Fem and Von Mises analysis of OSSTEM ® dental implant structural components: evaluation of different direction dynamic loads

Abstract PURPOSE: The objective of this investigation is to study prosthodontics and internal components resistance to the masticatory stress and considering different force directions by using Finite Element Method analysis (FEM). The structural materials of the components are usually Titanium alloy grade 4 or 5 and thus, guarantee the integration of the fixture in the bone due to the osteointegration phenomena. Even if the long-term dental implant survival rate is easy to be obtained and confirmed by numerous researches, the related clinical success, due to the alteration of the mechanical and prosthodontics components is still controversial. METHODS: By applying engineering systems of investigations like FEM and Von Mises analyses, it has been investigated how dental implant material was held against the masticatory strength during the dynamic masticatory cycles. A three-dimensional system involved fixture, abutment and the connection screws, which were created and analyzed. The elastic features of the materials used in the study were taken from recent literature data. RESULTS: Data revealed a different response for both types of devices, although implant neck and dental abutment showed better results for all conditions of loading while the abutment screw represented aweak point of the system. CONCLUSION: The data of this virtual model showed all the features of different prosthetic retention systems under the masticatory load. Clinicians should find better prosthetic balance in order to better distribute the stress over the component and to guarantee patients' clinical long-term results

Prevalence of congenital muscular dystrophy in Italy: A population study.

OBJECTIVE: We provide a nationwide population study of patients with congenital muscular dystrophy in Italy. METHODS: Cases were ascertained from the databases in all the tertiary referral centers for pediatric neuromuscular disorders and from all the genetic diagnostic centers in which diagnostic tests for these forms are performed. RESULTS: The study includes 336 patients with a point prevalence of 0.563 per 100,000. Mutations were identified in 220 of the 336 (65.5%). The cohort was subdivided into diagnostic categories based on the most recent classifications on congenital muscular dystrophies. The most common forms were those with α-dystroglycan glycosylation deficiency (40.18%) followed by those with laminin α2 deficiency (24.11%) and collagen VI deficiency (20.24%). The forms of congenital muscular dystrophy related to mutations in SEPN1 and LMNA were less frequent (6.25% and 5.95%, respectively). CONCLUSIONS: Our study provides for the first time comprehensive epidemiologic information and point prevalence figures for each of the major diagnostic categories on a large cohort of congenital muscular dystrophies. The study also reflects the diagnostic progress in this field with an accurate classification of the cases according to the most recent gene discoveries

1-Year Outcomes After Transfemoral Transcatheter or Surgical Aortic Valve Replacement: Results From the Italian OBSERVANT Study.

BACKGROUND: There is a paucity of prospective and controlled data on the comparative effectiveness of transcatheter aortic valve replacement (TAVR) versus surgical aortic valve replacement (SAVR) in a real-world setting. OBJECTIVES: This analysis aims to describe 1-year clinical outcomes of a large series of propensity-matched patients who underwent SAVR and transfemoral TAVR. METHODS: The OBSERVANT (Observational Study of Effectiveness of SAVR-TAVI Procedures for Severe Aortic Stenosis Treatment) trial is an observational prospective multicenter cohort study that enrolled patients with aortic stenosis (AS) who underwent SAVR or TAVR. The propensity score method was applied to select 2 groups with similar baseline characteristics. All outcomes were adjudicated through a linkage with administrative databases. The primary endpoints of this analysis were death from any cause and major adverse cardiac and cerebrovascular events (MACCE) at 1 year. RESULTS: The unadjusted enrolled population (N = 7,618) included 5,707 SAVR patients and 1,911 TAVR patients. The matched population had a total of 1,300 patients (650 per group). The propensity score method generated a low-intermediate risk population (mean logistic EuroSCORE 1: 10.2 ± 9.2% vs. 9.5 ± 7.1%, SAVR vs. transfemoral TAVR; p = 0.104). At 1 year, the rate of death from any cause was 13.6% in the surgical group and 13.8% in the transcatheter group (hazard ratio [HR]: 0.99; 95% confidence interval [CI]: 0.72 to 1.35; p = 0.936). Similarly, there were no significant differences in the rates of MACCE, which were 17.6% in the surgical group and 18.2% in the transcatheter group (HR: 1.03; 95% CI: 0.78 to 1.36; p = 0.831). The cumulative incidence of cerebrovascular events, and rehospitalization due to cardiac reasons and acute heart failure was similar in both groups at 1 year. CONCLUSIONS: The results suggest that SAVR and transfemoral TAVR have comparable mortality, MACCE, and rates of rehospitalization due to cardiac reasons at 1 year. These data need to be confirmed in longer term and dedicated ongoing randomized trials