Search results for "RESTORATION"

DIAGNOSTICS FOR CULTURAL HERITAGE: ANALYTICAL APPROACH FOR AN EFFECTIVE CONSERVATION

2014

Imaging Cultural Heritage at Different Scales: Part I, the Micro-Scale (Manufacts)

2023

Applications of non-invasive sensing techniques to investigate the internal structure and surface of precious and delicate objects represent a very important and consolidated research field in the scientific domain of cultural heritage knowledge and conservation. The present article is the first of three reviews focused on contact and non-contact imaging techniques applied to surveying cultural heritage at micro- (i.e., manufacts), meso- (sites) and macro-scales (landscapes). The capability to infer variations in geometrical and physical properties across the inspected surfaces or volumes is the unifying factor of these techniques, allowing scientists to discover new historical sites or to …

Vulnerability of a Damaged Bridge Abutment in a Seismic Area

2018

The case of the abutment of a motorway urban viaduct damaged by human intervention is presented. Built in the 1960s, it lies in a critical seismic area and the human-induced damage involved the elements of the abutment foundation. The structure is geometrically complex and the evaluations of its structural safety were carried out by applying Italian codes from different times: those concerning the time of construction, those of a recent past (1996), and those of the present (2008), inspired by Eurocodes. A comparison between the safety checks performed and the requirements of all these codes is presented and discussed, especially regarding safety coefficients after the damage was done. Two …

Narrow-diameter implants: A systematic review and meta-analysis.

2018

OBJECTIVES Narrow-diameter implants (NDI) are claimed to be a reasonable alternative to bone augmentation procedures. The aim of this comprehensive literature review was to conduct a meta-analysis comparing the implant survival of NDI and standard diameter implants (SDI) and to provide recommendations and guidelines for application of NDI. MATERIAL AND METHODS An extensive systematic literature search was performed in the PubMed/MEDLINE and the Cochrane Library databases. NDI were classified into Category 1 (implant diameter <3.0 mm, "mini-implants"), Category 2 (implant diameter 3-3.25 mm) and Category 3 (implant diameters 3.3-3.5 mm). Clinical studies at all levels of evidence with at lea…

Optical calibration of a multispectral imaging system based on interference filters

2005

We present a new approach to optically calibrate a multispectral imaging system based on interference filters. Such a system typically suffers from some blurring of its channel images. Because the effectiveness of spectrum reconstruction depends heavily on the quality of the acquired channel images, and because this blurring negatively affects them, a method for deblurring and denoising them is required. The blur is modeled as a uniform intensity distribution within a circular disk. It allows us to characterize, quantitatively, the degradation for each channel image. In terms of global reduction of the blur, it consists of the choice of the best channel for the focus adjustment according to…

Quasi-Newton approach to nonnegative image restorations

2000

Abstract Image restoration, or deblurring, is the process of attempting to correct for degradation in a recorded image. Typically the blurring system is assumed to be linear and spatially invariant, and fast Fourier transform (FFT) based schemes result in efficient computational image restoration methods. However, real images have properties that cannot always be handled by linear methods. In particular, an image consists of positive light intensities, and thus a nonnegativity constraint should be enforced. This constraint and other ways of incorporating a priori information have been suggested in various applications, and can lead to substantial improvements in the reconstructions. Neverth…

THE SAN VITO WOODEN PULPIT FROM MUSEO DIOCESANO OF PALERMO, ITALY: MULTIDISCIPLINARY APPROACH AND ANALYTICAL TECHNIQUES FOR DATING AND RESTORATION

2017

The aim of the present research is to investigate the constitutive materials and the execution techniques of San Vito wooden pulpit from Museo Diocesano of Palermo (Italy) and to provide helpful information to dating it in addition to technical, historical and artistic evaluations. The pulpit, attributed to unknown artist, belongs to the decorative arts and the most relevant feature is its double dating, in addition to the singular painting technique: it has a linear structure typical of XIXth century and three polychrome and gilded panels probably dated to the end of XVIIth century. This paper describes the application of analytical techniques (imaging diagnostics techniques, Scanning Elec…

Risk factors associated with early failure of dental implants. A literature review

2010

The aim of the study was to examine articles published on risk factors associated with early failure of dental implants. We conducted a search on PubMed for articles published between January 2000 and December 2009 using the keywords 'dental implants' and 'early failure'. Seven studies that specified the number of early failed implants and studied the associated risk factors were included. Early failures are caused by the inability of tissue to establish osseointegration prior to prosthetic restoration; however the causal factors and mechanisms are unclear. In the reviewed literature there was a higher percentage of early than late failures; nevertheless, few articles were found that analyz…

A Prospective Noninterventional Study to Evaluate Survival and Success of Reduced Diameter Implants Made From Titanium-Zirconium Alloy

2015

Narrow diameter implants may be at increased risk of overload due to occlusal forces; therefore, implants with higher fatigue strength may be beneficial. The aim of this observational study was to evaluate survival and success of narrow diameter (Ø 3.3 mm) TiZr alloy (Roxolid, Institut Straumann AG, Basel, Switzerland) implants for 2 years in daily dental practice. This was a prospective, non-interventional, multicenter study; no specific patient inclusion or exclusion criteria were applied. Each patient received at least one TiZr implant; the treatment plan, including implant loading and final restoration, was at the investigator's discretion. The primary outcome was implant survival and s…

Meta-analysis on the survival of short implants

2010

Objective: To evaluate the success and failure rates of short implants (10 mm or less) for oral rehabilitations in cases of limited bone height. Study Design: Review of the articles published on the topic between the years 2000 and 2010, and development of a descriptive meta-analysis of the results. Results: The majority of the studies obtain a cumulative success rate (CSR) similar to that of longer implants (92.5% - 98.42% for machined and rough-surface implants, respectively). The studies that record lower cumulative success rates (CSR) are later studies that analyze implants with a machined surface. Almost none of the studi-es compared the success/failure rates with the bone quality or l…