Bridge intermediaries
| I | Introduction |
| It is the span of the bridge that crosses the toothless space and replaces the missing teeth, it is connected to the anchors by rigid connections or welds. Depending on the length of the bridge and the extent of the tooth loss, there are two types of bridges: short or long span. |
| II | Goals |
| Restore function and possibly aesthetics. Save or at least not cause degradation of the tissues with which it is in contact. The biological integration of the bridge intermediary is essentially linked on the one hand to its morphology, the nature of the material used and the constraints exerted on the missing teeth by means of the connections and anchoring means. |
| III | Morphology of bridge intermediaries |
| The shape of the trabeculae must be considered according to the morphological and physiological factors of the gingival ridges, according to hygiene factors, mechanical factors and finally aesthetic factors. Once assured during the production of the prosthesis, the prosthetic manufacture must be able to respect: The morphology of the surface in contact A good occlusal morphology A good axial morphology All of this being associated with the use of material which does not present any aggression at the tissue level, and on the other hand a good surface condition of its materials |
| IV | Requirements that the shape of the span must meet |
| There are 2 basic requirements: must allow self-stimulation of the tissues thanks to the maximum contact of the tongue, cheeks, lips and even food can exert at the level of its tissues. facilitate cleaning by the usual hygiene processes (mechanical processes). the durability of the bridge intermediary depends on the material used Do not attack the surrounding tissues. Aesthetics. The thickness of the span must have sufficient thickness depending on the alloy used and the length of the span (long span must be thicker). The resistance of the span is proportional. |
| V | External morphology |
| The bridge intermediary is related to the different tissues: Occlusal face responding to the antagonist teeth; Proximal faces responding to the anchoring means and the supporting teeth; Gingival face responding to the crest; |
- Vestibular and lingual surfaces corresponding to the cheeks and the tongue respectively.
| GO . | Relationship with antagonist teeth |
| The reestablishment of occlusal relationships with the antagonists will allow to restore masticatory efficiency and to maintain the stability of the occlusion. This morphology of the surfaces must be conditioned on the one hand by the functional movements of the mandible and on the other hand by the morphology of the antagonist teeth. The major objective is to direct and distribute the forces on the tissues of the deep periodontium of the abutment teeth. The cusp angulation must be carried out or analyzed, which is related to age, constitutional type (facial type) and the anterior addition. This angulation must correspond to that of the antagonist teeth, but it is the anterior guide which truly conditions the height, the orientation of the cusps on a semi-adaptable articulator. The width of the occlusal tables should be analyzed in a general way; it is recommended to reduce the vestibulolingual diameter of the occlusal tables to limit the importance of the forces applied during chewing, which will reduce their weakening. periodontal of the abutment teeth, however the reduction of the width of the tables will have the reduction of overhang, we will have a bite of cheeks or creation of area specific to the accumulation of plaque. |
| V. B. | Relationships with adjacent teeth |
| To avoid any deformation or fracture, it will be necessary to: Increase the thickness of the anchor opposite the span. Establish a wide span-anchor contact while clearing the embrasure to make it more accessible for cleaning. Ensure that the span is of sufficient section to avoid any deformation or fracture. |
| V. C. | From the point of view of axial morphology |
| The vestibular and lingual surfaces must have a convex profile, the proximal surfaces must delimit wide and easily accessible embrasures. The contact surface with the element adjacent to the anchors must not exceed the occlusal 1/3 and middle 1/3 zone to allow access for cleaning. |
| V. D. | Relations with the edentulous crest |
| The bridge intermediary must not create direct mechanical action, contact with the crest must be reduced and without pressure. It must not create direct or indirect mechanical aggression through plate retention, this retention must be minimized. |
by a polished surface and on the other hand the morphology must allow cleaning by maximum clear embrasures.
- Different types of bridge intermediaries
Depending on the nature of the relationship with the toothless crest, we distinguish 3 types:
- Supra mucosal
Classic shape
This arch, to limit bending, will have a so-called pentagonal section.
Afterwards, the connection is reinforced to increase resistance = more robust arch.
Stein indicates for a very resorbed mandibular crest an intermediate ovoid shape but whose tip always remains at a distance.
Sufficient space available
Reserved for the lateral mandibular sectors
The face opposite the ridge is convex to facilitate cleaning. They are the most hygienic but are not aesthetic.
- Mucous juxtaposition
Two main forms:
- Ovoid type
Egg or shell-shaped, convex intrados, low contact area with the ridge, clearance of embrasures, easy to clean, well tolerated.
Disadvantages:
- Vestibular face in its cervical part is not always aligned with the adjacent teeth, are not very aesthetic
- Used for mandibular teeth.
- Saddle type
Classic saddle/modified saddle only concerns the vestibular surface. The contact surface is small.
The gingival surface is convex and the embrasure is widely open on the lingual side.
Fairly easy hygiene, especially used when the ridge is not very resorbed = anterior and lateral sectors.
- Infra mucosal
To be avoided, large contact surface with the crest, difficulty of cleaning —
> causes inflammation.
| VII | Materials used |
| Precious metal, non-precious metal, resin, porcelainIt must be unalterable, must not oxidize under the influence of saliva and oral floraThe integration of your intermediary is linked to the nature of the material used in addition to the morphologyGlazed porcelain being a material of choice, studies have shown that both gold and resin, ceramic were well tolerated if they were also polishedOn the other hand, the resin intermediary gives off a foul odor in the long run due to the degradation of the surface by oral bacteria. (Problem remains)In all cases, it is necessary to avoid placing the junction of the 2 materials in contact with the mucosaThe intermediary must approach the shape of the natural teeth to promote aesthetics. |
Conclusion :
Among all these therapeutic choices, only a logical strategy based on a thorough, effective and rational pre-prosthetic study will allow us to offer the patient the type of pontic best suited to their situation for long-term restoration.
Bibliography
- SHILLINGBURG, Bobo, Whitsett, Jacobi, Brackett, fundamental bases in fixed prosthesis,
- SHILLINGBURG JACOBI BRACKETT fixed prosthesis preparations
- R. OGOLNIK M. VIGNON F .TAIEB fixed prosthesis principle and practice
Bridge intermediaries
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