Trace amounts of host, dietary, and environmental microdebris are also found within calculus, including salivary proteins, plant DNA, milk proteins, starch granules, textile fibers, and smoke particles. Calculus formation
The processes of calculus formation from dental plaque are not well understood. Supragingival calculus formation is most abundant on the buccal (cheek) surfaces of the maxillary (upper jaw) molars and on the lingual (tongue) surfaces of the mandibular (lower jaw) incisors. These areas experience high salivary flow because of their proximity to the parotid and sublingual salivary glands. Subgingival calculus forms below the gumline and is typically darkened in color by the presence of black-pigmented bacteria, whose cells are coated in a layer of iron obtained from heme during gingival bleeding. Dental calculus typically forms in incremental layers that are easily visible using both electron microscopy and light microscopy. These layers form during periodic calcification events of the dental plaque, but the timing and triggers of these events are poorly understood. The formation of calculus varies widely among individuals and at different locations within the mouth. Many variables have been identified that influence the formation of dental calculus, including age, gender, ethnic background, diet, location in the oral cavity, oral hygiene, bacterial plaque composition, host genetics, access to professional dental care, physical disabilities, systemic diseases, tobacco use, and drugs and medications. Clinical significance
Plaque accumulation causes the gingiva to become irritated and inflamed, and this is referred to as gingivitis.
Each type of tool is designed to be used in specific areas of the mouth. Some commonly used instruments include sickle scalers which are designed with a pointed tip and are mainly used supragingivally. Curettes are mainly used to remove subgingival calculus, smooth root surfaces and to clean out periodontal pockets. Curettes can be divided into two subgroups: universals and area specific instruments. Universal curettes can be used in multiple areas, while area specific instruments are designed for select tooth surfaces. Gracey curettes are a popular type of area specific curettes. Due to their design, area specific curettes allow for better adaptation to the root surface and can be slightly more effective than universals. Hoes, chisels, and files are less widely used than scalers and curettes. These are beneficial when removing large amounts of calculus or tenacious calculus that cannot be removed with a curette or scaler alone. Chisels and hoes are used to remove bands of calculus, whereas files are used to crush burnished or tenacious calculus.For hand instrumentation to be effective and efficient, it is important for clinicians to ensure that the instruments being used are sharp. It is also important for the clinician to understand the design of the hand instruments to be able to adapt them properly.Ultrasonic scalers, also known as power scalers, are effective in removing calculus, stain, and plaque. These scalers are also useful for root planing, curettage, and surgical debridement.