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free gingiva is the narrow band of gum tissue that forms the visible gumline around each tooth. It is the part of the gingiva (gums) that is not firmly attached to the underlying bone. It creates the outer wall of the natural space between tooth and gum called the gingival sulcus. Dentists use the free gingiva as a key landmark during exams, cleanings, and many restorative procedures near the gumline.

attached gingiva is the firm, pink gum tissue that is tightly bound to the underlying bone around teeth. It sits between the free (marginal) gingiva near the gumline and the more movable lining tissue farther down. It is part of the “keratinized gingiva,” meaning its surface is tougher and more resistant to rubbing and chewing forces. It is commonly discussed in periodontal exams, treatment planning, and when evaluating gum recession risk or comfort during brushing.

keratinized gingiva is the band of firm gum tissue around teeth (and sometimes around implants) that has a keratinized surface layer. It typically extends from the gum margin to the mucogingival junction, and includes the free gingiva and attached gingiva. In plain terms, it is the tougher, more “skin-like” gum that helps tolerate chewing and brushing forces. Clinicians discuss keratinized gingiva when assessing gum health, recession risk factors, comfort with brushing, and soft-tissue conditions around implants.

Cairo classification is a clinical system used to describe gum recession (gingival recession) in a standardized way. It groups recession defects into categories based on whether there is attachment loss between teeth (interdental clinical attachment loss). Dentists and periodontists commonly use it during periodontal examinations and when discussing root coverage planning. It helps clinicians communicate findings clearly in charts, referrals, and research.

Miller classification is a clinical system used to describe gum recession (gingival recession) around teeth. It groups recession into Classes I–IV based on how far the gum has moved and what support tissues remain. Dentists and periodontists commonly use it during periodontal (gum) examinations and treatment planning. It helps communicate findings in a standardized way across clinicians, patients, and records.

gingival recession is the apical (downward) shift of the gum margin that leaves more tooth or root surface exposed. It is a clinical finding, not a single disease, and it can occur with or without periodontal disease. It is commonly discussed in general dentistry and periodontics because it can affect comfort, aesthetics, and cavity risk on roots. Clinicians use the term to describe what they see, measure it over time, and communicate treatment options.

CAL is a term some dental teams use to refer to a light-cured, resin-based composite material used in conservative restorations. It is commonly associated with a “flowable” or “injectable” composite layer placed to adapt to small spaces and fine details. CAL is used in everyday restorative dentistry for small fillings, repairs, and as a thin liner under other composite materials. Exact meaning and product selection can vary by clinician and case.

clinical attachment level is a clinical measurement that estimates how much periodontal (gum and supporting) attachment a tooth has lost or gained. It is most commonly measured with a periodontal probe during a gum examination. It helps describe periodontal disease severity more consistently than pocket depth alone. It is used in patient records, periodontal charting, and periodontitis staging/grading discussions.

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.