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McNamara Twin Block

The McNamara Twin Block is Dr. James McNamara's modification with acrylic over the lower labial bow and ball clasps on the lower arch for retention.

Class II Correction

McNamara Twin Block

Upper and lower removable appliances meet on bite blocks, so the patient closes with the mandible forward. Our standard uses ball and Adams clasps on the upper, and a lower labial bow with acrylic plus ball clasps. Screws are optional, so add midline or sagittal screws only when the case needs them.

Anchorage
Removable, clasp-retained
Patient age
Growing patients
Correction
Skeletal Class II
Compliance
Required, removable
Turnaround
10 business days or faster

When it’s the right call.

Use it when
Skeletal Class II pattern in a growing patient
Mandibular retrusion you want to treat during growth
Deep bite alongside a Class II molar relationship
Cases where you want vertical control from the bite blocks
Consider another appliance when
Compliance is a concern and you need a fixed corrector See Specialty Miniscope® Herbst
You prefer a one-piece removable functional appliance See The Bionator
You want fixed advancement with no rods or tubes See MARA

Options you can prescribe.

Clasping

Upper ball and Adams clasps, lower labial bow with acrylic and ball clasps. Fully customizable.

Screws

None as standard. Add midline or sagittal screws.

Bite design

Design it to open, maintain or close the bite.

Acrylic color

Choose from our standard colors. No custom designs.

Still deciding which Class II corrector?

Fixed or removable, telescoping or not, and how much you want to depend on the patient. Those three choices narrow most Class II cases to one appliance.

What every
McNamara Twin Block case needs.

Send these with the case and it goes straight onto the bench. If anything’s missing, we call you before we start.

Upper and lower digital scans, or stone models if you work on stone
A construction bite at the advancement and vertical opening you want
The completed Rx sheet, with your design choices marked
Your requested return date, so we schedule the case back from it

Resources for the McNamara Twin Block

The Rx sheet, instructions for use and chairside guides, ready to download or share with your team.

More Class II correctors.

View All Class II Correction
FAQ

Questions about the McNamara Twin Block.

Dr. McNamara added acrylic to the lower labial bow for extra retention, and the lower arch uses ball clasps.

Yes. Add midline screws to the upper or lower when the case needs lateral arch development, or sagittal screws for arch length.

Yes. Tell us on the Rx whether the design should open, maintain or close the bite.

Yes, from our standard colors. We don't make custom designs on this appliance.

Haas, top view Distal Jet, top view MARPE 4 eyelet, front view

Send us your
next case.

Appliances that fit the first time and arrive on time.