Retention of CAD/CAM All‐Ceramic Crowns on Prefabricated Implant Abutments: An In Vitro Comparative Study of Luting Agents and Abutment Surface Area

Purpose: Previous studies considering retention of cast metal restorations to implant abutments incorporated some degree of frictional fit due to internal surface nodules and roughness of the restoration. In comparison, CAD/CAM restorations have minimal surface irregularities, possibly impacting retention. There is insufficient knowledge of retentive force of CAD/CAM restorations to titanium abutments, and therefore the topic warrants further investigation. This in vitro study investigated the retention of all‐ceramic CAD/CAM restorations to three different prefabricated implant abutments using five different cements. Materials and Methods: A total of 150 Astra Tech dental implant abutments were used, with each group of 50 being subdivided into five groups of 10. An optical impression of each size of abutment was made with the CEREC 3D intraoral camera. A full‐coverage restoration was designed and milled with an enlarged, conical‐shaped occlusal surface, which served to secure the restoration into a brass jig used with a universal testing machine. Five different cements were used with three different‐sized abutments. Following cementation, the implant/abutment/restoration assemblies were stored for 24 hours at 37°C in 100% humidity. A pull‐out test using a universal testing machine, set at a 0.5 mm/min crosshead speed, was used to evaluate retention of the individual restorations. The load required to remove each all‐ceramic restoration was recorded. Retention values were analyzed using ANOVA and Fisher's PLSD multiple comparisons test at the 0.05 level of significance. Results: Peak loads for two provisional cements and a resin‐modified glass ionomer cement ranged from 56 N to 127 N. Peak loads for two resin cements ranged from 184 N to 318 N. Two‐way ANOVA showed significant effects upon retentive forces for both the cement and abutment design. Post hoc Fisher's PLSD multiple comparisons test found significant differences in retention for 7 of the 10 pairings of cements at a 0.05 level of significance. In addition, Fisher's PLSD multiple comparisons test found significant differences between Astra Tech Direct Abutments 4 and Astra Tech Direct Abutments 5 as well as Astra Tech Direct Abutments 4 and Astra Tech Direct Abutments 6 at a 0.05 level of significance. No significant difference was found between Astra Tech Direct Abutments 5 and Astra Tech Direct Abutments 6. Conclusions: Of the five cements tested, the most retrievable CAD/CAM restorations were luted with Temp Bond NE and Improv Temporary Cement. Resin‐modified glass ionomer retentive forces were closer to those of the “temporary cements” than those of the permanent adhesive‐resin cements. The abutment surface area became less important when using adhesive‐resin cements. Retention of CAD/CAM all‐ceramic restorations to prefabricated abutments has not been reported in the literature. This in vitro study demonstrated clinically significant variation among the selected cements used to retain all‐ceramic CAD/CAM restorations to implant abutments. In addition, abutment size influenced the retention of all‐ceramic CAD/CAM restorations.     

First croatian transvaginal laparoscopically assisted cholecystectomies

Background/Aims: The aim of this study was to determine the feasibility and technical aspects of a new endoluminal surgical procedure: transvaginal laparoscopically assisted endoscopic cholecystectomy. Methodology: Three female patients underwent transvaginal laparoscopically assisted endoscopic cholecystectomy (aged 40, 61 and 33 years). Pneumoperitoneum was created through a 5mm supraumbilical incision. Through the posterior fornix of the vagina the second 10mm trocar, laparoscope and 5mm laparoscopic grasper were introduced. The gallbladder was dissected using standard 5mm laparoscopic grasper, hook, electrocoagulation and harmonic shears introduced supraumbilically. The dissected gallbladder was removed in a specimen retrieval bag. Results: Transvaginal laparoscopically assisted endoscopic cholecystectomy was feasible in all patients. No intraoperative or postoperative complications were observed and there was no need for extra-umbilical skin incisions. Total operative time ranged between 60 and 75 minutes. Median length of hospital stay was 1 day. Conclusions: This was the first clinical application of transvaginal laparoscopically assisted cholecystectomy in Croatia. The initial clinical application of this technique in 3 female patients was feasible, effective and safe when performed by experienced laparoscopic surgeons using standard laparoscopic instruments.     

Analysis of the Factors Influencing Functional Outcomes in Patients with Spinal Cord Injury

[Purpose] The extent of functional independence ultimately achieved by an individual patient will be influenced by a variety of medical and non-medical factors. [Subjects and Methods] this study included 419 patients with spinal cord lesions treated in the Clinic for Rehabilitation “Dr M. Zotovic”, Belgrade, Serbia, from January 2000 to December 2009. The patients were divided in two groups according to achievement of increase in Functional Independence Measure (FIM) score of more than 13 at discharge compared to admission. A variety of clinical variables were followed in both groups. [Results] one hundred twenty-one patients (28.9%) showed improvements in FIM score of ≤13, while 298 (71.1%) patients showed an increases in FIM score of >13 at discharge compared to admission. Better functional recovery was observed in patients with non-traumatic spinal cord lesions, lower neurological levels of the lesion (OR = 6.07), and in patients treated surgically, but the level of the spinal cord lesion was the most influential factor affecting outcome. [Conclusion] the patients with spinal cord lesions should not only be grouped by traumatic and non-traumatic lesions only, but also sub-categorized, according to the etiology, level of injury and treatment method.Key words: Spinal cord lesions, Rehabilitation, Functional outcomes