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Objective: To study the effect of the modified preparation method with root canal flushing of different solutions on the anti-fracture properties of mechanical nickel-titanium filings. Methods: A transparent resin model of root canal was established. ProTaper Universal (PTU F1) instrument was used to prepare the root canals. The number of prepared root canals by each PTU F1 with the various solutions(n = 20) was recorded and compared among groups. Results: 6. 13 ± 3. 52 root canals were prepared in distilled water group, 6. 25 ± 1. 76 in 0. 9％saline group, 6. 27 ± 2. 07 of 0. 2％ chlorhexidine group, 6. 88 ± 3. 21 in 1％ sodium hypochlorite group, 4. 31 ± 2. 34 in 5％ sodium hypochlorite group and 3. 26 ± 2. 08 in dry drilling group. The number between each 2 of distilled water, 0. 9％saline group, 0. 2％chlorhexidine group and 1％ sodium hypochlorite group, and the number between 5％ sodium hypochlorite group and dry drilling group was not statistically significant(P＞ 0. 05). The number of prepared root canals in the first 4 groups was more than that in the latter 2 groups(P＜ 0. 05). Conclusion: Distilled water, 0. 9％ saline, 0. 2％ chlorhexidine or 1％ sodium hypochlorite for root canal irrigation can improve mechanical nickel-titanium instrument for fatigue resistance in root canal preparation, but 5％ sodium hypochlorite and dry drilling can not.
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<p><b>OBJECTIVE</b>To compare the stripping length obtained through the model of 0.012 and 0.014 of the nickel-titanium dual-stage maxillary sinus mucosa stripper, and the umbrella detacher.</p><p><b>METHODS</b>Twenty-four goats (1.5-2 years old) were chosen, randomly divided into A, B, C groups, each group of eight. Group A was 0.012 model group, group B was 0.014 model group, group C was umbrella detacher group. Animal model was established, and maxillary sinus mucosa was stripped to the left and right sides of the bottom of the sinus in three groups. The data was measured when stripping to the limit or being perforated.</p><p><b>RESULTS</b>The average length of group A was 12.41 mm±4.35 mm, two cases perforated. The average length of group B was 23.38 mm±4.84 mm, one case perforated. The average length of group C was 2.61 mm±0.30 mm. The population mean of stripping length in three groups was not all the same calculated by analysis of variance (P<0.01). There were significant differences in the stripping length of the three groups by the SNK test (P<0.05).</p><p><b>CONCLUSIONS</b>The nickel-titanium dual-stage maxillary sinus mucosa stripper can achieve a larger mucosal stripping range. The stripper with a model of 0.014 has a moderate flexibility and safety, and it can strip a large area of sinus mucosa. .</p>
Subject(s)
Animals , Goats , Maxillary Sinus , Models, Animal , Mucous Membrane , Nickel , Sheep , TitaniumABSTRACT
<p><b>OBJECTIVE</b>This study aimed to explore the differences of membrane thickness and pressure on the paranasal sinus membrane in goats and analyze their causes. The results can provide theoretical basis and guidance for the issues of the maxillary sinus floor augmentation related to the membrane.</p><p><b>METHODS</b>The membrane was cut into two sizes from every sinus membrane. The membrane was fixed in formalin to obtain tissue specimens for the membrane thickness study and pressure study. The correlation between the two parameters was then analyzed, and appropriate statistical methods and software were selected.</p><p><b>RESULTS</b>The top of maxillary sinus, the bottom of maxillary sinus and the frontal sinus membrane thickness were (410.03 ± 65.97), (461.33 ± 91.37), (216.90 ± 46.47) µm. The pressure were (260.08 ± 80.12), (306.90 ± 94.37), (121.72 ± 31.72) kPa. The mean differences of the membrane thickness between the top of the maxillary sinus and the frontal sinus, bottom and frontal, and top and bottom were statistically significant (P < 0.05). The mean differences in membrane pressure were also statistically significant (P < 0.05).</p><p><b>CONCLUSION</b>The membrane thickness and pressure of the top and bottom of the maxillary sinus are higher than those of the frontal sinus membrane. However, the thickness and pressure of the bottom membrane are slightly higher than those of the top membrane. Pressure and membrane thickness are positively correlated in the sinus membrane.</p>
Subject(s)
Animals , Goats , Maxillary Sinus , Sinus Floor Augmentation , SoftwareABSTRACT
Objective To evaluate the diagnostic value of MR arthrography for rotator cuff tear. Methods A prospective study was undertaken in 32 patients with shoulder diseases using MR arthrography. Abnormalities revealed on MR arthrography of the rotator cuff, the labrum, and the tendon of the long head of the biceps brachii muscle were recorded. The results of MR arthrography were compared with those of arthroscopy and surgery. Results Based on the results of arthroscopy and surgery, 32 patients comprised 14 complete rotator cuff tear, 6 partial rotator cuff tear, and 12 subjects without tear. For detecting rotator cuff tear, the sensitivity, specificity, and accuracy of MR arthrography were 100%, 100%, 100% respectively. For detecting complete rotator cuff tear, the sensitivity, specificity, and accuracy of MR arthrography were 100%, 94%, 97% respectively. Meanwhile, MR arthrography revealed all multi tendon tear and all abnormalities of the labrum and the tendon of the long head of the biceps brachii muscle before arthroscopy. Conclusion MR arthrography is an accurate and comprehensive method for evaluating rotator cuff tear.
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Objective To determine the val ue of five MR imaging signs in diagnosing the bucket handle tears (BHT) of menisci of the knee. Methods MR imaging of 139 knees with subsequent arthroscope exams were retrospectively evaluated. Based on the results of arthroscopy, 19 knees had BHT of menisci. Two radiologists evaluated each MR exam independently, with discrepancies resolved by consensus. Each MR exam was analyzed for five signs: a double posterior cruciate ligament sign, a flipped meniscus sign, an absent bow tie sign, an internal displaced fragment sign, and an abnormal circumferential meniscus sign. Sensitivity, specificity, positive and negative predictive values, and accuracy for diagnosing BHT of menisci were calculated for the presence of each individual sign. Results The sensitivities of these five signs ranged between 52.6% and 89.5%, and specificities ranged between 83.3% and 98.3%, respectively. Positive and negative predictive values ranged between 42.9% and 88.2%, and between 92 7% and 98.3%, respectively. The accuracy of these five signs ranged between 82.7% and 96 4%. Conclusion BHT of menisci may have many signs on MR imaging. The diagnostic sensitivities of the internal displaced fragment sign and the abnormal circumferential meniscus sign are the highest. The double posterior cruciate ligament sign has the highest specificity and positive predictive value, while the internal displaced fragment sign has the highest negative predictive value and accuracy.
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Objective To compare the diagnostic value of conventional MRI, X ray arthrography, and MRI arthrography in revealing rotator cuff injuries. Methods Thirty two patients with suspected rotator cuff tears were prospectively examined by conventional MRI, X ray arthrography, and MRI arthrography before the examination of shoulder arthroscope. Based on the results of the arthroscopy, the diagnostic sensitivity, specificity and accuracy of those three different methods were determined for rotator cuff tears. Results The arthroscopic findings included 14 full thickness tears, 6 partial thickness tears, and 12 without tears. For the diagnosis of rotator cuff tears,the sensitivity,specificity and accuracy were 80%(16/20), 83%(10/12), and 81%(26/32) for conventional MRI,respectively; the figures were 80%(16/20),100%(12/12), and 86%(28/32)for X ray arthrography,respectively; while the data were 100%(20/20),100%(12/12), 100%(32/32) for MRI arthrography,respectively. For the diagnosis of complete tears, the sensitivity, specificity and accuracy were 79%(11/14), 83%(15/18), and 81%(26/32) for conventional MRI, respectively; the figures were 93%(13/14),94%(17/18), and 94%(30/32) for X ray arthrography, respectively; while the parameters were 100%(14/14),94%(17/18), 97%(31/32) for MRI arthrography, respectively. Conclusion MRI arthrography is one of the best methods for the diagnoses of rotator cuff tears.
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Objective To determine the diagnostic value of indirect MRI arthrography for meniscal tears.Methods 75 cases of routine MRI of the knee and 64 cases of indirect MRI arthrography of the knee were retrospectively reviewed.These patients all had subsequently arthroscopic examination.Based on the results of arthroscopic examination,the diagnostic value for meniscal tear of routine MRI and indirect MRI arthrography were compared.Results For medial meniscal tears,the indirect MRI arthrography gave a sensitivity of 72%,specificity of 100%,accuracy of 89.1%,positive predictive value of 100% and negative predictive value of 84.8%.For lateral meniscal tears,the indirect MRI arthrography gave a sensitivity of 83.8%,specificity of 90.9%,accuracy of 87.5%,positive predictive value of 89.6% and negative predictive value of 85.7%.No matter for medical meniscal tears or lateral meniscal tears,the diagnostic differences between the indirect MRI arthrography and the routine MRI were not statistical significant.Conclusion Although the diagnostic value of indirect MRI arthrography for meniscal tears was quite high,it was not different with routine MRI statistically.