How to Create an Apical Plug in Open Apex Cases: Step-by-Step Clinical Guide for Endodontists

1. Case Presentation and Initial Assessment

A pre-operative radiograph showed a failed revascularization attempt with non-set material (most likely MTA) inside the canal. After removing the coronal restoration, the canal was cleaned and working length was established.

💡 Note: The canal was prepared with a #60 file, indicating a very wide apex. This means a traditional master cone technique is not feasible.

2. Canal Disinfection and Interim Dressing

After thorough cleaning and drying, Calcium hydroxide paste (e.g., Meta paste) was injected as an interim dressing.

Why Calcium Hydroxide?

• Disinfection of the canal space
• Shifts the pH from acidic to alkaline, creating a favorable environment for healing
• Provides hemostasis and prepares the site for bioceramic material placement

📌 In open apex cases, it’s generally recommended to avoid single-visit apexification to allow proper disinfection and environmental conditioning.

3. Barrier Placement Considerations

In cases with periapical bone loss, placing a barrier (e.g., collagen sponge, membrane, or fleece) is highly recommended to allow controlled placement of the restorative material. These barriers typically resorb within two weeks.

However, if there’s no significant bone loss, the periodontium itself can act as a natural barrier.
In this case, due to the 25 mm working length, controlling a collagen barrier was not practical, so no barrier was placed.

read our guide about Sealer puff: Is it a sign of success or overfilling?

4. Choosing the Bioceramic Material

Putty formulations are preferred over powder-liquid types because of:

• Easier handling
• Faster setting times
• Better control during placement

Bioceramic material can be introduced using:

• An applicator or capsule injector
• Amalgam carrier
• Metal plugger

5. Initial Material Placement

Begin by delivering the material into the coronal and middle third using a bond brush or metal plugger.
Gently guide the material along the canal walls, allowing it to descend to the middle–apical junction.

6. The Challenge of Wide Apexes

Using a metal plugger in wide apexes is problematic because:

• It doesn’t adapt to the canal walls, causing material to be pushed apically or laterally
• Overcompaction can lead to extrusion beyond the apex
• MTA often sticks to metal pluggers, resulting in pull-back and voids

7. Creating a Custom “Paper Point Plugger”

To overcome these challenges, a custom-made plugger can be created using paper points:

Technique:

1. Start with three #80 paper points, align them together, and mark a reference point 1.5–2 mm short of working length.
2. Test the fit. Adjust by replacing one or more paper points with different sizes (e.g., #70, #60, #50) until the desired snug fit is achieved.
3. Once optimal fit is confirmed, bond the paper points together above the mark using flowable composite.

✅ This creates a plugger that:

• Adapts to all canal walls
• Prevents lateral displacement and extrusion
• Offers precise control during compaction

8. Why Paper Points Work Better

• MTA has a moist consistency; paper points absorb excess moisture, making the material firmer and easier to adapt.
• Unlike metal pluggers, paper points don’t stick to MTA, leaving a smoother and more uniform apical surface.

9. Incremental Layering Technique

Key principle: Do not exceed the intended 2 mm of apical plug material beyond the marked WL.
Work in small increments:

1. Place the first layer and compact using the custom plugger.
2. Allow initial setting before adding the second layer (check with a single paper point).
3. For subsequent layers, you can slightly adjust plugger size (e.g., add an extra #80 point) to avoid overcompaction.
4. Continue layering until a 3–4 mm apical plug is achieved.

Optional: After initial setting, a metal plugger may be used for final compaction if required.

10. Final Obturation

Once the apical plug has completely set (often requiring up to 24 hours), the remainder of the canal can be obturated using backfilling or lateral compaction techniques, depending on clinical preference.

🧠 Quick Clinical Quiz: Test Your Knowledge

Conclusion

Creating a well-adapted apical plug in open apex cases requires:

• Proper disinfection and canal preparation
• Controlled placement of bioceramic materials
• Smart use of custom-made tools like paper point pluggers
• Patience for material setting before backfilling

This technique offers predictable sealing, minimizes extrusion, and improves the prognosis of open apex cases.

References

1. Witherspoon DE, Small JC, Harris GZ. Mineral trioxide aggregate as an apical barrier in pulpless teeth with open apices: case reports. Pediatr Dent. 2008;30(3):197–202.
2. Al-Kahtani A, Shostad S, Schifferle R, Bhambhani S. Apical closure of nonvital permanent incisors using mineral trioxide aggregate. J Endod. 2005;31(2):117–119.
3. Sheehy EC, Roberts GJ. Use of calcium hydroxide for apical barrier formation and healing in non-vital immature permanent teeth: a review. Br Dent J. 1997;183:241–246.
4. Torabinejad M, Parirokh M. Mineral trioxide aggregate: a comprehensive literature review—Part II: leakage and biocompatibility investigations. J Endod. 2010;36(2):190–202.