Properties of dentino-pulpal protective funds
1. Introduction
In his daily practice, the dental surgeon very often resorts, in order to successfully carry out his therapy, to the installation of materials intended not to last over time, ensuring a transition towards the creation of the final restoration.
The restorative materials used for these purposes are called provisional, transitional or temporary. The diversity of materials offered requires the practitioner to analyze all the selection criteria before indicating the material to be used.
Each material has different biological and mechanical properties that must be taken into consideration when choosing.
Unfortunately, due to work habits, this therapeutic decision sometimes comes down to a systematization and simplification of materials and procedures, leading the practitioner to use the same and unique material in almost all clinical situations he may face.
2.Definitions:
Dentino-pulp protection materials represent all the materials used as cavity bottoms or protective bottoms in dentinal and pulp cappings. They are intermediate materials between the dentino-pulp tissue and the obturation which aims to create a biomechanical barrier.
Unfortunately they do not adhere well to enamel and dentin and they dissolve and erode in oral fluids.
These defects have the effect of making them temporary. They are also used:
As a sealing joint for fixing cast reconstructions or orthodontic bands
These different materials are used as bases or liners .
3.Roles Dentino-pulpal protection materials
Coronal restoration after loss of enamel-dentin substance requires the use of biomaterials designed to restore the functions of the dental organ. When considering restoration on a tooth that presents a pathology, it is the therapeutic action of the material that is sought. This dentino-pulpal protection therefore has a dual role
– an active biological role through which we can expect a bactericidal action, an analgesic action, a restoration of pulp physiology, or a dentinogenetic action,
– a protective role, rather passive in which the material plays a role of
Barrier intended to protect the dentinal organ.
3.Qualities required of hair styling products
- Biological qualities: Biocompatibility
- Alkaline pH closest to that of living tissues in contact
- non-toxic and non-allergenic
- No irritation to other dental and peridental tissues.
- Safety for oral mucosa
- High efficiency, even at low concentration.
- Anti-inflammatory qualities In addition to the previous ones, the styling product must:
-have a lasting anti-infectious action, however weak it may be
– prevent any putrefaction
It was based on these requirements that it was considered appropriate to add antiseptics, antibiotics and anti-inflammatories to hair styling products.
- Physicochemical qualities
- No tooth staining
- No unpleasant smell or taste
- Adhesion to the dentin surface
- Sufficient mechanical resistance to pressure of the sealing material
- Compatibility with filling materials.
- Technical qualities
- Good preservation of the preparation
- Facilitate introduction.
4. The objectives of the styling material
A. Ensure marginal sealing : Sealing is a fundamental property of coronal restorative materials. The interface between a dentinal wall and a restorative or obturation material is said to be sealed when the material/tooth seal prevents any infiltration of fluids and/or bacteria.
1. Immediate sealing : depends
– membership: A material that adheres strongly to the tooth has a good chance of being waterproof.
– dimensional variations: if the material shrinks during setting, the stresses resulting from this shrinkage can be transmitted to the interface, leading to a loss of sealing.
– of the actual implementation
2. Intermediate or delayed sealing : depends
– the coefficient of thermal expansion: in the oral cavity, there are significant temperature variations. If the material and the tooth have different coefficients of thermal expansion, a rupture at the interface is possible and therefore a loss of sealing.
– their solubility in water and in acids: The dissolution of these materials then leads to a marginal hiatus around the restoration.
– their resistance to wear: in the event of occlusal constraints, internal cracks may appear in the material causing a loss of sealing.
B. biocompatibility:
Biocompatibility is defined as the ability of a material to elicit an appropriate biological response in a given application. Thus, temporary coronal restoration materials must not cause adverse effects (irritation, inflammation) on the pulp tissue or on the tissues of the surrounding oral sphere (periodontium, oral mucosa).
C. Be easy to handle
One of the main qualities required for a temporary coronal restoration material is its implementation : its handling, insertion and removal must be easy and take little time. But also its setting time must be fairly short.
D. Have a minimum hold over time
The temporary coronal restoration material must have minimum mechanical properties to last at least a few days without losing the seal it provides and must also have mechanical qualities allowing it to resist wear and occlusal stresses over time.
E. The cost
The cost of the temporary coronal restoration material must obviously be lower than that of the final restoration material and in proportion to its lifespan.
5.Choice of styling material:
When choosing the temporary restorative material, several clinical criteria must be considered.
A. Pulp vitality
Depending on whether the tooth is vital or not, the choice of temporary coronal filling material is different. Thanks to the biological properties of eugenol (analgesic, sedative, antibacterial, and anti-inflammatory action), eugenates are the materials of choice for temporary coronal filling on vital teeth. Similarly, CVIs are also recommended and this thanks to their activity
biological (bacteriostatic) and good pulp tolerance.
B. the delay time
The temporization period can vary from a few days to a few months depending on the clinical indication. These materials must ensure satisfactory hermeticity throughout the temporization period.
C. the age and pathological history of the tooth
-A rapidly evolving carious lesion in a young patient has widely open dentinal tubules without any underlying mineralization reaction. We then want a protective base with antibacterial properties, allowing a return to normal pulp health, and whose constituents are not cytotoxic, knowing that this dentin is very permeable.
-When faced with a carious lesion in an adult that has developed slowly, the dentin is less permeable and we can then directly favor a material based on its mechanical properties.
D. The shape of the cavity. (Number of remaining walls, thickness of the temporary filling)
The shape and extent of the cavity play an important role in the sealing of the dental material/tissue seal. Indeed, it is difficult to achieve a temporary waterproof filling on dilapidated teeth. The same treatment is not adopted for a superficial cavity and a deep cavity. In a deep cavity, the aggression due to a non-biocompatible material causes irreversible pulpal alterations. It will therefore be necessary to choose the best tolerated cavity base.
E. the overlying permanent restoration
It is the last parameter included in the choice and it allows you to fine-tune the different data.
- Dental amalgams aim to protect the dentin, then the
pulp, the diffusion of corrosion products. We also want protection against thermal variations, as well as a protective material with good mechanical behavior
-For superficial cavities, the use of a varnish is traditionally recommended because it limits the diffusion of the constituents of the amalgam.
-For a cavity of moderate volume, it is already necessary to protect the tooth from thermal variations, eugenolate and CVI are the most effective,
– For a deep cavity; the pulp is already attacked by an extensive carious lesion as well as by the preparation of the cavity.
The placement of calcium hydroxide is necessary, it is placed after disinfection of the dentin, only in relation to the closest pulp areas
- composites :
-For a superficial cavity, at a good distance from the pulp, the technique of total treatment of the dentinal surface by adhesive systems creating a hybrid layer is the most suitable.
-For a cavity of average depth, if the obturation is not subject to occlusal constraints, a thin layer of calcium hydroxide can be placed.
Otherwise, a light-curing CVI is recommended.
-For a deep cavity, very close to the pulp . A juxta- pulp calcium hydroxide is placed, covered with a photopolymerizable CVI.
Properties of dentino-pulpal protective funds
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