Pull-off resistance of a screwless implantabutment connection and surface evaluation after cyclic loading

Purpose@#The aim of this study was to investigate to what extent cyclic load affects the screwless implant-abutment connection for Morse taper dental implants. @*Materials and Methods@#16 implants (SICvantage max) and 16 abutments (Swiss Cross) were used. The screwless implant-abutment connection was subjected to 10,000 cycles of axial loading with a maximum force of 120 N. For the pull-off testing, before and after the same cyclic loading, the required force for disconnecting the remaining 6 implant-abutment connections was measured. The surface of 10 abutments was examined using a scanning electron microscope 120× before and after loading. @*Results@#The pull-off test showed a significant decrease in the vertical force required to pull the abutment from the implant with mean 229.39 N ± 18.23 before loading, and 204.30 N ± 13.51 after loading (P <.01). Apart from the appearance of polished surface areas and slight signs of wear, no visible damages were found on the abutments. @*Conclusion@#The deformation on the polished abutment surface might represent the result of micro movements within the implant-abutment connection during loading. Although there was a decrease of the pull-off force values after cyclic loading, this might not have a notable effect on the clinical performance.

Pull-off resistance of a screwless implantabutment connection and surface evaluation after cyclic loading

Purpose@#The aim of this study was to investigate to what extent cyclic load affects the screwless implant-abutment connection for Morse taper dental implants. @*Materials and Methods@#16 implants (SICvantage max) and 16 abutments (Swiss Cross) were used. The screwless implant-abutment connection was subjected to 10,000 cycles of axial loading with a maximum force of 120 N. For the pull-off testing, before and after the same cyclic loading, the required force for disconnecting the remaining 6 implant-abutment connections was measured. The surface of 10 abutments was examined using a scanning electron microscope 120× before and after loading. @*Results@#The pull-off test showed a significant decrease in the vertical force required to pull the abutment from the implant with mean 229.39 N ± 18.23 before loading, and 204.30 N ± 13.51 after loading (P <.01). Apart from the appearance of polished surface areas and slight signs of wear, no visible damages were found on the abutments. @*Conclusion@#The deformation on the polished abutment surface might represent the result of micro movements within the implant-abutment connection during loading. Although there was a decrease of the pull-off force values after cyclic loading, this might not have a notable effect on the clinical performance.

Factors affecting difference between EGW and AGW in liver transplantation

Background: An accurate preoperative estimate of the graft weight and remnant liver volume is vital to avoid small-for-size syndrome[SFSS] in the recipient and ensure donor safety after Living donor liver transplantation [LDLT]. CT has been widely used as a method for the preoperative volumetric assessment of the liver transplantation. The graft size as measured from preoperative imaging which is often different from the actual weight of the liver graft as obtained by the donor hepatectomy. The difference between preoperative volumetry and Actual graft weight [AGW] was graded into minimal difference [15%]

Aim of the Work: This study was conducted to assess different preoperative factors that might affect the difference between estimated graft weight and actual graft weight in liver transplantation

Patients and Methods: This single center retrospective study was conducted on 86 cases who have been subjected to donation for liver transplantation in Ain Shams Center of organ transplantation. Donors were divided into two groups: Group [A]: formed of 33 donors who showed minimal difference [15%] between EGV and AGW. Each donor data was examined for: Age, Sex: male or female, Body mass index [BMI], Lipid profile [positive / negative] Type of hepatectomy [Rt lobe / Lt lobe], AGW.Estimated graft weight [EGW], Total liver volume, Liver biopsy: Fibrosis [positive/ negative], Steatosis: Negative: [0%] and Positive: [5% or 10%]

Results: EGW of 903 gm was identified as cutoff point of the best specificity with the best sensitivity showing 60.4% and 60.6% for sensitivity and specificity, respectively. At this cutoff point, 47.7% of cases [n=41] showed EGW < 903 gm, while 52.3% of cases [n=45] showed EGW >/= 903 gm. Thus, it can be said that cases showed EGW >/= 903 gm have a probability of 71.1% to have big difference between EGW and AGW [>/=15%]. EGW of 1069 gm was identified as another cutoff point of a better specificity on ROC curve showing 32.1% and 93.9% for sensitivity and specificity, respectively, on ROC curve. At this cutoff point, 77.9% of cases [n=67] showed EGW < 1069 gm, while 22.1% of cases [n=19] showed EGW >/= 1069 gm. Thus, it can be said that cases showed EGW >/=1069 gm have a probability of 89.5% to have big difference between EGW and AGW [>/=15%]. TLW of 1587 gm was identified as cutoff point of the best specificity with the best sensitivity and specificity on ROC curve showing 56.6% and 60.6% for sensitivity and specificity, respectively, on ROC curve. At this cutoff point, 50% of cases [n=43] showed TLW < 1587 gm, while 50% of cases [n=43] showed TLW >/= 1587 gm. Thus, it can be said that cases showed TLW >/=1587 gm have a probability of 69.8% to have big difference between EGW and AGW [>/=15%]. TLW of 1807 gm was identified as another cutoff point of better specificity on ROC curve showing 18.9% and 93.9% for sensitivity and specificity, respectively, on ROC curve. At this cutoff point, 86% of cases [n=74] showed TLW < 1807 gm, while 14% of cases [n=12] showed TLW >/= 1807 gm. Thus, it can be said that cases showed TLW >/=1807 gm have a probability of 83.3% to have big difference between EGW and AGW [>/=15%]

Conclusion: TLV and EGV in CT volumetry are most reliable preoperative factors that can predict big difference between EGW and AGW. Re-evaluation of CT volumetry protocol is recommended for better prediction

Closed reduction and percutaneous pinning of fracture surgical neck of the humerus

In dealing with displaced proximal humeres fractures, there is still much controversy in treatment modalities. The aim of this work was to evaluate the out come of closed reduction and percutaneous pinning as a line of treatment. The technique of closed reduction and percutaneous fixation was carried out for 20 cases with displaced two part fracture of the surgical neck of the humerus. The study included 15 males and 5 females. The average age was 43.7 years with an average follow up period of 10.65 months and the average healing time was 9.2 weeks. All patients were available for follow up and all fractures achieved union. The functional outcome was evaluated using the University of California at Los Angeles Shoulder Scale [UCLA] scoring system. According to this scoring system, the results were: 9 excellent cases [45%], 8 good cases [40%] and 3 fair cases [15%]. With proper patient reelection, closed reduction and percutanoues pinning is a good modalities for treatment of displaced two part fracture of the surgical neck of humerus

Operative treatment of displaced intra-articular fracture calcaneus

Since July 2000, fifteen cases with displaced intra-articular fractures of the calcaneus had been treated by open reduction and internal fixation using AO calcaneal plate arid screws. The objective was to evaluate the outcome of surgical fixation of the displaced intra-articular fractures of calcaneus. Using Sanders C.T. classification system, four cases were grouped as type II; nine as type III; and two as type IV. All the patients were reviewed at a minimum of 1 year. The functional results were evaluated using the Maryland foot score. The functional results were considered excellent in 5 cases [33.3%]; good in 6 [40%]; fair in 3 [20%]; and poor in one case [6.7%]. Postoperatively, the height and length of the calcaneal body returned in 100% of cases of group II; 78% of group III; and 50% of group IV. Complications included three cases with postoperative superficial infection; one, wound edge necrosis; one, had subtalar arthritis; and two, had a reflex sympathetic dystrophy. We concluded that operative fixation of displaced intra-articular fractures of the calcaneus by AO plate, restores the calcaneal height, allows early mobilization and weight-bearing, and maximizes the chances for good joint function

Total knee arthroplasty with unresurfaced patella

In this prospective study, we evaluated the outcome of total knee replacement without resurfacing of the patella in 97 cases. There were 55 males and 42 females. The age at the time of surgery ranged from 65 to 81 years. All patients underwent cementless total knee replacement [Profix, Smith and Nephew]. The patients were assessed, at intervals of 6 weeks, 6 months and 18 months postoperatively. The mean follow up of the last visit was 15.3 months. We used the knee society score and the patellar score for assessment. According to the final, knee society score results, the outcome was excellent in 35 cases [36.1%], good in 42 cases [43.3%], fair in 12 cases [12.4%] and poor in 8 cases [8.2%]. The patellar score was satisfactory [excellent and good] in 83 cases [85.6%] and poor in 13 cases [14.4%]. The results of total knee replacement with the implant design used in this study and routine patellar retention provided satisfactory mid-term outcome and a high degree of patient satisfaction