A Study on the Development and Application of Patellofemoral Joint Radiography Auxiliary Device for Tangential Axial Radiography of the Patellar and Patellofemoral Joints

This study evaluated the accuracy of tangential axial radiography of the patellofemoral joints using an auxiliary device, which we named patellofemoral joint radiography (PJR). To compare the PJR and conventional radiography methods such as the Laurin, Merchant, and Settegast, the images taken by three methods were evaluated using a whole body phantom (PBU-31). Settegast was the radiographic method that had the smallest inclination of the patella and showed the best half lateral image of the patella, with a difference of 5.76% when compared with PJR (p = 0.001). PJR was the method that had the largest distance between the patellar and femoral joint spaces, with a difference of 14.54% when compared with the Merchant method (p = 0.001). PJR was the method in which the two bones were well overlapped (i.e., measured by the distance between the femoral trochlear groove and the tibial tuberosity), with a difference of 109.41% when compared with the Merchant method (p = 0.001). The Settegast method has the image with the smallest inclination of the patella, but the PJR has the image that best describes the patellofemoral joint and the least distortion of the image. when using PJR, bending the knee by 40° degree and setting a 140° angle between the long axis of the femur and the long axis of the lower leg were considered to be the most beneficial conditions. We propose the use of PJR for tangential axial radiography of the patellar and patellofemoral joints.

Behavior of implant and abutment sets of three different connections during the non-axial load application: An in vitro experimental study using a radiographic method

BACKGROUND: During the masticatory cycle, loads of different intensities and directions are received by the dental structures and/or implants, which can cause micromovements at the junction between the abutment and implant. OBJECTIVE: The objective of this in vitro study was to evaluate the behavior of three different implant connections subjected to different load values using a digital radiography system. Additionally, the torque values for removing the abutment screws were also measured and compared. METHODS: Ninety sets of implant and abutment (IA) were used, divided into three groups according to the type of connection (n = 30 per group): EH group, external hexagon type connection; IH group, internal hexagon connection; and, MT group, Morse taper connection. RESULTS: MT group showed the better vertical misfit behavior at the three intensity of load applied, in comparison with EH and IH groups. In the analysis of torque maintenance (detorque test), MT group showed higher values of detorque when compared with the measured values of EH and IH groups (p < 0.001). CONCLUSIONS: The IA sets of EH and IH groups showed a microgap in all levels of applied loads, unlike the MT group this event was not observed. In the detorque test, MT group increase in the torque values when compared to the initial torque applied, unlike EH and IH groups showed a decrease in the initially torque applied in all conditions tested. A positive correlation was detected between the misfit and detorque values.

Accuracy of digital bitewing radiographs with and without applying horizontal tube shift in the diagnosis of residual excess cement around dental implants: An in vitro study.

Purpose: This study was designed to evaluate the diagnostic value of digital Bitewing (BW) radiographs with and without horizontal tube shift in detecting Residual excess cement (REC) on the proximal and non-proximal surfaces of implant restorations. Material and Methods: Eight mandibular models were fabricated with two implants placed on each side in the premolar and first molar positions. Excess cement was applied to either proximal or non-proximal surfaces of the restorations intentionally during the process of crown cementation. BW radiographs with and without applying horizontal tube shift were acquired. Three maxillofacial radiologists were asked to determine the presence and location of REC in the radiographs. Sensitivity and specificity of the radiographic technique were assessed according to the restoration surface that contained REC. Results: Sensitivity of BW radiographs was 100% for the detection of REC on the proximal surfaces and 41-18, 80% on the non-proximal surfaces. Specificity of the technique was 85.71%-100% for the proximal surfaces and 75-94. 12% for the non-proximal areas. Specificity of the radiographic method was generally greater than its sensitivity for the non-proximal surfaces while in the proximal areas, the two variables had quite similar values. Conclusion: Digital BW radiography is generally more useful for detection of REC on the proximal surfaces. Higher specificity of this technique for the bucco-lingual surfaces suggests more reliability of the negative diagnoses in the non-proximal areas.

Comparative assessment of a new electronic apex locator and radiographic measurement of root length in primary teeth: An in-vitro study.

Background: The success of pulpectomy relies upon exact measurement of root length. Traditionally, radiographs were the main tools for measuring root length; however, they have several limitations. Hence, Electronic apex locators have become popular these days. Aim and objective: To assess the efficiency of Propex Pixi and traditional radiographic method in measuring the root length of single rooted primary teeth. Materials and Methods: Thirty extracted human single rooted primary teeth were selected randomly. In-vivo environment was simulated by inserting tooth sample in alginate and the root length was determined by using Propex Pixi. Secondly, the root length was determined by conventional radiographic method and finally the exact root length was measured by direct visual method. Statistical analysis: The obtained data was assessed using Student paired ‘t’ test, intra-class correlation coefficient and regression analysis. Results: The study showed no significant difference between Propex Pixi and radiographic method(p=0.280). Both the electronic and radiographic methods displayed a high equivalence and compliance R=0.947 and R=0.826 with the actual measurement. Conclusions: Propex Pixi was as effective as radiographic method in measuring the root length of primary teeth. However, regression analysis showed that Propex Pixi can anticipate the exact value with 94.3% accuracy and radiographic method with 67.2% accuracy.