Дентал центр "Ліпінський"
Prostheses placement on implants
Prosthetic dentistry develops continually. Resulting from the increase of a number of various materials and technologies, there is a wide range of constructions, which prosthodontists place on the implants. Most of these constructions are being implemented almost instantaneously and enable the experienced professionals to do wonders. The patients visit a doctor with another problem and they can't keep up with the innovative medical techniques.

To make your smile beautiful again and to get back your dentition functionality, you need to consider placing the implant prostheses, which can replicate the shape, structure, and color of one or several missing teeth. Implant prosthetics solves the problems of damaged adjacent teeth, loosened prostheses і bone resorption. Individually made constructions look like the natural teeth and serve for decades.
A healing cap is a cylindrical construction made of titanium, which is being screwed in the implant. It allows creating the proper gum shape around the future construction. Healing cap looks like a low-pitch screw with a thick head.
The diameter of a healing cap head depends on the position of the tooth, which we need to make a prosthetic appliance for, and on individual structure features of the arch.

Healing caps are mainly made of titanium. This metal is both solid and light. Because titanium doesn't oxidize, it's perfectly preserved in the oral cavity environment.
Depending on the situation, the healing cap is placed along with the implant or after a while. Approximately 3-6 months after the implant placement. This time is needed for the implant to grow into the jawbone.
It's considered as an important construction element, which the esthetics of the final result depends on. It makes gums look as natural and attractive as possible after the prosthetic dentistry. It also provides comfortable teeth care and esthetics when smiling and talking.
It forms perfectly smooth edges of the socket if the doctor carries out the classic two-stage implant placement. This ensures that gum tissue will tightly and beautifully fit the abutment with a crown. A thread provides a firm attachment to the implant and the cylindrical shape makes it possible for gum to grow as necessary. Healing cap allows eating in peace and not worrying that food gets into the implant socket.
Stages of the healing cap placement:
  1. Local anesthesia is used.
  2. An incision is made in the gum where the implant will be placed.
  3. A cover screw on the top of the implant is screwed off.
  4. A healing cap is screwed in (the incision is stitched closed if needed)

One shouldn't confuse a healing cap with an abutment. In spite of certain common features, they are different constructions. They're meant to fulfill their specific functions. The only thing they have in common is that they both are being screwed into the implant.
An abutment is a connecting element between the implant and the crown. It's usually angle-shaped. It replicates the shape of the crown and it's needed for its firm fixation during the entire service life. The abutment is attached to the implant with a special screw and used to support the crown.
Abutments can be either standard or individual. Let's consider each one of them in more detail:

Standard abutments are the universal constructions, which come in several types and sizes for typical clinical cases (mass production reduces the price of construction and total cost of abutment). They come in various shapes, diameters, and sizes.
✓ universality;
✓ affordable price;
✓ there's a possibility to find a replacement.

- isn't always suitable for specific cases;
- the less pleasing esthetic outcome of soft tissue, which is one of the key factors of the crown;
- individual characteristics of a patient's anatomy aren't always considered.
Individual abutments are custom-made with the use of impressions and computer modeling to create the construction, which will properly attach to the crown and undertake most of the stress. These «adapters» allow achieving a perfect prosthesis positioning in any case. However, they are much more expensive than standard analogs.
✓ individual approach to each situation;
✓ good soft tissue esthetic outcome, which is one of the key factors of the crown;
✓ high-performance individual abutment as a result.

- Relatively high price (however, when the quality equals the price, a matter of money becomes secondary concern);
- It can't be replaced because it's fabricated individually.
There are following types of constructions:
  • angled – allows placing the prostheses at an angle;
  • ball – is used to place the removable constructions;
  • straight – the most convenient type for the prosthetics.
To make the individual abutment, it's necessary to: take the impressions, make the models, scan, create virtual 3D-models, fabricate the individual construction using the milling machine. Thanks to these procedures, the dentist eliminates even the slightest deviations during the construction placement.

It's worth noting that there is a separate classification by abutment materials.
Materials, which the individual abutments are made of, is an important characteristic. Individual abutments can be made of titanium, ceramics, and zirconia. Esthetics, quality, firmness, and durability of dental prostheses depend on the material. Individual abutment (ІА) prevents the food from getting between the gum and the implant, which can cause peri-implantitis – gradual resorption of bone tissue, gum recession, and implant exposure.
Titanium abutment is one of the most popular and frequently used ones. Its advantages are firmness, durability, affordable price. Titanium is recognized as hypoallergenic, it doesn't react chemically with anything during its time in the oral cavity. However, it's worthy of note that its use on anterior (front) teeth might worsen the appearance of the gum. These constructions might be visible through the gum or ceramic crown.
✓ good soft tissue esthetic outcome, which is one of the key factors of the crown;
✓ universality;
✓ affordable price;
✓ construction firmness;
✓ inertness

- allergic reaction to the alloys, which it's made of, sometimes occurs (very rarely);
- isn't suitable for esthetic restoration – dark metal might be seen through the crown.
A ceramic abutment is a good option for the patients, who are allergic to metal components of the construction. The ceramic abutment is made by casting considering the programmed characteristics, which allows achieving the pinpoint precision of inclination and thickness of the abutment. It's made for a smile to be beautiful and attractive.
✓ individual approach to each situation;
✓ good soft tissue esthetic outcome, which is one of the key factors of the crown;
✓ suitable for esthetic restoration of anterior teeth;
✓ doesn't react with mucosa;
✓ hypoallergenic.

- is more expensive than titanium;
- high price (however, when the quality equals the price, a matter of money becomes secondary concern);
- it can't be replaced because it's fabricated individually.
Zirconia abutments is an innovative solution, it's made of zirconium oxide, which combines the firmness of titanium and esthetics of ceramic. This material doesn't cause an allergic reaction. The abutment is durable and is placed not only on the anterior teeth but also on the posterior ones.
✓ combination of firmness and esthetics;
✓ individual approach to each situation;
✓ good soft tissue esthetic outcome, which is one of the key factors of the crown;
✓ suitable for esthetic restoration of anterior teeth;
✓ doesn't react with mucosa;
✓ hypoallergenic

- thick walls (if the walls are thin, the abutment will fracture under stress).
- it's difficult-to-process and it's more expensive than ceramic and titanium ones (however, it's as firm as the latter one);
- high price.
Prosthodontist, when choosing one or another type of crown fixing on the implant, proceeds from the following factors:
  • initial occlusion;
  • required retention level;
  • risk of potential complications;
  • current esthetic criteria;
  • accessibility to the surgical site;
  • prognosis of probable replacement of constructive elements.
The choice of crown fixing mechanism has to be made after the detailed analysis of the positive and negative aspects of each type of attachment of the crown to the abutment.

There are two types of retention in the current context:
✓ cement-retained restoration;
✓ screw-retained restoration.
Cement-retained restoration – attachment of the crown to the abutment with a cement. The abutment is screwed onto the implant with a screw, and the crown is placed onto the abutment in the same way as on the natural tooth.
✓ simplicity and esthetics, which are peculiar to the fixed constructions;
✓ unaffected by the implant placement angle;
✓ prolonged duration;
✓ thin layer when applying;
✓ provides firm material attachment to the tooth;
✓ restoration is faster and easier;
✓ cement-retained restoration is cheaper than the screw-retained one.

- cement might leak under the gum;
- can't be used in case of short clinical crowns;
- increases the risk of peri-implantitis in case of poor hygiene;
- can't be easily replaced.
Screw-retained restoration – the crown is attached directly to the implant with a screw via through-hole. After the placement, this screw is hidden with a polymeric material of the same color as the crown.
✓ decreases the risk of gingivitis due to the absence of cement;
✓ precise processing of attachment surface;
✓ no cement remains;
✓ construction is easy-to-operate;
✓ the crown is easier to replace or remove for a restoration;
✓ retains the anterior teeth in the upper arch more firmly.

- screw might loosen or break;
- screw-retained restorations make the esthetic outcome less pleasing, and initial implant placement at an angle leads to the fact that a hole is made on the edge of the crown or in the place where the filling material is attached poorly, which requires regular restorations.
- high price and need for professional hygiene.
Implant micro-prostheses are suitable for the restoration of one tooth, several teeth or the entire arch. All prostheses on implants can be made of metal-ceramic, ceramic, zirconia, plastic and metal-plastic (the latter two options are temporary).

Dental implant prosthetics is meant not only for a single-tooth restoration but also for solving the multiple problems of oral cavity – as a dental bridge or a removable denture.
1. Implant-supported single crowns – the implant is fixed in the place of missing tooth in one or two stages. In the first case, titanium implant with the abutment and the crown are placed on the same day, and in the second case, the crown is placed after the healing (3-5 months).
✓ durable;
✓ equal stress distribution;
✓ no need to mill or stress the adjacent teeth additionally, which decreases the risk of their fast wear and tear.

- the support in the form of a tooth root or implant is needed;
- the installation process is quite long if it is the two-stage implant placement.
2. A partial implant denture is a construction, which replaces a fragment of the arch (bridge). It helps to replace 3-5 missing teeth in a row (2-3 implants are usually placed with the crowns, which replicate the visible part of the tooth; there is a prosthesis between the implant and the crown).
✓ fast fabrication;
✓ easy care;
✓ restoration of any number of teeth;
✓ gives back the esthetics and restores the arch;
✓ makes the food chewing better;
✓ no need to mill the adjacent teeth;
✓ prevents bone resorption («bone subsidence») due to the equal stress distribution.

- long-term tolerance;
- fixation is unreliable in isolated instances.
3. A complete removable implant denture is a construction, which the patient can take out of the oral cavity to maintain oral hygiene and for the stress relief. False teeth are attached to the base, which is made of rigid acrylic resin, soft nylon, and its modifications. This base is attached to the gum and palate.
✓ restoration of the full arch in a short period.
✓ less number of implants is needed – sometimes two implants are enough for the entire arch.
✓ equal stress distribution.

- long-term tolerance.
- special care is needed.
- short-term speech problems.
- a short service life.
Are the implant prostheses safe?
Implants are made of inert materials, which survive in 90–98% of cases. All stages are projected in advance, so the doctor can change the approach and chose another material in case of a negative response of the organism.
What are the contraindications?
Absolute contraindications are the following: recent radiotherapy, blood coagulation problems, HIV. Relative contraindications are the following: diabetes mellitus, bisphosphonates use to treat the osteoporosis, diseases of the endocrine system, tuberculosis, mental illnesses.
How painful is the implant placement?
All procedures are carried out after the anesthesia, so the implantation is painless. 1% of patients feel minor pain and tingling.
When do the swelling and pain after the implant placement go away?
The swelling usually goes away in a week after the implant placement. Lower jaw implants completely fuse with the bone in 1–2 months, upper jaw implants – in 6 months.
When can I go to work / university after the surgery?
Better take 2–3 days off, to eliminate the risk of implant failure: you talk a lot at work / university, your jaw muscles actively move, so blood rushes to the place of implant attachment and the wound heels longer.
Computer modeling of prostheses helps to create a construction, which will perfectly fit the anatomic features of a particular patient.
CAD («Computer-Aided Design») is a creation of a computer model of teeth based on the obtained information about the shape of the jaw and natural teeth, height and thickness of the gum and the bone tissue volume. The professional enters data into a program and the copy of the patient's jaw is shaped based on this data.
He can create a model of any number of teeth, change their shape and size and estimate their esthetics and functionality.
CAM («Computer-Aided Manufacture») is a creation of crowns, bridges or other constructions based on digital data and CAD-models with NC machines. The computer automatically creates the physical copy of a three-dimensional model, bringing any professional's idea to life. The model then can be tested on a jaw dummy with the chewing simulation.
The creation of 3D-models of prostheses requires accurate primary information about the oral cavity. An intraoral scanner is a device of getting high-accuracy data about 3D geometry of teeth and jaw with the use of high-resolution cameras.

Intraoral scanner transfers the relief roughness, creates the model in color or in greyscale for a better look of various zones. Scanning takes up to 5 minutes, then an open-source file of the model is formed – it can be opened in any program for CAD-modeling.
Scanners, optimized for prosthodontists' needs, create three-dimensional models of teeth impressions, bridges and full-arch dentures, which allow placing the constructions onto the jaw in the program. Impressions scanning helps to avoid the blind zones, which aren't always considered in the model when scanning the patient's jaws.
Retesting the temporary denture by placing it on the patient's jaw and entering the 3D image into the program make it possible for the professional to improve the construction position and eliminate possible problems before placing the final denture. Testing the temporary construction in the patient's mouth allows getting valuable data about the comfort and esthetics of the denture.
Virtual modeling of future prostheses
The program automatically creates the preliminary options of missing teeth based on the opposing teeth or its pair in the arch: the creation of missing canine / incisor / molar based on the natural one on another side of the arch. The program creates these options on the three-dimensional model, which is digitized with a scanner.
Prosthodontist verifies the previous version of the model according to the height and thickness of teeth in the arch, lays the model of an opposing arch to get the information about the occlusion (contact between teeth of upper and lower arches), to change the points that hinder the proper occlusion.

Modeling of a full-arch denture is carried out based on the upper arch considering the occlusion special aspects; the professional can create the preliminary physical model of two arches to verify the position of teeth and bite and then do some tests.
3D printers in prosthetics
Printers create a three-dimensional physical model of a tooth, bridge or arch, using biocompatible polymers or plastic. This model is used as a temporary denture to estimate the esthetics and comfort when food chewing. The preliminary model helps to see the shortcomings of shape, color, position before it's too late. It also makes it possible to save money and time. The crown made of polymer or plastic gives back the esthetics during the fabrication of final crown made of zirconia dioxide, ceramic or aluminum oxide.

3D printers are used to create appearance physical models of the jaw (templates) and separate teeth in cases when the virtual models aren't enough for the professional to estimate the comfort of the future denture.
Milling machines
CNC-machines are used to create a highly precise individual crown based on digital modeling. This machine uses cubic or disk-shaped blanks made of pressed metal as a basis to create one crown, bridge or full-arch construction. The machine can be replaced with a printer: the fixed crown is made of solid materials that can be placed into the printer as a paste. And it's possible to get a high-quality denture by layering.

The milling machine carves the given construction after the information entering and the professional tops the prosthesis with ceramic abutment with metal-ceramic or zirconia coloring agent and bakes it in the oven to get the firm crown, which can be placed into the patient's oral cavity.

Implant prostheses make the smile beautiful again and make it comfortable to chew the food. Constructions are easily cleaned at home, easily restored by the dentist, don't damage the natural teeth and serve for over 15 years.