Jaws

JAWS. The paired upper jaw bone (maxilla) is the lightest, most fragile pneumatic bone and is firmly fused by sutures with most of the bones of the facial skeleton. Its palatine process is connected to the palate by a special type of synarthrosis (harmonia). The lower jaw bone (mandibula), on the contrary, is the heaviest, strongest, and most compact bone and is articulated with the glenoid fossa of the temporal bone by means of a diarthrosis. The jaw together with the teeth and corresponding muscles forms the masticatory apparatus and the bony framework of the vestibule of the respiratory and digestive tracts, which plays a significant role in the act of articulate speech and singing in humans. Upper jaw. The maxilla occupies the central part of the facial skeleton and with its frontal process abuts against the anterior part of the cerebral skull. With its three surfaces-orbital, nasal, and palatal-it faces the cavities of the orbit, nose, and mouth, while its facial and infratemporal surfaces open onto the surface of the face and into the infratemporal and temporal fossae. The five listed surfaces of its body form an extensive air-containing cavity (the Highmor cave or maxillary sinus-antrum Highmori, s. sinus maxillaris), lined with mucous membrane and communicating with the middle nasal passage (see Highmor cavity). In addition to the body (corpus maxillae), four processes diverging in various directions participate in the formation of the maxilla: frontal (processus frontalis), zygomatic process (processus zygomaticus), dental, or alveolar process (proc. dentalis, s. alveolaris), and the palatal process that overhangs the oral cavity.

Medially it borders with the lacrimal bone, the lamina papyracea of the ethmoid, and the orbital process of the palatine bone; with its posterolateral edge it participates in the formation of the margins of the inferior orbital fissure; with its lateral, serrated edge it is connected by a suture with a similar edge of the orbital process of the zygomatic bone. The surface of the wall is smooth, sloping, and is traversed over most of its extent by the infraorbital groove (sulcus infraorbitalis), which turns into a canal (canalis infraorbitalis), opening by a large infraorbital foramen on the anterior surface of the body of the maxilla; the canal serves for the passage of vessels and nerves of the same name from the second branch of the trigeminal nerve (a. et v. infraorbitales, n. maxillaris). An extremely thin wall of the canal separates it from the Highmor cavity located beneath it, which practically plays an extremely important role. With its infraorbital margin (margo infraorbitalis), the upper jaw participates in the formation of the lower wall of the entrance to the orbit (aditus orbitae). Its anterior surface is called the facial (Fig. 2), buccal, or anterior surface (superficies facialis, facies malaris, s. anterior). This surface is uneven-with a significant depression in the middle, the so-called canine fossa (fossa canina), representing racial, age, sex, and individual differences. Closer to its upper edge opens the facial, or external, opening of the infraorbital canal (foramen infraorbitale), through which, spreading in a small goose's foot (pes anserinus minor), the n. infraorbitalis emerges.

The floor of the canine fossa, from which the muscle of the same name (m. caninus) originates, is rough and externally merges with the zygomatic process of the maxilla. Downward the anterior wall imperceptibly passes into the anterior surface of the alveolar process and, like the latter, bears a series of alveolar elevations (juga alveolaria), corresponding to the relief of the roots of the anterior group of teeth (incisors, canines, and premolars). The walls of these elevations are thinned, often grooved, and are easily traumatized during tooth extraction. Its medial margin participates in delimiting the piriform aperture of the nose by means of a deep incision (incisura nasalis); posteriorly the anterior surface of the maxilla borders with the posterior infratemporal surface and is separated from the latter by the zygomaticoalveolar crest (crista zygomatico-alveolaris), which begins at the first molar and above merges with the zygomatic process. Posterior to the just described crest extends the posterior, or infratemporal, surface of the body of the upper jaw (facies infratemporalis), ending posteriorly with a tubercle (tuber maxillare). The entire posterolateral surface is studded with small openings leading into canals through which the superior posterior dental nerves (nn. dentales super, poster.) enter for the group of posterior teeth. The posterior surface quite steeply turns upward into the smooth orbital surface and anteriorly into the smooth nasal surface. The upper medial end bears a small rough palatal platform (trigonum palatinum) for articulation with the orbital process of the palatine bone (processus orbitalis ossis palatini), which participates in the formation of the inferomedial wall of the orbit. Facing inward toward the nasal cavity.

Above and in front, the edge of the opening closely approaches the inner surface of the frontal process and is separated from it by a deep groove, which turns into the so-called lacrimal groove (sulcus lacrimalis), serving for the passage of the lacrimal duct from the orbit into the nasal cavity (ductus lacrimalis). The entire inner surface of the frontal process appears markedly rough and is traversed by two ridges, one above the other, serving for connection with the inferior concha of the ethmoid bone and the free nasal concha. These are the ethmoidal and conchal ridges (cristae ethmoidalis et conchalis), below which the nasal surface of the body merges with the base of the frontal process into a smooth area extending to the piriform aperture and forming part of the lateral wall of the inferior nasal meatus (meatus nasi inf.). Below, the palatine process (processus palatinus) projects, the upper surface of which is smooth; the posterior part of the nasal surface of the body of the maxilla, merging with the edge of the maxillary tuberosity (tuber maxillare), forms a rough area connecting with the perpendicular plate of the palatine bone. Along the edge of junction, widening below, runs the pterygo-palatine groove (sulcus pterygo-palatinus), which on the complete skull is converted into a canal of the same name due to the union of three grooves of the same name—of the maxillary, sphenoid, and palatine bones. Of the four processes of the maxilla, the frontal process is directed upward. Its upper edge is notched and serves for connection with the nasal part of the frontal bone. The outer surface is smooth and its thin anterior edge connects with the nasal bone, while its base, merging with the body, takes part in forming the upper parts of the boundary of the piriform aperture. Above, closer to the medial edge, descends downward the lacrimal crest (crista lacrimalis), bordering the lacrimal groove located medially (sulcus lacrimalis). The wide notch running along the lateral lacrimal edge (margo lacrimalis) is called the lacrimal notch (incisura lacrimalis) and on the complete skull is filled by the lacrimal bone (os lacrimale), which takes part in forming the above-mentioned nasolacrimal canal. The massive zygomatic process begins from the upper edge of the facial surface and extends outward and backward, where, by suture with the zygomatic bone, it forms together with it and with the zygomatic process of the temporal bone the zygomatic arch (arcus zygomaticus). The palatine process appears massive and contains a considerable layer of spongy bone substance, which decreases as it extends backward. Located frontally between the oral and nasal cavities, it takes part in forming the anterior parts of the hard palate. On the inner notched edge is seen the paired part of the incisive groove (sulcus incisivus). Its upper, nasal surface is smooth; the lower, oral surface, on the contrary, is rough and has a series of palatine grooves (sulci palatini), in which vessels and nerves are located. At the anteromedial edge is visible the part of the incisive foramen (foramen incisivum), which represents the external opening of the canal of the same name (canalis incisivus). The incisive canal is fully represented on the complete skull and is formed from two semicanals or grooves of the same name. Through the canal opening descends into the oral cavity the incisive nerve (n. incisivus, s. naso-palatinus Scarpae). The alveolar process borders below the body of the maxilla, merging and imperceptibly passing into its facial and infratemporal surfaces. Below it merges with the palatine process of the same bone and with the horizontal plate of the palatine bone. On it three surfaces are distinguished: the outer, or buccal; the inner, or palatal-oral; and the lower, properly alveolar, occupied by the alveoli of the teeth and built mainly of spongy bone substance, separating the outer and inner compact plates. The amount of spongy substance in the posterior parts increases, and the plates diverge widely from each other. The lower surface is also called the alveolar border (limbus alveolaris) and, by means of transversely and longitudinally located intra- and interalveolar septa (septa intra- et interalveolaria), forms in adults eight sockets of varying structure, or alveoli (alveolae dentales), into which the roots of the teeth are firmly implanted (see Teeth). The shape and size of the alveoli are determined by the size, shape, and number of tooth roots in the jaws. Of the two plates, the anterior one is thinner, which is why during tooth extraction the first movement with forceps should be directed precisely toward this wall. On the floor of the sockets can be seen a series of small openings for vessels and nerves. The maxilla develops in fetal life according to some authors from six, according to others (Beclard, Sappey, Köbiker)—from five points of ossification, which on the sixth month merge, forming a single bone. During its ontogenetic development it grows extremely vigorously, sharply changes its shape, and finally is completed in the adult state after the eruption of the wisdom teeth. The part of the dental process corresponding to the incisors in many animals throughout life, and in man during the fetal period of development, represents a separate bone—the so-called incisive part (pars incisiva, os incisivum) or intermaxillary bone (os inter-maxillare, praemaxilla). On young skulls traces of its incomplete fusion with the palatine process can still be seen. Albrecht and Meyer (Albrecht, Meyer) believe that os intermaxillare consists of two separate bones corresponding to the I and II incisors; these bones normally fuse very early. Pathological non-fusion of them is usually found in a malformation known as hare-lip (see). Variations of the maxilla. The infraorbital opening is most often located 1 cm below the edge of the orbit, but cases of its location 4-12 mm from this edge may be encountered; the shape of the opening also varies: sometimes round, sometimes oval-slit-shaped; instead of one opening there may be many (Gruber describes a case with 5 openings; Testut).

The mandible consists of a body and two branches diverging laterally and upward (fig. 3, 4). In the body, consisting of two compact plates with intermediate spongy substance, the base and the alveolar border are distinguished. The base (basis) is the strongest and most massive part of the entire bone. On the anterior surface of the base projects the mental protuberance (protuberantia mentalis); laterally from it along the very lower edge are paired mental tubercles (tuberculum mentale), lateral and above which lie the mental foramina (for. mentale), serving for the exit of the mental artery and nerve. Laterally from them, directed upward toward the coronoid process, rises the external oblique line (linea obliqua ext.), corresponding to the most massive part of the outer compact, extremely strong plate. The alveolar process, as in the upper jaw, contains 8 sockets arranged archwise along the alveolar border. On the anterior surface the already described alveolar ridges (juga alveolaria) are clearly noticeable. The interalveolar septa (septa interalveolaria) consist of spongy substance, forming a considerable accumulation in the mandible. Through it passes the mandibular canal (canalis mandibulae), beginning on the inner surface of the body with the opening of the mental canal (for. mandibulare).

On the inside, the internal mental spine (spina mentalis interna) rises, serving as the attachment point for the fibers of the mylohyoid and genioglossus muscles (m. genio-hyoideus, m. genio-glossus). Lateral to the spine is a small fossa (fossa digastrica) for the digastric muscle (m. digastricus). Along almost the entire length of the inner surface of the body runs the internal oblique, or mandibular line (linea obliqua interna, s. mylo-hyoidea), to which the fibers of the mylohyoid and glossopharyngeus muscles are attached. Below extends a sulcus of the same name (sulcus mylo-hyoideus), formed by the mylohyoid nerve and artery passing through here. Below the mentioned line, near the angle of the lower jaw, is an oval depressed fossa (fossa submandibularis), representing the impression of the submandibular gland (gl. submandibularis) located here, and above it, closer to the midline, a less significant depression of the sublingual gland (gl. sublingualis). The ascending branch (ramus ascendens), starting from the border of the angles of the lower jaw, has two surfaces—external and internal—and at its top ends with two processes—the condylar (proc. condyloideus) and the coronoid (proc. coronoideus). The articular, or condylar process, with the help of an oval flattened head (capitulum mandibulae), articulates with the corresponding fossa of the temporal bone. Below the head is a narrowing—the neck (collum mandibulae), on the medial side of which is a small pterygoid fossa (fossa pterygoidea) for the attachment of the fibers of the lateral pterygoid muscle. To the neck, tightly fusing with it, is attached the capsular ligament and the lower end of one of the ligaments strengthening the temporomandibular joint, the so-called lig. temporo-mandibulare, which begins at the base of the zygomatic process of the upper jaw above the articular tubercle. Even lower, merging with the upper end of the sulci mylo-hyoidei, is the internal opening of the mandibular canal (foramen mandibulare), covered by a small bony plate called the lingula, to which another ligament strengthening the temporomandibular joint is attached (lig. spheno-maxillare), starting from the angular spine of the sphenoid bone and temporal bone. Below the opening, the entire medial surface of the ascending branch in the region of the angle is rough (tuberositas pterygoidea). Here the medial pterygoid muscle is attached; on the lateral surface the roughness is more pronounced due to the large mass of the masticatory muscle (m. masseter) attached here, which gives the name to the roughness itself (tuberositas masseterica). Passing through the bone mass, the mandibular canal (canalis alveol. infer.) serves for the passage of the homonymous arteries, veins, and nerves (n., a. et v. mandibulares); along the entire course of the canal, the finest canals branch off, going to the dental alveoli, for the corresponding dental arteries and nerves. The coronoid process varies in size and width of its base, which is related to the type of structure of the human jaw apparatus and thus to the development of the temporal muscle attached to it. The two bony plates diverging from the base of the coronoid process to the external oblique line and to the alveolar edge form a significant retromolar platform (fossa retromolaris), in the region of which is the buccal crest (crista buccinatoria), serving as the attachment point for the homonymous muscle. The mandibular bone develops in uterine life from two halves having independent ossification points. Connected along the median line by connective tissue, both halves unite into a single bone by the end of the first year due to the ossification of the connective tissue layer. The "mandibulare," from which the lower jaw is formed in humans, according to Günter, is laid down as a massive cartilaginous arch, the so-called Meckel's cartilage (cartilago Meckeli), on which in its anterior segment the proper lower jaw, the covering bone called "dentale," develops. Meckel's cartilage disappears with age, except for the upper posterior end, where the malleus and incus develop. By the end of pregnancy, sometimes already after birth, in the region of the median suture, several (up to 4) small mental bones (ossicula mentalia) can be found, representing the anterior ossification areas in Meckel's cartilage, which later fuse with the mandibular bone and participate in the formation of the external mental prominence. Throughout the entire intrauterine and the first years of extrauterine life, the lower jaw is poorly developed in relation to the base of the body, while the alveolar edge with the tooth germs laid in it is already well expressed. For this reason, the foramen mentale, usually located in the middle of the body's length, lies very close to the lower edge of the bone. Only at the age of 6-7 years does the jaw take on the form and structure characteristic of adults. Having developed, the base of the body remains throughout life, while the individual sockets, and in old age often the entire alveolar edge with the loss of teeth, are completely resorbed, as a result of which the foramen mentale in the elderly moves to the upper edge of the bone, which sharply decreases in height, due to which the face of the elderly again approaches the round shape characteristic of childhood.

H. Melik-Pashaev.

Pathology of the jaws. Inflammatory processes occupy a dominant place in the pathology of the jaws. The starting point for most of them is gangrenous and pulpless teeth, from which infection penetrates through the root canal beyond the apex, causing reactive inflammation in the tissues surrounding the tooth, so-called paradentitis (see Peridentitis). Siegmund proved that a significant portion of treated teeth have inflammatory processes on their roots; these processes can either take the form of limited, proliferative inflammation—a root granuloma (see Granulomas, granulomatosis, dental granuloma), which slowly destroys the surrounding bone walls and clinically manifests only during exacerbations when exudative phenomena come to the forefront, or the process from the very beginning takes the character of acute inflammation, infiltrating and dissolving the surrounding tissues and ending in the formation of the so-called alveolar abscess (see), which is an osteomyelitis of the alveolar process. With the evacuation of pus—either through an incision or spontaneous opening of the abscess—the infiltration of surrounding tissues decreases, acute phenomena subside, but if the diseased tooth is not extracted, the process passes into a chronic state, a fistula forms through which pus is discharged from the periapical focus, maintained by infection from the diseased tooth. Dental fistulas (osteomyelitis, osteitis, periostitis of dental alveoli). Prolonged purulent inflammation, clinically manifested in the form of fistulas, leads to necrosis of the bone walls and floor of the alveoli, often also affecting the body of the jaw. This can be easily verified during surgical interventions, when in the presence of fistulas significant dissolution of bone tissue is found with the formation of osteophytes (fig. 5). Depending on the direction in which pus makes its way and the place where the opening of the dental fistula is located, two main groups of fistulas are distinguished: 1) gingival fistulas and 2) cutaneous fistulas. Gingival fistulas open most often in the vestibule of the mouth at the level of the apex of the causative tooth, the fistula opening is surrounded by a small hyperemic ridge, and from the opening a small tubercle of granulation tissue often protrudes. The openings of fistulas originating from the palatal roots of molars and from the lateral incisors of the upper jaw open on the palatal side; the direction of fistulas from the lateral incisors is explained by the deviation of the apex of the root toward the palate; Lartschneider attributes importance to the presence on the palatal side of the alveoli of these teeth of a large number of emissaries remaining at the site of the suture of the intermaxillary bone. The starting point for cutaneous (facial) fistulas is mainly paradentitic teeth of the lower jaw. Bock, who collected material from 758 fistulas, established that of 400 fistulas affecting the upper jaw, there were only 19 facial fistulas (about 5% in relation to gingival fistulas), and of 358 fistulas of the lower jaw, there were 150 facial ones (about 70% in relation to gingival fistulas). Of this total number of fistulas, there were only 14 palatal and 4 lingual. Relatively large percentages among facial fistulas are occupied by chin fistulas from foci around the incisors and canines of the lower jaw. Cases of fistulas on the skin of the anterior chest surface, originating from the apices of teeth, have been described. The cause of a fistula may be an externally intact tooth with a necrotically disintegrated pulp due to trauma accompanied by rupture of the pulp capillaries. These traumas sometimes have a professional character, for example, in seamstresses, upholsterers. Clinically and patho-anatomically, dental fistulas should be considered as a symptom of inflammation of the tissues surrounding the tooth, including bone tissue and periosteum, i.e., as a symptom of limited chronic osteomyelitis of the alveolus. Therapy. The main task in the treatment of dental fistulas is the removal of the focus. If the guilty tooth is in any way valuable for the chewing apparatus, then for its preservation the operation of root apex resection is used, mainly on the front 10 teeth (see Peridentitis, treatment). For facial fistulas, it is necessary to accurately determine (X-ray) the starting point and carefully remove the focus; if the fistula does not close after this, then it must be cleaned from the opening side, preferably the entire fistulous tract is excised and the wound is closed plastically. Osteomyelitis of the jaws (osteitis, periostitis of the jaws) is a frequent disease, occupying one of the first places among osteomyelitis of other bones. Thus, of 746 osteomyelitis cases that passed through the surgical department of the Obukhovskaya hospital, 279 fell on osteomyelitis of the jaws (Vvedensky). In terms of etiology, osteomyelitis of the jaws differs from osteomyelitis of other bones in that mixed infection predominates in them and anaerobic infection is more common than in osteomyelitis of other bones. Tuberculosis, syphilis, actinomycosis cause specific osteomyelitis of the jaws. The so-called phosphorus necrosis of the jaws and osteitis in turners processing pearl, as well as necrosis of jaw bones from arsenic, described in former times, should be considered as osteomyelitis associated with professional harm. In terms of pathogenesis, it should be emphasized that in the vast majority of cases, osteomyelitis of the jaws develops on the basis of paradentitis. Paradentitis as a rule is the first stage in the development of odontogenic osteomyelitis of the jaws, and between them and osteomyelitis, neither clinically nor patho-anatomically can a sharp boundary be drawn, since they are actually connected by the commonality of etiological and pathogenetic factors. Often the cause lies in the so-called difficult eruption of the wisdom tooth (dentitio difficilis). The essence of this disease is the ulceration of the area of mucous membrane covering the crown of the wisdom tooth (pericoronitis), which can be caused by pressure from the antagonist, the upper wisdom tooth, or by contamination with decomposed food residues that have penetrated into the gingival pocket. The inflammation arising on the basis of these phenomena is the cause of a series of complications in the surrounding soft tissues, spreading from them to the periosteum and bone; if the process cannot be promptly controlled, it can be the cause of severe osteomyelitis of the lower jaw. Depending on the routes of infection penetration, odontogenic and hematogenous osteomyelitis are distinguished. The lower jaw is affected by osteomyelitis much more often than the upper. Thus, according to Vvedensky, of 279 osteomyelitis cases of the jaws, 245 fell on the lower jaw and 34 on the upper; according to Ponomarev, of 250 jaw osteomyelitis cases, 225 were on the lower jaw and 25 on the upper; similar data is also provided by Lukomsky. This difference in the frequency of lesions of the upper and lower jaws is explained by the difference in their anatomical structure; the external and internal oblique lines thicken the wall of the lower jaw, the density and thickness of which reach a maximum in the area of the 2nd and 3rd molars; with apical inflammatory processes in this area, pus has difficulty making its way through the thickness of the cortical walls, and it is directed deep into the bone—into the spongy bone, which explains why the most severe osteomyelitis with the formation of large sequestra occur in this area. The upper jaw is pneumatized, its walls are thin, porous; in acute paradentitis it quickly dissolves, giving an outlet for pus; this explains the rarer occurrence of osteomyelitis of the upper jaw. Clinical picture of odontogenic osteomyelitis. The disease begins acutely: with chills, high temperature—up to 40°; unlike acute paradentitis, here the guilty tooth as well as a number of neighboring teeth quickly become loose, pain on pressure along the bone beyond the infiltrate appears; an important diagnostic sign is Vincent's symptom—hypesthesia in the chin area. Not having a bone marrow canal, the lower jaw, with infection originating from apical paradentitis, is involved in its entirety in the process, which spreads from the center (floor of the alveolus) to the periphery; the starting point of inflammation is the periosteum of the tooth, the close connection of which with the alveolus ensures the rapid transition of the process to it; through it, especially through the interdental septa, consisting of spongy tissue, the process penetrates deep into the jaw where the elements of bone marrow substance lie, and from here inflammation spreads to the cortical plates, to the periosteum of the jaw and to the surrounding soft tissues; trismus appears, indicating infiltration of the masticatory or medial pterygoid muscle, increasing as the inflammatory infiltration increases. Depending on the extent of jaw involvement, limited and diffuse forms of osteomyelitis are distinguished. The latter is accompanied by severe general septic phenomena. Consciousness becomes clouded, delirium sets in, the pulse is rapid, high temperature gives only small remissions. The strength of the patient quickly falls, his life is in danger. Complications. The most frequent complications of osteomyelitis are perimaxillary phlegmons. The clinical course of them depends on the localization; phlegmons of the temporal region and pterygoid fossa are especially dangerous; on the lower jaw—retromandibular phlegmons and phlegmons of the floor of the mouth (see Angina Ludovici). Infection from these areas can be carried to the cranial sinuses via the vessels (thrombophlebitis) or can descend into the mediastinum. Therapy of acute osteomyelitis of the jaws.

When the cause of acute osteomyelitis is a periodontal tooth, it as a source of infection must be removed; only in those cases where removal of the tooth is associated with significant trauma, e.g., in semi-impacted wisdom teeth, in deeply fractured roots, extraction must be avoided. In pericoronitis, thorough tamponade of the pocket under the hood with an iodoform gauze strip is necessary; with this simple measure, it is often possible to arrest the process. In septic forms of osteomyelitis complicated by phlegmon, the latter must be opened without waiting for fluctuation; on the upper jaw, the incision can be made in the vestibule of the mouth along the transitional fold. To open submandibular and retromandibular phlegmons, the incision is made along the edge of the jaw, retreating from it by the width of a finger, from the angle of the jaw forward 4-5 cm; the skin, subcutaneous tissue, platysma and fascia are cut, bluntly penetrating in the medial direction; from this incision, the bed of the submandibular salivary gland and the bed of the sublingual gland can be examined, and it is also possible to reach the parapharyngeal space. Despite the fact that the teeth in the area of jaw lesion become loose and as if hang only on the gum, their hasty removal should be avoided. Even severely loosened teeth, with a favorable course of the disease, become firm again. Along with local surgical treatment, it is necessary to monitor the general condition of the body. A vigorous fight against septic phenomena is necessary (see Sepsis). When acute phenomena subside, the process takes a chronic course. The more intense the acute period proceeded, the more extensive the area of phlegmonous inflammation, the greater the danger of necrosis of the jaw bone. Most often, extensive sequestration affects the area of the lower molars; necroses are observed that involve part of the horizontal and the entire ascending branch with the articular head. The treatment of chronic osteomyelitis of the Jaws is reduced to maintaining free drainage of pus and to preventing displacement of fragments of the Jaws in spontaneous fractures, for which early preventive splinting is necessary. Removal of sequestra should be undertaken only when they are completely free, when a strong capsule has formed; sequestrectomy should be performed, if possible, from the oral cavity side. Prevention of odontogenic osteomyelitis consists in timely treatment of teeth. New formations of the jaws. Among new formations of the Jaws, first place is occupied by tumors genetically related to the pathology of the dental system, so-called odontogenic tumors; these include dental cysts (see.), adamantinomas (see.), odontomas (see.) and epulides (see.). Among these new formations, dental cysts are more common. Fibromas of the jaws (excluding epulides) are very rare. Kenterich (Kep-terich) collected 40 cases from the literature, of which 23 were on the lower jaw and 17 on the upper; fibromas of the jaw are divided into periosteal and central by location. In the area of wisdom teeth, sometimes symmetrical fibromas appear. Some authors associate the occurrence of these fibromas with the eruption of wisdom teeth; as these fibromas grow, they can lead to impaired chewing. Their therapy is surgical. - Osteomas of the jaws represent an undeveloped chapter of jaw pathology. Petrov believes that under the heading of osteomas of the Jaws, various processes are listed, and with the current state of our knowledge, it is not possible to determine their neoplastic, inflammatory or dystrophic nature. By location, 2 forms are distinguished - exostoses, sitting on the surface of the jaw on a limited basis and not reaching a large size, and osteomas, merging with the surrounding bone without a sharp border. Osteomas of the jaws grow slowly, sometimes under the influence of inflammation they spontaneously detach. The treatment of osteomas is surgical. Cancer of the jaws. According to Gurlt's statistics, covering 14,630 cases of malignant neoplasms, 532 fall on the jaws (3.4%). The upper jaw is affected by malignant neoplasms more often than the lower; cancers of the jaws are more common than sarcomas. Regarding the etiology of cancer of the jaws, many authors put forward a number of local specific factors, to which they attribute causal significance: long-term traumatization by carious teeth, irritation by a prosthesis, chronic sinusitis, papillary growths of the epithelial lining of dental cysts; some authors attach particular importance to embryonic dystopias of the epithelium in the thickness of the jaw and paradental embryonic remnants of Malassez. According to microscopic structure, most cancers of the jaws belong to squamous forms - keratinizing and non-keratinizing; on the upper jaw, sometimes cylindrical cell cancers originating from the epithelium of the maxillary cavity are found, although from it often develop squamous forms and adenocarcinomas, distinguished by rapid growth. Cancers of the upper jaw are in most cases primary, the starting point is the mucous membrane of the alveolar process, palate and maxillary cavity. When a neoplasm appears on the alveolar process, patients complain of loosening of the tooth, near which there is a small ulcer, and sometimes also of pain; after tooth extraction, the alveolus does not close, and from it quite quickly mushroom-like growths appear. In these cases, biopsy is a valuable diagnostic tool. Creeping, persistent ulcers of the mucous membrane of the palate with mushroom-like growths are characteristic of squamous cell cancer. Cancer of the maxillary cavity is difficult to diagnose, it can grow hidden for a long time without disturbing the patient. sometimes patients complain of dull pain in intact teeth, of bleeding or foul-smelling discharge from the corresponding nostril; in such cases, an X-ray is necessary; if the cavity is darkened or if there are destructive changes in its walls, trial trepanation of the cavity is necessary. The lower jaw is affected mainly secondarily, due to the spread of the process from the lower lip, cheek, tongue and lymphatic glands. Treatment. The main condition for a cure of cancer of the jaws is early surgical removal of the tumor. Any erosions, ulcers, cracks on the jaws, their processes and on the adjacent soft tissues, that do not respond to therapeutic interventions within 8-10 days, should be considered suspicious for cancer; one should refrain from repeatedly smearing such ulcers with silver nitrate. For prevention, it is necessary to eliminate traumatizing factors: sharp edges of teeth, poorly fitting prostheses, deeply seated roots, around which granulation growths often form. In already developed cancer of the jaws, radical surgical removal of the tumor within healthy tissues is the method of choice; radiation therapy should be considered an auxiliary method. Depending on the area involved by the tumor, partial or complete resection of the jaw is applied; partial resection can be performed from the oral cavity side. Complete resection of the upper jaw. A serious danger in complete resection of the upper jaw is pulmonary complications, caused by aspiration of blood and mucus during the operation. Preligation of the external carotid artery and the use of local anesthesia instead of inhalation anesthesia significantly reduce this danger. The most convenient incision for resection of the upper jaw is Weber's incision, which provides wide access to the jaw bone, spares the branches of the facial nerve, the mimic muscles and Stensen's duct. Having separated the flap outlined by this incision, the facial wall of the jaw is exposed and with a Gillie saw it is freed from the maxillary, frontal bone, the palatal processes are separated with a chisel, and after freeing the jaw from the pterygopalatine process, it is dislocated outward.

After stopping the bleeding and thoroughly cleansing the wound cavity, the lip and skin are joined with knot sutures. - Prosthetics. After resection of the upper jaw, the resulting cavity begins to scar, the scars pull in the cheek, turn the eyelid inside out, and communication between the oral cavity and the wound is very distressing for patients, therefore clinicians use prosthetics immediately after the operation (immediate prostheses); these prostheses, placed in the wound cavity immediately after surgery, significantly reduce facial disfigurement; the most justified method of immediate prosthetics and an improved prosthesis for this purpose was proposed by Entin - a pneumatic type prosthesis with an irrigation system {Fig. 6), however, it has not acquired wide practical significance. Resection of the lower jaw consists in removing a segment of the jaw over its length; it is applied when the tumor has captured the body of the jaw, but when the tumor spreads to the angle of the jaw and the ascending branch, it is necessary to disarticulate half of the jaw. Total removal of the lower jaw is a very rare operation. Preligation of the external carotid artery for disarticulation of half of the lower jaw is not mandatory; local anesthesia reduces the danger of aspiration. The incision is made from the middle of the chin, retreating 1-1/2 cm from the edge of the jaw, to the angle and continues along the posterior edge of the ascending branch to the level of the earlobe; tissues are dissected layer by layer to expose the lower edge of the jaw, at the same time cutting the jaw artery; after cutting the attachments of the m. masseteris and the medial pterygoid muscle, the soft tissues are separated from the bone with a periosteal elevator up to the coronoid process. Retreating 2 cm forward from the tumor, the jaw is sawn through with a Gillie saw, the mucous membrane is cut on both sides from the saw to the ascending branch, and the freed jaw is grasped above the angle with strong bone forceps, pulling it downward and backward (Fig. 7); the coronoid process is finally freed from the tendons of the muscles attached to it and is disarticulated from the joint by rotational movements. The mucous membrane is carefully sutured with catgut and the skin with silk or horsehair. After resection of the chin part of the jaw, the tongue must be taken on a ligature. After resection of part of the jaw or after disarticulation of half of it, displacement of the remaining fragments occurs, which leads to disruption of articulation, nutrition and facial disfigurement. These displacements must be prevented immediately after surgery with a pre-made prosthesis-splint by Sauer with an inclined plane (Fig. 8), if teeth remain on the fragments; for cases where there are no teeth on the remaining fragments, a number of splints have been proposed: Stoppani splint (Stoppa splint) (Fig. 9) made of aluminum, reproducing the configuration of the chin, Faltin splint (Fig. 10), Limberg splint, Parke splint and others. In disarticulation of half of the lower jaw, the most suitable method of prosthetics should be considered the use of a Weber splint with an inclined plane on the remaining half and with an extended wing-support for the soft tissues of the resected side (Fig. 11). Traumatic injuries to the jaws. Fractures of the jaw constitute about 70% of all fractures of the facial skeleton, the number of jaw wounds is especially great during wartime; statistics of the last war showed that about 60% of head wounds fall on the jaw, constituting about 10% of all wounds. The majority of facial and jaw injuries fall on the lower jaw, on which fractures of the body, alveolar process and ascending branch are distinguished. On the body of the lower jaw there are certain places where fracture lines most often pass: the area of the canine, the alveolus of which weakens the massive body of the lower jaw, the area of the premolars, lying in front of the oblique lines, the angle of the jaw, lying behind the oblique lines (the upper, massive part of the lower jaw is weakened here by the wisdom tooth socket), the neck of the articular process (the weakest place) and finally the middle line between the medial incisors. The most characteristic symptom in fractures of the lower jaw is disruption of the closure of the dental rows, caused by displacement of the fragments; the latter, due to the traction of the muscles, is expressed to varying degrees depending on the location of the fracture line. When the fracture line passes strictly along the middle line between the incisors, there is no displacement at all or it is expressed to a slight degree, since the traction of the opening and closing muscles of the mouth is evenly distributed on both fragments; with localization of the fracture between the median line and the anterior edge of the chewing muscle, the displacement will be the stronger the closer the fracture line passes to it; this is explained by the fact that in this fracture the musculature is unevenly distributed on both fragments: only the closing muscles (mm. masseter, pterygoid int., temporalis) act on the smaller fragment, while on the larger one, in addition, the opening muscles (both mm. geniohyoidei, digastricus and 3/4 m. mylohyoidei) act; therefore, the smaller fragment will be pulled upward, and the larger one will also be pulled downward and slightly inward. - In a double fracture with localization of the fracture lines on both sides of the chin, the main force of the opening muscles falls on the median fragment, which will be pulled downward; in this fracture there is a danger of asphyxiation due to the falling back of the tongue, especially when there are defects at the fracture sites. In fractures of the angle of the jaw, displacement will be pronounced when the fracture line passes in front of the angle; the articular process in fractures of the neck of the jaw is displaced backward, and the head forward. - Fractures of the alveolar process occur from direct impact on it, most often two or three alveoli are fractured; fracture of one alveola often occurs during tooth extraction, without giving any sign of itself, and therefore has no clinical significance. Treatment of fractures of the lower jaw pursues not only the restoration of the anatomical integrity of the bone, but also the preservation of the function of the chewing apparatus, which is achieved by restoring proper occlusion and articulation. For this purpose, as early as possible reposition and fixation of fragments is necessary, which in fresh cases does not present great difficulties; in cases where inflammation and edema have appeared, gradual traction has to be resorted to for reposition, and fixation undertaken only when proper occlusion has been achieved. The main modern method of treating jaw fractures is splinting with intraoral wire splints, which in the vast majority of cases can be completely managed with; only in the most complex and long-standing cases is it necessary to resort to more complex orthopedic devices. Bone suture should not be resorted to in jaw fractures. The material for splinting is aluminum round wire with a diameter of 1/4 mm, bronze-aluminum ligature wire, and for elastic traction, rubber rings cut from fresh drainage tubing. There are single-jaw splints, used for fixing easily set fragments (Fig. 12). In cases where immediate reposition of fragments is not feasible, intermaxillary traction is resorted to; for this purpose, splints with catching loops are used, placed on the upper jaw, which serves as a support, and on the fragment of the lower jaw to be repositioned; the splint and ligatures are incorrectly applied: the splint does not lie evenly around the tooth neck. (According to Limberg.) The jaw to be repositioned; the traction itself is performed with rubber loops. In fractures of the alveolar process, the fragment is repositioned and fixed with a single-jaw splint. Fractures of the upper jaw occur less frequently than fractures of the lower jaw. Despite the fact that the upper jaw is very firmly connected to the skull, certain typical fracture lines are noted in its injuries. Fort (L. Fort) described 3 main types of fractures of the upper jaw: the first type - when the fracture line passes horizontally above the alveolar process, crosses the maxillary sinuses, the nasal septum and the ends of the pterygoid processes; in a complete fracture, the entire fragment along with the palate sinks downward; in the second type of Fort fracture, the fracture line passes through the root of the nose, crosses the medial wall of the orbit and passes downward between the zygomatic bone and the zygomatic arch; posteriorly the fracture line passes through the nasal septum and at the base of the pterygoid processes; this fracture may be accompanied by cracks in the base of the skull; both jaws are mobile in this fracture. In the third type of Fort fracture, the fracture line passes through the root of the nose, transversely through the orbit, through the edge of the orbit and through the zygomatic arch; in this fracture, the jaw together with the zygomatic bones and the bony part of the nose is mobile, and the movement of the entire fragment is followed by the movement of the eyeballs. - Treatment of fractures of the upper jaw. Depending on the direction and force of the impact, the upper jaw either sinks down or is displaced inward toward the base of the skull. Forced reposition is contraindicated here; the vault of the skull serves as a support point for reposition by traction; some bandage - strap, plaster or fabric - is fixed to it, to which a splint fixed on the teeth of the upper jaw is pulled by rubber tubes.

Faltin proposed for this purpose a simpler wire splint, which in various modifications is used in all dental clinics for fractures of the upper Jaws (Fig. 13). In those cases where the Jaw is displaced inward and backward, a springy rod is attached to the head bandage, which serves to pull the Jaw forward (Fig. 14). Care of the oral cavity in patients with Jaw fractures must be the most meticulous throughout the entire treatment period. It is best to irrigate the oral cavity several times a day from an Esmarch's cup; for washing, a 2% solution of soda, a solution of potassium permanganate (1:5,000) is used. A refreshing solution is: T-rae Mug-rhae, Menthae pip., Spir. vini aa 20.0, Thymol 1.5, 30 drops per Esmarch's cup. Food for Jaw disease patients should be prepared in liquid and semi-liquid form so that patients, especially in the first days, can take it through a drinking tube, the tip of which is fitted with a rubber tube. Approximate menu (according to Entin): morning - a glass of milk and 25.0 sugar; breakfast - a glass of coffee with milk and 25.0 sugar, a raw egg; lunch - puree soup from potatoes or peas, cranberry kissel, a glass of milk, 50.0 butter, 100.0 oatmeal; afternoon snack - a glass of tea, 25.0 sugar, 50.0 oatmeal; dinner - a glass of milk, 50.0 oatmeal and a raw egg; daily 400.0 cranberries for fruit drink or 1/2 orange.