Predisposing factors:

1. Reduced host resistance:

2. Reduced jaw vascularity:


  • Pus accumulates in marrow spaces
  • Increases intramedullary pressure
  • Compress vasculature
  • Decreased blood supply
  • Decreased nutrients and hypoxia
  • Necrosis of bone
  • Sequestrum
  • Spreads to subperiosteal area
  • Perforation
  • Fistula to skin and oral mucosa


  1. G+ve = S. aureus, S. albus, Hemolytic strep
  2. G-ve = Klebsiella, Pseudomonas, Proteus, E. coli
  3. Anaerobes = Pepto-streptococcus, bacteroid, fusobacteria


  • Localized pus + lymphocytes + plasma cells
  • Dead bone – empty lacunae ( no osteoclasts)
  • Pus found in medulla
  • Periosteum distended by pus
  • Osteoblastic and osteoclastic activity
  • Involucrum – New bone
  • Sequestrum – Dead bone
  • Onion skin appearance (in chronic)

Clinical classification

1. Anatomical location:

  • Intramedullary
  • Subperiosteal
  • Periosteal

2. Duration & severity:

  • Acute
  • Chronic

3. Presence/ absence of suppuration:

  • Suppurative:
    • Acute
    • Chronic
      • 1ry (denovo)
      • 2ry (low grade infection)
    • Infantile
  • Non suppurative:
    • Chronic – Moth eaten on x-ray
    • Osteoradionecrosis
    • Garre’s osteomyelitis – Onion skin on x-ray
      • Chronic osteomyelitis with proliferative periostitis
      • Young people
      • Increased reactive new bone formation
    • Atypical osteomyelitis:
  • Others:
    • Chronic diffuse sclerosing – Old people, super infection of florid COD
    • Chronic focal sclerosing – Young people with carious teeth

Clinical features

  • Pain
  • Swelling
  • Pyrexia
  • Lymphadenopathy
  • Periosteum distended with pus
  • Discharging sinus
  • Rampant caries
  • Periodontitis
  • Anesthesia, paresthesia of lower lip
  • Teeth may become mobile, tender
  • Pus exudes from sockets or gingival margin
  • Difficult to open mouth – due to edema of muscle


1. Early lesion:

  • Basic incision and drainage
  • Supportive therapy: Rehydrate, nutritional diet, hyperbaric O2

2. Severe lesion:

  • Antibiotic
  • Surgical debridement
  • Irrigation
  • Sequestrectomy/ resection ± decortication


Acute osteomyelitis


  • Periapical inflammation
  • Open fracture (involving PDL socket/ penetrating contaminated injury)
  • ANUG
  • Pericoronitis

Predisposing factors:

  • Reduced host resistance
  • Paget’s disease
  • Radiation damage
  • Trauma including gunshot wounds


  • Adult males (Fights)
  • Mandible (has low blood supply)


  • Loss of trabeculae pattern
  • Areas of radiolucency – bone destruction
  • Moth eaten appearance
  • 30% osteolysis needed for x-ray changes


  • Anesthesia of lower lip
  • Pathological fractures – rare
  • Chronic osteomyelitis
  • Cellulitis/ septicemia in immunocompromised patients

Chronic non-suppurative osteomyelitis


  • Acute osteomyelitis
  • Radiation
  • Persistent low-grade infections

Predisposing factors:

  • Similar to acute
  • Local bone sclerosis
  • Localized reaction of bone to inflammation or infection

Histology: Marrow spaces devoid of pus and bacteria


TypeAcuteChronicGarre’sChronic diffuse sclerosingChronic focal sclerosing
EtiologyStaph, strepStaph, strepStaph, strep, Sequel of tooth abscess/extractionLow grade infection, pulpitis, PDL diseaseLow grade focal bone irritation eg. pulpitis
ClinicalPain, pyrexia, lymphadenopathy, leukocytosisVariable pain, swelling, discharging sinusLower molars of children, adolescentsPain, discharging sinus, usually mandibleAsymptomatic, found on routine exam
X-rayNo changeMoth eaten radiolucencyMottled radiolucency, onion skin patternGeneralized opacificationOpaque mass at root apex
SclerosisPeriosteal reaction at lower border of mandiblePeriapical/ periodontalPeriapical, non vital tooth
AgeAdolescentsAdultChildren and young adults
HistopathologyParallel layers of cellular woven bone, small sequestraSclerosing + remodeling, scant marrow space, adjacent inflammationDense sclerotic
Types of osteomyelitis

NB: Sequestra separate spontaneously or incorporated into healing bone


  • Spread of infection in abnormal bone (eg. Paget’s disease)
  • Infection with low virulence organisms/inadequate antibiotic treatment – long standing osteomyelitis with sclerosis of viable bone

Bisphosphonate induced osteomyelitis

  • Bisphosphonate suppresses osteoclast activity and reduces blood flow
  • Therefore inhibits bone resorption
  • Bisphosphonates lessens the bone destruction (caused by malignancy) but there is an increased susceptibility to ischemia
  • High dose can cause osteonecrosis
  • Therefore before bisphosphonate is administered, the following should be considered:
  1. Potential problems to be eliminated
  2. At risk patient should be identified by history taking and predisposing factors
  3. Surgical procedures should be avoided for as long as possible after administration
  4. Extractions should be followed by antibiotics and mouth rinse until socket has healed

Risk factors:

  • IV high dose bisphosphonate treatment usually for bone metastases/hypercalcemia of malignancy
  • Radiotherapy to head and neck
  • Immunosuppression from chemotherapy/steroids
  • Anaemia
  • Dental surgery/sepsis, ill fitting dentures and poor oral hygiene
  • Female patient
  • Elderly patient
  • Smoking


  • Non healing extraction socket/asymptomatic exposed bone
  • Do not respond to conservative treatment
  • Extractions could precipitate onset
  • Once infection is established – acute/chronic osteomyelitis may ensue – this depends on both virulence or organism and host resistance
  • Because bisphosphonate reduce bone turnover, sequestra develop very slowly


  • Oroantral and cutaneous fistulae
  • Suppuration


  • Osteomyelitis caused by radiotherapy
  • Radiotherapy causes narrowing of blood vessels therefore decreased blood supply to bone
  • Diagnosis based on history of radiotherapy
  • Once infection develops – course is similar to conventional osteomyelitis
  • But bone is more fragile due to radiotherapy – therefore infection more extensive, and sequestration is delayed


  • Extraoral sinuses
  • Pathological fracture
  • Pain that is difficult to manage (even when using opioids)