At the first type of the alveolar process and uniformly slightly atrophied. At this early rounded alveolar ridge is a good basis for the prosthesis and it restricts the freedom of movement in the direction of the displacement. The points of attachment of muscles and folds of mucous membrane located at the base of the alveolar bone. This type of jaw observed in that case, if the teeth are removed at the same time and atrophy of the alveolar process is slow. It is most convenient for the prosthesis, although relatively rare.
The second type is characterized by a significant expression, but uniform atrophy of the alveolar bone. Alveolar ridge barely rises above the bottom of the oral cavity, representing in the anterior narrow, sometimes sharp as a knife, education is of little use under the base for the prosthesis. The insertions of the muscles are almost at the level of the ridge. This type of lower edentulous jaw is very difficult to obtain a stable prosthesis and functional result, since there are no conditions for anatomical retention, and the high position of the points of attachment of muscles in their reduction leads to a shift in the prosthesis to his bed. Use of a prosthesis with the often painful because of the sharp edge of the internal oblique line and in some cases, success is achieved only prosthetics after smoothing.
The third type is characterized by severe alveolar atrophy of alveolar bone in the lateral parts with relative preservation of alveolar bone in the anterior part. This type of alveolar bone occurs with early removal of posterior teeth. It is favourable for the prosthesis, because in between the sides of the external and internal oblique lines are flat, almost concave surfaces are free from points of attachment of muscles, and the presence of alveolar bone in the anterior region of the displacement of the prosthesis prevents him in the anterioposterior direction.
In the fourth type of atrophy of the alveolar process is most marked in front with relative preservation of it in the sides of the lower jaw. As a result, the prosthesis loses support in the anterior and slides forward. Assessment of the mucous membrane of edentulous jaws. Changes that develop in the mouth after tooth extraction capture not only the alveolar process, and the mucous membrane covering them, and the hard palate. They can be expressed in the form of atrophy, wrinkling, change the position of the fold transition to the alveolar ridge. The nature and extent of these changes are related not only to the loss of teeth, but also the causes which led to their removal. General and local diseases, age-related changes also affect the nature and extent of the restructuring of the mucous membrane after tooth extraction. Knowledge of the characteristics of tissue covering the prosthetic area, is of great importance both to select the method of prosthetics, and to prevent harmful effects of the prosthesis on the supporting tissue.
Supple focus draws on the state of mucous membrane and releases 4 classes. At the first class, both on the upper and lower jaw have a pronounced alveolar ridge, covered slightly pliable mucosa. The sky is also covered with an even layer of the mucous membrane, uniformly supple in the posterior third. Natural folds of mucous membrane (lip, cheek and bridle cheek bands) as the upper and lower jaw are far enough from the top of the alveolar bone. This class is a convenient mucosal support for the prosthesis, including a metal base. The second class is characterized by atrophied mucous membrane covering the alveolar process and the sky as thin as a strained layer. The insertions of natural folds are located closer to the top of the alveolar process than first class. Dense and thinned mucosa is less convenient to support the denture, especially with a metal base. In the third class of the alveolar process and the posterior third of the hard palate is covered loosened mucosa. Such a condition often found lining the low alveolar ridge. Patients with this mucous sometimes require preliminary treatment. After prosthesis should adhere strictly to the use of prosthesis and always under medical supervision. Fourth grade is characterized by moving tissues of the mucous membrane, located longitudinally and easily slips when slightly off impression material. Strands be constrained by making it difficult or impossible to completely use a prosthesis. These folds are observed mainly in the lower jaw, mainly in the absence of alveolar bone. The same type of alveolar bone is to "hang out" soft ridge. Sometimes the prosthesis can be made only after the removal of the ridge. Mucosal pliability, as seen from the classification Supple, is of great practical importance.
Based on the varying degrees of flexibility of the mucous membrane, Lund allocates hard palate 4 areas:
1. area of the sagittal suture;
2. alveolar bone;
3. portion of the hard palate in the transverse folds;
4. posterior third of the hard palate.
The mucosa of the first zone is thin, has no submucosa. Suppleness of her minuscule. This site is named Lund medial (middle) of the fibrous zone. The second zone captures the alveolar bone and is also covered by mucous membrane, and almost devoid of the submucosal layer. Is peripheral fibrous zone. The third zone is covered with mucous membrane, which has a high degree of compliance. The fourth area - the back third of the hard palate, a submucosal layer rich in mucous glands and contains little fat. This layer is soft, springy in the vertical direction has the highest degree of compliance and called glandular area. Most researchers explain yielding mucosa of the hard palate and alveolar structural features of the submucosal layer, in particular, located in its fiber and oil glands. Different point of view, we adhere to, linking vertical compliance of mucosal surfaces with a thick jaw bones submucosal vasculature. It was filled with their ability to rapidly emptied and as quickly fill with blood can create conditions for reducing the volume of tissue. Lots mucosa of the hard palate with extensive vascular fields, has therefore, as it were spring properties, called buffer zones. The histological and topographical studies (V.S. Zolotkov) found that the mucous membrane covering the alveolar process and part of the hard palate to the sagittal suture, has small vascular fields and buffer properties because almost none. In areas of the mucous membrane located between the base of the alveolar process and the middle zone are dense vascular field, which increases the density of blood vessels in the direction of the line "A". So that the buffering capacity of the mucous membranes of the hard palate in the direction of the line "A" is also increasing. Pliability mucosa of the hard palate studied in detail V.I. Kulazhenko by electron-vacuum apparatus. He found that it is in the range of 0.5 to 2 mm. These V.I. Kulazhenko point of compliance mucosa of the hard palate with the topography of the same buffer zones on E.I.Gavrilov.
Buffering capacity of the mucosa of the upper jaw prosthetic field in life change dramatically, due to changes in blood vessels under the influence of age, metabolic, infectious and other diseases. The state of the vessels of envy not only yielding mucosal surfaces of the hard palate, but the nature of its response to the effects of the prosthesis. In the origin of changes in the mucosa, atrophy of the alveolar process, is often observed in long-term use of prosthetic vessels play a major role.
Topic 84.1. Benchmarking to build the bite.
GENERAL PURPOSE: students to explore on their own clinical techniques determine central occlusion with complete loss of teeth, and benchmarking for constructing the elements bite.
- Determine the height of the lower part of the face (the height of the bite);
- Determination of the position of physiological rest;
- Determination of the occlusal (prosthetic) plane;
- Benchmarking for constructing the elements bite. Methods
ACADEMIC INFORMATION NECESSARY FOR THE STUDY OF THE TOPIC:
1. Prosthetic treatment of the edentulous patient. Fourth edition. R.Basker, J.Davenport. Blackwell. 2002 – 316 p.
2. Complete Denture. Manual. Robert W. Loney, DMD, MS. 2009.- 99 p.
ORGANIZATIONAL STRUCTURE OF THE practical CLASSES
Clinical observations suggest that of all the factors that determine the success of orthopedic treatment in general, and related to the conservation of the health and proper functioning of tissues and facial dentoalveolar system, nothing will affect the performance of a full prosthesis is the correct definition of the central occlusion. Long-existing disorders in relation jaw caused by a lower height of the bite, lateral shear jaw and excessive unjustified lifting height of bite disturb the harmony in the maxillofacial system; create unfavorable conditions for normal function of all its elements. Such conditions may lead to pathological changes in the temporomandibular jaw joint, in the masticatory muscles and periodontal teeth. By reducing the height of the bite is atony masticatory muscles and force reductions, there is biting his cheeks and lips, and in advanced cases - the development of the syndrome of bones. When excessive picked in prosthetic height of occlusion masticatory muscles tone and strength reductions and increases bone foundation prosthetic field under intense pressure, it shows the development of clinically congestion around the alveolar ridge, and eventually leads to premature and excessive to atrophy. In literature there are many different definitions of the central occlusal position of the lower jaw to the upper as well as its terminology symbols, namely: Central occlusion, central location, central relationship, dorsal position, functional central and habitual occlusal position. In Soviet literature often uses the terms "centric" and "central jaw relationships. «Centric definition is usually given on the basis of the provisions of the joint heads of the articular fossa, states chewing muscles and the relationship of dentition during closure. E.I.Gavrilov (1968) understands the centric occlusion of dentition with the maximum number of points of contact. The average person line coincides with the line drawn between the incisors; joint head is positioned on the slope of the articular tubercles at their base. Actually masseter and temporalis muscles on both sides contract simultaneously and uniformly. L.V. Ilyina-Markosian (1973) in addition to the central allocates more and habitual occlusion, characterized by different offsets the lower jaw, with which it is impossible to coordinate the work of chewing and facial muscles and temporomandibular jaw joint.
S. Walsh (1951) linked the definition of centric relation with intermaxillary relationship, in which all the elements that make up the chewing system, namely, teeth, joints and muscles that are in harmony.
N. Brill (1959) distinguished the following provisions of the mandible in the sagittal, vertical and horizontal planes: occlusal position at which the maximum observed fissure-cusps contact motion from rest in the "occlusion" position - includes, by author, sliding elements, "copular position"- retruziv rearmost position "from which the lower jaw can be displaced distally, as her movements are limited lateral ligaments of the joint, "copular position" according to the authors of these studies, coincides with occlusion only 10% of the patients, in others, it is 0.5-1 mm posterior to "occlusal position", the authors also introduce the concept of "muscle position," meaning by it the first contact of the teeth and dental arches in reflex muscle contraction, such as swallowing (in most patients with preserved mounds of teeth "muscle to" match "occlusion" and cusps interdigitation).
N. Posselt (1962) reported that in 88% of cases in the examined patients retruziv and occlusion of the lower jaw are not the same, based on the maxillary central ratio specified by defined as a small area in the space within which the contact between the upper and lower teeth are preserved during chewing and swallowing. Summarizing these theoretical data, we must conclude that the central jaw relationships can be considered only if there are signs of it all together: the optimal vertical height of the lower part of the face, uniform and simultaneous reduction of masseter and temporalis muscles on both sides, a certain state of the articular heads in the articular fossa (articular head adjacent to the slope of the articular tubercle), and finally, well-defined spatial position of the lower jaw to the upper four-Lust and skull. In connection with such views, the term "central jaw relationships" is more inclusive and accurate than the term "central occlusion." In addition, it is more acceptable to the prosthetics clinic patients with complete loss of teeth, as in such cases is determined, above all, it is the ratio of maxillary and not occlusion. The shortest and in connection with its main clinical features of the central relationship can also be described as the back (retruziv) of the lower jaw at the optimum height of the lower face of department, from which easily, without effort, can be made lateral movements. Disclaimer the information contained in the statement - "from which can be freely produced lateral movement" - provided that there are other provisions of the lower jaw, as follows: the rear position. As emphasized by Herbst (1954), for maximum rear, some enforced location of the mandible requires active muscle tension, and for this reason it cannot be regarded as a starting "start" for the natural movements of the lower jaw. Knowledge of the basic physiology of the central position of the lower jaw in the space and in relation to the joints and muscles should be of great help in the reconstruction of the central occlusion, bite patient forms, and to ensure contact between the artificial teeth of the upper and lower jaw during chewing.