Chapter 7. Tooth Eruption Disturbances
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The eruption of deciduous and permanent teeth, as a rule, proceeds without complications; however,
due to various conditions including disturbance of phylogenesis and ontogenesis, the eruption of the
lower wisdom teeth, less often of the upper wisdom teeth, canines, and premolars of both jaws can
be accompanied by inflammation.
Endogenous and exogenous factors form the basis for anomalies of eruption and position of teeth.


Endogenous (genetic) anomalies in the size of the jaws and the position of teeth in them,
which arise under the influence of dysfunction of the endocrine system, lead to the change in the
ratio of the sizes of the jaws to the teeth. The lack of space in the alveolar part or the alveolar
process of the jaws causes retention of the teeth.
Exogenous factors including infant formula feeding and the intake of soft food by the child lead to
anomalies of the dentition.
The prevalence of caries and its complications, as well as early extraction of primary teeth, can
cause displacement and lack of space for the eruption of permanent teeth.
Early trauma to the maxilla or the mandible during the period of bone growth in children
adversely affects the development of the jaws and the teeth as it can contribute to the formation of
secondary deformities of the jaws, loss of primordia of permanent teeth, impaired occlusion,
deformation of the dentition and the development of inflammatory diseases.
Tooth eruption disturbances that are encountered in the practice of oral surgery include an anomaly
of the tooth position and an anomaly of its eruption, particularly, impaction, primary retention, and
primary failure of eruption.
o
According to the ICD-10 classification (Version: 2019), anomalies of eruption and position of the
teeth are included in the following class: Diseases of the digestive system (K00-K93).
K00-K14 Diseases of the oral cavity, salivary glands, and jaws.
K00 Disorders of tooth development and eruption. Excluded entities are: embedded and
impacted teeth (K01).
K00.0 Anodontia.

Hypodontia.

Oligodontia.
o
K00.1 Supernumerary teeth.

Distomolar.

Fourth molar.


Mesiodens.

Paramolar.

Supplementary teeth.
o
K00.7 Teething syndrome.

K01 Embedded and impacted teeth. Excluded entities are: embedded and impacted teeth with
abnormal position of such teeth or adjacent teeth (K07.3).
K01.0 Embedded teeth. An embedded tooth is a tooth that has failed to erupt without obstruction by
another tooth.
o
o
K01.1 Impacted teeth. An impacted tooth is a tooth that has failed to erupt because of obstruction by
another tooth.
o
K07.3 Anomalies of tooth position:

crowding;

diastema;

displacement;

rotation;

spacing, abnormal;

transposition
of tooth or teeth. Impacted or embedded teeth with abnormal position of such teeth or adjacent teeth.
Excluded entities are: embedded and impacted teeth without abnormal position (K01).
Inflammatory complications are most frequently associated with anomalies of the eruption of the
third molars of the lower jaw. Thus, the occurrence of periostitis, abscesses, and phlegmons of the
maxillofacial region sometimes accompanies the disturbance of tooth eruption and accounts for
11.6% of cases of their total amount.
The wisdom teeth of the lower jaw erupt mainly at the age of 18-25 years or later. The third molar
often has two roots and a well-defined crown, sometimes the number of the roots can be different,
the shape is curved.
The difficulty of the eruption of these teeth may be due to the following factors:

the absence of a precursor, namely, of the primary tooth, as a result of which the bone in this area is
compacted;

the presence of a powerful buttress in this area in the form of the external oblique line, which
includes a thick and dense cortical plate;

lack of space in the dental arch, as a result of which the tooth is located in the branch of the lower
jaw or abuts against it;

thickening of the mucous membrane containing the fibers of the buccal muscle and the superior
constrictor of the pharynx, which creates an additional dense barrier for the tooth eruption.
An important reason for the complicated eruption is the lack of space in the jaw, in particular in the
retromolar space, which leads to the delayed eruption of the wisdom tooth, sometimes for months
and years. This occurs due to the reduction of the lower jaw during phylogenesis when the distal
alveolar part is shortened. The third molar is the last to erupt, and there is not enough space in the
dentition. It was found that for the normal eruption of a wisdom tooth, the distance from the distal
surface of the second molar to the branch of the lower jaw should be 29 mm, in other cases
conditions for pathology arise (Fig. 7.1).
Fig. 7.1. Variants of the inclination of the tooth axis in relation to the distal alveolar part of the
lower jaw and its branches
Complicated eruption of the lower wisdom tooth with sufficient space between the second molar and
the ramus of the mandible may be associated with the thick keratinized mucous membrane covering
the retromolar fossa and its relationship with the erupting tooth.
The eruption of the wisdom teeth is also affected by:

inflammation of the root of the adjacent tooth;

early loss of deciduous teeth;

convergence of the crowns of two permanent teeth;

the curvature of the root of the wisdom tooth;

the anomaly of the anatomical structure of the tooth;

hypercementosis;

the cementoma of the root.
The growth period of the lower jaw, including its longitudinal changes, is of great importance since
it determines whether a wisdom tooth will erupt or not. Statistically, 9.5 to 39% of th lower wisdom
teeth fail to erupt in the oral cavity. Incorrect location of the germ of the wisdom tooth in the jaw,
pathology of growth and development of the jaw leads to its mesioangular impaction (the tilt to the
direction of the second molar), less often distal-angular, vertical, horizontal, inverted impaction. The
anomaly in the growth and development of the jaw and the germ of the wisdom tooth, which is
associated with the zone of appositional bone growth, also becomes the cause of the complicated
eruption.
After the emergence of one or both medial cuspids, the position of the tooth is further unchanged,
its crown is located below the level of the crowns of the first and second lower molars, and part of
its chewing surface is covered with the operculum, under which accumulation of the abundant
microflora of the oral cavity and food particles is observed. This factor, as well as the frequent
trauma to the mucous membrane, overlying the semi-impacted tooth, when chewing, are considered
the causes of inflammation in the soft tissues surrounding the tooth, which is defined
as pericoronitis, and inflammation of the periosteum of the retromolar fossa, that is entitled
retromolar subperiosteal abscess.
The disturbance of eruption of the third molar may lead to malocclusion that is followed by
disequilibrium of soft tissues of the face. The sequelae of the complicated eruption of the wisdom
tooth can be the reason for the development of periostitis, osteomyelitis, abscess, phlegmon. Rarely,
pericoronitis causes ulcerative stomatitis, periodontal cysts and leads to other complications.
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7.1. Pericoronitis
The first and the most frequent clinical manifestation of the complicated tooth eruption
is pericoronitis, the inflammation of the soft tissues surrounding the crown of the tooth in case of its
partial or complicated eruption, which often occurs in the area of the lower third molar. The term
“pericoronitis” comes from the Latin pericoronitis (peri ― around, corona ― the crown of the
tooth, it is ― the ending denoting inflammation). It is also known as operculitis, which means
inflammation of the soft tissue, surrounding the crown of an impacted or semi-impacted tooth.
The soft tissues, that are present around the crown of the tooth during the process of eruption and
partially cover it, are known as the operculum, or pericoronal hood.
Pericoronitis most often develops due to the disturbance of eruption of the lower third molars,
frequently at a young age (18-25 years), which correlates with the expressed general reactivity of the
organism. There is higher chance of pericoronitis in case the mandibular third molars are partially
covered with soft tissue, compared to total coverage with mucous membrane or full eruption.
If the integrity of the mucous membrane covering the tooth in the retromolar region is disrupted,
food debris, epithelial cells, and microflora of the oral cavity enter the pericoronary space (between
the crown and the mucous membrane). In this space, favorable conditions arise for the development
of the obligate and the facultative anaerobic microorganisms, since it is impossible to maintain
adequate hygiene under the pericoronal hood.
The food residues, which are accumulated in that area, support the vital activity of the normal
(resident) microflora of the oral cavity, which is revealed in this area in an amount that is several
orders higher than its content in other sites. In addition, a decrease in the level of the local defense
mechanisms of the body and an increase in sensitization in this anatomical site contribute to the
occurrence of inflammation.
Pericoronitis is characherized by polymicrobial nature, the microbiota that colonizes and settles on
the infected pericoronary tissue is mainly comprised of obligatory anaerobic microorganisms (80%),
microaerophilic organisms, and facultative anaerobes. There are not only abundant obligate
facultative anaerobic microflora present, such as the Streptococcus milleri group - Stomatococcus
mucilaginous and Rothia dentocariosa, but also anaerobic bacteria, in particular, Actinomyces and
Prevotella species.
The situation is aggravated due to trauma of the mucous membrane by the crown of the antagonist
tooth of the upper jaw. Constant traumatizing of the mucous membrane covering the retromolar
fossa, which occurs during the chewing process, leads to its cicatrization and sclerosing. If the
mucous membrane overlying the partially erupted tooth, is changed by scarring, it leads to the
complicated tooth eruption, stopping the movement of the tooth. In this case, a periodontal pocket
can be formed under the operculum and over the partially or completely erupted tooth crown.
Frequent trauma to the pericoronal hood and relapses of inflammation causes an inflammatory
process, which proceeds as chronic marginal periodontitis and chronic gingivitis. As a result, the
growth of granulation tissue in the area of the tooth neck and bone resorption in this area occurs,
which leads to the formation of a pathological bone-gingival pocket.
It was found that vertical and distoangular impactions of wisdom teeth are more frequently
associated with pericoronitis when compared to other angulations. Some third molars with
distoangular impaction, after penetrating bone, encounter an additional obstacle to the eruptions in
the form of a thick retromolar pad that is present instead of the morphological gingival tissue which
is normally located in this area.
Systemic factors play important role in the trigger mechanism of pericoronitis, which can lead to
disorders in the patient's immune system: influenza, upper respiratory tract infections, stress,
changes in metabolic processes, endocrine diseases, vitamin deficiencies, etc.
.1.1. Acute Pericoronitis
Acute pericoronitis is an inflammatory process of the tissues of the gingivae and marginal
periodontium in the region of the third molar, that is connected with its complicated
eruption.
The disease has the following forms:

serous (catarrhal);

suppurative (purulent);

ulcerative.
By the severity of the course, acute suppurative pericoronitis is divided into stages:

mild;

moderate;

severe.
Acute Serous Pericoronitis
Acute serous pericoronitis also known as catarrhal pericoronitis occurs at the onset of the
disease. Patients complain about mild or moderate aching pain, that is localized in the
distal parts of the lower jaw of the corresponding side and enhance when chewing.
Sometimes the edematous mucous membrane of the gingivae in the area of inflammation
comes into contact with the crown of the antagonist tooth, which contributes to a sharp
increase in pain when closing the mouth.
The general state is satisfactory, the body temperature is normal. Collateral edema in the
maxillofacial region is absent. On external examination, in some cases, an enlarged and
painful lymph node is found in the submandibular or retromandibular region of the
corresponding side. The opening of the mouth is without limitations, but often painful.
Inflammatory contracture of the I-II degree is observed rarely.
During the examination of the oral cavity, it is noted that the mucous membrane totally or
partially (from the distal aspect) covers the crown of the erupting third molar, while the
emergence of one or two medial cuspids of the tooth in the oral cavity is present. The
mucous membrane is hyperemic, edematous, painful on palpation. The area of hyperemia
and edema is usually not spread beyond the retromolar triangle and the lower parts of the
pterygomandibular fold. When probing the pocket, no discharge is obtained. Characteristic
impressed areas due to the contact with the antagonist tooth can be observed on the
surface of the mucous membrane covering the crown of the tooth. Often there are erosions
and ulcers of the mucous membrane detected in this area, that are caused by chronic
trauma (fig. 7.2, 7.3). If the inflammatory process is not stopped spontaneously or under
the influence of therapeutic measures, it turns to the purulent stage.
Fig. 7.2. Orthopantomogram. Position anomaly and delayed eruption of the tooth 3.8
Fig. 7.3. Ulcer of the mucous membrane in the area of tooth eruption
Acute Suppurative Pericoronitis
The disease is characterized by an increase in symptoms due to the spread and
intensification of the inflammatory reaction. In this case, patients have complaints of
constant moderate or intensive pain in the area of the wisdom tooth, which is sharply
increased when chewing, closing the teeth, during a conversation. Pain occurs when
swallowing and opening the mouth. The symptom is more pronounced in purulent form
than in the serous, becoming the most significant feature due to its local intensity and
tendency to radiate towards adjacent anatomic structures, thus, it often leads to trismus,
dysphagia, odynophagia, otalgia on the ipsilateral side of the affected mandible.
The general condition is disturbed, symptoms of intoxication are poorly expressed, the
body temperature is increased to 37.0-37.5 °C. On external examination, sometimes the
doctor reveals mild edema in the posterior department of the submandibular region and the
inferior departments of the parotid-masticatory region. Several lymph nodes are enlarged
and sensitive in the submandibular or retromandibular region. Mouth opening is painful due
to the spread of the inflammatory reaction to the area of the masticatory muscles (mainly to
the lower sections of the medial pterygoid muscle and the posterior sections of the
mylohyoid muscle).
The mucous membrane is sharply hyperemic and edematous in the retromolar region.
Palpation of this area causes sharp pain; when probing, pus is obtained from under the
operculum. Edema and hyperemia are often spread upwards along the pterygomandibular
fold to the palatine arch, however, palpation in these areas is painless, which makes it
possible to exclude the presence of an inflammatory process in the pterygomandibular or
parapharyngeal spaces. If traces of contact with the antagonist tooth in the form of erosions
and ulcers are distinctly visible on the mucous membrane, ulcerative pericoronitis is
diagnosed.
Ulcerative Pericoronitis
The disease is characterized by a more severe course, deterioration in general state, an
increase in body temperature above 38 °C, and putrid breath. Palpation of inflamed tissues
is painful. When probing under the operculum, moving the probe posterior to the second
molar reveals the crown of the wisdom tooth.
In case of the correct position of the tooth and sufficient space, the inflammatory
phenomena disappear after the performed treatment. On the contrary, if there is not
enough space for the third molar in the retromolar fossa, the abundant microflora that is
concentrated under the operculum periodically causes inflammatory processes with the
development of chronic pericoronitis.
With timely treatment of the disease, the prognosis is favorable. In the case of the spread
of a purulent infection, complications are possible, ranging from ulcerative gingivitis to
phlegmons of the maxillofacial region.
7.1.2. Chronic Pericoronitis
The transition of the inflammatory process to the chronic stage is possible after the first acute
inflammation, but it happens more often after repeated exacerbations. The inflammatory process is
similar to chronic marginal granulating periodontitis. In case when the proliferation of granulation
tissue is constrained, limited granulomatous marginal periodontitis occurs in this area.
The clinical picture varies. Chronic forms are often present in a subclinical form, or with few
symptoms, with complaints of mild yet constant pain. In some cases, chronic pericoronitis occurs
without a clinically pronounced acute stage. Patients present with rare complaints of bad breath and
discomfort in the area of the operculum. When chewing food, insignificant soreness occurs in the
area of inflammation, but the general condition of the patient is not disturbed.
On external examination, no signs of the disease are determined. Sometimes, there is an enlarged,
mobile, mildly painful, or painless lymph node palpated in the submandibular or retromandibular
space. In the oral cavity, the mucous membrane, which partially or completely covers the crown of
an erupting tooth, is hyperemic, edematous, and serous or purulent exudate is obtained from under it.
Palpation in this area is mildly painful.
An X-ray examination can reveal a zone of rarefaction of bone tissue posterior to the crown of the
tooth, that spreads along the root downward and backward, often acquiring a semi-oval shape of a
deep and wide bone pocket (Fig. 7.4).
Fig. 7.4. Orthopantomogram. Bone loss in the area of the crown of the tooth 4.8 with distinct oval
contours
As investigated by Kay L.W. (1966), during its development, the tooth germ is enclosed by a rim of
the follicle and this, in turn, is surrounded by an outer margin of the condensed bone. A semilunar
radiolucent gutter occupied by follicular tissue persists on the distal aspect of the third molar and,
typically, this is bounded by an intact, white limiting line. Frequent repeated exacerbations of
pericoronal disease or an unremitting chronic pericoronitis will cause a discontinuity in the cortical
rim of the follicular space, and partial loss is followed eventually by the disappearance of the
remainder of the definitive margin. This leads to irregular destruction of the peripheral cancellous
bone later, and the thin crescentic radiolucent band enlarges to such an extent that the defect
becomes crateriform in shape and presents itself as a distal radiolucency.
An exacerbation of a chronic inflammatory process is accompanied by a clinical picture
characteristic of acute purulent pericoronitis.
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7.1.3. Diagnostics
Establishing the diagnosis of pericoronitis usually does not meet difficulties. The disease is
diagnosed based on a characteristic clinical picture, particularly, the presence of an inflammatory
process in the area of the mucous membrane that completely or partially covers the lower third
molar (its crown may be intact), and an X-ray data, according to which destructive changes in bone
tissue are detected distal to the tooth.
Differential diagnosis of pericoronitis is carried out with pulpitis and periodontitis,
with neuralgia of the third branch of the trigeminal nerve due to the similarity of pain.
Sometimes a carious process occurs at the root of an incompletely erupted tooth, which is often not
visually determined since the tooth is covered with a mucous membrane. It can be determined by
probing and/or by radiological examination. The onset and rapid development of the carious process
are facilitated by favorable biological conditions formed under the operculum, which can eventually
lead to pulpitis. In these cases, an association of pericoronitis and pulpitis or pericoronitis and
periodontitis is possible. The presence of pain after the treatment of pericoronitis, as well as probing
of the carious cavity, tooth percussion, and electric pulp test data, assist in stating the diagnosis.
7.1.4. Treatment
Management of acute pericoronitis is aimed at evacuating pus from under the operculum,
creating conditions for the outflow of exudate by dissecting the area of the mucous
membrane hanging over the crown of the tooth (Fig. 7.5), as well as providing antiinflammatory treatment.
Fig. 7.5. Illustration of mucosal dissection over the crown of the erupting lower molar
Before starting the treatment procedures for pericoronitis, radiological examination, namely,
OPG is necessary to determine the position of the third molar in the jaw and its state. Using
the data obtained from the radiograph, it is determined whether the third molar is to be
removed or if it should be preserved.
The type of the surgical procedure mainly depends on the results of the X-ray examination
and may be represented by excision or dissection of the operculum.

Embedded and impacted teeth are subject to extraction in case there is not enough space
for their eruption in the alveolar part of the lower jaw.

In addition, it is advisable to extract teeth in any of their locations, when they are
accompanied by a focus of chronic infection: chronic marginal or apical periodontitis,
associated with chronic pericoronitis.
If the tooth is to be removed, the procedure is performed not earlier than 2-3 weeks after
the complete elimination of inflammation. This is optimal since performing traumatic
surgical procedures in the bone tissue (surgical tooth extraction using a physiological
dispenser) in case of acute inflammation, promotes the spread of infection to the adjacent
tissues. The disturbance of the balance of local non-specific and immune reactions may
also occur, which contributes to the development of the osteomyelitis process. Tooth
extraction is indicated in the case of chronic pericoronitis in the remission stage.
To stop the inflammatory process in acute pericoronitis, the space under the operculum is
treated with antiseptic solutions [0.05% chlorhexidine solution (Chlorhexidine digluconate♠),
Miramistin♠, Octenisept♠], a longitudinal incision vertically crossing the operculum is
performed to provide drainage of the exudate. For the outflow of serous or purulent
exudate, antibacterial, anti-inflammatory therapy is prescribed. When the inflammatory
process ends, the doctor should choose the optimal tactics of the further treatment that is
either removing or preserving the tooth.
Apart from tooth extraction, surgical treatment of chronic pericoronitis may be represented
by operculectomy, namely, the excision of the mucous membrane and complete exposure
of the crown of the wisdom tooth, curettage of granulations. It is performed in case the
tooth stays in the correct position. Excision is performed using a scalpel, microsurgical
sharp-pointed scissors, laser radiation, or radiofrequency scaler. The operation is
performed under infiltration anesthesia: a part of the mucous membrane is excised with a
semi-oval or rectangular incision, departing from the intended projection of the crown
boundaries by 1-2 mm (Fig. 7.6, 7.7). The diameter of the mucous membrane area that is
subject to excision should not be less than the diameter of the crown of the tooth (Fig. 7.8).
After excision between the mucous membrane (wound surface) and the lateral surface of
the crown, a gauze stripe with triiodomethane (Iodoform♠), alternatively, a portion of
Alveogyl (Septodont) is immersed along the entire perimeter of the wound, with retraction
of the edge of the mucous membrane from the crown of the tooth. In the postoperative
period, the patient is prescribed non-narcotic analgesics in case of pain, as well as oral
baths with antiseptic solutions or herbal decoctions 4-6 times a day until the inflammation is
relieved. It is better to alternate the baths.
Fig. 7.6. Operculum over the distal crown of the tooth 4.8
Fig. 7.7. Scheme of excision of the mucous membrane above the crown of the erupting
lower molar
As a rule, there are no complications associated directly with the operation, except for the
possibility of minor capillary bleeding from the wound surface that is due to inflammatory
vascular hyperemia, as well as to vasodilation after the end of the action of vasoconstrictor.
Bleeding is stopped by pressing a gauze that is moistened with a hemostatic medication
[hydrogen peroxide (hydrogen peroxide♠), aminocaproic acid + ferric chloride + sodium
chloride (Caproferr♠), aminocaproic acid solution, etc.] to the bleeding site. Rarely, as a
result of further progression and spread of the inflammatory process, pericoronitis can be
complicated by the development of periostitis, abscess of the mandibular-lingual groove,
abscesses, and phlegmons of other localizations.
Fig. 7.8. Excision of the mucous membrane over the crown of the lower molar with a laser
device
7.2. Subperiosteal Abscess of the Retromolar Trigone
Subperiosteal abscess of the retromolar trigone, also known as retromolar subperiosteal abscess, or
retromolar periostitis, arising as the complication of acute purulent pericoronitis, occurs due to the
disturbance of the exudate outflow in case of pericoronitis and the spread of the purulent infection
from under the operculum to the periosteum and the cellular tissue of the retromolar trigone, where
an abscess may be formed. The retromolar trigone (fossa, space) is a triangular region that is located
between the lower third molar and the ramus of the mandible and is covered with gingival mucous
membrane. The anatomical and topographic features of the retromolar fossa are of great importance
in the development of the purulent process. The retromolar fossa is located in the anterior part of the
mesial surface of the branch of the lower jaw. The retromolar triangle is present anterior to the fossa.
Fibers of the buccal and temporal muscle, of the upper constrictor of the pharynx, pass through these
structures, and between the fibers, there are layers of loose fat cellular tissue, which determines the
spread of the purulent process in case of disturbances of the tooth eruption.
The disease is characterized by clinical symptoms that are similar to purulent pericoronitis, but more
pronounced. Patients complain about pain in the area of the erupting tooth, restriction of mouth
opening due to spasm of the masticatory muscles (II-III degree), sharp pain when swallowing.
Disturbed common state, characterized by weakness, malaise, an increase in body temperature to 3838.5 °C. Chewing food is impossible, sleep and appetite are disrupted.
The patient is pale, pronounced tissue edema is detected in the posterior department of the
submandibular region and the lower part of the buccal region. Submandibular lymph nodes are
increased, their palpation is painful. The intraoral examination is possible only after performing a
preliminary nerve block of the motor branches of the trigeminal nerve (according to the BercherDubov technique). Inflammatory changes of the mucous membrane around the erupting wisdom
tooth are more significant than those that arise in case of acute purulent pericoronitis and spread to
adjacent areas of the oral mucosa. A semi-impacted tooth is observed, covered with an edematous
and hyperemic mucous membrane, and a subperiosteal abscess is observed in the retromolar fossa,
representing an elevation of soft tissues, extending to the external surface of the lower jaw in the site
of the beginning of the external oblique line. There is the pronounced hyperemia of the surrounding
soft tissues in the area of the pterygomandibular fold, palatine arch, soft palate, mucous membrane
of the posterior department of the vestibulum of the oral cavity. Palpation of the operculum and
tissues surrounding it is sharply painful.
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7.2.1. Diagnostics
The retromolar subperiosteal abscess is diagnosed based on the characteristic clinical picture and
radiological data. Complete blood count reveals insignificant changes in parameters characterizing
inflammation: an increase in ESR up to 25-30 mm/h, leukocytosis; but the degree of the shift in
these indicators depends on the type of inflammatory reaction.
The development of an inflammatory infiltrate in the retromolar region and a pronounced restriction
of opening the mouth accompany the retromolar subperiosteal abscess, in contrast to acute
pericoronitis.
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7.2.2. Treatment
Treatment of retromolar subperiosteal abscess is carried out in an outpatient facility. The complex of
treatment procedures includes incision and drainage of the inflammatory infiltrate and abscess
cavity. In case the lower third molar, which is located in the area of the inflammatory focus, must be
removed, the tooth extraction is postponed and performed not earlier than 2-3 weeks later after the
complete elimination of inflammatory phenomena.
Incision of the subperiosteal abscess in the retromolar region is performed under local anesthesia
(Fig. 7.9). The manipulation is accomplished beginning from the lower third of the
pterygomandibular fold, going downward, dissecting the soft tissues and the periosteum in the
retromolar region, as well as the pericoronal hood. Then the scalpel blade is turned at an angle and
the incision is continued vestibular downward to the transitional fold (Fig. 7.10). Often, the
inflammatory infiltrate extends in vestibular direction vestibular towards lower molars. In these
cases, it is necessary to continue the incision along the transitional fold.
Fig. 7.9. Subperiosteal abscess in the right retromolar space
Fig. 7.10. Scheme of incision of the retromolar subperiosteal abscess
During the entire incision, the scalpel reaches the bone. After this, the periosteum is delaminated
from the bone along the entire length of the incision with a raspatory or a sickle trowel in both
directions to 1.5-1 cm, targeting to open all cavities filled with pus. The wound is drained with two
strips of the surgical glove. One strip is immersed posteriorly from the retromolar area in the
direction of the pterygomandibular space, and the other from the vestibular side downwards and
backward.
The draining strips of the sterile glove are changed daily during the treatment of the wound with
antiseptic solutions until the suppuration stops (usually 3-4 days), then they are removed, the wound
is kept being rinsed with antiseptic solutions. The patient is prescribed antibiotics, antihistamines,
antioxidants, adaptogens, and multivitamins perorally. To relieve pain, especially in the first hours
after surgery, non-steroid anti-inflammatory drugs are prescribed. Good anti-inflammatory effect is
given by PTT, in particular, UHF, magnetotherapy, microwave therapy, fluctuorisation, laser
irradiation is used for this purpose.
Local treatment includes the application of oral baths with antiseptic solutions 6-8 times a day.
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7.2.3. Complications
During the incision, bleeding may occur from small branches of the buccal artery. To stop the
hemorrhage, it is necessary to thoroughly dry the wound with the sterile gauze pads, identify a
bleeding vessel, and apply a hemostat or ligate it (putting sutures).
In case of the further development of the inflammatory process, abscesses of the mandibular-lingual
groove, abscesses, and phlegmons of the parapharyngeal and pterygomandibular fascial spaces,
parotid-masticatory, and submandibular areas may occur. Less often, the bone tissue is involved in
the purulent process, and odontogenic osteomyelitis of the jaw develops.
In the long-term postoperative period, patients may suffer from inflammatory contracture of the
lower jaw. For its treatment and prevention of its transition to cicatricial contracture, PTT, muscular
exercises, and mechanotherapy are prescribed.
Patients with retromolar subperiosteal abscess are disabled for 3-5 days. Patients whose work is
associated with extreme conditions, harmful production, physical stress, are exempted from work for
2-3 weeks.
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7.3.1. Delayed Tooth Eruption
Delayed tooth eruption (DTE) is the emergence of a tooth into the oral cavity at a time that delays
significantly from norms. In this case, a completely developed tooth can be buried in the jaw
asymptomatic for a long time, which is called a delayed tooth eruption (retention of the tooth).
Sometimes it is associated with diseases and injuries of the dentoalveolar system. Cicatrisation
including that due to surgical trauma, may be the predisposing factor for DTE. Gingival hyperplasia
resulting from various causes (hormonal or hereditary causes, vitamin C deficiency, drugs such as
phenytoin) might cause an abundance of dense connective tissue or acellular collagen that can
impede tooth eruption. Odontomas and other tumors (in both the deciduous and permanent
dentitions) have also been occasionally reported to be responsible for DTE. Teeth which eruption is
delayed are more common in the permanent dentition in the mandible and maxilla (Fig. 7.11, 7.12).
Fig. 7.11. Multispiral computed tomogram. The impaired eruption of the tooth 2.3
Fig. 7.12. Orthopantomogram. The abnormal position of the teeth 2.3, 1.8, 2.8, 3.8, 4.8
Clinically, pseudoanodontia occurs, with the absence of the tooth in the oral cavity, but its presence
in the bone. The delayed tooth eruption can be identified using conventional dental radiographs. In
the place of an absent permanent tooth in an adult’s dentition, a deciduous tooth grows or the gap is
partially or fully filled with adjacent teeth. The embedded teeth can displace adjacent teeth,
disrupting their normal position. In some cases, the clinical symptom of the tooth embedding may be
represented by a local bony prominence in the area of the alveolar process or alveolar part,
especially in the absence of a tooth in the dental arch.
Under such prominence, it is sometimes possible to palpate the contours of a tooth or part of it.
Embedded teeth may compress the alveolar nerves and their branches. In this case, severe pain,
irradiating to the temporal, the frontal region, and the ear, depending on the localization of the tooth,
and Vincent’s symptom are present. Often, an embedded tooth becomes a source of the
inflammatory process.
In case of incomplete eruption of the canines and upper or lower wisdom teeth through the bone
tissue or mucous membrane, when a part of the tooth crown appears, an inflammatory process may
occur around it. This happens since there is a permanent injury to the mucous membrane adjacent to
the erupting part of the tooth crown. Sometimes, a partially erupted tooth is detected in case of an
inflammatory process. When examining the oral cavity, a thickening of the alveolar process or its
part, covered with a hyperemic edematous mucous membrane, is determined. Partially erupted teeth
are often asymptomatic and are usually incidental findings.
In the upper jaw, the inflammatory process during the eruption of canines or the third molar is
characterized by pain due to the pressure on the adjacent teeth, unilateral edema of the mucous
membrane covering the alveolar process, and acute periodontitis. The spread of an inflammatory
exudate into the adjacent peri-maxillary tissues can lead to subperiosteal abscess of the jaw and
acute maxillary sinusitis. Acute osteomyelitis occurs rarely (as a rule, with recurrent inflammation).
Diagnosis
Diagnosis of DTE is based on the analysis of the clinical signs and the results of X-ray examination.
The radiograph allows the doctor to determine:

a tooth or part of it located deeply in the alveolar process, in the body of the mandible or the maxilla;

partially erupted tooth ― part of its crown is covered with the bone;

unerupted tooth ― completely embedded in the bone.
Treatment
The management of DTE depends on the clinical signs and includes tooth extraction or preservation.
In the presence of an inflammatory process, the treatment is fulfilled according to the guidelines of
treating an inflammatory disease of the oral cavity and maxillofacial region. After the elimination of
signs of inflammation, the doctor should select the treatment option. In case of incomplete tooth
eruption in the proper position and the presence of space in the dentition, it is left untouched, and an
operculectomy may be performed, completely exposing the crown of the tooth. Tooth extraction is
indicated in the following cases:

tooth impaction;

the subsequent anomaly of the tooth position:
o
the horizontal position of the tooth, or inclined under the angle less than 90 degrees to the occlusal
plane;
o
tooth rotation by 180°;
o
the impossibility of normalizing the tooth position by orthodontic methods;

deficiency or absence of space in the arch for tooth eruption;

abnormally shaped tooth.
7.3.2. Anomalies of Tooth Position
The degree of the abnormal tooth position can range from an insignificant deviation of the
longitudinal axis of the tooth compared to the normal position to the presence of the tooth in the
upper half of the mandibular ramus, etc. Anomalies of tooth position are characterized by the
presence of displaced erupted, semi-impacted, impacted or embedded teeth occupy an alternative
position in the dental arch or outside it. The lower third molar is more commonly displaced than the
upper third molar, canine (Fig. 7.13, 7.14), premolars, and incisors.
Fig. 7.13. The abnormal position of the tooth 1.3
Fig. 7.14. The abnormal position of the tooth 2.3
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Tooth displacement mainly occurs as a result of the disturbance of the eruption sequence and timing.
The tooth can have the anomaly of position towards the vestibulum or, on the contrary, the oral
cavity, medially to or distally from the midline, reversed around its axis, located below or above
adjacent teeth. Often a tooth can be displaced in two or three directions at once in relation to the
dental arch. Sometimes there is an abnormal position of several teeth (two, three teeth, or more).
A tooth that erupted in an abnormal position can cause a change in the position of other teeth, which
leads to malocclusion and, as a result, functional and aesthetic problems. When the tooth is
displaced towards the vestibulum or to the oral cavity, the mucosa of the lip, cheek, tongue is injured
with the formation of erosions and decubital ulcers.
Diagnosis
The diagnostic process is not difficult. Clinically, the doctor identifies a tooth protruding from the
dental arch or located incorrectly in relationship with the adjacent teeth, acquiring additional
information from the radiological study.
Treatment
The management of abnormal tooth position is usually carried out during the period of mixed
dentition when all types of anomalies of tooth position can be eliminated easier by various
orthodontic methods. As a rule, treatment is provided before the age of 14-15 years. It is possible to
use these methods at an older age, but in that case, the duration of orthodontic treatment increased. If
orthodontic treatment fails or is not indicated, the tooth is extracted. According to indications for
orthodontic treatment, it is possible to extract both upper and lower wisdom teeth. In case of oral
mucosal injury caused by an abnormally located tooth, grinding of the cuspids or the incisal edge of
the tooth is performed.
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7.4. Surgical Extraction of Impacted, Embedded Teeth and Anomalies of Their Position

Before extraction of an impacted, embedded tooth and/or in case of its abnormal
position, radiographic examination (X-ray) is obligatory to verify the location of the tooth in
relation to adjacent teeth and significant anatomical structures (the nasal cavity, the maxillary sinus,
the mandibular canal, the mental foramen, etc.) for planning the surgical access and choosing the
tooth extraction techniques.
Then, the surgical intervention is accomplished, which consists of anesthesia, incision, the
elevation of a mucoperiosteal flap, trepanation of the bone (removal of the bone layer that covers the
tooth), luxation and extraction of the tooth, or sectioning (separation) of the tooth crown and
removal the tooth in parts, adjusting the flap and suturing the wound. Such operations present
significant difficulties, lasting 40 minutes or more, in all cases, it is necessary to release the tooth
from the bone tissue in which it is located. The degree of complexity of the intervention depends on
(Fig. 7.15):
the location of the tooth in the jaw;

the depth of the embedded or impacted tooth;

the inclination of the tooth axis in relation to the distal part of the alveolar part of the mandible and
its branches;

configuration and number of roots;

the presence of ankylosis;

the amount of bone tissue covering the tooth;

topographic features of the jaw and adjacent anatomical structures.
Fig. 7.15. The impaired eruption of the lower wisdom tooth: types of root configuration, medial
inclination. The red dashed line indicates the cutting line when sectioning the crown
7.4.1. Surgical Technique

Surgical extraction of an impacted, embedded tooth and/or in case of its abnormal position
is carried out under local anesthesia (conduction and infiltration). For removal of an
unerupted or incompletely erupted tooth, a semi-oval, trapezoidal or angular incision of the
mucous membrane is performed to expose the bone in the area of trepanation, depending
on the tooth location.

When extracting impacted or embedded canines and premolars from the vestibular side, a
semi-oval or trapezoidal incision are convenient for the forthcoming trepanation of the
bone. The formed flap should overlap the trepanation foramen.

An angled incision is usually performed in the area of the lower wisdom teeth.

In the area of the upper first molar, an incision in the mucous membrane and periosteum is
fulfilled at an angle of 90 degrees, directed upward to the fornix of the vestibulum.
When the tooth is removed from the side of the palate, an incision is made through the
mucous membrane and periosteum of the hard palate to form a trapezoidal, semi-oval, or
angular flap. Then the flap is raised, and the bone tissue that covers the tooth is removed
using a physiodispenser or a surgical ultrasonic device with a special tip that allows
working with the bone tissue. The tooth is removed with elevators or forceps if necessary. If
the tooth is stable in the bone or it is impossible to remove the mobile tooth through the
trepanation hole (this depends on the shape and location of the tooth, as well as the
topographic features of the area where the surgery is performed), it should be separated
into several parts with a bur (cutter) (Fig. 7.16, 7.17).
Fig. 7.16. Fragmentation of the tooth crown with a bur: a - the position of the lower wisdom
tooth; b - sectioning and extraction of the crown; c - tooth root removal
Fig. 7.17. Separating of the tooth into fragments with a bur: a - the position of the lower
wisdom tooth; b - sectioning of the tooth crown, extraction of the crown; c - tooth root
removal
After that, the tooth is removed from the bone part by part. After extracting a tooth,
granulations are removed carefully with a curettage spoon. When teeth are extracted in the
upper jaw, curettage should be carried out gently so as not to perforate the nasal cavity
and the maxillary sinus mucosa.
Then, the doctor should perform antiseptic treatment of the bone wound, smoothen the
sharp bone edges, adjust and place the mucoperiosteal flap and fix it with interrupted
sutures or cover it with iodoform gauze or special dressing, if it is impossible to properly
approximate the wound edges. A bone defect after the tooth extraction can also be filled
with biomaterial, autograft, allograft, or alloplastic material.
If the surgical intervention is performed for the reason of orthodontic treatment, the oral
surgeon must know the orthodontist’s plan for moving teeth and, depending on this,
perform a bone graft procedure. Otherwise, bone remodeling and dense bone structure
limit orthodontic treatment. In the postoperative period, extraoral application of icepack in
the projection of the surgical site is prescribed for 3 days, broad-spectrum antibiotics for 5-6
days, anti-inflammatory and desensitizing therapy. Locally, rinsing, mouth baths with 0.02%
or 0.05% chlorhexidine solution (Chlorhexidine digluconate♠), PTT are prescribed.
Extraction of impacted, embedded teeth or those with impaired position is a rather
demanding operation, after which inflammatory complications are possible due to the
spread of infection to nearby areas and spaces of the face and neck, the development of
abscesses and phlegmons. The occurrence of alveolitis, limited osteomyelitis of the jaw in
the area of wound healing is also possible. This may be due to both pre-existing
inflammation in the area of the wisdom tooth and bone necrosis when drilling with a bur
without water cooling. Thus, a physiodispenser with cooling and a low-speed handpiece is
used to prevent bone overheating during osteotomy.