PD is a shorthand term that may appear in some dental notes to refer to a tooth-colored, resin-based restorative material used for direct repairs. In this article, PD refers to a light-cured resin composite placed directly onto a tooth to restore or seal small areas. PD is commonly used in routine restorative dentistry for small fillings, repairs, and as an adaptation layer under other composites. The exact meaning of PD can vary by clinic, charting system, and manufacturer terminology.

probing depth is a measurement of how deep the space is between the gum and the tooth (or implant). It is measured with a thin, marked instrument called a periodontal probe during a gum exam. Clinicians use probing depth to help assess gum health and detect periodontal (gum) disease. It is commonly recorded as part of a periodontal charting at dental checkups and hygiene visits.

BOP most commonly refers to a **bite-opening pad** used in orthodontics. It is a small, raised addition of tooth-colored resin placed on selected teeth to **change how the bite contacts**. BOP is commonly used during **braces or clear aligner treatment** to create space and reduce unwanted tooth-to-tooth or tooth-to-bracket contact. The material is often a **light-cured composite resin**, similar in broad category to many filling materials.

bleeding on probing is bleeding that occurs when a clinician gently inserts a periodontal probe along the gumline. It is recorded during periodontal (gum) examinations in dental offices and clinics. It is used as a clinical sign of inflammation in gum tissues around teeth and implants. It is typically documented site-by-site during periodontal charting.

supragingival calculus is hardened dental plaque (often called “tartar”) that sits **above the gumline** on tooth surfaces. It forms when soft plaque mineralizes, becoming a rough, firmly attached deposit. It is commonly seen on teeth near salivary duct openings and around areas that retain plaque. Clinically, it is used as a descriptive finding during dental exams and cleanings.

subgingival calculus is a hardened mineral deposit (tartar) that forms on tooth surfaces below the gumline. It develops when dental plaque absorbs minerals and becomes calcified over time. Because it sits under the gums, it is usually not visible without dental instruments. It is most commonly discussed in periodontal (gum) evaluation and professional cleanings.

tartar is the common name for dental calculus, a hard deposit that forms on teeth when plaque mineralizes. It is made from bacteria, proteins, and minerals from saliva and gum fluid that harden over time. tartar most often builds up near the gumline and between teeth, and it can also form below the gums. It is commonly discussed in dental cleanings, periodontal (gum) care, and cavity-risk assessments.

calculus is hardened dental plaque (a mineralized biofilm) that forms on teeth and along the gumline. It is commonly called “tartar” in everyday language. calculus is most often discussed in preventive dentistry and periodontal (gum) care. Clinicians identify and remove calculus because it can make plaque control harder and can contribute to gum inflammation.

biofilm is a structured layer of microorganisms that sticks to a surface and protects itself with a slimy matrix. In the mouth, biofilm commonly forms on teeth, gums, restorations, and dental implants. Dental “plaque” is a familiar example of biofilm. The term is used in everyday dentistry, hygiene care, and clinical research on cavities and gum disease.

dental plaque is a sticky, living film (biofilm) made of bacteria and their protective matrix. It forms on teeth, gums, dental restorations, and orthodontic appliances. In clinics, it is discussed because it contributes to cavities and gum inflammation when it accumulates. It is also “used” as a clinical indicator to assess oral hygiene and disease risk.