مدسن محاضرة 2

Oral diagnosis
and
Laboratory
Investigation
Dr. Sahar Hamdan

Oral Medicine Dr. Sahar Hamdan
Introduction:-
Over the past several decades, the need for oral health care professionals to understand
basic principles of medicine and diagnosis has grown exponentially. This is due, changing
characteristics of patients seeking oral health services. The population is aging, and an
increasing number of patients seeking oral health services are living with chronic illnesses, are
taking multiple medications, and have undergone surgical procedures (eg, cardiac surgery,
organ transplantation) that prolong life but have a profound effect on craniofacial health and
function, as well as on the provision of dental care.
Oral medicine is a specialty within dentistry that focuses on the diagnosis and
management of complex diagnostic and medical disorders affecting the mouth and jaws.
Clinicians with advanced training in this discipline manage oral mucosal disease, salivary gland
disorders, and facial pain syndromes and also provide dental care for patients with complicating
medical disease.
Patients consult all oral health care professionals for management of problems related to
orofacial structures, and the opportunity and the need to evaluate and assess patients’ overall
medical status become part of the responsibility of the dentist.
The process of diagnosis is divided into five parts:
1. Obtaining and recording the patient’s medical history
2. Examining the patient
3. Establishing a differential diagnosis
4. acquiring the additional information required to make a final diagnosis, such as relevant
laboratory and imaging studies and consultations from other clinicians
5. Formulating a plan of action, including oral health care modifications and necessary medical
referrals

Medical History
Obtaining a medical history is an information-gathering method for assessing a patient’s
health status that will facilitate the diagnostic process for the patient’s complaint. The medical
history comprises a systematic review of the patient’s chief or primary complaint, a detailed
history related to this complaint, information about past and present medical conditions, social
and family histories, and a review of symptoms by organ system. a medical history also
includes biographic and demographic data used to identify the patient. an appropriate
interpretation of the information collected through a medical history achieves several important
objectives; it affords an opportunity for
(1) Gathering the information necessary for establishing the diagnosis of the patient’s chief
complaint
(2) Monitoring known medical conditions
(3) Detecting underlying systemic conditions that the patient may or may not be aware of
(4) Providing a basis for determining whether dental treatment might affect the systemic health
of the patient
(5) Assessing the influence of the patient’s systemic health on patient’s oral health
(6) Providing a basis for determining necessary modifications to routine dental care
Preprinted self-administered health questionnaires are readily available, standardized,
and easy to administer and do not require significant “chair time.” They give the clinician a
starting point for a dialogue to conduct more in-depth medical queries.
all medical information obtained and recorded in an oral health care setting is considered
confidential and constitutes a legal document. Although it is appropriate for the patient to fill
out a history form in the waiting room, any discussion of the patient’s responses must take place
in a safeguarded setting. Furthermore, access to the written or electronic (if applicable) record
must be limited to office personnel who are directly responsible for the patient’s care.

Examination of patient:-
The examination of the patient represents the second stage of the evaluation and
assessment process. An established routine for the examination is mandatory.
A thorough and systematic inspection of the oral cavity and tissues minimizes the
possibility of overlooking previously undiscovered pathologies. The examination is most
conveniently carried out with the patient seated in a dental chair, with the head supported. When
dental charting is involved, having an assistant record the findings saves time and limits cross
contamination of the chart and pen. Before seating the patient, the clinician should pay attention
to the patient’s general appearance and gait and should note any physical deformities or
handicaps.
This includes a thorough inspection and, when appropriate, palpation, auscultation, and
percussion of the exposed surface structures of the head, neck, and face and a detailed
examination of the oral cavity, dentition and oropharynx.
laboratory studies and additional special examination of other organ systems may be
required for the evaluation of patients with orofacial pain, oral mucosal disease, or signs and
symptoms suggestive of salivary gland disorders or pathologies suggestive of a systemic
etiology. A less comprehensive but equally thorough inspection of the face and oral and
oropharyngeal mucosae should be carried out at each dental visit.
Each visit should be initiated by a deliberate inspection of the entire face and oral cavity
prior to the scheduled or emergency procedure. The importance of this approach in the early
detection of head and neck cancer and in promoting the image of the dentist as the responsible
clinician of the oral cavity cannot be overemphasized.
A male dentist should have a female assistant present in the case of a female patient.
Female dentists should have a male assistant present in the case of a male patient. Similar
precautions should be followed when it is necessary for a patient to remove tight clothing for
accurate measurement of blood pressure. A complete physical examination should not be
attempted when facilities are lacking or when custom excludes it.

The Examination procedure in dental office settings includes five areas:
(1) Registration of vital signs (respiratory rate, temperature, pain level, pulse, and blood
pressure);
(2) Examination of the head, neck, and oral cavity, including salivary glands,
temporomandibular joints, and head and neck lymph nodes;
(3) Examination of cranial nerve function;
(4) Special examination of other organ systems;
(5) Requisition of laboratory studies.
Clinical examination:-
 Extra oral:-
Clinical examination of the patient starts by looking at the patient as a whole before looking in
his mouth. Anemia, thyroid disease, long term corticosteroid treatment, parotid swelling and
significant cervical nodes enlargement are few condition that affect the facial appearance.
The parotid glands, TMJ (clicking, crepitus and deviation) , cervical and submandibular lymph
nodes and thyroid gland, maxilla and frontal bone for sinusitis should be palpated.
Lymphadenopathy is a common manifestation of infection but may also signify malignancy.
The clinician should also note the character (site, shape, size, surface texture and consistency) of
any enlargement.

 Intra Oral examination:- Examination of oral cavity can only be performed
adequately with good light, mirror and compressed air, if viscid saliva prevents
visualization of tissue and teeth.
Establishing the diagnosis
When establishing a diagnosis in the orofacial region, the oral health care professional
should establish a differential diagnosis based on the medical history and physical examination
and order the necessary laboratory tests, such as biopsies or imaging studies, required to reach
the final diagnosis only after a differential diagnosis has been determined. in other
circumstances, when the patient’s symptoms suggest the presence of a general medical disease
and the clinical data are more complex,
The diagnosis may be established using four steps:
(1) Reviewing the patient’s medical history, physical, radiographic, and laboratory findings;
(2) Listing those items that either clearly indicate an abnormality or that suggest the possibility
of a significant health problem requiring further evaluation;
(3) Grouping these items into primary versus secondary signs and symptoms, acute versus
chronic problems, and high versus low priority for treatment;
(4) Categorizing and labeling these grouped items according to a standardized system for the
classification of disease.

Experienced clinicians who have an extensive knowledge of human physiology, disease
etiology, and a broad knowledge of the relevant literature can usually rapidly establish a correct
diagnosis. Such “mental models” of disease syndromes also increase the efficiency with which
experienced clinicians gather and evaluate clinical data and focus supplemental questioning and
testing at all stages of the diagnostic process.
Because oral medicine is concerned with regional problems that may or may not be
modified by concurrent systemic disease, it is common for the list of diagnoses to include both
oral lesions and systemic problems of actual or potential significance in the etiology or
management of the oral lesion. Items in the medical history that do not relate to the current
problem and that are not of major health significance usually are not included in the diagnostic
summary.
For example, a diagnosis might read as follows:
1. Alveolar abscess, mandibular left first molar
2. Rampant generalized dental caries secondary to radiation-induced salivary hypofunction
3. Carcinoma of the tonsillar fossa, by history, excised and treated with 65 gy 2 years ago
4. Cirrhosis and prolonged prothrombin time, by history
5. Hyperglycemia; r/O (rule out) diabetes a definite diagnosis cannot always be made, despite a
careful review of all history, clinical, and laboratory data. in such cases, a descriptive term
(rather than a formal diagnosis) may be used for the patient’s symptoms or lesion, with the
added word “idiopathic,” “unexplained,” or (in the case of symptoms without apparent physical
abnormality) “functional” or “symptomatic.” The clinician must decide what terminology to use
in conversing with the patient and whether to clearly identify this diagnosis as “undetermined.”
irrespective of that decision, it is important to recognize the equivocal nature of the patient’s
problem and to schedule additional evaluation, by referral to another consultant, additional
testing, or placement of the patient on recall for follow-up studies.

The SOAP note
The four components of a problem—subjective, objective, assessment, and plan (SOAP)—are
referred to as the SOAP mnemonic for organizing progress notes or summarizing an outpatient
encounter.
The components of the SOAP mnemonic are as follows:
 S- or subjective: the patient’s complaint, symptoms, and medical history (a brief review)
 O- or Objective: the clinical examination, including a brief generalized examination,
and then a focused evaluation of the chief complaint or the area of the procedure to be
undertaken
 A- or assessment: the diagnosis (or differential diagnosis) for the specific problem
being addressed
 P- Or Plan: the treatment either recommended or performed
The SOAP note is a useful tool for organizing progress notes in the patient record for
routine office procedures and follow-up appointments. it is also quite useful in a hospital
record when a limited oral medicine consultation must be documented.
Laboratory investigation
A laboratory test is a medical procedure requested by a physician, physician’s assistant
or a nurse practitioner in which a sample (specimen) of blood, urine, body fluid or other tissue
in the body is checked for certain features. These tests are used as part of a routine medical
examination to identify possible changes in a person’s health before or after symptoms may
appear.
Laboratory tests are also helpful in providing the physician/practitioner with information
so that they can narrow down a possible diagnosis when a person already has
symptoms. Additionally, laboratory tests may be used to help plan a patient’s treatment,
evaluate the effectiveness of the treatment and monitor the course of the disease over
time. Multiple laboratory tests may be necessary in order to “rule out” various conditions or
disease states.

 Special investigations :
There are innumerable types of investigation are possible and it may be difficult to refrain from
asking for every conceivable investigation in the anxiety not to miss something unsuspected and
to avoid medico-legal complication. Special investigation should only be requested to answer
specific question about a possible diagnosis, not as a routine. Some investigations are highly
specific and sensitive for particular disease. But few investigations provide a specific diagnosis.
Few diseases such as mumps may be diagnosed on the basis of single test. Therefore usefulness
of each investigation must be borne in mind when interpreting the results.
1- Imaging
The most frequent informative imaging technique to the head and neck are radiography,
computerized tomography (CT), magnetic resonance imaging (MRI) and ultrasound. Their
advantages and disadvantages are listed below:-
Techniques Advantages Disadvantages
Conventional Radiography Simple, widely available, many common
lesion can be identified with a high degree
of accuracy
Panoramic radiograph can show
unsuspected lesion
Difficult to interpret in some areas of
the jaws because of complex anatomy
X-ray dose unavoidable
Little information about soft tissue
lesions
CT Sectional images of high clarity in any
plane without superimposition
Very useful where complex anatomy
hinders interpretation of plain radiographs
Expensive, unavailable
High x-ray dose than plain
radiographs
Radiopaque dental restoration cause
artifactual shadows which obscure
part of the image
Less information on soft tissue lesions
than MRI
MRI No X-ray dose
Produce clear tomograms without
superimposition
Good for soft tissue lesion
Expensive and limited availability
Does not image bone
Ultrasound No x-ray dose
Shows Soft tissue masses and cyst well
Overlying bone obscure soft tissue
lesions
Technetium scan Assessment of function of salivary gland Equipment not always available
Radiation dose

Plain radiography is widely available but the value of additional technique should be
understood even simple maneuvers such as introducing a gutta percha point or probe into a
sinus to trace its origin may provide critical information. Whenever the radiograph appears
unusual or beyond the experience of the clinician a radiologist should be consulted.

Requirement for useful radiographic information:-
 Always take bitewings when dental pain is suspected.
 When imaging bony swelling always take two views at right angles.
 Panoramic tomograms cannot provide high definition of bony lesion, only a cross-
section lesion In focal trough and if the bone is greatly expanded only a small portion
will be in the focus.
 Radiography of the soft tissue is occasionally usefull for the instance to detect foreign
body or calcification of lymph nodes.
2- Histopathology:-
Value and limitations:-
Removal of a biopsy specimen for histopathological examination is a mainstay of diagnosis for
disease of mucosa, soft tissue and bone. In the few condition in which a biopsy is not helpful. It
may be still valuable to exclude other causes
The possible reasons for failure in histological examination
 Specimens poorly fixed or damaged during removal.
 Specimens are unrepresentive of the lesion or too small.
 Plane histological section doesn’t include critical features.
 The condition doesn’t have diagnostic histological features ( aphthous ulcers).
 The histological features have several possible causes (granulomas).
 The histological features are difficult to interpret
 Inflammation may mask the correct diagnosis

Biopsy:-
Biopsy is the removal and examination of a part or the whole lesion, there are several types
of biopsy are:-
 Surgical biopsy (incisonal or excisional).
 Fine needle aspiration biopsy FNA.
 Thick needle/ core biopsy.
Essential biopsy principle:-
 Choose the most suspicious area.
 Avoid slough or necrotic areas.
 Give regional or local anesthesia not into the lesion.
 Normal tissue margin should be included.
 Specimen should be at least 1 X 0.6 cm by 2 mm in depth.
 Pass a suture through the specimen to control it and prevent it being swallowed or
aspirated by the suction.
 For large lesion several areas may need to be sampled.
 Include every fragment for histological examination.
 Label specimen bottle with patient name and clinical details.
 Suture and control bleeding.
 Warn the patient for possible soreness afterwards and give analgesic
 Check the findings are consistent with the clinical diagnosis and investigation.
 Discuss with pathologist or repeat biopsy if diagnosis is unclear or understood.

Surgical biopsy:-
Incisional biopsy (removal of part of a lesion) is used to determine the diagnosis before
the treatment while excisional biopsy (removal of the whole lesion as in mucocele) is used to
confirm the clinical diagnosis.
Occasionally general anesthesia is required in children or compromised patient. For the
gag a short acting benzodiazepine is usually effective. The request form should contain all the
clinical information used to reach the clinical diagnosis.

Frozen section:-
Frozen section technique allows a stained slide to be examined within 10 minutes of
taking the specimen, the tissue is sent fresh to laboratory to be quickly frozen, Preferably to
about -70 C.
Advantages and limitation of frozen section:-
 Can establish operation whether or not a tumor is malignant and whether excision needs
to be extended.
 Can confirm at operation that excision margins are free of tumor
 Appearances differ those in fixed material
 Definitive diagnosis sometimes impossible.
Frozen section can be justified if the rapidity of the result will make an immediate
difference to the operation in progress. If rapid diagnosis is required in other circumstances
other technique such as fine needle aspiration biopsy may be used.
Fine needle aspiration biopsy:-
FNA is often sufficient to distinguish benign from malignant, to intiate treatment and to
indicate a need for further investigation.
Principle and uses of fine needle aspiration biopsy:-
 A 21 gauge needle is inserted into the lesion and cells aspirated and smeared on a slide.
 Rapid and usually effective aid to the diagnosis of swelling in lymph node and parotid
tumors especially.
 Cells can be fixed stained and examined within minutes
 Valuable when surgical biopsy could spread tumor cells
 For deep lesion ultrasound or radiological guidance may be used to ensure that the
needle enters the lesion.
 No significant complication.
 Small size of the needle avoids damage to vital structures in the head and neck.
Disadvantages:-
 Experience required for interpretation.
 Small specimen may be unrepresentative.
 Definitive diagnosis not always possible.

Advantages and limitation of needle/core biopsy:-
 Needle up to 2mm diameter used to remove a core of tissue.
 Specimen processed as for surgical biopsy.
 Larger sample than FNA presrves tissue architecture in the specimen
 Definitive diagnosis more likely than with FNA
 Risk of seeding some types of neoplasm into the tissue
 Risk of damaging adjacent anatomical structures
 Useful for inaccessible tumors
 Less used in the head and neck now that FNA is more widely available
Exfoliative cytology:-
Exfoliative cytology is examination of cells scraped from the surface of a lesion or
occasionally of material in aspirate of a cyst.
Biopsy is always more reliable and can be so readily carried out in the mouth that its
mandatory when cancer and premalignancy is suspected. Exfoliative cytology samples only
surface cells and provide no information on deeper tissues.
Advantages :-
 Quick and easy.
 Local anesthesia not required
 Special techniques such as immunostaining can be applied
 Most useful for detecting virally damaged cells acantholytic cells of pemphigus or
candidal hyphae.
Disadvantages:-
 Unreliable for diagnosing cancer.
 Frequent false positive and false negatives result

Brush biopsy:-
This technique uses a round stiff bristle brush to collect cells from the surface and
subsurface layer of a lesion by vigorous abrasion.

Laboratory procedure:-
Although a clinician does not need to understand the details of laboratory procedure it is
necessary to understand the principles to enable the optimal result to be obtained.
Fixation:
In the absence of proper fixative its better to delay the biopsy and obtain the correct
solution. Specimens placed in alcohol, saline or other materials commonly available in dental
surgeries are frequently useless for diagnosis.
Essential points about specimen fixation:-
 Fixation is necessary to prevent autolysis and destruction of microscopic features of the
specimen
 The usual routine fixative is 10% formal saline
 Fixative must diffuse through the specimen
 Small surgical specimen fix overnight but large ones take 24 hours or longer
 The center of specimen may autolyse before being fixed but pathologist can incise them
to allow fixative to penetrate.
Some common stains used for microscopy:-
 Haematoxylin and eosin stain (H&E) :- it’s the most common routine histological stain.
In which :-
Eosin:-
- Cytoplasim
- Keratin
- Muscle cytoplasm
- Bone
- Collagen
Haematoxylin :-
- Nuclei
- Mucopolysacharide
- Reversal line in decalcified bone

 Periodic acid Schiff (PAS) stain:-
Most second common stain used to stain carbohydrate and mucinous substances pink,
its useful to identify salivary and other mucins, glycogen and candidal hyphae in sections.
Silver staining is also useful for identifying fungi in sections but gram staining is quicker and
more useful in smears.
Decalcified and ground section:-
Decalcification is a process of complete removal of calcium salt from the tissues like
bone and teeth and other calcified tissues following fixation.
Immunofluorescence:-
is a technique used for light microscopy with a fluorescence microscope and is used
primarily on microbiological samples. This technique uses the specificity of antibodies to their
antigen to target fluorescent dyes to specific biomolecule targets within a cell, and therefore
allows visualization of the distribution of the target molecule through the sample
Immunohistochemistry or IHC:-
refers to the process of detecting antigens (e.g., proteins) in cells of a tissue section by
exploiting the principle of antibodies binding specifically to antigens in biological tissues
Molecular biological tests:-
Molecular biological diagnostic test have revolutionized diagnosis particularly in
screening for and identification of genetic abnormalities and rapid identification of bacteria and
viruses. Some malignant neoplasms have characteristic genetic abnormalities, mostly
chromosomal translocations which can be detected by cytogenetic, polymerase chain reaction or
fluorescent in situ hybridization. Molecular techniques are also the method of choice for the
diagnosis of some lymphomas which cannot be accurately categorized by routine histological
methods.

Hematology , clinical chemistry and serology:-
Blood investigations are clearly essential for the diagnosis of disease such as
leukemia, myelomas or leucopenia’s which have oral manifestations or for defect of
haemostasis which can greatly affect management. Blood investigations are also helpful in the
diagnosis of other conditions such as infection, sore tongue and recurrent aphthous which are
sometimes associated with anemia.

Microbiology:
Despite the fact that the most common oral diseases are infective, it is surprisingly
rarely of practical diagnostic value in dentistry. Direct gram positive smear will quickly confirm
the diagnosis of thrush or acute ulcerative gingivitis, H&E stained smears can show the
distorted virally infected epithelial cells in herpetic infections more easily than microbiological
tests for the organisms themselves.
A key investigation is culture and sensitivity of pus organisms. Whenever pus is
obtained from a soft tissue or bone infection it should be sent for culture and determination of
antibiotic sensitivity of the causative microbes. Those of osteomylitis, cellulitis, acute parotitis,
systemic mycoses or other severe infections need to be identified if appropriate antimicrobial
treatment is to be given. Viral infection is rarely required for oral disease as many oral viral
infections are clinically typical and indicate the causative virus. A smear alone may show the
nuclear change of herpetic infection in epithelial cells from the margins of mucosal ulcers. A
more sensitive and almost as rapid result may be obtained by sending a swab for virus detection
using ELISA
Other clinical Tests:-
Several simple clinical test may be valuable in diagnosis of oral disease. Urine test
are valuable for the diagnosis of diabetes ( suggest repeated candidal or periodontal infection).
Autoimmune conditions which damage the kidneys for instances wegener’s
granulomatosis and for the detection of bence-Jones protein in myloma. Patient temperature
taking is noted whenever bone or soft tissue infection are suspected. It helps distinguish facial
inflammatory odema from cellulitis and indicate systemic inflammatory effect of infections and
need for more aggressive therapy Finally ensure that the patient notes include complete record
of the consultation and investigation results, this must be correctly dated legible limited to
relevant facts and include a clear compliant history.

مدسن محاضرة 2

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مدسن محاضرة 2