Hygiene Atlas

Atlas · Plate XI · Instrumentation · 04

Adaptation and angulation

Keep the leading third of the working end against the tooth. Insert the blade closed, near 0 degrees, then open to a working angle of 45-90 degrees, about 60-80 for calculus removal. Below 45 degrees the edge burnishes calculus; above 90 it tears the pocket lining. Strokes run vertical, oblique or horizontal, and posterior teeth are worked from the distal line angle toward the mesial.

High-yield facts · 8

  1. Adaptation: keep the leading third (toe or tip third) of the working end in contact with the tooth.T3
  2. Insertion angle near 0 degrees (face toward the tooth) to slide under the gingival margin.T3
  3. Working angle 45-90 degrees; 60-80 degrees for calculus removal; 60-70 degrees for lighter root debridement.T3
  4. Under 45 degrees: the edge slides over and burnishes calculus. Over 90 degrees: the edge tears the pocket lining.T3
  5. Activation: wrist-rocking with a pivot on the fulcrum; digital (finger flexing) activation is for limited areas.T3
  6. Stroke types: assessment (light, longer), calculus removal (short, firm, controlled), root debridement (lighter, overlapping).T3
  7. Stroke directions: vertical, oblique, horizontal (circumferential); horizontal strokes help at line angles, furcations and deep narrow pockets.T3
  8. Line-angle rule: instrument posterior teeth from the distal line angle toward the mesial; anterior teeth from the midline outward.T3

Facts are written in our own words; each tag links to its source. Values marked "sources vary" differ between references, so check the one your program uses.