Academy of Dental Knowledge

You must know the properties of the materials used in dentistry to understand its function and how and why it works in oral cavity. It also helps in manipulating it. The main properties you should know about are following: Stress Strain Elasticity Modulus Elastic Limit Thermal Expansion Hygroscopic Expansion Setting Expansion To read the entire lecture (in premium Iridium course), click at the link HERE . Annealing: Annealing is a process of heating and cooling of metal in a controlled manner. It is done/designed to produce desired properties in a metal. it is typically done to make the metal softer, increase ductility, stabilise the shape and improve/increase the machinability. When we talk about annealing of gold foil, it typically is done to remove surface contaminants just before the condensation.

Anatomy of the tooth and surrounding tissues E namel:  This is the hard, calcified substance that makes the surface of a crown of a tooth. Dentin:   This is the calcified tissue that forms the major part of a tooth. In the  crown of the tooth, the dentine is covered by enamel. The pulp chamber of the tooth is surrounded by dentine. Pulp:  This is the organ at the centre of a tooth that contains blood vessels, connective and neural tissue, and cells that produce dentine-odontoblast. Blood vessels and neural tissue enter the tooth from the apex of the root. Gingiva:   This is the marginal part of the gum that surrounds the tooth where it  emerges from the deeper, supporting tissues. Periodontal ligament:  This is t he ligament that connects a tooth, by its root, to the supporting bone. Cementum:  This is the calcified tissue on the surface of the root of a tooth, which provides attachment for the periodontal ligament. Fissure:  I...

Face bow-for Whip mix Arcon articulator Face bow is a device that is used to transfer the relationship of upper jaw to the temporomandibular joint and the skull. The use of face bow are as follows: in full mouth rehabilitation when you want to give accurate crown and bridges   when you need to alter VDO   for diagnostic mounting for the correction of the occlusion   when you want to use inter-occlusal records except when you are making tooth supported prosthesis or a single tooth restoration   when you are using cusp form teeth   when you need balanced occlusion when you want to do a gnathological study Face bow for Hanau Non-Arcon Articulator Multiple choice questions JavaScript Quiz Project INSTRUCTIONS: 1) The duration of the examination is 70 minutes. 2) After 70 minutes, the paper will not submit itself automatically so that you can keep on solving it. But, in the real exam, this will not happen, so try to finish it within...

Dens invaginatus, dens in dente or tooth with in a tooth is a rare developmental anomaly. In it, the lingual pit is extended deep in to the crown or root, in later instance causing pulpitis. It is mostly seen in the maxillary lateral incisors but may be found in any anterior tooth. Dens in Dente-lateral incisors The cause of dens in dente in not known but role of genetic factor can not be established. In early stage, it can be treated by filling or endodontic treatment, if pulp is involved. A. showing Type I Dens Invaginatus in lateral incisors. Note- periapical cyst. B. Type II dens invaginatus in second premolar and C. Type III dens invaginatus in mandibular canine. [1] Ref:  https://www.omicsonline.org/scientific-reports/srep147.php

The 2017 ACC/AHA guideline for high BP in adults provides four BP categories based on the average of two or more in-office readings on 2 or more occasions: Normal:  Lower than 120 mm Hg systolic BP (SBP) and 80 mm Hg diastolic BP (DBP). Elevated:  120–129 mm Hg SBP and lower than 80 mm Hg DBP. Stage 1 hypertension:  130–139 mm Hg SBP or 80–89 mm Hg DBP. Stage 2 hypertension:  Higher than or equal to 140 mm Hg SBP or 90 mm Hg DBP.

Ameloblastoma is a rare head and neck tumor with an estimated annual incidence of 0.5 per million population. They constitute 1% of tumors and cysts involving the jaws and accounts for approximately 10% of the odontogenic tumors. Ameloblastomas are originated from the epithelial lining of odontogenic cysts, enamel organ or dental lamina, stratified epithelium of oral cavity or displaced epithelial remnants. They are primarily seen in adults during the third and fourth decade of life with no gender preference and more frequently located in the mandible (80%), especially in the angle and ascending ramus [1]. Even though they are benign and slow-growing lesions, ameloblastomas exhibit locally destructive behavior with a high recurrence rate. Thus, most relapses (50% and even over 80%) occur during the first 5 years after the primary surgery. The major contributing factor for recurrence seems to be the inadequate initial surgical procedure rather than the histological type [1]. Radiographi...

Extra numbers of teeth are known as supernumerary teeth. When they are present in the anterior maxilla in midline, they are known as mesiodens. When the extra teeth are present in the molar region as fourth molar, they are known as paramolar teeth. The anterior midline of the maxilla is the most common site whereas the maxillary molar area is the second most common site for supernumerary teeth. Supernumerary tooth-mesiodens in anterior mandible in midline [1] Radiograph showing mesiodens in anterior maxilla [1] The investigation involves routine blood examination and IOPA or OPG radiographs. Depending on the anticipated level of difficulty of the surgery, additional investigations may be advised. Treatment involves surgical extraction. Ref: Oral pathology clinical pathologic correlation, Regezi, Sciubba, Jordan 4th Ed Saunders

Oral candidiasis is a fungal disease that is caused by Candida albicans. It looks like a white  or creamy plaque or patch that can be wiped off with the help of a cotton swab or a tooth brush leaving a red base. Gingival thrush It occurs due to disturbance in the oral microflora due to antibiotics, corticosteroid, Xerostomia , immune defects especially in HIV infection, immunosuppressant, leukaemia or lymphomas and diabetes. It rarely occurs in a healthy individuals except in neonates. Chronic mucocutaneous candidosis: note the wide adherent plaque. Gram stain smear shows the Candida albicans hyphae. It should be differentiated from Koplik's spot or Fordyce's granules. The treatment involves treating the cause. Antifungal agents, for example, nystatin oral suspension or pastilles, amphotericin lozenges, or miconazole gel or tablets or fluconazole tablets can be given. Ref: 1. Oral diseases 2nd Ed. Crispian Scully, Roderick A. Cawson Churchill Livingstone

MALOCCLUSION Proposed by Edward H. Angle in 1890, the Angle Classifications are based on the relationship of the buccal groove of the mandibular first permanent molar and the mesiobuccal cusp of the maxillary first permanent molar. This classification is considered to be one of the most commonly used as its easy to use.

  Bleeding disorders: dental considerations Acquired or congenital bleeding disorders of dental treatment concern include haemophilia, von Willebrand disease, other factor deficiencies and thrombocytopenia. Some systemic conditions also interfere with haemostasis, such as kidney, liver and bone marrow disorders. Patients with bleeding disorders should be managed in a specialist setting, with appropriate consultation with the patient’s specialist or multidisciplinary team. Bleeding Disorders haemophilia von Willebrand disease Other factor deficiencies  thrombocytopenia Causes Bleeding disorder may be due to defect in platelet activation, function and contact activation.  It may also be due to defect in clotting proteins or antithrombin function.  The commonest caused of bleeding disorder are  warfarin von Willebrand disease aspirin Warfarin is the commonest anticoagulant that interferes by preventing the production of clotting factors by blocking vitamin K. von W...

Congestive Heart Failure Congestive heart failure or  h eart failure  occurs when the heart muscle weakens and doesn't pump enough blood as it should. When this happens, blood often backs up and fluid can build up in the lungs, causing shortness of breath. Certain heart conditions, for example,  coronary artery disease or  high blood pressure, gradually leave the heart too weak or stiff to fill and pump blood properly.  Signs and symptoms of congestive heart failure   Shortness of breath with activity or when lying down Fatigue and weakness Swelling in the legs, ankles and feet Rapid or irregular heartbeat Reduced ability to exercise Persistent cough or wheezing with white or pink blood-tinged mucus Swelling of the belly area (abdomen) Very rapid weight gain from fluid build-up Nausea and lack of appetite Difficulty concentrating or decreased alertness Chest pain if heart failure is caused by a heart attack

Antibiotic prophylaxis is recommended for invasive dental procedures that involve the manipulation of gingival tissue or periapical region or perforation of the mucosa when performed on high-risk individuals. Australian guidelines have provided a list of dental procedures that are likely to cause a high incidence of bacteraemia that always require prophylaxis. These are as follows: Tooth extraction. Periodontal surgery, subgingival scaling and root planning. Replantation of avulsed teeth. Other surgical procedures such as implant placement or apicoectomy. Procedures that cause a moderate incidence of bacteraemia might be considered for prophylaxis if multiple procedures are being conducted, in cases where the procedure is prolonged, or in the setting of periodontal disease. Antibiotic prophylaxis is not recommended for procedures with a low possibility of bacteraemia such as: Local anaesthetic injections. Dental X-rays. Treatment of superficial caries. Orthodontic appliance placement a...

The laboratory findings in haemophilia will be as follows. APTT (activated partial prothrombin time) -prolonged PT (prothrombin time)-normal BT (bleeding time)-normal [1] or increased [2] Factor VIII-C- low Factor VIIIR:Ag [von Willebrand factor] and factor VIIIR:RCo [Ristocetin cofactor]-normal Ref: Crispian Scully, Roderick A. Cawson Medical problems in dentistry page 142 5th Ed.  https://www.cdc.gov/ncbddd/hemophilia/diagnosis.html

Oral Erythroplakia Erythroplakia is a clinical term for a potentially malignant fiery red lesion that cannot be attributed to any particular condition. Signs and Symptoms Lesions are usually asymptomatic and isolated, and commonly appear on the floor of the mouth, tongue, soft palate and buccal mucosa. Lesions may appear as smooth, velvety, granular or nodular plaques, often with clear margins.

Antimicrobials used in dentistry Chemotherapy is the use of chemicals to destroy or inhibit the growth of cells. Two broad classes of chemotherapeutic agents are used in pharmacology:  antimicrobials and  anticancer drugs.  The basis of antimicrobial chemotherapy is a differential sensitivity of the patient and microbe cells to the action of the drug. The drug may affect a structural component of the target cell which is not found in the patient, for example, the bacterial cell wall. Alternatively, a chemotherapeutic agent may inhibit a metabolic pathway peculiar to the microbe cells, for example, synthesis of folate.

      Normally there is one opening of the parotid gland which is located in buccal vestibule opposite the upper 2nd molar tooth.      Parotid fistula is a patent tract connecting a parotid gland or duct to the exterior apart from the parotid duct opening. Photo 1. Pre-operative picture of parotid fistula with leakage of serous fluid from the fistulous tract and scarring of surrounding area (red circle) [1]       Parotid fistula may be of two types     1. Glandular: It arises directly from gland. It shows minimal discharge during rest or eating. 2. Ductal: It arises from duct. It shows profuse discharge during eating. Parotid fistula may be extra oral or intraoral. Extraoral fistulas are seen in the preauricular region or near the angle of mandible (see photo 1 and 2). Photo 2. showing discharge of serous fluid from the right cheek in the angle of mandible region [2] Causes 1. After superficial parotidectomy. 2.   After drai...