| Field | Value |
|---|---|
| ID | OA-0332 |
| Type | distalizer |
| Category | distalizer |
| Fixed/removable | fixed |
| Primary function | simultaneous maxillary molar distalization + transverse expansion |
| Malocclusion target | Class II with transverse maxillary deficiency |
| Inventor | Hilgers (Pendex = Pendulum + Expansion) |
| First year | 1994 |
| Period | modern |
| Status | current |
| Spring material | 0.032″ TMA cantilever springs |
| Expansion component | midline jackscrew (RPE-type) |
| Uses TADs | no |
The Pendex (Hilgers, 1994) combines the Pendulum distalizer with a midline expansion screw in a single palatal appliance. The TMA cantilever springs distalize the upper molars while the jackscrew simultaneously expands the maxilla — both movements happen concurrently, reducing total treatment time compared to sequential (expand first, then distalize) staging. This is its primary clinical advantage: treating two dimensions of Class II + narrow arch simultaneously. The appliance is fabricated with the Pendulum spring mechanism integrated into a palatal body that also houses a midline expansion screw.
The TMA springs (as in the standard Pendulum, Pendulum appliance) deliver 200–250 g distal force to each upper molar while the midline jackscrew is activated to open the mid-palatal suture. The simultaneous activation protocol means the clinician (or parent) turns the screw on the same schedule as the springs are delivering distalization force. Practical effect: the molars move distally while the arch widens, preparing the upper arch comprehensively for subsequent fixed braces. The simultaneous movement may slightly reduce each individual force because the arch is also widening, but the net treatment time savings versus sequential treatment is documented.
Class II malocclusion combined with maxillary transverse deficiency (the common combined presentation); growing patients where both problems must be addressed; cases where the clinician wants to treat both dimensions simultaneously rather than sequentially; non-extraction treatment where arch length gain (from expansion) + Class II correction (from distalization) together eliminate the space deficit. The ideal Pendex patient has clear Class II molar relationship AND a documented posterior crossbite or constricted maxillary arch.
More complex than either the Pendulum or RPE alone — both spring activation and screw turning must be coordinated. More palatal bulk than a single-function appliance. Slight loss of individual appliance efficiency (each component partially works against the other's anchorage). Not appropriate if only distalization or only expansion is needed — the pure Pendulum or RPE is better in those cases. Requires detailed patient/parent instruction for dual activation.
Pendulum
housing and the spring activation slots
adjustment
Fabrication is the most complex of the distalizer series — both the spring arms and the midline screw must be precisely placed and co-located in the acrylic body without interfering with each other. The acrylic body must be substantial to house the screw hardware without fracture. The springs must be embedded such that their activation slots are accessible chairside for adjustment. CFL prices the Pendex — above the standard Pendulum, representing the added complexity. This is a reasonable premium that should cover the additional lab time without pricing the appliance out of range.
— distalization only; no expansion screw.
expansion only; no distalizer springs.
anchorage; eliminates all dentoalveolar anchorage loss.
Ortho](https://fivestarortho.com/appliances/distalization/pendex/)
Lab](https://www.ddslab.com/orthodontics/distalization/pendex/)
PMC 2021](https://pmc.ncbi.nlm.nih.gov/articles/PMC8185153/)
fabrication, business notes.