Peter Schouten

Article by Peter Schouten

The restoration of endodontically treated teeth often requires the use of core build-ups to provide a foundation for the final restoration. Historically, root posts served as a common method to enhance retention and stability for core build-ups. However, resin composite materials have gained popularity for core build-ups due to their excellent aesthetics, adhesive properties, and versatility. As the reinforcement of the remaining tooth structure (and replacing the missing tooth structure) remains fundamental, the decision to use a root post is a subject of ongoing debate.

This article aims to explore several key factors related to restoring endodontically treated teeth using resin composite with or without the introduction of a root post.

HISTORY

Core build-ups with a root post originally used metal as a post material for their strength. Stainless steel, titanium, and gold were popular choices. However, concerns about potential complications like root fractures prompted a shift in treatment philosophy.

The advent of adhesive dentistry brought about the rise of resin composite core build-ups, offering a less invasive and more conservative alternative. The possibility of bonding restorative materials to dental tissue reduced the need to remove sound dental tissue. This shift in perspective allows for a more conservative approach, prioritizing tooth preservation while still providing sufficient strength and retention for long-term success.

POST OR NO POST

Preserving as much tooth structure as possible is a general prerequisite in modern dentistry. Therefore, omitting the use of a post must be considered, especially in cases where root dentine must be sacrificed to create sufficient space and access to insert the post. The decision to use a post should consider the following factors:

1. The amount and quality of the remaining tooth structure*
2. The presence of a ferrule effect
3. The clinician's experience

*Several studies suggest that in cases where an adequate amount of tooth structure remains and when the remaining tooth structure is of good quality, root posts may not be necessary.

THE AMOUNT AND QUALITY OF THE REMAINING TOOTH STRUCTURE

Preserving as much dental tissue as possible is the first requirement. The presence of at least two intact axial walls is considered ideal for optimal clinical outcomes. Teeth with no- or only one residual wall appear to have reduced survival rates compared to teeth with more than one wall.

THE PRESENCE OF A FERRULE EFFECT

The ferrule effect refers to the presence of a circumferential band of tooth structure encircling the coronal portion of the tooth. This effect has been shown to contribute significantly to the resistance of the restored tooth to fracture. Minimal ferrule dimensions are not set in stone. Some general recommendations can be given to help evenly distribute forces, resist occlusal forces, and give enough retention. The ferrule should ideally extend at least 2 mm above the cementoenamel junction, have a circumferential width of approx. 1 mm and a thickness of 1 to 1.5 mm. Finally, the axial walls should have a slight taper towards the occlusal plane.

Would you like to continue reading as a PDF? Please leave your email address below.

Article by Peter Schouten.

I am frequently asked questions about the intraoral repair of porcelain chippings. To achieve success in repairs, it is essential to consider several important issues.

Perhaps the single most crucial issue to recognise is why the chipping occurred in the first place. For example, if loading stress is the leading cause, this should be considered during the repair.

Other issues to consider are removal of contamination, optimal roughening and chemical activation of the surface, and the prevention of contamination during the repair. Also, a rubber dam should be used to isolate the working field.

FUNDAMENTALS OF ADHESION

Adhesive procedures can be only successful by using the proper substances and methods. Different kinds of surfaces often need different treatments for success. However, the three basic fundamentals of adhesion must be respected to achieve the best results.

1) Mechanical retention through a roughened surface.

2) Chemical activation through chemically active substances.

3) High energetic bonding surface allowing for optimal interaction (wetting capacity) between the surface and the applied medium. Contamination will lower the bonding capacities and must be avoided or removed in any case.

TYPES OF FRACTURE

The most frequent fractures are porcelain only and those that include exposure of the substructure in PFZ or PFM prosthesis.

Many cases present with only limited chipping to the porcelain, for example, at the incisal edge. To achieve a durable repair in this instance, start by increasing the bonding/repair area using a fine diamond burr to create a large bevel. A fine grit burr is preferable over a medium or coarse version because a higher number of shallow grooves deliver a more optimal bonding surface than lesser deeper ones do. Additional roughening of the adherent surface by sandblasting with alumina (50 µm grain size, 2 bar pressure) is highly recommended to increase the surface area further.

When repairing porcelain chippings where the substructure is exposed, it is essential to be aware that multiple substrates are dealt with, indicating a need to adjust the repair protocol accordingly.

Clean the roughened fractured surface thoroughly. KATANA™ Cleaner is the product of choice. It is a safe and easy to use product with high cleaning power. It can be used both intra and extra orally on all kinds of dental substrates. After rinsing and thorough drying, the surface is ready for the next step, chemical activation.

CLEARFIL™ CERAMIC PRIMER PLUS contains both silane and MDP and effectively treats both silica-containing ceramics and metal oxides (zirconia) and metals. After application and thorough drying, the composite restoration can be carried out immediately without an extra bonding step. The composite of choice is a durable flowable, CLEARFIL MAJESTY™ ES Flow. It has high flexural strength, even higher than most paste-type composites. Besides that, it adapts to the surface better and easier. Quick and easy polishing and gloss retention are other highly valuated qualities of CLEARFIL MAJESTY™ ES Flow.

HINTS AND TIPS

• Isolate the working field by using rubber dam
• Bevel the chipping extensively using a fine diamond burr
• Roughen the adherent surface, preferably by sandblasting
• Clean the bonding area with KATANA™ Cleaner
• Apply CLEARFIL™ CERAMIC PRIMER PLUS to the entire bonding area (including exposed zirconia or metal) and dry thoroughly
• Cover exposed metal with a thin layer of CLEARFIL™ ST OPAQUER and light cure
• Repair with a strong flowable composite, such as CLEARFIL MAJESTY™ ES Flow

REPAIR OF PORCELAIN CHIPPINGS VIDEO

No shade taking needed. Just one shade to cover all posterior cases. Even the larger Class I's and II's!

Anterior cases from B1 to C4 done with only two shades, without the need for shade taking. Can you imagine? No additional opake materials (light blockers) needed too.