The aims of this study were to determine the fracture origins and crack paths in the porcelain of clinically failed bilayer ceramic restorations and to reveal the correlation between the porcelain failures and material properties. Three clinically failed crowns of each material (bilayer zirconia crowns, galvano-ceramic crowns, and porcelain-fused-to-metal crowns) were collected and underwent fa...

We propose and demonstrate an on-chip optical correlator, in which two types of photonic crystal slow-light waveguides are integrated and operated as an optical delay scanner and a two-photon-absorption photodetector. The footprint of the device, which was fabricated using a CMOS-compatible process, was 1.0 × 0.3 mm(2), which is substantially smaller than that of conventional optical correlator...

Dental hard tissue is subject to variety of disorders. Dentinogenesis Imperfecta is one such disorder attributed to heredity. It is known to be an autosomal dominant trait. Teeth with such 'imperfect' dentin are liable to be weak and discolored. The disease has variable penetration and therefore can be expressed as a range of phenotypic manifestations from mild discoloration and chipping to fra...

It is with great regret we have to record the death of Dr. Edward Mills Grace, which took place on May 20th at Thornbury, after some months of failing health. He was born at Downend on November 28th, 1841, the third son of Henry Mills Grace, a very hard-working country doctor, whose leisure moments in the summer were given up to cricket. The other sons were Henry, Alfred, now at Chipping Sodbur...

Doctor Ingeniero de Montes, ICONA Forest Fire Section, Madrid Spain. Abstract: Forest fuels in the Mediterranean ecosystems of Spain are characterized by generalized pyrophytism and large accumulations of woody shrub vegetation. The Forest Service prepared in 1978 a fuel management plan and a program of surveys including: A study on the vegetation's evolution in forests after fires; the experim...

This article describes a technique for preparing the bed for autologous bone grafting in nonunion surgery. The procedure is divided into 2 steps. First, both ends of the fracture fragments are chipped into small pieces using an osteotome and hammer without peeling off the periosteum, creating pathways into the bone marrow. Second, cancellous bone harvested from the iliac crest is grafted into t...

Osteogenesis imperfecta is a syndrome of interest to dentists because dentinogenesis imperfecta is frequently associated with not only bone disease but also tooth diseas~. Specifically, these patients usually have many dental problems such as 1) high incidence of tooth fracture, enamel chipping and cracking, 2) high caries activity, 3) inability or difficulty of endodontic treatment, 4) mastica...

Dental enamel is prone to damage by chipping with large hard objects at forces that depend on chip size and enamel toughness. Experiments on modern human teeth have suggested that some ante-mortem chips on fossil hominin enamel were produced by bite forces near physiological maxima. Here, we show that equivalent chips in sea otter enamel require even higher forces than human enamel. Increased f...