Endodontic sealers (Sealers)
Sealers play a critical role in endodontics. Their main task is to reliably seal the complex root canal system and fill the microscopic spaces remaining between the primary filling material (filler) and the dentin of the canal walls. Currently, clinical practice distinguishes two main delivery forms of such sealers:
- Powder + liquid system.
A classic representative of this group is the material AH 26. The kit traditionally includes a glass bottle containing powder and a tube with liquid (a special resin). The main feature of working with this form is the need for manual mixing. The dentist or assistant mixes the components on a glass slab or a special paper notepad until a homogeneous consistency of the desired thickness is obtained.
- Paste + paste system.
A more modern option, exemplified by Thermaseal Plus. The kit includes two tubes: base paste and catalyst paste. This delivery form significantly simplifies the clinician's work. It ensures the most convenient, fast, and, most importantly, homogeneous (uniform) dispensing and mixing of components without the risk of proportion errors, which frequently occur during manual mixing of powder and liquid.
Gutta-percha points (Gutta-percha points)
Gutta-percha traditionally serves as the primary filler material, which physically occupies the main lumen of the cleaned root canal. For ease of use and predictable results, the points are dispensed in plastic compartmentalized cassettes, forming assorted sets.
The key characteristics of gutta-percha points are their strict standardization and physical parameters:
- ISO standardization. All points are strictly standardized. The size indicated on the packaging corresponds to the diameter of the point tip itself in hundredths of a millimeter, according to the international ISO system.
- Taper (Taper). This is an indicator of how much the point widens from the tip to the base. The standard marking .02 on the packaging indicates a 2% taper. In practice, this means that for every millimeter of length from the tip, the diameter of the point increases by exactly 0.02 mm.
Color-coding (Color-coding)
To enable the clinician to instantly and visually identify the required point size during treatment, a universally accepted international color-coding system is used. The colors are strictly linked to ISO sizes.
The standard assortment cassette presents the following sequence of sizes and their corresponding colors:
- 15 — white
- 20 — yellow
- 25 — red
- 30 — blue
- 35 — green
- 40 — black
This system completely eliminates confusion when retrieving points from the cassette.
Briefly: answers to topical questions
What steps does the direct composite tooth restoration protocol include?
The main steps of aesthetic composite restoration include:
- removal of the oxygen-inhibited layer;
- removal of excess material;
- determination of occlusal relationships and correction of the restoration contour;
- anatomical contouring;
- finishing and polishing.
What is the purpose of phosphoric acid during the preparation stage for composite placement?
Phosphoric acid (at a 37% concentration) is used as a conditioner for enamel and dentin demineralization. Its application ensures the removal of the superficial enamel layer (about 10 µm) and the formation of pores to a depth of 5 to 50 µm. This is necessary for the subsequent creation of micromechanical adhesion of the composite to the hard dental tissues. As a result of acid etching, the surface is prepared for the application of primer and adhesive, which contributes to the formation of the hybrid layer and reliable fixation of the filling.
What functions does the adhesive system (bonding agent) perform when placing a composite filling?
The adhesive system performs a bonding function when placing a composite filling:
- provides the bond between the composite, the hybrid layer, and the enamel;
- contributes to the formation of the adhesive layer and the sealing of dentinal tubules.
The hybrid layer provides a strong bond with the dentin adhesive and composite, and serves as a protective barrier preventing the penetration of microorganisms and chemical substances into the dentinal tubules and pulp.
Depending on the system used, the smear layer is either transformed or dissolved and removed, followed by the demineralization of dentin.
What materials can be used as the primary root canal filler?
Gutta-percha points are used as the primary root canal filler. Gutta-percha is the main material for filling the root canal lumen. The points are standardized in size according to ISO and are color-coded by size.
Which instruments are used for the finishing and polishing of a composite restoration?
The following are used for the finishing and polishing of a composite restoration:
- finishing knives — straight and curved;
- diamond burs with an 8–30 µm grit size;
- 24–32-bladed tungsten carbide burs and carbide finishers;
- rubber, silicone, and felt points/cups;
- polishing discs;
- strips for finishing proximal surfaces;
- polishing pastes and special brushes.
To memorize the ISO color-coding (15–40), use the mnemonic: "White Yellow Red Colors Blue Zebra Black" (White - 15, Yellow - 20, Red - 25, Blue - 30, Green - 35, Black - 40).
Class and exam questions
What is the difference between a sealer and a filler?
A filler (e.g., gutta-percha) is the main bulk material filling the canal lumen. A sealer is a root canal sealer that fills the microspaces between the filler and the canal walls.
What does the .02 taper mean on a gutta-percha package?
This means that the diameter of the point increases by 0.02 mm for every millimeter of its length, starting from the tip. This is the standard 2% taper.
What is the advantage of the paste-and-paste sealer system over powder and liquid?
The paste-paste system (such as Thermaseal Plus) provides faster, more convenient, and homogeneous mixing without the risk of proportion errors, unlike manual powder mixing on a glass slab.
What else to study on this topic
- Composition and properties of AH 26 material
- Polymerization specifics of Thermaseal Plus material
- Chemical composition of gutta-percha points
- Root canal obturation techniques using sealers
Master the entire topic in the «Propaedeutics of Dentistry» course
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Other topics in "Chapter 7. Endodontics"
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