Comparison between analytical and numerical methods for the assessment of masonry arch bridges: Case study of Clemente Bridge on Savio river

This research has focused on the study of the behavior and of the collapse of masonry arch bridges. The latest decades have seen an increasing interest in this structural type, that is still present and in use, despite the passage of time and the variation of the transport means. Several strategies have been developed during the time to simulate the response of this type of structures, although even today there is no generally accepted standard one for assessment of masonry arch bridges. The aim of this thesis is to compare the principal analytical and numerical methods existing in literature on case studies, trying to highlight values and weaknesses. The methods taken in exam are mainly three: i) the Thrust Line Analysis Method; ii) the Mechanism Method; iii) the Finite Element Methods. The Thrust Line Analysis Method and the Mechanism Method are analytical methods and derived from two of the fundamental theorems of the Plastic Analysis, while the Finite Element Method is a numerical method, that uses different strategies of discretization to analyze the structure. Every method is applied to the case study through computer-based representations, that allow a friendly-use application of the principles explained. A particular closed-form approach based on an elasto-plastic material model and developed by some Belgian researchers is also studied. To compare the three methods, two different case study have been analyzed: i) a generic masonry arch bridge with a single span; ii) a real masonry arch bridge, the Clemente Bridge, built on Savio River in Cesena. In the analyses performed, all the models are two-dimensional in order to have results comparable between the different methods taken in exam. The different methods have been compared with each other in terms of collapse load and of hinge positions.

A new yardstick for rating dental arch relationship in patients with complete bilateral cleft lip and palate

Objective: To develop yardsticks for assessment of dental arch relationship in young individuals with repaired complete bilateral cleft lip and palate appropriate to different stages of dental development. Participants: Eleven cleft team orthodontists from five countries worked on the projects for 4 days. A total of 776 sets of standardized plaster models from 411 patients with operated complete bilateral cleft lip and palate were available for the exercise. Statistics: The interexaminer reliability was calculated using weighted kappa statistics. Results: The interrater weighted kappa scores were between .74 and .92, which is in the "good" to "very good" categories. Conclusions: Three bilateral cleft lip and palate yardsticks for different developmental stages of the dentition were made: one for the deciduous dentition (6-year-olds' yardstick), one for early mixed dentition (9-year-olds' yardstick), and one for early permanent dentition (12-year-olds' yardstick).

Dental arch relationship in children with complete unilateral cleft lip and palate following one-stage and three-stage surgical protocols

The objective of this study is to compare dental arch relationship following one-stage and three-stage surgical protocols of unilateral cleft lip and palate. Dental casts of 61 children (mean age, 11.2 years; SD, 1.7), consecutively treated in one center with one-stage closure of the complete cleft at 9.2 months (SD, 2.0), were compared with a sample of 97 patients (mean age, 8.7 years; SD, 0.9), consecutively treated with a three-stage protocol including delayed hard palate closure in another center. The dental casts were assigned random numbers to blind their origin. Four raters graded dental arch relationship and palatal morphology using the EUROCRAN index. The strength of agreement of rating was assessed with kappa statistics. Independent t tests were run to compare the EUROCRAN scores between one-stage and three-stage samples, and Fisher's exact tests were performed to evaluate differences of distribution of the EUROCRAN grades. The intra- and inter-rater agreement was moderate to very good. Dental arch relationship in the one-stage sample was less favorable than in three-stage group (mean scores, 2.58 and 1.97 for one-stage and three-stage samples, respectively; p?arch relationship following one-stage repair was less favorable than the outcome of three-stage repair. The palatal morphology following one-stage repair, however, was more favorable than the outcome of three-stage repair.

A longitudinal three-center study of dental arch relationship in patients with bilateral cleft lip and palate

OBJECTIVE: To compare and evaluate longitudinally the dental arch relationships from 4.5 to 13.5 years of age with the Bauru-BCLP Yardstick in a large sample of patients with bilateral cleft lip and palate (BCLP). DESIGN: Retrospective longitudinal intercenter outcome study. PATIENTS: Dental casts of 204 consecutive patients with complete BCLP were evaluated at 6, 9, and 12 years of age. All models were identified only by random identification numbers. SETTING: Three cleft palate centers with different treatment protocols. MAIN OUTCOME MEASURES: Dental arch relationships were categorized with the Bauru-BCLP yardstick. Increments for each interval (from 6 to 9 years, 6 to 12 years, and 9 to 12 years) were analyzed by logistic and linear regression models. RESULTS: There were no significant differences in outcome measures between the centers at age 12 or at age 9. At age 6, center B showed significantly better results (p=.027), but this difference diminished as the yardstick score for this group increased over time (linear regression analysis), the difference with the reference category (center C, boys) for the intervals 6 to 12 and 9 to 12 years being 10.4% (p=.041) and 12.9% (p=.009), respectively. CONCLUSIONS: Despite different treatment protocols, dental arch relationships in the three centers were comparable in final scores at age 9 and 12 years. Delaying hard palate closure and employing infant orthopedics did not appear to be advantageous in the long run. Premaxillary osteotomy employed in center B appeared to be associated with less favorable development of the dental arch relationship between 9 and 12 years.

Aortic arch morphometry in living humans

Anatomical features of the aortic arch such as its steepness, the take-off angles and the distances between its supra-aortic branches can influence the feasibility and difficulty of interventional and/or surgical maneuvers. These anatomical characteristics were assessed by means of 3D multiplanar reconstruction of thoracic angio-computed tomography scans of 92 living patients (79 males, 13 females, mean age 69.4 ± 9.9 years) carried out for various indications (gross pathology of the thoracic aorta excluded). There was a significant variation of all measured parameters between the subjects - a standard aortic arch (i.e. with all measured parameters within 2 SD) does not seem to exist. There were no significant differences between genders but some of the parameters correlated significantly to age.

Dental Arch Relationships following Palatoplasty for Cleft Lip and Palate Repair

Palatal scarring is assumed to be a primary cause of facial growth derangement in cleft lip and palate. Evidence supporting this hypothesis is confounded by the clinical involvement of various surgeons, and therefore definitive conclusions are not possible. In this study, we investigated the dental arch relationship in two groups, Exposed (47 children; 11.2 yrs) and Unexposed (61 children; 11.2 yrs), with a unilateral cleft lip and palate operated on by the same surgeon. The technique of hard palate repair differed between the two groups. In the Exposed group, palatal bone of the non-cleft side only was left denuded, inducing scar formation. In the Unexposed group, a vomerplasty with tight closure of the soft tissues was applied. Three raters graded the dental arch relationship and palatal morphology using the EUROCRAN Index. The dental arch relationship in the Exposed group was less favorable than in the Unexposed group (p = 0.009). Palatal morphology in both groups was comparable (p = 0.323). This study demonstrates that reduction of denuded bony areas on the palate after palatal repair with a vomer flap had a favorable effect on the dental arch relationship. For palatal morphology, no effect of the type of palatal repair was found.

Early alveolar bone grafting has a negative effect on maxillary dental arch dimensions of pre-school children with complete unilateral cleft lip and palate

To evaluate maxillary dental arch dimensions in pre-school children with a complete unilateral cleft lip and palate (CUCLP) after early alveolar bone grafting.

Unconventional implants for distal cantilever fixed full-arch prostheses: a long-term evaluation of four cases

Excessive cantilever lengths of fixed implant-supported prostheses may have functional and biomechanical disadvantages. This study reports the clinical outcomes of unconventional implants placed for distal support of a fixed implant-supported prostheses. Seven extraoral implants with intraosseous lengths of 2.5 to 4.0 mm were placed in four patients. Distal cantilevers had a mean length of 29.8 mm (range, 18.6 to 39.3 mm). No bone loss or other adverse events were found. The prosthetic plan was maintained in all patients. Within the limits of the employed research design, this concept seems to be a successful option for fixed complete implant-supported prosthesis treatment.

Dental arch relationship in 5-year-olds with complete unilateral cleft lip and palate after early alveolar bone grafting

To evaluate dental arch relationship in preschoolers with unilateral cleft lip and palate after early alveolar bone grafting (ABG).

Photographs of dental casts or digital models: rating dental arch relationships in bilateral cleft lip and palate

Yardsticks have been developed to measure dental arch relations in cleft lip and palate (CLP) patients as diagnostic proxies for the underlying skeletal relationship. Travelling with plaster casts to compare results between CLP centres is inefficient so the aim of this study was to investigate the reliability of using digital models or photographs of dental casts instead of plaster casts for rating dental arch relationships in children with complete bilateral cleft lip and palate (CBCLP). Dental casts of children with CBCLP (n=20) were included. Plaster casts, digital models and photographs of the plaster casts were available for all the children at 6, 9, and 12 years of age. All three record formats were scored using the bilateral cleft lip and palate (BCLP) yardstick by four observers in random order. No significant differences were found for the BCLP yardstick scores among the three formats. The interobserver weighted kappa scores were between 0.672 and 0.934. Comparison between the formats per observer resulted in weighted kappa scores between 0.692 and 0.885. It is concluded that digital models and photographs of dental casts can be used for rating dental arch relationships in patients with CBCLP. These formats are a reliable alternative for BCLP yardstick assessments on conventional plaster casts.

Transposition of the supra-aortic vessels before stent grafting the aortic arch and descending aorta

Thoracic endovascular aortic repair has broadened the spectrum of treatment options for various acute and chronic thoracic aortic diseases. In clinical practice, aneurysms of the descending aorta are rarely limited to 1 segment. Thus, various surgical and endovascular options have been developed to offer treatment to those patients with more extended descending thoracic aortic disease. We have summarized the most common methods of arch rerouting, depending on the aortic involvement, emphasizing that these techniques should be used very selectively by experienced cardiovascular surgery teams.