Complex Invisalign Dublin: When a Specialist Orthodontist Matters

Q: How much does complex Invisalign cost at ISCD?

A specialist orthodontic assessment at ISCD is 150 euro and Invisalign starts from 2,500 euro per case. Complex cases are quoted in writing after assessment, because the fee depends on the treatment plan, including the number of aligners, refinements and any auxiliary mechanics.

Last reviewed: September 2026

Clear aligners are now offered widely, and for straightforward crowding and spacing they work well. The difficulty is that the word “Invisalign” describes an appliance, not a case. The same trays that close a small gap predictably can struggle with a rotated canine, an extraction space or a deep bite — and whether a given case falls on one side of that line or the other is a diagnostic question, not a marketing one. At the Institute of Specialist and Cosmetic Dentistry (ISCD) in Dublin’s IFSC, clear aligner treatment is planned and supervised by our specialist orthodontists. This guide sets out what the published evidence says about aligners in complex cases, where a specialist changes the outcome, and when we advise a different appliance altogether — for patients weighing up treatment and for referring dentists deciding where a case belongs.

What makes an Invisalign case “complex”?

An aligner case is complex when it depends on movements aligners deliver less predictably, such as bodily root movement, extrusion, rotation of rounded teeth, extraction space closure or larger bite corrections.

Complexity is not the same as how crooked the teeth look. A patient with visibly crowded front teeth may need little more than levelling and alignment, which aligners do well. A patient whose teeth look almost straight may need a deep bite opened, a canine derotated or a molar relationship corrected, and those are the movements the evidence identifies as harder to achieve with a removable tray.

In practice, the cases we treat as complex fall into a handful of groups: moderate to severe crowding where teeth must be extracted to create space; deep bites and open bites; Class II and Class III molar relationships; significantly rotated premolars and canines; cases where periodontal support or existing restorations limit how teeth can be moved; and adult cases where a previous course of aligners has stalled. Dental crowding on its own is covered in our guide to Invisalign for crowding; this article is about the cases beyond it.

What can clear aligners do predictably, and where are they weaker?

Systematic reviews consistently find that aligners level, tip and align teeth reliably in mild to moderate non-extraction cases, and are less effective for extrusion, rotation of rounded teeth, bodily expansion and closing extraction spaces.

Papadimitriou and colleagues, in a systematic review published in Progress in Orthodontics in 2018, included three randomised controlled trials, eight prospective and eleven retrospective studies of the Invisalign system. The heterogeneity between studies was too high to pool the results, but the authors found substantial consistency that Invisalign is a viable alternative to conventional treatment for mild to moderate malocclusions in non-growing patients who do not need extractions, and that the aligners can predictably level, tip and derotate teeth — except canines and premolars. They identified limited efficacy in arch expansion through bodily tooth movement, extraction space closure, correction of occlusal contacts, and larger antero-posterior and vertical discrepancies.

An earlier systematic review by Rossini and colleagues in The Angle Orthodontist (2015), based on eleven studies, reached a similar shape of conclusion from a different direction. Extrusion was the most difficult movement to control, at 30% accuracy, followed by rotation, and aligners were not effective in controlling rotation of rounded teeth in particular. Upper molar distalisation, by contrast, showed the highest predictability — 88% — when a bodily movement of at least 1.5 mm was prescribed. The authors asked for their results to be interpreted with caution, given the number, quality and heterogeneity of the studies.

In plain terms: the movements aligners handle well are the ones most straightforward cases need. The movements they handle less well are precisely the ones that make a case complex. That is why appliance selection is a clinical decision rather than a preference.

How closely does the finished result match the digital plan?

Prospective measurement found that teeth achieve on average around half the movement prescribed in the digital plan, which is why complex aligner cases need planned overcorrection and refinement aligners.

Every aligner case begins with a digital simulation showing the teeth moving into their final position. It is a persuasive image, and it is a plan rather than a prediction. Haouili and colleagues, in a prospective study published in the American Journal of Orthodontics and Dentofacial Orthopedics in 2020, measured 38 patients by superimposing the planned final position on scans taken after treatment. The mean accuracy for all tooth movements was 50%. The highest accuracy was for buccal-lingual crown tip (56%) and the lowest for rotation (46%), with particularly low figures for mesial rotation of the lower first molar (28%), distal rotation of the upper canine (37%) and intrusion of the lower incisors (35%). The authors noted a marked improvement over earlier generations of the system, but that its strengths and weaknesses had remained relatively the same.

A 2026 scoping review by Borzabadi-Farahani in Frontiers in Dental Medicine, mapping 119 studies, reported that — based on the limited studies available — refinements were required in over 50% of cases and 17.2% needed conversion to fixed appliances. The author is clear that most of that evidence is retrospective and Invisalign-focused, and should not be treated as a universal benchmark. The practical conclusion, though, is stated directly: for complex malocclusions, hybrid approaches and informed consent about possible conversion to fixed appliances are advisable.

We take that conclusion at face value. A patient starting a complex aligner case at ISCD is told before treatment begins that refinement aligners are an expected part of the process rather than a sign that something has gone wrong, and that there are cases in which a short phase of fixed mechanics is the most efficient way to finish.

Can extraction cases be treated with aligners?

Extraction cases can be treated with aligners, but pooled evidence shows less precise root control, under-retraction of the front teeth and more molar tipping than planned, so they demand specialist planning and often auxiliary mechanics.

Closing the space left by an extracted premolar is one of the most demanding things an orthodontic appliance is asked to do: the neighbouring teeth have to move bodily, roots and all, rather than simply tip into the gap. Abu Arqub and colleagues, in a systematic review and meta-analysis published in Orthodontics & Craniofacial Research in 2026, pooled 20 studies covering 536 aligner patients and 173 fixed-appliance patients. They found significant discrepancies between predicted and achieved movement, including excessive mesial tipping of the upper first molars (mean difference −6.08°) and under-retraction of the upper incisors (−1.93 mm). Root divergence and anchorage loss were common, and compared with fixed appliances, aligners showed inferior root control and occlusal contact scores. The authors conclude that extraction cases need strategic overcorrection and adjunctive mechanics.

A small randomised controlled trial by Jaber and colleagues (International Orthodontics, 2023) is worth reporting alongside it, because its result is more nuanced than either side of the argument tends to admit. Forty young adults with severe crowding requiring four premolar extractions were randomised to aligners or fixed braces and scored on the American Board of Orthodontics Objective Grading System. The difference in total score was not statistically significant, and occlusal contacts were significantly better with fixed appliances. But 17 of 20 fixed-appliance cases achieved a passing score against 11 of 20 aligner cases — a gap the authors themselves say must be considered clinically when choosing an appliance for complex cases, even though it did not reach statistical significance in a trial of this size.

Are aligners as good as fixed braces for complex cases?

For non-extraction cases, current meta-analysis finds no significant difference in treatment quality between aligners and fixed braces; in extraction cases, fixed appliances provided superior treatment quality, attributed to better control of tooth movement.

The most recent pooled comparison is a systematic review and meta-analysis by Alhafi and colleagues in the European Journal of Orthodontics (2025), which included 15 trials involving 1,084 patients. In non-extraction cases, treatment quality and duration did not differ significantly between the two approaches. In extraction cases, fixed appliances produced superior treatment quality. Limited evidence suggested similar stability after treatment, though short follow-up and heterogeneity between studies limited how firmly that could be concluded.

The authors’ closing sentence is the one we would put in front of any patient choosing between appliances: case complexity and patient compliance should guide appliance selection. It is also the reason we are wary of “Invisalign or braces?” being framed as a lifestyle choice. For many cases it genuinely is one. For some, it is a decision about which appliance can deliver the result — and our comparison of Invisalign and fixed braces sets out where each has the advantage.

What does a specialist orthodontist change in a complex aligner case?

A specialist changes the diagnosis and the plan: identifying movements aligners will under-deliver, designing overcorrection and attachments to compensate, and deciding in advance when auxiliaries or fixed mechanics are needed.

The aligners themselves are manufactured from the digital plan, and the plan is only as good as the diagnosis beneath it. In a complex case, that diagnosis draws on full orthodontic records — clinical examination, photographs, intraoral scans and radiographs, with cephalometric analysis of the skeletal pattern where the bite is involved — so that the treatment objective is set by the underlying problem rather than by what the software can animate.

From there, the specialist’s work is largely about anticipating the gap between planned and achieved movement that the studies above describe. That means prescribing overcorrection for movements known to lag, choosing attachment designs for the teeth that need more grip, sequencing movements so that difficult ones are not attempted all at once, and monitoring tracking closely enough to catch a tooth falling behind before the next set of aligners compounds the problem. Where the evidence says aligners alone will not be efficient, it means planning auxiliaries from the outset — elastics, sectional fixed mechanics, or skeletal anchorage with temporary anchorage devices (TADs), which our orthodontic service provides.

Just as important is the case that is not started. Part of a specialist assessment is saying plainly when a patient would be better served by fixed ceramic or metal braces or by customised lingual braces, which are fitted to the inside surfaces of the teeth and give fixed-appliance control without visible brackets. A patient who wants an invisible appliance for a case aligners handle poorly has more than one discreet option, and should hear about all of them.

When would a specialist recommend a different appliance instead?

Fixed or lingual appliances are usually preferable where a case depends on precise root control, significant extrusion, large bite correction or extraction space closure, or where daily aligner wear is unrealistic.

There is no single rule, and many cases sit in the middle, where either approach is clinically reasonable and the patient’s preferences rightly decide. But the evidence points in a consistent direction for a recognisable group of cases: extraction treatment where the roots of the teeth either side of the space must be moved bodily; teeth that need to be extruded; heavily rotated canines and premolars; larger antero-posterior and vertical discrepancies; and cases where precise final occlusal contacts matter for function or for a planned restorative phase.

Compliance is the other deciding factor, and it is not a judgement of character. Aligners only work while they are worn. A patient whose work, sport or daily routine makes consistent wear unrealistic will usually get a better result from an appliance that cannot be taken out. Where the underlying problem is skeletal rather than dental — a jaw discrepancy no appliance can correct — the conversation moves on to combined orthodontic and surgical treatment, which we co-ordinate with a maxillofacial surgical team.

What does the European Board of Aligner Orthodontics Diplomate mean?

Diplomate status of the European Board of Aligner Orthodontics is a peer-examined certification: candidates present completed aligner cases, with follow-up records at least a year after treatment, and pass an oral examination on them.

Most aligner qualifications a patient will come across are provider tiers or training certificates, which reflect courses attended or the number of cases started. Board certification is different in kind. According to the Board’s own published guidelines, candidates on the route for experienced clinicians must have practised independently in orthodontics for at least five years, and must present a minimum of five completed aligner treatments drawn from set case categories — including interdisciplinary cases with surgical, restorative or periodontal involvement — each treated with aligners for at least 80% of the treatment time. Every case must include records at the start and end of treatment and follow-up records taken at least twelve months after treatment has finished. The candidate then discusses the diagnosis, planning and outcome of each case at an oral examination, and the examination is conducted anonymously.

The twelve-month follow-up requirement is the part worth noticing. It means the certification assesses whether a result held, not only how it looked on the day the aligners came out.

Dr Erfan Salloum is a Diplomate of the European Board of Aligner Orthodontics and of the European Board of Orthodontics, and a Titular Member of the European Society of Lingual Orthodontics. He is one of a small number of orthodontists in Ireland to hold European distinctions across the three major fields of contemporary orthodontics — comprehensive, clear aligner and lingual — which matters in complex cases because the right answer is not always an aligner. Clear aligner treatment at ISCD is provided by our two specialist orthodontists, Dr Salloum and Dr Susan O’Connell, whose Invisalign service is described separately.

What happens if aligner treatment elsewhere has stalled?

A stalled aligner case is often retrievable: a specialist re-records the teeth, identifies which movements have not tracked, and re-plans with refinements, auxiliaries or a short fixed phase.

It is a common referral, and an entirely understandable one. A patient reaches the end of a set of aligners and the teeth are not where the simulation showed — often because a rotation, an extrusion or a bite correction has lagged, which is exactly the pattern the accuracy studies predict. Continuing to wear later aligners in the original sequence rarely fixes that, because each subsequent tray assumes the earlier movements were achieved.

The first step is a fresh diagnosis rather than a new set of trays: new records, an assessment of which teeth have tracked and which have not, and an honest view of whether aligners remain the right appliance. Sometimes a refinement plan with changed attachments completes the case. Sometimes a brief phase of fixed or lingual mechanics finishes the movements aligners could not, after which the patient can return to aligners or retainers. For referring dentists, these cases are better sent early than late — the longer a tooth tracks off-plan, the more there is to recover.

What does complex Invisalign treatment cost at ISCD, and how do dentists refer?

A specialist orthodontic assessment at ISCD is €150, and Invisalign treatment ranges from €2,500 to €3,500 per case; complex cases are quoted in writing after assessment, because the plan determines the fee.

Our published orthodontic fees are a specialist orthodontic assessment at €150, Invisalign at €2,500 to €3,500 per case, fixed metal or ceramic braces at €1,250 to €3,500 per arch, and interceptive treatment for children from €600. For a complex aligner case, the fee depends on the length and complexity of the treatment plan, including the number of aligners, planned refinements and any auxiliary mechanics, so we do not quote a figure over the phone. Following the assessment, you receive a detailed written treatment plan and cost breakdown before any commitment is made. Our guide to Invisalign costs explains how orthodontic fees are structured more generally.

We do not discount orthodontic treatment and we do not offer free consultations. The assessment is a clinical appointment with a registered specialist, and the diagnosis made there is what the rest of the treatment depends on.

For referring dentists: ISCD accepts direct orthodontic referrals, and the referring practice keeps the patient for routine and restorative care throughout. Complex aligner cases — extraction cases, bite corrections, ortho-restorative planning, and aligner treatment that has stopped tracking — are welcome as assessment referrals, and we welcome a phone call to discuss a case before referral. Our referral process for Dublin dentists sets out what to send.

Frequently asked questions about complex Invisalign in Dublin

Can Invisalign treat complex cases?
Some, with specialist planning. Systematic reviews find aligners reliable for mild to moderate non-extraction cases and less effective for extrusion, rotation of rounded teeth, bodily expansion and extraction space closure. Complex aligner cases usually need overcorrection, refinement aligners and sometimes auxiliary mechanics, and some are better treated with fixed or lingual braces.

Will I need refinement aligners?
In complex cases, often yes. A prospective study by Haouili and colleagues (2020) found that teeth achieved on average 50% of the movement prescribed in the digital plan, and a 2026 scoping review reported refinements in over 50% of cases in the limited studies available. We explain this before treatment starts so that refinements are expected rather than a surprise.

Are fixed braces better than aligners for extraction cases?
The pooled evidence favours fixed appliances for extraction cases. A 2025 meta-analysis of 15 trials and 1,084 patients by Alhafi and colleagues found no significant difference in treatment quality for non-extraction cases, but superior treatment quality with fixed appliances in extraction cases, attributed to better control of tooth movement.

How much does complex Invisalign cost at ISCD?
A specialist orthodontic assessment at ISCD is €150 and Invisalign ranges from €2,500 to €3,500 per case. Complex cases are quoted in writing after assessment, because the fee depends on the treatment plan, including the number of aligners, refinements and any auxiliary mechanics.

Arranging an assessment

If you have been told your case is too complex for aligners, if aligner treatment elsewhere has stopped tracking, or if you are a dentist with a patient whose case needs more than straightforward alignment, a specialist orthodontic assessment is the place to start. We will tell you which appliance can deliver the result, and why.

Institute of Specialist and Cosmetic Dentistry (ISCD)
4 NCI, Lower Mayor Street, IFSC, Dublin, D01 R7W7
Telephone: +353 1 504 2065
Email: info@iscd.ie

Written by Dr. Erfan Salloum, BDS, PGCert(Orth), DClinDent(Orth), MsLing(Orth), MFD RCSI, MFDS RCPSG, MOrth RCSEd, FFD(Orth) RCSI, MOrth RCSEng, FDS RCSEng, FDS RCPSG — Specialist Orthodontist at the Institute of Specialist and Cosmetic Dentistry, Dublin. Diplomate of the European Board of Aligner Orthodontics.

References

Papadimitriou A, Mousoulea S, Gkantidis N, Kloukos D. Clinical effectiveness of Invisalign® orthodontic treatment: a systematic review. Progress in Orthodontics. 2018;19(1):37. doi:10.1186/s40510-018-0235-z
Rossini G, Parrini S, Castroflorio T, Deregibus A, Debernardi CL. Efficacy of clear aligners in controlling orthodontic tooth movement: a systematic review. The Angle Orthodontist. 2015;85(5):881–889. doi:10.2319/061614-436.1
Haouili N, Kravitz ND, Vaid NR, Ferguson DJ, Makki L. Has Invisalign improved? A prospective follow-up study on the efficacy of tooth movement with Invisalign. American Journal of Orthodontics and Dentofacial Orthopedics. 2020;158(3):420–425. doi:10.1016/j.ajodo.2019.12.015
Borzabadi-Farahani A. Clear aligner therapy: a scoping review of treatment prediction, clinical effectiveness, and limitations. Frontiers in Dental Medicine. 2026;7:1864529. doi:10.3389/fdmed.2026.1864529
Abu Arqub S, Chheda H, Crumpton J, Yang X, Farha P, Upadhyay M. Clear aligners in extraction-based orthodontic treatment: a systematic review and meta-analysis. Orthodontics & Craniofacial Research. 2026;29(1):12–29. doi:10.1111/ocr.70052
Jaber ST, Hajeer MY, Burhan AS, Alam MK, Al-Ibrahim HM. Treatment effectiveness of young adults using clear aligners versus buccal fixed appliances in class I malocclusion with first premolar extraction using the ABO-Objective Grading System: a randomized controlled clinical trial. International Orthodontics. 2023;21(4):100817. doi:10.1016/j.ortho.2023.100817
Alhafi ZM, Hajeer MY, Alam MK, Jaber ST. Quality and stability of orthodontic treatment outcomes with clear aligners versus fixed appliances: a systematic review and meta-analysis. European Journal of Orthodontics. 2025;47(6):cjaf091. doi:10.1093/ejo/cjaf091
European Aligner Society. The European Board of Aligner Orthodontics: Guidelines. EAS Committee.