal isthmus were retro-preparated by ultrasonic Ni-Ti tip RE2,diamond tip Berutti and #25K file respectively.The quality of cavity margin,the number and type of the micro-cracks were evaluated by SEM.Data were statistically analysed by Kruskal Wallis Test of SPSS 13.0.Results:The cavity margin quality of ultrasonic Ni-Ti tip RE2 group was superior to that of other 2 groups(P =0.003);The number of micro-crack in Ni-Ti tip RE2 group was less than that of other 2 groups(P =0.003).The type of micro-cracks has no significant difference among the 3 groups(P =0.830).Conclusion:Ultrasonic Ni-Ti tip RE2 is feasible in the canal isthmus retropreparation.
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Objective:To compare the quality of root-end preparation quantitatively between ultrasonic retrotips and traditional slow-speed handpiece. Methods: 27 maxillary second bicuspid teeth with two canals and an isthmus were randomly assigned to 3 groups.Root-end preparations were made respectively using ultrasonic diamond tip Berutti and niti tip RE2, ultrasonic 40~#K file and slow-speed handpiece with No.2 round bur. Image processing and analysis system were used to measure the preoperation and postoperation parameters for further evaluating the difference between the two techniques. Results: The cutting volume of ultrasonic instruments was less than slow-speed handpiece(P<0.000 1). Conclusion: Ultrasonic instrument is better in the root-end preparation than traditional slow-speed handpiece.
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Objective:To compare the quality of root-end preparation quantitatively between ultrasonic retrotips and traditional slow-speed handpiece.Methods:27 maxillary second bicuspid teeth with two canals and an isthmus were randomly assigned to 3 groups.Root-end preparations were made respectively using ultrasonic diamond tip Berutti and niti tip RE2,ultrasonic #40K file and slow-speed handpiece with No.2 round bur.Image processing and analysis system were used to measure the preoperation and postoperation parameters for further evaluating the difference between the two techniques.Results:The cutting volume of ultrasonic instruments was less than slow-speed handpiece(P
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Objective:To evaluate the effect of retrograde preparation by using slow-speed handpiece or by ultrasonic tips.Methods:Forty-eight extracted premolars were inspected with Scanning Electron Microscope for the minimum dentine thickness recorded after preparation of root-end cavities by low-speed handpiece and ultrasonic instrument respectively.Results:By using slow-speed handpiece,the minimum dentine thickness recorded after the preparation of root-end cavities was 0.15 mm;whereas that was 0.82 mm and 0.76 mm by ultrasonic instrument with S12 9D and S12 9 respectively(handpiece vs ultrosonic instrument,P
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This paper introduces the theory and structure of FPGA.The excellent performance and powerful developing system of FPGA greatly reduce the designing and developing cost,and promote modern medical instruments in the aspects of micromation,multi-function and seriation.Emphasis is put on the application of FPGA to ECG,ultrasonic instruments and endoscope.