Modified Law method and Schuller method. for TMJ

Question 1

What are the clinical indications for the Modified Law Method?

Answer 1

Abnormal relationship or range of motion between condyle and TM fossa.

Generally, images are obtained in the open mouth and closed mouth positions.

Question 2

What is the patient position for the Modified Law Method?

Answer 2

• The patient should be erect or semiprone (erect is preferred if the patient’s condition allows), with the lateral aspect of the head against the table/upright imaging device surface, with the side of interest closest to the IR.

Question 2

What is the central ray (CR) alignment for the Modified Law Method?

Answer 2

• Angle CR 15° caudad, centered to 1.5 inches (4 cm) superior to the upside EAM (to pass through the downside TMJ). Center IR to projected CR.

Question 2

How should the part be positioned for the Modified Law Method?

Answer 2

• Prevent tilt by maintaining IPL perpendicular to IR.
• MSP is parallel to IR to start.
• Align IOML perpendicular to the front edge of the IR.
• From a lateral position, rotate the face toward the IR 15° (with MSP of the head rotated 15° from the plane of IR).

Question 3

What are the clinical indications for the Schuller Method?

Answer 3

Abnormal relationship or range of motion between condyle and TM fossa.

Generally, images are obtained in the open mouth and closed mouth positions.

Question 4

Q: What are the technical factors for the Schuller Method? A:

Answer 4

Minimum SID: 40 inches (102 cm)

IR size: 18 × 24 cm (8 × 10 inches), lengthwise

Grid

Analog: 70 to 80 kV range

Digital systems: 75 to 85 kV range

AEC not recommended

Question 6

How should shielding be applied in the Schuller Method?

Answer 6

Shield radiosensitive tissues outside the region of interest.

Question 7

How should the part be positioned for the Schuller Method?

Answer 7

Adjust the head into a true lateral position and move the patient’s body in an oblique direction for comfort.

Align IPL perpendicular to IR.

Align MSP parallel with the table/imaging device surface.

Position IOML perpendicular to the front edge of IR.

Question 8

What is the central ray (CR) alignment for the Schuller Method?

Answer 8

Angle CR 25° to 30° caudad, centered to 0.5 inches (1.3 cm) anterior and 2 inches (5 cm) superior to the upside EAM. Center IR to the projected TMJ.

Question 9

What is a notable difference between the Schuller Method and the Modified Law Method?

Answer 9

The Schuller Method results in greater elongation of the condyle compared with the Modified Law Method.