Determination of energy-dependent neutron backgrounds using shadow bars

Understanding the neutron background is essential for determining the neutron yield from nuclear reactions. In the analysis presented here, the shadow bars are placed in front of neutron detectors to determine the energy dependent neutron background fractions. The measurement of neutron spectra with and without shadow bars is important to determine the neutron background more accurately. The neutron background, along with its sources and systematic uncertainties, are explored with a focus on the impact of background models and their dependence on neutron energy.Comment: 7 pages, 10 figure

Pre-surgical fixed prosrhesis planning and building for immediate implant loading.

Objective: The aim of the present study was to test the value of a new technique based on the concept of the prosthodontic-driven implant placement for the immediate loading of implants in the treatment of full and partial edentulism. Background: New CAD-CAM sistems have given clinicians the possibility to use data from computerized tomography to plan implant rehabilitation and to transfer this information to the surgical phase. The introduction of scannografic templetes and the fabrication of a pre-surgical provisional prosthesis made reliable the concept of the prosthodontic-driven implant placement. Materials and Methods: 8 patients were included: 5 were completely edentulous, 2 had full edentulous maxilla, but partial edentulous mandible, 1 was fully edentulous in the mandible. A total of 94 implants were placed. Flapless surgery was used. In 4 patient both drilling and implant placement was templete-guided, while, in the other 4, implant placement was non-guided. The provisional prosthesis was delivered as soon as the surgery finished. Final metal-ceramic restoration was delivered in 2 weeks. All patients underwent to control CT. Implant positions in the virtual planning was compared to the actual implant position obteined as visualized in the control CT. Results: Two implats were lost in the 8 patients during the first year. Success rate in repeating virtual planned implant position was 96,55% on the vestibular-oral/lingual axis; 86,21% on the mesio-distal axis and 91,38% on the whole. When implant placement was non-guided, success rates have been lower. All patients were very satisfied of the treatment received. Conclusions: This study indicates that the technique proposed could be a reliable treatment option and that the CAD-CAM sistem used is resonably precis

Accuracy of 2 Different Cad-Cam Devices for Implant Placement.

Objective: CAD-CAM technology allows clinicians to plan implant position on CT images and to fabricate customized surgical templates for transferring this information to the surgical field. The aim of the present study was to investigate the accuracy of a new device (SAFE SurgiGuide) of a CAD-CAM system for implant placement (Simplant®-Materialise, Leuven, Belgium) compared with the traditional one (SurgiGuide). Methods: Ten patients were included and were treated with the Simplant® system. All patients received a scannographic template and underwent CT-Dentascan. CT images were used for planning implant positioning with the SimplantPro® software. Patients were divided into two groups: “SAFE SurgiGuide Group” (SSG), and “SurgiGuide Group” (SGG). Those in the SSG received implants with the SAFE SurgiGuide device, which uses special drills with stopping depth collars, one template with changeable drilling cylinders, and implant holders for fixture placement. In the SGG, 3 different templates (SurgiGuide) were used in each patient to guide drilling. Eighty-eight implants were placed. Two months after surgery, a control CT-scan was taken, and images of planned and placed implants were compared. Results: Success rates for repetition of virtual and planned implant positions were: on the vestibular-oral/lingual axis, SSG = 98.35% vs. SGG = 47.39%; on the mesio-distal axis, SSG = 89.4% vs. SGG = 65.73%; and whole SSG = 96.62% vs. SGG = 56.97%. The distance from anatomical reference structures was always respected. Conclusions: The Simplant® System allows clinicians to make precise pre-surgical evaluations and treatment programs, and to transfer them securely to the surgical phase. Better results seemed to be obtained with the Safe SurgiGuide

Flapless surgery and immediate loading of implants in fully edentulous patients using computer-aided implant surgery.

Aim of the work. The aim of this report is to elucidate how is possible to obtain , in complete edentulism treatment, a truly immediate loading using dedicated SimPlant software , that offer all information for the guided implant placement and the creation of a temporary prosthesis beforehand. Materials and methods. A CT scan was taken with a complete radiopaque scan prosthesis; the CT data were prepared for using by the SimPlant Pro 8.3 software to plan the exact position of the implants. Following these guidelines a mucosa-supported SurgiGuide is produced. A flapless implant site preparation was performed . In total 22 implants were placed in complete edentulous patient. The abutments were positioned and the impression for the final restoration was taken. Immediately the patient received the temporary bridge that was prepared prior to the surgery in the dental laboratory. Results and conclusions. Due to the flapless surgery, postoperative swelling and pain are limited. The computer-aided planning and SurgiGuide templates allow us to place a temporary fixed prosthesis within hours and an aesthetic and functional final restoration within some days

Implants Healing Sequence in Grafted Bone: Clinical Evaluation.

Objective: To understand the sequence of bone graft healing, the role of graft on implant-bone integration and the influence of early loading on both tissues. Methods: 58 implants were placed in atrophic alveolar ridges; residual bone defects were corrected with particle bone graft stabilized by titanium mesh. After 2 months a second surgical access was made to evaluate bone graft incorporation and implant stability by using Resonance Frequency Analysis. Implants were loaded as soon as their stability reached 57ISQ. Results: 3 of 58 implants were lost during 1,5 year follow-up. In 68,3% of the sample a complete filling of alveolar ridge defect was observed. Average primary stability was 53,46ISQ. Average stability values (ASV) increment was higher during the first 2 months (ASV 61,25ISQ) and raised until the fourth month (ASV 65,35ISQ), during the first prosthetic-loading period. 84.63% of the fixtures reached the 57ISQ threshold value after 2 months. When the graft was not full incorporated, implant stability increased more slowly and was more influenced by prosthesization. Conclusions: 2 months seems to be enough time to guarantee bone graft incorporation; bone graft seems to increase implant stability especially in the first healing period, allowing early loading. Early prosthethic-loading does not appear to jeopardize bone grafts healing, but to slightly augment ISQ values

Computer-aided implant therapy [Terapia implantare computer-assistita]

CAD-CAM technology allows to plan implant position on CT images and to produce customized surgical template to transfer this information to surgical sites. The aim of this study was to check utility and accuracy of a new CAD-CAM system in the treatment of full and partial edentulism. 10 patients were enrolled in the sample and treated with the system. All patients received a template and underwent CT-DentaScan. CT images were used for planning implant position with the software. Patients were divided into two groups: the "Guided Group", where implant placement as well as drilling was template guided; and the "Non-Guided Group", where only drilling was template-guided. Overall 92 implants were placed. Two months after surgery a control CT-scan was taken and images of both planned and placed implants were compared. Success rate in repeating virtually planned implant position was 96.55% on the vestibular-oral/lingual axis; 86.21% on the mesio-distal axis and 91.38% on the whole. When implant placement was not template guided, success rates were lower. Distances from anatomical landmarks were always respected. The software allows to make accurate pre-surgical evaluation and treatment programs and to transfer them safely to surgical sites. This system appear to be a valid help in the treatment of difficult implant-supported rehabilitations

Cone-Abutment Connection and Zirconia Restorations Influence on Peri-Implant Tissues Health.

Objective: Stable crestal bone levels are believed to be critical for the long-term implant success. After implant insertion and loading, crestal bone usually remodels to a level about 2.0mm apical to the the implant–abutment junction in two-piece implants. This could be lead to a localized inflammation of the peri-implant tissues. The aim of this study was to evaluate the clinical outcomes of cone connection implants and zirconia restorations on peri-implant tissues. Methods: 91 Morse cone connection implants (Ankylos® Dentsply Friadent, Mannheim, Germany) were inserted in 53 patients, ranging in age between 27 and 65 years old, to correct partial or single edentulisms. After an healing period of 2 months, the implants were loaded, for 1 month with resin provisional prosthesis and then with Zirconia core fixed partial dentures and were monitorized every 3 months for 2 years. The crestal bone height was evaluated with digital standardized radiographs; mSBI, mPlI, suppuration or gingival enlargment were recorded to study soft tissue conditions. Results: Mean crestal bone loss at interproximal surfaces was ≤0,5 mm. Stable bone above the implant shoulder was detected in case of subcrestal positioning of the implant. No infrabony pockets were present. mPlI≤1 and mSBI≤1 were recorded regardless of patient smoking or hygene habits; no suppurations or gingival enlargments were observed. Conclusions: It has been claimed that morse tapered abutment connection provides high resistance to micromotion and bacteria infiltration and that Zirconia provocs lower inflammatory level in surrounding tissues than titanium. Clinical outcomes seem to confirm reduced inflammatory manifestation of peri-implant soft and mineralized tissues using this kind of implant-prosthesis

Differential expression of lectin binding sites in equine compact and expanded cumuli oocytes

(Cp) or expanded (Ex) cumuli. Cp-oocytes nave lower meiotic competence, slower rate of maturation, reduced ability to respond to activation stimuli and reduced male pronucleus formation rate after ICSI when compared to Ex-oocytes. Glycoconjugates play a key role in oocyte maturation and fertilization. We here investigated the glycoconjugate expression in equine Cp and Ex cumuli by lectin histochemistry. Cumulus-enclosed oocytes from abbattoir ovaries were fixed in Bouin's solution and embedded in paraffin wax after in vitro maturation. Sections (5 um thick) were stained with il lectins (SNA, PNA, DBA, RCA120, SBA, HPA, Con A, GSA I-B4, GSA II, UEA I, LTA). The ooplasm of Cp-oocytes showed a major reactivity for SNA, SBA, HPA, GSA I-B4 with respectto Ex ones,whereas botri type of oocytes displayed same affinity for DBA, Con A, GSA II and no binding sites for PNA, DBA, RCA120, UEA I, LTA. The zona pellucida of botri Cp and Ex oocytes were unreactive for GSA I-B4, GSA II, UEA I, ITA whereas in Cp oocytes showed no binding sites for SNA and PNA, a lower staining with RCA120 and a higher reactivity for HPA than Ex ones. Corona radiata cells from both oocytes types did not react with DBA, showed same reactivity with SNA, RCA120, GSA I-B4, and GSA II. In Cp-oocytes, it did not react with PNA but showed major affinity for SBA, HPA, Con A, UEA I, and LTA. The different glycoprotein pattern observed between equine Cp and Ex oocytes may be related to their different meiotic and developmental competence. Research supportated by MIUR COFIN-PRIN 200