Biological examinations in odontostmatology
1-Introduction: Regularly, the dental surgeon will have to resort to laboratory analyses or additional examinations to better identify the patient’s problems. Well chosen and well interpreted, laboratory analyses often provide essential information for the diagnosis of oral diseases.
The use of these commonly used tests is of particular interest in dental medicine. Indeed, certain diseases are diagnosed only with the help of these tests.
2- Blood tests:
a/ Blood count: the blood count or blood formula count consists of determining the number of erythrocytes and leukocytes per microliter ( µl = 10-6 liters , previously cubic millimeter { mm3 }). It is also used to evaluate certain qualitative and morphological data.
*Component of the blood count:
– Erythrocyte count.
– White blood cell count and white blood cell formula.
– Platelets.
– Hemoglobin dosage.
– Hematocrit.
– Erythrocyte constants: VGM, CCMH, TGMH.
– Morphology of erythrocytes and leukocytes.
The blood count is useful for:
– Determine the systemic reaction to oral infections, for example in a case of LUDWIG’s angina.
– Confirm or rule out certain systemic diseases (infectious mononucleosis, primary herpes, cyclic neutropenia, polycythemia, acute leukemia, etc.) which may manifest in the oral cavity.
Erythrocyte count:
Red blood cells are anucleated cells, they mainly contain hemoglobin, and together with white blood cells and platelets constitute the three formed elements of blood.
Red blood cells are necessary for oxygen transport and tissue hemostasis. Their lifespan is 110±10 days.
- Main indications:
– preoperative assessment.
– diagnosis is followed by anemic syndrome whatever the etiology (asthenia, pallor, hemorrhage).
– suspicion of polycythemia (thalassemia syndrome, vaquez’s disease)
- Normal values: they vary according to age and sex;
Male: 4.5 to 5.9 *10°6 /mm³
Female: 4 to 5.4 *10°6 /mm³
Child: 3.8 to 4.5 *10°6 /mm³
Newborn: 4.4 to 6 *10°6 /mm³
- Pathological variations:
The increase is seen mainly in primary polycythemia or vaquez’s disease and in myeloproliferative syndromes affecting the erythrocyte line.
It is secondary to thalassemia minor, respiratory failure and in certain heart diseases (most often congenital). A false increase can be obtained by hemoconcentration.
The decrease is observed during hemolysis or significant hemorrhage, bone marrow aplasia, dyserythropoiesis, erythroblastopenia,
Folic acid and vitamin B12 deficiencies cause a decrease in the number of red blood cells. This may be due to hemodilution.
White blood cell count and leukocyte formula:
White blood cells are nucleated cells including polymorphonuclear cells (neutrophil, basophil, eosinophil), lymphocytes and monocytes.
White blood cells are involved in the fight against infectious agents and the immune response. Determining the percentage of each category of leukocyte constitutes the leukocyte formula.
- Main indications:
The white blood cell count and leukocyte formula are mainly motivated during:
– fever.
– infectious and inflammatory syndrome.
– malignant diseases
– hepatomegaly.
– splenomegaly.
– lymph nodes.
- normal values:
The number of white blood cells and the leukocyte formula vary according to age:
– Newborn: 10 – 25 * 10°3 / mm³
– 1 month: 5 – 15 * 10°3 / mm³
– 1 year: 4 – 12 * 10°3 / mm³
– Child and adult: 5 – 10 * 10°3 / mm³
Biological examinations in odontostmatology
- the leukocyte formula (%):
| Newborn | 4 year old child | Adult | |
| P neutrophils | 40 – 80 | 20 – 40 | 50 – 80 |
| Peosinophils | 1 – 4 | 1 – 4 | 1 – 4 |
| P basophils | 0 – 4 | 0 – 1 | 0 – 1 |
| Lymphocytes | 20 – 40 | 50 – 70 | 20 – 40 |
| Monocytes | 2 – 10 | 2 – 10 | 2 – 10 |
- pathological variations:
– Neutrophilia (generally >7,500/µl): it is increased in bacterial infections, inflammatory syndromes, cancers, certain metabolic diseases and MI.
– Neutropenia (<1,500/µl): this may be due to production disorders, excessive destruction, distribution disorders or drug intake (amidopyrine, sulfonamide, phenacitin).
– Eosinophilia (> 500 /µl): it indicates parasitosis, an allergic reaction, or a malignant hemopathy.
– Basophilia (> 200 /µl): it is encountered during chronic myeloid leukemia, primary polycythemia or hypothyroidism.
– lymphocytosis (> 4000 /µl): it is observed in many viral (infectious mononucleosis) and bacterial (whooping cough) diseases or malignant lymphoid haemopathy.
– lymphopenia (< 1000 /µl): it is found in immune deficiencies, HIV infection (AIDS).
– Monocytosis (> 1000 /µl): it is encountered in certain infectious diseases, certain inflammatory conditions, in HODGKIN’s disease, myeloma, myelomonocytic leukemia.
Platelets: Platelets or thrombocytes are fragments of plasma without a nucleus, platelets play a fundamental role in primary hemostasis.
- Main indications: it is prescribed mainly during:
– preoperative assessment.
– hemorrhagic syndrome.
– monitoring of heparin treatment.
– autoimmune diseases. – purpuras.
- Normal value: 150 – 400 * 10°3 / mm³
- Pathological variation:
-Thrombopenia: this is the drop in the number of platelets below
150 * 10°3 / mm³.
Two mechanisms must be distinguished:
-central thrombocytopenia: due to insufficient bone marrow production.
-peripheral thrombocytopenia: due to excess destruction.
-Thrombocytosis: this is the increase in the platelet count beyond 500*10°3/mm³
It can be reactive: postsplenoctemia or after massive hemorrhages, trauma, surgical intervention, during infectious diseases, cancers and during chronic iron deficiency.
It can also be primitive, from essential thrombocythemia or during other chronic myeloproliferative syndromes: chronic myeloid leukemia CML, Vaquez’s disease, myeloid splenomegaly.
Hemoglobin (Hb): Hemoglobin is the main constituent of red blood cells, it ensures the transport of oxygen from the lungs to the different tissues, and the transport of carbon dioxide from the tissues to the lungs.
- Main indications: The hemoglobin level is of interest in the diagnosis and monitoring of anemic syndromes regardless of the etiology with clinical signs such as; asthenia, pallor, hemorrhage.
- Normal values: they vary according to age and sex;
Men: 14 – 18 g/dl
Female: 12 – 16 g/dl
Child: 11 – 14 g/dl
Newborn: 14 – 20 g/dl
Biological examinations in odontostmatology
- Pathological variations: an increase in the hemoglobin level is observed in hemoconcentration (dehydration, burns) or in true polycythemia. Smoking and long stays at altitude increase the Hb concentration.
The decrease generally indicates anemia (iron deficiency, enzymopathy). The diagnosis of false anemia by hemodilution is made by taking into account the blood mass.
Hematocrit (Ht): This is the ratio of red blood cell volume to blood volume expressed as a percentage (%).
- Normal values: they vary according to age and sex;
Male: 40 – 54%
Women: 37 – 45%
Child: 33 – 44%
Newborn: 50 – 64%
- Pathological variations:
Increased Ht is seen in primary and secondary polycythemia as well as in hemoconcentration.
The decrease is observed during anemias of hypersplenism and during the increase of plasma volume (cirrhotic ascites, cardiac and renal insufficiency)
Mean corpuscular volume (MCV):
Constant calculated by the ratio:
hematocrit (Ht) / number of red blood cells
- Normal values: they vary according to age
– newborn: 110 ±10 µm³
– 3 months: 88 ±8 µm³
– 1 year: 78 ±8 µm³
– 3 – 6 years: 81 ± 8 µm³
– 10 – 12 years: 84 ±7 µm³
– adult: 90 ±7 µm³
- Pathological variations: the increase is a macrocytosis defined by a VGM >100 µm³.
It is encountered in BEIMER’s anemia, vitamin B12 and/or folate deficiency, alcoholism, and during certain treatments (antifolic, AZT (Retrovir©) in HIV+ subjects).
The decrease is a microcytosis (<80 µm³) observed during iron deficiency, during inflammatory syndromes and thalassemias.
Mean corpuscular hemoglobin content (MCHC):
It is obtained by the ratio:
Hb (g/l) / number of red blood cells (10°12 /L)
- Normal values: they vary according to age
– newborn: 33±4 pg
– 3 months: 29 ±5 pg
– 1 year: 27 ±4 pg
– 3 – 12 years: 27 ±3 pg
– adult: 30 ±2 pg
- pathological variations:
Mean corpuscular hemoglobin concentration (MCHC) varies in parallel with MCV, it is increased in macrocytic anemias and decreased in microcytic anemias. Mean corpuscular hemoglobin concentration (MCHC):
The CCMH is the concentration of Hb in the erythrocyte mass. It is calculated by the ratio:
Hb (g/l) * 100
Ht
- Normal values: 33 ± 2%
- Pathological variations:
There is no hyperchromia because the RBC saturation value in Hb is 35%.
CCMH is decreased in normo or microcytic hypochromic anemias (CCMH <30)
Reticulocytes:
Reticulocytes are the youngest red blood cells in circulating blood.
They contain the remains of messenger RNA. Their level is a reliable indicator of bone marrow production.
- Main indications:
Reticulocytes are required in anemic syndromes.
- normal values:
1 – 3% or 25 – 75 * 10 °3 / mm³
- pathological variations: when the reticulocyte count is:
> 120 * 10°3 / mm³, the anemia is said to be regenerative (hemorrhage and hemolysis)
Anemia is said to be non-regenerative when the number of reticulocytes is not high.
b/ hemostasis assessment:
- Exploration of primary hemostasis:
a) Bleeding time : this is a global test of primary hemostasis, carried out by measuring the time required to stop bleeding caused by incision. It explores platelets, vascular walls and certain plasma factors (Willebrand factors and fibrinogen)
* Duke’s Method: the oldest, incision at the level of the earlobe, in normal condition TS is 2 to 4 min. This method must be abandoned due to lack of sensitivity and lack of standardization.
* The Ivy Method: (Ivy incision) The most used, incision made at the level of the forearm, in the
Normally the TS is 4 to 8 min.
– An elongated TS can be explained by:
🡪recently taking certain medications (aspirin,
Phenylbutazone).
🡪a disease of primary hemostasis (thrombopathies, thrombocytopenia, Willebrand disease).
– A prolonged TS, with a decrease in the number of platelets in the blood, suggests THROMBOPENIA.
- A lying TS alone suggests THROMBOPATHY, Willebrand disease.
Biological examinations in Odontostmatology Biological examinations in Odontostmatology
It cannot in any case be considered as a screening test for the risk of hemorrhage but can be part of a diagnostic approach.
b) VON WILLEBRAND factor : VON WILLEBRAND disease is a hereditary condition, characterized by:
*a hemorrhagic syndrome of variable severity, mainly cutaneous and mucosal.
*a biological syndrome associating to varying degrees an increase in bleeding time, quantitative and/or qualitative abnormalities of the complex (factor VIIIc – WILLEBRAND factor) and an increased TCA, sometimes moderately, or even normally.
- Main indications:
-In cutaneous-mucosal hemorrhagic syndromes.
-Prolongation of bleeding time.
-Prolongation of the TCA with an isolated lowering of factor VIIIc.
- Exploration of coagulation:
a/ Coagulation factors:
Plasma coagulation factors are divided into:
– enzyme precursors (serine protease zymogens: factors II, VII, IX, X, XI, XII);
– cofactors: factors V and VIII;
– substrates: fibrinogen;
– factor VIII: transpeptidase zymogen.
Coagulation requires the intervention of several factors and takes place in three stages:
*fibrinoformation
*activation of prothrombin into thrombin.
*prothrombinase.
- Main indications: Separate dosage of each factor is performed in case of TP and/or TCA disturbance.
Intrinsic pathway factors:
| FACTORS | VALUES | PATHOLOGICAL VARIATIONS |
| Factor VIII c Anti-hemophilic A | 60 – 150% | *Decrease: Hemophilia Willebrand disease *Increase: Thromboembolic complications Coronary atherosclerosis Renal failure Diabetes |
| Factor IX c Anti-hemophilic B | 60% | Decrease: hemophilia bVitamin K deficiency Liver damage (liver cirrhosis) |
| Factor XI ROSENTHAL | 60 – 150% | Congenital deficiency <50 |
| Factor XII HAGEMEN | 60 – 150% | Congenital deficiency Heterozygous 20 – 60 |
Extrinsic pathway factors:
| Factors | Normal values |
| Factor II (prothrombin) | 70 – 120% |
| Factor V (proaccelerin) | 70 – 120% |
| Factor VII (proconvertin) | 70 – 120% |
| X Factor (Stuart) | 70 – 120% |
| Factor VII + X | 60 – 120% |
- Pathological variations:
-The isolated deficiency of one of these factors is most often congenital.
-The deficiency associated with factors II, V, VII, X is encountered in hepatic failure, cirrhosis, hepatitis, fibrinolysis and disseminated intravascular coagulation (DIC).
-The combined deficiency of factors II, VII, X and Ixc is encountered in treatment with anti-vitamin K (AVK), deficiency of intake or absorption of vitamin K, hemorrhagic disease of the newborn, retention jaundice and treatment with antibiotics.
b) Partial thromboplastin time + activator (PTT): The TCA is a global coagulation test which measures the coagulation time of a decalcified, deplateleted plasma, always in relation to a control plasma.
This test consists of activating the intrinsic pathway (IV, VII, VIII, XI) of coagulation by different substances: Kaolin (TCK = Kaolin Cephalin Time) .
- Main indications:
TCA is prescribed in the context of:
– a preoperative assessment.
– personal and/or family hemorrhagic manifestations.
– monitoring of heparin treatment.
- Normal values:
Average time: 35 seconds
- pathological variations: pathological threshold: lengthening of more than 9 seconds compared to the local control.
c) Quick time / prothrombin time (PT): PT is a global coagulation test that explores the factors of the extrinsic coagulation pathway: proconvertin (F.VII), proaccelerin (FV), stuart (FX), prothrombin (F.II), and fibrinogen.
- Main indications: TP is prescribed in the context of:
– a preoperative assessment
– an assessment motivated by personal and/or family hemorrhagic manifestations.
– monitoring of treatment with anti-vitamin K.
- Normal values: 80 – 100%
- Pathological variations: For patients taking anti-vitamin K: the TP is evaluated in INR (international normalized ratio):
d) INR = pathological TP / control TP x
normal value: 1
Therapeutic window: TP is 30 – 45%, INR is 2 -3
e) Factors XII fibrin stabilizing factor (FSF):
- Normal values:
60 – 150%
- Pathological variations:
Decrease in factor VII is observed in congenital deficiencies; the clinical picture is dominated by hemorrhagic syndrome.
- Exploration of fibrino-formation:
a/Fibrinogen: It is an essential protein for coagulation and hemostasis; under the action of thrombin it is transformed into fibrin. Fibrinogen is also an important marker of the inflammatory reaction.
- Main indications:
Fibrinogen is prescribed in the context of:
– defibrination syndrome (DIC);
– an inflammatory syndrome;
-monitoring of fibrinolytic treatment (urokinase, etc.)
-liver failure.
- Normal values:
2 – 4 g/l
- Pathological variations:
Hyperfibrinogenia is encountered in inflammatory conditions, acute rheumatic fever (ARF), pneumonia, lipoid nephrosis and in some obstructive jaundice.
Hypofibinogenic < 2g/l may indicate a synthesis defect (congenital hypofibrinogenemia, severe liver failure), fibrinolysis or disseminated intravascular coagulation (DIC).
b/Thrombin time: This is the fundamental test for exploring fibrinoformation. It consists of measuring the plasma coagulation time in the presence of a standard quantity of thrombin.
- Main indications:
– abnormality of fibrinoformation.
– unexplained prolongation of the TCA.
– in the context of the search for circulating anticoagulant.
- Normal values: ≤ 22 seconds.
- Pathological variations:
-A prolongation of the TT reveals dysfibrinogenemia, afibrinogenemia, or congenital hypofibrinogenemia, the presence of antithrombin: heparin, degradation product of fibrin and fibrinogen (PDF), monoclonal Ig (myeloma).
-TT is also prolonged in inflammatory syndromes, severe hepatitis, cirrhosis, fibrinolysis and disseminated intravascular coagulation (DIC)
c/Reptilase time:
The reptilase time is a thrombin time that is not sensitive to heparin.
- Main indications:
In case of prolonged thrombin time, to eliminate the presence of heparin (heparin therapy or sample accidentally contaminated by heparin).
- Normal values: ≤ 22 seconds.
- Pathological variations:
The circumstances of prolongation of reptilase time are the same as in prolongation of thrombin time except that it is not prolonged in the presence of heparin.
The main indications in pathologies and oral surgery:
In daily practice, it is essential to detect patients likely to have haemostasis disorders before any surgical intervention.
To do this, it is essential that a precise interview be carried out, that a careful clinical examination be carried out and that the patient be prescribed certain laboratory tests.
The medical questionnaire will be intended to:
* look for general personal and family history (hemophilia A or B, thrombocytopenia, etc.)
look for medical history: liver diseases, genetic disorders, chronic inflammatory diseases, leukemia and other forms of malignant diseases Being or having been treated with chemotherapy.
* look for medications that may interfere with coagulation: anticoagulants (heparin and antivitamin K), acetylsalicylic acid-based medications, antibiotics, etc.
- look for oral manifestations suggesting hemostasis and/or coagulation problems:
In general, the presence of mucocutaneous purpura suggests a platelet abnormality: hematoma and hemarthrosis suggest a coagulopathy.
Platelet abnormalities (quantitative and qualitative) and von Willebrand disease are manifested in the oral cavity by the presence of petechiae (numerous, multifocal and not blanching on pressure) located mainly on the palate; ecchymoses, gingival bleeding. spontaneous or occurring after brushing or microtrauma or hemorrhages following dental extraction or tonsillectomy.
Plasma abnormalities (hemophilia, deficiency of other factors) result in induced hemorrhages (tooth extraction, trauma). In all these situations, a hemostasis assessment must be carried out.
Erythrocyte groups “grouping”:
ABO Group:
- definition:
The antigens A and B determined by heredity define the blood groups called A, B, AB, O. Each subject has in his plasma so-called natural antibodies turned against the antigens that he does not
do not have.
Biological examinations in odontostmatology
- subject grouping:
A blood sample is taken on a heparinized tube.
The group is determined by two tests:
-Beth-vincent: highlighting of antigens carried by red blood cells in the presence of test sera of known specificity.
– the Simonin test: it must be combined with the previous one: detection of plasma anti-A and anti-B antibodies in the presence of red blood cells of known ABO group tests.
In both cases, the antigen-antibody reaction causes hemagglutination.
| The groups | Red blood cells and their antigens | Natural antibodies in their plasma |
| In group A | GR carrying Antigen A | Anti-B antibodies |
| In group B | GR carrying Antigen B | Anti-A antibodies |
| In group AB | GR carrying A and B | No antibodies |
| In group O (zero) | No antigen | Anti-A and anti-B antibodies |
-RHESUS group:
- Definition:
It is a system of 3 antigens, the most important of which is the D antigen. 80% of subjects carry a D antigen and are said to be Rhesus + (Rh+), while subjects who do not have the D antigen are said to be Rh-.
-an Rh+ subject can receive Rh- blood without incident.
– the transfusion of Rh+ blood to an Rh- subject leads to the production of antibodies called anti-Rh+ immune antibodies, any new transfusion of Rh+ blood will be followed in the subject by a hemolytic accident.
– other groups: There are many other antigenic systems defining the Kell, Duffy, Lutheran, Lewis groups, etc.
- Directions:
- Before any transfusion, it is necessary to carry out a search for antibodies directed against these antigens; this is the search for irregular agglutinins (anti-erythrocyte antibodies)
– children under 15 years of age, any woman of childbearing age, patients at risk of polytransfusion must receive phenotyped blood (respect for Rhesus system and Kell system antigens)
3-Exploration of the inflammatory state:
a/ Erythrocyte sedimentation rate (ESR): The erythrocyte sedimentation rate is the measurement of the fall in red blood cells in millimeters per hour in a blood sample taken with an anticoagulant.
It is a non-specific measure of inflammation, its increase reflects an inflammatory state, frequently used as a medical orientation test.
- Main indications:
VS is a commonly used test in:
-screening for infectious diseases;
-screening for inflammatory syndromes;
-neoplastic syndromes;
-WALDENSTROM’s disease;
-myelomas;
-systemic diseases;
-HORTAN’s disease (only emergency, helping with diagnosis).
- Normal values:
first hours:
man: 3 to 15 mm
female: 7 to 20 mm
- Physiological variations:
– the VS is greater in children than in the elderly.
– in women during the menstrual cycle.
– during pregnancy (the ESR increases from the 2nd week to return to normal approximately 1 month after delivery).
– when taking oral contraceptives and anticoagulants.
- Pathological variations: ESR is increased in:
*Infectious diseases (Tuberculosis, Hepatitis).
*Inflammatory joint diseases (RAA, Arthritis-Hematoid Arthritis).
* autoimmune pathology (Behçet’s disease).
* Necrotic processes (acute myocardial infarction, lymphoma, colon and breast cancer).
*during significant disturbances of serum proteins (nephrotic syndrome with azotemia, viral hepatitis, cirrhosis)
*during hypothyroidism and hyperthyroidism.
*during arsenious poisoning and lead poisoning.
-the decrease in ESR is rarer except during polycythemia and sickle cell disease.
b/ CRP (C-Reactive Protein): CRP is a protein synthesized by the liver, appearing in the blood upon the introduction of an antigen (element recognized as foreign).
It reflects acute inflammation, it rises very quickly during inflammatory processes.
- normal values:
< 6 mg /l.
- Pathological variations: It increases during:
* Bacterial infections (does not increase if the infection is viral);
* Myocardial infarction (does not increase in angina pectoris);
* Some cancers;
* Trauma, burns;
* Inflammatory diseases (arthritis, acute rheumatic fever).
4-Phospho-calcium balance :
a/Calcium: The normal level of calcium in plasma is 9.2 to 11 mg/100ml
*hypocalcemia can be found in osteomalacia (vitamin D deficiency), primary hypoparathyroidism.
*hypercalcemia can be found in hyperparathyroidism, in osteolytic bone metastases (releasing calcium), sarcoidosis.
b/Phosphorus:
- Normal values: 0.8 – 1.35 mmol/l in adults.
1.6-2.2 mmol/l in children under 2 years old.
- Pathological values:
– Hypoparathyroidism (Enamel hypoplasia, Atrophy of dental roots, Exostoses – Hypoparathyroidism (Enamel hypoplasia, Atrophy of dental roots, Mandibular exostoses, Thickening of bone trabeculae) – Hypervitaminosis D (increases p absorption) – Acromegaly – Gigantism – Leukemia – Renal failure
-Hyperparathyroidism and Recklinghausen’s disease – Rickets – Osteomalacia.
c/Serum alkaline phosphatase:
Enzymes contained in many tissues of the body, notably the liver and bones.
- Normal values: ˂ to 7 units (Bodansky)
- Physiological variations: an increase in the phosphorus level is noted during pregnancy or growth in children.
- Pathological variations: their elevation is encountered in many pathological processes:
*bone: rickets, osteomalacia, Paget’s disease, cancer metastasis.
*hepatic: cirrhosis, hepatitis, obstruction of the bile ducts…
*certain cancers neither liver nor bone…
– a decrease in alkaline phosphatase can be encountered in pathologies such as: hypothyroidism, scurvy, severe anemia, severe liver failure or even congenital hypophosphatasemia.
Biological examinations in odontostmatology
The main indications in oral pathologies and surgery:
-Calcium and phosphorus and serum alkaline phosphatase should be measured in the presence of lesions suggestive of Paget’s disease, fibrous dysplasia, hyperparathyroidism, osteoporosis,
multiple myeloma, osteosarcoma, metastatic tumor located in the jaws, etc.
-When a histopathologic report describes a giant cell lesion, serum calcium, serum phosphate (phosphoremia), and serum alkaline phosphatase should be measured to determine whether it is a giant cell granuloma or hyperparathyroidism.
– Spontaneous fractures.
| calcium | phosphorus | Alkaline phosphatase | |
| Normal values | 2.3 – 2.7 mmol/l | 0.7 – 1.5 mmol/l | |
| Rickets | N | decreased | increased (20-40 times) |
| Osteomalacia | decreased | decreased | N |
| Primary hyperparathyroidism | increase | decreased | Augmented (2-50 times) |
| Paget’s disease | N | N or increased | increase |
| Bone metastases | N or increased | N or increased | N or slightly increased |
| Multiple myeloma | increase | N | N or slightly increased |
5_ Bacteriological examination:
microbiological examination is recognized as essential in certain situations for:
*Identify bacteria associated with a pathology.
*To make the differential diagnosis between bacterial and viral infections.
*Indicate when conventional treatment does not provide an acceptable clinical response, in the presence of atypical symptoms without rational explanation, or in the presence of a risk factor.
*the sample is taken:
-by puncture in front of a suppurative collection.
-by swabbing in front of a fistula, an incision plane, surface lesions, alveolitis, superinfected traumatic lesions.
Biological examinations in odontostmatology
Dark-field microscope study: This method allows a limited bacterial diagnosis directly
on the dentist’s chair. It does not require fixation or Gram staining and is therefore quick and easy to implement. However, only morphotypes can be determined, i.e. the shape and
the mobility of a bacterium. The determination of these criteria allows limited conclusions to be drawn on the pathogenic power of microorganisms…
Bacterial culture:
*Culture consists of developing micro-organisms, it is carried out in small sterile cups called “petri dishes”, in which a culture medium is placed, agar gel for example.
*The advantage of culture is that it allows the performance of an antibiogram, the test which determines to which antibiotics a certain marker germ is sensitive or – always more important – resistant.
When sending a sample to the laboratory for bacterial culture and antibiogram, the presumed clinical diagnosis must be indicated so that the samples can be inoculated on the appropriate media. In addition, if the patient has been treated with antibiotics, the laboratory must be informed and the name of the medications indicated.
6-Mycological examinations:
The diagnosis is based on a specific mycological examination with the detection of the fungus and the recognition of the species. It requires a mycological sample.
- Sampling methods
In the oral cavity, a swab of the lesions is most often sufficient. Two swabs are necessary: one allows a smear for direct examination, the other is cultured on Sabouraud medium.
A suspicion of deep mycosis requires a biopsy of the lesions; half of the sample is not fixed for mycological analysis and the other half is fixed for anatomopathological study.
- Direct examination
The samples are examined under a microscope in the fresh state between slide and coverslip on smears stained with Gram or Gridley in 10% potash.
-Candida appears in the form of yeasts, small isolated cells of 2 to 4 μm, oval, budding, with thin walls, more or less accompanied by mycelial filaments.
- Culture
The products are inoculated on two tubed culture media: Sabouraud glucose-agar medium enriched with chloramphenicol, which eliminates bacterial contaminants, and Sabouraud glucose-agar medium enriched with actidione, which inhibits or delays the development of saprophytic yeasts on the skin.
Yeast isolation takes 24 to 48 hours.
- Identification:
It is done by the blastesis test or yeast filamentation test.
Culture in potato-carrot-bile (PCB) medium is specific for Candida albicans.
- Interpretation of results
The diagnosis of oral mycosis is based on the comparison of clinical and paraclinical data. It is necessary to remain critical of the results of cultures due to the saprophytic presence of Candida on the oral mucosa.
Quantification of colonies on the culture can help in the therapeutic decision. Below 30 colonies, the presence of Candida can be considered as “normal” in the saprophytic state of the oral cavity. Above 30, it is agreed to recognize an oral mycosis that must be treated. Some results mention “numerous colonies”, which corresponds to a count of more than 100 colonies.
The main indications in oral pathologies and surgery:
These tests are indicated in cases of dry mouth, erythematous mucosa on acrylic resin prosthesis, burning sensation, dysphagia, whitish deposits which are eliminated with a compress and in populations at risk (HIV, diabetes, immunosuppressants, corticosteroids, elderly subjects, etc.)
7-Anatomopathological examination:
The biopsy:
- Definition: consists of removing a fragment of living tissue by surgical means for the purpose of carrying out a histological, biochemical, microbiological or immunological examination.
- Main indications:
* Establish or confirm the diagnosis of a suspicious lesion:
The biopsy allows the diagnosis to be made or determine whether the lesion is benign or malignant.
Any red lesion, a priori suspicious of erythroplakia or carcinoma in situ, must be biopsied. Any isolated white lesion that has recently appeared on a healthy mucosa, any unifocal white lesion or a multifocal one known in the context of lichen planus or chronic candidiasis, or any essential leukokeratosis must be biopsied if it changes (vegetative appearance, fissuring or ulceration, induration of the base).
* Specify and confirm the nature and specific characteristics of a malignant lesion:
Only the need for histological confirmation authorizes the initiation of treatment.
In addition to the histological classification of the tumor, the biopsy can allow us to know its evolution and to modulate the therapy accordingly. Depending on the histological nature, it is possible to assess the tumor’s radiosensitivity or chemosensitivity. The treatment will be definitively codified, or even corrected, as soon as the result of the sample is obtained.
In other situations, however, clinical examination alone does not allow a precise diagnosis to be made: it is then the anatomopathological examination which allows this to be done.
*Propose a diagnosis when the clinical picture is uncertain:
Clinical examination alone does not allow us to suggest several probable diagnoses of non-specific chronic ulceration.
*Make a diagnosis of infectious pathology:
The biopsy also allows the diagnosis of tuberculosis, syphilis, herpes.
* Systematic performance: Biopsy is performed systematically for pathologies related to dermatoses and for systematic diseases. These may be vesicular, bullous or other diseases; biopsy of lichen planus, pemphigus is necessary.
Biological examinations in odontostmatology
Lower labial accessory salivary glands are taken to look for:
- The etiological diagnosis of dry syndrome (GOUGEROT-SJOGREN syndrome);
- identify certain systematic pathologies (sarcoidosis, amyloidosis, scleroderma, rheumatoid arthritis, lupus, etc.).
- Contraindications
* absolute contraindications:
There are a number of risks that contraindicate taking a sample:
– risk of malignant degeneration, which is caused by the trauma represented by the act itself.
– serious hemorrhagic risk (e.g. angioma)
* relative contraindications:
As with any surgical procedure, biopsy may be contraindicated in the event of a risk of infection.
- Operating protocol:
1/Instrumentation:
– scalpel biopsy:
The sample is detached in depth using a scalpel, the part is grasped with soft-jawed forceps
– punch biopsy:
The punch biopsy is performed using an instrument with a cylindrical blade which is placed vertically on the area to be biopsied, a back and forth movement both in rotation and in vertical pressure allows a “core” to be individualized.
The instrument is then removed and the fragment held by the jaws of the forceps is released in depth by section of its pedicle. It is immediately fixed.
Biological examinations in odontostmatology
2/Disinfection and anesthesia:
The surgical site is washed with a compress soaked in serum. Then a disinfectant solution is applied: Betadine.
Infiltration anesthesia is performed at a distance from the healthy tissue lesion, because the pressure exerted by the anesthetic solution can modify the cellular arrangement.
– crown injection around the lesion.
– triangular injection by gradual withdrawal of the needle.
Biological examinations in odontostmatology
3/incisional biopsy:
Incisional biopsy involves removing a small fragment of the lesion in order to confirm or rule out the diagnosis or provide additional details.
4/excisional biopsy:
Excisional biopsy involves removing the entire benign tumor. When the lesion is small and there is suspicion of malignancy, the lesion will be removed with a sufficient margin.
5/Sampling direction:
In all cases, the cutting plane must be perpendicular to the surface of the mucosa, therefore vertical if this surface is placed horizontally.
In some cases, the vertical cutting plane must be oriented in a particular horizontal direction (e.g. perpendicular to the lesion boundary).
The sampled part is immersed in a fixing liquid “FORMOL”
– Sample routing:
The bottle containing the surgical specimen is labeled with the name and date of collection.
Each biopsy must be accompanied by an information sheet including:
*the patient’s name, first name, date of birth;
*any medical history of the patient;
*clinical information specifying the exact location of the sample and the size of the lesion.
* description of the macroscopic appearance of the lesion:
-nature of the sample (mucosa, bone tissue),
-inflammatory signs, hemorrhages, necrosis, ulceration….
-consistency (hard, soft, fibrous, etc.)
-description of the base (pedicle, sessile, infiltrate, fixed, mobile, etc.)
A clinically suggested diagnosis is proposed on the examination request.
- Salivary gland biopsy:
The biopsy of the accessory salivary glands is a simple procedure which consists of an incision of a few millimeters of the lower lip to obtain several glandular lobules.
This examination is easily used in routine practice because of its safety (relentless pain, few secondary incidents, lip hematoma or regressive localized anesthesia) and the accessibility of the glands.
| Systemic diseases | GOUGEROT–SJORGEN syndrome |
| Specific granulomatous inflammations | Sarcoidosis |
| Specific Deposit Diseases | Amyloidosis |
| Tumor pathology | non-Hodgkin’s malignant lymphoma |
| Other pathologies | Hyperlipoproteinemia HIV viral infection Hepatitis C Graft versus host disease |
After local anesthesia, the incision is made on the latero-internal surface of the lower lip, held by forceps. The mucosa is incised superficially, over 1 cm in length, without reaching the orbicularis muscle or the coronary artery. A few lobules are delicately removed with claw forceps to be placed directly in the fixative.
- Cytological examination:
* Exgoliative cytology:
This non-aggressive method is easy to perform. It gives rapid results, comparable in every way to those obtained in gynecology on cervical-vaginal smears.
– Indications:
The indications in dentistry are extremely limited:
-viral infections (demonstration of Unna ballooning cells which characterize herpes and shingles infections);
– bullous diseases (observation of acantholytic cells or Tsanck cells of pemphigus).
Note: In the oral mucosa, superficial keratinization may result in many (false negatives). A smear is not a good way to screen for squamous cell carcinomas.
*minimally invasive brush biopsy: this procedure has been adapted to the situation of sampling from the oral cavity. It is possible to obtain superficial desquamated cells or, using a special brush, cells located in the middle and deep layers of the epithelium, spread them on a glass slide and send them for cytopathological examination.
Biological examinations in odontostmatology
8/Serology:
* Sampling: 5 ml of blood collected without anticoagulant, two samples are taken, the first is taken at the onset of clinical manifestations (early sampling), the second is taken 2 to 3 weeks later (late sampling), and this in order to detect seroconversion or a significant increase in antibodies, which can confirm a recent infection by the infectious agent in question.
* Turnaround time The turnaround time for viral serology tests varies from one to three weeks for the less frequent ones that are performed in rare specialized laboratories. Some tests can be returned in one to two days (e.g. HIV).
*Hepatitis B virus (HBV):
Indication
-Diagnosis of viral hepatitis.
– people on hemodialysis.
Result: Several markers are considered, and their presence varies according to the stage of the disease.
| stadium | Ag HBs | Ag Hbe | Ac Anti-HBs | Ac Anti-HBc | Ac Anti-HBe |
| *Hepatitis – acute onset – condition – healing Chronic hepatitis Healthy carrier vaccination | +++/–++- | ++-++/– | –+/—+ | -+++++- | –+-+/– |
*Hepatitis C virus (HCV):
Indication:
-Diagnosis of viral hepatitis.
-control in at-risk populations: immunocompromised, polytransfused, hemodialyzed, transplanted, etc.
Results: The appearance of Acanti-HCV after a first negative test confirms the diagnosis of acute hepatitis. (Other methods in molecular biology can allow an early diagnosis: PCR genomic amplification and viral quantification, etc.)
*Hepatitis D virus (delta):
The infectious agent of hepatitis D is a viral agent called Delta Ag.
It is a defective virus that can only replicate in hepatocytes in the presence of a hepatitis B virus.
Main indications:
– episode of acute hepatitis in chronic carriers of hepatitis B (superinfection D).
-chronic hepatitis B (BD co-infection).
*Hepatitis E virus:
HEV is a virus of the calcivirus family.
The infection is relatively important in developing countries. It affects adults and transmission is oro-fecal. The most serious aspect is observed in pregnant women. Especially in the third trimester: significant jaundice and sometimes mortality.
Indication:
-Significant jaundice in pregnant women.
-The diagnosis is based on serology and the increase in aminotransferases (acute phase).
*Acquired immunodeficiency virus (HIV):
Indication:
-suspected HIV infection.
-assessment of contamination by infected blood.
-research in the newborn of an HIV mother.
Several methods are used, often in a complementary manner:
-ELISA (3rd generation): two methods are to be used: if + or if discordance, do western blot.
-western blot: + if presence of Ac directed against envelope proteins and at least one Ac directed against an internal protein.
- Epstein-Barr virus (EBV):
Epstein-Barr virus is a DNA virus of the Herpesviridae family. It infects B lymphocytes and causes infectious mononucleosis (IM).
Indication:
– suspicion of an MNI.
-Burkitt’s lymphoma.
-undifferentiated nasopharyngeal cancer.
- Mumps virus:
Mumps is a contagious infection, caused by a paramyxovirus, most often benign, which can cause testicular damage.
- Viral load/viral quantification:
Viral load or viral quantification are new methods allowing the titration of infectious virions or incomplete (non-infectious) virions and soluble or antibody-complexed viral proteins, which are present in the body of infected subjects.
Main indications:
-determination of the prognosis during viral infections by HIV and HCV viruses.
-therapeutic monitoring of these same infections.
Levy:
5 ml of blood collected without anticoagulant or in a citrated tube, and rapid delivery to the laboratory .
Measuring the viral load thus makes it possible to determine the prognosis of serious viral diseases (AIDS, hepatitis C), to choose the time of treatment and to judge its effectiveness.
In order to understand the techniques used for viral quantification, here are some reminders of the principles.
* Quantitative cellular viremia: measures the number of infected lymphocytes per million circulating mononuclear cells.
* Quantitative plasma viremia: measures the number of virions capable of infecting target cells per ml of plasma.
* PCR-RNA: measures the number of viral RNA bodies per ml of plasma.
*PCR-DNA: quantification of proviral DNA in infectious and non-infectious cells.
Viral RNA: refers to the number of infectious virions and defective virions.
p24/p25 antigenemia: measures soluble viral proteins by an ELISA technique.
- CD4 and CD8 titration:
Pathological variations:
In HIV infections, the CD4 lymphocyte count is an essential prognostic indicator for the occurrence of an opportunistic infection, and therefore of AIDS. For CD4 lymphocyte values above 600/mm, there are no short-term threats; for values between 300 and 600 CD4/mm, the risks are very significant.
- Tuberculosis: Tuberculin IDR.
- Syphilis:
VDRL: non-specific and reproducible test.
TPHA: specific test for treponematoses.
The fluorescent Treponema antibody absorption test (FTA-abs).
Nelson’s test (treponema immobilization test: TIT).
Interpretation:
Both tests: negative : no syphilis or very recent contamination (˂3 weeks, there are no antibodies yet).
Both tests: positive:
Primary stage syphilis
Secondary syphilis
Tertiary stage syphilis.
VDRL positive and TPHA negative: the VDRL reaction is falsely positive, perhaps linked to another pathology.
VDRL negative and TPHA positive: old syphilis (serological scar) or on the contrary very recent syphilis for which the second type of antibody has not yet appeared.
9-biochemical tests:
- Carbohydrate metabolism:
-Fasting blood sugar :
Normal values are between 0.65 and 1.10g/l according to the WHO.
-Postprandial blood sugar :
2 hours after the start or ½ after the end of the meal, it must be less than 2g/l.
-Induced oral hyperglycemia:
Early detection of diabetes. Assess carbohydrate tolerance after oral glucose load: 75g in adults; 1.75g/kg of weight in children; The glucose level should not exceed 120mg/100ml after 2 hours.
– Glycated hemoglobin (Hb1 Ac) = glycosylated:
Provides information on glucose balance during the previous 120 days; the normal value is < 6%. These last 2 tests are used in known diabetic subjects.
-HbA1c less than 7%: good control (green zone)
– HbA1c between 7 and 8%: imperfect control (orange zone)
– HbA1c greater than 8%: poor control (red zone)
Some benchmarks giving the equivalence between HbA1c and average blood sugar:
– 6% is equivalent to 1.2 g/l
– 7% is equivalent to 1.5 g/l
– 8% is equivalent to 1.8 g/l
– An increase of 1% is equivalent to + 0.3 g/l.
– Glycosuria:
Normal 24-hour glycosuria should be zero or less than 1g easily detected by strips: N-Labstix, Clinistix, N-Multistix
- Exploration of liver function:
* Serum transaminases: ASAT(GOT), ALAT(GPT): Highlight cytolysis especially of hepatic, smooth muscle (cardiac) or striated muscle origin.
Normal value ˂ 30 U/l.
- Exploration of renal function:
*Urinary clearance: This is the ratio between the urinary flow rate of a substance and its concentration in the blood.
Renal clearance of a substance is represented by the volume (in ml) of plasma that the kidney can completely rid of this substance in a minute.
Since creatinine is eliminated only by renal filtration, measuring its clearance makes it possible to assess the rate of renal filtration.
In men: 97-137 ml/min
In women: 88-138 ml/min
Creatinine clearance decreases physiologically by 6.5 ml/min beyond 30 years of age
Pathological values:
A value below 90 may be one of the first biological signs of incipient renal failure.
*Urea:
Produced by the liver, diffused throughout the body, eliminated mainly by the kidneys.
Normal values:
– Adult: 0.15-0.40g/l.
– Child: 0.25g/l.
– Infant: 0.15 g/l
10- in-office tests:
There are a number of clinical tests that the dentist can perform and interpret in his or her office. These include the epicutaneous test, or patch test, aspiration, toluidine blue (methylene) test, diascopy, or vitropression.
- Patch test:
Contact sensitivity test, is indicated to determine if a product can cause allergic stomatitis. This type of test is difficult to perform in the mouth. In someone who wears complete dentures.
- The Aspiration Test (exploratory puncture):
To determine the nature of the contents of large radiolucent lesions, an aspiration test can be used. If there is an abscess, a purulent liquid fills the syringe. If there is a cyst, a +/- yellowish liquid is removed from the cavity.
Blood is aspirated in cases of aneurysmal bone cyst or intraosseous hemangioma. In cases of traumatic cyst or central giant cell granuloma. Aspiration is also performed to collect pus from cellulitis, for bacterial culture and antibiogram.
- The toluidine blue test:
The toluidine blue test is based on the property of this substance to stain the nucleus of cells undergoing metaplasia, dysplasia or malignant changes.
The procedure involves first washing the target area with a 1% acetic acid solution. The solution should be left for at least one minute. Finally, rinse and rewash with acetic acid.
The area of tissue that retains a dark blue hue is where tissue changes are occurring.
Biological examinations in odontostmatology
Inflammatory cells can also take on the same staining as cancerous or precancerous cells.
glass pressure:
Vitropressure or diascopy is used to determine the vascular or non-vascular nature of a macular lesion. Either a glass or plastic slide is used …..
This test is easily performed on lesions located on the lips, oral mucosa, and tongue.
On pressure, vascular lesions (telangiectasias, varicose veins, hemangiomas) turn white, while other macules (petechiae, hematomas, nevi) do not change color. Depending on their histological nature and size, some hemangiomas turn white only partially.
- Conclusion :
In conclusion, to determine the value of the result of a test or laboratory analysis, it is necessary to refer to the normal data of the laboratory which carried out the analyses.
It is important to avoid jumping to conclusions too quickly when a test appears positive; it may be necessary to repeat the test or analyses before concluding.
Biological examinations in odontostmatology
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Dental X-rays reveal problems that are invisible to the naked eye.
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A diet low in sugar protects against cavities.