Dental Literature Watch · Trial · Pediatric
Hall Technique Matches Conventional Crowns at One Year
TL;DR
- No caries removal, no local anaesthetic, no tooth preparation — the Hall technique seals the lesion under a preformed metal crown.
- At 12 months every restored tooth in both arms was a clinical success — no major and no minor failures in either group.
- 100% survival in both groups.
- The occlusal vertical dimension rose by 1.18 ± 0.68 mm immediately after Hall placement, and had returned to pre-treatment values within one month (p = 0.32).
- Conducted in primary care, not a university clinic — which is where the technique actually has to work.
The study
| Design | Non-inferiority, primary-care-based, two-arm parallel-group randomised controlled trial |
| Sample | 80 carious primary molars indicated for preformed metal crowns; 73 participants returned at 12 months |
| Groups | Conventional technique (caries removal and preparation) vs Hall technique (seal, no removal, no preparation) |
| Clinical outcome | All teeth successful in both groups; no major or minor failures |
| Survival | 100% in both groups at 12 months |
| Occlusion | OVD +1.18 ± 0.68 mm immediately; back to baseline within 1 month (p = 0.32) |
💎 Insight — what this means chairside
The occlusion data is the part that changes conversations
The commonest objection to the Hall technique is the open bite you can see the moment the crown seats.
This trial measured it — about 1.2 mm — and showed it self-corrects within a month. That is a number you can give a worried parent instead of a reassurance.
The commonest objection to the Hall technique is the open bite you can see the moment the crown seats.
This trial measured it — about 1.2 mm — and showed it self-corrects within a month. That is a number you can give a worried parent instead of a reassurance.
It removes the two things children hate
No injection and no handpiece, in a child who needs a crown on a carious primary molar.
For an anxious four-year-old the choice is often between a Hall crown and a general anaesthetic, not between two restorative techniques.
No injection and no handpiece, in a child who needs a crown on a carious primary molar.
For an anxious four-year-old the choice is often between a Hall crown and a general anaesthetic, not between two restorative techniques.
Primary-care setting is the point of the design
Techniques that work in a paediatric specialist clinic do not always survive contact with general practice.
This was run where the treatment actually happens.
Techniques that work in a paediatric specialist clinic do not always survive contact with general practice.
This was run where the treatment actually happens.
⚠️ The catch
Twelve months and 80 teeth, with zero events in either arm
A trial where nothing failed anywhere cannot discriminate between the arms — it can only show that neither did badly over a year.
Primary molars need to last until exfoliation, which can be five or six years.
A trial where nothing failed anywhere cannot discriminate between the arms — it can only show that neither did badly over a year.
Primary molars need to last until exfoliation, which can be five or six years.
Case selection is not tested here
The Hall technique is for a vital, asymptomatic tooth without signs of irreversible pulpitis or periradicular pathology.
This trial enrolled teeth already indicated for a crown; it does not tell you where the boundary of that indication lies.
The Hall technique is for a vital, asymptomatic tooth without signs of irreversible pulpitis or periradicular pathology.
This trial enrolled teeth already indicated for a crown; it does not tell you where the boundary of that indication lies.
Non-inferiority with no failures leaves the margin untested
When both arms score 100%, the pre-specified non-inferiority margin never comes into play.
Read this as reassuring rather than as a precise estimate of equivalence.
When both arms score 100%, the pre-specified non-inferiority margin never comes into play.
Read this as reassuring rather than as a precise estimate of equivalence.
⚡ Bottom line
- Carious primary molar, vital and asymptomatic, anxious child → Hall technique matched conventional at one year.
- Parent alarmed by the open bite → about 1.2 mm, resolves within a month. Measured, not asserted.
- Signs of irreversible pulpitis or periradicular pathology → not a Hall case.
- Expecting the tooth to serve five more years → this trial only followed twelve months.
🧪 Questions
Tap an answer — instant grade, deciding line, and the trap.
A 5-year-old with high anxiety has a cavitated occlusal-proximal lesion in a lower second primary molar. The tooth is vital, asymptomatic, with no sinus tract, no mobility, and no periradicular radiolucency. The mother is keen to avoid an injection. Which approach does the 2026 trial support, and what should you tell her about the bite?
Deciding line: both techniques achieved 100% survival with no failures at twelve months, and the measured occlusal vertical dimension increase of about 1.18 mm returned to pre-treatment values within one month. Trap: the permanent-open-bite option is the engineered trap because it reflects the widespread clinical fear this trial was designed to test; claiming lower Hall survival inverts the actual result, where neither arm had a single failure.