Bonded restorations (Inlay, Onlay, Overlay)
- Definition :
Partial coverage crowns or Inlay-Onlay and Overlay are prosthetic pieces made of alloy or ceramic.
They are formed of an intra coronal part: “Inlay” and an extra coronal part partially covering the dental crown: “Onlay”.
The Overlay is the extension of the onlay with total cusp coverage.
- Indications:
- Pulped teeth with favorable dental anatomy (wide, high, massive) and in good position on the arch.
- Reduced pulp volume
- Favorable occlusal relationship
- Good hygiene
- Indicated as anchoring means for small span bridges
- Healthy dento-periodontal complex.
- Advantage :
- Tissue economy (reduced dental mutilation)
- Cervical limits accessible and at a distance from the gingival fibromucosa.
- Disadvantages
- Preparations are more difficult to perform, as more skill is required than for the preparation of a full coverage crown.
- Less retentive than a complete peripheral preparation
- Reserve for clinical situations that allow it.
- Inlays Onlays on posterior teeth: (crowns 4/5):
The preparations are intended for single or multiple reconstitutions.
The design incorporates grooves, boxes, flutes and dentinal pits
- Maxillary cuspid teeth:
Reduction of the occlusal surface: (1.5mm on the support cusp and 1.0mm on the guide cusp and 0.5mm from the vestibulo-occlusal edge).
- Chamfer of the external slope of the support cusp.
Reduction of the palatal face:
- Reduction of a depth of 0.5mm
Reduction of the proximal faces:
- Contact point removal
- Avoidance of the vestibular face during reduction of the proximal face especially if it is the first PM.
Finishing of axial faces:
The finishing of the axial faces is done with a tungsten carbide fillet cutter.
The leave must be clear and continuous.
Production of the proximal grooves which must be parallel and stop 0.5 mm from the fillet.
- Preparation for partial crowns on cuspidate teeth of the mandibular arch:
- The crown is reserved for the single reconstruction of the 2nd PM and the mandibular molars. molars .
- It is used as a means of anchoring bridges
- On the 1st MP, crowns are rare because of the coronal perimeter and aesthetics.
- Reduction of the occlusal surface
- Chamfer of the external slope of the support cusp.
- Reduction of the lingual face
- Reduction of proximal faces
- Finishing of axial faces
- Creation of proximal grooves
- Vestibular chamfer
- Bonded restorations (Inlay, Onlay, Overlay)
The glued bridge:
Rochette was the first in 1963 to mention this type of bridge, which is a prosthetic piece bonded to the pillars and intended for limited anterior and posterior teeth.
It is also called the “Butterfly” or “MaryLand” bridge.
Indications and contraindications:
- Motivated patient with low caries risk.
- Limited toothing: 3-element bridge (ideal situation).
- Abutments without caries or significant reconstruction .
- Good periodontal condition.
- Orthocentric abutments: avoid tilted or misaligned teeth.
- Occlusion: the para functions give horizontal forces harmful to the bonding of the prosthetic part, Tight occlusion.
Glue and bonding:
- Email packaging:
Good adhesion of the restoration to the enamel guarantees optimum colour stability at the edges.
The conditioning will allow the creation of micro relief.
- Conditioning of dentin:
Adhesion to dentin is more difficult to achieve than adhesion to enamel because dentin has intrinsic moisture, a tubular microstructure, and a high organic content.
Bonded restorations (Inlay, Onlay, Overlay)
Wisdom teeth may need to be extracted if they are too small.
Sealing the grooves protects children’s molars from cavities.
Bad breath can be linked to dental or gum problems.
Bad breath can be linked to dental or gum problems.
Dental veneers improve the appearance of stained or damaged teeth.
Regular scaling prevents the build-up of plaque.
Sensitive teeth can be treated with specific toothpastes.
Early consultation helps detect dental problems in time.