A wheeze is a continuous, coarse, whistling sound produced in the respiratory airways during breathing. For wheezes to occur, some part of the respiratory tree must be narrowed or obstructed (for example narrowing of the lower respiratory tract in an asthmatic attack), or airflow velocity within the respiratory tree must be heightened. Wheezing is commonly experienced by persons with a lung disease; the most common cause of recurrent wheezing is asthma, though it can also be a symptom of lung cancer, congestive heart failure, and certain types of heart diseases. The differential diagnosis of wheezing is wide, and the reason for  wheezing in a given patient is determined by considering the characteristics of the wheezes and the historical and clinical findings made by the examining physician. Characteristics
Wheeze
Wheezes occupy different portions of the respiratory cycle depending on the site of airway obstruction and its nature. The fraction of the respiratory cycle during which a wheeze is produced roughly corresponds to the degree of airway obstruction. Bronchiolar disease usually causes wheezing that occurs in the expiratory phase of respiration. As a rule, extrathoracic airway obstruction produce inspiratory sounds. Intrathoracic major airway obstruction produces inspiratory as well as expiratory sounds. Distal airway obstruction predominantly produces expiratory sounds.The presence of expiratory phase wheezing signifies that the patients peak expiratory flow rate is less than 50% of normal. Wheezing heard in the inspiratory phase, on the other hand, is often a sign of a stiff stenosis, usually caused by tumors, foreign bodies or scarring.
amalgam particles can contaminate dental floss and lead to linear amalgam tattoos in between the teeth, especially if flossing is carried out immediately after placement of an amalgam filling with a mesial or distal aspect
Polishing of an amalgam filling
The pressure from high speed turbine dental drills can be enough to force amalgam particles into soft tissue, as may occur when an old amalgam filling is being removed
When a tooth with an amalgam filling is extracted,: 183  e.g. broken bits of amalgam filling falling into an extraction socket unnoticed
When an amalgam filling is placed in the same appointment as a tooth extracted, as may occur in "quadrant dentistry"
Apicectomies are common causes of amalgam tattoo, since the amalgam is being placed inside the alveolus and the soft tissues are replaced on topOver time, the amalgam particles embedded in the soft tissues corrode. : 183  Macrophages take up the exogenous particles, and the silver in amalgam leads to staining of collagen fibers. : 183 A similar appearance can be caused by implantation of graphite (e.g. from pencil leads), and is sometimes termed a graphite tattoo, although this is less common than tattooing with amalgam. : 138

Diagnosis
The diagnosis is clinical. : 138  Amalgam tattoo can be distinguished from other causes of localized oral pigmentation because it does not change significantly in size or color,: 138  although it may appear to slowly enlarge for several months after the initial implantation of the metal particles. : 183  Some amalgam tattoos appear radio-opaque on radiographs (i.e.