1. Chapter 7: Ultrasonic Instrumentation Technique Modules
Furcation Module 1:
Buccal / Lingual Furcations (Left Curved Tip)

2. Buccal Furcation #3 (FDI 16)
Figure 7.62
Figure 7.62
Slim left curved tip vertically adapted at entrance of buccal furcation #3 (16).
Adapt active area of back of tip (preferred for concave anatomy) or lateral surface to entrance of furcation. Debride entrance using a series of short, overlapping horizontal or oblique strokes while advancing tip into the dome of the furcation.

3. Buccal Furcation #3 (FDI 16) Dome
Figure 7.63a
Figure 7.63b
Figure 7.63
#3 (16) dome of buccal furcation: (a) buccal perspective, note 00 angulation to dome ; (b) apical perspective. Black arrow indicates direction of working stroke.
While maintaining adaptation of active surface of tip at 0 degrees angulation to the dome, debride the dome with short, in-and-out strokes.

4. Buccal Furcation #3 (FDI 16) Dome
Figure 7.64
Figure 7.64
# 3(16) dome of buccal furcation.
In maxillary molar furcations, take care to prevent point of tip from contacting palatal root, if exposed, during debridement of the dome. In some situations, angling the tip to pass between the palatal and mesial (Fig. 7.64) or distal roots may be possible.

5. Buccal Furcation #3 (FDI 16) Distal Root
Figure 7.65a
Figure 7.65b
Figure 7.65
# 3(16) buccal furcation, internal surface of distal root: (a) buccal perspective; (b) apical perspective
From the dome, adapt the back of the tip horizontally against the internal surface of the distal root*. Maintaining horizontal adaptation, stroke the back vertically (up/down) over the internal surface of the distal root.
* If the lateral tip surface is adapted to the dome, the back of the tip is already horizontally oriented to the distal root; if the back of the tip is adapted to the dome, slightly roll tip to orient the back towards the distal root.

6. Buccal Furcation #3 (FDI 16) Mesial Root
Figure 7.66a
Figure 7.66b
Figure 7.66
#3 (16) buccal furcation, internal surface of mesial root: (a) buccal perspective; (b) apical perspective.
Retreat tip to dome and roll slightly to adapt the lateral surface of the active area horizontal to the internal surface of the mesial root.* Maintaining this horizontal orientation, stroke the lateral surface vertically over the internal surface of the mesial root.
*The ideal surface to adapt to the deeply concave internal mesial root surface is the convex back of the curved tip; but, from the buccal aspect, the back cannot be readily adapted in most situations. However, from the palatal aspect, the back of the tip is more adaptable to the internal surface of the mesial root. Therefore, when accessible, debridement of the internal surface of the mesial root should be accomplished primarily from the palatal aspect.

7. Buccal Furcation #3 (FDI 16) Mesial Root
Figure 7.67a
Figure 7.67b
Figure 7.67
#3 (16) buccal furcation, internal surface of mesial root: (a) buccal perspective showing adaptation of the face to the mesial root; (b) apical perspective showing point gouging internal surface of mesial root when face of tip is adapted.
While it may seem rationale to utilize the face of the tip to debride the internal surface of the mesial root (Fig. 7.67a), adaptation of the face is contraindicated because it inherently results in the point of the tip contacting the root structure and causing root gouging (Fig. 7.67b).