NEET MDS Lessons
Oral Pathology
Chronic Osteomyelitis
- As soon as pus drains intra or extraorally, condition ceases to spread and chronic phase commences.
- Infection is localized but persistent as bacteria are able to grow in dead bone inaccessible to body’s defenses.
Clinical features
- Primary – insidious in onset , slight pain , gradual increase in jaw size.
- Secondary - Pain is deep pain and intermittent, temperature fluctuations , pyrexia , cellulitis eventually leading to abscess
- New bone formation leads to thickening causing facial asymmetry.
- Thickened or “wooden” character of bone in cr sec osteomyelitis.
- Eventually cures itself as the last sequestra is discharged.
Radiographic Features
- Trabeculae in the involved area become thin or appear fuzzy & then lose their continuity.
- After some time “moth eaten” appearance is seen
- Sequestra appear denser on radiographs.
- Where the subperiosteal new bone formation , the new bone is superimposed upon that of jaw, “fingerprint” or “orange peel” appearance is seen
- Cloacae seen as dark shadows passing through opacity.
Histologic features
- Areas of acute and subacute inflammation in the cancellous spaces of the necrotic bone.
- Foci of acute inflammation
- Active osteoclastic resorption of bone noted in peripheral portions
Chronic Subperiosteal Osteomyelitis
- Cortical plate deprived of its blood supply undergoes necrosis, underlying medullary bone is slightly affected.
- Multiple small sequestra form, eventually discharged through sinuses with pus.
- Following extrusion of sequestra, healing occurs.
- Spontaneous drainage poor in submassetric area.
- Much of body of mandible is lost due to poor central blood supply of the region.
D/D
- Paget’s disease – particularly wen periosteal bone is involved
- Fibrous dysplasia
- Osteosarcoma
Chronic sclerosing osteomyelitis
– focal
- diffuse
Focal Sclerosing Osteomyelitis
Clinical features
- Most commonly in children and young adults, rarely in older individuals.
- Tooth most commonly involved is the mandibular third molar presenting with a large carious lesion.
- No signs or symptoms other than mild pain associated with infected pulp.
Radiographic features
- Entire root outline always visible with intact lamina dura.
- Periodontal ligament space widened.
- Border smooth & distinct appearing to blend into surrounding bone
D/D for focal sclerosing osteomyelitis
- Local bone sclerosis
- Sclerosing cementoma
- Gigantiform cementoma
Treatment & prognosis
- Affected tooth may be treated endodontically or extracted.
- Sclerotic bone not attached to tooth and remains behind after tooth is removed.
- This dense area may not get remodeled.
- Recognizable on bone years later and is referred as bone scar.
Diffuse Sclerosing Osteomyelitis
- May occur at any age, most common in older persons, esp in edentulous mandibles
- vague pain, unpleasant taste.
- Many times spontaneous formation of fistula seen opening onto mucosal surface to establish drainage
- Slowly progressive, not particularly dangerous since it is non destructive & seldom produces complications
Radiographic features
- Diffuse patchy, sclerosis of bone – “cotton wool” appearance
- Radiopacity may be extensive and bilateral.
- Due to diffuse nature, border between sclerosis & normal bone is often indistinct
D/D for DIFFUSE sclerosing osteomyelitis
FLORID OSSEOUS DYSPLASIA
SCLEROTIC CEMENTAL MASSES
TRUE CHR DIFFUSE SCLEROSING OSTEOMYELITIS
FIBROUS DYSPLASIA
Treatment & Prognosis
- Resolution of adjacent foci of chronic infection often leads to improvement.
- Usually too extensive to be removed surgically,
- Acute episodes treated with antibiotics.
Acute suppurative osteomyelitis
- Serious sequela of periapical infection.
- Leads to spread of pus through the medullary cavities of bone.
- Depending upon the main site of involvement of bone, can be of two types-
- Acute intramedullary
- Acute subperiosteal
Acute Intramedullary Osteomyelitis
CLINICAL FEATURES:
- Patient experiences dull , continuous pain , indurated swelling forms over the affected region of jaw involving the cheek , febrile.
- When mandible involved, loss of sensation occurs on lower lip on affected side due to involvement of inferior alveolar nerve.
- Teeth become loose later along with tender on percussion
- Pus discharge , trismus , foul smell , regional lymphadenopathy , weakness
RADIOGRAPHIC FEATURES
- Earliest radiographic change is that trabeculae in involved area are thin, of poor density & slightly blurred.
- Subsequently multiple radiolucencies appear which become apparent on radiograph.
- In some cases there is saucer shaped area of destruction with irregular margins.
- Loss of continuity of lamina dura, seen in more than one tooth.
HISTOLOGIC FEATURES:
- Dense infiltration of marrow by polymorphonuclear leukocytes.
- Bone trabeculae in involved site (sequestrum) are devoid of cells in the lacunae.
- separation of considerable portions of devitalized bone.
Acute Subperiosteal Osteomyelitis
CLINICAL FEATURES
- Pain , febrile condition , i/o and e/o swelling , parasthesia
- Bone involvement limited to localized areas of cortex.
- Pus ruptures rapidly through the overlying cortex, tracks along the surface of mandible under the periosteal sheath.
- Elevation of periosteum from cortex is followed eventually by minute cortical sequestration.