Crowns and dental bridges

Dental crowns

Even if a tooth has lost a great part of its structure through decay or other lesion, such as a fracture for example, it is possible for it to still remain alive. But this tooth will no longer function and look as it should be, so it could negatively influence a smile, otherwise beautiful.

A dental crown can fully restore this type of tooth. This natural replica of a natural tooth crown can fully restore the tooth function as well as esthetics.

Regaining shape and function with a dental crown

A dental crown is an artificial restoration, permanently cemented on the natural tooth. Most crowns are manufactured either from noble or non-noble metal covered with dental ceramics, or modern and perfectly biocompatible manufactured from full ceramics, meaning porcelain without metal or ceramics and zirconium, situation in which both mixing material are of white color. Regardless of their type, all are modeled to look and function exactly as the tooth they are covering. Crown modeling is accomplished either manually, in the dental technic laboratory, or with cad/cam systems, in laboratory as well as directly in the dentist office with CEREC system. Dental ceramics or stomatology porcelain have become the material of choice for dental crowns due to the unique properties they possess. Along with biocompatibility, resistance and strength offered by this material, porcelain provides an esthetic identical with the natural tooth.

Dental crown are used in several situations. For example, decayed teeth which have been repeatedly filled, must be covered with a dental crown to be reinforced and protected to fracture.

Teeth with root canal treatment, where root access has been achieved by digging an orifice inside the crown, must be protected through covering with an artificial dental crown. A crown can also improves the aspect of cracked, fractured, irreversibly color modified teeth or with growth anomalies.

While full ceramics crown are preferred in visible areas, for teeth restoration in large mastication force areas, such as molars, crowns with an additional resistance structure are preferred, such a metal-ceramics or biocompatible, zirconium-ceramics.

 

Manufacturing a dental crown

A dental crown manufacturing process begins with tooth preparation, more exactly by removing potential decays and reinforcing it with a filling. The dentist will polish teeth with special drills giving it precise shapes by a uniform reduction between enamel and dentin, so its covering with a crown can be possible, polishing being accomplished minimally invasive, as long as it is necessary.

Once the tooth is prepared, the dentist will record its impression and naturally, patient’s bite. Impression will include the teeth in question, neighboring teeth as well as antagonist teeth, meaning opposed, and will be classically recorded, with impression spoons and silicone materials settling within mouth, or modern with CEREC system scanner, on a digital impression form. For the first situation, the physical “package” will be sent to the dental technic laboratory and will include impression, bite and specifications regarding material type and color and the dental technician will realize the definitive crown in a period of days, even weeks. For the digital impression, the whole process lasts about an hour: based on optical impression the doctor projects even inside the dentist office, on a special computer, the crown and when all is completed, he places a porcelain cube without metal inside the drilling machine at teeth color, which in approximately 10 minutes, will be turned into a precise, functional and perfectly esthetic crown. That is why the method is also called “one visit dentistry”. If the dental crown manufacturing involves a waiting time, you will receive a temporary crown to protect the tooth and allow its use until the definitive crown is ready, especially when the tooth is placed in a visible area.

When the definitive crown is ready, dentist will remove the temporary crown and will place the definitive crown in its place. At this moment, there might be some slight adjustments needed for an improved comfort and aspect. After accomplishing these small adjustments, the dentist will polish, shine and cement it on the tooth.

Dental bridges

These have been successfully used for decades when replacement for missing teeth was needed. With their help we can replace with a fixed restoration a single or several missing teeth. It is composed of minimum 2 bridge poles, meaning 2 crowns fixed on natural teeth and in between the bridge body, meaning missing teeth replacement. Unfortunately, to fix the bridge on pole teeth, these have to be prepared by polishing with dental drills and sometimes, root canals are also treated. This means that, in a full dental implant era, when implant or implants insertion spares us from this tooth sacrifice, the dental bridge represents an invasive solution. The technological progress registered in recent years as well as researches in dental material domain, has led to the possibility of achieving extremely resistant and highly esthetic crowns and bridges. Although now the dental implant is considered “the golden standard” when talking about teeth replacing, the dental bridge still remains a viable alternative, especially for patients without a corresponding budget or to whom implant treatment is not considered as being feasible.

Constructively, there are 3 types of dental bridges:

  • With unaesthetic resistance structure – metallic (noble alloy from gold or platinum) and ceramic (porcelain) covering
  • With esthetic resistance structure – zirconium and ceramic (porcelain) covering,
  • Fully manufactured from ceramics (lithium-disilicate), that hard, resistant ceramic, perfectly imitating natural teeth color and translucency, able to successfully support forces generated during mastication.

Dental bridge vs. dental implant

The dental bridge has represented a viable treatment option for many years, yet, as we have reminded, it had certain disadvantages

Polishing, practically natural teeth’s sacrificing to turn intro bridge poles is the major disadvantage. Not a few times, to achieve a dental bridge, polishing will involve on all surfaces a minimum of 2, even 2.5 mm, leading in root canal treatments, meaning the need of treating the canal or canals of the respective tooth. Along with the procedure invasiveness, it considerably raises costs, so the final bridge price end up being equal or surpass dental implant treatment costs.

On the other hand, the cement used as an interface between crown and abutment can “wash” in time predisposing pole teeth to decay and even gingival inflammation.

At the same time, if the patient is not careful with oral hygiene, below the body of bridge, food waste can accumulate and cause, through discomposure, gingival inflammation respectively periodontal disease. Due to dental implant advantages, they have increased in popularity lately while the dental bridge cemented on natural teeth treatment option has concurrently decreased.

On the other hand, there are situations, even if not numerous, where a dental implant is not recommended, dental bridge being an excellent alternative. For example, maybe there no sufficient bone in the area where dental implant must be performed and patient cannot undergo bone addition, Or, due to blood vessel or maxillary sinuses position. There are also situations when the patient can present serious problems, decompensated of general health (uncontrolled diabetes, immune diseases, metabolic diseases) which can interfere with healing and osseointegration mechanisms endangering the dental implant’s future.

Another scenario is of patients with bleeding and coagulation problems, where even if the implant does not represent a contraindication, the procedure itself can be dangerous. The bridge represents a good alternative for female patients, who, in order to prevent bone demineralization occurring during menopause, are intravenously administered medication known as bisphosphonates.

Also, dental bridged may represent a good alternative to chronic smokers, who cannot or are not willing to give up on smoking.