It is believed that bone tissue is the strongest and most stable structure. human body. To some extent this is true, bones are really strong. It must be taken into account that bone tissue is a living structure in which many processes occur. It is capable of growing, regenerating and destroying.
Dystrophic processes in bone tissue jaws are enough common occurrence. Destruction or atrophy is a decrease in the bone tissue of the tooth. It becomes smaller in height and width, and its density may change. With untimely prosthetics, orthodontists often encounter atrophy of the alveolar process.
The structure of the bone tissue of the tooth includes osteoblasts and osteoclasts. Osteoblasts promote the production of collagen and calcium salts. These cell connections are responsible for bone repair and growth. Osteoclasts, on the contrary, promote atrophy. They contain lysosomes, which, when exposed to specific proteolytic enzymes, destroy collagen compounds. IN in good condition Osteoblasts and osteoclasts neutralize each other, but during changes in the body, the action of osteoclasts predominates.
The main reason for the pathological decline is the disruption and slowdown of metabolic processes and blood flow in the bones, a decrease in the amount blood vessels. As a result, the bone tissue of the teeth does not receive proper nutrition and is depleted. A similar phenomenon is caused external factors and diseases of a chronic or acute nature.
The main causes of atrophy of hard gum tissue:
Tooth extraction is the most common reason atrophy. The gums at the removal site cease to take part in chewing, the load subsides, metabolic processes are slowing down.
Changes in gum tissue occur almost immediately, but the patient cannot independently diagnose the pathology. About three months after tooth loss, the bone begins to noticeably shrink and narrow. Outwardly, it resembles a bent saddle. After a year, the process progresses, making implantation impossible without the use of additional measures.
Atrophy caused by extensive infection, trauma, or systemic diseases, can be intensely manifested in a certain place or differentiated throughout the jaw. In this case external signs less noticeable, but at the same time the structure of the bone tissue of the tooth changes. They become brittle and loose, and soften. The jaw bones are unable to support tooth roots. As a result, a person can lose teeth even at an early age.
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The consequences of bone tissue destruction are very serious. They directly affect physical health the body, and also bring problems of an aesthetic nature.
Possible consequences:
Thanks to advances in orthodontics and science, restoration of jaw bone tissue has become possible. The process of artificial restoration is based on knowledge of the structure and functioning of bones. The idea is to “replant” or implant one’s own tissues or synthetic materials of a similar composition (specially treated animal tissues or specific compounds of calcium and phosphorus).
The regeneration process is not fast. At in various ways The procedure takes on average 6 to 8 months.
Effective regeneration is only possible with urgent installation of dental implants. Considering the degree of destruction, it is carried out before bone augmentation or in parallel with it.
In cases where degenerative processes were caused internal pathologies, simultaneously with dental therapy, the cause itself must be cured. Otherwise, the destruction may resume after some time.
Indications for restoration procedures:
You need to understand that the main indication for bone regeneration is the impossibility of installing implants. A jaw bone that is too thin or short complicates the procedure. In addition, this affects the quality and durability of the work.
Depending on the degree destructive processes apply following methods therapies that help build bone tissue:
The most effective method Treatment is considered to be surgery. Modern technologies and materials are kept to a minimum side effects, speed up the rehabilitation process and give a good chance of complete regeneration.
Operations on the top and lower jaw carried out differently. This is due to anatomical features their structures.
Prosthetics upper jaw if there is insufficient bone area, there is a risk of damage to the maxillary sinus. As a result, it develops chronic sinusitis or sinusitis. For the upper jaw, dentists use sinus lifting (bone tissue augmentation). The operation can be open or closed. The first method is more complex, is carried out in several stages, and is indicated for bone heights less than 7 mm. Closed sinus lift is more gentle and is applicable when there is 8-10 mm of bone.
How is bone grafting performed? The operation takes place under local anesthesia. With the help of a small incision, the gum is peeled off, the periosteum remains intact and alive. The bone is cut along the ridge line using ultrasound. This is the most safe method with a minimum of damage. A regenerating material or drug is injected into the bone cavity. At the end, stitches are applied. The rehabilitation process is quick and fairly painless. The formation of new cells occurs within 8 months.
Jawbone deficiency is a fairly common problem in dentistry, in particular when dentures on implants are required. To solve this problem, specialists resort to non-standard options or perform a procedure for increasing the volume of bone tissue.
When is bone grafting necessary for implantation?
When implantation occurs, preliminary osteoplasty is required in almost half of the cases. Most dental patients with the issue of implantation turn to specialists a year or more after the loss of a tooth (teeth). Whereas this period should not exceed 2-3 months. Every day the jaw bone becomes thinner without loads and decreases in volume. It becomes impossible to carry out implantation on atrophied gums. And then the specialist prescribes bone grafting.
If there is a deficiency of bone in the upper jaw during implantation, there is a risk of rupture of the maxillary sinuses. In this case, the length of the implant may be greater compared to the thickness of the jaw bone. An artificial root can pierce the sinuses and this will lead to infection, causing sinusitis. In the lower jaw, if there is insufficient bone volume during implantation, there is a risk of damage mandibular nerve. In addition, if you neglect the minimum permissible dimensions of bone tissue between implants, as well as between artificial roots and your teeth, and, in particular, the thickness of the bone walls, both in front of the implants and in the back, then the bone around the artificial tooth will begin to atrophy. As a result of this process, the implants will become loose or the gums will recede, exposing the metal part of the artificial tooth.
Who should not undergo bone grafting and when?
Contraindications for osteoplasty, as for any surgical intervention, many. Surgical bone grafting cannot be performed:
Obviously, with such a huge list of contraindications, the preoperative stage is very important. Preparation for osteoplasty consists of a thorough examination by a specialist, a blood test (extensive and for sugar) and radiography of the nasal sinuses. In order to facilitate rehabilitation period and neutralization of such side effects For inflammation and swelling, the specialist prescribes oral antibiotics and hormonal drugs. The bone healing process can last from 3 to 8 months.
Pros and cons of bone grafting
Often patients refuse implantation due to the need for additional operation on the jawbone, fearing that it is very complex and fraught with unpleasant consequences. Is osteoplasty really as scary as it is made out to be? Most dentists believe that the risk of complications with bone grafting is no greater than with any other surgical procedure if all precautions and sequence are followed correctly. At the same time, osteoplasty provides the patient with a number of advantages:
However, the patient after osteoplasty will have to endure the inconvenience and restrictions associated with long-term rehabilitation, which usually takes at least a month, depending on the various factors. During the recovery period, you should protect yourself from viral infections, including ARVI. They can delay rehabilitation and contribute to infection of the operated tissue. Artificial bone should not be exposed strong pressure. At excessive loads The transplant material may become dislodged, and the result of all work will be jeopardized. The patient runs the risk of disturbing the location of the implant even with a sharp sneeze and a strong hysterical cough. To improve health, special immunomodulatory drugs may be prescribed. Experts recommend temporarily giving up air travel, diving, active sports, and drinking drinks through a straw.
Osteoplasty: types
Several bone grafting technologies are practiced in dentistry:
NTR. The NTR technique is considered the simplest, atraumatic and frequently used. In addition, in most cases, this technology allows for simultaneous implantation. Using NTR, both the height and width of bone tissue are increased. The technology involves the use of implanted bone material and a special membrane. The augmentation is performed using synthetic granular hydroxyapatite, natural bone material of animal origin (bovine), as well as autogenous bone chips taken from the patient. In the latter case, bone tissue is taken from areas where there is enough of it, for example, from the branch of the lower jaw in the figure eight area. Nai best results gives grafting using autogenous bone material. The bone takes root well in almost all cases. The only thing is that this technology requires a small additional operation to harvest the bone. Bone material from cattle is very effective, but with this method it is theoretically possible to catch the virus. In terms of infection, artificial materials are absolutely safe, but they are less effective. A protective membrane must be placed over the implanted material and the gum mucosa is tightly sutured over it. The membrane isolates the bone material from the soft tissue and prevents it from being washed out through the sutures. Resorbable or absorbable membranes and non-resorbable membranes are used, which are surgically removed from under the mucosa.
Bone block. Osteoplasty technology using a bone block is more complex, more traumatic and does not allow for simultaneous implantation. Typically, a bone block is taken from the patient’s lower jaw and screwed to the bone for osteosynthesis. To accelerate healing, the operated area is additionally compacted with synthetic hydroxyapatite or bone chips, and mandatory covered with a membrane. At the last stage, the mucous membrane is tightly sutured. Using this technology, implantation of implants into the bone is possible only after a few months. In this technique, a piece of bone is taken from a patient in one place to be transplanted to another place. In this case, two wounds form in his mouth at once. In addition, after the bone has healed, he will eventually have another operation to install implants. With osteoplasty with a bone block, the risk of rejection is minimal, since the body perceives the material as its own.
. The basal implantation technique or sinus lift is used when there is insufficient bone volume, in cases where implantation is planned on the upper jaw in its lateral parts. This technology allows simultaneous implantation. Depending on the required thickness of the layer being built up, closed sinus lifting (1-2 mm) and open sinus lifting (more than 2 mm) are used. Upon completion of the closed sinus lift, an implant is immediately installed. At open method implantation is done after a few months.
Stages of bone grafting
The average bone augmentation operation consists of several stages:
Painful sensations after the cessation of anesthesia are not considered a deviation. As after any surgical intervention the patient must feel pain. The body's natural reaction is fever and swelling. But sometimes these signs can indicate incipient inflammation. To relieve pain, the doctor prescribes oral painkillers as well as anti-inflammatory drugs. They take the medications for a week.
Osteoplasty: complications
The effectiveness of bone augmentation during implantation directly depends on how clearly the surgeon followed the surgical technique. Even the slightest deviations from technology can lead to complications. For example, the protective membrane may open through the suture line and then the wound will fester. Insufficient rate of vascularization (vessel formation) during bone block grafting can lead to partial or complete rejection (sequestration) of bone material. In case of suppuration or sequestration, it is necessary to remove both the membrane and bone material from under the gum mucosa. This means that the dental patient will eventually have to undergo another bone grafting procedure. In addition, during the process of introducing them into the tissue, bone blocks can lose up to 50% in volume, and in this case, repeated surgery may also be required. During implantation of an artificial root, the block may come off if it is not sufficiently integrated into its own bone. But it must be said that such cases are rare in modern dental practice.
Today, the attitude towards implantation has become simpler than it was ten years ago. However, the insufficient bone volume for implant placement, which requires bone grafting, changes everything. Many patients categorically refuse additional surgery, preferring other prosthetic methods. However, some techniques make it possible to do without bone grafting even in the most difficult cases. The leading surgeon of the Family Dentistry clinic, a certified implantologist Straumann Young Professional, will tell you more about such techniques.
The Family Dentistry clinic uses the latest foreign developments in this area - implantation is carried out according to the Frankfurt protocol with complete absence teeth, as well as special implants that can be used without first replenishing the volume of the jaw bone in 90% of cases. When a patient has narrow bone, a splitting technique can be used to allow the implant procedure to be performed without bone grafting. Thanks to this technique, the patient receives a finished prosthesis within 3–4 months. While with classical implantation technology with preliminary surgery to increase bone volume, tooth restoration is often delayed for 10–12 months. Thus, the splitting technique avoids invasive procedures such as transplantation of bone blocks taken from other parts of the jaw. In addition, there will be no need for subsequent correction of soft tissues, which is necessary after bone grafting, as a result of which the gum is greatly stretched, which often leads to exposure of the transplanted bone block or implant.
By using special tool, the action of which is based on microvibration (somewhat reminiscent of the effect of ultrasound on tartar), the doctor carefully and non-traumatically makes a small incision in the bone. A special screw implant is installed in it, designed in such a way that it itself splits the bone ridge and increases the total volume of the bone. Unlike surgery using bone blocks, in this situation, specialists perform only one procedure. When plastic surgery with bone blocks is required, at least three operations are required: taking a bone block and transplanting it onto a narrow bone ridge, installing implants after 6-8 months, and also after another 3-4 months - gum surgery. When splitting, all these complex and lengthy manipulations are not necessary.
When implanting using the splitting method, screw implants of a special design are used. They have a cone-shaped body, thanks to which they easily enter the bone, pushing its edges apart like a wedge. However, the wedge is easy to knock out, so the conical shape of the implant is combined with a cylindrical thread profile, which allows it to be firmly fixed in the bone tissue. This unique feature Such implants give doctors the opportunity to install them in narrow bones without bone grafting. They smoothly screw into the gap between the bone walls through a hole measuring only 2 millimeters and do not damage them. In addition, the sharp thread of the screw implants and the wide spaces between the turns of the spiral, through which bone tissue quickly grows, contribute to faster stabilization. Thus, after three, maximum, four months, permanent crowns can be installed.
The technique makes it possible to restore any number of lost teeth. Even when implanting one tooth, the technology allows an incision to be made in such a way as to insert the implant into the bone without damaging the adjacent teeth. But most often a narrow bone occurs in the absence large quantity teeth, so specialists usually install two to four implants on each side.
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Typically, the jawbone is oval in shape. Then, in the process of atrophy, the volume loses only its upper part on the buccal (front) side, while its base remains wide and supports the rest of the bone. In this case, we can safely carry out “splitting” and not be afraid that the bone will break. However, if the ridge lacks thickness along its entire length, or is less than two millimeters, bone grafting is necessary. True, such situations are quite rare, and in these cases doctors are forced to follow the classic path - performing plastic surgery using bone blocks.
Mini-implants can be used as temporary structures or to fix a removable denture. If the prosthesis rests on such implants, they will be rejected. Therefore, when implanting all on four, standard size implants are used.
All-on-4 or All-on-6 techniques allow placement on implants fixed prosthesis. Only a very experienced doctor should install an orthopedic structure, since even a slight error in the calculation can lead to improper distribution of the chewing load and cause rejection of the implants. When implanting “all on four”, the installation of implants can also be carried out using the splitting method. It's simple and effective procedure, which is absolutely safe for the patient and avoids bone tissue build-up.
In this case there are also several options. If the bone height is not enough in the lateral parts of the upper jaw, a sinus lift should be performed. If the bone height is less than 4 mm, we can increase the volume of bone tissue while simultaneously installing a high-quality implant. Thanks to a special micro-thread on the neck, it will take a stable position even in bones measuring 1 millimeter. But if the bone is wide and its height is 4 - 5 millimeters, then you can do without a sinus lift - here they use short implants with strongly protruding threads. Thanks to them large area surface, these short but wide implants can withstand the same load as conventional ones.
It is known that classic root-shaped implants take root in the lower jaw within 2 - 3 months, and in the upper jaw - 4 - 5 months. The timing depends on the “primary stabilization”, that is, how tightly the implant was fixed in the bone during its placement, and on the density of the bone. In hard bone, the implant receives good primary stabilization and can be loaded with a temporary crown after 2–3 months. If the bone is soft, it is necessary to postpone prosthetics for a longer period, otherwise the implant may be rejected.
With the advent of the implantation system with large threads, it became possible to speed up the engraftment time in soft bone, since it increases the area of contact of the implant surface with the bone tissue, and therefore contributes to more durable stabilization. In both soft and hard bone, the healing time of such an implant is 2–3 months.
The price of the procedure consists of the cost of the implant, the doctor’s work, as well as the cost of temporary and permanent prosthetics. Due to the fact that specialists do not perform bone grafting, the price of implantation, of course, decreases, but not much. This technique was created not to save on implant installation, but to avoid additional surgery in cases where this is possible.
For example, if the bone volume is sufficient and its condition is ideal, you can install any modern implant - it will take root and function for a long time. But if it is necessary to carry out a sinus lift simultaneously with implantation, it will be necessary to use implants that are fixed even in 1 - 2 millimeters of bone. But if the bone is narrow, the best option would be to use the splitting technique followed by installation of an implant with a wide thread. Everything is fair here - the doctor does not focus on your wallet, but advises and selects the most optimal treatment plan in accordance with the specific clinical situation.
Screw implants have a lifetime warranty because they are free from any defects: they will not crack, break or become deformed without reason. However, no one can give guarantees about the success of implants in the bone, since this directly depends on the patient’s health condition. If you carefully monitor your oral hygiene and your health, then you can say with confidence that the implant will last you a lifetime and will not be rejected.
The essence of bone tissue augmentation is to restore bone at the site of atrophy. When implanting teeth, there is often a need for similar procedure: in the absence of a tooth, the bone does not receive normal load, gradually dies and after some time becomes so thin that there is literally nowhere to put the pin. To make implantation possible, the bone tissue must be restored. Bone augmentation during dental implantation
There are five main causes of bone atrophy:
Edentia(lack of teeth) is always accompanied by a decrease in bone tissue, which, in turn, leads to a displacement of existing teeth towards the resulting void and malocclusion.
Bone atrophy – serious problem, fraught with extreme unpleasant consequences, such as:
Fortunately, today doctors have many ways to restore lost bone tissue.
Bone grafting is primarily for successful tooth implantation. For reliable fixation of the pin, at least 1 mm of bone tissue is required. Installing an implant into an insufficiently thick and dense bone layer threatens to further accelerate the process of tissue atrophy. Restoration procedures are also indicated for jaw injuries and loss of large amounts of bone tissue as a result of inflammation.
Currently, there are several technologies for restoring lost tissue - so-called osteoplasty:
Each method has its own pros and cons, features and contraindications.
This method was the very first to be developed. Its essence is to transplant a piece of bone into the area of atrophy; Previously, animal bones or donor tissues were used for this purpose, but due to the low survival rate, the use of foreign biological material has now been abandoned.
Today for transplantation is taken patient's own bone material(usually directly from the jaw; in rare cases - from the thigh); This technique ensures easy and almost one hundred percent engraftment. This process is called autotransplantation.
Bone block transplantation IN lately During transplantation, artificial bone substitutes – alloplasts – are increasingly used. They take root almost without problems, are reliable, and their use does not cause complications.
The operation is carried out according to the following scheme:
The advantages of such an operation are reliability and predictability of the result– the layer of bone tissue is quite thick, the survival rate of autotransplantation is very high, and there is practically no risk of rejection.
Among the shortcomings - The transplanted material takes a long time to take root, on average from 6 to 8 months; the possibility of simultaneous installation of an implant is excluded, as this increases the risk of rejection of both the implant itself and the bone block; if there is insufficient integration of the transplanted block with the bone tissue, the side may be torn off from the jaw - the risk of such a complication is small, but still exists.
The method of guided bone regeneration is used in situations where very little time has passed after tooth extraction. It consists of covering the hole extracted tooth a special protective membrane made of biocompatible material.
The point of this procedure is to protect the tooth socket from the growth of soft gum tissue into it, which grows very quickly and penetrates the bone tissue, preventing it from recovering. Under the protection of the membrane, the bone regenerates naturally. Often to speed up the process additional bone tissue is implanted into the socket or allograft.
Guided bone regeneration The advantages of this operation are: low morbidity And low degree stress for the body. Unfortunately, it has many more disadvantages:
Contraindications to the operation are exactly the same as for bone block transplantation - acute infections, blood diseases, cancer, immunodeficiency states, diabetes.
Sinus lifting is a low-traumatic technology for bone tissue restoration. However, it can only be used on the upper jaw, since it involves manipulation of the maxillary sinuses.
With atrophy of the bone tissue of the upper jaw, the space of the nasal sinuses (sinuses) expands due to the decreasing bone. The essence of the sinus lift method is raising the wall of the nasal sinus and the growth of new bone tissue underneath.
Sinus lift surgery is open, in which a hole is made in the wall maxillary sinus, and closed, in which the bone bed itself is prepared. Closed surgery is performed more often, is less traumatic and carries a lower risk of complications. An open sinus lift is performed in extremely rare cases.
In both cases, the technology itself is almost the same. The main stages of the operation are as follows:
After insertion under the membrane, the osteoplastic material must integrate into the bone tissue. If the integration proceeded without problems, a pin is installed in the resulting bone layer.
Sinus lift The advantages of this operation are: low morbidity(at closed sinus lift), reliable engraftment of osteoplastics, low risks of rejection, high quality extended fabric.
The main disadvantages are inability to grow a layer of tissue more than 2 mm. Also, this method is not suitable for restoring a large volume of bone - if two or more teeth are missing (and the corresponding degree of atrophy), sinus lifting is useless.
Contraindications for sinus lifting are the same as for other bone restoration operations, but there are several specific ones: chronic diseases nasopharynx, curvatures and abnormalities of the nasal septum, polyps in the maxillary sinus and frequent runny nose. Smoking habit can also become a serious limitation to the procedure.
As you can see, all three techniques use grafts that replace bone tissue - filling voids, as in a bone graft or sinus lift, or stimulating the growth of your own bone, as in augmentation. There are five types of grafts used in dentistry:
The most effective is the use of pure autograft and a combination of auto- and xenografts. These materials show the best results in terms of speed and quality of engraftment.
Bone atrophy is an unpleasant and unsafe consequence of tooth extraction, fraught with serious complications. It is better to prevent it immediately by installing implants. However, this possibility is not always available. Fortunately, even if bone resorption has already begun, there are technologies for reliable restoration of lost tissue.
Because the amount of available bone, which serves as a support for the implant, is individual for each patient. And it also depends on the different locations of strong and weak areas in the same jaw. Due to inflammatory or degenerative processes in the alveolar bone, areas devoid of teeth are resorbed in both vertical and horizontal directions. Resorption or absorption of bone in the area of missing teeth always results in loss of useful jaw width and height.
Bone anatomical structures such as maxillary sinuses And nasal cavity, and so by default they leave little space for a long implant, and in cases of local osteoporosis, they drive doctors to despair. The statistics of dental implant failures are strongly stimulated by doctors with low level responsibility for the health of patients, scaring them with “terrible bone grafting” and selling implants that are short, narrow and not adapted to overload.
The dense, compact bone provides good and immediate support for the installed implant, while spongy bone sometimes problematic because it cannot provide support to the same extent. On the other hand, dense bone may adversely affect the osseointegration processes of the implant in the future. In highly porous bone, without preliminary strengthening, implants will last no more than two years.
Poor bone quality combined with a low volume of dense bone can be an obstacle to the quality of dental implant placement. Bone quality varies from person to person, and there may be areas of low and low bone density in each jaw and within the same jaw. high density. Changed density is always observed with age and depending on the duration of the period of absence of teeth, as well as after traumatically extracted teeth and chronic inflammation.
All this can be corrected, you just need trust in the treatment and some time.
Our team
As an example of monitoring the doctor's actions, a bone grafting procedure on the upper jaw, called a sinus lift, is ideal.
For example, useful bone, necessary for placing an implant, located under the wall of the maxillary sinus, is divided according to height into 3 groups:
Important! If, during an external examination, a hole, recession, or depression of the gum in the area of the missing tooth or a high gingival arch is visible in comparison with the areas where the teeth remain, our recommendations are not to allow the installation of an implant without reconstructing the height and width of the bone.
Placing an implant into a thin and arched bone at the crown manufacturing stage will result in a narrow or long crown, sharply different from the rest of the teeth. Biomechanically, this solution is short-lived due to inadequate transfer of chewing load from a large crown to a short or narrow implant.
Sincerely, Levin D.V., chief physician
