Bleaching of nonvital teeth: a clinically relevant literature review

Today, the bleaching of nonvital, discolored teeth is a low-risk routine treatment for improving esthetics. This review article focuses on the etiology of tooth discolorations, different treatment techniques, and risks of bleaching procedures. Some tooth discolorations in endodontically treated teeth are caused by dental treatments. The three most popular techniques for nonvital tooth bleaching are the walking bleach technique, inside/outside bleaching, and in-office bleaching. The walking bleach technique is a relatively reliable, fairly simple technique for dentists and patients. Inside/outside bleaching can be used additionally when internal and external bleaching must be combined. Inoffice bleaching seems to be a short-term solution, the effects of which can largely be attributed to dehydration of the teeth. There are still some open questions concerning the bleaching agents. Improved safety seems desirable with regard to adding thiourea as a scavenger of radicals or newer materials such as sodium percarbonate. The thermocatalytic technique, insufficient cervical sealing, and high concentrations of bleaching agents should be avoided, as this can increase the risk of cervical root resorptions. Patients should be informed about the low predictability of bleaching success and the risk of recurrent discoloration. The risk of cervical root resorption should be discussed with the patient. There is a strong correlation between root resorption and dental trauma.

[Examination of urine in the child]

The examination of urine in children can be very complex, due to the difficulty to obtain clean urine specimens in infants and toddlers. Clean catch is an easy system to obtain urine but patience is needed. Transurethral catheterization or suprapubic aspiration is useful in infants and toddlers with sign of pyelonephritis. Urine bag specimens are not useful in the diagnosis of urinary tract infection because of the high rate of false positive cultures. The 24 hours urine collection is frequently replaced by a spot urine and the ratio of the measured substances with the urine creatinine are calculated. Urine microscopy is needed for the evaluation of pathological results in the dipstick testing: confirm that red urine is due to haematuria by demonstration of red blood cells on urine microscopy, dysmorphic cells and red-cell casts are pathognomonic of glomerular bleeding, white-cell casts signify glomerular inflammation and bacteria are easily seen in unstained urine. A urine culture is pathologic if the colony count exceeds 10(4) in the transurethral catheterization or clean void. In the suprapubic aspiration is any number of colony pathologic. Urate crystals in the urine of infants may cause a pink discoloration to nappies. Urine screenings are not very useful and should be performed only at the age of 5 years or by sexual-active adolescents.

[MRI-based diagnosis of an acute bilateral compartment syndrome]

The acute compartment syndrome describes a posttraumatic or inflammatory edema, which leads to a painful constraint of muscular movement and paresthesia. An increase in pressure in the anatomical compartment is postulated. The main symptoms include local swelling, sensory loss, local muscle weakness as well as late livid discoloration. Therapy of choice is an early fasciotomy with decompression to avoid serious complications like muscle necrosis. Here we report a 22 year old patient who postoperatively suffered from a bilateral paresis of the foot jack. Further examinations by electromyography and magnetic resonance imaging (MRI) led to the diagnosis of an acute bilateral compartment syndrome.

Fatal contact shot to the chest caused by the gas jet from a muzzle-loading pistol discharging only black powder and no bullet: case study and experimental simulation of the wounding effect.

In modern medico-legal literature, only a small number of publications deal with fatal injuries from black powder guns. Most of them focus on the morphological features such as intense soot soiling, blast tattooing and burn effects in close-range shots or describe the wound ballistics of spherical lead bullets. Another kind of "unusual" and potentially lethal weapons are handguns destined for firing only blank cartridges such as starter and alarm pistols. The dangerousness of these guns is restricted to very close and contact range shots and results from the gas jet produced by the deflagration of the propellant. The present paper reports on a suicide committed with a muzzle-loading percussion pistol cal. 45. An unusually large stellate entrance wound was located in the precordial region, accompanied by an imprint mark from the ramrod and a faint greenish discoloration (apparently due to the formation of sulfhemoglobin). Autopsy revealed an oversized powder cavity, multiple fractures of the anterior thoracic wall as well as ruptures of the heart, the aorta, the left hepatic lobe and the diaphragm. In total, the zone of mechanical destruction had a diameter of approx. 15 cm. As there was no exit wound and no bullet lodged in the body, the injury was caused exclusively by the inrushing combustion gases of the propellant (black powder) comparable with the gas jet of a blank cartridge gun. In contact shots to ballistic gelatine using the suicide's pistol loaded with black powder but no projectile, the formation of a nearly spherical cavity could be demonstrated by means of a high-speed camera. The extent of the temporary cavity after firing with 5 g of black powder roughly corresponded to the zone of destruction found in the suicide's body.