Invisalign Lateral Incisor Case Study

Front view of a smile after four months of clear aligner treatment, with the lateral incisors aligned in the arch. Individual results vary.

A three-to-four-month clinically document Invisalign case from Sunny Dental Centre, Guelph - Fixing a crooked tooth

The short version. An upper lateral incisor that sat behind the arch and kept chipping. Rather than repairing it a third time, we moved it into position with clear aligners and rebalanced the bite first, so the chipped edge could then be handled with polishing and a small repair instead of a crown. Active treatment ran three to four months, followed by retention. The full case study, month by month, is below.

Note the images and content below are content from a real clinic case and images with patient consent and written by Dr. Puri. The goal is to provide in-depth clinical cases for educational purposes by Sunny Dental Centre, this content is property of Dr. Puri and Sunny Dental Centre.

Why does the same front tooth keep chipping?

When a patient tells us one particular tooth keeps breaking, the tooth itself is rarely the whole story. Teeth are built to share force. When one tooth sits out of line; tucked behind its neighbours, rotated, or catching the bite at the wrong angle, it can end up taking force it was never meant to absorb. You can repair that tooth as many times as you like; until the position and the bite change, the repairs can keep failing.

This case study follows one such tooth: an upper lateral incisor that sat toward the palate, had chipped repeatedly, and had been bonded and re-bonded over the years. Rather than restoring it again; or removing tooth for a crown we repositioned it first with Invisalign clear aligners and rebalanced the bite, so that in the end only conservative small repair and polishing were needed.

Close-up smile before Invisalign treatment showing the upper lateral incisors sitting behind the line of the arch. — Figure 1 (Modified image): The starting point. Both upper lateral incisors sit behind the line of the arch — tipped in toward the palate. Individual results vary. Note this image has been generatively updated, the initial photo had been heavily blurred.

The concern

The patient came to us about an upper lateral incisor, one of the smaller teeth on either side of the two front teeth. It sat noticeably toward the palate, was rotated, and was constantly chipping. In fact, both of the upper lateral incisors sat behind the line of the arch, with one more severely affected. He had a history of clenching and grinding (bruxism), and the chipping tooth had previously been bonded and repaired more than three times.

His orthodontic history mattered too. Years earlier he had subscribed to a mail-order aligner company. That company later ceased operations, and he was left partway through treatment with no results, no follow-up, and no retainers. The movement he had achieved regressed once the trays stopped.

That history told us two useful things. First, his teeth had responded to aligner treatment before, which was encouraging. Second, it was a clear demonstration of something we tell every orthodontic patient: teeth have a natural tendency to move, and retention is a lifetime commitment. Movement without retention can be temporary.

Occlusal view of the upper arch before treatment, with the lateral incisors displaced toward the palate. — Figure 2 (modified image): Occlusal (biting-surface) view of the upper arch before treatment. The chief complaint was the lateral incisors, but the premolars also show slight rotation and misalignment.

The assessment

Every case starts with a clinical assessment aimed at the source of the complaint, not just the damage. The exam confirmed a history of bruxism and clenching, and repeated chipping of a tooth that had previously been bonded and restored. Assessment of the bite revealed minimal overjet (limited front-to-back clearance between the upper and lower front teeth) and positional interferences on lateral excursions — meaning the malpositioned tooth was catching force when the jaw slid side to side.

The problem list:

Reduced overjet and misalignment of the upper front teeth
Under-eruption of one lateral incisor (it had not fully erupted to the height of its neighbours)
Mesial rotation (rotation toward the midline) and lingual positioning of both upper lateral incisors
Repeated chipping of a previously restored lateral incisor, with bruxism as a contributing habit
premolar reotation

Diagnosis: malocclusion, with a history of tooth fracture.

The options and why we aligned first

We discussed the realistic options: no treatment, restorative repair alone (bonding again, or a ceramic crown), or orthodontic repositioning first, followed by restorative work as appropriate.

Repositioning first was our recommendation, for one central reason: a restoration placed on a tooth that is still taking interference tends to fail the same way the tooth did. Aligning the tooth and balancing the bite first meant that afterwards there would be no interferences loading that one tooth; neither when the jaw slides side to side (lateral excursions) nor when the front teeth guide it forward (anterior guidance). At that point, a future restoration would be protected and in this case, we anticipated that crown coverage would likely not be needed at all. A more conservative option, such as polishing and a small filling, could do the job. That is the difference between treating the chip and treating the reason for the chip.

The patient chose orthodontic treatment with clear aligners (Invisalign), which also allowed additional alignment improvements to be made during the same treatment.

The plan: a digital workup

Every aligner and invisalign case requires a comprehensive workup. We took a full digital scan with an intraoral scanner (iTero) and completed a three-dimensional treatment plan using ClinCheck, Invisalign's planning software. The software stages the movements; which teeth move at each step, which serve as anchors and predicts where interproximal reduction (IPR) or attachments will be needed. The clinician then reviews and modifies that plan before trays are ordered.

One honest note about digital previews, because patients often ask: the 3D preview is a plan, not a promise. Independent reviews of aligner treatment find that most tooth movements are not predictable enough to finish with a single series of trays, refinement scans and additional tray series are a normal, planned part of how this treatment works, not a sign that something went wrong [2,3].

iTero intraoral scanner displaying a three-dimensional digital model of the dental arch. — Figure 3: The iTero intraoral scanner used for the digital workup. The scan replaces conventional impressions and lets the movements be staged in three dimensions before any trays are made.

Diagram of the diagnostic findings, problem list and projected month-by-month clear aligner plan. — Figure 4: The diagnostic findings and problem list, with the projected month-by-month plan for the case.

The treatment

First appointment: interproximal reduction (IPR)

The plan called for IPR at a few contact points along the lateral incisors. Between 0.1 mm to 0.2 mm per contact. IPR removes a measured fraction of a millimetre of enamel between two teeth using a fine abrasive strip or tool, after which the surface is polished and the contact is verified. This small amount of space is enough to let the tooth move unimpeded, with minimal removal of tooth structure.

Is filing between teeth safe? IPR has been used and studied for decades, and follow-up studies have not found increased decay or gum disease in treated teeth [8] — though it is worth knowing those studies are older and small, which is why we keep IPR to the minimum the plan requires, polish the surfaces afterwards, and chart every site.

Diagram of interproximal reduction: removing a fraction of a millimetre of enamel at a contact point, then polishing. — Figure 5: Interproximal reduction: a calibrated strip removes 0.1–0.2 mm of enamel at a planned contact point, which is then polished and charted.

Attachments — the “buttons”

Composite attachments (often called buttons) were placed on the lateral incisors. These are small bumps of ordinary tooth-coloured filling material bonded temporarily to the tooth surface. They work like handles or door knobs: they give the tray something to grip so it can push and rotate the tooth. This matters especially for small, rounded teeth like lateral incisors, which the plastic otherwise grips poorly. Placing attachments requires no drilling and no anesthetic, and they are removed and polished off at the end of treatment.

At this stage we also noted an existing composite restoration on the upper left central incisor that was beginning to lift at its margin. It was monitored through treatment and addressed at the finishing stage.

Diagram of composite attachment placement on the teeth using a template tray. — Figure 6: How composite attachments are placed: a template positions each attachment, composite is bonded to the enamel and shaped, then polished off at the end of treatment. The process is additive only, with no drilling.

Trays and instructions

The patient was provided four weeks of trays at a time, each tray worn for about a week, with a follow-up roughly every month. Instructions were simple:

Wear the trays all day and night, removing them only to eat and for cleaning. Aligners only work while they are on your teeth (about 22 hours a day).
Change to the next tray on the schedule provided. If it does not fit, keep wearing your current tray for another week. If it still doesn't - contact the dentist.
Use chews constantly to ensure the trays are always seated fully.
Keep up daily brushing and flossing, with hygiene visits on the recall schedule set for you. Clean your trays daily.
Inspect regularly for fractured or worn down buttons.

What we check at every follow-up

At each visit, before the next set of trays was issued, we confirmed that the current trays were seating fully on every tooth, that all attachments were intact and engaging the trays, that the gums showed no localized inflammation and oral hygiene was being maintained, that tooth mobility was within normal limits, and that the planned IPR contacts remained free so movement could continue. If a tray is not fully seating, issuing the next one anyway is how aligner treatment quietly goes off track; the fix is to slow down, not push forward and understand why. Note: In some cases, certain brackets may be removed or added at different phases of treatment and elastics used.

Diagram of the items checked at each monthly clear aligner follow-up visit. — Figure 7: What is assessed at each monthly review: full tray seating, attachment integrity, gum health and hygiene, tooth mobility, and the planned IPR contacts.

The time-lapse: three to four months of movement

Individual results vary. The images below show this patient's treatment; what is achievable in any case depends on the teeth, the bite and the goals.

Active treatment in this case ran between three and four months. That figure excludes the retention phase, which, as we cover below, is in this casefull time use for 3 months and then nightly.

Month 1 : Movement Begins

By the first follow-up, the lateral incisors were displaying buccal movement (tipping outward toward the arch line). The central incisors were inclining lingually (tipping slightly inward) as programmed, the premolars were showing early signs of rotating into better position, and the arch form was beginning to improve. The visual change in position was already clear.

Side view of the smile at one month of clear aligner treatment showing early movement of the lateral incisor. — Figure 8 (real patient image): Month 1, side view: early movement of the lateral incisor toward the arch line.

Front view of the smile at one month of clear aligner treatment. — Figure 9 (real patient image): Month 1, front view.

Occlusal view of the upper arch at one month of aligner treatment with composite attachments in place. — Figure 10 (real patient image): Month 1, occlusal view - the lateral incisors have begun moving outward and the arch form is starting to round out. The composite attachments are visible on several teeth.

Month 2: Movements progressing

Movement continued as planned. It is worth saying that lateral incisors can be difficult teeth to move; they are small and rounded, and rotation of small, rounded teeth is among the less predictable aligner movements [3]. This is exactly why the attachments were placed. Gradual, steady movement was visible at each visit, the trays were engaging fully, all attachments were intact, and gum health and hygiene were well maintained.

Side view of the smile at two months of clear aligner treatment. — Figure 11 (real patient image): Month 2, side view - the lateral incisor continues to rotate and tip into position.

Front view of the smile at two months of clear aligner treatment. — Figure 12 (real patient image): Month 2, front view - the lateral incisors continue to move toward the line of the arch.

Occlusal view of the upper arch at two months of aligner treatment showing progressive alignment. — Figure 13 (real patient image): Month 2, occlusal view. Compare the lateral incisor position and premolar rotation against the initial occlusal view above.

Month 3: the final month of trays

The remaining trays in the series were completed. Completing the trays, however, does not mean treatment is finished, this is the point where we re-evaluate against the original goals: Did the tooth reach its planned position? Is the bite balanced? Are there interferences left when the jaw slides?

Front view of the smile in the final month of aligner treatment with the lateral incisors aligned. — Figure 14 (real patient image): Month 3, front view — the final month of the tray series. The lateral incisors now sit within the arch line.

Side view of the smile in the final month of clear aligner treatment. — Figure 15 (real patient image): Month 3, side view, before attachment removal and finishing.

The result

At re-evaluation, the primary goals had been achieved: the lateral incisors were aligned within the arch, and checking the bite confirmed no remaining interferences concentrated on the repositioned tooth — in side-to-side movements or in the way the front teeth guide the jaw.

Finishing then proceeded conservatively, in this order:

The attachments were removed and the teeth polished.
The chipped edges of the lateral incisor were addressed. First smoothed and repaired, rather than crowned. With the interferences eliminated, conservative treatment was appropriate, and crown coverage was not needed.
The leaking composite restoration on the central incisor was repaired and polished.
A removable retainer was provided, with a three-month full-time retention protocol; after that, the retainer is worn nightly.

Diagram of end-of-treatment finishing: composite attachment removal, polishing and retention. — Figure 16L End-of-treatment finishing: the composite attachments are removed and polished off, the chipped edge is repaired, and the retention phase begins.

Figure 17 (real patient image): Final result, profile view, after completion of orthodontic treatment, polishing and repair of the chipped edges. Individual results vary.

Front view of the final smile after three to four months of aligner treatment showing aligned upper lateral incisors. — Figure 18 (real patient image): Final result, front view. The lateral incisors sit in the arch, the bite has been balanced, and the previously chipping tooth was finished with polishing and a small repair rather than a crown. A removable retainer maintains the result. Individual results vary.

Why retention is for life

This patient had already lived the retention lesson once: earlier aligner movement, no retainers, and the teeth drifted back. Teeth have a natural tendency to move throughout life, alignment is not a one-time event that stays put on its own. A retainer protocol (removable trays worn nightly, a bonded wire, or a combination) is how the result is kept. One practical note we give every retainer patient: if a bonded retainer wire ever breaks, have it checked promptly.

Risks and limitations: what aligner treatment can and cannot do

No orthodontic treatment is risk-free, and expectations are part of the plan:

Effectiveness has limits. For many mild-to-moderate, non-extraction cases in adults, published reviews find aligners and braces reach comparably good end results — though the overall quality of that evidence is rated low, and complex cases are less studied [1,2]. Aligners are strongest at aligning and tipping teeth; extrusion and rotation of small rounded teeth, or large movements of molars are the least predictable movements [3]. Complex orthodontic problems are best treated by an orthodontist, and we will tell you when we think that is the case.
Refinements are normal. Most movements are not predictable enough to finish with one set of trays; additional series are a planned part of treatment, not a failure [2].
Soreness happens. Trays fit tightly by design and apply force over time. Some pain and tenderness with new trays is normal; studies find the first days tend to be more comfortable with aligners than with braces, and the difference fades after the initial period [4,5].
Speech can be affected at first. A mild lisp on “s” and “sh” sounds is common early on; most people adapt within one to two weeks [7].
Root shortening. All orthodontic tooth movement carries some risk of root resorption; with aligners, studies measure it as small on average (a pooled mean of roughly half a millimetre) [6].
Relapse. Without retention, teeth drift back — as this patient's own history showed.
Gingival recession. In some cases gingival recession can occur. This is why assess the gingival tissue at the consult appointment and limit the type of movements depending upon soft tissue and bony support.
Compliance is the engine. Trays only work while worn (~22 hours/day). Inconsistent wear desynchronizes the teeth and the trays; treatment slows or stalls. One of the most common reasons for trays not fitting is not wearing trays.
Additional risks: These are all reviewed during the initial consultation phase.

Patient questions

Will it hurt afterwards?

Some pain, tenderness and soreness of the teeth after starting Invisalign and when changing trays is normal; each tray is designed to fit snugly and apply light, controlled force over time; that force is what moves the teeth. The discomfort can be manageable with low doses of over-the-counter pain relief. In this case, the patient was advised to use the lowest effective dose of naproxen (Aleve) for one to two days after starting treatment. Whether an anti-inflammatory is suitable depends on your medical history and personal recommendation by your health provider.

You only showed the top teeth , what about the bottom?

In this case, treatment was limited to the upper arch, because that was where the chief complaint and the positional problems were. Single-arch treatment is appropriate in selected cases, but it is a deliberate decision, not a shortcut: both arches and the way they meet must be assessed first, because moving one arch changes how the teeth bite together. When lower alignment or the bite requires it, both arches are treated.

What are the bumps on my teeth?

Composite attachments: small, temporary bumps of tooth-coloured filling material that act as handles so the trays can grip, push and rotate teeth. Sometimes they are placed on teeth next to the one being moved, to serve as anchors. They are removed and polished off at the end of treatment. No drilling is involved.

Do I need a root canal before putting a crown on?

Not routinely, no. A root canal is needed when the nerve inside the tooth is irreversibly inflamed, infected or dead — not simply because a crown is planned or a tooth is moved. A healthy tooth can be crowned without one. In this case, neither was needed: after repositioning, the chipped tooth was managed with a small repair and polishing

Will my teeth look exactly like the 3D preview?

The preview is a plan, not a guarantee. Programmed movements tend to under-express or over promise, which is why plans build in overcorrection and why refinement scans and extra trays are a normal part of treatment [2,3]. In some cases the proposed plans are simply not attainable. This is why it is important for your dentist to assess the results.

What happens if I don't wear the trays enough?

Treatment doesn't just pause, the teeth and the trays fall out of sync. The fix is usually slowing the tray schedule or stepping back to the last well-fitting tray or restarting treatment. Consistent wear is one of the biggest factor in the success of Invisalign or clear aligner treatment.

How long do I have to wear the retainer?

In this case: full-time for three months, then nightly. Realistically, some form of retention continues for as long as you want the teeth to stay where they are — teeth move throughout life.

Will treatment pause if my gums bleed?

It can. Gum health and hygiene are checked at every visit, and treatment is paused if they slip, moving teeth through inflamed tissue is not something we do.

Sources

Baneshi M, O'Malley L, El-Angbawi A, Thiruvenkatachari B. Effectiveness of clear orthodontic aligners in correcting malocclusions: a systematic review and meta-analysis. J Evid Based Dent Pract. 2025;25(1):102081.
Robertson L, Kaur H, Fagundes NCF, Romanyk D, Major P, Flores Mir C. Effectiveness of clear aligner therapy for orthodontic treatment: a systematic review. Orthod Craniofac Res. 2020;23(2):133–142.
Rossini G, Parrini S, Castroflorio T, Deregibus A, Debernardi CL. Efficacy of clear aligners in controlling orthodontic tooth movement: a systematic review. Angle Orthod. 2015;85(5):881–889. Open access: PMC8610387.
Cardoso PC, Espinosa DG, Mecenas P, Flores-Mir C, Normando D. Pain level between clear aligners and fixed appliances: a systematic review. Prog Orthod. 2020;21(1):3. Open access: PMC6970090.
Li Q, Du Y, Yang K. Comparison of pain intensity and impacts on oral health-related quality of life between orthodontic patients treated with clear aligners and fixed appliances: a systematic review and meta-analysis. BMC Oral Health. 2023;23(1):920. Open access: PMC10675971.
Butsabul P, Kanpittaya P, Nantanee R. Root resorption in clear aligner treatment detected by CBCT: a systematic review and meta-analysis. Int Dent J. 2024;74(6):1326–1336.
Ali Baeshen H, et al. The effect of clear aligners on speech: a systematic review. Eur J Orthod. 2023;45(1):11–19.
Crain G, Sheridan JJ. Susceptibility to caries and periodontal disease after posterior air-rotor stripping. J Clin Orthod. 1990;24(2):84–85.

Sunny Dental Centre is a general dental practice. Dr. Mandip Puri, DDS, is registered with the Royal College of Dental Surgeons of Ontario as a general practitioner, not a specialist. Complex orthodontic problems may be best treated by an orthodontist, and we will tell you when we think that is the case. Individual results vary; what is achievable depends on your teeth, bite and goals. This case is not meant to provide a medical treatment advice, contact your dentist for individual advice.

Questions about clear aligner treatment? Sunny Dental Centre, Guelph — +1-519-824-8250.

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Invisalign Case Study: Moving a Lateral Incisor and Rebalancing the Bite