Radiography: Radiation Safety

In earlier articles on radiography, you studied the effects of ionizing radiation on biological tissues. These effects can be divided into two types- Deterministic and Stochastic. Therefore, the radiation safety becomes of paramount importance white taking a radiograph.

 

CBI Books Head of Dental Department AIIMS-Patna for Corruption Charges


The Central Bureau of Investigation (CBI) has filed an FIR against former Head of the Dental Department of All India Institute of Medical Sciences (AIIMS)-Patna, Dr. Shailesh Kumar Mukul. He is accused of resorting to “unlawful means in conspiracy with others” during the 2013 and 2019 period.  

Coronavirus Disease: Seven Essential Norms You Should Follow to Help Yourself during Home Quarantine Period

Coronavirus Disease-COVID-19: Seven Essential Norms You Should Follow to Help Yourself during Quarantine Period

The following category of people should stay at home under home quarantine status. This category includes a person with suspected coronavirus infection, those under investigation but not needing hospitalization. Also, the one who had had confirmed coronavirus infection was hospitalized earlier but now has been discharged and medically stable. These people should stay at home under quarantine conditions.

Radiography: Effects of Radiation on Oral Tissues

Dentists often encounter cancer patients, who are to undergo radiotherapy or have received it in the recent past. Besides cancer therapy, these patients need dental treatment for different ailments. Therefore, it becomes paramount important for a dentist to know the effects of large doses of ionizing radiation on oral mucosa.

In this section, we shall talk about the effects of radiation on oral tissues.

Radiography: Radiation Biology

Radiation Biology 

Radiation biology is the study of effects of ionizing radiation on living systems. In this article we shall talk about the harmful effects of ionizing radiation on tissues, how does it occur, and how sensitive different types of cells are?

The effects of radiation on the tissues can be divided into 2 broad categories. The Deterministic and Stochastic effects.

 

Radiography: Radiation Physics

In this article termed as radiation physics, we shall talk about the ways, the x-rays are produced, the events that occur at atomic level during their production and how can one save oneself and others.

Production of X Rays  

Electrons that travel from the filament to the tungsten convert part of their kinetic energy into x-ray photons. This phenomenon occurs by the formation of bremsstrahlung and characteristic radiation.  

Dental Amalgam Alloys

Dental Amalgam 

In this section, we shall discuss the composition, type and properties of the dental amalgams alloys used for restoration purpose in posterior teeth as per following format. The source of these notes, MCQs and explanation is Phillips’ Science of Dental Materials, 12th Ed and Sturtevant’s Art and Science of Operative Dentistry.

Why is Zinc Not Added to Dental Amalgam?

Why is Zinc Not Added to Dental Amalgam?

Zinc as such does not participate in the amalgamation process or in the setting reaction of silver amalgam alloy with mercury during and after the completion of the restoration process.

Covid 19: Test Yourself-How Much Do You Think, You Know Coronavirus?

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Indian Prosthodontic Society holds its 46th conference in Mangalore

Indian Prosthodontic Society (IPS) holds its 46th conference in Mangalore on 15th November 18.

19th National PG Student Convention of Indian Prosthodontic Society will be held in Gujarat

Radiation Protection of Pregnant Women

Is there a safe level of radiation exposure for a patient during pregnancy?

Dose boundaries do not apply for radiation exposure of patients, since the decision to use radiation is reasonable depending upon the individual patient situation. When it has been decided that a medical procedure is justified, the procedure should be optimized. This means that the conditions should achieve the clinical purpose with the appropriate dose. Dose limits are determined only for the staff and not for patients.

Local Anaesthesia

Local anaesthesia means a no pain sensation in a particular area supplied by a specific nerve. The correct term is local analgesia but commonly not used? It is given with the help of 2 ml or 5 ml single use disposable syringes. 
The anaesthesia is an inseparable part of surgery. It provides maximum patient comfort and cooperation. Without anaesthesia, the advancement in surgeries could not have been achieved. In 3rd molar surgery a patient may opt for general anaesthesia or local anaesthesia. The local anaesthesia may be supplemented with sedation for increased comfort. 
 

Advantages of Local Anaesthesia 

 
Local anaesthesia has the following advantages over general anaesthesia. 
  1. It is safe, efficient and predictably effective in almost all patients. 
  2. It is inexpensive. 
  3. It is easy to administer. 
  4. For healthy patient, no monitoring is needed by equipment 
  5. The patient does not lose consciousness with an intact gag reflex during anaesthesia. 
  6. Procedures under local anaesthesia, hospitalization is not needed, therefore, for patients’, it is convenient. 
  7. To administer local anaesthesia, no preoperative fasting is required. 
  8. A patient can be discharged immediately without waiting for recovery or an escort. 
 

Limitations of Local Anaesthesia 

 
Despite the huge number of advantages, the local anaesthesia does have certain disadvantages. They are as follows. 
  1. It cannot be used in a non-cooperative patient; for example, younger children. 
  2. It cannot be used in a patient with fear of needles. 
  3. It cannot be used in an anxious or nervous patient. 
  4. It is only suitable for short procedures which are of less than 30-minute duration. 
  5. It cannot anesthetize the locally inflamed tissues. 
 

Composition of Local Anaesthesia 

 
The local anaesthetic solutions mainly contain the following contents. 
  1. Local anaesthesia base. 
  2. Hydrochloride salt for solubility and stability. 
  3. Buffering agents. 
  4. Preservatives; e.g., Methyl Paraben 
 

How does local anaesthetics prevent the conduction of dental pain? 

 
Local anaesthetics inhibit the generation of electrical impulses and their conduction along the neuronal axon membrane, by reversible blockade of sodium ion channels. 
There is a continuous imbalance of sodium and potassium ions between the cytoplasm of neurons and the intercellular fluid. This is maintained at about 25 times more potassium intracellularly and 15 times more sodium in interstitial space. 
 

Mechanism of action 

 
The molecule of local anaesthetic agent enters the neural cell through neurilemmoma from interstitial fluid by a simple diffusion process. Then in the acidic environment of a neural cell, it breaks itself in its components and acts on the sodium influx gate and blocks it, thus blocking the generation of action potential, thus blocking signal conduction along the nerve cell membrane. The local anaesthesia cannot act on sodium influx gates from outside the nerve cell. It must enter the nerve cell. 

Question: What happens when the area surrounding the nerve gets inflamed?  

Once the tissue is inflamed, the interstitial fluid becomes acidic in nature. In an acidic environment, the local anaesthetic molecule breaks down. A broken local anaesthetic molecule cannot pass through the cell membrane by a simple diffusion process and thus cannot produce its effect.
 
This is the reason a local anaesthetic cannot produce its effect in an inflamed tissue or is not so effective in an inflamed area. 

Question: Why does LA not function efficiently in an inflamed environment?   

Answer: The molecule of local anaesthetic agent enters the neural cell through myelin sheath from interstitial fluid by a simple diffusion process. Then in the acidic environment of a neural cell, it breaks itself in its components and acts on the sodium influx gate and blocks it, thus blocking the generation of action potential, thus blocking signal conduction along the nerve cell membrane. The local anaesthesia cannot act on sodium influx gates from outside the nerve cell. It must enter the nerve cell.
    
Question: What happens when the area surrounding the nerve gets inflamed? 
  
Once the tissue is inflamed, the interstitial fluid becomes acidic in nature. In an acidic environment, the local anaesthetic molecule breaks down. A broken local anaesthetic molecule cannot pass through the cell membrane by a simple diffusion process and thus cannot produce its effect.
  
This is the reason a local anaesthetic cannot produce its effect in an inflamed tissue or is not so effective in an inflamed area.