Category Archives: Principles of Management and Prevention of Odontogenic Infections

Pricniple IV:Treat Infection Surgicaily

Pricniple IV:Treat Infection Surgicaily

FIG. 15·8 A, Periapical infection of lower premolar extends through buccal plate and creates sizable , vestibular abscess. B, Abscess is incised with no. 11 blade. C, Beaks of hemostat are inserted through Incision and opened so that beaks spread to break up any loculations of pus that may exist in abscessed tissue .. 0, Small drain is inserted to depths of abscess cavity with hemostat. E, Drain is sutured into place wlth·single black silk suture.

FIG. 15·8 A, Periapical infection of lower premolar extends through buccal plate and creates sizable
, vestibular abscess. B, Abscess is incised with no. 11 blade. C, Beaks of hemostat are inserted through
Incision and opened so that beaks spread to break up any loculations of pus that may exist in abscessed
tissue .. 0, Small drain is inserted to depths of abscess cavity with hemostat. E, Drain is sutured into
place with single black silk suture.

reformation of the abscess cavity. It is important to remember that the surgical goal is to achieve ade~uate drainage. If endodontic opening of the tooth does not provide adequate drainage of the abscess, it is essential to
perform an I&D  The technique for I&D of a fluctuant vestibular abscess
is straightforward (Fig. 15:8). The preferred site for. theincision is. directly over the most dependent area, to encourage drainage. (When I&D procedures are performed extraorally, a more complex set of critetia must be met when selecting a site for the \p,ision.) Once the area of incision has been selected, a method of pain control must be used. Regional” nerve block anesthesia achieved by injecting an area away trom the site of the incision is
preferred. Alternatively, superficial Inflltration of local  anesthetic solution anterior and posterior to the area to be drained can be used. Before the actual incision of the abscess cavity is performed, consideration must be given to obtaining a specimen of the pus for culture and sensitivity (C&S) testing. If the decision is made. to perform a culture, the procedure is carried out as the initial portion of the surgery. Once the localized area has been anesthetized, a large-gauge needle, usually 18 gauge, is used for specimen collection. – A small syringe, usually 2 ml, is adequate. The surface mucosa is disinfected with a solution such as Betadine and dried W\\lt sterile gauze. The needle is then inserted into the abscess cavity, and 1 or 2 mL of pus is aspirated The syringe is held vertically, and any air bubbles contained in the syringe are ejected from it. The tip of the  needle is then capped with a rubber stopper and taken directly to the microbiology laboratory. This method for obtaining a specimen, permits both aerobic and anaerobic cultures and Gram’s staining. As discussed earlier, anaerobic
bacteria are almost always present in odontogenic infections, and therefore care must be taken to ‘provide the laboratory the best opportunity” to find them. Once the culture specimen is obtained, an incision is made with a no. 11. blade just through the mucosa and  submucosa into the abscess cavity (see Fig. 15-8). The incision should be short, usually HO more than 1 cm in length. Once the incision is completed, a closed curved hemostat is inserted through the incision into the abscess cavity. The hemostat is then opened in several directions to break up any small loculations or cavities of pus that have not been pened by the initial incision. The pus that drained out
,during this time should be aspirated into the suction and should not be allowed to drain into the patient’s mouth Once all areas of the abscess cavity have been oper  and all pus drained, a small drain is inserted to maintain the opening. The most commonly used drain for intraoral abscesses is a one-forth inch sterile Penrose draw A frequently used substitute is a small strip, of sterilized rubber dam. A piece of drain of adequate length to reach the depth of the abscess cavity is prepared and inserted into the cavity, using the hemostat. The drain is then sutured into place with a nonresorbable suture. The suture should be placed in viable tissue to prevent loss of the drain as the result of the suture tearing through. nonvital tissue. The dran should remain in place until all the drainage from the abscess cavity has topped, usually 2 to 5 days. Removal is done by simply cutting the suture and slipping the drain from the wound.Early-stage infections that initially appear as a cellulitis with soft, doughy, diffuse swelling do not typically  respond to I&D procedures. Surgical management of infections of this type is limited to removal of the necrotic pulp or removal of the involved tooth.

Prlnciplell: Evaluate State of Patient’s Host Defense Mechanisms

Prlnciplell: Evaluate State of Patient’s Host Defense Mechanisms 

Part of the evaluation of the patient’s medical history is designed to establish the patient’s ability to defend • against infection. Several disease states and several types of .drug use may compromise this ability. Compromised

FIG, 15--7 Well-localized abscess has crusted surface secondary to tissue necrosis. Mass is fluctuant on palpation.

FIG, 15–7 Well-localized abscess has crusted surface secondary to tissue necrosis. Mass is fluctuant
on palpation.

patients are more likely to have infections, and these  infections. often become serious more rapidly. Therefore to manage their infections more effectively, it is important to be able to discern those patients who may have a compromised host defense mechanism. .\]edical conditions that compromise host defenses. It is important to delineate those medical conditions that ay result in decreased host defenses. These compromises
allow, more bac teria to enter the tissues or to be mote active, or they prevent the humoral or cellular defenses from exerting their full effect. Several specificconditions  may compromise patients’ defenses (Box IS-I).
Severe, uncontrolled meta bolic diseases, such as severe diabetes, end-stage renal disease that leads to uremia, and severe alcoholism with malnutrition: result in decreased function of leukocytes, including decreased chemotaxis, phagocytosis, and bacterial killing, The’ second major group of host compromisers is diseases that interfere with host. defense mechanisms, such as leukemias, lymphomas, and many types of cancer. These result in decreased w ite cell function and decreased antibody synthesis and production. Patients taking certain drugs are also  ompromised.Cancer chemotherapeutic agents decrease circulating
white cell counts to extremely low levels, commonlybelow 1000 cells per milliliter. When this occurs patientswill be unable to defend themselves effectively againstbacterial invasion. Patients on immunosuppressive therapy,usually for organ transplantation or autoimmune diseases,are compromised. The common drugs in these categoriesare cyclosporin, corticosteroids, and azathioprine(Imuran). These drugs decrease T- and B-Iymphocytefunction and immunoglobultn productlon.Thus patient taking these medications are more likely to. have severe

BOX 15-1

Compromised Host Defenses

Uncontrolled metabolic diseases:
• Uremia
• Alcohofism
• M’alnutrition
• Severe diabetes
Suppressing diseases:
• leukemia
•• lymphoma
• Malignant tumors
Suppressing drugs: .
It . Cancer chemotherapeutic agents
D Immunosuppressive agents .

In summary, when evaluating a patient whose chief  complaint may be an infection, the patient’s medical history should be carefully examined for the presence of diabetes-evere renal disease, alcoholism with malnutrition,
I~ukemias and lymphomas, cancer chemotherapy, andimmunosuppressive therapy of any kind. When the patient’s history includes any of these, the patient with an infection must be treated much more vigorously, as
the infection may spread more rapidly. Early and aggressive surgery to remove’ the cause and more intense par- enteral antibiotic therapy must be considered. Additionally, when a patient with a history of one of
these problems is seen for routine oral surgical procedures, it may be necessary to provide the patient with prophylactic antibiotics to. attempt to prevent an infection from occurring .

BOX 15-2

Criteria for Referral to a Specialist

• Rapid progressive infection
• Difficulty in breathing
• Difficulty in swallowing
• Fascial space involvement .•
• Elevated temperature (greater than 1010 F)’
• Severe jaw trismus (less than 10 mm)
• Toxic appearance
• Compromised host defenses

Principle III: Determine Whether Patient Should Be Treated by General Dentist or Spectaist

Most odontogenic infections seen by the dentist can be  managed with the expectation of normal rapid resolution. Odontogenic infections, when treated with minor surgical procedures and commonly used antibiotics, almost always respond rapidly. However, some. odontogenic Infections
are potentially life threatening and require aggressive medical and surgical management. In these special situations, early recognition of the potential severity is essential and these patients should be-referred to a specialist,
usually an oral-rnaxllofactal surgeon, for definitive management. For some patients, hospitalization will be  – required, whereas others will be managed as outpatients. When a patient with an odontogenic Infection comes
for treatment, the dentist must have a set of criteria by which to judge the seriousness of the infection (Box 15-2). If some or all of these criteria are met, immediatereferral must be considered.Three main criteria suggest immediate referral to a specialist.The first· is a history of a ,’apidl), progressing intecn I. This means that the lnfectton began 1 or 2 days
before the interview and is growing rapidly worse, withincreasing swelling, pain, and associated signs and symptoms. This type of odontogenic infection may spread toareas in which it is potentially llfethreatenmg and therefore-must be treated aggressively. The second criterion is
difficllity ill breathillg.·Patients whohave severe swelling btthe soft tissue of the upper airway as the result of infectionmay have difficulty maintaining a patent airway. lnthese situations the patient often cannot lie down, has
_difficulty with speech, and is obviously distressed withthe breathing difficulties. This patient should be referreddirectly to an emergency room, because immediate surglcalattention may be necessary to maintain an intact airway:The third urgent criterion Is difficult}’ III swallowing.
Patients who have s’..r•elltng and trismus rnav have dlfflculty
swallowing their saliva. This is an ominous sign,because difficulty in swallowing frequently indicates anarrowing of the oral pharynx and potential for acute airwayembarrassment. This patient should also be referred to the hospital emergency room, because surgical intervention
may be required for airway maintenance.Several other criteria should indicate referral to the

Principle I: Determine Severity of Infection

Principle I: Determine Severity of Infection

Most odontogenic infections are mild and require only minor therapy. When the patient comes for treatment, the initial goal is to assess the severity of the infection. This determination is based on a complete history of the current infectious illness and a physical examination. Complete history. The history of the patient’s infection follows the same general guidelines as any history. The initial purpose is to find out the patient’s chief complaint, Typical chief complaints of patients with infections are, “I have a toothache,” “My.jaw is swollen,”.or “I have a gum boil in my mouth.” The complaint should be recorded in the patient’s own words. The next step- in taking of the history is determining how long the Infection has been present. First, the dentist should inquire as to time of. onset of the infection. How long ago did the patient first have symptoms of pain, swelling, or drainage, which indicated the beginning of’ the infection? The duration of the infection is then discussed. Have the symptoms of the infection been constant, have they waxed and waned, or has the patient

FIG. 15-2 Relationship of point of bone perforation to muscle attachment will determine fascial space involved. A, When tooth apex is lower than muscle attachment, vestibular abscess results. B, If apex is higher than muscle attachment, adjacent fascial space will be involved.

FIG. 15-2 Relationship of point of bone perforation to muscle attachment will determine fascial
space involved. A, When tooth apex is lower than muscle attachment, vestibular abscess results. B, If
apex is higher than muscle attachment, adjacent fascial space will be involved.

FIG. 15-3 Vestibuiar abscess arising from maxillary incisor. Overlyinq mucosa is thin because pus is near surface .•

FIG. 15-3 Vestibuiar abscess arising from maxillary incisor. Overlyinq mucosa is thin because
pus is near surface 

11

 

steadily grown worse since the symptoms were first noted? Finally, the practitioner should determine the rapidity of progress of the infection. Has the infection process progressed rapidly over a few hours, or has it gradually increased in severity over several days to a week? The next step is eliciting the. patient’s symptoms. Infections are actually a severe Inftarnma:-x j response, and the typical signs of inflammation are clinically easily discernible. These signs and symptoms are dolor (i.c., pain), tumor (i.e., swelling), calor (i.e., warmth), rubor (i.e., erythema, or redness), and functio laesa (i.e., loss of function.) .The most common complaint is dolor. The patient . should-be asked where the pain actually started and how the pain has spread since it was first noted; the second dsign is tumor. Swelling is a physical finding that is sometimes subtle and not obvious to the  although it is to the patient. It is important that the dentist  sk the patient to describe any area of swelling, where it is, and how large it feels. “The third characteristic of intecnou is calor. The patient should be asked if the
area feels hot. Rubor of the overlying area is the next characteristic:
to be discussed. The patient should be asked’ if there has been or currently is any change in colorcially redness, over the area of the infection, Functio laesa should then be checked. When inquiring about this chactenstic, the dentist should ask about trismus and difficlifty in swallowing, breathing, Of chewing, Finally, the dentist should ask how the patient feels in general. Patients who feel fatigued, hot, sick, and generally out of sorts are said to have malaise. Malaise u_suaUy indicates a generalized reaction to a  moderate-to-severe infection (Fig, 15-5). – In the next step the dentist inquires about treatment.The dentist should ask about previous professional treatment a(‘jl self-treatment, Many patients will “doctor”
themselves with leftover antibiotics, hot soaks, and avariety of other home remedies, Occasionally, a dentistsees a patient who received treatment in an emergency room 2 or 3 days earlier and was referred to a dentist by
the emergency room physician, The patient may haveneglected to follow that advice _until the infection became rather severe. The patient’s medical history should be obtained in the usual manner by interview or by self-dministered questionnaire. Physical examination. The first step in the physical examination is to coUect the patient’s vital signs. Thisincludes temperature, blood pressure, pulse rate, and respiratory rate. The need for evaluation of temperature is obvious. Patients who have systemic involvement of infection Will have elevated temperatures. Patients withsevere infections will have temperatures elevated to 101Q
to 102 ° F (38.3° to 38.8° C). The’ patient’s pulse rate will-increase as the patient’s temperature increases. Pulse rates of up to 100 beats pel
minute are not uncommon in patients with infections. f pulse rates increase above 100 beats per minute, the patient may have a severe infection and-should be treated more aggressively. ‘The vital sign that varies the least with infection is the patient’s blood pressure. Only if the patient has significan  pain and anxiety ‘,,;ilI there be a mild elevation insystolic blood pressure Finally, the patient’s respiratory rate should be closelyobserved. One of the major considerations in odontogenic infections is the potential for upper airway obstruction as a result of extension of the infection into fascial spaces in the area of the pharynx. As respirations are monitored, the
dentist should carefully check to ensure that the upper airwayis clear and that breathing is without difficulty. The normal respiratory rate is 14 to 16 breaths per minute.Patients with mild-to-moderate infections have elevated  espiratory rates of up to 18 to 20 breaths per minute.
Patients Who have normal vital signs with only a mild emperature elevation usually have a mild infection that can be readily treated. Patients who-have abnormal vitalsigns with elevation of temperature, pulse rae, and espiratoryrate are more likely to have serious infection andrequire more elaborate therapy. Once vital signs have been taken, attention ‘should be
turned to physical examination of the patient. The initialportion of the physical examinationshouJd be inspectionof the patient’s general appearance. Patients who havemore than a minor, localized infection have an appear-

FIG. 15-5 Patient with severe infection and elevated temperature, pulse rate, and respiratory rate. The patient feels sick and tired; he _ has a "toxic appearance."

FIG. 15-5 Patient with severe infection and elevated temperature,
pulse rate, and respiratory rate. The patient feels sick and tired; he
_ has a “toxic appearance.”

ance of fatigue, feverishness, and malaise. This is a “toxic appearance” (see Fig. 15-5). •  he patient’s head and neck should be carefully examined
for signs of i nfection and the patient inspected for any evidence of swelling and overlying erythema. The patient should be asked to open the mouth widely, swallow, and take deep breaths so that the dentist can check I
for dvsfunction. Areas of swelling must be examined by palpation. The
dentist should gently touch the area of swelling to check for tenderness, amount of local warmth or heat, and the character of the swelling. The character of the swelling varies from feeling very soft and almost normal through a firmer swelling (described as having a dOl/ghy feeli/lg) to an even firmer or hard swelling (described as feeling induratedi. An indurated swelling has the same firmness as a tightened muscle .. Another characteristic swelling texture is [luctuant. Fluctuance is the feeling of a fluid-filled balloon. Fluctuant swelling almost always indicates an
accumulation of pus in the underlying tissues. The dentist then performs an’ intraoral examination to try to find the specific cause of the infection, There may be severely carious teeth, an obvious periodontal abscess,

 

 

 

 

PRINCIPLES OF THERAPY OF ODONTOGENIC INFECTIONS

PRINCIPLES OF THERAPY OF ODONTOGENIC INFECTIONS

This section discusses the management of the odontogenic infection. A series of principles are discussed .that are useful in treating patients who come to the dentist with infections related to the teeth and gingiva. The clinician must keep in mind the information in the preceding two sections of this chapter to understand these prtnciples

NATURAL HISTORY OF PROGRESSION OF ODONTOGENIC INFECTIONS

NATURAL HISTORY OF PROGRESSION OF ODONTOGENIC INFECTIONS

Odontogenic infections have.two major origins: (1) periapical, as a result of pulpal necrosis and subsequent bacterial invasion into the periapical tissue, and (2) period on trial periodontal as a result of a deep periodontal pocket that allows inoculation of bacteria into the underlying sof tissues.
Of these two, the periapical origin is the most (ommon in odontogenic infections. Necrosis of the dental pulp as a result of deep caries allows a pathway for bacteria to enter the periapical tissues. Once this tissue has become inoculated with bacteria and an active infection is established, the infection will spread equally in all directions but preferentially along the lines of least resistance. The infection will spread through the cancellous bone until it encounters a cortical plate. If this cortical plate is thin, the infection erodes through the bone and enters the soft tissues. Treatment
of the necrotic pulp by standard endodontic therapy or extraction of the tooth will resolve the infection. ‘Antibiotics alone may stop the infection, but the infection is likely to recur when antibiotic therapy is ended
and the tooth is not treated. When the infection erodes through the cortical plate of the alveolar process, it appears in predictable anatomic locations. The location of the infection from a specific tooth is determined by the following two major factors: (1) the thickness of the bone overlying the apex of thetooth and (~) the relationship of the site of perforation of bone to muscle attachments of the maxilla and mandible. Fig. 1-5-1 demonstrates how infections perforate through bone into the overlying soft tissue. In Fig. 15-1, A, the-labial bone’ overlying the apex of the tooth is thin compared with the bone on the palatal aspect of the tooth. Therefore’ as the infectious process spreads it goes into the labial soft tissues. In Fig. 15-1, B, the tooth is severely. flared, Which results in thicker labial bone and a  relatively thinner palatal bone. In ·this situation as the infection spreads through the bone into the soft tissue, the infection is expressed as a palatal abscess.
Once the infection has eroded through the bone, the .precise location of the soft’ tissue infection will be determined by the position of the perforation relative to the muscle attachments. In Fig. 15-2, AI the infection has eroded through to the labial aspect of the tooth and infe

FIG. 15~-1 When infection erodes through bone, it will enter soft tissue through thinnest bone. A, Tooth apex is near thin labial bone, so infection erodes labially, B, Right apex is near palatal aspect, so bone will be perforated.

FIG. 15~-1 When infection erodes through bone, it will enter soft tissue through thinnest bone.
A, Tooth apex is near thin labial bone, so infection erodes labially, B, Right apex is near palatal
aspect, so bone will be perforated.

rior to the attachment of the buccinator muscle, which results in an infection that appears as a vestibular abscess.  In Fig. 15-2, B, the infection has eroded through the bonesuperior to the attachment-of the buccinator muscle and will be expressed as an infection of the buccal space. Infections from most maxillary teeth erode through  he labiobuccocortical-plate. They also erode through the bone below the attachment of the muscles that attach to the maxilla, which means that most maxillary dental abscesses appear initially as vestibular abscesses. Occasionally, a palatal abscess from a severely inclined lateral incisor or palatal root of a maxillary first molar will occur. Likewise, on occasion a long maxillary canine-tooth will
erode thrugh the bone superior to the insertion of the  levator anguli oris and will cause a canine space infection.More commonly, the maxillary molars will have  infections that erode through the bone superior to the’
insertion of the buccinator muscle, which result in a buccal space infection. In the mandible, infections of the incisors, canines, and premolars usually erode through the labiobuccocortical plate and above the associated musculature, resulting in vestibular abscesses. Molar teeth infections erode
through the linguocortical bone more frequently than the anterior teeth. First-molar infections will drain either buccally or lingually. The second molar can perforate either buccally or lingually (but usually lingually), and
third molar infections almost always erode through the linguocertical plate. The mylohyoid muscle will determine whether infections that drain lingually go into the sublingual or submandibular space. The most common odontogenic infection is a vestibular abscess (Fig. 15-3). Occasionally, patients do not seek treatment for these infections, and the process will rupture spontaneously ‘and drain, resulting in resolution of the Infection.The infection will recur if the site of spont aneous drainage closes. Sometimes the abscess establishes a chronic sinus tract that drains to the oral cavity (Fig. 15-4). As long as the sinus tract continues to drain, the
patient will experience no pain. Antibiotic administration  administration will usually cause a cessation of the drainage, but when .antibiotics are stopped, ·the drainage will recur. Definitive treatment of a chronic sinus tract requires treatment of the original problem, that is, the necrotic pulp treated by endodontic therapy or by extraction of the tooth.

 

 

MICROBIOLOGY OF ODONTOGENIC INFECTIONS

The bacteria that cause infection are most commonly part of the indigenous bacteria that normally live on or in the host. Odontogenic infections are no exception, because the bacteria that cause odontogenic infections are part of the normal oral flora: those that comprise the bacteria of plaque, those found on the mucosal surfaces, and those ,found in the gingival sulcus. They are primarily aerobic gram-positive cocci, anaerobic gram-positive cocci, and anaerobic gram-negative rods. These bacteria cause a variety of common diseases, such as dental caries, gingivitis, and periodontitis. When these bacteria gain access to deeper underlying tissues, as through a necrotic dental pulp or through a deep periodontal pocket, they cause
odontogenic infections. Many carefully performed microbiologiC studies of
odontogenic infections have demonstrated the microbiologic composition of these infections. Several important factors must be noted. First, almost all odontogenic infections. are caused by multiple bacteria. The polymicrobial
nature of these infections makes it important that the clinician understand the variety of bacteria that are likely to

TABLE 15-1

Causative Organisms

Causative Organisms”
Aerobic’
Anaerobic only’
Mixed’
Num~er I:!f Patients
28
133
243
7
33
60

In 404 patients; data from Aderhold L, Konthe H, Frenkel GThe baCteriology of dentogenous pyogenic infections, OralSu:g 52:583,
1981Bartlett JG,O’Keefe P: The bacteriology of perimandibular space infections, J 6ral Surg 50: 130, 1980; ‘Chow Aw, Roser 5M, Brady FA: Orofacial odontogenic infections, Ann Intern Med 88:392, 978; lewis MAO et al: Prevalence of penicillin resistant bacteria in ~ e suppurative oral infection, J Antimicrob Chemothe; 35B:785, 5- McCowan DA: Is antibiotic prophylaxis required far dental’ oat~~.”.o’Ith joint replacement? Br Dent J 158:336, 1985; Norden ~,,: PrNentiof’l of bone andjomt infections, Am J Med78:229, i985. cause the infection. In most odontogenic intectlons the
laboratory can identify an average of five species of bacteria. It js Dot unusual for as many as eight different species to be identified in a given infection. On rare occasions a single species may be isolated. A second important factor is the anaerobic-aerobic characteristic of the bacteria causing odontogenic infec- . < tions. Because the mouth flora is ,a combination of aerobic and anaerobic bacteria, it is not surprising to find that most odontogenic infections have both anaerobic and aerobic bacteria. Infections caused by only aerobic. bacteria probably account for 5% of all odontogenic infections. Infections caused by only anaerobic bacteria make
up about 35% of the infections. Infections caused by both anaerobic and aerobic bacteria comprise about 60% of all odontogenic infections (Table 15-1).   The aerobic bacteria that cause odontogenic infections consist of many species (Table 15-2).<The most common causative organisms are streptococci, which comprise about 90% of the aerobic bacterial species that cause odontogenic infections. Staphylococci account for about
5% of the aerobic bacteria, and many miscellaneous bacteria contribute 10/0 or less. Rarely found bacteria include group D Streptococcus organisms, Neisseria spp., Corynebac

TABLE 15-2

Microorganisms Causing Qdontogenic Infections”

Organism, Percentage
Aerobict 25 .
Gram-positive cocci 85
Streptococcus spp: 90
Streptococcus (group D) spp. 2
Staphylococcus spp. 6
Eikenella spp. ‘:2
Gram-negative cocci (Neisseria spp.) 2
Gram-positive rods (Corynebacterium spp.) 3
Gram-negative rods (Haemophilus spp.) . 6
Miscellaneous and undifferentiateCl 4
Ancierobict 75
Gram-positive cocci 30
Streptococcus spp. 33
Peptostreptococcus spp. 65
Gram-negative cocci (Veillonella spp.) 4
Gram-positive rods 14
Eubacterium spp.
Lactobacillus spp.
Actinomyces spp.
Clostridia spp.
Gram-negative rods 50
Bacteroides 75
Fusobacterium spp. 25
Miscellaneous 6

The anaerobic bacteria that cause infections include an even greater variety of species (see Table 15~2). Two main groups, however, predominate. The anaerobic grampositive cocci ‘account for about one third of the bacteria.
These cocci are anaerobic Streptococcus and Peptostreptococcus. The’ gram-positive rods Eubacterium and LactbbacilIus organisms are most commonly found in this group . . The gram-negative anaerobic rods are cultured in about  alf of the infections. The Prevotella and Porphyromonas
(previously Bacteroides) spp. account for a out 75% ofthese, and  usobacterium organisms account for 25%. Of the anaerobic bacteria, several gram-positive cocd (i.e., anaerobic Streptococcus and Peptostreptococcus spp.) and  ram-negative coos (i.e., Prevot6lla and Fusobacterium spp.) play a more important pathogenic roe. The anaerobic
gram-negative cocd and the anaerobic gram-positive rods appear to have little or no role in ‘the cause of odontogenic infections; instead they appear to be opportunistic organisms. The method by which mixed aerobic and anaerobic  bacteria cause infections i~ known with some certainty. . After init al inoculation into the deeper tissues, the more :-waslve organisms with higher virulence (i.e., the aerobic -ireptococcus spp.) begin the infection process, initiating a cellulitis type of infection. The anaerobic bacteria will
then also grow, and   s the local reduction-oxidation potential is lowered (because of the growth of the aerobic bacteria),  naerobic bacteria become more prominent. As the infection reaches a more chronic, abscess stage, the anaerobic bacteria predominate and eventually become the exclusive causative organisms. Early infections appearing initially as a cellulitis may be characterized as  erobic streptococcal infections, and late, chronic abscesses may be characterized as anaerobic infections ..

Principles of Management and Prevention of Odontogenic Infections

CHAPTER OUTLINE

MICROBIOLOGY OF ODONTOGENIC INFECTIONS
NATURAL HISTORY OF PROGRESSION OF
ODONTOGENIC INFECTIONS
PRINCIPLES ‘OF THERAPY OF ODONTOGENIC INFECTIONS
Principle I: Determine Severity of Infection
Complete History
Physical EXamination .
Principle II: Evaluate State of Patient’s Host Defense
Mechanisms ‘ .
Medical Conditions that Compromise Host
Defenses
Prindple III: Determine Whether Patient Should Be
Treated by General Dentist or Specialist
Principle IV: Treat Infection Surgically
Principle V: Support Patient Medically
Principle VI: Choose and Prescribe Appropriate
Antibiotic .
Determine Need for Antibiotic Administration
Use Empiric Therapy Routinely
Use Narrowest-Spectrum Antibiotic
Use Antibiotic with Lowest Incidence of Toxicity
and Side Effects .
Use Bactericidal Antibiotic, if Possible
Be Aware of the Cost of Antibiotics
Summary .
Principle VII: Administer Antibiotic Properly
Prlnclple VIII: Evaluate Patient Frequently
PRINCIPLES OF PREVENTION OF INFECTION
PRINCIPLES OF PROPHYLAXIS OF WOUND INFECTION
Principle I: Procedure Should Have Significant Risk of
Infection .
Prlnciplell: Choose Correct Antibiotic
Principle III: Antibiotic Plasma Level Must Be High
Principle IV: TIme Antibiotic Administration Correctly
Principle V: Use Shortest Antibiotic Exposure that Is
Effective
Summary .
PRINCIPLES OF PROPHYLAXIS AGAINST METASTATIC
INFECTION
Prophylaxis Against Infectious Endocarditis
Prophylaxis in Other Cardiovascular Cases
Prophylaxis Against Total Joint Replacement Infection

One of the most difficult problems to manage in dentistry is an odontogenic infection. These . infections may range from low-grade, welllocalized
infections that require only minimal treatment to severe, life-threatening fascial space infections. Although the overwhelming majority of odontogenic infections are easily managed by minor surgieal proceprocedures and supportive medical therapy that includes
antibiotic administration, the practitioner must c~nstantly bear in mind that these infections occasionally become severe in a very short time. .
This chapter. is divided into several sections. The first section discusses the typical microbiology involved in odontogenic infections. Appropriate therapy of odont gernc infections depends on a clear understanding of the
causative bacteria. The second section discusses the natural history of odontogenic infections. -When infections occur, they may erode through bone and into the overlying soft tissue. Knowledge of the usual pathway of infection from the teeth and surrounding tissues through the bone and into the overlying soft tissue planes is essential when planning appropriate therapy The third section ‘of this chapter deals with the principles of.management of odontogenic infections. A series of principles are discussed, with consideration of the microbiology and typical pathway
of infection. The chapter concludes with a section on prophylaxis against infection. The prophylaxis of wound infection and of metastatic infection is discussed.

Infections

Odontogenic infections are usually mild and easily treated and may only requlre the administration of an antibiotic. Conversely, odontogenic infections may be more complex and require an incision and drainage, or they may be complicated and require that the patient he admitted to the hospital. Some infections that occur in the oral cavity are  preventable0 if the surgeon uses appropriate antibiotic prophylaxis. This section . presents the principles of infection management and prevention in  dental patients. . Chapter 15 describes the basic management techniques, including surgeryand antibiotic administration, for the treatment of odontogenic infections. This chapter also discusses the principles of antibiotic prophylaxis for the prevention of both wound infection and distant metastatic infection, such as infectious endocarditis. ‘
Chapter 16 presents an overview of complex odon togenic infections that
involve fascial spaces and may require hospitalization of the patient  ortreatment. Osteomyelitis and other unusual infections are also discussed.
Chapter 17 presents the indications, rationale, and technical aspects of surgical endodontics, Although periapical surgery is occasionally necessary for successful endodontic management, it is necessary for the clinician to be wise in deciding when to choose this treatment modality. Therefore the discussion of the Indications and contraindications for endodontic surgery is extensive, and the technical aspects of surgical endodontics are profusely illustrated. Chapter 18 presents information about patients at risk for infection and other comprising problems that are callsed by patient host defense compromise as the result of radiotherapy or cancer chemotherapy. These patients are susceptible to a variety of problems, and the prevention and management of these problems are discussed.  Chapter 19 describes maxillary sinus problems that arise secondary  to odontogenic infections, and other problems. Although general practitloners rarely see patients with these problems, they may have to provide diagnoses before referring these patients to the appropriate professional fq~ definitive care.Finally,Chapter 20 discusses salivary gland diseases, primarily the obstructive and infectious types. The major diagnostic and therapeutic modalities used in managing these problems are discussed,