A piece of transparent plastic moves teeth through solid bone. That sounds impossible until you see the mechanism — and understanding it will make you a far better patient.
An iTero scanner sweeps your teeth with structured light, capturing tens of thousands of measurement points per second and building a sub-millimetre-accurate digital model — no goo, no gagging, about ten minutes. This model is the raw material everything else is computed from, which is why it's the anchor of your one records trip to New Delhi.
Orthodontic planning software (ClinCheck, for Invisalign) lets your orthodontist choreograph each tooth's path — what rotates, what tips, what moves bodily, in which order, at what speed. Teeth can't all move at once like a marching band; good plans sequence movements the way a puzzle is solved. You review the final animation — your projected smile — before paying. This is also the moment an honest provider tells you if your case needs braces instead (who's a candidate).
Teeth sit in sockets cushioned by the periodontal ligament. Sustained gentle pressure triggers two cell types: osteoclasts dissolve bone on the side the tooth is moving toward; osteoblasts lay down new bone in the space left behind. The tooth doesn't punch through bone — the bone remodels around the moving tooth. Each aligner stage exploits this with ~0.25mm of programmed movement over 1–2 weeks; multiply by 20–50 stages and you get a transformed smile. It's also why 22-hour wear is non-negotiable: remodelling is a sustained process, not an event.
Can: crowding, spacing, rotations, most overbites and crossbites, relapse after braces — the six patterns on our candidate page. Can't: move the jawbone itself (skeletal discrepancies), erupt impacted teeth, or replace surgical care. Physics and biology set the limits; marketing doesn't get a vote — and a provider who explains the limits is the one to trust (the vetting checklist).
Notice what the process needs from a clinic: one excellent scan, one expert plan, one fitting — then biology does the work wherever you live, with photographic check-ins confirming teeth are tracking the plan. That's the entire reason treatment in India at a third of the price works for international patients without compromise.
Each aligner is manufactured slightly ahead of your current tooth positions — by about 0.25mm per stage. Wearing it presses teeth toward that target; the pressure signals bone cells to resorb bone on the pressure side and build it on the tension side, letting the tooth migrate. Twenty to fifty small steps later, teeth arrive where the digital plan placed them.
Tooth-coloured composite shapes bonded temporarily to certain teeth. Smooth plastic can't grip a smooth tooth well enough for rotations or vertical movements — attachments act as handles that let the aligner push and pull with precision. They're polished off completely at the end of treatment.
Bone remodelling needs sustained pressure. Interrupt it too long and the biological process stalls — the tooth drifts back toward its old position and the next tray no longer fits accurately. The 2–4 hours out is budgeted for meals and brushing; discipline beyond that is genuinely the difference between on-schedule and stalled treatment.
Expect pressure, not pain: the first day or two of each new tray feels snug and tender — that's the biology working. Most people describe it as far milder than braces adjustments, and it fades as the teeth catch up to the tray.
Free assessment — and if you proceed, you watch your projected result on screen before paying.