Bacterial Infection of the Oral Cavity

 

Bacterial lesions causing ulcerative conditions in the oral cavity

1. Syphilis
2. Gonorrhoea
3. Tuberculosis
4. Leprosy
5. Actinomycosis
6. Noma

For paid courses, a detailed description of the bacterial infection of the oral cavity is given HERE.

Properties of Dental Materials- Terminology

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.

Dental Anatomy and Terminology

Anatomy of the tooth and surrounding tissues

Enamel: 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 the 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: It is a naturally occurring crevice in the enamel.

Crown: This is the part of the tooth that is visible and is above the gingival margin.

Root: This is the part of the tooth below the gingival margin; it is connected through cementum on its surface and the fibres of the periodontal ligament to the supporting bone.

Dental numbering system

There are numerous dental numbering systems to identify teeth and their maturity. The most commonly used system in Australia is the Federation Dentaire Internationale (FDI) system (see Figures). When communicating with a dentist, identify which numbering system is being used.

The FDI numbering system divides the mouth into quadrants. The first number indicates the quadrant and whether it is a primary or secondary tooth. The second number indicates the tooth; tooth numbering begins at the central incisor and counts backward to the molars.

Using the FDI numbering system, for adults, the quadrants are numbered as:

1. patient’s upper right is quadrant 1 
2. patient’s upper left is quadrant 2 
3. patient’s lower left is quadrant 3 
4. patient’s lower right is quadrant 4

For primary teeth in children, the quadrants are numbered as:

1. patient’s upper right is quadrant 5 
2. patient’s upper left is quadrant 6 
3. patient’s lower left is quadrant 7 
4. patient’s lower right is quadrant 8

Quick MCQ Test: 

Upcoming (Please check regularly to avail Free MCQ).

Ref: Therapeutic Guidelines 2019

Face bow

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:

1. in full mouth rehabilitation
2. when you want to give accurate crown and bridges 
3. when you need to alter VDO
4.  for diagnostic mounting
5. for the correction of the occlusion
6.  when you want to use inter-occlusal records except when you are making tooth supported prosthesis or a single tooth restoration
7.  when you are using cusp form teeth
8.  when you need balanced occlusion
9. when you want to do a gnathological study

Face bow for Hanau Non-Arcon Articulator

Multiple choice questions

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 the stipulated time frame.

3) Once you have finished answering the paper, press the submit button to see the answers .

4) After submission, you will see your result. The correct answer will be shown by a green tick and the wrongly answered question will have a red x in a circle. In either case you will get the correct answer in green colour and the explanation in magenta colour.

Your answers will not be saved automatically. Therefore, you need to write down your score yourself to keep a record of your progress

5) Once you are ready, press the start button.

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Dens in Dente

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: 

1. https://www.omicsonline.org/scientific-reports/srep147.php

Hypertension

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

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].

Radiographic Features

Radiographically, ameloblastoma typically forms round, cyst-like, radiolucent area with well-defined margins. The smallest lesions appear unilocular; whereas larger ameloblastoma may comprise a few large clustered cysts, giving 'soap-bubble’ or 'multilocular appearance' or  ‘honeycomb’ appearance (Fig 1) Expansion of the lesion may be on both, lingual and buccal side.

Fig. 1. Ameloblastoma: multilocular appearance

Differential Diagnosis

Other multilocular lesions that may mimic ameloblastoma radiologically include odontogenic keratocyst, giant-cell granuloma and odontogenic myxoma. Ameloblastoma with a single bony cavity simulate many types of cyst and tumour radiographically.

Treatment

The surgical options for ameloblastoma vary from simple enucleation (with or without bony curettage) to radical excision.

Ref: 

1. Medina A, Velasco Martinez I, McIntyre B, Chandran R. Ameloblastoma: clinical presentation, multidisciplinary management and outcome. Case Reports Plast Surg Hand Surg. 2021;8(1):27-36. Published 2021 Feb 22. doi:10.1080/23320885.2021.1886854

Supernumerary Teeth

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:

1. Oral pathology clinical pathologic correlation, Regezi, Sciubba, Jordan 4th Ed Saunders

Oral Candidiasis

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

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.