The ceramic prosthetics: dentures and crowns
Today, probably, everyone has heard of the metal-ceramic crowns, bridges structures. Why is gaining a lot of popularity these dentures — metal-ceramic gives you the opportunity to recover anatomical shape, color of teeth, chewing function and helps to normalize articulation, prevents the development of dentofacial deformities. What are the advantages and disadvantages of metal structures? What are the basic rules of hygiene care after prosthetic treatment? In what clinical situations is contraindicated, the use of these prostheses? Let’s deal!
What is the danger of damaged teeth
The destruction of the crown of the teeth, the violation of the integrity of the dentition leads to severe morphological and functional disorders.
- The lack of side groups of the teeth is the cause of sluggish mastication, displacement of the mandible.
- The destruction of the front teeth is breaking the biting food, articulation becomes a significant aesthetic problem.
- The dentition defects lead to the decrease in the height of the bite, the nomination of the opposing teeth, change in occlusion.
- Extensive carious cavity on the lateral surfaces lead to the shortening of the dental arches.
- The emergence of dental-jaw deformities affects the condition of the temporomandibular joint, muscular system and the whole organism.
Advantages of metal-ceramic prostheses
Nowadays, the use of ceramics has given us the opportunity to make as miniplates (tabs) and one-piece ceramic construction. But in a larger dental practice, the most common of all metal-ceramic restorations. This is due to their:
- good strength;
- high aesthetic parameters;
- chemical resistance;
- indifference to the periodontal tissues;
- the precise design of the chewing surface;
- dense coverage of the neck of the tooth;
- located edge of the construction at the appropriate level.
It is also important that metal-ceramic dental bridges great length for restoring chewing efficiency to 90-100%.
Disadvantages of metal ceramic dentures
In addition to the positive properties of cermet dentures have disadvantages.
- The installation requires removing a large number of tissues.
- Since the Foundation of the prosthesis is a metal frame, look these crowns are not as natural as, for example, ceramics.
- The increased strength of the structure can lead to abrasion, chipping the chewing surfaces of the teeth-antagonists.
- Possible allergic reaction to the metal.
- Sometimes the ceramic mass can split, exposing the metal framework. It looks not aesthetically pleasing.
It is important to note — not always correction chips using special composite materials yielding the desired result. Very often only re-prosthetics is able to completely eliminate the problem.
Let’s consider, in what clinical situations podiatrists recommend dental prosthetics using metal-ceramic.
- The presence of aesthetic defect in the coronal part of the tooth (the use of composite materials, micro-prosthetics proved ineffective):
- color change;
- multiple seals;
- loss of gloss.
- Malformations, defects of crown part of various origins:
- non-carious lesions (erosion, fluorosis, hypoplasia);
- hereditary pathology (imperfect amelogenin, violation of dentinogenesis);
- caries a large area.
- Defects of dentition.
Metal-ceramic dentures can be used when paraproteinaemia, in the case where the previously fabricated construction shown to be removed, as they do not meet medical, aesthetic, and functional requirements.
Prosthetics metal-ceramic in children and adolescents to apply, you should not. This is due to the topography, the size of the cavity of the tooth, and depth of dissection. Metal-ceramic bridge prosthesis to restore the integrity of the dentition to use is also not recommended, as it will constrain (lock) the growth of the jaw. In children use temporary metal crowns, making them shoot the minimum amount of tissue, which is good to prevent thermal burn of the pulp, and trauma iatrogenic pulpitis. The loss of teeth shown in children’s prosthetics (made by the orthodontist). The most widely used removable dentures, rings with loop (loop keeps the space required for the eruption of permanent teeth, and prevents shifting of adjacent teeth).
Relative contraindications to the use of metal-ceramic constructions are:
- pathologic occlusion;
- periodontal disease (periodontitis, parodontosis);
- pathological abrasion.
In each specific clinical case – individual approach. After therapeutic, orthodontic training, recovery of vertical dimension, and after complex therapy of periodontal disease, it is possible to create the necessary conditions for the application of the cermet.
Metal-ceramic prosthetics requires adherence to:
- For inter occlusal height (1.5 mm). It helps to model all the requirements of the chewing surface, the plot is cutting edge. And also gives the opportunity to accurately recreate the color of their teeth.
- The height of the stump of the prepared (peeled) of the tooth, which shall be not less than 4 mm. Excessive removal of tissue leads to a weakening of support, is the cause of frequent recementation and its destruction over time.
- Extent of covered defects. The use of frame-based alloys of noble metals allows to recover up to 2-3 missing teeth. While frames from base metals can be used in the defects, the size of which is up to 4 teeth.
Cermet stages of prosthetics
Beginning of orthopedic treatment is carried out after pre-therapeutic preparation, which includes removal of dental plaque, caries treatment and its complications. For correction of dentofacial anomalies orthodontic correction are shown. The quality of the preparatory activities directly depends on the efficiency of prosthetics.
Manufacture of metal structures takes place in several stages.
- Initial visit: clinical phase:
- The treatment plan.
- Teeth preparation, which will be installed metal-ceramic prosthesis.
- Taking impressions.
- The definition of color. Held in conjunction with the technician. The optimal time 11-13 hours. Important requirement – natural lighting, the patient is standing near the window in semi-profile to the light flux.
- The fabrication and fixation of temporary crowns.
- Laboratory phase includes:
- Otlipanie plaster models.
- Fabrication of wax reproduction of the prosthesis of the future.
- Replacement of wax on the metal.
- During the second visit, the podiatrist conducts:
- The fitting metal frame.
- Determines the nature of the closure with the teeth-antagonists.
- Studies the quality of the fit in the neck area, the boundaries of the location of the edge of the construction.
- If the bridge is made of sintered metal, the orthopedic surgeon also checks the flusher space (the gap between the denture and mucosa).
- Technician in the laboratory causes the ceramic mass, produces firing in a kiln.
- Third visit – final. The dentist tries on the finished design that determines whether they comply with the requirements. Records.
To date, the dentures on the basis of the cermet is carried out using alloys of precious and base metals.
Noble alloys have high corrosion resistance, good castability, and are biologically inert.
- noble palladium alloy «Superpal»;
- a gold and platinum alloy «Degudent» (gold -86%);
- domestic gold and platinum alloy «Super TK» (the content of gold -75%).
- Cobalt-chromium («Novarex», «Bondigui») are characterized by higher corrosion resistance, higher hardness and strength. These alloys are used for the frames of structures with defects of dentition long-haul (missing 3-4 teeth).
- Nickel-chromium (Viron, Supremium) alloys have better casting properties, easier handled, and in all other inferior cobalt-chrome.
Also, if a metal prosthesis will be made on the basis of Nickel, in patients may develop allergic reactions (about 10% of the population is allergic to Nickel). That is why Switzerland has completely abandoned the use of Nickel-chromium alloy.
Consider what complications can occur with ceramic prosthetics.
- The emergence of regional periodontitis.
- Recession of the gingival margin (decrease, atrophy of the gums).
- The development of pressure sores in the area under the intermediate part of bridge prosthesis.
- The mismatch of color ceramics the colour of natural teeth.
- Chipped ceramic mass.
- Raccomandiamo design.
Many people think that the crown is fine in itself protects the tooth, so cleaning doesn’t pay enough attention. It is fundamentally wrong. The quality of oral hygiene can increase the lifetime of the fixed prosthesis and, conversely, to reduce it.
The accumulation of plaque in the cervical region contributes to the development of inflammation of the gums. It begins with gingivitis, a complication which can become periodontitis. In addition to the inflammatory process occurs and bone tissue destruction, bare roots, there is abnormal mobility.
In addition to the occurrence of periodontal disease, a lack of proper cleaning leads to carious lesions of the root, disturbed the fit of the crown in the area of the tooth neck. And this is the reason that against the background of the visual well being of the tooth crown begins to slowly crumble.
To avoid complications, and to prolong the service life of prostheses, you must meticulously comply with all the rules of oral hygiene.
- Brush your teeth the experts recommend 2 times a day.
- After consumption of viscous products, the oral cavity should be rinsed.
- Except toothbrush (medium stiffness) and paste, use dental floss, brushes (for cleaning interdental spaces).
- The use of irrigators shows 1P/week. The irrigator is pre-filled with herbal decoctions or disinfectant solution.
In this article, we reviewed the indications and contraindications to the use of metal structures, their strengths and weaknesses, and stages of manufacturing.
Based on all the above, we conclude that the ceramic prosthetics is quite aesthetically pleasing, durable, and affordable method of treatment. Design how to restore the anatomy of the teeth and the function of the dentoalveolar apparatus. And with all the rules of hygiene care, regular visits to the dentist, the dentures in perfect condition and will last you more than ten years.