The Cleft Runs Through the Teeth
When a cuts through the gum ridge, which teeth go missing or grow wrong, and can we predict it from how big the cleft is?
💡 The sits exactly at the , so it is the most affected tooth, and the wider the cleft, the more teeth go missing.
Prerequisite check
- The is ventilated only through the Eustachian tube, which is pulled open by the tensor veli palatini during swallowing.
- In a , the muscles are abnormal, so the tube fails to open and fluid collects ().
What you will learn
Goal: Explain why a through the disrupts the developing , why the maxillary is the most affected tooth, and how cleft extent predicts .
- The upper front teeth sit in the in order: central incisor, , canine; the line runs right where the lateral incisor should form.
- Missing teeth () occurred in about 50 percent of one population overall, and the rate rose with cleft extent.
- was 34.5 percent in of lip/, 51.6 percent in CLP, and 70.1 percent in CLP.
- The can also cause the opposite, a supernumerary (extra) tooth, found in about 33 percent, plus small malformed teeth.
Model: Where the cleft sits relative to the teeth, and real population numbers
The upper front teeth sit in the of the in this left-to-right order: central incisor, , canine. In a complete like Mateo's, the cleft line runs through the alveolus right at the spot between the central incisor and the canine. That spot is exactly where the lateral incisor should form, which is why that tooth is the one most often disrupted.
A study of a German CL/P population counted dental anomalies. (missing teeth) was 50 percent overall, and it tracked with extent: 34.5 percent in clefts of lip and only, 51.6 percent in CLP, and 70.1 percent in CLP. The single most-often-missing tooth was the maxillary , missing 23.2 percent of the time. The same population also showed the opposite problem: supernumerary (extra) teeth in 33.3 percent. A separate 300-patient study found tooth agenesis in 66 percent, supernumerary teeth in 19.6 percent, and microdontia (small teeth) in 18.3 percent.
The pattern is clear: a does not just leave a cosmetic gap. It leaves a gap in the bone, disrupts the teeth at the cleft line, and sets up a lifetime of orthodontic and dental care.
Explore (work the model before reading on)
- Which tooth normally forms right where Mateo's line runs?
- What single tooth is missing most often in the population, and at what rate?
- Compare the rates by extent. What is the relationship between how much is clefted and how many teeth go missing?
- Why is the specifically the most affected tooth? Use the tooth-order model to explain.
- Predict: Mateo has a complete left . Is his missing-lateral-incisor risk closer to the lip/ group or the group, and on which side would you look first?
Guided notes
Where the cleft sits
- The tooth-bearing bony ridge of the upper jaw is the ____, and the full set of teeth is the .
- The single most-often-missing tooth at the is the maxillary ____ incisor.
Extent predicts loss
- Missing teeth is called ____, found in about 50 percent of one population overall.
- The rate ____ (rose / fell) with extent: 34.5 percent lip/, 51.6 percent CLP, 70.1 percent CLP.
The opposite problem
- A can also cause an extra tooth, called a ____ tooth, found in about 33 percent, plus small malformed teeth.
Reading the Research
- Skim the title and abstract first to get the gist.
- Circle the one sentence that states the main claim.
- Box the evidence the authors give for that claim.
- Mark one sentence that confuses you, and move on.
Vocabulary (the same words your classes use)
Track your progress today
Check these off as you work through the lesson, then submit. This tells Mr. Mendoza how you're doing so he can help the class. It does not replace turning in your producible.
Use the code Mr. Mendoza gave you, not your name. Saved on this device.
- Read the Model and answered the Explore questions.
- Filled in the guided notes in my own words.
- Defined the new vocabulary with an example.
- Built the producible: Chart Mateo at age 6 as his adult teeth begin to come in. In three short sentences a parent could read, write: which single tooth you will watch most closely and on which side, whether you would also check for an extra or misshapen tooth at the cleft, and one reason it matters now (a tooth needs bone to grow into).
- Wrote my Claim, Evidence, and Reasoning exit ticket.
Exit ticket (Claim, Evidence, Reasoning)
- Claim: A through the is likely to disturb Mateo's because ____.
- Evidence: Cite the population data on the most-affected tooth and on by extent.
- Reasoning: Explain why a wider raises the risk of missing teeth.
| Criterion | Proficient | Developing | Beginning |
|---|---|---|---|
| Complete | Every required part of the artifact is present and filled in. | Most parts are present, but one is missing or left blank. | Several parts are missing. |
| Accurate | The science and data are correct and match the evidence. | Mostly correct, with a small factual slip. | Key science or data is wrong. |
| Scientific reasoning (CER) | States a claim, backs it with specific evidence, and explains the reasoning. | Has a claim and evidence, but the reasoning is thin or missing. | Gives an answer with no evidence or reasoning. |
| Professional communication | Clear, organized, and labeled the way a clinician or scientist would write it. | Readable but disorganized or missing labels. | Hard to follow. |
| Submitted | Turned in the right way (Schoology for routine work) and confirmed. | Turned in, but in the wrong place or unconfirmed. | Not turned in. |
- CompleteProficient: Nothing is left blank: the model fills every part of "Chart Mateo at age 6 as his adult teeth begin to come in. In three short sentences a parent could read, write: which single tooth you will watch most closely and on which side, whether you would also check for an extra or misshapen tooth at the cleft, and one reason it matters now (a tooth needs bone to grow into).".
- AccurateProficient: Every number and claim matches the case evidence.
- Scientific reasoning (CER)Proficient: It names a claim, cites the specific evidence, and explains the reasoning, not just the answer.
- Professional communicationProficient: It is organized and labeled like a real chart note.
- SubmittedProficient: It would be turned in on Schoology and confirmed.
Where this leads: careers
What's next: We found that the leaves a gap in the bone of the gum ridge and disturbs the teeth there. But a tooth needs bone to erupt into, and Mateo's bone has a gap. How do we fill that bony gap so a tooth has a home and the gum arch is continuous again? We chase that next time.