Pulp and Root Morphologies

Pulp and Root Morphologies

Root morphology

Successful root canal therapy requires a thorough knowledge of root and root canal morphology.

• Practitioners must be aware that the main root canals in a tooth may only provide access to the complexities of the root canal system, which must be fully cleaned of all microorganisms.

• Research has shown that the dental anatomy learned as a dental student may now be out of date.

• Knowledge of canal anatomy is essential in designing and executing access cavities that give straight line access to the main root canals.

Root canal system

The pulp chamber in the coronal part of a tooth consists of a single cavity with projections (pulp horns) into the cusps of the tooth . With age, there is a reduction in the size of the chamber due to the formation of secondary dentine, which can be either physiological or pathological in origin. Reparative or tertiary dentine may be formed as a response to pulpal irritation and is irregular and less uniform in structure.

The entrances (orifices) to the root canals are to be found on the floor of the pulp chamber, usually below the centre of the cusp tips. In cross-section, the canals are ovoid, having their greatest diameter at the orifice or just below it. In longitudinal section, the canals are broader bucco-lingually than in the mesiodistal plane. The canals taper towards the apex, following the external outline of the root. The narrowest part of the canal is to be found at the 'apical constriction', which then opens out as the apical foramen and exits to one side between 0.5 and 1.0 mm from the anatomical apex. Deposition of secondary cementum may place the apical foramen as much as 2.0 mm from the anatomical apex. It must be realized, however, that the concept of a 'single' root canal with a 'single' apical foramen is mistaken. The root canal may end in a delta of small canals, and during root canal treatment cleaning techniques should be employed to address this clinical situation.

Lateral and accessory canals

Lateral canals form channels of communication between the main body of the root canal and the periodontal ligament space. They arise anywhere along its length, at right angles to the main canal. The term 'accessory' is usually reserved for the small canals found in the apical few millimetres and forming the apical delta. Both lateral and accessory canals develop due to a break in 'Hertwig's epithelial root sheath' or, during development, the sheath grows around existing blood vessels. Their significance lies in their relatively high prevalence, Kasahara et al finding 60% of central incisors with accessory canals, and 45% with apical foramina distant from the actual tooth apex. Kramer found that the diameter of some lateral canals was often wider than the apical constriction. Lateral canals are impossible to instrument and can only be cleaned by effective irrigation with a suitable antimicrobial solution. Consequently, sealing such canals is only moderately successful.

Immune Deficiency and Oral Diseases

Immune Deficiency and Oral Diseases

           

Immunity

The protection against infectious disease conferred either by the immune response generated by immunization or previous infection or by other nonimmunologic factors.

·         Immune system consist of 2 components

1.     Non specific immunity

2.    Specific immunity

·         Cell mediated

·         Humoral

Immunodeficiency

Immunodeficiency disorders are a group of disorders in which part of the immune system is missing or defective. Therefore, the body's ability to fight infections is impaired. As a result, the person with an immunodeficiency disorder will have frequent infections that are generally more severe and last longer than usual.

Symptoms

The symptoms vary with the specific disorder.

Kaposi sarcoma

Signs

1.          Persistent, recurrent infections 
2.  Severe infection by microorganisms that do not usually cause severe infection

other signs include:

1.          Poor response to treatment for infections
2.          Delayed or incomplete recovery from illness
3.          Certain types of cancers (such as Kaposi's sarcoma or non-Hodgkin's lymphoma)
4.          Certain infections (including some forms of pneumonia or recurrent yeast infections)

Tests used to help diagnose an immunodeficiency disorder may include:

·         Complement levels in the blood, or other tests to measure substances released by the immune system

·         Immunoglobulin levels in the blood

·         Protein electrophoresis (blood or urine)

·         T (thymus derived) lymphocyte count

·         White blood cell count

Causes for primary immunodeficiencies

·         X linked agammaglobulinaemia

§  X linked hypogammaglobulinaemia

§  Immunoglobulin deficiency with increased IgM

§  Immunoglobulin heavy chain gene deletion

§  Kappa chain deficiency

§  Common variable immunodeficiency

§  IgA deficiency

§  Transient hypogammaglobulinaemia of infancy

§  Selective IgG subclass deficiency

·         Combined immunodeficiency

§  Severe combined immunodeficiency

§  Adenosine deaminase deficiency

§  Purine nucleoside deficiency

§  Major histocompatibility complex (MHC)ii deficiency

§  Reticular disgenesis

·         Well defined immunodeficiency syndromes

§  Wiskott-aldrich syndrome

§  Ataxia telengiectasia

·         Other syndromes associated with immunodeficiency

§  Bloom syndrome

§  Fanconi anaemia

§  Down’s syndrome

·         Multiple organ system abnormalities

§  Partial albinism

§  Short limb dwarfism

§  Cartilage hair hypoplasia

§  Chediak –Higashi syndrome

·         Hereditary metabolic defects

§  Transcobalamine 2 deficiency

§  Acrodermatitis enteropathica

§  Biotin dependent carboxilase deficiency

·         Hypercatabolism of immunoglobulin

§  Familial hypercatabolism of immunoglobulin

§  Intestinal lymphangiectasis

·         Other

§  Hyper IgE syndrome

§  Chronic mucocutaneous candidosis

§  Epstein-Barr virus associated immunodeficiency

·      

   Defects  in phagocytic function and neutropenia

§  Chronic granulomatous diseases

§  Neutrophil G6PD deficiency

§  Myeloperoxidase deficiency

§  Lecocyte adhesion defects

§  compliment deficiency

Secondary Immunodeficiency Conditions

·         Infections

§  HIV

§  Acute severe viral infections

·         Drug induced

§  Immunosuppressive drugs

§  Cytotoxic drugs

§  Radiotherapy

·         Myeloproliferative disordes

§  Myeloma

§  Leukaemias

§  Hodgkin’s and non Hodgkin’s lymphomas

·         Metabolic disorders

§  Malnutrition

§  Iron deficiency

§  Diabetes mellitus

·         Autoimmune diseases

·        

Chronic renal failure

miscellaneous

§  Neutropenia                            

§  Sarcoidosis

Primary immunodeficiency disorders and their related oral diseases

Severe combined immunodeficiency

This disease consists of profound deficiency of cell mediated and humoral immune systems. Oral conditions associated are candidal infections and recurrent oral ulcerations.

Common variable immunodeficiency

Failure in B differentiation and defective are the main features of this condition. Aphthous like ulceration, enamel hypoplasia and pseudomembranous candidosis are the possible oral complications.

Selective IgA deficiency

There is failure of terminal differentiation of IgA producing B-cells resulting in recurrent sinusitis and increased risk of oral infections. Tonsilar and adenoidal hypoplasia may also present.

Wiskott - Aldrich syndrome

This syndrome causes cell membrane defects affecting haemopoietic stem cell derivatives. Related oral conditions are herpetic and candidal infections, spontaneous gingival bleeding, perpura petechiae, and mucosal ulcers.

Ataxia telengectasia

 Chromosomal abnormality leading to reduced T-cells. Oral manifestations are severe ulcers, palatal non-Hodgkin’s lymphomas, palatal telengiectesia and facial hypotonia.

Di George syndrome

Main feature of this syndrome is embriopathy of thymic development. Related oral conditions are severe mucocutaneous cadidosis and enamel hypoplasia. Other clinical manifestations are prominent forhead, short philtrum and hypertelorism.

Down’s syndrome

Main immunological impact is on phagocytic cells.  Related oral diseases are ANUG and early severe periodontitis. Delayed eruption of teeth also possible,

Chediac Higashi syndrome

Cause phagosome lysosome adhesion abnormalities. Oral ulceration, severe periodontits and lymphadenopathy could be seen.

Neurtopenia

Neutrophil deficiency causes reduced immunity. Oral manifestations are recurrent oral ulcers on lips, tongue and buccal mucosa gingivitis and enamel hypoplasia. In cyclic neutropenea oral lesions may also appear cyclically.

Chronic granulomatous disease of childhood

Cause abnormal production of superoxide free radicals. Oral lesions are severe gingivitis and periodontitis, eczematous lesions in the face and lips, invariable lymph node enlargement.

Leukocyte adhesion defects

Defects in mobility, chemotaxis, adhesion and endocytosis are present. In these patients recurrent bacterial infection of the mucosa and skin could be present. Gingivitis occurs as soon as the primary teeth erupt.

Neutrophil G6PD deficiency

Recurrent infections are common in this kind of patient.

Hereditary myeloperoxidase deficiency

  Recurrent infections and candidosis are common.

Secondary (acquired) immunodeficiency disorders and their related oral diseases

Drug induced immunodeficiency

Immunosuppressive Drugs

Nowadays immunosuppressive drugs are used more frequently and extensively in medical practice (E.g. renal transplant, organ transplant, management of immune mediated diseases). Commonly used immunosuppressants include corticosteroids, such as prednisone and prednisolone, cytotoxic drugs, such as azathioprine, chlorambucil, cyclophosphamide, and methotrexate, and others such as antilymphocyte immunoglobulin and cyclosporine.

The most common complication is infection. In times infection can be fatal. Fungal and viral infections particularly candidal are the common oral conditions.

Radiotherapy

This is one modality of cancer treatment which causes immunodeficiency as a side effect. Myalosuppresion is the main effect. Oral complications are xerostomia and ulcerations. According to the site treated, late effects reflect both the loss of slowly proliferating and local endarteritis which produces ischemia to the related site leading to increased susceptibility to infections. Osteoradionecrosis is one such complication following radiotherapy for oral cancer.

Infections

HIV infection

HIV can be presented with variety of oral manifestations and oral diseases which sometimes first sign to be present. HIV is a retro virus which responsible for acquired immunodeficiency syndrome (AIDS). It attacks mainly CD4 cells. There is a progressive and profound reduction of CD8 cells and CD8 cells as well. Virus can attack monocytes, macrophages, dendritic cells and B cells also. This will result in reduced immunity of the patient. Oral disease related with AIDS can be classified into three groups    

·         Lesions strongly associated with HIV infections

·         Lesions less commonly associated with HIV

·         Lesions rarely associated with HIV

Group 1 – lesions (strongly associated with HIV)

v  Candidosis – pseudomembraneous (most common)

                      Erythematous

v  Hairy leukoplakia

v  Kaposi’s sarcoma

v  Non Hodgkin’s lymphoma

v  Linear gingival erythema

v  Necrotizing gingivitis

v 

Necrotizing periodontitis

Group 2 – lesions(less commonly associated)

v  Bacterial infections  -  Mycobacterium intercellularae

                                Mycobacterium tuberculosis

v  Viral infections –      Herpes simplex

                                    Human papilloma virus

                                    Varicella zoster virus

v  Salivary gland diseases –     Xerostomia

                                                Major gland diseases

v  Miscellaneous –         Melanotic pigmentation       Thrombocytopenic purpura

                                    Necrotising stomatitis

Group 3 – lesions (rarely associated)

v  Bacterial infections –           A. Isrelii

                                                E- Coli

v  Viral infections –      Klesiella pneumonia

                                    CMV, Molluscum contagiosum

v  Fungal infections –   Cryptococcus neofomnas

                                    Mucormycosis

                                    Zygomycosus

                                    Aspergillosis

v  Neurological diseases –       Facial palsy

                                                Trigeminal neuralgia

v  Due to drug therapy of AIDS -  Ulcers, Erythema multiforme, Lichenoid reactions, Toxic epidermolysis, SCCA

Myaloproliferative Disorders

Myeloma, leukaemias are the common disorders which result in reduction in immunity and give rise to oral symptoms.

Leukaemia

This is a relatively rare disease with an incidence of about 10 per 100000 per year. Leukaemia classified as being acute or chronic and myeloid or lymphoid origin. More than ½ of patients present acutely. General classification is as follows.

o   AML – Acute myeloid leukaemia

o   ALL – Acute lymphoblastic leukaemia

o   CML – Chronic lymphoblastic leukaemia

The disease has unknown aetiology but several factors such as radiation, chemicals, drugs, genetics, viruses, have been associated. The effect of leukemic overproduction of white cells is to suppress other cell lines of the marrow leading to immunodeficiency. Impairment of normal haemopoisesis resulting anaemia, granulocytopenia and thrombocytopenia and patient is having attenuated immunity. Oral effects of acute leukaemia are

§  Gingival swelling

§  Mucosal ulceration

§  Leukaemic deposits

o   Acute myalocytic leukaemia –

§  Grossly swollen gingivae

§  Ulceration in palatal aspect of anterior teeth

Lymphomas

Lymphomas are more common than leukaemias. Result in abnormal proliferation of lymphoid system. Hence can occur in any site where lymphoid tissue is found. According to the histopathological appearance can be classified into

v  Hodgkin’s lymphoma – hall mark is Reed-Sternberg cell derived from germinal centre B-cell or rarely peripheral T-cell. Accounts for 25% of malignant lymphomas. Lymph node enlargement most often in cervical region. They are usually painless and rubbery in consistency.

v  Non- Hodgkin’s lymphoma- more common and comprise rest of cases. Adults are predominantly affected. Lymphomas present inside the oral cavity usually soft, painless swellings which way become ulcerated by trauma. Infection is also common.

Neoplastic proliferations of lymphopoietic portion of reticulo endothelial system result in attenuated immunity

Metabolic Disorders

Conditions such as malnutrition, iron deficiency result in redused cell s mediated immunity. Diabetes mellitus is the other important and common condition which has oral complications due to reduced immunity.

Diabetes mellitus

One of the most common endocrine disorder that occur due to deficiency of insulin or due to impairment of insulin function which result in high blood sugar levels. This high blood sugar produces the classical symptoms of polyuria (frequent urination), polydipsia (increased thirst) and polyphagia (increased hunger).

There are three main types of diabetes:

·         Type 1 diabetes: results from the body's failure to produce insulin, and presently requires the person to inject insulin. (Also referred to as insulin-dependent diabetes mellitus, IDDM for short, and juvenile diabetes.)

·          Type2 diabetes: results from insulin resistance, a condition in which cells fail to use insulin properly, sometimes combined with an absolute insulin deficiency. (Formerly referred to as non-insulin-dependent diabetes mellitus, NIDDM for short, and adult-onset diabetes.)

·          Gestational diabetes: is when pregnant women, who have never had diabetes before, have a high blood glucose level during pregnancy. It may precede development of type 2 DM.

Other forms of diabetes mellitus include congenital diabetes, which is due to genetic defects of insulin secretion, cystic fibrosis-related diabetes, steroid diabetes induced by high doses of glucocorticoids, and several forms of monogenic diabetes.

In DM defective phagocytosis is proboly the main cause for reduced immunity. The associated oral diseases are

·         Susceptible for infections (candidosis)

·         Sialadinosis

·         Complications due to Xerostomia (due to polyuria and dehydration)

·         Periodontal disease (exaggerated response to plaque)

·         Lichenoid reactions due to antidiabetic drugs

Autoimmune diseases

Chronic autoimmune hepatitis, SLE like diseases are autoimmune disease related with T- cell defects. These patients have increased risk for oral infections.

Systemic lupus erythematosus

SLE is inflammatory multisystem disorder with arthralgia and rashes as the most common clinical features. This condition is 9 times more common in women than in men with a peak age of onset between 20-40 years. Loss of self tolerance has several consequences there is impaired T-cell regulation on immune system leading to immune deficiency. Oral manifestation is oral ulceration.

Miscellaneous Causes

Neutropenia

Neutropenia  is defined as circulatory neutrophil count below 1.5 ×10⁹ /L. Acquired causes may be viral infections, severe bacterial infections, immune nurtopenia (autoimmune neonatal netropenia) inherited causes are ethnic (common in black races), cyclic  neutropenia(genetic defect with neutropenia every 2-3 weeks)

Clinical features

Frequent infections, often serious, characteristic glazed mucositis and oral ulcerations are common.

Sarcoidosis

Is a multisystemic disorder of unknown aetiology characterised by non-caseating  granulomas in many tissues and organs. It is commonly affects young adults and usually presenting with bilateral hilar lymphadenopathy, pulmonary infiltration and skin or eye lesions. There is depresses cell mediated reactivity and overall lymphopenia. Circulating T lymphocytes are low but B cells are slightly raised.

Lip swelling, gingival and palatal nodules can occur. Unilateral or bilateral parotitis with painful enlargement occurs in less than 10% of patients and some go on to develop xerostomia. Combined uveoparotid involvement is described as Mikulicz syndrome.

Sickle cell disease

Sickle cell disease is an autosomal dominant condition. Hb S results from a single base mutation of adenine to thymine which produces a substitution of valine for glutamate at sixth cordon of the β globulin chain. Sickling off cell under low O₂ concentration resulting a short red cell survival. Ther is increased blood viscosity and reduced blood flow result in thrombosis and infarction with chronic haemostasis. There is reduced immunity and low Hb levels. Infections are common in tissues susceptible to vaso occlusion.

E.g. bones, lungs, kidney

Oral manifestations are

·         Pallor of mucosa with jaundice

·         Delayed eruption

·         More prone to  osteomyalitis

·         Parasthesia of mental nerve

·         Bimaxillary proclination , high cheek bones

Some of the important immunodeficiency conditions which were discussed above with related oral disease conditions are important in several ways for the dental practitioner. Early diagnosis, appropriate referrals and management of oral complications of these conditions are the important duties that dental practitioner must deal with.

Proper tooth brushing techniques power point presentation

Proper tooth brushing techniques power point presentation with animations

• bass method: sulcular brushing
• The roll or rolling stroke method
• The stillman method
• THE MODIFIED stailman
• The charters method