Upper Hay Rake habit applianceresearched

Quick facts

Field	Value
ID	OA-0171
Type	habit_appliance
Category	habit_appliance
Fixed/removable	fixed
Primary function	habit interruption / myofunctional training
Related appliance	Tongue crib
Uses TADs	no

Overview

The Hay Rake uses pointed wire spurs (resembling a hay rake) projecting palatally from a transpalatal bar. When a digit is inserted, the spur tips create discomfort, deterring the habit without completely blocking access. The rake design is more aggressive than the standard crib and is used for patients with strong digit habits who are not deterred by a smooth crib. It is fixed (banded to molars) and operates 24/7.

For comprehensive research on fixed habit appliance mechanisms, fabrication, and CFL pricing, see the primary reference page: Tongue crib.

Clinical & technical

Mechanism of action

The hay rake delivers negative sensory reinforcement: when the tongue presses forward against the anterior teeth, it contacts a series of short acrylic or wire spikes (the "rake") bonded to the palatal surface or embedded in a removable baseplate. The contact is uncomfortable but not painful, and over 4–8 weeks the patient learns to redirect the tongue posteriorly to avoid contact. The appliance does not actively move teeth — it modifies neuromuscular habit by altering the sensory feedback loop associated with tongue thrust.

Indications & case selection

• Anterior tongue thrust causing anterior open bite in growing

patients (ages 5–12 preferred)

• Digital sucking with tongue protrusion component
• Post-orthodontic retention where residual tongue thrust risks

open-bite relapse

• Cases where the simpler palatal crib (Palatal crib) has failed to break the habit

Best results in patients with sufficient growth remaining. Adult patients show lower habit-modification success with passive deterrent appliances.

Contraindications & limitations

• Active periodontal disease (fixed version)
• Patients with severe gag reflex (removable version may be

preferable)

• Soft tissue pathology on the palate
• Limited patient/parent cooperation for removable versions
• Not indicated as the sole treatment for skeletal open bite — must be

combined with orthodontic tooth movement if open bite has a skeletal component

Design & fabrication

Components & materials

• Acrylic baseplate (Baseplate):

heat-cured PMMA, pink or clear

• Rake spikes: acrylic projections or bent 0.9 mm stainless steel

wire; 4–8 spikes, 3–5 mm in length, angled posteriorly

• Adams clasps (Adams clasp): on upper

first molars and often upper first premolars/canines for retention

• Labial bow (Labial bow): optional,

for anterior aesthetics and additional retention

• Fixed version: spikes soldered to a TPA wire or bonded directly to

bands on upper molars

Lab fabrication notes

Mark the palatal vault on the model. Bend stainless steel spikes (0.9 mm wire, 4–5 mm long, bent at 90°) or carve acrylic projections — 4 to 6 spikes arranged in a row 4–6 mm behind the upper incisors at the rugae area. Spikes must be firmly embedded in acrylic (minimum 4 mm embedment) and polished smooth at the base to prevent gingival irritation. Position spikes so they contact the tongue mid-thrust — too posterior and the patient avoids them before the thrust completes; too anterior and the rake can abrade the incisal mucosa.

Common variants & modifications

• Fixed hay rake: spikes soldered onto a transpalatal arch; no

patient compliance required

• Removable hay rake: acrylic baseplate with clasp retention;

patient can remove for eating/hygiene

• Rake + expansion screw: combined with Schwarz screw for

simultaneous arch development (Dillingham combination expansion/habit appliance)

• Lower rake: rarely, a mandibular version for atypical tongue

thrust patterns (Lower tongue thrust appliance)

Sources

• [Tongue Thrust and Habit Appliances — AAPD Reference

Manual](https://www.aapd.org/research/oral-health-policies--recommendations/management-of-the-developing-dentition/)

• [Orthodontic Management of Tongue Thrust —

AJO-DO](https://www.ajodo.org)

• [Removable Orthodontic Appliances — Isaacson, Muir & Reed

(Elsevier)](https://www.elsevier.com)

Research log

• 2026-06-10 — page scaffolded from Master Appliance Database.
• 2026-06-09 — researched as variant of fixed habit appliance

category; cross-referenced to Tongue crib.