Does Invisalign Fix Overbite? What Clear Aligners Can and Cannot Do

Short answer

• Sometimes, and the size and cause of the overbite decide which times. Clear aligners, including the Invisalign system, can improve many overbites. The American Association of Orthodontists (AAO) lists overbite among the conditions aligners commonly treat, and a 2025 systematic review of deep bite treatment found that aligners can effectively correct mild to moderate overbites that are mainly a tooth position problem. The same review is clear about the limit: how well aligners work when the jaw relationship itself drives the bite is uncertain, and fixed braces performed better in those skeletal cases. Two cautions belong in the short answer. First, aligners rarely deliver the full correction shown in the digital plan. Across the studies in that review, only about a third to about a half of the planned bite opening was typically achieved, so orthodontists often plan extra correction or expect additional aligners partway through. Second, aligners move teeth. They do not move jaw bones. A severe overbite rooted in jaw position may need braces, a combined approach, or, for an adult with a large skeletal difference, orthodontics together with jaw surgery. Which group your bite falls into takes an orthodontic examination with records such as X-rays, photographs, and digital scans. It cannot be judged from a mirror or a photo. This article is general information only. It is not a diagnosis and it does not recommend a treatment for any individual. If you have an overbite you are concerned about, the useful next step is an orthodontic evaluation.

What an Overbite Is

An overbite is a vertical overlap. When the mouth closes, the upper front teeth overlap the lower front teeth from above. A small overlap is normal and healthy. Orthodontists measure the overlap in millimeters and by how much of the lower front teeth it covers.

When the overlap becomes excessive, so the upper front teeth cover most or all of the lower front teeth, orthodontists often call it a deep bite, or deep overbite. The AAO glossary defines a closed bite or deep bite in exactly those terms: the upper front teeth overlap the bottom front teeth an excessive amount. A deep bite is the form most likely to need treatment, because the lower front teeth may bite into the gum tissue behind the upper front teeth, and the teeth may wear unevenly over time.

Overbite is often confused with overjet. The two describe different directions. Overbite is vertical: how far the upper teeth overlap the lower teeth downward. Overjet is horizontal: how far the upper front teeth sit in front of the lower front teeth. A person can have one without much of the other, or both together. This article is about the vertical problem. A large overjet with protruding upper teeth is a related but different pattern, covered in our companion guide, can Invisalign fix crooked teeth.

Not every overbite needs treatment. A mild overlap with no pain, no gum injury, no unusual wear, and no difficulty chewing may simply be monitored. The American Dental Association (ADA), in its patient guidance on braces and orthodontics, notes that an uncorrected abnormal bite can contribute to harder to clean teeth, interference with chewing and speaking, abnormal enamel wear, and jaw problems. Those are reasons to have a significant overbite assessed, not a promise that every overbite causes harm.

Dental, Skeletal, and Combined Overbites

The most important question about any overbite is what is causing it. Orthodontists group the causes into three patterns, and the pattern predicts far more about treatment than how the smile looks.

Dental overbite

In a dental overbite, the jaw bones are in a broadly normal relationship, but the teeth themselves create the deep overlap. The upper front teeth may sit too far down, the lower front teeth may have erupted too far up, the back teeth may be short or worn so the bite closes too far, or a combination of these. Because the problem sits in tooth position, moving teeth can often correct it. This is the pattern where clear aligners have their strongest evidence.

Skeletal overbite

In a skeletal overbite, the relationship of the jaw bones drives the bite. The upper jaw may sit forward relative to the lower jaw, the lower jaw may sit back or be smaller, or the vertical proportions of the face may make the bite close deeply. Teeth often tilt to partly compensate, which can hide how much of the problem is skeletal. Aligners cannot reposition a jaw bone, so tooth movement alone has a ceiling here. The 2025 deep bite review found the evidence for aligners in skeletal cases uncertain and found fixed appliances more effective there.

Combined overbite

Many real cases are a mixture: a modest skeletal pattern plus dental positions that add to the depth. A combined case may improve substantially with aligners while still falling short of a textbook bite, or it may be better served by braces from the start. Only records and measurements separate the two. The opposite bite problem makes the same point: our guide to whether Invisalign can fix an underbite explains why a bite driven by jaw position responds so differently from one driven by tooth position.

How Clear Aligners Try to Open an Overbite

Invisalign is one brand of clear aligner, made by Align Technology. Other systems exist, and the mechanics here apply to clear aligner treatment generally. An aligner is a thin, clear, plastic like shell that snaps over the teeth. Treatment is a series of shells, each shaped a small step closer to the planned result, so wearing them in order applies gentle, planned pressure and moves teeth a fraction of a millimeter at a time.

The AAO describes the usual rhythm on its aligner pages. Each aligner is typically worn for one week, at least 22 hours a day. Its aligner therapy guidance gives the range as 20 to 22 hours a day, as prescribed, with each set worn for a week or two. Both forms appear in AAO material, so this article reports both. Aligners come out for eating, for drinking anything other than water, and for brushing and flossing. Treatment begins with an examination using X-rays, photographs, and digital scans, a diagnosis, and only then a digital plan.

For an overbite specifically, a plan usually combines several of these movements:

• Intrusion of the front teeth. Pressing the upper front teeth, the lower front teeth, or both slightly back into the gum reduces the overlap directly. This is the vertical movement aligners do best. Rossini and colleagues, in The Angle Orthodontist in 2015, found aligner treatment effective in controlling anterior intrusion, with a mean intrusion of 0.72 millimeters across the studies reviewed. That is real but modest, which is why intrusion alone rarely opens a deep bite fully.
• Leveling the curve of the lower teeth. The lower teeth sit along a natural curve, and deepening of that curve goes with a deep bite. Leveling it helps open the bite. A 2025 systematic review found reductions ranging from almost nothing to about 2.2 millimeters across seven retrospective studies, with predictability varying widely, from about 35 percent to about 72 percent, and every study at serious risk of bias. Leveling helps, inconsistently.
• Uprighting and moving back teeth. Tipping front teeth slightly outward, or moving upper molars back in sequence, can reduce the overlap in some patterns. Rossini and colleagues found upper molar bodily movement of about 1.5 millimeters the most predictable movement in their review, at 88 percent.
• Bite ramps and attachments. Small raised features built into the aligners behind the upper front teeth, called bite ramps, give the lower teeth something to meet and help the bite open. Tooth colored attachments, small bonded shapes of dental composite, give the tray a surface to grip and push against. The AAO notes that attachments are frequently placed to help guide teeth into place. The deep bite review found bite ramps showed minimal additional benefit where measured, so they are a common plan feature, not a guarantee.
• Elastics. Small orthodontic rubber bands worn between the upper and lower teeth, hooked to attachments, buttons, or cutouts in the trays, help correct how the two arches meet. A tray on one arch alone cannot do that. The AAO confirms that aligners can be paired with traditional orthodontic elastics. Like the trays, elastics only work while they are worn.

One movement deserves a warning, because deep bite plans sometimes depend on it. Extrusion, drawing a tooth outward from the gum, for example to lift short back teeth so the bite opens, was the most difficult movement to control in the Rossini review, at about 30 percent accuracy, followed by rotation. A plan that needs a lot of extrusion deserves careful questions about its promised result.

What the Evidence Actually Shows

The most directly relevant evidence is the systematic review by Husain and colleagues, published in Clinical Oral Investigations in 2025, which examined clear aligners for deep bite correction specifically. The reviewers screened 829 studies and included 18:

• Bite opening achieved with aligners ranged from 0.4 millimeters to 3.8 millimeters.
• Accuracy, meaning how much of the planned correction was actually achieved, ranged from about 33 percent to about 49 percent. Patients typically got roughly a third to a half of the bite opening the software had planned.
• The evidence for both accuracy and effectiveness was rated low quality under the GRADE system, because of high risk of bias, indirectness, and imprecision, even though findings were consistent across studies.
• Aligners could effectively correct mild to moderate dentoalveolar deep bites. Dentoalveolar means the problem sits in the teeth and the bone that holds them, rather than in the jaw relationship.
• For skeletal deep bites, effectiveness compared with full fixed braces remained uncertain, and aligners were less effective than fixed appliances for skeletal cases.
• Because planned correction so often fell short, overcorrection in the plan, or refinements later, were necessary to reach the intended result. Recommending aligners as a superior way to correct a deep bite would be premature, the reviewers concluded.

A wider comparison points the same way. Ke, Zhu, and Zhu, in BMC Oral Health in 2019, compared clear aligner and fixed appliance therapies across eight studies. Both approaches were effective overall. Aligners were not as effective as braces at producing adequate occlusal contacts, controlling tooth torque, increasing transverse width, and retention. Treatment duration was shorter in the aligner groups, a group finding, not a promise about any individual case.

Taken together, the evidence supports a measured claim: aligners genuinely open many mild to moderate dental overbites, by a few millimeters, in patients who wear them as directed. It does not support the louder claims that the result on screen is the result you will get, or that aligners match braces for every depth and cause of overbite.

The Severity Spectrum: Where Aligners Fit, and Where They Struggle

Mild overbite, mainly dental

This is the strongest case for aligners. The overlap is increased but the lower front teeth are still partly visible, the jaw relationship is broadly normal, gum and tooth health are good, and the movements needed are mainly intrusion, leveling, and tipping, the movements aligners perform most predictably. With consistent wear, attachments where planned, and elastics if prescribed, many of these cases finish well.

Moderate overbite

Aligners remain a reasonable option for many moderate dental overbites, the group the 2025 review describes as effectively treatable. Expectations need adjusting, though. The plan will likely build in overcorrection, refinements should be assumed rather than treated as a surprise, and the final bite may be a clear improvement rather than a textbook result. Ask at the start how much opening is planned, how much is realistically expected, and what the fallback is if the bite does not open as hoped.

Severe or skeletal overbite

This is where aligners alone struggle. Warning signs include upper teeth covering the lower front teeth completely, lower teeth biting into the palate tissue, a visibly unbalanced jaw relationship, major crowding or missing teeth alongside the deep bite, or jaw pain or significant wear. Here, fixed braces give direct control over each tooth, including vertical movements and root position that trays control poorly, and they work around the clock without depending on wear time. For a growing teenager, growth guidance with other appliances may be part of the plan. For an adult whose overbite is driven by a large skeletal difference, the realistic route can be orthodontics combined with jaw surgery. The ADA patient guidance describes that route plainly: some patients have a jaw that sticks out and makes the bite uneven, and in some cases surgery is needed to improve the function and appearance of the bite. Being steered toward braces or a surgical consultation is not a failure of aligners. It is the diagnosis deciding the tool.

Clear Aligners Compared With Braces for an Overbite

The AAO publishes a side by side comparison of braces and aligners. The table below follows it, with the deep bite evidence added to the final row.

Feature	Clear aligners	Braces
Visibility	Virtually invisible clear plastic trays	Visible wires and brackets; metal or tooth colored ceramic options
Removability	Removable, but must be worn at least 22 hours a day	Fixed to the teeth and not removable
Eating	Removed for meals, so no food restrictions	Hard, sticky, and chewy foods avoided to protect brackets and wires
Cleaning	Teeth brushed and flossed normally; teeth must be clean before trays go back in	Meticulous brushing and flossing around brackets and wires
Discomfort	When switching to a new set of trays; usually easily managed	When placed or adjusted; typically short lived
Treatment scope	Effective for many problems, but suitability is case dependent	Can treat most orthodontic problems
Overbite evidence	Mild to moderate dental deep bites correct effectively, but only about a third to about a half of the planned opening is typically achieved	More effective than aligners for skeletal deep bites in the 2025 review; more direct control of vertical movement and torque

The AAO’s central point is that no single appliance is inherently better than the other. The choice follows the diagnosis, the goals of treatment, and the patient’s lifestyle. Discretion is a legitimate part of that judgement, and adults who present in public sometimes weigh it heavily; our guide to how to build confidence in public speaking covers the wider confidence side of that concern. Appearance should sit alongside the movement evidence, though, not instead of it.

Teenagers, Growth, and Adults

Age changes the overbite conversation, because growing jaws can be guided and finished jaws cannot. The ADA notes that treatment beginning while a child is growing helps produce the best results, that most treatment begins between ages 8 and 14, and that aligners are available for teens and adults. The AAO recommends a first orthodontic check by age 7, so a developing deep bite can be watched and timed.

For a teenager with a deep bite, the questions are about growth remaining, whether the lower front teeth have finished erupting, and whether wear time will survive school, sports, and snacks. Some teen plans use aligner features designed to encourage the lower jaw forward while the teeth align, a growth dependent approach with no equivalent in an adult jaw. Families will find the companion guide on Invisalign for teens, written for parents useful, and our comparison of orthodontics for teens sets aligners alongside braces for the same age group.

Adults bring different considerations: no growth to recruit, sometimes worn or restored teeth, and occasionally gum disease or missing teeth to manage first. None of that rules aligners out, and healthy teeth can be moved at any adult age. The skeletal ceiling matters more, though, because an adult skeletal overbite cannot be grown out of, which is why the braces or surgical discussion appears more often in adult severe cases. Adults weighing cost and expectations may also find our guide to whether Invisalign is worth it for adults helpful.

Daily Life With Aligners: Wear, Cleaning, and Refinements

No part of an overbite plan matters more, day to day, than wear time. An aligner only moves teeth while it is in the mouth. A tray left in its case through a long lunch and an evening out has delivered no intrusion that day, and teeth that fall behind the plan stop fitting the next tray properly. The AAO is blunt that success relies heavily on compliance, and that inconsistent wear can extend treatment or compromise the result. Honest self assessment is therefore part of candidacy. Frequent snacking makes aligner life harder, because every eating occasion restarts a remove, eat, clean, and replace cycle. Readers who graze through the day may find our guide to hydration and healthy snack swaps for workdays practical for the same reason: fewer, planned eating occasions fit more easily around an appliance worn almost all day.

Cleaning carries its own risk. The AAO warns that aligners can trap liquids and food particles against the teeth, increasing the risk of cavities and gum disease, and that soft drinks, flavored waters, and sports drinks must be avoided with aligners in, because liquid seeps under the tray and acid or sugar held against enamel can rapidly stain teeth and cause extensive decay. Teeth need to be spotless when aligners go back in. Brush after eating before reinserting, drink only water with trays in, and keep routine dental checkups running alongside orthodontic visits, as our guide to how often you should go to the dentist explains. Bleeding gums during treatment deserve attention in their own right; our article on the signs of gum disease sets out which warning signs need a dental appointment.

Refinements deserve a plain explanation, because overbite plans need them so often. A refinement is a fresh scan partway through or near the end, followed by an additional series of aligners to finish movements that fell short. Given the accuracy figures above, refinements and planned overcorrection are normal, not a sign that treatment has failed. Ask at the start whether refinements are expected and how many rounds are included in the fee.

What the Manufacturer Says, and How to Weigh It

Align Technology, the company that makes Invisalign, states on its own overbite page that Invisalign treatment can fix an overbite, describes the aligners as virtually invisible, comfortable, and faster than braces, and lists deep bites and overbites among the complex cases the system is marketed to treat. Those are manufacturer claims, presented here as claims, not as findings of this article. Two need the evidence held next to them. Faster is not established for an individual: the comparative review found shorter duration only as a group average in a small set of studies, with braces ahead on bite contacts and torque control. Can treat complex cases describes what the system is prescribed for, while the peer reviewed deep bite review rates the underlying evidence as low quality and finds fixed appliances more effective for skeletal bites. Use manufacturer material as questions, not as an answer: ask what result, in millimeters, the orthodontist expects in your bite.

Retention: Keeping the Bite Open

Finishing the last aligner is not the end of treatment. Without a retention phase, teeth tend to move back toward their starting positions, called relapse, and a bite that was opened can deepen again. The AAO states that all orthodontic patients need retainers after treatment, whichever appliance was used. The Cochrane review of retention procedures, updated in 2023 and covering 47 studies with 4,377 participants, states the same background: without retention, teeth tend to relapse, and almost every person treated will require some type of retention. It is honest that the evidence comparing retainer types is low to very low certainty, so no single retainer can be presented as proven best. Its population was patients treated with braces, a further reason to follow your own clinician’s plan.

Retainers are removable, including clear plastic retainers that look like a passive aligner, or fixed, typically a thin wire bonded behind the front teeth. Wear the retainer exactly as advised, for as long as advised, commonly long term and often indefinite part time wear, and report a lost, broken, or ill fitting retainer promptly. Our guide to what you should know before you get a retainer covers types and replacement in full.

Questions to Ask an Orthodontist About Your Overbite

• Is my overbite mainly dental, mainly skeletal, or a mixture, and how did the records show that?
• How deep is it in millimeters, and how much opening do I actually need?
• How much opening do you plan with aligners, and how much do you realistically expect to achieve?
• Which movements does my case need, and which are least predictable with trays?
• Will I need attachments, bite ramps, or elastics, and what does each one do in my plan?
• Would braces, or a combined approach, give a more predictable result, and why?
• Is jaw surgery part of the honest conversation for my case, now or as a fallback?
• How many hours a day must I wear the aligners, and how often will progress be checked?
• Are refinements and planned overcorrection expected, and are they included in the fee?
• What is the total cost, including refinements, replacement trays, and retainers?
• What is the retention plan afterwards: what type, worn how often, and for how long?

Clear, specific answers tied to your own examination are the sign of a careful assessment.

Frequently Asked Questions

Does Invisalign fix overbite completely?

For many mild to moderate dental overbites, aligners can bring the bite into a healthy, functional range. Complete correction to a textbook measurement is less certain. Only about a third to about a half of the planned opening was typically achieved in the studies reviewed, which is why overcorrection or refinements are often planned. Severe and skeletal overbites are less likely to be fully corrected with aligners alone.

How long does Invisalign take for an overbite?

There is no honest single figure. The ADA gives a general range of one to three years for most people wearing braces or aligners, depending on what needs correcting, followed by a retainer period. An individual estimate depends on the depth and cause of the overbite, wear time, and whether refinements are required. Be cautious of any timeline offered before an examination with records.

Do I need braces instead of aligners for my overbite?

Not necessarily. Many overbites can be treated with aligners, and many severe, complex, or skeletal cases are better served by braces or a combined plan. The deciding factors are the cause and severity of the overbite, your age and remaining growth, and whether you can wear aligners as directed. An orthodontic examination is the way to decide.

Will I need elastics or attachments with aligners for an overbite?

Often, yes. Attachments help aligners grip and guide teeth, and elastics between the arches help correct how the bite meets, which a tray on one arch cannot do alone. Bite ramps are also common in deep bite plans, although studies found minimal additional benefit from them. None of these is a sign that a case has gone wrong. Each only works while it is used as directed.

Will my overbite come back after aligners?

It can, if retention is not worn as directed. Teeth tend to drift back after any orthodontic treatment, and a corrected bite can deepen again. Retention is part of the treatment, not an optional extra. Ask how long retention is expected in your case, and what to do if a retainer is lost or stops fitting.

Can adults fix an overbite with aligners, or is it only for teenagers?

Adults can be treated with aligners, and the basic process of moving teeth is the same at any age. The difference is growth. A teenager may still have jaw growth that can be guided, while an adult skeletal overbite cannot be changed by growth, so severe adult cases are more likely to involve braces or surgery.

Sources & references

• American Association of Orthodontists (AAO), Clear Aligners: Discreet Ways to Straighten Teeth, aaoinfo.org. Clear aligners as nearly invisible plastic shells applying gentle pressure; each aligner typically worn for one week, at least 22 hours a day, moving teeth a fraction of a millimeter at a time; removal for eating, drinking, and brushing and flossing; overbite listed among the conditions aligners commonly treat; aligners not right for everyone, with braces, a combination, or elastics paired with aligners recommended case by case.
• American Association of Orthodontists (AAO), Clear Aligner Therapy: The Discreet Way to Straighten Teeth, aaoinfo.org. Wear of 20 to 22 hours a day as prescribed, with each set worn for a week or two; assessment with X-rays, photos, and digital scans and a diagnosis before the plan is designed; moving teeth as a complex biological process needing start to finish supervision; limits for severe malocclusions, significant rotations, and large gaps, where braces may offer more precision; success heavily dependent on compliance; aligners can trap liquids and food particles against the teeth, increasing the risk of cavities and gum disease.
• American Association of Orthodontists (AAO), Aligners vs. Braces: A Comparison, aaoinfo.org. No single right way to do orthodontic treatment and no appliance inherently better than another; diagnosis from orthodontic records (X-rays, photos, and models) as the starting point; side by side comparison of visibility, removability, diet, hygiene, discomfort, and treatment scope; tooth colored attachments frequently placed to help guide teeth into place; all patients need retainers after treatment; teeth must be spotless before aligners are placed; sugary and acidic drinks with aligners in can rapidly stain teeth and cause extensive decay.
• American Dental Association (ADA), Patient Education, Braces and Orthodontics (MouthHealthy content). Braces as the most common way to correct crooked teeth and major bite problems, with other treatments for less severe cases; consequences an uncorrected abnormal bite can cause, including harder to clean teeth leading to decay, gum disease, and tooth loss, interference with chewing and speaking, abnormal enamel wear, and jaw problems; braces as brackets cemented to the teeth connected by a wire that is regularly tightened; aligners as clear trays worn over the teeth, removed before eating, brushing, and flossing; surgical correction where a jaw sticks out and makes the bite uneven; treatment while a child is growing helps produce the best results, most treatment begins between ages 8 and 14, and aligners are available for teens and adults; most people wear braces or aligners for one to three years, followed by retainers.
• Husain, F., Riccardi, J., Alletto, L., Stellrecht, E., Bejehmir, A. P., and Al-Jewair, T., Effectiveness and accuracy of clear aligners in treatment of deep bite: a systematic review, Clinical Oral Investigations, 2025, 29(6), 306, PubMed PMID 40394411. Eighteen studies from 829 screened: bite opening with aligners ranged from 0.4 to 3.8 millimeters; accuracy of deep bite correction ranged from about 33 percent to about 49 percent; GRADE rated the evidence low quality for both accuracy and effectiveness; clear aligners can effectively correct mild to moderate dentoalveolar deep bites; efficacy in skeletal cases compared with full fixed appliances remains uncertain and aligners are less effective than fixed appliances for skeletal cases; planned correction often falls short, making overcorrection or refinements necessary; recommending aligners as a superior modality for deep bite correction is premature.
• Rossini, G., Parrini, S., Castroflorio, T., Deregibus, A., and Debernardi, C. L., Efficacy of clear aligners in controlling orthodontic tooth movement: a systematic review, The Angle Orthodontist, 2015, 85(5), 881 to 889, PubMed PMID 25412265. Eleven studies: aligners align and level the arches and are effective in controlling anterior intrusion, with mean intrusion of 0.72 millimeters, but not anterior extrusion; extrusion was the most difficult movement to control at about 30 percent accuracy, followed by rotation, with rotation of rounded teeth not effectively controlled; upper molar distalization showed the highest predictability at 88 percent for bodily movement of at least 1.5 millimeters; conclusions to be read with caution because of the number, quality, and heterogeneity of the studies.
• Zanatta, S., and colleagues, The Efficacy of Clear Aligners in Leveling the Curve of Spee: A Systematic Review, Applied Sciences, 2025, 15, 9719. Seven retrospective studies in adults: leveling of the lower tooth curve ranged from about 0.01 to 2.2 millimeters; anterior intrusion was achieved to a limited extent and posterior extrusion was inconsistent; predictability varied from about 35 percent to about 72 percent; all studies were judged at serious risk of bias and the certainty of evidence was low to very low; no study reported long term stability.
• Ke, Y., Zhu, Y., and Zhu, M., A comparison of treatment effectiveness between clear aligner and fixed appliance therapies, BMC Oral Health, 2019, 19, 24. Eight studies, two randomized trials and six cohort studies, all involving the Invisalign aligner: both aligners and braces were effective in treating malocclusion; aligners were not as effective as braces in producing adequate occlusal contacts, controlling tooth torque, increasing transverse width, and retention; treatment duration was shorter in the aligner groups in the included studies, a group finding and not an individual promise.
• Martin, C., Littlewood, S. J., Millett, D. T., and colleagues, Retention procedures for stabilising tooth position after treatment with orthodontic braces, Cochrane Database of Systematic Reviews, 2023, CD002283, PubMed PMID 37219527. Forty seven studies with 4,377 participants, in patients treated with braces: without a retention phase, teeth tend to relapse to their initial position, and almost every person who has orthodontic treatment will require some type of retention; the evidence comparing retainer types and strategies is low to very low certainty, so no single approach can be presented as proven best.
• Align Technology, Invisalign, Overbite causes and treatment with Invisalign aligners, and Can Invisalign Treat Complex Cases?, invisalign.com. Manufacturer pages, cited only for Align Technology's own claims, attributed as such in the article text: that Invisalign treatment can fix an overbite, that the aligners are described as virtually invisible, comfortable, and faster than braces, and that deep bites and overbites are listed among the complex cases the system is marketed to treat. These claims were weighed against the independent systematic reviews above and were not relied on as neutral evidence of effectiveness.