| Field | Value |
|---|---|
| ID | OA-0330 |
| Type | distalizer |
| Category | distalizer |
| Fixed/removable | removable |
| Primary function | maxillary molar distalization (+ bite opening) |
| Malocclusion target | Class II with deep bite; mild molar Class II |
| Inventor | Haas (original ACCO) |
| First year | 1970s |
| Period | historical / current |
| Status | current |
| Treatment effect | primarily molar tipping (~1 mm/month); some bite opening |
| Uses TADs | no |
The ACCO (Acrylic Cervical Occipital) appliance is a removable acrylic plate designed to distalize upper molars using cervical headgear force. It features Adams clasps on the upper first molars for retention, a labial arch for anterior tooth contact, an acrylic palatal body, an anterior bite plate for bite opening, and posterior hooks or tubes that accept the headgear face bow. When worn with cervical headgear for the prescribed hours (typically 12–14 hours/day), the combined force distalizes and tips the upper molars distally at approximately 1 mm/month. It is one of the older compliance-dependent distalizers still in use, valued for its simplicity of fabrication and the combined benefits of distalization plus bite opening.
The cervical headgear delivers a posteroinferior force via the face bow, which is transferred through the acrylic appliance and Adams clasps to the upper molars, tipping and translating them distally. The anterior bite plate opens the bite by preventing posterior occlusion during wear — over time this produces some genuine bite opening through vertical eruption of the posterior teeth and inhibition of anterior eruption. The effect is primarily molar tipping (not bodily movement). Average distalization: ~1 mm/month with consistent wear. Class II correction typically takes 6–12+ months depending on compliance.
Class II malocclusion with deep bite component; growing patients (ages 8–13) where compliance for headgear is expected; mild Class II correction (2–4 mm) that doesn't warrant a fixed distalizer; cases where bite opening is also a treatment goal; practices that use cervical headgear as part of their phase I protocol; patients and parents who accept removable appliance management. The ACCO is most effective in the mixed dentition or early permanent dentition in growing patients.
Entirely compliance-dependent — results are directly proportional to wear time. Produces molar tipping (not bodily movement), which must be corrected during subsequent fixed braces treatment. Bite opening effect may not be desirable in high-angle (hyperdivergent) patients. Headgear use in orthodontics has declined significantly in contemporary practice due to compliance challenges and safety concerns — the ACCO represents an older treatment paradigm. Modern practices more commonly use fixed distalizers (Pendulum, Distal Jet) or TAD-supported distalization instead.
clasp-fits)
the face bow
Adams clasp fit on the molars must be tight — the headgear delivers significant force and loose clasps cause the appliance to dislodge. The anterior bite plate must cover the upper incisors' incisal edges sufficiently to prevent posterior occlusion during wear. Acrylic must be uniformly thick (3–4 mm minimum) to resist fracture under headgear forces. Cervical hooks must be soldered securely and positioned to accept standard J-hook headgear or face bow. CFL prices the ACCO at (standard) and (variant or updated version) — among the most affordable distalizers due to its simple construction.
bite plate.
.
version.
— fixed distalizer; no compliance required.
bodily-movement-focused distalizer.
Lab](https://www.ddslab.com/orthodontics/distalization/acco/)
PMC](https://pmc.ncbi.nlm.nih.gov/articles/PMC8185153/)
Review](https://orthodonticreview.com/removable-distalizers/)
fabrication, business notes.