OBJECTIVE: To evaluate the benefits of surgical repair acute type A aortic dissection (ATAAD) on survival of octogenarians. METHODS: Patients who underwent surgery for acute ATAAD from the multicenter European Registry of Type A Aortic Dissection (ERTAAD) were the subjects of the present analysis. RESULTS: 326 (8.4%) patients were aged ≥ 80 years. Among 280 propensity score matched pairs, in-hospital mortality was 30.0% in patients aged ≥ 80 years and 20.0% in younger patients (P = 0.006), while 10-year mortality were 93.2% and 48.0%, respectively (P < 0.001). The hazard of mortality was higher among octogenarians up to two years after surgery, but it became comparable to that of younger patients up to 5 years. Among patients who survived 3 months after surgery, 10-year relative survival was 0.77 in patients aged < 80 years, and 0.46 in patients aged ≥ 80 years. Relative survival of octogenarians decreased markedly 5 years after surgery. Age ≥ 85 years, glomerular filtration rate, preoperative invasive ventilation, preoperative mesenteric mal-perfusion and aortic root replacement were independent predictors of in-hospital mortality among octogenarians (AUC = 0.792; E:O ratio = 0.991; CITL = 0.016; slope = 1.096). An additive score was developed. A risk score ≤ 1 was observed in 68.4% of patients, and their in-hospital mortality was 20.9%. CONCLUSIONS Provided a thoughtful patient selection, surgery may provide a survival benefit in patients aged ≥ 80 years with ATAAD that, when compared to younger patients and the general population, may last up to 5 years after the procedure. These findings have significant epidemiologic and clinical relevance because of the increasing longevity of the population of the Western countries.

PURPOSE: While dental implants have displayed high success rates, poor mechanical fixation is a common complication, and their biomechanical response to occlusal loading remains poorly understood. This study aimed to develop and validate a computational model of a natural first premolar and a dental implant with matching crown morphology, and quantify their mechanical response to loading at the occlusal surface. MATERIALS AND METHODS: A finite-element model of the stomatognathic system comprising the mandible, first premolar and periodontal ligament (PDL) was developed based on a natural human tooth, and a model of a dental implant of identical occlusal geometry was also created. Occlusal loading was simulated using point forces applied at seven landmarks on each crown. Model predictions were validated using strain gauge measurements acquired during loading of matched physical models of the tooth and implant assemblies. RESULTS: For the natural tooth, the maximum vonMises stress (6.4 MPa) and maximal principal strains at the mandible (1.8 mε, −1.7 mε) were lower than those observed at the prosthetic tooth (12.5 MPa, 3.2 mε, and −4.4 mε, respectively). As occlusal load was applied more bucally relative to the tooth central axis, stress and strain magnitudes increased. CONCLUSION: Occlusal loading of the natural tooth results in lower stress-strain magnitudes in the underlying alveolar bone than those associated with a dental implant of matched occlusal anatomy. The PDL may function to mitigate axial and bending stress intensities resulting from off-centered occlusal loads. The findings may be useful in dental implant design, restoration material selection, and surgical planning.
Bicuspid ; Crowns ; Dental Implants ; Dental Occlusion ; Finite Element Analysis ; Humans ; Mandible ; Periodontal Ligament ; Stomatognathic System ; Tooth