The effects of Le Fort I osteotomies on velopharyngeal and speech functions in cleft patients

If you’ve ever had a conversation with an orthodontic or maxillofacial surgeon, you’ve probably heard the term “Le Fort I osteotomy” thrown around like it’s a casual brunch topic. But don’t worry—this isn’t some medieval torture technique (though patients might beg to differ post-op). It’s actually a routine and life-changing surgical procedure used to correct conditions like vertical maxillary excess, midface hypoplasia, and anterior open bite. Basically, it’s the orthodontic equivalent of upgrading from a flip phone to a smartphone—function meets aesthetics in the best way possible.

As surgeons started routinely repositioning the maxilla in the late ’70s, they noticed something peculiar—some patients who had undergone cleft palate repairs started experiencing changes in their speech post-surgery. And not just a “my voice sounds weird on a voicemail” kind of change, but significant alterations that could be temporary or, in some cases, permanent. This led to an influx of studies trying to figure out exactly what was happening and why. Because let’s face it, no one signs up for surgery expecting to sound like they just inhaled helium for life.

The Root of the Problem: It’s All About the Muscles (and Scars)

Speech issues in cleft patients boil down to a mix of developmental malformations, scarring, and structural obstacles in the oral and pharyngeal regions. Picture a team of musicians where half the instruments are missing, and the rest are playing in the wrong key—yeah, not great for clear articulation. The muscles involved in lifting the soft palate (like the levator veli palatini) and their antagonists (like the palatoglossus) often develop improperly, leading to speech challenges. Add in post-surgical scar tissue, oronasal fistulas, and crossbites, and you have a recipe for some serious phonetic acrobatics.

VPI: When Airflow Has a Mind of Its Own

One of the biggest speech-related concerns in cleft patients is velopharyngeal insufficiency (VPI)—a fancy way of saying the velum (soft palate) and pharyngeal wall aren’t sealing off the nasopharynx properly during speech. This results in excess air escaping through the nose, making speech sound overly nasal, like someone permanently stuck in the middle of a bad cold. On the flip side, some patients with severe midface deficiency develop hyponasality, where the nasal passage is too blocked, making them sound like they have a clothespin on their nose.

Then there are articulation defects, where certain consonants refuse to cooperate. Think of sibilants (like ‘s’ and ‘sh’), fricatives (like ‘f’ and ‘v’), and plosives (like ‘p’ and ‘b’) suddenly staging a rebellion. These errors can result from anatomical misalignment, making the production of crisp, clear sounds a daily challenge.

So, What Does Surgery Actually Do to Speech?

Studies have tried to pin down exactly how maxillary surgery impacts speech, but results have been all over the place—partly because speech is complicated and partly because patient samples have been small and assessment methods inconsistent. However, some trends are clear:

  • Maxillary advancement can improve speech for some patients by providing better tongue space and articulation.
  • Others may experience temporary speech regression as their muscles adjust to the new positioning.
  • For cleft patients with pre-existing VPI, surgery might actually worsen velopharyngeal function, requiring additional speech therapy or even secondary surgeries.

📊 Study Breakdown: The Who, What, and How

👥 Patients: The Speech Test Subjects

Total Patients Enrolled80
Patients with Complete Data54
Gender Distribution37 Male, 17 Female
Age Range at Surgery8 – 33 years

💡 Fun Fact: Speech evaluations were taken anywhere from 3 months to 6 years post-op—because, let’s face it, speech takes its sweet time adjusting.

🛠️ Surgery Types: The Maxillary Makeover

Surgical ProcedurePatients (n=54)
Le Fort I Advancement Only34
Le Fort I + BSSO (Mandibular Setback)20

💬 Translation: 34 patients got a one-way ticket to maxillary forward town, while 20 had their mandible set back to balance the whole look. 😁

🗣️ Speech Evaluation: The Verbal Verdict

To keep things scientific (but still understandable), speech was assessed using a system developed in 1979 by McWilliams and Phillips at the University of Pittsburgh. And yes, it’s been around longer than most of us.

🔎 What Was Measured?

1️⃣ Hypernasality (aka the unintentional nose filter)

  • Scored from 0 (normal) to 4 (severe hypernasality)

2️⃣ Hyponasality (think: permanently stuffed nose sound)

  • Rated as: 0 = none, 2 = moderate/severe

3️⃣ Articulation Errors 🎙️

  • Measured in sibilants, fricatives, and plosives (aka the sounds that make or break clear speech)

4️⃣ Velopharyngeal Valve Function 🚪

  • Classified as:
    • 0 = Normal
    • 1-2 = Borderline competent
    • 3-6 = Borderline incompetent
    • 7+ = Incompetent (oops…)

📉 Speech Score Breakdown

Speech ScoreVP Valve Status
0Normal 🟢
1-2Borderline competent 🟡
3-6Borderline incompetent 🟠
7+Incompetent 🔴

💡 The Big Question: Did the surgery help or hurt speech? Well…

  • Some patients improved 🎉
  • Some stayed the same 🤷‍♂️
  • And a few had new speech issues 🤦‍♀️

📉 Speech at 3 Months Post-Surgery: The Plot Thickens

The biggest shocker? A general decline in velopharyngeal competence. Before surgery, 42% of patients had normal VP function. Three months later? Just 18%! 🚨

🔍 VP Mechanism Changes Post-Surgery

VP StatusPre-Surgery (%)Post-Surgery (%)
Competent 🟢42% (23)18% (10)
Borderline Incompetent 🟡9% (5)22% (12)
Complete VPI 🔴13% (7)20% (11)

💬 Translation: Speech went from “I got this” to “Houston, we have a problem.” 🚀

Overall speech scores? Worse. 😬

  • Pre-surgery average: 2.46
  • Post-surgery average: 4.24
  • And yes, it was statistically significant (P < .05).

🎤 Articulation: A Silver Lining?

Not all was lost! Articulation defects—like trouble with fricatives, plosives, and sibilants—actually improved slightly.

Articulation DefectsPre-Surgery (%)Post-Surgery (%)
Any Speech Defect84% (46)73% (40) ✅
Errors Related to Anterior Dentition64% (35)47% (26) ✅

💡 Moral of the story? If you’re struggling with anterior sounds before surgery, you might get a speech upgrade. But if your VP function is already on the edge… buckle up.

🔄 Hypernasality vs. Hyponasality: The Great Speech Shuffle

One of the quirks of Le Fort I advancement? Some patients swap speech issues like a game of Uno. 🎭

Speech ConditionPre-Surgery (n)Post-Surgery (n)
Hyponasality (Stuffed Nose Sound)188 ✅
Mild Hypernasality (Nasal Twang)1016 ❌
Moderate Hypernasality28 ❌
Severe Hypernasality21 ✅

🔄 So if you went in sounding blocked, there’s a chance you walked out with a bit too much air coming through instead!

👥 Does the Type of Surgery Matter?

Group 1: Le Fort I Only

  • Pre-surgery articulation defects: 88% 🗣️
  • Post-surgery: 74% ✅

Group 2: Le Fort I + BSSO (Mandibular setback included)

  • Pre-surgery articulation defects: 75%
  • Post-surgery numbers cut off (sorry, suspense lovers!)

👉 Moral of the story? It doesn’t seem to matter if you just advance the maxilla or combine it with a mandibular setback—speech still takes a hit!

🔬 Pharyngeal Flaps: Helping or Hurting?

18 patients had a pharyngeal flap before surgery. Here’s how they fared:

  • 9 got worse 😵
  • 8 stayed the same 🤷
  • 1 got better 🎉

Not exactly an inspiring success rate.

📖 The Great Speech Debate: Who Said What?

Team “Maxillary Advancement Worsens VPI” 🚨

  • Schwartz & Gruner (1980s): 84% of cleft patients had worse velopharyngeal function at 4 months post-op. 😬
  • Mason et al. (1980): Cleft patients are at higher risk of hypernasality due to their unique anatomy.
  • Witzel (1990s): If you were borderline VPI before surgery, you’re at major risk afterward.

🔎 Translation? If your velopharyngeal valve was iffy before surgery, it might throw in the towel afterward.

Team “Speech Stays the Same (or Improves)!” 🎉

  • McCarthy et al. (1980s): No increase in VPI, but yes, articulation changed.
  • Dalston & Vig (1984): No articulation improvement (speech therapists, you can relax).
  • Witzel et al. (University of Pittsburgh, 1990s): Dental occlusion affects articulation, and correcting the bite can help!
  • Ruscello et al. (1990s): 85% of patients with pre-op articulation defects improved within 6 months.
  • Vallino (1987): 88.2% of patients saw speech improvements post-op.

🔎 Translation? If your main issue is articulation errors from a bad bite, then surgery could be your speech therapist in disguise.

Our 54-patient study found:
1️⃣ More patients developed borderline incompetence or full-blown VPI post-op 🤦
2️⃣ Reduced intraoral air pressure made sibilants, fricatives, and plosives harder to pronounce
3️⃣ Velar closure during speech became incomplete, leading to nasal air leakage

So, we’re leaning toward maxillary advancement potentially worsening VP function. But does this mean doom for all cleft patients? Not necessarily!

🎭 The Balancing Act: Beauty vs. Speech?

🦷 Pros of Le Fort I Advancement:
✅ Better bite & occlusion 🦷
✅ Improved articulation (for some) 🎤
✅ Aesthetically pleasing results ✨

🚨 Cons of Le Fort I Advancement:
❌ Higher risk of hypernasality 🗣️
❌ VPI might worsen (especially in cleft patients) 😷
❌ Some sounds (like “s” and “p”) might become trickier

🤔 So, Should We Be Worried?

Not necessarily! Here’s what to consider:
🔹 If your velopharyngeal function is already borderline, be cautious.
🔹 If you have articulation issues from malocclusion, surgery might help!
🔹 Speech therapy post-op can help retrain articulation and airflow.

🎤 The Curious Case of Pharyngeal Flaps

If you’re one of the lucky 18 who had a pharyngeal flap before maxillary advancement, congratulations! 🎉

💡 Key Findings for Pharyngeal Flap Patients:
👉 50% of them improved or retained their pre-surgical speech function.
👉 67% were already in the “competent or borderline competent” speech category pre-op.
👉 Hyponasality cases dropped. (Since advancing the maxilla opened things up.)

🎯 Moral of the story? If you’re prone to VPI, a pharyngeal flap might be your best friend before Le Fort I surgery. But don’t rush into it post-op! Give it at least a year before considering further surgery.

🤔 To Advance or Not to Advance?

Maxillary advancement surgery is a balancing act—you win in aesthetics & occlusion but might lose a bit in speech function. 😵‍💫

👑 Winners:
✔️ People with articulation errors from a bad bite (Your “s” sounds are about to get crisp! 🍏)
✔️ Those suffering from hyponasality (Breathing free at last! 😮‍💨)

🚨 Potential Strugglers:
❌ Patients already borderline for VPI (Things might get worse. 🙈)
❌ Those at risk for hypernasality (Your voice might sound like it’s permanently in helium mode. 🎈)

Le Fort I is like buying a new, expensive phone—better features, but you might drop a few calls (aka speech issues). 📱📉

👂 Key Takeaways:
1️⃣ Articulation = Likely to improve.
2️⃣ Hypernasality = May get worse.
3️⃣ VPI = Can be a concern, especially for cleft patients.
4️⃣ Pharyngeal flaps = Might help, but timing is key!

Genetics of Cleft Palate and Velopharyngeal Insufficiency

“Fusion? Pfft. We’d rather make history!” declared the medial nasal processes.

And so, clefting was born—a gap not only in the developing palate but in the hearts of speech therapists everywhere.

Fusion Fumbles and Speech Stumbles
Now, when these tiny rebels refuse to join forces, chaos ensues. The velopharynx—a fancy name for the barrier between the nose and mouth—ends up with a few, shall we say, drafty construction errors. Air escapes, speech gets funky, and suddenly, “baby babble” sounds like a wind tunnel experiment gone wrong.

Enter the surgeons, the unsung heroes of tiny palates everywhere. Their mission? To bring order to the mayhem and ensure that future toddlers don’t accidentally sound like they’re narrating their own ghost stories.

A Historical “Patchwork” Approach
In 1865, Passavant was the first brave soul to attempt fixing the velopharynx by—wait for it—sticking the soft palate to the back of the throat. It’s the medical equivalent of solving a door draft problem with duct tape.

Then came Sloan in 1875 with the pharyngeal flap, followed by Padgett in 1930, who made it official in the U.S. The problem? If you don’t size it right, congratulations! You’ve now upgraded from speech issues to obstructive sleep apnea. Talk about overachieving.

Surgical Glow-Ups and the Quest for the Perfect Fix
Wilfred Hynes in 1950 got creative with myomucosal flaps, because nothing says “innovation” like rearranging muscles with names longer than your prescription list.

The technique kept evolving, because, let’s be real—every surgeon wants to leave their mark. Jackson, Silverton, and Riski all came in with their own spin, probably in a fierce game of “Whose Flap Is It Anyway?”

And then there was posterior pharyngeal wall augmentation—the surgical version of “filling in the blanks.” Early attempts included Vaseline (yes, really) and a parade of materials like porous polyethylene, collagen, and even calcium hydroxyapatite. Because when in doubt, throw some fancy-sounding stuff at it and hope for the best.

Velopharyngeal Anatomy: The Hidden Orchestra of Speech 🎤🎼

🎻 Levator Veli Palatini: The Conductor
Imagine a maestro standing center stage, arms raised, ready to lead the symphony. That’s the levator veli palatini—responsible for lifting the velum like a curtain, sealing off the nasal and oral cavities. Originating from the petrous part of the temporal bone, its fibers cross in the middle, forming a muscular sling. One contraction, and voilà! The velum retracts at a dramatic 45-degree angle to close the velopharyngeal port.

Translation: Without this guy, your words would sound like they were broadcast from inside a wind tunnel.

🎤 Musculus Uvulae: The Backup Singer
Tucked inside the levator’s muscular sling is the musculus uvulae, a tiny but mighty performer. Unlike other muscles, it has no external attachments—it’s a self-sufficient diva that adds bulk to the velum, fine-tuning closure and ensuring speech clarity.

Think of it as the vocal reverb effect for your natural sound system.

🎺 Tensor Veli Palatini: The Stage Crew
What’s a good performance without proper sound balance? Enter the tensor veli palatini, responsible for opening the Eustachian tube during yawning and swallowing. Its tendon takes a dramatic turn around the hamulus of the medial pterygoid plate, ensuring proper ear drainage and pressure equalization.

Fun fact: In cleft palate cases, this muscle’s dysfunction is why kids get chronic ear infections—basically, a feedback loop of middle ear fluid that even the best sound engineers (otolaryngologists) struggle to fix.

🥁 Superior Pharyngeal Constrictor: The Percussionist
Finally, we have the superior pharyngeal constrictor, a multitasking powerhouse made up of four muscle segments (pterygopharyngeal, buccopharyngeal, mylopharyngeal, and glossopharyngeal). It provides the lateral and posterior walls of the pharynx, tightens during speech, and even forms Passavant’s ridge, a temporary bulge that helps close the velopharyngeal port.

In simple terms, it’s the drummer keeping the beat, ensuring speech stays rhythmic and not riddled with air leaks.

🏋️ Palatopharyngeus: The Weightlifter
Muscle Motto: “No food left behind!”

The palatopharyngeus is your posterior tonsillar pillar’s personal trainer. This vertically-oriented muscle starts at the soft palate, extends to the pharyngeal walls and thyroid cartilage, and has one big job—preventing food from making an unscheduled detour into your nasopharynx.

💪 Workout Routine:
✅ Pulls lateral pharyngeal walls inward (creating the Passavant ridge).
✅ Assists the levator veli palatini in velopharyngeal closure.
✅ Helps push food down like a conveyor belt at an airport security check.

Without it, your food might just take a U-turn and end up where it doesn’t belong (hello, awkward nose sneezes).

🏃 Palatoglossus: The Yoga Instructor
Muscle Motto: “Balance is everything.”

The palatoglossus loves flexibility—literally. Found in the anterior tonsillar pillar, it connects the velum to the tongue and works as a direct antagonist to the levator veli palatini.

🧘 Workout Routine:
✅ Lowers the velum (undoing the lift from levator veli palatini).
✅ Helps open the velopharyngeal port for breathing and speech.
✅ Elevates the back of the tongue—because someone has to push food toward the esophagus.

This muscle is basically the chill mediator in the gym, making sure the soft palate and tongue don’t get into a tug-of-war.

🚴 Salpingopharyngeus: The Gym Regular (But No One Knows Why)
Muscle Motto: “I’m just here for the vibes.”

The salpingopharyngeus shows up to the gym but doesn’t seem to have any major responsibilities. It originates near the Eustachian tube and hangs out with the palatopharyngeus, but its function is… well, kind of optional.

🤷 Workout Routine:
✅ Moves the pharynx a little.
✅ Sort of helps with swallowing.
✅ Exists.

Basically, it’s like that guy in the gym who always stretches but never actually lifts anything.

⚡ Nerve Trainers: Keeping the Gym in Check
🧠 Vagus Nerve (Pharyngeal Plexus) – The Boss
✅ Controls levator veli palatini, palatopharyngeus, salpingopharyngeus, and all pharyngeal constrictors.
✅ Makes sure velopharyngeal closure happens (otherwise, you’d sound permanently nasal).

🧠 Mandibular Division of Trigeminal Nerve – The Specialist
✅ Only works on tensor veli palatini (because even the velum needs a specialist for ear pressure equalization).

With these muscles working together, you get clear speech, safe swallowing, and minimal nasal food disasters. But if even one muscle skips leg day (or, in this case, velopharyngeal closure day), things can get messy fast.

So, next time you speak, eat, or yawn, thank your Velopharyngeal Team—they’re always working out, even when you’re not!

The Architectural Flaws and Functional Fixes
Think of the velopharyngeal port as a soundproof door between the nasopharynx and oropharynx. In a normal setup, the levator veli palatini acts like a hinge, lifting the velum to close the door for clear speech. But in cleft palate, that hinge is broken—or rather, misaligned—leading to some major structural and functional issues.

🏗️ What Goes Wrong in Cleft Palate?

Levator Veli Palatini’s Great Misplacement

Normally, this muscle runs horizontally to pull the velum up and back, sealing off the nasopharynx.
In cleft palate, the muscle is discontinuous and positioned longitudinally, inserting onto the hard palate instead.
🚨 Consequence? The velum can’t reach the posterior pharyngeal wall, causing velopharyngeal insufficiency (VPI).
💬 Result? Hypernasal speech and air leakage through the nose while speaking.


The Tensor Veli Palatini’s Failed Pulley System

Normally, the tensor veli palatini works with the levator veli palatini to open the Eustachian tube, preventing middle ear infections.
In cleft palate, the levator’s faulty position disrupts this mechanism, leading to:
✅ Chronic ear infections (otitis media)
✅ Hearing loss (affecting 10–30% of cleft patients)

🎤 How Velopharyngeal Closure Happens (or Doesn’t)
Velopharyngeal closure is like sealing off a room for perfect acoustics—except that people use different methods to achieve it:

🔵 Circular Closure → The Team Effort

The velum and pharyngeal walls both contribute equally.
Ideal for balanced speech production.


⚫ Coronal Closure → Velum-Dominant Approach

The velum does most of the work, moving backward to close the port.
Most common pattern in normal speakers.


🟡 Sagittal Closure → Pharyngeal Walls Take Over

The lateral pharyngeal walls move toward the midline, with less velar involvement.
Less common but seen in some individuals.


👂 Why Does This Matter?

In cleft palate patients, the closure mechanism is often compromised.
Depending on the severity of clefting, surgical correction aims to restore muscle positioning and improve velopharyngeal function.

Velopharyngeal Insufficiency (VPI) vs. Velopharyngeal Incompetence (VPC)


Velopharyngeal dysfunction (VPD) is an umbrella term for abnormal nasal airflow during speech, leading to hypernasality and articulation issues. It can be categorized into:

Velopharyngeal Insufficiency (VPI) – A structural problem where the velopharyngeal port cannot close properly due to an anatomical defect.
Velopharyngeal Incompetence (VPC) – A neuromuscular issue where the structures are intact, but they fail to function properly due to neurological conditions.

📌 Velopharyngeal Insufficiency (VPI): Structural Roadblock

Common Causes:
✅ Cleft Palate (Overt/Submucosal) – The levator veli palatini is abnormally positioned, preventing proper closure.
✅ Short Velum Post-Surgery – Even after palatoplasty, the velum may remain too short for complete closure.
✅ Oronasal Fistula – An opening between the mouth and nose, disrupting normal airflow.
✅ Adenoidectomy – Removal of enlarged adenoids can create an enlarged pharyngeal space, causing temporary or permanent VPI.

📌 Velopharyngeal Incompetence (VPC): A Functional Deficit

Common Causes:
✅ Congenital Hypotonia (e.g., Down syndrome, DiGeorge syndrome) – Weak muscle tone in the velopharynx.
✅ Neurological Disorders (e.g., traumatic brain injury, stroke) – Impaired neuromuscular control.
✅ Cerebrovascular Accidents (Stroke) – Disrupted nerve signaling affecting velopharyngeal movement.

📍 Key Difference?

VPI is a structural defect, while VPC is a neurological issue affecting muscle coordination.

🧬 Genetic Associations of Velopharyngeal
Incompetence

Picture this: a tiny segment of Chromosome 22 decides to disappear during DNA replication. Poof! Gone. As a result, a whole range of issues can pop up, including congenital heart defects, immune deficiencies, and—our star of the show—velopharyngeal incompetence (VPI).

VPI is when the velopharyngeal mechanism (aka the soft palate and surrounding muscles) doesn’t close properly, leading to speech that sounds like someone left the nasal door wide open. It’s like your voice is on a permanent speakerphone setting with no mute button.

Speech & The Great Escape: What’s Happening in VPI?
So, why does VPI happen in 22q11.2 deletions? Well, the list is long and full of bizarre anatomical quirks:

Muscle Hypotonia: The velopharyngeal muscles are basically slacking off, leading to poor closure. Lazy much?

Adenoid Hypoplasia: The adenoids are underdeveloped, so they don’t help with closure either.

Platybasia: A fancy term for a flattened skull base, which increases the velopharyngeal gap—kind of like trying to close a door in a frame that’s too wide.

Upper Airway Asymmetry: The palate lifts unevenly, like a seesaw with one side stuck.

Brain Involvement: Studies suggest even the brain structure is different in these individuals—because why should only the throat have all the fun?

The 22q11.2 Speech Struggle
A whopping 69% of individuals with 22q11.2 deletion have a palatal abnormality, ranging from cleft palates to bifid uvulas (which sounds like a cool sci-fi term but is just a split uvula). And 27% develop VPI, making speech therapy a must.

In a nutshell, VPI in 22q11.2 deletion syndrome isn’t just about anatomy—it’s a whole-body mystery that involves muscles, bones, and even the brain. If genes could talk, they’d probably just say, “Oops, my bad.”

So, next time you hear someone with a nasal voice, just know—it might be their genetics doing a disappearing act. Chromosome 22, you mischievous little trickster!

🧬 Candidate Genes for VPI: TBX1 and Beyond

Meet the Usual Suspect: TBX1

If VPI had a prime suspect, it would be TBX1. This little troublemaker is the most commonly deleted gene in 85% of individuals with 22q11.2 deletion syndrome. The other 15%? They like to keep things interesting with “nested deletions” (which is geneticist-speak for plot twists).

But here’s where it gets wild—some patients who don’t have the typical 22q11.2 deletion are rocking extra copies of the region that’s normally missing. That’s right—genetics sometimes decides to duplicate instead of delete, just to keep researchers on their toes.

TBX1: The Gene with a Plan (Sort of…)
Most of what we know about TBX1 comes from mouse studies. And let me tell you, these mice have been through a lot in the name of science. Researchers have been doing gene targeting experiments, and the results are basically a craniofacial nightmare:

Persistent truncus arteriosus (a heart defect that sounds like a spell from Harry Potter)
Microtia (tiny or missing ears)
Pharyngeal abnormalities (aka, VPI’s favorite excuse)
TBX1 is a transcription factor, meaning it bosses around other genes during development. It’s supposed to help form facial muscles, pharyngeal structures, and the palate, but when it goes missing, everything gets thrown into chaos—kind of like when a group project loses its most responsible member.

TBX1 and Its Entourage

But TBX1 doesn’t work alone—it’s got a whole squad of genes working (or not working) alongside it. Let’s meet the supporting cast:

ISL1 & Tcf21: These guys team up with TBX1 in the pharyngeal mesoderm (a fancy way of saying “throat muscle HQ”).
Six1 & Eya1: These two interact with TBX1 to make sure the fibroblast growth factor 8 (Fgf8) does its job. If Fgf8 isn’t happy, craniofacial development takes a serious hit.
Fgf8: The real MVP of face-building. Without enough Fgf8, the velopharyngeal region doesn’t form properly—resulting in speech and swallowing issues.
Basically, if TBX1 is missing, its whole gene friend group gets thrown into disarray. And when the genes aren’t cooperating, the palate and throat muscles end up looking like a half-finished jigsaw puzzle.

If you ever feel like your velum just isn’t pulling its weight, don’t be too hard on it—it’s probably dealing with a genetic crisis. Between TBX1 and its dysfunctional genetic friend group, the whole system is one big, messy group chat of developmental confusion.

On the bright side, research into these genes is ongoing, and the more we understand their roles, the better we can develop treatments for VPI and related conditions.

Until then, let’s just appreciate the genetic drama happening inside every developing face—because, let’s be honest, biology is just reality TV at a microscopic level.

BMP Signaling & Chordin: The Classic Good Cop, Bad Cop Duo
Bone morphogenetic protein (BMP) is that enthusiastic construction worker making sure your craniofacial structures develop. But if BMP isn’t kept in check, things can go overboard, and suddenly, we’re looking at craniofacial anomalies instead of a well-formed palate.

Enter Chordin, the BMP antagonist (aka The Enforcer). Chordin’s job is to keep BMP under control, but when Chordin takes an unexpected vacation (aka a genetic mutation), BMP gets out of hand. The result? Cleft palates, jaw abnormalities, and a whole lot of orthodontic intervention.

And guess what? TBX1, our favorite gene from the 22q11.2 deletion syndrome, is also involved. It turns out that if you mess up both TBX1 and Chordin, the craniofacial drama doubles. Think of it as trying to bake a cake but forgetting both the eggs and the flour. Not a great outcome.

IRF6: The Gene That Decided Your Lips Needed Extra Pits
Meet Interferon Regulatory Factor 6 (IRF6)—a gene that, when working correctly, helps your palate form properly. But when IRF6 goes rogue, it gives us Van Der Woude Syndrome (VWS), an autosomal dominant disorder responsible for cleft lip and palate… and surprise! Lip pits.

Yes, you heard that right. This gene doesn’t just cause cleft palates; it also throws in congenital pits or sinuses on the lower lip—because apparently, it thought your face needed extra pockets. Fun fact: This syndrome makes up about 2% of all cleft lip and palate cases. So if your lower lip has mysterious little dimples, you might just be rocking a genetic signature!

MSX1: The Overachiever Who Forgot to Finish the Job
Msh homeobox 1 (MSX1) is like that one student in class who almost gets full marks but forgets to answer the last question. MSX1 is critical for palatal formation and tooth development, but if it’s mutated, it causes cleft palate and oligodontia (fancy word for missing teeth).

Scientists studied MSX1-deficient mice (because mice always get roped into these things), and their palatal shelves formed, elevated… and then just didn’t fuse. It’s like the gene started the job and then took an extended coffee break. The exact reason? Still a mystery, but it seems related to down-regulated BMP signaling (back to BMP being the root of all trouble).

PVRL1: The Margarita Island Mystery Mutation
Ah, PVRL1, the gene with a backstory straight out of a medical mystery novel. Found on chromosome 11q23.3, this gene is responsible for keeping epithelial and endothelial cells nice and tight—kind of like the glue in your tissues. But when a mutation occurs? Say hello to ectodermal dysplasia Margarita Island type.

This autosomal recessive disorder is named after Margarita Island (off the coast of Venezuela), where there’s a surprisingly high number of people carrying this gene mutation. Affected individuals have cleft lip/palate, ectodermal dysplasia, and partial syndactyly (a.k.a. webbed fingers and toes).

Why is this mutation so common there? Scientists think it might have provided resistance to herpes simplex virus 1 & 2. So, while these folks may have had some serious craniofacial anomalies, at least they were better protected from cold sores. Genetics is wild.

If craniofacial development were a group project, TBX1, IRF6, MSX1, PVRL1, BMP, and Chordin would all be on the team. But, as we all know, in every group project:

One person (BMP) does way too much and messes everything up.
Another (Chordin) tries to control the chaos but can’t keep up.
One (MSX1) almost finishes but forgets the final step.
Another (PVRL1) makes a random decision no one saw coming.
And TBX1? Well, TBX1 just disappears half the time.
So, if your palate is perfectly formed—congrats! Your genetic group project actually turned out well. But if not… just blame your ancestors.

Anterior Maxillary Distraction by Tooth-Borne Palatal Distractor

Let’s talk about anterior maxillary osteotomy—a fancy way of saying “pushing your upper jaw back into place because your teeth decided to go rogue.” Now, before we dive into the nitty-gritty, let’s acknowledge the real heroes here: the orthodontists and surgeons who spend their days nudging bones like a very sophisticated game of Jenga.

Maxillary osteotomies have been around longer than your grandma’s secret recipe for laddoos. But unlike her kitchen skills, these techniques come with scalpels, screws, and a significant chance of making your nose twitch for weeks.

We have three classic moves in the Maxillary Osteotomy Dance:

1. Wassmund osteotomy – Named after a guy who probably spent too much time thinking about cutting bones.


2. Wunderer osteotomy – Wunderer…because wondering if your face will move correctly afterward is part of the thrill.


3. Anterior maxillary downfracture osteotomy – For those who like their surgery with a side of gravity.

While all three techniques get the job done, they differ in their “access route”, like Google Maps giving you three ways to get to the same dental conference—one scenic, one straightforward, and one with a questionable dirt road.

The Problem With Pushing Forward

Now, if you thought moving the anterior maxilla forward was easy, think again. The palatal mucosa is like an overprotective mother—it does not stretch easily. If you try too hard, you might end up with an oronasal or oroantral fistula. (For those unfamiliar, that’s a fancy way of saying, “Congratulations, you now have an accidental bonus airway!”)

In fact, the only reported case of maxillary advancement via osteotomy happened in 1968—shoutout to William Bell, the original maxillary daredevil. He moved the maxilla forward, bone-grafted the leftover gap, and then—because 1968 was a wild time—popped in a removable denture like a dental Band-Aid.

Enter Distraction Osteogenesis – The Slow and Steady Approach

The dental world eventually realized that gradual movement is the way to go (kind of like convincing your cat to take a bath). So, we borrowed a trick from orthopedics: distraction osteogenesis. Originally developed for cleft lip and palate cases, this technique slowly moves bones using:

External distractors – Big, bulky, and very “Mad Max.”

Orthodontic face masks – Like Invisalign’s overachieving cousin.

Internal distractors – The discreet VIP section of distraction devices.


But here’s the twist: these are mostly used to move the whole maxilla forward (Le Fort I style), rather than just the anterior segment. That’s like moving an entire apartment building when all you really needed was to shift the balcony.

The Unexpected Hero: The Palatal Distractor

Palatal distractors have traditionally been used for expansion, helping kids (and the occasional brave adult) widen their maxilla to correct collapsed buccal occlusion. But someone (probably while holding a coffee and staring at a dog study) thought, “Hey, what if we used this thing to move the maxilla forward?”

The results?

Tooth-borne distractors were tested on dogs (lucky them), and they did successfully move the anterior maxilla forward—along with a lot of dental movement.

Bone-borne distractors came in to save the day, ensuring that actual bone (not just teeth) was being moved.

And guess what? There’s exactly ONE reported case of a palatal distractor being used to advance a retruded maxilla in a non-cleft patient. Just one. That’s rarer than an orthodontist who doesn’t own at least three pairs of loupes.

Who Needs This? (Besides People Who Want to Look Like Their Own X-Ray)

This technique is perfect for patients with maxillary hypoplasia in both the anteroposterior and transverse planes—especially if they have cleft lip and palate. Think of it like a strategic battlefield move:

Crossbite limited to anterior and premolars? Check.

Molars behaving themselves in normal buccal occlusion? Check.

Dental crowding making your orthodontist sigh dramatically? Check.


The beauty of this approach? As your maxilla gradually advances, new bone forms in its wake—meaning your displaced teeth can be politely guided into their new positions with post-surgical orthodontics.

The Surgical Game Plan: Step-by-Step (or Slice-by-Slice)

Step 1: Build Your Secret Weapon – The Hyrax Appliance

Before the surgery even starts, we need our mechanical hero: the Hyrax orthodontic appliance (which sounds like a prehistoric creature but is actually a German-made expansion screw). Unlike its usual role in expanding palates sideways, we tweak it to push forward instead of out.

4 arms of the appliance:

2 anterior arms → Soldered to canines or first premolars

2 posterior arms → Soldered to first or second molars

This is the equivalent of securing a medieval battering ram before storming the castle walls.

Step 2: Knock Knock, It’s Surgery Time!

Under general anesthesia (because no one wants to be awake for this), we begin:

1. Vestibular incision – From first molar to first molar (basically, a wide front door for the maxilla).

2. Mucoperiosteal flap reflection – Peeling back the gums like opening a well-wrapped gift… but with scalpels.

3. Buccal linear osteotomy – A clean cut above the maxillary teeth from pyriform rim to distraction site.

4. Lateral nasal wall cut – Because your nose needs to be in on the action too.

5. Septal osteotomy – The nasal septum gets a trim at its base (like a very aggressive haircut).

At this point, your maxilla is thinking, “What did I do to deserve this?”

Step 3: The Grand Downfracture (Because Upfracturing Isn’t a Thing)

Vertical interdental osteotomy → First, a light cut through the buccal cortex, then deepened carefully (like slicing a layered cake).

Palatal osteotomy → Extending the cut medially to separate the segment without puncturing the palatal mucosa (because who needs a hole in their mouth?).

Downfracturing the anterior maxilla → A gentle wiggle and push to mobilize it forward (think of convincing a cat to move off your laptop).

Important Rule: Do not mess with the palatal mucosal pedicle—it’s keeping everything alive!

Step 4: Installing the Hyrax & Hitting the Snooze Button

1. Cement the appliance onto the selected teeth. (Your maxilla is now officially in a mechanical relationship.)

2. Close the surgical wound. (Because we don’t want to leave things open-ended.)

3. Let the bone chill for five days. (Surgery is tiring. Even for your face.)

Step 5: The Big Move – Slow & Steady Wins the Maxilla Race

On post-op day five, we start activating the Hyrax:

1mm per day (Because bones like to take their time).

2 to 4 activation rhythms per day (Like an orthodontic drumbeat).

The anterior maxilla keeps moving forward until a normal overjet is achieved.

Once it’s in place? Lock it in for 6 weeks—because good things take time (and so does new bone formation).

The Good, The Bad & The Orthodontist Who Has to Deal With It

✅ The Benefits:

⭐ No need for bone grafts – Your body does all the hard work.
⭐ Improved soft tissue support – Upper lip & paranasal area get a free upgrade.
⭐ Better space for orthodontic alignment – Less need for tooth extractions.
⭐ Stability – Unlike nonvascularized bone grafts, this bone won’t shrink over time.

⚠️ The Potential Drama:

🚨 Anchorage issues – If the patient lacks premolars/molars, the posterior teeth might move instead of the maxilla.
🚨 Tooth proclination – If the palatal osteotomy isn’t done properly, the front teeth might tip forward instead.
🚨 Appliance limitations – Tooth-borne distractors provide great control, but bone-borne devices might be more stable.

Long-term Follow-up After Maxillary Distraction Osteogenesis in Growing Children With Cleft Lip and Palate

If bones could talk, they’d probably say, “Hey, stop pulling me!” But in the world of distraction osteogenesis (DO), that’s exactly what we do—intentionally stretch bone tissue to create new growth. Think of it as the orthodontic equivalent of a yoga instructor telling your jaw to lengthen and breathe.

While orthognathic surgery has been the gold standard for skeletal corrections, DO has stepped in as the cool new kid, especially for cases that were once deemed untreatable. But is it really the superior method, or just a fancier way to move bones? Let’s break it down.

Since its first craniofacial application by McCarthy et al. in 1992, DO has come a long way from being an experimental idea to a widely used technique for maxillary and mandibular expansion. But, like any orthodontic superhero, it comes with its strengths, weaknesses, and a history of trial-and-error that reads like a medical thriller.

The Origins: From Soviet Leg Braces to Jawline Makeovers

DO owes its roots (pun intended) to Ilizarov’s principles—a Russian orthopedic surgeon who figured out that bone can be stretched and tricked into regenerating. What started as a method for limb lengthening soon found its way into orthodontics when McCarthy et al. used it to lengthen hypoplastic mandibles in children.

Once researchers saw potential in midface and maxillary distraction, it became a game-changer for patients with clefts and severe maxillary hypoplasia—especially when traditional orthognathic surgery wasn’t an ideal option.

With miniature distraction devicesrigid external distraction (RED) systems, and intraoral appliances, the orthodontic world saw an explosion (well, controlled expansion) of techniques:

🔹 Cohen et al. (1997) – Introduced maxillary distraction in young children.
🔹 Polley & Figueroa (1997) – Used the RED device to treat severe maxillary hypoplasia.
🔹 Molina et al. (1998) – Tried a mix of facial masks and intraoral appliances for mixed dentition cases.

So, Does It Work? The Numbers Speak!

Swennen et al. (2001) reviewed 16 studies spanning 33 years (1966-1999) and found that maxillary advancements ranged from 1 mm to 17 mm. Not bad for a non-surgical approach, right?

Well, not so fast—relapse was reported in 50.4% of cases. That’s like getting a six-pack after months of workouts only for it to disappear when you eat one slice of pizza.

Rachmiel et al. (2005) reported stable results in 12 cleft patients after two years, showing that maxillary length (Condylion to A point) held its ground. But Krimmel et al. (2005) later threw a wrench into that optimism, noting a decrease in SNA and ANB angles just one year after distraction.

Cheung & Chua (2006) conducted a meta-analysis of 26 studies (1966-2003) on 276 cleft patients, revealing:

📌 Most maxillary advancements were between 5-9 mm.
📌 External distractors (68.8%) were more common than internal distractors (2.17%) and facial masks (25.72%).
📌 Maxillary relapse? 5.56% within two years—but only one study provided actual numbers.

One thing is clear: distraction osteogenesis works, but long-term stability is still a mixed bag.

The Study: Six Patients, One Mission—Expand That Maxilla!

Meet our VIPs: six Chinese patients (3 boys, 3 girls, average age 10.5 years), all of whom had:
✔ Cleft lip and palate (two unilateral, four bilateral)
✔ Primary lip and palate repair in infancy
✔ Anteroposterior maxillary hypoplasia (aka, their upper jaw was slacking)
✔ Class III malocclusion with a negative overjet (translation: their lower teeth were winning a battle they shouldn’t even be fighting)

These kids weren’t just getting braces—they were about to experience controlled bone expansion, courtesy of the Rigid External Distraction (RED) device.

1️⃣ Pre-Orthodontic Preparation – Because even bone stretching needs a good warm-up.
2️⃣ Complete High Le Fort I Osteotomy – A fancy way of saying, “Let’s surgically cut the upper jaw so we can move it.” where the maxilla was delicately detached with septal and pterygomaxillary disjunction. (Translation: we made it mobile but still attached—think of it as unlocking a door, not knocking it down.)
3️⃣ RED Device Installation – Think of this as the orthodontic version of a headgear, but instead of just pushing teeth, it’s stretching the entire upper jaw.
4️⃣ Latency Period (5 Days) – Let the jaw marinate before we start stretching it.
5️⃣ Active Distraction (1 mm/day) – The screws on the RED device were adjusted daily to pull the maxilla forward. (It’s like a gym for your bones—except you don’t have to do the work; your jaw does.)
6️⃣ Overcorrection Achieved! 🎉 – Because we know relapse is real, we stretched the maxilla a little extra to compensate for future setbacks.
7️⃣ Consolidation (6-8 Weeks) – The RED device stayed put to let the new bone solidify.
8️⃣ Device Removal & Orthodontics – After the expansion was done, the real party started: braces to fine-tune everything.

The study wasn’t just about making kids look less Class III—it was about proving that DO actually works (and hopefully, stays that way). Here’s how they did it:

📸 Lateral Cephalographs  were taken at four key points:
🔹 T0 (Before Distraction) – “This is your jaw on cleft-induced hypoplasia.”
🔹 T1 (Immediately After Distraction) – “Congratulations, your maxilla has entered the chat.”
🔹 T2 (6 Months Later) – “Let’s see if your jaw likes its new position.”
🔹 T3 (1+ Year Later) – “Did it stay put, or did it sneak back?”

Instead of using simple before-and-after pictures (this isn’t a weight loss commercial), the researchers mapped out skeletal and dental landmark positions using a cranial base reference system.

How, you ask?

🔹 First, skeletal landmarks were pinpointed on the T0 cephalogram.
🔹 Then, these landmarks were transferred onto T1, T2, and T3 cephalograms using a best-fit method—aligning surrounding bone structures and trabecular patterns (Huang & Ross, 1982).
🔹 To keep things precise, an x-y coordinate system was created:

Y-axis: A perpendicular line intersecting the X-axis at sella
🔹 This coordinate system was then transferred onto each cephalogram for standardized measurements.

X-axis: Drawn 7° below the sella-nasion plane

Key Takeaways

✅ Overjet increased (yay, no more Class III woes!).
✅ Overbite decreased—except for our rebellious Case 5.
✅ Maxilla went forward (woo-hoo!) but then took a casual retreat backward over a year (boo!).
✅ Some vertical movement—first up, then down (the maxilla, not our enthusiasm).
✅ Teeth tagged along for the ride, moving anteriorly and inferiorly.
✅ Relapse? Oh yeah—about 9.6% at 6 months, increasing to 24.5% by a year.

Evaluation of the Jones jig appliance for distal molar movement

What is the Jones Jig Appliance?

Orthodontic treatment often requires space creation to align teeth properly. One effective way to achieve this is through molar distalization—moving the upper first molars backward to make room for crowding or to correct bite discrepancies. Traditionally, orthodontists have relied on headgear, Class II elastics, and removable appliances, all of which require patient compliance (and we all know how reliable that is! 🙄).

But what if there was a more predictable, fixed alternative?

Enter the Jones Jig Appliance—a fixed, non-compliance-based distalizing appliance designed to move molars efficiently without relying on patient effort.

How Does the Jones Jig Work?

✔ Palatal Button – A 0.5-inch diameter acrylic button, anchored to the maxillary second premolars using a 0.036-inch stainless steel wire for stability.
✔ Jones Jig Arms – One arm fits into the 0.045-inch headgear tube, while the other fits into the slot of the first molar band.
✔ Nickel-Titanium Spring – A 0.040-inch coil spring delivers a controlled force of 70-75 g to push the molars backward.

Once the Jones Jig is cemented, it is activated by tying the activation loop with a 0.010-inch ligature off the bracket of the anchoring tooth. This ensures continuous force application.

The coils are then reactivated every 4 to 5 weeks until the desired molar movement is achieved.

Once activated, the appliance applies a gentle but continuous distal force on the upper first molars, moving them backward over time. The best part? Since it’s fixed, patients don’t have to remember to wear it, making treatment more reliable.

Advantages of the Jones Jig

✅ No Patient Compliance Needed – Unlike headgear, patients don’t have to wear or adjust it.
✅ Continuous Force Application – The coil spring ensures a steady force for predictable movement.
✅ Faster Treatment Time – Studies show that molars can be distalized in 4-6 months.

While the Jones Jig is highly effective, it does come with some considerations:
🔹 Molar Tipping – Instead of bodily movement, molars may tip distally, requiring additional mechanics for uprighting.
🔹 Anchorage Loss – The anterior teeth may shift forward slightly, which may need to be controlled with TADs (temporary anchorage devices) or a transpalatal arch (TPA).

Does the Eruption of Second Molars Affect Treatment?

When using the Jones Jig Appliance for molar distalization, orthodontists must consider various factors that can influence treatment outcomes. One key question is: Does the eruption of second molars impact molar movement and anchorage loss?

A study evaluating 72 patients explored this question by comparing cases with erupted vs. unerupted maxillary second molars to determine how they affected the type and amount of molar movement and anchorage loss.

Study Findings: Second Molar Eruption and Its Effects

Researchers divided the patients into two groups:

GroupCondition of Second MolarsKey Observations
Group 1 (28 patients)Unerupted second molars (below the cementoenamel junction of the first molar)Less anchorage loss in premolars and incisors, potentially more controlled molar movement.
Group 2 (44 patients)Erupted second molars (not banded or bonded)More anchorage loss observed, possibly due to resistance from the second molars.

The presence or absence of second molars plays a significant role in the effectiveness of molar distalization. Patients with unerupted second molars may experience better molar movement with less anchorage loss, while those with erupted second molars may require additional anchorage support. In cases with erupted second molars, additional anchorage reinforcement (e.g., TADs or a transpalatal arch) may be necessary to prevent undesired movement.

Study Findings: How Far Did Those Molars Go?

retrospective study of 72 patients using the Jones Jig showed:

Tooth MovementMean ChangeTipping AngleComparison to Other Appliances
Maxillary First Molar2.51 mm distal movement7.53° distal tipping
(meaning they didn’t just move—they leaned back like someone dodging responsibility. 😅)
Similar to Herbst, Wilson Mechanics, and Pendulum Appliance 📏
Maxillary Second Molar1.79 mm distal movement
(Not as much as the first molar, but still making progress! 🔄)
8.03° distal tipping
(tipped even more than first molars)
0.71 mm extrusion observed 📉
(suggests that second molars are like that one friend who always stands out in group photos. 📸)
OverjetIncreased 0.45 mm

If necessary, J-hook headgear or Class II elastics can help maintain anchorage.
2.21° incisor proclination

(much less than the 6° seen in other studies. So, while there’s some flaring, it’s not enough to make your patient look like Bugs Bunny. 🐰)
Less flaring than with Pendulum & Repelling Magnets 😎

Less than the 1.30 mm increase seen with the Pendulum appliance and the 1.60 mm increase with repelling magnets.
OverbiteDecreased 1.28 mmImproved vertical control compared to other appliances 📊

Anchorage Control: Because We Don’t Want Molar Tipping Running the Show

Distalizing molars is great, but uncontrolled tipping? Not so much. Here’s where anchorage control steps in like a responsible chaperone at a high school dance.

✅ Use a Nance holding arch, utility archwire, or stopped archwire to keep those molars in check.
✅ Short Class II elastics can help move the premolars and incisors back once the molars are in position.
✅ J-hook headgear can reinforce anchorage (for the brave souls who still prescribe it).

Molar Extrusion: Is It a Big Deal?

One concern with distalization is molar extrusion—but does the Jones Jig make teeth “float away”? Not really.

🔹 Jones Jig Patients:

  • Males: 3.17 ± 1.79 mm of extrusion
  • Females: 1.33 ± 1.38 mm of extrusion

🔹 Untreated Class I Patients (for comparison):

  • Males: 4.1 ± 3.1 mm
  • Females: 1.9 ± 2.2 mm

📌 Takeaway?
The extrusion in Jones Jig patients is within normal growth changes. So, unless your patient is trying to float their molars into the stratosphere, this isn’t a major concern. 🚀

Jones Jig vs. Headgear: Any Real Difference?

The study found no statistically significant differences between the Jones Jig group and a matched Headgear groupwhen evaluating:

✅ Maxillary first molar position
✅ Maxillary central incisor angulation
✅ Linear position of incisors
✅ Overjet & Overbite changes

So, if you’re an orthodontist who loves avoiding unnecessary patient lectures about compliance, the Jones Jig might be your new best friend. 🎉

Treatment Comparison: Who Wins?

Treatment ModalityPatient Compliance Needed?Molar Distalization (mm)Overjet Change (mm)Overbite Change (mm)
Jones Jig Appliance❌ No compliance needed2.51 mm+0.45 mm-1.28 mm
Cervical Headgear✅ Requires compliance 😬2.50 mm+0.40 mm-1.30 mm
Class II Elastics✅ Requires compliance 🙄Varies (depends on use)Greater risk of overjet increaseLess predictable molar control

📌 Takeaway?
The Jones Jig does everything headgear does—without the compliance drama. It’s like getting straight A’s without ever studying (if only life worked that way 😆).

Final Verdict: Is the Jones Jig Worth It?

✔ YES! If you want a fixed, predictable, non-compliance-dependent way to correct Class II malocclusions, the Jones Jig is a great choice.

✔ Same results as headgear—without the teenage rebellion.

✔ Minimal anchorage loss compared to other distalization appliances (no crazy overjet increase).

✔ Less annoying for patients = less annoying for you. 😆

Unilateral face-bows: A theoretical and laboratory analysis

Orthodontics has long relied on mechanical devices to refine tooth movement and optimize jaw alignment. Among these, the face-bow remains an essential tool for controlled force application. Recent experimental and theoretical studies have focused on enhancing face-bow designs to achieve unilateral distal forces more efficiently. This post synthesizes key findings regarding the efficacy of various face-bow configurations, addressing their theoretical underpinnings and practical implications for advanced orthodontic care.

Comparative Analysis of Face-Bow Designs

Face-Bow TypeKey FeaturesForce DistributionResulting Forces
Swivel-Offset Face-Bow– Outer bow attached eccentrically via a swivel joint.- Allows lateral movement of the outer-bow tips.– Unequal force distribution.- Delivers unilateral distal forces.- Generates lateral forces.– Delivers unilateral force with predictable lateral forces.- Effective for asymmetric treatment.
Symmetrical Face-Bow– Outer bow symmetrically aligned.- Balanced force application.– Even force distribution on both sides.- No lateral force generated.- Ineffective for unilateral force delivery.– No unilateral or lateral forces delivered.
Soldered-Offset Face-Bow– Rigid attachment of outer bow on one side.- Appears asymmetrical but does not deliver unilateral forces.– Symmetrical force distribution.- No lateral force generated.– No unilateral force delivered.
Spring-Attachment Face-Bow– Spring on one terminal of the inner bow.- Symmetrical outer-bow tips.– Equal force on both sides.- No lateral force generated.– No unilateral force delivered.

Which Face-Bow Designs Effectively Deliver Unilateral Distal Forces?

Not all face-bow designs are capable of delivering sufficient unilateral distal forces, an essential factor for treating conditions such as unilateral posterior crossbites or asymmetrical dental arch development. The following analysis highlights the effectiveness of different face-bow configurations:

  • Ineffective Designs:
    • Bilaterally Symmetrical Face-Bows: These designs maintain equal force distribution on both sides, making them unsuitable for unilateral force application.
    • Spring-Attachment Face-Bows: Despite their versatility, these face-bows fail to concentrate force on a single side, limiting their application in unilateral treatments.
    • Soldered-Offset Face-Bows: While superficially asymmetrical, the rigid attachment of the outer bow does not result in the necessary unilateral force distribution.
    These designs consistently failed to generate a mean unilateral distal force exceeding 60%, thereby limiting their clinical utility for unilateral orthodontic applications.
  • Effective Designs:
    • Power-Arm Face-Bows: These designs effectively direct unilateral forces, achieving greater than 60% of the force distribution to one side, which aligns with clinical requirements for unilateral force application.
    • Swivel-Offset Face-Bows: By incorporating a swivel mechanism, these face-bows create asymmetry, allowing for targeted distal force delivery to one side.

Both of these designs surpass the 60% threshold for unilateral force distribution, thus meeting the criteria for effective treatment.

Theoretical Framework for Unilateral Force Delivery

The key to effective unilateral force application lies in the asymmetry of the face-bow’s design. When the outer-bow tips are positioned asymmetrically relative to the midsagittal plane of the inner bow, it allows for the focused application of force on one side:

  • Asymmetrical Designs: These designs facilitate targeted force delivery by creating a mechanical advantage that directs the force to one side. This results in the efficient application of unilateral distal forces, which is essential for treating asymmetric dental and skeletal issues.
  • Symmetrical Designs: These configurations fail to produce unilateral forces because the force is evenly distributed, thus making them ineffective for unilateral applications.

The swivel-offset face-bow achieves this asymmetry through a lateral swing of the outer-bow terminals, while power-arm face-bows, when constructed with comparable geometric patterns, similarly exhibit the necessary force distribution for unilateral applications.

Characterization of Lateral Forces in Unilateral Face-Bows

Unilateral face-bows not only generate distal forces but also produce lateral forces that contribute to the overall mechanical effect. These lateral forces are characterized by the following:

  • Directionality: The lateral force is directed from the side receiving the greater distal force toward the opposite side, ensuring balanced correction of dental and skeletal asymmetries.
  • Magnitude: The magnitude of the lateral force increases with the unilateral effectiveness of the face-bow, making it a predictable variable in effective designs.
  • Predictability: Experimental studies demonstrate that lateral forces are highly predictable in effective designs, such as the power-arm and swivel-offset face-bows, whereas they are erratic and difficult to control in symmetrical, ineffective designs.

Practical Considerations for Clinicians: Which Face-Bow Design is Optimal?

While both the power-arm and swivel-offset face-bows are effective in delivering unilateral distal forces, the power-arm design stands out in terms of practicality and clinical efficiency:

  • Ease of Fabrication: The power-arm face-bow can be easily modified chairside from a conventional face-bow, offering flexibility and reduced chair time for both clinicians and patients.
  • Predictable Performance: Experimental data show that the power-arm design provides a force distribution that closely matches that of the swivel-offset face-bow, with less than a 5% difference in performance.
  • Patient Comfort: The power-arm design ensures more consistent force application, contributing to better patient comfort and compliance during treatment.

Effects of cervical headgear appliance: A Guide for Orthodontic Students

Treating Class II malocclusion can be a challenging endeavor due to the diverse range of appliances available and the complexity of dental and skeletal relationships between the maxilla and mandible. To simplify the analysis and ensure consistent outcomes, studies focusing exclusively on cervical headgear have provided valuable insights.

Why Cervical Headgear?

Cervical headgear is like the Swiss Army knife of Class II malocclusion treatment. Its efficacy, however, depends significantly on when you start using it. Research suggests that the late mixed dentition or the onset of permanent dentition is the orthodontic equivalent of “prime time.” With a force of 450 to 500 grams on each side—basically the weight of a small apple—the appliance works best when worn for 12 to 14 hours daily. Yes, that’s half a day, so patients need to be as committed as a coffee addict to their morning brew.

Effects of Cervical Headgear on Molar Position and Bite

One notable effect observed in studies is the extrusion of maxillary first molars, a phenomenon first described in the 1970s. Think of it as the molars getting a little too excited and rising up—like bread dough, but less tasty. This leads to bite opening and an increase in vertical parameters, which can be a problem for dolichofacial patients with long faces. Adding height to an already tall face is like putting a top hat on a giraffe—probably not the best idea. However, with careful management, even vertical growers can benefit from this appliance.

Mandibular Rotation and Vertical Changes

Molar extrusion also causes mandibular clockwise rotation, leading to an increase in the mandibular plane angle. This backward rotation is well-documented, and while it’s not ideal, it’s not the end of the world either. After all, even the best orthodontic plans can sometimes feel like trying to herd cats—challenging but ultimately rewarding.

Arch Expansion and Alignment

Cervical headgear also moonlights as a gentle expander of the upper arch, introducing an 8 to 10 mm expansion in the inner bow. This expansion helps align maxillary teeth and the mandibular arch to follow suit. It’s like getting a BOGO deal on alignment—who doesn’t love that? These changes create excellent conditions for the mandible to grow to its full potential, making Class II correction a reality.

Maxillary Repositioning and Overjet Correction

Another party trick of cervical headgear is improving the maxillomandibular relationship. By restricting forward and downward maxillary displacement, it lets the mandible grow normally, compensating for the initial overjet. It’s like giving the mandible a chance to shine on the orthodontic stage—finally, the underdog gets its moment.

Key Takeaways for Orthodontic Students

  • Timing Matters: Initiate treatment during late mixed dentition or early permanent dentition for optimal results.
  • Patient Selection: Avoid using cervical headgear in dolichofacial patients with extreme vertical growth patterns.
  • Appliance Effects: Understand the implications of molar extrusion, mandibular rotation, and vertical parameter changes.
  • Comprehensive Benefits: Leverage the appliance’s ability to expand arches, improve alignment, and enhance the maxillomandibular relationship.

Cervical headgear remains a cornerstone in the treatment of Class II malocclusion. By mastering its application and understanding its effects, orthodontic students can achieve predictable and effective outcomes in their clinical practice.

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Speech and Malocclusion #Paper1

Introduction

Orthodontic care primarily focuses on dental esthetics and masticatory function, but its impact on sound production is often overlooked. Sound production involves a dynamic interaction with the oral cavity, requiring orthodontists to recognize how dental anomalies and treatments influence speech. Enhanced patient care can be achieved through better treatment planning and referrals to speech pathologists for patients whose malocclusions affect speech production. This is particularly relevant for adults requiring proper speech for professional purposes.

Definition of Sound and Speech Mechanism

Sound is mechanical vibration energy requiring the coordination of neural, muscular, mechanical, aerodynamic, acoustic, and visual elements. Speech production involves four processes:

  1. Language processing in the brain.
  2. Motor command generation to vocal organs.
  3. Articulatory movements of the oral cavity.
  4. Air emission from the lungs.

Speech sounds are classified into:

  • Vowels: Produced without obstruction to airflow.
  • Consonants: Produced with varying obstructions in oral or nasal cavities.

Classification

  • Ingram’s Classification:
    1. Dysphonia: Disorders of vocalization.
    2. Dysrhythmia: Respiratory coordination issues.
    3. Dysarthria:
      • Due to neurological abnormalities (e.g., motor neuron lesions).
      • Due to local abnormalities (e.g., jaws, teeth, palate).
    4. Non-Structural Disorders: Mental, hearing, or environmental factors.
    5. Developmental Disorders: Abnormal or delayed speech development.
    6. Mixed Disorders: Combination of the above.
  • Types of Consonants:
    • Bilabial consonants: “b”, “p”, “m”
    • Labiodental consonants: “f ”, “v”
    • Dental consonants: “d”, “t”, “n”, “s”, “z”
    • Dentoalveolar consonants: “c”, “c”, “j”, “ş”
    • Frontopalatal consonants: “g”, “k”, “l”, “r”, “y” 
    • Backpalatal consonants: “g”, “ğ”
    • Pharyngeal consonant: “h”
    • Nasal consonants: “m”, “n”

Orthodontic Implications

  • Malocclusion and Speech:
    • Class II Malocclusion:
      • Difficulty with bilabial sounds (“p,” “b,” “m”).
      • Compensatory mechanisms involve lower lip contacting maxillary incisors.
    • Class III Malocclusion:
      • Difficulty with labiodental sounds (“f,” “v”).
      • Common errors include bilabial production or reversed labiodental posture.
      • Dentalization leads to lisping for sounds like “t,” “d,” “s,” and “z.”
    • Open Bite:
      • Anterior lisping and distortion of anterior sounds.
      • Severe cases show more misarticulations when combined with other anomalies.
    • Diastema:
      • Impacts sounds like “l,” “n,” and “d.”
  • Velopharyngeal Dysfunction: Associated with cleft palate, causing hypernasal resonance and airflow issues.
  • Adaptation Mechanisms: Tongue and lips often adapt to dental irregularities, masking speech defects.

Studies

  • Fymbo’s Study:
    • Analyzed 410 students, noting a higher incidence of speech difficulties in those with malocclusion.
    • Severity of speech defects correlated with the severity of dental anomalies.
  • Laine et al.:
    • Narrower palates linked to sibilant speech disorders.
    • Increased open bite and overjet have greater impacts than spacing.
  • Dalston and Vig:
    • Minimal long-term speech changes post-orthognathic surgery.
  • Garber et al.:
    • Temporary speech errors observed post-surgery resolved within 1-3 months.

Shortcomings

  • Limited Longitudinal Data: Lack of extended studies tracking speech changes post-treatment.
  • Standardization Issues: No universal methods to measure malocclusion-related speech defects.
  • Complex Etiology:
    • Speech defects often result from multiple factors, not just malocclusion.
    • Adaptation varies based on intelligence, emotional state, and muscle control.

Understanding the Quad-Helix Appliance for Maxillary Expansion

Palatal expansion has been a cornerstone of orthodontic treatment for over a century. Despite its proven efficacy, this technique has sparked debates within the orthodontic community. Is rapid expansion the best approach, or do slower methods offer greater stability? Let’s dive into the history, mechanics, and clinical applications of maxillary expansion, with a special focus on the quad-helix appliance.

The primary goal of palatal expansion is to coordinate the maxillary and mandibular denture bases, addressing narrow or collapsed arches. This can be achieved through:

  1. Orthodontic Movement (tooth-focused)
  2. Orthopedic Movement (bone-focused)
  3. Combination Therapy

A variety of appliances—fixed, semi-fixed, and removable—are employed to achieve these goals.

MethodAdvantagesChallenges
Rapid Palatal ExpansionQuick skeletal changesPotential for relapse and sutural strain
Slow ExpansionGreater histologic integrity of suturesRequires longer treatment time

HISTORY

Coffin Loop Appliance:

  • Incorporated in a vulcanite plate for upper arch expansion.
  • Produces continuous force due to the configuration of the palatal compound loop.

Martin Schwarz Appliance:

  • Popular in Europe.
  • Utilizes tissue-borne anchorage with wire components for tooth movement.
  • Expansion force is intermittent due to the jackscrew mechanism.

Haas and Wertz Fixed Appliance:

  • Designed for rapid expansion of the midpalatal suture in narrow maxillary arches.
  • Cemented to maxillary first premolars and first permanent molars.
  • Includes a palatal jackscrew and acrylic extensions.
  • Produces lateral orthopedic movement of the maxilla due to high force magnitude.

Load-Activation Characteristics:

  • Chaconas and Caputo found differences in stress transmission through craniofacial bones with various fixed expansion appliances.
  • Impact on craniofacial sutures varies depending on the appliance.

Rickett’s “W” Expansion Appliance:

  • Initially used for cleft palate conditions with collapsed dental arches.
  • Acts continuously over time until activation force dissipates.

What Makes the Quad-Helix Appliance Unique?

Helical Loops for Increased Flexibility:

  • Initially added to the posterior segment of the palatal arch
  • Further modification introduced four loops (two anterior and two posterior), creating the quad-helix appliance.

Construction Details:

  • Made of 0.038-inch (0.975 mm) wire.
  • Soldered to bands cemented to maxillary first permanent molars or deciduous second molars, depending on the patient’s age.

Initial Activation and Effects:

  • Appliance is activated before cementation.
  • Results in expansion of buccal segments and rotation of banded teeth 

Force Magnitude:

  • Chaconas and Caputo reported that 8 mm of expansion before cementation generates approximately 14 ounces of force 

Effectiveness in Different Age Groups:

Effective in orthopedically widening the maxilla in children, helping to establish a normal maxillomandibular relationship.

Force is sufficient for tooth movement but insufficient for orthopedic effects in adults with closed midpalatal sutures.

In children, particularly in the deciduous or early mixed dentition stages, the resistance of the patent suture is lower than the dentoalveolar area.

Clinical Case: A Pediatric Success Story

  • Patient History: Prolonged thumb-sucking led to a narrow maxilla due to lowered tongue position and buccinator muscle forces.
  • Treatment: Quad-helix appliance activated ~8 mm, sufficient for maxillary expansion.
  • Outcome: Successful expansion and resolution of thumb-sucking habit. The appliance’s palatal position ensured comfort and minimal impact on speech.
AdvantagesImpact
Acts as a habit-breaking deviceAddresses prolonged thumb-sucking habits
Comfortable for the patientMinimal impact on speech
Effective in pediatric casesAchieves orthopedic widening of the maxilla

Insights from Cephalometric and Cast Analysis

Orthodontic Changes (T₁ to Tₚ)

  1. Maxillary Molar Width: Increased by an average of 5.88 mm, reflecting significant dental expansion.
  2. Average Frontal Molar Relation: Improved by 2.95 mm, indicating better occlusal alignment.
  3. Maxillary Intercanine Width: Expanded by 2.74 mm, enhancing anterior dental arch form.

Orthopedic Changes (T₁ to Tₚ)

  1. Maxillary Width: Increased by 0.92 mm, with five cases showing expansions exceeding 2.7 mm.
  2. Maxillomandibular Width: Increased by 0.89 mm, with notable cases surpassing 1.4 mm.
  3. Palatal Changes: The anterior palate moved downward, increasing maxillary height.

Relapse and Stability (Tₚ to T₂)

  1. Minimal Relapse: Dental expansions remained stable over 42 months.
  2. Orthopedic Effects: Demonstrated high stability, contrasting with the relapse often seen in rapid palatal expansion.
  3. Palatal Plane and Maxillary Height: Slight decreases observed, indicating no net parallel downward movement.

Slow vs. Rapid Expansion

  • Slow expansion using the quad-helix appliance demonstrated superior stability and less relapse compared to rapid palatal expansion. The gradual physiologic movement allowed the facial skeleton to adapt, ensuring long-term stability.

Bite Opening

  1. Active Expansion (T₁ to Tₚ): Slight bite opening occurred due to occlusal interferences.
  2. Post-Expansion (Tₚ to T₂): Additional bite opening was attributed to orthodontic treatment rather than the expansion appliance.

Facial Skeletal Considerations

  • Stability was influenced by initial nasal and maxillary widths:
    • Narrow Maxilla + Normal/Wide Nasal Width: High stability.
    • Narrow Nasal Width + Normal Maxilla: Lower stability.

Facial Type

  • The sample skewed toward brachyfacial types, limiting conclusions about expansion outcomes across facial types.

Effective Early Correction of Posterior Cross-Bites by Quad-Helix or Removable Appliances

Early Correction of Posterior Cross-Bites

  • Advocated to:
    • Direct erupting teeth into normal positions.
    • Eliminate premature occlusal contacts.
    • Promote beneficial dentoskeletal changes during growth periods (Bell, 1982).
  • Posterior cross-bites develop early and are not self-correcting (Moyers & Jay, 1959; Thilander et al., 1984).

Orthodontic Response to Expansion

  • Initial response completed within a week (Storey, 1973; Cotton, 1978; Hicks, 1978).
  • Subsequent movements occur as compressed buccal alveolar plate resorbs at the root-periodontal interface due to continued force (Storey, 1973).

Orthopaedic Effects of Expansion

  • Sufficient transverse forces can overcome bioelastic strength of sutural elements, causing:
    • Orthopaedic separation of maxillary segments (Storey, 1973; Chaconas & de Alba y Levy, 1977; Cotton, 1978; Hicks, 1978).
    • Palatal segment repositioning continues until force is reduced below sutural tensile strength.
  • Stabilization involves reorganization and remodeling of sutural connective and osseous tissues (Storey, 1973; Ekstrom et al., 1977).

Increased Maxillary Arch Width

  • Linked to orthodontic and/or orthopaedic effects of expansion (Ficarelli, 1978; Moyers, 1984).
  • Initial changes involve lateral tipping of posterior maxillary teeth due to compression and stretching of periodontal and palatal soft tissues.

Midpalatal Sutural Opening and Maxillary Displacement

  • Expansion leads to:
    • Downward and forward displacement of the maxilla with bite opening (Haas, 1961).
    • Downward and backward rotation of the mandible, increasing the vertical dimension of the lower face (Haas, 1970).
  • Subsequent recovery of mandibular posture noted in most cases (Wertz, 1970).

Rate of Expansion and Dental Arch Width Increase

  • Rapid Maxillary Expansion (Krebs, 1959, 1964):
    • Subjects aged 8–19 years showed an average dental arch increase of 6.0 mm (range: 0.5–10.3 mm).
    • Skeletal changes accounted for:
      • ~50% of the arch width increase in 8–12-year-olds.
      • ~33% of the increase in 13–19-year-olds.
  • Slow Maxillary Expansion (Hicks, 1978):
    • Subjects aged 10–15 years showed a dental arch width increase of 3.8–8.7 mm.
    • Skeletal response ranged from 16–30%, with lower skeletal response in older patients.
    • Buccal tipping of molars and skeletal segments contributed to arch width increase.
    • Asymmetrical angular changes between left and right molars and maxillary segments were observed.

Removable Plates and Sutural Growth (Skieller, 1964):

  • In subjects aged 6–14 years:
    • 20% of dental arch widening was attributed to sutural growth.
    • Sutural growth rate during expansion was significantly greater than during follow-up, indicating stimulated growth during expansion.

Removable Plates and Sutural Growth (Skieller, 1964):

  • Study on 20 subjects aged 6–14 years:
    • 20% of dental arch widening was attributed to sutural growth.
    • Growth rate at the mid-palatal suture was significantly higher during expansion compared to the follow-up period.
    • Suggests that sutural growth is stimulated during the expansion period.

Histologic Findings in Slow Expansion Procedures:

  • Sutural separation occurs at a controlled rate, maintaining tissue integrity during maxillary repositioning and remodeling (Storey, 1973; Ekstrom et al., 1977; Cotton, 1978).

Relapse Tendency During Post-Retention Period:

  • Relapse potential is reduced in slow expansion procedures due to:
    • Maintenance of sutural integrity.
    • Reduced stress loads within tissues (Storey, 1973; Cotton, 1978; Mossaz-Joelson & Mossaz, 1989).

Relapse Rates with Slow Maxillary Expansion (Hicks, 1978):

  • Relapse amount varies based on retention type:
    • Fixed retention: 10–23%.
    • Removable retention: 22–25%.
    • No retention: 45%.

Managing Relapse Potential:

  • Over-expansion during active treatment.
  • Prolonging the retention period to stabilize results.
Measurement/FactorQuad-Helix GroupRemovable Appliance GroupExplanation/Findings
Intercanine Width IncreaseSmaller increaseSmaller increaseQuad-helix arm did not touch canines until molar region expanded
Width Between First Permanent MolarsGreater increaseGreater increaseQuad-helix group showed more expansion in molar regions
Deciduous Molar Width IncreaseGreater increaseSmaller increaseQuad-helix expansion involved torque movements, removable appliance involved tipping
Mandibular Interarch DimensionsSmall changesSmall changesNo predictable pattern of change, maxillary expansion altered occlusion forces
Maxillary Arch Length (Expansion Period)IncreaseIncreaseBoth groups showed increase in arch length during expansion
Maxillary Arch Length (Retention/Post-Retention Period)Gradual decreaseGradual decreaseSmall net increase after retention and post-retention periods
Frontal Cephalometric Ratios (Active Treatment)Significant increaseSignificant increase, but less than quad-helixMaxillary intermolar width increased more in quad-helix group
Molar Tipping (Active Treatment)Minimal tippingHigh degree of buccal tippingRemovable appliance showed more molar tipping
Active Treatment Time101 days (average)115 days (average)Quad-helix had shorter active treatment time, but patients were observed less frequently
Retention Time3 months3 monthsSame retention time for both groups
Skeletal Expansion (Basal Expansion)Small basal expansionSmall basal expansionMinimal basal expansion observed in both groups
Orthopedic Movement of ExpansionMinimal sutural growthMinimal sutural growthSmall amount of basal expansion, similar to previous studies (Skieller, 1964; Hicks, 1978)