This document outlines various special investigations that may be used in oral medicine to aid in diagnosis. It discusses tests such as imaging techniques like CT, MRI, ultrasound and sialography. It also covers biopsies including incisional, excisional, and fine needle aspiration. Microbiology tests like cultures and smears are mentioned. Hematology, blood chemistry, and other blood tests that can provide information on conditions like anemia, infections, and metabolic diseases are also summarized. The document provides details on the indications, advantages, and disadvantages of these different diagnostic tests and investigations.

1. Special
Investigations

2. Principles of Investigations
Personal Data.
Present complain.
Family history.
Social history.
Medical history.
Vital signs.
Clinical examination.
Differential Diagnosis
Special
Investigations
Final Diagnosis
Plan of treatment

3. Special Investigations
 Special investigation should only be requested to answer specific question
 Some investigation have high specification and sensitivity for particular Disease
 Few diseases like mumps may be diagnosed on the basis of a single test, but
others such as Sjogren’s syndrome may require many tests
Haematology
Blood chemistry
and electorlyte
test
Microbiology
Culture
Smear
Viral Culture
ImmunofluorescentHistopathology
(1) Biopsy
Surgical biopsy
Fine needle aspiration
(2) Exfoliative cytology
IncisionalExcisional
Imaging.
Conventional
Radiography
Computerized
Tomography(CT)
Magnetic Resonance
Imaging (MRI)
Ultra sound
Sialography
Thick needle/ core biopsy
Sialochemistry
All special Investigation needed in Oral
Medicine
Immunohistochemistry
&
Molecular biological test.

4. * Percussion test
* Palpation test
* Thermal changes test:
- Heat test
- Cold test
* Electric sensitivity testing
Clinical Investigations

5. Imaging
• Conventional Radiography:
– Intra-oral [occlusal, Periapical, bitewing]
– Panorama
– Cephalometric
• Computerized tomography (CT scan)
• Sialography & Arteriography
• MRI
• Ultrasound
Indication:
To detect: Caries – Periodontal disease – Periapical lesion. Neoplasm –
cysts – TMJ disease - Results of trauma to teeth or Jaws – to locate foreign
objects and to find impacted teeth.

6. Computerized tomography (CT):
CT Scanning provides tomographic images (Section) of high clarity in any plane
Advantages:
Disease in the Maxillofacial complex
CT scanning images of cysts
CT is sensitive for neoplasm
Disadvantages:
Expensive
Not always available
High x-ray dose
Less information on soft tissue lesion
Radio-opaque dental restoration cause artifact shadow
It produces clear tomographic images particularly for soft tissue lesion, it can
differentiate between two densities of soft tissues 4 times better than CT Scan
and 40 times better than conventional radiograph, no x-ray dose is present in
this method.
Disadvantages: - MRI is expensive and limited availability
- Does not image the bone.
- Long imaging time.
Magnetic Resonance Imaging (MRI)

7. Ultrasound examinations use high frequency sound pulses. Ultrasound requires
expertise.
Indication:
-Used to determine whether any structure is solid or cystic [solid
objective absorb almost all of the sound and are less echoes than the
soft tissue].
- Examination of salivary gland (Tumors, cyst, stones). Detect the lesion
in the thyroid gland and neck. Evaluation of lymph node, post surgical
edema and hematoma.
Ultrasound

8. Radio-opaque contrast agent like (Iodine derivative) is infused into the ductal
system of salivary gland. There is low radiation exposure.
Disadvantages:
•There is some discomfort or pressure when the contrast material is injected
into the ducts.
•The contrast material may taste unpleasant.
Sialography
sialodochitis
* Contraindication:
Sialography is contraindicated in acute infection of salivary gland. We use with
acute infection the ultrasound to demonstrate the abscess.
Salivary calculi is questionable

9. Biopsy: Removing tissue from a patient for histopathological examination.
Histopathology
Indications
1- Persistent oral ulcers.
2- Persistent red and white lesion
3- suspected neoplasm or any
unidentical tissue masses.
A- surgical biopsy
1-Excisional 2-Incisional
1- Excisional biopsy: is the removal of whole lesion.
- Can be performed when the lesion no larger than 1 cm
in diameter
- When it is removal doesn’t necessitate a major
surgical procedure

10. Indications:
If the lesion is too large for an excisional procedure.
Contraindications:
Incisional biopsy of parotid gland tumors (plemorphic adenoma)
is contraindicated but may be examined microscopically only after
excision with a margin of surrounding normal tissue.
2- Incisional biopsy:
Removal only part of lesion which also include normal
tissue margin.
Punch biopsy

11. The biopsy must be:
- choose from the most suspected area
- Avoid ulcers slough or necrotic area
- Give regional or local anesthesia far from the
biopsy
- Include normal tissue margin.
- Specimen should preferably at least 1x 0.6
cm x 3mm deep.
- Specimen edges should be vertical not
beveled

12. Indication:
 Diagnosis of swelling in lymph node
 Metastatic carcinoma, Hodgkin’s and non Hodgkin’s
Lymphoma
 Tumors of parotid gland.
The fine needle is inserted into the lesion and cell aspirated and smeared on a slide.
The cells can be fixed, stained and examined within minutes.
B- Fine needle aspiration
Advantages
1- Avoid damage in vital structures in the neck and head
2- To prevent the spread of tumor cells
3- Less risk of delayed wound healing and infection
4- Rapid diagnosis and treatment
5- It is economy.

13. C- Thick needle/ Core biopsy.
This method useful for inaccessible tumors, e.g. in the pharynx.
But:
•it has risks of seeding some types of neoplasm into the tissues and
•damaging adjacent anatomical structures.
•It is less used in the head and neck now that FNA is more widely available.

14. D- Exfoliative cytology
It is examination of cells scraped from the surface of the lesion
Indication:-
• -Most useful for detecting virally- damaged cells, acantholytic
cells of pemphigus or candidal hyphae.
• -Used for patient who should be biopsied but for whom
surgical risk or some other factors prevent it.
• -For patients refuse biopsy.
Contraindication:-
• -In obvious malignancy.
• -In leukoplakia

15. Indication:
• Pemphigus and pemphigoid
• Suspected Lymphoma
• Undifferentiated Malignant neoplasm
• Autoimmune disease
Immunofluorescence &
Immunohistochemistry
Use of highly specific binding between antibody and
antigen to stain specific molecules within the tissue

16. Immunohistochemistry

17. Immunohistochemistry
Cytokeratins

18. 4- Microbiology:
1- Culture and antibiotic sensitivity testes
a) Detect un usual pathogens e.g: Actinomycosis in soft
tissue infection.
b) Antibiotic sensitivity for all infections, especially:
-Osteomyelitis and acute facial soft tissue infection.
-Throat infection.
-Exudates from sinus infections.
-Root canal infections.
-Skin, mucus membrane infection.
2- Smear for candida: for candidiasis.
3- Viral culture or antigen screen.

19. Indications:
 Diagnosis of Disease such as leukaemia, Myloma and leukopenia
which have oral manifastation.
 Diagnosis of other conditions such as some infections, sore tongue
and recurrent aphthae which are sometimes associted with
anaemia.
Hematology & Blood chemistry

20. Types of blood tests useful in oral
diagnosis
CBC: RBC (number–size) Hb And white cell count:
Anaemia, lenkaemias, infections
ESR (erythrosedimentation rate)
Rais in systemic inflammatory and autoimmune disease
Iron test
Angular cheilitis, painful atrophic glossitis, microcytic anemia
Folate level and vit. B12 level.
Recurrent aphthous, ulceration, recurrent candidosis and
atrophy of papillae of the tongue
Viral antibody titers e.g herpes simplex, varicella zoster, mumps virus
Syphilis serology: Syphilis

21. Types of blood tests useful in oral
diagnosis
Serum calcium and parathormone level
– A- increase the level of Ca++
Hyperparathyroidism, Malignent Metastasis to bone, Multiple
Myeloma, Hypovitaminosis, paget’s disease of bone.
– B- decrease the level of Ca++
Hypoparathyroidism, Vitamin D diffeciency (rickets,
osteomalacia decrease intestinal calcium absorption and renal
insufficiency and in cases of tetani
Serum phosphate po4
– A- increase the level of po4
Chronic renal disease, healing bone fracture, hypopara-
thyrodism, Hypervitaminosis D, increase of level of Growth
Hormon
– B- decrease the level of po4
Rickets disease and osteomalacia

22. Types of blood tests useful in oral
diagnosis
• Blood Glucose level
– A- Increase blood glucose level.
Diabetic Mellitus, cushinges diseases, in patient taking corticosteriod and
thiazid diuretic drug.
– B- decrease blood glucose level.
Insulin –secreting tumor, extensive liver disease, pituitary hypofunction,
addison’s disease Mal absorption of monosaccharides.
• Serum Bilirubine
Haemolytic anaemia, biliary obstruction, hepatitis, hepatic malignancy.
• Serum uric acid
Gout, renal failure, leukaemia lymphoma, thiazid diuretic.
• Serum Alkaline phosphate
High level in condition with increased bone turnover e.g paget’s disease,
hyperparathyroidism, hypophosphatasia.
• Serum creatinin
Increased in kidny disease, acromegaly and patient with large muscle mass.

23. OTHER TEST
URINE TEST
Diagnosis of diabetes, autoimmune conditions which damage the kidney
TEMPERATURE TEST
-if the bone or soft tissue infection are suspected
- It helps distinguish facial inflammatory odema from cellulitis
-Systemic effect of infection and the need for more aggressive treatment
BLEEDING TIME TEST
CLOTTING TEST
BLOOD PRESSURE
Hypertension
Hypotension