A periodontal curette is a dental instrument used primarily in the prophylactic and periodontal

Periodontology

Periodontology or Periodontics is the specialty of dentistry that studies supporting structures of teeth, diseases, and conditions that affect them...

 care of human teeth. The working tips are fashioned in a variety of shapes and sizes, but they are always rounded at the tip in order to make subgingival cleansing less traumatic to the gingiva

Gingiva

The gingiva , or gums, consists of the mucosal tissue that lies over the mandible and maxilla inside the mouth.-General description:...

. Periodontal scaler

Periodontal scaler

Periodontal scalers are dental instruments used primarily in the prophylactic and periodontal care of human teeth. The working ends come in a variety of shapes and sizes, but they are always narrow at the tip, so as to allow for access to narrow embrasure spaces between teeth...

s feature a sharp tip to access supragingival calculus

Calculus (dental)

In dentistry, calculus or tartar is a form of hardened dental plaque. It is caused by the continual accumulation of minerals from saliva on plaque on the teeth...

 in tight embrasure spaces, thus making the curette the choice instrument for treating subgingival areas of calculus accumulation.

Curettes are best used when the terminal shank, namely, the last portion of the handle attached to the blade, is held parallel

Parallel (geometry)

Parallelism is a term in geometry and in everyday life that refers to a property in Euclidean space of two or more lines or planes, or a combination of these. The assumed existence and properties of parallel lines are the basis of Euclid's parallel postulate. Two lines in a plane that do not...

 to the long axis of the tooth. To facilitate proper usage, instruments often come with posterior analogs which possess angled terminal shanks.

Classically, there are two recognized groups of curettes.

• A universal curette has a blade that is perpendicular to its terminal shank. This orientation allows the blade to be used against either the mesial or distal surface of a tooth. Because this type of periodontal curette was developed at the Columbia University College of Dental Medicine
  Columbia University College of Dental Medicine
  The Columbia University College of Dental Medicine, often abbreviated CDM, is one of fourteen graduate and professional schools of Columbia University...
  
  , it is also known as a Columbia curette.
• The Gracey curette, invented by Dr Clayton Gracey with the help of Hugo Friedman of Hu-Friedy Manufacturing company in the early 1940's, has a blade that is laterally offset by 70 degrees relative to the shank. Consequently, a Gracey curette has a lower cutting edge and an upper non-cutting edge. Because only one side of each blade can cut, Gracey curettes are site-specific, and a posterior instrument used to clean mesial
  Commonly used terms of relationship and comparison in dentistry
  There are numerous commonly used terms of relationship and comparison that refer to different aspects of teeth and are frequently utilized in articles about dentistry...
  
   surfaces of teeth will not work on distal
  Commonly used terms of relationship and comparison in dentistry
  There are numerous commonly used terms of relationship and comparison that refer to different aspects of teeth and are frequently utilized in articles about dentistry...
  
   surfaces, and vice versa. "Gracey" Christina Patrick blades used for mesial surfaces of anterior
  Commonly used terms of relationship and comparison in dentistry
  There are numerous commonly used terms of relationship and comparison that refer to different aspects of teeth and are frequently utilized in articles about dentistry...
  
   teeth from the facial
  Commonly used terms of relationship and comparison in dentistry
  There are numerous commonly used terms of relationship and comparison that refer to different aspects of teeth and are frequently utilized in articles about dentistry...
  
   are only suitable for the distal surfaces of the same teeth when access is performed from the lingual
  Commonly used terms of relationship and comparison in dentistry
  There are numerous commonly used terms of relationship and comparison that refer to different aspects of teeth and are frequently utilized in articles about dentistry...
  
  . Gracey Curettes 1/2, 3/4, 5/6 are used on the anterior sextants of teeth. 7/8 and 9/10 are used on the buccal and lingual portions of posterior teeth. 11/12 and 15/16 are used on the mesial portions of posterior teeth. 13/14 and 17/18 are used on the distal portions of posterior teeth.