Distributions of the largest eigenvalues of Wishart covariance matrices corresponding to the large size data matrices are studied in this paper by reviewing the most recent results on this topic. Special attention is paid to the corresponding asymptotic laws – Tracy-Widom distributions, and their realizations in S-Plus. A further look at the practical aspects of the results studied in the paper...

Introducing a new hobby for other people may inspire them to join with you. Reading, as one of mutual hobby, is considered as the very easy hobby to do. But, many people are not interested in this hobby. Why? Boring is the reason of why. However, this feel actually can deal with the book and time of you reading. Yeah, one that we will refer to break the boredom in reading is choosing statistica...

Nanofillers can reduce enamel demineralization without compromising physical properties of the composite. The aim of this study was to evaluate shear bond strength (SBS) and antibacterial effects of an orthodontic composite after adding titanium oxide (TiO2) nanoparticles. Light cure orthodontic composite paste (Transbond XT) was blended with TiO2 nanoparticles. A total of 30 extracted premolar...

The aim of this in vitro study was to investigate both shear bond strength (SBS) by shear testing of indirectly bonded brackets, and the accuracy of a new transfer method, the Aptus bonding device (ABD). For comparison, the SBS of directly bonded brackets in two experimental arrangements was also measured. The precision of the positioning of the indirect bracket transfer was assessed by photogr...

BACKGROUND One of the most important complications of fixed orthodontic treatment is the formation of white spots which are initial carious lesions. Addition of antimicrobial agents into orthodontic adhesives might be a wise solution for prevention of white spot formation. The aim of this study was to evaluate the antibacterial properties of a conventional orthodontic adhesive containing three ...

Objective: The aim of this study is to evaluate the effect of six different prophylactic agents on shear bond strength (SBS) of orthodontic brackets. Materials and methods: One hundred twenty-six freshly extracted mandibular bovine incisors were used. Teeth were randomly divided into 7 equal groups (18 per group) as follows: group-1 served as control with no pre-treatment; group-2 enamel treate...

INTRODUCTION A self-etching primer (SEP) saves valuable time by eliminating the many steps required to etch, rinse, and place a sealant before application of the adhesive and placement of the bracket. The purpose of this study was to compare the effects of a conventional etch and sealant (CES) and a SEP on enamel decalcification in vivo. METHODS Twenty-five patients who required comprehensive...

The aim of this study was to compare the shear bond strength (SBS) and debonding characteristics of a polymer mesh base ceramic bracket bonded with two different surface conditioning methods. InVu Readi-Base ceramic brackets were bonded to 100 human premolars with different etching protocols. With conventional method (CM), the teeth were etched with 37 per cent phosphoric acid for 30 seconds, w...