Root surface alterations following manual and mechanical scaling: A comparative study.

OBJECTIVES: The aim of this study was to investigate the morphological and surface roughness changes in dental root samples following periodontal scaling by hand curette, piezoelectric ultrasonic devices or a combination of these. METHODS: Twenty-four monoradicular teeth extracted as a result of periodontal disease were divided into 4 groups: Group A was treated by piezoelectric ultrasonic scaler Piezon® Master 400; Group P by piezoelectric ultrasonic scaler PiezoSmart® ; Group C using Gracey curette 7/8; Group AC by a combined technique of piezoelectric ultrasonic scaler Piezon® Master 400 and Gracey curette 7/8. The treated samples were then analysed using a white light interferometer and scanning electron microscopy (SEM). RESULTS: Roughness analysis revealed major surface alterations in Group C (Sa  = 24.98 µm); the samples treated using the combined technique (Group AC) showed reduced but still significant alteration (Sa  = 14.48 µm), while samples treated with the piezoelectric ultrasonic devices (Group A and Group P) presented the lowest roughness values (Sa  = 8.99 and Sa  = 4.45 µm, respectively). A significant difference was found between groups C and P (P = 0.036). SEM analysis confirmed the roughness analysis revealing non-homogeneous surfaces in Group C, while a less morphological alteration was noted in the other groups. CONCLUSION: All periodontal devices used in this in vitro study produced a certain degree of surface alteration. Hand curettes appear to have a major impact on surface integrity compared with piezoelectric ultrasonic devices.

An array of virtual Frisch-grid CdZnTe detectors and a front-end application-specific integrated circuit for large-area position-sensitive gamma-ray cameras.

We developed a robust and low-cost array of virtual Frisch-grid CdZnTe detectors coupled to a front-end readout application-specific integrated circuit (ASIC) for spectroscopy and imaging of gamma rays. The array operates as a self-reliant detector module. It is comprised of 36 close-packed 6 × 6 × 15 mm(3) detectors grouped into 3 × 3 sub-arrays of 2 × 2 detectors with the common cathodes. The front-end analog ASIC accommodates up to 36 anode and 9 cathode inputs. Several detector modules can be integrated into a single- or multi-layer unit operating as a Compton or a coded-aperture camera. We present the results from testing two fully assembled modules and readout electronics. The further enhancement of the arrays' performance and reduction of their cost are possible by using position-sensitive virtual Frisch-grid detectors, which allow for accurate corrections of the response of material non-uniformities caused by crystal defects.

The Ilizarov fixator in trauma: a 10-year experience.

We reviewed the clinical results of 332 fractures treated with the Ilizarov external fixator between 1984 and 1993. The locations of the involved bones were: tibia, 247 (including 28 with tibial pylons); femur, 47; humerus, 21; forearm, 12 and calcaneus, 5. The clinical outcomes of this series were retrospectively evaluated by radiological and clinical rating systems. In the tibial fractures, results in 71.1% were categorized as excellent or good, without deep infection; 63.3% of the tibial pylon fractures, mostly open, also showed excellent or good results. In the femoral fractures, which were mostly localized at the metaphysis or distal epiphysis, 72% showed excellent or good results, but the patients com-monly complained of knee stiffness. Limitations of range of movement (ROM) in the elbow and the wrist were common in patients with forearm fracture, but ROM was regained after physical therapy. According to the clinical results of the present study, we believed that Ilizarov external fixation was best indicated for tibial fractures, because of its advantage of allowing early weight-bearing. Ilizarov external fixation was also best indicated for: (1) open fractures, (2) comminuted fractures, (3) intra-articular fractures, and (4) fractures with bony defect.