PROSTHETICS

Prosthetic crowns are a type of prosthetic restoration allowing for the reconstruction of severely damaged teeth –extensive carious cavities, numerous composite restorations. It is the most durable solution that lets our patients enjoy a beautiful smile for many years.

An aesthetic prosthetic crown is consists of two elements – the so-called base, i.e. a cap, and porcelain, which is fused onto that cap and which resembles dental tissue. The base can be made from metal (noble or common) or from special, hard porcelain.

CROWNS STEP BY STEP

STEP ONE

DIAGNOSTICS AND THE PREPARATION OF A TREATMENT PLAN

The first appointment is devoted to consultation and performing a panoramic X-ray, which constitutes the basis for drawing up a treatment plan together with a cost estimate. It is established which teeth require dental crowns. One very important stage of diagnostics is a detailed teeth analysis, paying special attention to any previous root canal treatment, and supporting it with the use of a crown-root inlay(see: crown-root inlays).

Root canal treatment is required in case of severely damaged teeth, teeth that have been reconstructed numerous times or teeth that require substantial stripping. This is often difficult to establish during the first appointment, and in the treatment plan this stage is described as “potential” (if the tooth is painful). Following root canal treatment, the teeth need to be fitted with a crown-root inlay, because as time goes by, such teeth tend to lose flexibility and might break.

STEP TWO

STRIPPING THE TOOTH, TAKING AN IMPRESSION, CREATING A TEMPORARY CROWN

During the second appointment, the tooth or an entire group of teeth is stripped to prepare it for the crown. While stripping, it is always necessary to leave an even layer of hard dental tissue that covers the pulp.This is achieved through shaping the stripped tooth stump to exactly imitate the original shape of the tooth, albeit in a smaller size. During tooth preparation it might turn out that it is necessary to carry out root canal treatment in order to avoid any potential complications, such asacute inflammation of the pulp, and eventually also of the periapical tissue.

A dental impression is then taken. At Villa Nova Dental Clinic we use top quality impression materials that are the only substances on the market characterized by unmatched precision of the reproduction of the tiniest detail in the impression.

Based on such detailed impressions, the prosthetic lab can create a perfectly fitting prosthetic (crown, bridge, veneer) characterized by the highest possible marginal tightness.

After preparing the tooth for fitting a crown and taking the impression, another very important stage of the process is fitting the tooth stump with a temporary crown. A temporary crown performs multiple important functions, but most importantly it protects the stripped tooth from irritating external factors, such as heat or cold etc.It also protects the patient and improves their appearance while they are waiting for the final crown.

STEP THREE

FITTING AND CEMENTING THE FINAL CROWN

The last appointment is devoted to fitting and cementing the final crown. In case of highly complicated and aesthetic reconstructions, fitting is performed during a separate appointment, but the crown is most often prepared properly and can be cemented onto the tooth without the need for any corrections.

ALL-CERAMIC CROWNS

High aesthetic expectations set for prosthetic restorations led to a number of studies focused on finding a prosthetic solution that will best imitate the natural tooth enamel. Currently all-ceramic restorations are considered one of the best. The high standard of restoration is achieved thanks to the use of computers at every stage of design and production. Thanks to this, the prosthetic restoration has the same characteristics as a natural tooth.

The main feature that distinguishes an all-ceramic crown from a classical porcelain crown on metal is the presence of a ceramic root that replaces the metal one and closely resembles the natural structure of the tooth.

1. HIGH AESTHETICS

All-ceramic restorations revolutionised the opportunities for obtaining crowns of high aesthetic value. A natural tooth is transparent enough for the light to penetrate through its entire thickness. A similar effect is achieved with all-ceramic restoration, which provides sophisticated aesthetic effects that imitate natural teeth.

In case of all-ceramic restorations and in contrast to porcelain crowns on metal, we can also avoid the blue gum effect around the neck of the tooth.

2. BIOCOMPATIBILITY

In the oral environment, metal alloys used in prosthetic restorations may undergo corrosion and can demonstrate toxicity. Corrosion is caused mainly by common metals ions.

The reaction to ions is manifested by allergy symptoms. Typically, local symptoms dominate, such as for example gum reddening. The reason for this are the ions penetrating the surrounding soft tissues. In case of all-ceramic restoration this phenomenon is absent, as Cercon is completely neutral to body tissues.

3. PRECISION, ACCURACY AND ARTISTRY

The ideal adhesion of the internal part of the crown to dental hard tissues is obtained thanks to using a computer at every stage of the creation of the crowns – CAD/CAM.

CAD, i.e. Computer Aided Design refers to the use of a computer at every stage of the design process, while CAM (Computer Aided Manufacturing) supports the manufacturing process. Thanks to the use of CAD/CAM, as well as the use of cercon oxide, we obtain prosthetic restorations of the highest quality.

The CAD/CAM technology, which is used in the manufacturing process enables to achieve perfect crown impermeability. Crown design is visible on the screen ,which allows for multiple zooming that takes care of the finest details of the crown. Computer-manufactured prosthetic reconstructions are characterised by high precision, and thus very good adhesion, which exceeds restorations produced using traditional methods. The entire process is completed with the use of a computer and design software, which eliminates many potential human errors.

The main advantages of all-ceramic crowns include:

• Stunning aesthetic effects;
• Natural transparency;
• Very high resistance and durability;
• Perfect adjustment;
• No tissue irritation or allergy.

They are used primarily to restore front teeth, as this material (zirconium dioxide) performs very well in areas of great aesthetic significance. Thanks to its physical properties zirconium dioxide enables to reconstruct not only single teeth, but also groups of teeth in the form of bridges (even very extensive), connectors or crown-root inlays used in the reconstruction of dead, endodontically treated teeth.

PORCELAIN CROWNS FUSED TO COMMON METAL

Such crowns are a last resort solution for aesthetic teeth reconstruction.

Why?

• they very often react with bodily fluids and surrounding tissues, causing allergy, with symptoms such as softening and reddening gums,
• after a few years, there is a risk that crown margins might appear, which results in the occurrence of unaesthetic grey discoloration on the gum edge,
• the metal cup blocks light, which makes such crowns look unnatural,
• the lack of possibility of achieving the high level of aesthetics afforded by all-ceramic crowns.

On account of the above reasons, we recommend all-ceramic crowns or crowns fused on gold to each patient who expects the highest standard of reconstruction. The main advantage of crowns fused on gold are their bacteriostatic properties, which prevent the development of secondary caries around the reconstructions.

Prosthetic bridges belong to permanent prosthetic restorations, used to fill a gap or gaps in the dental arch left by missing teeth. A typical prosthetic bridge consists of prosthetic crowns placed on abutment teeth (or implants) connected with the pontic or pontics (artificial teeth), replacing the missing teeth.

Based on the type of material used, they are divided into:

• ceramic bridges (made on a metal base –common steel or gold),
• all-ceramic bridges,
• composite or acrylic inlay bridges used as a temporary solution.

ADHESIVE BRIDGES

In case of single missing teeth, particularly those on the front,  in order to avoid the necessity of stripping often healthy dental tissues, we use a system of adhesive bridges known as Maryland. It provides excellent aesthetic results and patient comfort without the need for stripping adjacent teeth. The method itself consists in the reconstruction of the missing tooth with a new-generation composite material and fixing it to the lingual (internal) surfaces of the adjacent teeth by means of strong and extremely durable glass fibre.

CONVENTIONAL BRIDGES

This solution guarantees excellent aesthetic and functional results, as well as convenient use for the patient. The main inconvenience related to conventional bridges is the necessity of stripping at least two teeth adjacent to the gap. Depending on the patient’s preferences, the location of the missing tooth/teeth and the aesthetic requirements, all-ceramic or complex bridges are used. The former guarantee best cosmetic results, while the latter consist of a metal framework covered with aesthetic material (porcelain, composite) that imitates the shape and colour of the missing dentition. This type of restoration may be supported on both natural teeth and implants.

TYPES OF PROSTHETIC BRIDGES

Based on the type of material used, they are divided into:

• ceramic bridges (made on a metal base – common steel or gold),
• all-ceramic bridges,
• composite or acrylic inlay bridges used as a temporary solution.

The procedure of fitting a prosthetic bridge is very similar to fitting a crown (see -> crowns).

Dental tissues lost as a result of a large carious cavity, preparing a tooth for root canal treatment or mechanically breaking the crown of the tooth require restoration and strengthening with the use of a crown-root inlay before fitting a crown or a bridge.

Crown-root inlays are most often made of alloys of metals commonly used in dentistry and prosthetics. Common metal and gold alloys are most popular. One of the latest solutions are inlays made of composite or zirconia, which, owing to their tooth-like colour, make it possible to obtain translucency identical to natural teeth.

Crown-root inlays can be divided into standard and individual. Both have their indications and contraindications, as well as advantages and disadvantages. The dentist will choose which inlay is best for the patient.

Standard crown-root inlays are used:

• when a sufficient amount of tooth foundation is preserved,
• when there is a need for immediate reconstruction of the crown of a broken tooth,

A separate group of standard inlays are inlays made of glass fibre settled on appropriate composite material. Their advantage is their flexibility module, which is very similar that of the dentine. As a result, teeth strengthened with the use of glass fibre inlays are less prone to cracking and breaking. Another advantage is the colour of the tooth foundation reconstructed on the basis of a glass fibre inlay, as well as the fact that light can permeate this reconstruction similarly to the way it permeates a natural tooth. If we add to this an all-ceramic crown that contains no metal, we end up with a reconstruction that lets all the light through and behaves just like the adjacent natural teeth, regardless of the light conditions.

Unlike standard crown-root inlays, individual inlays are custom-made to fit the remainder of the tooth root. By using an individual inlay, we can achieve the best mechanical resistance of the construction, as well as an optimised shape. Such an inlay consists of the root part and the crown part.The root part is responsible for strengthening the structure of the root and appropriate transmission of the forces onto the root tissue, while the crown part is a prosthetic pillar, which is necessary for fitting a crown or a bridge.

In many cases, restoration of extensive tooth loss is unfortunately not possible with the use of bridges. In such cases, we can offer an alternative solution –a denture in the form of a removable restoration. However, it should be noted that when there are not enough abutment teeth, implantology becomes very helpful as the best solution for the problem of missing teeth.

At Villa Nova Dental Clinic we can offer you several types of dentures:

FULL DENTURES

These are removable restorations made of acrylic plastic. The main indication for their use involves toothlessness or extensive tooth loss, where the application of other dentures (skeletal, permanent, implant-based ones) is impossible. It is a popular solution available at a relatively low cost, but it also has many disadvantages: difficulties in adaptation, discomfort during use, inconvenience when eating, destructive impact on jaw bones and necessity of replacing them every few years.

SKELETAL DENTURES

Skeletal dentures are modern removable prosthetic restorations.Such a denture is supported not only on the gums and mucous membrane, but also on teeth; thus, it does not cause increased atrophy of the gums and bone tissue.The basic elements of the skeletal denture involve a metal base (skeleton), acrylic elements replacing the missing tissues (teeth and base) and brackets (responsible for holding the dentures to the base). Because of their low aesthetic value, brackets are increasingly often replaced with bolts, latches and telescopic crowns mounted on the teeth. In order to make it possible to hold down the denture in this way, it is necessary to fit crowns onto the adjacent teeth. The connection between the denture and crowns uses no visible metal elements (brackets, studs), which makes it possible to achieve the expected aesthetic result.

IMMEDIATE DENTURES

An immediate denture is a removable prosthetic restoration given to the patient just after tooth extraction, when the patient is still under anaesthesia. All the activities related to the preparation of such a denture are done beforetooth extraction. Such procedure allows the patient to avoid the discomfort related to the lack of teeth, as well as provides normal living conditions and the possibility of continuing professional work.It also promotes and improves healing of post-extraction wounds. However, the use of such a solution requires strict observation of the dentist’s recommendations, frequent check-up visits and maintaining perfect hygiene of the oral cavity and denture. Immediate dentures are a temporary solution used before the final denture is ready. Unfortunately they cannot be used in every case. Sometimes the teeth are in such a bad condition and so wobbly that there is a real threat of them falling out at the time of taking the impression. In such circumstances, only an early denture (the impression is taken immediately after extraction, while the denture is provided after around two days).

OVERDENTURES

Overdenture is a removable prosthetic restoration that covers the whole surface of the root or roots of remaining teeth, or implants. Such dentures are fixed on the roots or implants by a system of locks (usually ball catches). This type of restoration fulfils aesthetic needs, protects the jaw bone from atrophy and provides the patient with acceptable comfort. However, a prerequisite for the use of such dentures is that the patient acquires principles of perfect oral hygiene and regular check-up visits.

It should be noted that in toothless patients the overdenture may be supported on only two implants in the upper and lower jaw, which enormously improves comfort of use at a relatively low cost, compared to full dentures.

Reasons for tooth loss are complex:injuries, negligence of hygiene, diseases of the periodontium, to name but a few. The results of tooth loss have an impact on both aesthetics and the effectiveness of chewing food, which affects our well-being and functioning within society. Most of these problems can be solved by modern prosthetics. However, when there are not enough abutment teeth, implantology becomes very helpful. The introduction of implants into dentistry has revolutionised modern prosthetics, enabling completely novel therapeutic solutions. By using implants as the base, we can offer diverse prosthetic restorations:

• full overdentures,
• bridges replacing complete or partial loss of dentition
• crowns replacing single missing teeth.

Implants offer significant advantages, making them superior to other treatment methods. They improve the quality of life by making it possible to eat various types of food and not having to use denture adhesives. They also let patients achieve better appearance and better health by preventing bone atrophy, which makes it possible to preserve natural gum contours. Moreover, they improve chewing ability, hence improving digestion (see more -> implantology).

The dentist, working together with a prosthetic technician performs the reconstruction of the missing tooth or teeth based on an implant or implants integrated with the bone.An abutment is screwed into each implant, which makes it possible to fix a single tooth or a group of teeth.

Restoring a single missing tooth

The lack of a tooth in a visible area of the mouth may have a negative impact on self-confidence while speaking or smiling. The lack of a less visible tooth is not such a big aesthetic problem, but it may negatively impact the ability to chew, as well as other, adjacent teeth, leading to their displacement, which creates more locations susceptible to build-up of dental plaque and tartar.

A dental implant is a little titan screw, which fulfils the role of an artificial root and constitutes a stable base for the final crown. An implant allows to preserve the health of adjacent teeth, eliminating the necessity for stripping them for the purpose of creating support for a bridge. Dental implants look, function, and feel similarly to natural teeth.

Restoring several missing teeth

In the past, the loss of several teeth was dealt with through fitting bridges supported on teeth or partial removable dentures, which stay in place through the use of brackets.Implant-based bridges eliminate the necessity for using brackets or stripping healthy adjacent teeth in order to use them as support for the bridge. Dental implants serve as artificial roots, constituting stable support for the teeth in the bridge, which behave identically to natural teeth.

Complete loss of teeth

Traditional dentures do not help preserve the alveolar bone. As a result, as time goes by, the bone starts to disappear. The dentures no longer fit, which leads to erosions. Dental implants constitute a solid foundation for overdentures and bridges, guaranteeing their stable and comfortable position, as well as restoration of natural chewing ability. By stimulating the alveolar bone, implants support the preservation of facial structures, thus ensuring long-lasting aesthetic appearance. They also enable comfortable eating, speaking and smiling!

ADVANTAGES OF IMPLANT SOLUTIONS:

• They reduce the chances of damaging healthy, adjacent teeth, e.g. while stripping them before fitting a bridge.
• They can protect gum and bone tissues, contributing to the preservation of aesthetic face appearance.
• They are an alternative to removable and permanent dentures.
• They look, feel and function just like natural teeth – they are stable.
• They do not require the use of adhesives.
• They boost self-confidence.
• They help avoid awkward situations related to loosened dentures.

Chronic headaches, neck muscle pain, pain in the temporomandibular joints, ear, temple or teeth, migraines, cervical cavities, worn and sensitive teeth… all these could be symptoms of clenching the jaw and grinding the teeth during the night, known as bruxism.

Bruxism affects not just the teeth, but also the quality of life. Permanent pain, fatigue, stress–all these accompany people who experience the aforementioned problems and do not decide to begin treatment, which is simple, painless and affordable.

In case of bruxism and clenching the jaw at night with excessive force we use a so-called relaxation splint. As the name itself indicates, it has a relaxing effect on the muscles. The dental prosthetician takes an impression of the mandible, which becomes the basis for preparing an individual acrylic splint, which perfectly matches the patient’s teeth. The splint is worn during the night and it prevents the patient from clenching the teeth. This protects tooth enamel and weakens the strength of the masticatory muscles. The splint is recommended for patients who experience excessive tension in this area. It not only prevents excessive muscle contraction, but also protects the teeth from excessive pressure and from enamel erosion in patients who grind their teeth while sleeping.

Although using a splint is painless, some patients complain about small discomfort during the first few days of its use. It is only a matter of getting used to it. After a few days we cease to feel a “foreign object” in our mouth. The afflictions related to tension in the mandibular muscles subside after just a few days of using the splint, but in order to achieve long-lasting results, it must continue to be used for a few months.

Bruxism can be treated using other methods, too. At Villa Nova Dental Clinic we offer our patients an innovative method that involves the use of botulinum toxin (botox) (read more -> final touch – aesthetic medicine).

1. Is it necessary to replace any missing teeth?

Any missing teeth, even a single one, should be restored as soon after the time of loss as possible. The loss of even one tooth may lead to negative consequences within the whole masticatory system, such as migration of the adjacent teeth (inclination, rotation) and “elongation” of the corresponding opposite tooth that strives to make contact. Other complications include temporomandibular joint disorders that manifest themselves as morning muscular pain within the temple areas, as well as alimentary tract disorders. The other problem is aesthetic defects, such as an incomplete smile, shortening of the lower face, collapsing lips and increased wrinkles around the mouth.

2. What does the choice of the prosthetic restoration depend on?

The choice of prosthetic restoration being suitable for a given patient depends on many factors, such as:

• number of missing teeth;
• number and quality of remaining teeth;
• localisation of the tooth loss;
• condition of bone base, gums and mucous membrane;
• features of occlusion (bite);
• patient’s age;
• patient’s preferences;
• patient’s financial situation.

3. What options for the replacement of missing teeth are available in the case of complete toothlessness?

For many years the generally used solution in such a case has been a full denture. The advantages of such a solution include its availability, low price and satisfactory aesthetic effect. On the other hand, its disadvantage is low comfort in use. The denture simulates the masticatory function only to a small extent, and significant surface area of its plate covering the palate compromises the sensation of taste. Implant-based prosthetic restoration provides an alternative option that replaces missing teeth much more efficiently; such restoration includes:

• overdentures supported on 2-4 implants in the upper and lower jaw;
• bridges supported on at least 6 implants in the upper jaw and 5 implants in the lower one.

4. How are hygienic principles modified in the case of permanent dentures?

To prolong the durability of permanent denture to the maximum extent, special hygienic procedures have to be implemented which involve the use of additional hygienic tools apart from the toothbrush. The perigingival area of crowns and bridges requires special attention due to the tendency of build-up of bacterial plaque which is difficult to remove. Recommended equipment includes:

• super floss, rigid dental floss with a foamy thickened segment; the rigid portion is to be pulled under the cleaned denture element, and then the element is to be cleaned with the foamy portion;
• dental irrigator, a device producing a water stream that massages gums and cleans spaces which are difficult to reach.

5. How are hygienic principles modified in the case of removable dentures?

In the case of removable dentures, the denture itself should receive particular attention, apart from conventional care of the remaining teeth. A removable denture should be cleaned after each meal (at least twice a day). When the denture is removed from the patient’s mouth, it should be cleaned with a soft toothbrush and toothpaste, liquid soap or special cleaning agent. Special two-sided denture brushes are preferable, as the special shape of their bristle allows cleaning of even those places of the denture which are the most difficult to reach. Moreover, there are various cleaning agents, such as powder or tablets which dissolve in water, creating a liquid for denture cleaning. Such agents are particularly recommended to individuals with some physical disability.

6. What are the dietary requirements for patients under prosthetics treatment?

In general the diet of patients having permanent dentures is not changed, contrary to patients with removable ones. Patients who start using removable dentures, in particular full sets, should eat only liquid and semi-liquid food in the initial period and gradually introduce to more solid meals. Patients should eat smaller portions and avoid very hard and sticky food. In general, the meal time is significantly prolonged.

7. Is it possible to repair a prosthetic restoration by oneself?

Independent repair or correction of denture by the patient is not allowed; such an approach may destroy the restoration and lead to injury to the oral tissues. If the denture causes any discomfort, the patient should visit the dentist immediately.

8. Is the use of denture adhesive beneficial?

Agents which improve denture fixation are usually available in the form of powder that forms a sticky mass when mixed with the saliva. Such products may be periodically used in the initial period of getting used to the denture, and also by singers or actors during a show. In all other cases the use of denture adhesive is not advisable, as it may conceal possible imperfection of the denture, which should be detected and corrected in the surgery.