It is common to lie back in the dental chair and hear a rapid-fire sequence of numbers called out by the hygienist or dentist to an assistant. These digits are not a secret code but a systematic way of recording the health of your gums and surrounding bone structure. This process, known as periodontal charting, is a fundamental part of a comprehensive dental examination. The numbers provide a snapshot of your oral health, allowing the dental team to track changes over time.
How Dentists Identify Specific Teeth
Before any measurements are recorded, the dental team needs a standardized way to identify which tooth is being examined. In the United States, the most widely used method is the Universal Numbering System, which assigns a number from 1 to 32 to your permanent teeth. This system ensures clear communication between all dental professionals about a specific location in your mouth.
The numbering sequence begins with the upper-right third molar, or wisdom tooth, designated as number 1. The numbers proceed sequentially across the upper arch to the upper-left third molar, number 16. The sequence then drops down to the lower-left third molar, number 17, and continues across the lower arch, ending at the lower-right third molar, number 32. Even if a tooth is missing, its number is still accounted for to maintain an accurate record of your dental anatomy.
Interpreting Periodontal Pocket Measurements
The primary numbers you hear being called out refer to the depth of the spaces between your teeth and your gums, measured in millimeters. A small measuring instrument called a periodontal probe is gently inserted into this space, known as the sulcus or pocket. The measurement is taken from the top of the gum tissue down to where the gum attaches to the tooth root.
A healthy measurement falls within the range of 1 to 3 millimeters, indicating that the gum tissue is fitting snugly around the tooth. In this range, the space is shallow enough for effective cleaning with routine brushing and flossing. When the number reaches 4 millimeters, it suggests the space is deepening, often due to inflammation caused by plaque and bacteria.
Readings of 4 millimeters or more are a sign of potential gum disease, as these deeper pockets are harder to keep clean at home. Measurements of 5 millimeters or greater often indicate periodontitis, which involves damage to the underlying bone supporting the teeth. The dental team takes six separate measurements around every tooth—three on the cheek side and three on the tongue side—to create a detailed map of gum health. Tracking these numbers over time monitors whether gum health is improving, remaining stable, or worsening.
Other Key Health Indicators Called Out
In addition to pocket depths, the dental team records several other indicators that complete the picture of your periodontal health. One of the most common is “Bleeding on Probing” (BOP), noted if the gum tissue bleeds when the probe is inserted. Bleeding is a direct sign of inflammation and is often recorded with a specific mark on the chart, even if the pocket depth is in the healthy range.
Another measurement is Gingival Recession, which refers to how far the gum tissue has pulled away from the tooth surface. This measurement is important because it exposes the tooth’s root surface, which is softer than the enamel and more susceptible to wear and decay. The chart also includes notations for Calculus, which is hardened plaque or tartar buildup that requires professional removal.
Finally, the dentist may call out a Mobility score to indicate how loose a tooth is, which signals bone loss around the root. Mobility is graded on a scale, where a score of 1 indicates slight movement, and higher numbers suggest more significant movement in the socket. These supplementary notes, combined with pocket depth measurements, provide the comprehensive data needed for a precise diagnosis and personalized treatment plan.