CLASSIFICATION OF ANCHORS IN FIXED PROSTHESIS

CLASSIFICATION OF ANCHORS IN FIXED PROSTHESIS

1- TOTAL COVERING CROWNS :

– these are hollow devices which cover the entire prepared abutment tooth; we distinguish:

• Metal crowns.
• Mixed crowns: – CIV (vestibular inlay crown).

– CCM (ceramic-metal crown).

• Ceramic or resin crowns (Jacket crown)

1-1- cast metal crowns:

• It is a metal cap that is entirely cast.
  •  Indication:
    • for PM and M
    • as a unitary means or means of anchoring a bridge.
    • as a hook or attachment support for PPAs.
•  Contraindication :
  • anterior teeth.
  • reduced dental volume.
  • big bad tooth position.

  1-2- ceramic or resin crowns (JACKET):

• It is a crown that is made entirely of cosmetic materials (resin or ceramic).
• INDICATION:

• previous restorations.
• slight dental malposition.
• dysplasia and for dwarf teeth.
  • CONTRAINDICATION :
• significant overbite.
• dysfunction and para function for the same reason.
• importance of pulp volume.
• end-to-end occlusion.
  • BENEFITS :

-Incompatible aesthetic result.

• biological result.
• does not require a casting process.
  • DISADVANTAGES:
• delicate preparation, requires perfect adaptation in the cervical part to have a good limit.
• limited clinical indications.
• fragility relative to the material with which they are made.

1-3- Mixed crowns:

 1-3-1- The vestibular inlay crown (CIV):

• cast metal cap with a housing on its vestibular face intended to receive a resin or ceramic facet.
• Indication:

• visible aesthetic teeth.
• Single anchoring or bridge means.
• Benefits :
• It combines solidity and aesthetics.
• Disadvantages:

• significant mutilation of the vestibular surface.
• Unsightly problem with the use of resin.

1-3-2- the ceramic-metal crown: (CCM)

• composed of a layer of ceramic material fired under vacuum and fixed on a metal cap which bonds to the tooth.
• Indication:

• For all teeth.
• As a unitary reconstruction or as a means of anchoring a bridge.
• Benefits :
• It combines the strength and precision of a cast element with the aesthetic quality of ceramic.

– It has a longer lifespan than the jacket crown.

2- PARTIAL COVERAGE CROWNS:

• The ¾ crown: the preparation for this crown involves ¾ of the tooth concerned and only the vestibular ¼ which remains intact.
• the inverted ¾ crown: SAME as the ¾ crown but here the buccal ¼ (palatine or lingual) remains intact.
• the proximal half crown: this is a variant of the ¾ crown. The distal face and not the vestibular and lingual faces remain intact.
• 7/8 crown: this is a crown that is indicated for the reconstruction of teeth whose mesio-vestibular cusp is intact.

* Two-sided inlay onlay * Three-sided inlay onlay

CLASSIFICATION OF ANCHORS IN FIXED PROSTHESIS

• INDICATIONS:

• pulped teeth to maintain aesthetics.
• means of single anchoring or a low-load bridge.
  • CONTRAINDICATIONS:
• teeth prone to decay.
• short, hypersensitive teeth.
• voluminous pulp.
  • BENEFITS :
• Limited dental mutilation and preservation of aesthetics.
• easy access to edges and for finishing.
• easy hygiene and protection of the marginal gingiva.
  • DISADVANTAGES:

– Decreased retention compared to other crowns and difficulty of execution.

• The facets:

– Veneer preparations are placed under the double sign of simplicity and tissue economy without forgetting the aesthetic value.

• Type I: preparation without lingual return:
• It is a preparation which concerns the vestibular face of the tooth without reaching the free edge.

• Indication: young teeth, slightly damaged teeth, slight anomaly in color or texture, teeth in normal position, multiple restorations.
• Contraindication: mandibular incisors (the free edge must be covered: mechanical and aesthetic reasons).

• Modified Type I: recessed preparation without lingual return:
• It is always a preparation which concerns the vestibular face of the tooth but with a greater thickness than type I, and without reaching the free edge; called “recessed window”.
• Indication:

– are intended for very stocky teeth and cuspidate teeth: very massive canines with thick enamel, PM and 1st maxillary molars.

• Type II: preparation with return on the free edge:
• intended for teeth requiring lengthening, the preparation is extended on the free edge and is accompanied by a return on the lingual face (the proximal faces remain intact).
• Indication:

• Tooth to be lengthened.
• Tooth requiring great aesthetic characterization in the free edge area.
• Seeking high mechanical resistance.
• Maxillary central incisors in cases of CL II dev 2.
• Mandibular incisor slightly dilapidated.
• Maxillary and mandibular PM with engulfment of the vestibular cusp.
• Transformation of the canine into a lateral incisor (case of agenesis).

CLASSIFICATION OF ANCHORS IN FIXED PROSTHESIS

• Type III: half-jacket preparation:
• most recent development, it is the final stage of the facet before the jacket (the preparation concerns the vestibular face with a return to the free edge and the preparation of half of the buccal face including the proximal faces).

Indication:

• Tooth badly damaged or badly fractured.
• Old teeth.
• Mandibular incisors (thin teeth: type I and II preparations cause over-contouring).

3- Corono-radicular restorations:

.

The RCRs strode The RCRs cast the tenon tooth

3-1- cast coronal root restorations:

• The reconstruction by inlay-core or cast false stump is intended for devitalized teeth on which the placement of a fixed prosthesis is essential and it is a technique whose implementation is

long, often complex and always more expensive than for full-length reconstructions

• The inlay-core or inlay-onlay with root tenon is a cast metal pre-prosthetic reconstruction composed of:
• Indications:

• Restoration of teeth with extensive decay, having a juxta or slightly subgingival limit and/or whose residual walls are insufficient to consider a full restoration.
• Restoration of a tooth whose canal anatomy is incompatible with a prefabricated post.
• Restoration of a tooth with reduced volume.
• Tooth located in an occlusal context that does not allow the durability of a post-plastic material association to be ensured.
• Fixed pillar parallelism in case of large sealed proyhetic reconstructions.
• Contraindication :

• Its implementation significantly aggravates the deterioration of the tooth compared to its initial state and goes against the principle of tissue economy.
• The available crown height is insufficient to ensure the retention of a two-story construction.

3-2- The tenon tooth:

• RICHMOND sunk:

– this is the oldest technique in which the tenon is secured to the crown.

• Disadvantages:

• Difficulty of the impression in the case of an anatomical post to record perfectly and in a single step the canal anatomy and the cervical limit of the coronal preparation, this difficulty being increased in the case of multiple restorations.
• Frequent problem of loosening due to the direct transmission of mechanical stresses to the tenon.
• Indications:

• The available coronal height does not allow the interposition of a two-stage retentive restoration (anatomically very short or abraded teeth, very tight occlusion).
• Possibly for teeth with reduced diameter (mainly mandibular incisors).
• Contraindication:

• Deep coronal destruction making the dental tissue cerclage insufficient.
• Short or curved root not allowing a tenon of significant length compared to the clinical crown.
• Bridge whose abutment teeth are not parallel.
• Multirooted teeth with divergent roots.
• the DAVIS crown: it is a full crown made of porcelain or resin adapted to the root of the tooth to which it is fixed by a metal tenon called a “DAVIS tenon”.
• the single tenon crown: this is a crown resting on the root to which it is secured by a tenon made extemporaneously in the lab from an impression of the preparation of a tenon in place.
• the adjusted RICHMOND crown: it includes a cervical root cap which completely or partially crimps the root stump, a welded metal support and an aesthetic device.

• Indication:
  • used as temporary crowns.
•  Advantage :
  • speed of execution.
• Disadvantages:
  • difficulty of adjustment.
  • difficulty in choosing the DAVIS crown .
  • change of shade (resin veneer).

difficulty in recording the canal area

• .

CLASSIFICATION OF ANCHORS IN FIXED PROSTHESIS

Deep cavities may require root canal treatment.
Interdental brushes effectively clean between teeth.
Misaligned teeth can cause chewing problems.
Untreated dental infections can spread to other parts of the body.
Whitening trays are used for gradual results.
Cracked teeth can be repaired with composite resins.
Proper hydration helps maintain a healthy mouth.
 

CLASSIFICATION OF ANCHORS IN FIXED PROSTHESIS