Dental bridge; price, types of bridges, examples

A dental crown is used to cover a tooth in order to restore its shape and strength. It is fixed to the tooth by cementing it in place with a special material used in dental surgeries.

A dental bridge is a widely used prosthetic option for restoring an edentulous tooth. The qualities that recommend it as a therapeutic means are:

• durability over time,
• resistance to masticatory stress,
• affordable price
• harmonious integration into the dento-periodontal complex.

Its name derives from the analogy of a bridge over the space left by the loss of teeth.

Anchored to the remaining teeth or dental implants, the bridge becomes the link between two teeth with variable spacing.

A classic dental bridge consists of crowns that fit over the remaining, previously prepared teeth and a bridge body that covers the edentulous ridges.

The dental bridge body, the portion that replaces the remaining teeth, may be in close contact with the underlying gingiva or at a distance of up to 2 millimeters. The first case gives us a particular aesthetic while in the second case the hygiene is much easier.

Definitions

Fixed bridge: A denture that is permanently attached to the natural teeth and replaces missing teeth.

Attachment: The crown covering the tooth that supports and supports the denture.

Bridge body: The artificial tooth that replaces a natural tooth.

Retainer: Component attached to the attachment element for retaining the denture. These can be minor or major.

Unit: The bridge body and aggregating elements are referred to as units. The total number of units in the dental bridge is equal to the number of bridge bodies plus the number of aggregating elements.

Saddle: The area on the alveolar ridge that is edentulous and where at least one missing tooth is to be replaced by an artificial tooth.

Connector: Joins the bridge body with the retainer or 2 retainers together. These can be fixed or movable.

Alveolar ridge length: The distance of the alveolar ridge between the natural teeth on which the bridge will be placed.

Abutment tooth: The tooth or implant that holds and supports the dental bridge.

Adhesively bonded bridge: A denture where the bridge body is connected to the surface of the natural tooth that is either unprepared or minimally prepared.

The prosthesis has two components:

1. The cost of pre-prosthetic treatments: removal of the nerve where and if necessary, rebuilding the prosthetic bridge on which the dental bridge will be placed.

2. The price of the work itself, which is determined by multiplying the number of elements (teeth) that the dental bridge has by the price for a single element.

Below are the prices for a single element of various materials:

– 800 lei – Full CrCo/ceramic crown (metal cap covered entirely with ceramic)

– 1000 lei – Eco-Line Zirconium/Ceramic crown (zirconium cap covered with Ivoclar ceramic)

– 1200 lei – Zicronium Crown/Multilayer Ceramic (zirconium cap covered with several layers of Ivoclar ceramic)

– 1400 lei – Anatomic Zirconium Crown (anatomically milled zirconium with Ivoclar ceramic finish)

Payment for the services provided in our office can be made through CardAvantaj in 10 monthly instalments, without interest.

The updated list of services and prices can be found here: https://draristide.ro/prices

Advantages of dental bridges

• There is no risk of being rejected by the tissues to which they are applied.
• Reduced execution time: after the teeth have been polished, they will be impressed and until the technician completes the bridge, the patient will have a temporary prosthetic work cemented. The patient will then leave the dentist’s office with a temporary restoration designed to partially restore aesthetics, phonation and mastication.
• The dental bridge can replace a variable number of dental units, calculated according to the arrangement of the edentations, the hygiene status of the patient as well as the health of the abutment teeth.
• Aesthetics are excellent, with zirconia, the shades, saturation and brightness faithfully mimic the natural tooth.
• The lifespan can exceed 10 years, but this requires good dental hygiene and regular visits to the dentist every 6 months.

Preparation, impressions, checks and cementation can be carried out in a minimum of two sessions. In the case of an edentulous gap with limiting teeth without pathological processes, grinding and impression can be done in the first session. At the next appointment, the prosthetic piece will be checked, small adjustments will be made and it will be cemented, provisionally or permanently, as appropriate.

Necessary conditions for a dental bridge to be made

• The remaining teeth, which are to be grinded, must be free of any inflammatory apical process or coronal destruction. Otherwise, their preparation will be carried out after treatment of the lesions.
• The teeth must be well implanted in the bone to support the dental bridge. In case of mobility, teeth cannot be included in the prosthetic plan.
• The edentulous space must not exceed the supporting capacity of the limiting teeth. The dentist will analyze the size of the space and indicate the optimal treatment solution.

Stability of dental bridges

As we have learned, dental bridges are ways of securing edentulous spaces using limiting teeth.

They have a high degree of stability to the action of masticatory forces.

Applied to teeth prepared according to a certain pattern, they will not rotate. Cementation ensures that they are firmly attached to the underlying hard structure and the similarity to the teeth they replace makes them fit harmoniously into the dento-periodontic complex.

Complications in dental bridges. Causes and Explanations

• De-cementation of dental bridges or dental crowns is most common.

The causes that can cause a dental bridge to become edentulous at frequent intervals are:

• poor adaptation to the prosthetic field (lack of friction, tilting)
• mobility of the prosthetic abutments on which the work rests
• the small number of posts on which the prosthetic work rests in relation to the size of the bridge.
• existence of extensions (leverage)
• the weight of the work (in bridges on the upper jaw)
• bruxism
• poor quality of the cement used
• the abutments are too angular, pointed, not shaped like a truncated cone, not retentive.
• inadequate occlusal adaptation (existence of overcontact points, occlusal surfaces or incisal mucosae that are in occlusion)
• failure of the patient to comply with post-cementing instructions (the time required for the cement to reach the optimum setting point involves avoiding masticatory loads on the dental bridge, these times vary from 20 minutes to several hours, depending on the type of cement used)
• interventions made by the dentist, on the work, for touch-ups, immediately after cementing, can affect the quality of the cementing due to the vibrations generated by the dental drill on cement that is still raw.

• Chipping of porcelain. Reasons why ceramic may chip or chip:

• Bruxism is the most common cause,
• poor occlusal adaptation (the way the two jaws meet in the bite),
• poor quality of the ceramics from which the dental work is made,
• the presence of a very hard body in food such as: gritty grains of salt, pellets in game/venison, pebbles or grains of sand in salad

• Inflammation of the gums. Causes:

• Inadequate hygiene at the junction between the dental crown and the gums. (tooth collar)
• Inadequate adaptation of the prosthetic work to the prosthetic field, existence of retentive areas or violation of the biological space in case of untimely sanding.
• allergies to various dental materials

• Rupture of dental work. Reasons:

• the existence of over-occlusion points
• manufacturing defects: too thin structure or air bubbles in the metal (in the case of metal-ceramic work)
• accidents

Dental bridge on implants

A dental bridge is a prosthetic work that is attached to at least two teeth, provided that there is an edentulous space between the two teeth.

The teeth supporting the bridge may be natural teeth, i.e. the patient’s own, covered with crowns or dental implants.

The teeth between these supporting units are in loose contact with the underlying mucosa or even suspended so as not to injure the soft tissues. The loose contact or lack thereof is achieved depending on several aspects:

• We will have contact with the underlying mucosa when the edentulousness concerns an aesthetic area, such as frontal or lateral in the upper region.
• No contact is preferred when the edentulousness affects the lateral mandibular area.
• Contact will also be designed according to the shape of the edentulous ridge.
• The relationship between the bridge body (the teeth found between the abutment units) and the underlying edentulous mucosa should be such that good hygiene can be achieved.
• Intimate contact with the ridge is more comfortable for the patient but does not allow for optimal hygiene.

The dental bridge on dental implants is similar to the one designed on natural teeth, except that the abutment teeth are represented by screws in the bone.

For each abutment tooth an implant is required.

Further, the crown caps will be joined together to form a single piece.

For edentulousness in which only one tooth is missing, it is not necessary to make dental bridges.

These will be protected using unitary work. Dental bridges are used when several teeth are missing and there are units to border the edentulousness.

Also, most dentists prefer to bond dental implants together to ensure that the masticatory pressure is evenly distributed and that one of the implants will not take on more load than the bone can tolerate.

Sometimes, patient habits, whether voluntary or involuntary, such as grinding teeth, holding objects between teeth, can lead to overstrain with possible adverse consequences on the integrity of the implants. Vicious habits increase the risk of losing dental implants.

A dental bridge that secures the implants considerably reduces this risk.

If there is not enough bone to place dignified implants, the local situation can be improved by bone augmentation.

The dentist will analyze the areas where implants can be inserted and decide on an appropriate treatment plan.

In some cases, lack of bone or space may lead to a change in the initial treatment plan.

In this case, imaging, namely CT (computer tomography) scanning, is of real help, as it gives us clear details about the quality and quantity of bone in a particular region.

Dental bridge on remaining teeth (on own teeth)

A dental bridge consists, as described above, of two or more crowns that are fixed to the abutment teeth and one or more dental crowns that close the gap left by the loss of a tooth.

Fixed bridges are strong and reliable, and in most cases, they are physiognomic and easily accepted by the patient.

Dental bridges are an effective solution for replacing missing teeth, providing both functional and aesthetic correction.

In terms of function, the bridge allows the patient to chew and eat normally, as there is no longer a space in the oral cavity to limit this. It also plays an important role in their phonation, allowing the patient to speak clearly.

Aesthetically, a dental bridge can compensate for the loss of natural teeth, especially if the crowns of the dental bridge are the right shape and color. This can help improve confidence in patients who are embarrassed by the aspect of their teeth.

Dental bridges can also provide benefits to neighboring teeth. Under normal circumstances, a gap in the jaw or mandible causes a gradual change in the position and inclination of the teeth neighboring the edentulous space, which can influence occlusion.

In contrast, when the bridge is used to replace missing teeth, the teeth adjacent to the bridge are held firmly in position to reduce the risk of displacement and subsequent occlusion problems.

In addition, the bridge can also help reduce the risk of bone loss and therefore maintain facial structure.

Many patients also prefer dental bridges because of the way they integrate into the oral cavity and their easy maintenance.

It usually takes a short time for a patient to get used to the foreign body feeling that a dental bridge gives. Unlike dentures, bridges do not need to be removed regularly for cleaning and can be cleaned like natural teeth by brushing.

Disadvantages of dental bridges

There are, however, also a number of disadvantages of this method of dentures. For example, if you develop a deep cavity, infection or periodontal disease in any of the supporting teeth, then the entire bridge may be compromised.

Therefore, your doctor should decide whether or not a dental bridge is a solution for you, after checking the integrity of your abutment teeth.

An error made by the dentist is making the bridge too long. This will put a lot of force on the abutment teeth that cannot be supported. Therefore, a careful analysis of masticatory forces should be carried out before making the decision to make a bridge.

The biggest disadvantage of dental bridges is tooth preparation, especially if it involves young teeth with small or absent restorations. Abutment teeth require fairly aggressive grinding, with reduction of dental hard substance and root canal treatments. Therefore, this method is more indicated when neighboring teeth already show crown damage.

Advantages and disadvantages of replacing teeth by this method

Contraindications of dental bridges

– Periodontally diseased remaining teeth. If the abutment teeth are already weakened by periodontal disease, the stress of taking over the load of the bridge body will cause rapid loss.

– Remaining teeth with incomplete old treatments or with apical reactions. In this case, retreatment of the problem teeth is indicated. The fact that some of them did not have an acute phase or the patient does not remember having had one, is not a factor that justifies loading some teeth without performing their retreatment, endodontically or surgically – as appropriate.

– Use of wisdom molars as supporting structures. Wisdom molars have a number of major disadvantages when considering their prosthetic treatment: restricted access, shape, volume, atypical number of roots and canals, often deficient bone implantation.

– A dental bridge should never rest on two abutment teeth where one is natural and the other is a dental implant. These two types of supporting structures have different degrees of mobility (the natural tooth has a certain degree of physiological mobility while the dental implant has no mobility at all – it represents an ankylosis).

For this reason, the dental implant will mobilize and be lost if it is used as a support post in a dental bridge where the other post is a natural tooth. Consequently, this situation with two different abutment teeth is contraindicated because it will do more harm than good.

– Patients who have a history of allergies should be tested before having acrylic or metal-supported bridges made.

Regardless of the type of bridge you opt for, effective and consistent hygiene along with regular visits to your dentist will ensure the longevity of your prosthetic work.

A bridge is a fixed dental restoration used to replace one or more missing teeth by placing a permanent artificial tooth on adjacent teeth or neighboring implants.

Types of bridges

Conventional bridge

Conventional bridges are bridges that are supported by ¾ full-coverage crowns, on lays and inlays on abutment teeth. In these types of bridges, the abutment teeth require preparation and reduction of dental hard tissues to support the denture. Conventional bridges are named according to how the bridge bodies are attached to the retainer.

Fixed bridges

A fixed bridge refers to the bridge body that is attached to the retainer on both sides of the space with a single insertion. This type of design has a rigid connector at each end that connects the abutment tooth to the bridge body. Because the abutments are rigidly connected to each other, it is essential that during tooth preparation, the proximal surfaces of the abutment teeth are prepared so that they are parallel to each other.

Bridges with extension

An extension bridge is a type of bridge where the body of the bridge is attached to the abutment tooth on one side only. The abutment tooth may be mesial or distal to the bridge body.

There is also a variant of this type of bridge, where the bridge body and abutment tooth are joined by a metal bar. Usually, a missing front tooth is replaced and supported by a back tooth. This type of design is no longer used today.

Fixed movable bridges

The bridge body is firmly attached to an abutment tooth at one end of the bridge (major support) and attached by a movable joint at the other end (minor support).

A major advantage of this type of bridge is that the movable joint can bridge the angulation differences of the abutment teeth on the long axis, which allows an insertion axis regardless of the abutment tooth alignment. This allows for a more conservative approach as the abutments do not have to be prepared so that they are parallel to each other. Ideally, the rigid connector should attach the bridge body to the more distally located abutment tooth. The movable connector secures the bridge body to the mesial tooth, allowing limited movement of this abutment tooth in the vertical direction.

Adhesive bridges

An alternative to traditional bridges is adhesive bridges (also called Maryland bridges). An adhesive bridge uses two “wings” attached to the body of the bridge with which it attaches to the abutment teeth. The abutment teeth will require minimal or no preparation. It is usually used when the abutment teeth are intact and free from damage of any kind.

Combination design

These bridges incorporate different elements from conventionally designed bridges. A popular combination is the use of a fixed denture with an extension.

Hybrid design

Bridges that incorporate elements from both conventional and adhesive designs.

Advantages and disadvantages of conventional bridge design

Advantages and disadvantages of adhesive dental bridges

Case presentation:

Patient presented for prosthetic restoration of both arches complaining of masticatory, phonic and physiognomic dysfunction.

Numerous edentations, remaining teeth were emaciated, dystrophic, deep carious lesions.

Collapsed occlusion, reduced lower facial floor.

Click on the adjacent picture for more details about this case.

The treatment plan proposed and carried out consisted of vital extirpations of all remaining teeth, performing Chrome-Cobalt RCRs and rebuilding of prosthetic bridges.

The crowns chosen were porcelain teeth on Cobalt-Chromium framework.

Case selection and treatment plan

Case selection

Proper case selection is important when considering fixed bridge treatment. The patient’s expectations should be discussed and a complete patient history should be obtained. Replacing missing teeth with a fixed bridge is not always indicated and both patient and restorative factors should be considered before deciding whether a fixed bridge is appropriate.

The lifespan of the bridge can be affected by its length, the area where the bridge will be fixed and the size, shape, number and condition of the abutment teeth used. In addition, any active disease, including caries or periodontal disease, should be treated and followed by a period of maintenance to ensure the patient’s compliance with proper oral hygiene.

Vital teeth are preferably treated endodontically where the aggregating elements are to be applied. Through endodontic treatment, teeth lose a large amount of tooth structure, which weakens them and makes them less able to tolerate additional occlusal forces. For posterior crowns it has been concluded in various studies that they have a higher risk of failure.

In the case of adhesively fixed bridges, the abutment teeth should ideally be unrestored and have sufficient enamel to support the metal fixture. In addition, there should be sufficient space to accommodate the minimum connector width of 0.7 mm and height of 2 mm.

It is acceptable for the abutment tooth to be minimally restored with small composite restorations, provided it is healthy. It is recommended to replace old composite restorations prior to cementation to ensure optimal bond strength through the oxide layer.

Teeth with active disease, such as caries or periodontal disease, should not be used as abutment teeth until the condition is stabilized. Once stabilized, periodontally compromised teeth can be used as abutment teeth, depending on the crown-to-root ratio described below.

Ante’s law, which states that the roots of abutment teeth must have a combined periodontal surface area in three dimensions greater than that of the missing root structures of the teeth replaced with a bridge, is used in the design of bridges. This law remains controversial in terms of supporting clinical evidence.

The crown-to-root ratio represents the distance from the occlusal/incisal surface of the tooth to the alveolar ridge in relation to the root length within the bone. The minimum crown-to-root ratio is considered to be 1:1, although a crown-to-root ratio of 2:3 is most favorable. As the proportion of tooth supported by bone decreases, leverage increases.

Root configuration should be considered when choosing abutment teeth. Divergent roots of posterior teeth provide more support compared to convergent, fused or tapered roots. Roots that curve apically provide greater support compared to those with a fixed taper.

The number of abutment teeth required depends on both the position of the teeth to be replaced and the length of the edentulous ridge. Extension bridges using a single abutment tooth are designed to replace a single anterior tooth and can also be used for a posterior tooth.

The occlusion of the bridge with antagonist teeth should be evaluated. This can determine which type of design is most suitable and therefore how many abutment teeth are required. In the case of adhesive bridges, the bridge body should have light contact in intercuspation and no contact in laterality movements.

Biomechanical considerations

Torsional forces occur when the bridge body is off the linear axis of the teeth, the bridge body acts as a lever arm. This applies particularly to bridges that protect edentulous teeth in the frontal area.

The displacement varies directly with length and inversely proportional to the occlusal thickness of the bridge body. The larger the edentulousness, the greater the displacement of the bridge.

The displacement is 8 times greater when the edentulousness requires 2 bridge bodies and 27 times greater with 3 bridge bodies compared to a single body.

It is possible that increasing the length of the edentulousness results in increased torsional force on the abutment teeth.

The thinner the bridge body, the greater the deformation.

If the thickness of the bridge body is reduced by 50%, this results in an 8-fold increase in deformation.

Choosing bridge bodies with an increased occlusal-gingival size and using high deformation resistance alloys for denture construction will help reduce this deformation.

Indications for use

1. Replacement of a single tooth or a small edentulous space.

2. Good oral health status and patient’s motivation to maintain it.

3. Periodontal status of the remaining dentition at a stable and satisfactory level.

4. Good quality abutment teeth with minimal restorations and sufficient surface area and enamel for adhesion.

5. Consolidation of periodontally compromised teeth to improve occlusal stability, comfort and decrease mobility. (Periodontally compromised teeth are also a contraindication).

6. As a fixed prosthetic modality after orthodontic treatment or extraction.

7. Patient unsuitable for implants. This may be due to inadequate bone levels, increased cost price or the patient not wanting implants.

Contraindications

1. Too large an edentulous size.

2. Patients with parafunction, e.g., bruxism.

3. Tooth mobility increases the risk of disintegration.

4. Malpositioned teeth resulting in poor aesthetics.

5. Inadequate abutment tooth quality, e.g., may have reduced surface area, reduced enamel or may be fully restored.

6. Increased risk of caries due to increased difficulty in maintaining oral hygiene around the bridge.

7. Increased risk of loss of vitality.

8. Allergy to basic metal alloys, e.g., nickel.

9. Poor patient motivation. Active dental disease (caries, periodontal disease) and poor oral hygiene.

Type of bridge body in relation to edentulous ridge

1. Suspended (hygienic)

2. Point contacts

3. Saddle

4. Semi-shaft

5. Ovate

A bridge aims to restore aesthetics, provide occlusal stability and improve function.

The bridge that provides good hygiene, has no contact with the adjacent alveolar ridge, making it best suited for squaring an oral hygiene. Because of the poor aesthetics of this type of bridge, it is most often used for mandibular molar replacement.

The point-contact bridge is the second most favorable in terms of its ability to maintain good oral hygiene, with the bridge body in contact with the ridge at only one point.

The saddle and half-shaft bridge have superior aesthetics to those discussed above, with the labial/buccal surface capable of restoring the aesthetics of a natural tooth from incisal to gingival edge. To minimize soft tissue coverage, the lingual/palatal portion of the bridge body is reduced to improve accessibility to maintain good oral hygiene.

For the half-shaft bridge design, the bridge body contacts only the buccal aspect of the alveolar ridge.

The ovate bridge contacts the adjacent soft tissue and conceals edentulous ridge defects with the application of gentle pressure. It is usually used in temporary bridges following tooth extraction to improve emergence of the profile and help shape the gingiva around the future fixed denture.

Types of bridges according to durability

Bridges can be temporary or permanent. The temporary bridge is a transitional restoration that protects teeth that are weakened by preparation and stabilizes the dental tissues until the final restoration is obtained.

Furthermore, it can provide insight into the aesthetics of the future permanent restoration and its appearance, which can help the patient accept the final result. Temporary restorations are designed to be used for a few weeks or months, they can be fabricated directly (in the dental office), or indirectly (in the dental laboratory).

They are usually tried in a few times to check that they fit correctly and that their edges fit well on the surface of the teeth and gums, and may need to be readjusted or adjusted.

Temporary bridges can be made of either acrylic resins or metal. Resins are the most commonly used, and are made of either cellulose acetate, polycarbonate or polymethylmethacrylate.

Other chemically activated resins include poly-R methacrylates: these are methacrylates with ethyl or isobutyl substances added to increase the strength of the material.

Also commonly used resins include BisGMA-based dimethacrylate and urethane di-methacrylate. Dimethacrylate-based materials have been found to be better than monomethacrylates for temporary restorations in terms of flexural strength and toughness.

Types of bridges by material

1. Metal, noble metals such as gold or alloys such as nickel-chromium.

2. Non-metallic. Can be either resin veneers, fiber-reinforced composite, porcelain fused to metal or ceramics such as silica, alumina or zirconium.

Acrylic resins and porcelain fused to metal

Acrylic resins were the first veneering material used to help restore the aesthetics of crowns and bridges, the aim being to maintain a color similar to that of natural teeth by attaching it to the vestibular face of the metal crown/bridge, but, however, the use of resins for dentures has poor stability and low abrasion resistance. Porcelain fused to metal was later introduced, which is composed of 2 layers (one opaque to cover the metal structure and one translucent to give the illusion of enamel).

Still, several researchers consider porcelain fused with metal the gold standard, as they have reported 95% success over a period of more than 10 years, which is one reason why all new types of ceramics are usually compared in terms of success rate and durability with it.

However, porcelain fused to metal restorations may show a grey discoloration at the cervical margins of the teeth, with the metal structure visible.

Emax

Emax ceramics offer high aesthetic properties, so its use has been increasingly popular, however, there is insufficient evidence to determine the longevity of Emax in dental bridges; some research finding a fair survival rate in the short term but not favorable in the medium term.

Restorative failures have been most reported in the posterior tooth region. Emax is available as press ingots or in CAD-CAM system. The use of Emax in crowns or bridges is not recommended for patients suffering from bruxism.

Zirconia

Zirconia is used in the frontal and lateral area in both fixed bridges and implants. Zirconia is manufactured using CAD-CAM technology. It has a high mechanical strength and can withstand high occlusal forces compared to other ceramic materials. In addition, it can resist the propagation of cracks in the core material, but cracks can frequently occur in the veneering material, leading to fracture, either in tooth-supported or implant-supported bridges. Research has shown that 3×3 mm connectors in zirconium bridges increase fracture resistance by up to 20%.

Although the use of ceramics in fixed dentures has been a popular option due to the realistic, highly aesthetic appearance, a Cochrane review found insufficient evidence to support or refute the effectiveness of ceramic materials for the treatment of fixed dentures in comparison with metal-ceramic dentures.

Clinical stages of dental bridgework

1. Assessment: Clinical assessment of the patient’s conditions required for the fabrication of a dental bridge. Detailed history (including medical history), appropriate assessment of the patient’s oral environmental conditions (including occlusion, caries risk, periodontal risk, radiological examination, sensitivity testing), assessment of the patient’s goals and motivation, selection of abutment teeth and bridge design.

2. Primary impression: Primary impressions can be taken with alginate for study designs. A facebow impression should also be taken to allow occlusion study prior to denture delivery.

3. Wax up diagnosis: This allows the patient to visualize what the definitive prosthesis will look like. Wax up can also be used to build up a cytostatic matrix which can then be used to make a temporary restoration.

4. Replacing fillings: fillings on abutment teeth with poor prognosis or old composite resin fillings for adhesive bridges should be replaced.

5. Teeth preparation: This should be completed with reference to radiographs and study models obtained during treatment planning. For conventional bridges, dental preparation should aim to preserve tooth tissue, ensure a parallel path of insertion, achieve correct occlusion and ensure well-defined preparation margins. The conicity of each abutment tooth should be the same. This is known as parallelism between abutments and allows the bridge to fit over them. Adhesive bridges require minimal preparation.

6. Final impression: An accurate impression of the prepared teeth must be made, along with an impression of the antagonist arch. Functional models are used to provide accurate occlusal information to the laboratory and to construct the prosthesis.

7. Occlusal registration: an occlusal registration is required when extended dental bridges are desired to allow correct correlation with the opposing arch. This may not be necessary if only a small number of teeth are to be restored.

8. Temporary restoration: temporary restorations should be used if possible to protect and maintain the prepared teeth until the final restoration is placed.

9. Probing: Clinical acceptability should be confirmed prior to final cementation. Evaluate the prosthesis on functional models and identify the cause of any problems present. Sometimes a period of provisional cementation is used to assess clinical acceptability prior to definitive bridge placement.

10. Final placement: Once the denture is satisfactory and clinically acceptable, the dental bridge is cemented and permanently fixed.

11. Review: Evaluation of bridges and management of any postoperative problems

Restoration fabrication

As with single crowns, bridges can be fabricated using the loss wax technique if the restoration is to be all gold or porcelain fused to multi-unit metal. Another fabrication technique is the use of CAD/CAM software to machine the bridge.

As mentioned above, there are special considerations when preparing for a multi-unit restoration because the relationship between the two or more bridges must be maintained in the restoration. That is, there must be proper parallelism for the deck to seat properly.

Sometimes the bridge cannot be inserted, but the dentist is not sure if this is because the spatial relationship between the abutments is incorrect or if the abutments do not actually fit the bridge made.

The only way to determine this is to section the bridge and try each abutment tooth. If it fits individually, the spatial relationship was incorrect, and the aggregate element that was sectioned from the deck body must now be reattached to it according to the newly confirmed spatial relationship.

The proximal surfaces of the sectioned units are roughened and the relationship is maintained with a material that will be applied on both sides, such as PATTERN RESIN™ from GC America. With the two aggregate elements individually placed on the prepared abutment teeth, resin is applied to the sectioned site to restore a proper spatial relationship between the two parts. It can then be sent to the laboratory where the two pieces will be bonded and returned for a final retest or cementation.

Advantages of bridges

Dental bridges offer several advantages. They can usually be made in 2 sessions, can restore the tooth’s masticatory function back, do not require periodic removal for sanitation, have a long lifespan and are aesthetically pleasing.

Failure of dental bridges

The most common reasons for dental bridge failure

1. Poor oral hygiene: As with other fixed prosthetic work, including dental bridges, maintaining good oral hygiene to prevent dental plaque from forming around the bridges is key. This will ensure long-lasting performance. One study examined the health of the gingiva around fixed bridges 14 days to 6 months after their insertion and found that the surfaces were more retentive to plaque, causing gum inflammation regardless of the material the bridge was made of, with the exception of solitary crowns which did not show the same effect.

2. Mechanical failure: These failures can occur due to loss of bridge retention following improper cementation, preparation or construction.

Fracture of the metal layer or bridge body can also lead to mechanical failure. Fracture in gingival-side bridge connectors is a common problem with most ceramic bridges.

1. Biological failure: This can occur due to decay in the tooth (one of the most common causes of crown and bridge failures) or due to pulp damage. Problems with abutment teeth such as tooth fracture, secondary caries or periodontal disease can cause discomfort and put pressure on surrounding soft tissues also causing biological failure of the bridge.

2. Aesthetic failure: This can occur at the time of cementation and include; color mismatch, roughness of edges or improper tooth contours.

Aesthetic failure can also occur over a period of time, including tooth wear, gum recession or tooth displacement.

1. Problems with abutment teeth: these can be affected by secondary decay, loss of vitality or periodontal disease, all of which can lead to bridge failure.

Oral manifestations of bridge failures

Failure of a bridge leads to clinical complications and patients may experience:

1. Pain in the oral cavity

2. Tenderness, bleeding and inflammation of the gums

3. Bad breath and taste disorders

Management of dental bridge dysfunction

The management of bridge dysfunctions depends on their extent and type, and these can be prevented by developing a thorough treatment plan with the patient, as well as regularly stressing the importance of maintaining a very good level of oral hygiene after the bridge has been placed. The importance of cleaning under the bridge body, using appropriate means of interdental hygiene, should also be reinforced, as plaque control around fixed restorations is more difficult.

Management options include:

1. Keeping the bridge under observation/revision

2. Repair, replacement or removal of any flaws