Annotation
Violation of the continuity of the dentition is associated with the appearance of defects of the dental arch, which should be understood as the absence of 1 to 13 teeth in it. There are small defects when there are no more than 3 teeth, medium ones in the absence of 4 to 6 teeth and large defects when there are no more than 6 teeth. Defects can be located on the upper or lower jaw, being bounded on both sides of the teeth (included) or only on one side (end). The former, in turn, can be located in the anterior, lateral or anterolateral part of the dental arches.
A variety of options for defects of the dental arches was the basis for their classification. The most common is the Kennedy classification.
According to Kennedy, all tooth rows with defects are divided into 4 classes. The first one includes dental arches with double-sided end defects, the second one includes dental arches with one-sided end defects, the third one includes dental arches with defects in the lateral part, and the fourth includes the defects of the anterior part of the dental arch. Each class, except the last, has a subclass.
Examination of the patient
1. Survey.
Examination of the patient begins with a thorough survey. History taking is usually carried out according to the scheme:
1) passport information
2) patient complaints
3) history of the disease
4) patient's life story
2. External examination of the patient
It is made unnoticed during the survey. Attention is drawn to the symmetry of the halves of the face, the height of its lower part, the protrusion of the chin, the lip closing line, the severity of the chin and nasolabial folds, the position of the corners of the mouth, the exposure of the teeth or the alveolar process when talking and smiling.
In the clinic of orthopedic dentistry, the division of the face into three parts has become widespread: upper, middle and lower part. For orthopedic purposes, it is important to distinguish between two sizes of the height of the lower part of the face. In the first case, it is measured with closed teeth, in the second - when the position of relative physiological rest, when the lower jaw is somewhat lowered and a gap appears between the teeth. The first height of the lower part of the face is called occlusal, the second - the height of relative physiological rest. Between them there is a difference, which is strictly individual, as well as the magnitude of separation of teeth with a relative rest of the lower jaw, it is 2-3 mm.
The study of the oral organs.
First of all, determine the degree of mouth opening. Difficult opening of the mouth can take place, as in constriction of the mouth opening, as well as in difficulties of movements of the lower jaw due to muscular or articular contractures. At the same time establish the degree of separation of the dentition when opening the mouth.
Studying the degree of mouth opening, you should pay attention to the nature of the movements of the lower jaw: smoothness, discontinuity, deviations of it to the right or left.
Then study the condition of the oral mucosa. It should begin with the mucous membrane of the cheeks, alveolar processes, soft and hard palate, floor of the mouth and tongue. Carefully inspect the tonsils, the back of the pharynx. Fix attention to the humidity and color of the mucous membrane (pink, pale pink, bluish), its density, bleeding, swelling, sensitivity to irritations. Alveolar ridges should not only be examined, but also probed to detect the sharp protrusions of the roots and teeth, covered with mucous membranes and invisible when viewed.
If necessary, an x-ray should be performed. The method of palpation is mandatory in the study of the region of the sagittal palatal suture. It is important to establish the presence of the palatal roller. Pay attention to the shape of the alveolar process, which is of great importance for fixing the prosthesis.
The mucous membrane covering the alveolar parts of the jaw, hard and soft palate and other areas of the oral cavity, divided into mobile and stationary. The movable shell covers the soft tissues of the oral cavity, which do not have a bone base, and is capable of making excursions while reducing the mimic muscles, movement of the tongue, soft palate and other organs.
The movable mucosa covers the cheeks, lips, floor of the mouth. It has a loose mucous layer of connective tissue and easily folds. The degree of mobility varies widely (from large to insignificant).
The immovable mucosa is devoid of a submucous layer and lies on the periosteum, separated from it by a thin layer of fibrous connective tissue. Its typical locations are the alveolar process, the region of the sagittal suture and palatal roller. However, the concept of "fixed mucosa" is relative. On palpation, it can detect compliance. Especially well this property is expressed in the back third of the arch of the hard palate. This compliance is determined by the presence of vessels in the thickness of the connective layer.
Between the movable and immobile mucous membrane, a vault is formed, called the transitional fold. On the upper jaw, it is formed when the mucous membrane passes from the vestibular surface of the alveolar process to the upper lip and cheek, and in the distal section to the mucous membrane of the winged maxillary fold. On the lower jaw from the vestibular side, it is located at the junction of the mucous membrane of the alveolar part to the lower lip, cheek, and from the lingual side at the junction of the mucous membrane of the alveolar part to the bottom of the oral cavity. Anatomical structures located on the transitional fold, are of great practical importance in prosthetics. In this place is the edge of the base denture. On the eve of the mouth in the upper and lower jaws in the middle line are the frenulum of the lips. One edge of the bridle is attached to the mucous membrane of the slope of the alveolar process, and the other is connected to the transitional fold. Sometimes the fibrous fibers of the bridle can penetrate into the interdental septum between the central incisors and move them apart. The place of its attachment is of great importance for the function of the tongue and the definition of the prosthesis boundaries on the lingual side. On the upper and lower jaws, in the area of premolars, there are cheek bridles that separate the anterior part of the transition fold and vestibule from the lateral divisions. The role of these folds is similar to that described above.
Assessment of the state of the mucous membrane of the prosthetic bed.
Supple main attention is paid to the condition of the mucous membrane of the prosthetic bed. He distinguishes four classes.
First class: there are well-defined alveolar processes on both the upper and lower jaws, covered with a slightly ductile mucous membrane. The palate is also covered with a uniform layer of the mucous membrane, moderately pliable in the back of its third. The natural folds of the mucous membrane (bridle of the lips, cheeks, tongue) on both the upper and lower jaws are sufficiently removed from the apex of the alveolar part. This class of mucous membrane is a convenient support for the prosthesis, including with a metal base.
The second class: the mucous membrane is atrophied, covers the alveolar ridges and the sky with a thin, as if strained layer. The places of attachment of natural folds are located somewhat closer to the top of the alveolar part. Dense and thinned mucous membrane is less convenient for supporting a removable denture, especially with a metal base.
Third class: the alveolar parts and the posterior third of the hard palate are covered with a loosened mucous membrane. This condition of the mucous membrane is often combined with a low alveolar crest. Patients with a similar mucous membrane sometimes need preliminary treatment. After prosthetics, they should especially strictly follow the prosthetic use regimen and be sure to be monitored by a doctor.
The fourth class: the mobile strands of the mucous membrane are arranged longitudinally and are easily displaced with a slight pressure of the impression material. Heavy duty can be infringed, which makes it difficult or impossible to use the prosthesis. Such folds are observed mainly in the lower jaw, mainly in the absence of the alveolar part. The alveolar edge with a dangling soft ridge belongs to the same type. Prosthetics in this case sometimes become possible only after its removal.
Based on the varying degrees of ductility of the mucous membrane, Lund identifies four zones in the hard sky:
1. the area of the sagittal suture,
2. alveolar process,
3. area of transverse folds,
4. back third
In addition to examining and palpating the organs of the oral cavity, according to indications, other types of research are carried out (radiography of the alveolar parts, joints, graphic recordings of movements of the lower jaw, recording of the incisal and articular paths, etc.).
Special preparation for prosthetics with complete loss of teeth includes a large number of operations, the purpose of which is determined by the specific clinical picture, for the convenience of their study, they are distinguished:
1) Correction of the alveolar part
2) alveolar ridge plastics
3) the creation of artificial wells
4) replanting of the metal subperiosteal framework
5) preparation of a hard palate
6) elimination of cords and scars of the mucous membrane of the prosthetic bed
7) deepening the vestibule of the mouth and floor of the mouth
Special orthopedic preparation of the oral cavity for prosthetics:
1) alignment of the occlusal surface by increasing the alveolar height
2) alignment of the occlusal surface by shortening the teeth