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Viva voice questions In Gypsum Products

Viva voice questions in Gypsum Products

Define Cast?

A reproduction of the shape and features of. Surface made from an impression of the surface.

what is model?

A positive likeness of an object

What is Dental plaster?

The bet form of calcium sulfate hemihydrate

what is Dental Stone?

The alpha form of calcium sulfate hemihydrate

Define Die?

A reproduction of a prepared tooth made from a gypsum product, epoxy resi , a metal or a refractory material.

what is Alabaster?

Alabaster is a form of gypsum. It is believed that the alabaster is used in the building ofKing Solomon’s temple.

Define Hygroscopic expansion?

The amount of setting expansion that occurs when a gypsum bonded casting investment is immersed in water

what is Normal setting expansion?

The amount of setting expansion that occurs when a gypsum bonded casting investment is allowed to set in air.

Define wet strength or green strength?

wet strength or green strength is the strength obtained when excess waster than that required for hydration of hemihydrate is left in the specimen.

what is the most commonly used accelerator in gypsum products?

Potassium sulfate and Sodium chloride accelerate the setting reaction of gypsum products. But at higher concentration NaCl act as retarder.

powdered gypsum added to hemihydrate also accelerate the setting reaction as these particles act as nuclei of crystallisation.

Viva voice questions-Dental materials

what are the uses of gypsum products in dentistry?

  • for the preparation of study models
  • are important auxiliary materials for dental laboratory operations that are involved in the production of dental prostheses
  • various types of dental plaster are produced, modified for specific property requirements,and used to form moods and casts on which dental prosthesis and restorations are constructed.
  • Impression plaster is used to take impression of oral and Maxill o facial structures
  • Dental Stone is used to prepare model, master cast or die.

The alpha hemihydrate is called as

Artificial Stone, die stone or improved stone

Click here for Amalgam viva questions

what are the differences between alpha hemihydrate and beta hemihydrate?

alpha hemihydrate(dental stone) consists of smaller, regularly shaped crystalline particles in the form of rods or prisms.

beta hemihydrate consists of large, irregularly shaped crystal particles with capillary pores.

what are the factors that cause tease in setting expansion?

  • Less water powder ratio
  • allowing setting under water
  • increased rate of spatulation
  • fine or smaller silica particles
  • alpha hemihydrate

what are the factors that cause decrease in setting expansion?

  • more water powder ratio
  • addition of modifiers like potassium sulfate, NaCl, borax
  • reduced spatulation

what is the reason for the rough or chalky surface of the cast?

The rough orchalky surface of the cast is due to

  • high speed accelerator
  • air incorporation in the mox
  • not waiting for 20 mins before pouring.



A Layman’s Guide to the Dentist

A Layman’s Guide to the Dentist





I. Prevent the cavities problem


II. Stop the Tooth Loss


III. Get Brighter Smile


IIII. Improve the health


V. Can save the money


VI. Improve the relations




viva voice Questions in Amalgam for dental students

Viva voice questions in Amalgam for Dental students

  • What is amalgam?

amalgam is an alloy that contains mercury as one of its constituents.

  • What is the ADA specification number for Amalgam?

ADA specification number for Amalgam is 1

  • What is Amalgamation?


  • What is Trituration.

The mixing procedure of amalgam alloy with mercury is technically called as trituration.

  • Define condensation?

Special instruments are used to forces the plastic mass into the prepared cavity by a process known as condensation.

  • What is Dynamic creep?

Dynamic creep is the deformation of set Amalgam during function. Because of the creep Amalgam restoration extends out of the cavity preparation and increases its susceptibility to marginal breakdown.

What is creep?

Creep is the time dependent plastic deformation which occurs when a metal is subjected to a constant load near its melting point.

Delayed expansion occurs if the amalgam mic contaminated with moisture during trituration or condensation.

The expansion begins 4 or 5 days after condensation and results in hyper occlusion and cracks in tooth. This restoration  will cause pressure in pulp all direction will cause intense pain.

What is the working time of Amalgam?y

Working time of Amalgam is 3 to 4 minutes.

Which constituent of Amalgam alloy decreases expansion?

Tin controls the reaction between silver and mercury. Without tin, the reaction would be too fast and the setting expansion would be unacceptable. Tin reduces the rate of reaction and the expansion to optimal values.

What is the cause for mercury intoxication in dental office?

Mercury intoxication in dental office mainly results from Inhalation of mercury vapours 

What is advantage of minimal mercury technique? 

The advantage of minimal mercury technique is greater plasticity and adapts well to cavity walls.

What is minimal mercury technique or Eames technique?

   The most obvious method for reducing the mercury content of the restoration is to reduce the original mercury/alloy ratio.According to Eames technique alloy and mercury ratio should be 1:1. In 1959 this technique was introduced by Eames.

How to control the setting time of Amalgam?

The setting time is best controlled by altering the trituration speed or trituration time or both. Spherical alloys require less amalgamation time than the lathe cut alloys.

What is delayed expansion?

The expansion begins 4 or 5 days after condensation and results in hyper occlusion and cracks in tooth. Delayed expansion occurs if the Amalgam mix is contaminated with moisture during trituration or condensation.

Viva voice questions in Impression materials

What is the composition of silver alloy?








What are the functions of constituents in the silver alloy powder?


Major element in the reaction 

Whitens the alloy

Decrease the creep

Increase the strength 

Increase the expansion on setting

Increase the tarnish resistance in the resulting Amalgam 


Controls the reaction between silver and mercury 

Reduces strength and hardness 

Reduces the resistance to tarnish and corrosion 


Increases hardness and strength 

Increases setting expansion 


Acts as a scavenger or deoxidiser

It causes delayed expansion

Platinum and palladium improves the hardness. Indium reduces mercury vapour and improves wetting.

What isTarnish?

Tarnish is surface discolouration or slight loss of surface finish or lustre of a metal. The discolouration of Amalgam is due to formation of black silver sulfide.

What is corrosion?

Corrosion s the actual deterioration of the metal by reaction with environment. Tin chlorides and oxidesare the corrosion products of low copper alloys whereas copper oxide is the corrosion of high copper alloys.

What are the mixing variables of Amalgam?

Undermixing, normal mixing and over mixing are the three mixing variables that result from variations in condition of trituration of the alloy and mercury. The undermixed Amalgam appears dull and is crumbly, the normal mix appears shiny and separates in a single mass from capsule and the overmixed Amalgam appears soupy and tends to stick to the inside of the capsule

What is the necessity of finishing and polishing of amalgam?

Amalgam without finishing and polishing will have a rough surface microscopically and results in concentration cell-type corrosion.

Which one is preferable traditional low copper or high copper amalgam?

Compared to traditional low copper Amalgam, high copper amalgams became the material of choice because high copper Amalgam have

High early strength 

Low creep

Good corrosion resistance 

Good resistance to marginal fracture

What is the recommended force for the condensation of Amalgam?

The average recommended force is 3-4 pounds r 13 -18 Newtons 

The percentage of zinc present in non zinc containing dental amalgam?

Alloys containing less than 0.01% of zinc are classified as nonzinc alloys with more than 0.01 of zinc are classified as zinc containing alloys.

Uses of zinc

Reduces brittleness

It reacts rapidly with oxygen and their impurities and prevents the oxidation of more important elements like silver, copper or to . Thus it acts as deoxidiser or scavenger 

Better handling property

If the Amalgam is contaminated with moisture during trituration or condensation,an causes delayed expansion. 

What is the cause for delayed expansion?

Delayed expansion is due to pressure exerted by hydrogen gas, which is a corrosion product evolved during the reaction between zinc and moisture. If the Amalgam is contaminated with moisture during trituration or condensation,an causes delayed expansion.

What is the use of cavo surface angle for Amalgam restoration?

Cavosurface angle for Amalgam restoration is 90 degrees and forms a butt end.butt end as it increases compressive and tensile strengths. Resistance to compression forces is the most favourable strength characteristic of Amalgam. Because amalgam is strongest in compression and much weaker in tension and shear, the cavity design should maximise compressive stresses in service and minimise tension or shear stresses.

What are the aims of condensation?

To adapt the mix to the cavity wall

Removes excess mercury 

Proper condensation increases the strength and decreases the creep of the Amalgam.

Condensation should be started at the centre and the condenser point is stepped sequentially towards the cavity walls

What is the need of carving and finishing of Amalgam restoration?

Carving and burnishing is done to reproduce the tooth anatomy and to get a smooth surface respectively.

Carving should not be started until the amalgam is hard enough to offer resistance to carving instruments 

A scrapping or ringing sound should be heard when it is carved

Polishing also required as it minimises corrosion and prevents adherence of plaque 

Final polishing should be delayed at least 24hrsafter condensation 

What are the effects of mercury toxicity?

Mercury is absorbed through skin, lungs or GIT, most commonly by lungs and penetration into the tooth from the restoration. Increase in exposure causes toxicity  which may associated with symptoms like weakness, fatigue, irritability, dizziness, insomnia, weight loss.

What are the safety measures to avoid mercury toxicity?

Mercury should be kept in an unbreakable container that are tightly sealed. 

Spills and leaks should be cleaned up immediately by approved methods

Water spray and a high volume evacuation should be used when removing an old amalgam restoration or finishing a new one

Glasses and disposable face mask should be worn to reduce hazards associated with flying particles and the inhalation of Amalgam dust

Amalgamators that completely enclose the arms and amalgam capsules during trituration should be used

Since Mercury vaporises at room temperature, hospitals should be well ventilated to minimise the mercury level in the air

Use of gloves is must.

How to dispose excess mercury or amalgam?

The potential hazards of mercury can be greatly reduced by attention of a few precautionary measures.

All excess mercury, including waste, disposable capsules, and amalgam removed during condensation should be collected and stored in well sealed containers.

Proper disposal through reputable dental vendors is mandatory to prevent environmental pollution.

Amalgam scrap and materials contaminated with mercury or amalgam should not be incinerated or subjected to heat sterilisation 

If mercury is spilled, it must be cleaned as soon as possible. It is extremely difficult to remove mercury from carpeting 

Ordinary vacuum cleaners merely disperse the mercury further through the exhaust.

Mercury suppressant powders are helpful, but these should be considered temporary measures 

If mercury comes in contact with the skin, the skin should be washed with soap and water.

How to control plaque in Children

How to control plaque in children?

Generally kids don’t have interest in tooth brushing. It is very difficult task for parents to make them brush. Proper brushing is necessary to avoid so many dental problems. Prevention is better than repair and replacement so brushing has more importance in oral hygiene methods. 



Two main dental disease, dental caries and periodontal disease frequently begin in childhood and often have long sequelae, therefore to parent these problems primary preventive dental care must begin equine life berthed onset of these diseases.

Finger tooth brushes are available in the market for brushing of baby teeth.

What is Dental Plaque ?

Dental plaque is the soft deposits adhering to the tooth surface or other hard tissues in the oral ca it’s. These deposits may also seen on the removable and fixed restoration.  Dental plaque is composed primarily of microorganisms. Various microorganisms are present in dental plaque such as bacterial species and non bacterial species like yeasts, Protozoa and viruses. 20%-30% of Plaque consists of organic and inorganic materials derived from saliva, gingival crevicular fluid, and bacterial products. Organic constituents in the plaque include polysaccharides, proteins, glycoproteins and lipid. The inorganic component of plaque is primarily calcium and phosphorus,with trace amounts of other minerals such as sodium, potassium and fluoride. 

Dental plaque induced Gingival Diseases

Formation of dental plaque:-

Dental plaque is white, grayishor yellow and may be readily visualised on teeth after1 to 2 days with no oral hygiene ensure. Plaque is typically observed in the gingival third of the tooth surface, where it accumulates without disruption. The process of plaque formation can be divided into three phases.

  1. The formation of the dental Pellicle
  2. Initial colonisation by bacteria
  3. Secondary colonisation and plaque maturation

How to control plaque?


  1. Mechanical plaque control
  • Tooth paste
  • Tooth brush
  • Dental floss
  • Oral irrigation 
  • Interdental cleaning aids
  1. Chemical plaque control
  • Mouth wash
  • Chlorhexidine

How to identify bacterial plaque deposits?

Disclosing solution is used to identify bacterial plaque. Disclosing solution is a preparation in liquid, tablet that contains a dye or other colouring agentused to identify bacterial plaque deposits for instruction, evaluation and research. Disclosing solution is used in the case of

  • To educate patient
  • To give instructions to patient about the plaque control 
  • Self assessment by the patient
  • Evaluation of effectiveness of plaque control measures 


Toothpaste is a substance used with a toothbrush to remove bacterial plaque, material alba and debris from the gingiva and teeth.

Select the best ToothPaste for your Teeth 


You may have never noticed it before or if you have, you may not know that the colour mark on every toothpaste tube signifies a very important thing! Usually the mark on a tube can be any of these colours: red, blue, green and black. These colours signify if the toothpaste contains chemical or natural ingredients. Wondering what your toothpaste contains? This is what the following colours signify.

BLACK: This is the most dangerous colour. It clearly indicates a presence of chemicals in the toothpaste.

RED: This is slightly less dangerous than black as black coloured label means that the composition of toothpaste is a combination of natural ingredients and chemicals.

BLUE: Blue coloured mark indicates that the toothpaste contains natural ingredients combined with the presence of medication.

GREEN: This is the best of all as green coloured mark represents the presence of only natural ingredients.


The mechanical cleaning of teeth can be traced back to ancient times. Both powered and manual tooth brushes are available in the market. Always select the tooth brush with soft bristles and don’t use the same tooth brush for long time. 


How to select a Toothbrush and types of Toothbrushes


  • Pick a child-sized toothbrush with soft bristles.

Powered toothbrushes are useful for

  • Individual lack of moto skill
  • Handicapped patient 
  • Patients who have orthodontic appliances 

Dental floss:-

Types of dental floss



Flossing for children


Oral irrigation:-

Irrigation is the targeted application of a pulsates or steady stream of water or other irritant for a cleansing and therapeutic purpose. Oral irrigation can be done by patient or the clinician. Oral irrigation cleans adherent bacteria and debris fromthe oral cavity more effectively than do toothbrush and mouth rinse.

Mouth wash:-


Guidelines for home oral hygiene 

Prenatal counseling:-


Plaque control in infants 

It is generally recommended that parents begin cleaning the infants mouth by the time first tooth erupts. It is suggested that secure and consistent physical support with slow, careful movement is to be employed at all time. Most have suggested that the parent wrap a damp washcloth or a piece o gauze around the index finger and clean the teeth and gum pads once a day.

As more teeth erupt the parent can begin using as all soft toothbrush. At this age ToothPaste is not necessary and may interfere with visibility for the parent. Additionally, the infant will be unable the effectively expectorate, causing unwanted ToothPaste ingestion. Several methods of positioning the infants for daily oral hygiene procedures have been suggested. One effective method is to have the parent cuddle the infant in his or her arm with one of the child arms gently slipped around the parents back. In this ways the parent can stabilise the child with one hand and work with the other.

Plaque control in toddler


Plaque removal for their toddlers, children at the age begin to demonstrate an interest in the procedure and a desire to take part. Parents should encourage this behaviour and allow the child to attempt brushing procedures. Parents, should, however, be advised that the child efforts will be inadequate in thoroughly removing plaque. Therefore, the parent must perform a through plaque removal for the child at least once a day. As for the infant, it is so important to the parents methods of positioning andstblizing the child so that the parents will have maximum visibility as well as control over the child’s movements. 

The position selected for home plaque removal procedures will depend on the cooperation of the child. Many of the techniques employed with the infants may also be applied to the toddler. One of the most effective positions is to have the parents face each other while the child is supine on the parents knees. In this position, one parent assumes the role of brushes while the other parent stabilises the child.

Plaque control in the early school stage


Plaque control in the preadolescent:-

During pre adolescence, the child will gradually assume more responsibility for his or her own hygiene. In this age group they can do effective brushing and flossing. The children in this age group require instruction on proper brushing and floss techniques.

Plaque control in the adolescent 


Necrotizing Ulcerative Gingivitis causes, predisposing factors, symptoms and treatment

Necrotizing Ulcerative Gingivitis causes, predisposing factors, symptoms and treatment 

Necrotising ulcerative gingivitis also called as

  • Vincent’s infection 
  • Trench mouth
  • Acute ulceromembranous gingivitis
  • Phagedenic gingivitis
  • Fusospirochetal gingivitis
  • Acute ulcerative gingivitis

Necrotizing ulcerative gingivitis is a common specific type of gingivitis. The disease manifests both acute and recurrent phases. This inflammatory condition involves primarily the free gingival margin, the crest of the gingiva and the interdental papillae. On rare occasions the lesions spread to the soft palate and tonsillar areas, and in such instances the term Vincent’s angina has been applied.

The short form of acute necrotizing ulcerative gingivitis is ANUG. Acute necrotizing ulcerative gingivitis occurs in an epidemic pattern, sweeping through groups of persons in close contact, especially those living under the similar conditions. The trench mouth word is originated because the disease was especially prevalent among the troops in the trenches during the First World War. Similar sporadic outbreaks also occurred during second world war. Though this condition is uncommon in developed countries nowadays there has been a global increase associated with HIV infection.

The pattern of the spread of the disease, in many instances indicated that it was a contagious infection, but this is not accepted now. It occurs in groups of persons can be explained on the basis of similar predisposing conditions among the members of the group, which may cause gingivitis to develop in each, even though there is no actual contact between them.

Necrotizing ulcerative gingivitis may occur at any age, but is reportedly more common among young and middle aged adults, 15-35 years old. In developing countries, it is seen almost exclusively in children, related to poverty and malnutrition.

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Gum bleeding causes, symptoms and treatment plan

What are the causes of Necrotizing ulcerative gingivitis?

It is an endogenous, polymicrobial infection causing destructive inflammation due to the coexistence of several predisposing factors.  It is caused by a fusiform bacillus and Borrelia Vincentian a spirochete. These organisms may be present in small numbers in the healthy gingival flora. Both microorganisms dominate in this fusospirochetal disease, although other spirochetes, fusiforms and filamentous organisms are also found. It is likely that a number of factors disturb the host parasite relationship facilitating overgrowth of the organisms of the fusospirochetal complex.

What are the Predisposing factors for Necrotizing ulcerative gingivitis?

Sychological stress plays an important role in the development of necrotizing ulcerative gingivitis, since there is an increased frequency of the disease in people in the military services. Other predisposing factors include immunosuppression, smoking, upper respiratory tract infection, local trauma, poor nutritional status and poor oral hygiene.

HIV positive persons suffer from a severe form of necrotizing ulcerative gingivitis as the immune function deteriorated and this progress to HIV associated periodontitis.

Decreased resistance to infection is one of the most important predisposing factors in the development of necrotizing ulcerative gingivitis 

What are the symptoms of Necrotizing ulcerative gingivitis?

  • The disease is characterised by the development of painful, hyperaemic gingiva and sharply pushed out crater like erosionsof the interdental papillae and the free gingiva bleedwhen touched and generally become covered by a greyish green, necrotic pseudomembrane.
  • The ulceration tends to spread and may eventually involve all gingival margins.
  • It begins rateher commonly at a single isolated focus with a rapid onset.
  • A fetid odour ultimately develops that is extremely unpleasant.
  • The patient almost always complains of an inability to eat because of the severe gingival pain and the tendency for gingival bleeding.
  • The pain is that of superficial pressure. The patient usually suffers from headache, malaise and a low grade fever.
  • Excessive salivation with the presence of a metallic taste to the saliva is often noted.
  • Regional lymphadenopathy is usually present.
  • In advanced and more serious cases, there may be generalised or systemic manifestations, which may include leukocytes is, gastrointestinal disturbances and tachycardia

What is the cause for the recurrence of the Necrotizing ulcerative gingivitis?

After the necrotizing ulcerative gingivitis is cured, the crests of the onterdentlpapillae, which have been destroyed leaving a hollowed out area, constitute an area which retains debris and  microorganisms and can serve as an incubation zone. Such area, along with gingival flaps of erupting third molars, are ideal locations for organisms to persist and in many cases, the recurrence necrotizing ulcerative gingivitis will begin here.

Smears of material from the gingiva of necrotizing ulcerative gingivitis shows vast numbers of fusiform  bacilli and an oral spirochete, verious other spirochetes, filamentous organisms, vibrios, cocci, desquamated epithelial cells and varying numbers of polymorphonuclear leucocytes. The relative numbers of microorganisms present vary with the stage of the disease.

What is the treatment for Necrotizing ulcerative gingivitis?

The treatment of necrotizing ulcerative gingivitis is extremely varied, depending upon the individual dentists experience with the disease. Some prefer to treat this condition conservatively instituting only superficial cleansing of the oral cavity in the early acute stage of the disease with chlorhexidine, diluted hydrogen peroxide or warm saline water. This is followed by thorough scaling and polishing. Topical anaesthesia may require to reduce the pain during this procedure. Antibiotics are also advised along with local treatment. The usual case of necrotizing ulcerative gingivitis begins to subside in 48 hours with adequate treatment and there may be little evidence afterwards of the presence of the disease. Sometimes there may be considerable destruction of tissue, interdental papillae and marginal gingiva and this may be evidenced after regression of the disease by the punched out appearance of the interproximal gingiva and the apparent gingival recession. Recontouring  of gingival papillae is usually required, this can be accomplished by proper use of round toothpicks or by gingivoplasty. Treatment cannot be considered complete until the gingiva tissue contours almost normal. Necrotizing ulcerative gingivitis recurs with considerable frequency in patients who have already been treated.

Possible viva voice questions in Necrotizing Ulcerative Gingivitis:-

  • Why Necrotizing ulcerative gingivitis is called as Trench mouth

During world war 1, when the troops suffered severely from the disease. It was here that the term trench mouth originated, since the disease was especially prevalent among the troops in the trenches. When the allied troops living under poor sanitary conditions in the trenches and inadequate diet are the causes for this disease.

  • What are the predisposing factors for this disease?

Psychological stress, Immunosupression, smoking, upper respiratory tract infection, local trauma, poor nutritional status and poor oral hygiene.

  • What are the microorganisms found in this disease?

Fusiform bacillus and Borrelia Vincentian-a spirochete 

  • What are the symptoms or clinical features?

Painful, hyperaemic gingiva and sharply punched out crater likeerosions of the interdental papillae, gingival bleeding, gingiva covered by greyish green, necrotic pseudo membrane, excessive salivation, metallic taste.

Dental Plaque Induced Gingival Diseases

Medical word for gum bleeding is “gingivitis”. Gingivitis  is inflammation of the gingiva. Plaque induced gingivitis is the most common form of gingival disease. This may occur on a periodontist with no attachment loss or on a periodontist with a previous attachment loss that is stable and not progressing. Plaque induced gingival disease is the result of plaque bacteria and defence cells of the host

What are the features of the healthy gingiva?

  • The healthy gingiva fits snugly around the teeth, filling each interproximal space between the teeth to the contact area.
  • The gingiva ends in a thin delicate edge called the free gingiva, which s adherent to the tooth. A jet of air from a syringe will blow the free gingiva away from the tooth surface, but the gingiva settles back into place quickly.
  • The colour of the normal gingiva is pale, cool coral pink
  • In adults, the tissue is dense, firm and insensitive to maderate pressure, it does not bleed easily and it has a stipples orange peel surface
  • The free and attached gingiva blends smoothly with the redder, glossy, unstippled alveolar mucosa of the vestibule and floor of the mouth.
  • In children , the gingiva is not stipples and appears redder and more delicate.
  • Attached gingiva is firmly bound down to the underlying one to form a tough mucoperiosteum.

Which age group is affected by Gingival Diseases?

It is generally accepted that periodontal disease is world wide in distribution and that there is no age group except in very young infants in which it does not occur. Although all races are affected, there is some difference in incidence between diff races and different countries. Men were affected more frequently than women.

This Bactria and host interaction is modified by local and systemic factors.

Local Factors:-

  1. Microorganisms
  2. calculus
  3. food impaction
  4. Faulty or irritating restorations or appliances
  5. mouth breathing
  6. tooth malposition

systemic Factors:-

  1. Nutritional deficiencies
  2. drug action
  3. Endocrine changes associated with puberty, pregnancy, menstrual cycle, and diabetes mellitus
  4. Allergy
  5. Heredity
  6. Psychic phenomena
  7. Specific granulomatoud infections
  8. Neutrophil dysfunction
  9. Immunopathies


Many varieties of microorganisms usually grows as biofilm or plaque, for the most part, on the self cleansing areas of the teeth, particularly below the cervical convex it you of the crown and in the cervical areas. Smears of the material taken from the normal gingival sulcus, the gingival sulcus in a case of marginal periodontitis or from the gingival pocket in advanced periodontal disease will reveal several microorganisms of many different types. Prominent among these will be Cocci, various types of bacilli, fusiform organisms, spirochetes, and in advanced periodontitis, amoebas and trichomonads.

The normal oral flora is so vast, however and is made up of so many varieties of microorganisms that it has never been possible to prove conclusively that any one type of microorganisms is of greater importance than others as far as periodontal diseases are conserved. The plaque associated with gingivitis and early periodontitis is complex. In the early stages of gingivitis the Actinomyces group of organisms is the dominant genus in the supragingival plaque.

Plaque or plaque derived endotoxins may act as irritants or antigens in both nonspecific acute inflammatory responses and immune mechanisms of defence. One of the prime functions of the immune response is to activate the inflammatory system.

Specific microorganisms sometimes cause an inflammatory reaction of the gingiva, although the clinical appearance may be entirely nonspecific.


Calculus, whether in a supragingival or subgingival position, causes irritation of the contracting gingival tissue. This irritation is probably caused by the byproduct’s of the microorganisms, although the mechanical friction resulting from the hard, rough surface of the calculus may play a role.

Food impaction and General Oral Neglect:-

The impaction of the food and accumulation of debris on the teeth because of oral neglect result in gingivitis through irritation of the gingiva by toxins of microorganisms growing in this medium. The degradation of food debris may also prove irritating to the gingival tissues.

Faulty or irritating Restorations or Appliances:-

Faulty restorations may act as irritants to gingival tissues and thereby induce gingivitis. Overhanging margins of proximal restorations may directly irritate the gingiva and in addition allow the collection of food debris and organisms that further injure these tissues. Improperly contoured restorations may also produce gingival irritation by causing food packing or abnormal excursions of food against the gingiva during mastication.

Mouth breathing:-

Drying of the oral mucous membrane because of breathing with the mouth open, because of an environment of excessive heat, or from excessive smoking, will result in gingival irritation, with accompanying inflammation or sometimes hyperplasia.

Tooth malposition:-

Teeth which have erupted or which have been moved out of physiologic occlusion, where they are repeatedly subjected to abnormal forces during mastication, are apparently very susceptible to the development of periodontal disease. Calculus may be deposited on the surface of malposed tooth; the bacteria present attack the tissue around this tooth.

Chemical or Drug application:-

Many drugs are potentially capable of inducing gingivitis, particularly an acute case of gingivitis, owing to a direct local or systemic irritating action. For example, phenol, silver nitrate, the volatile oils, or aspirin, if applied to the gingiva, will provoke an inflammatory reaction.

Nutritional Disturbances:-

Nutritional imbalance is frequently manifested in changes n gingiva and deeper underlying periodontitis. An adequate intake, absorption and utilisation of the various vitamins, minerals and other food stuffs are essential to the maintenance of a normal periodontitis.


The gingiva undergoes certain changes during pregnancy which have been termed

Pregnancy gingivitis. The appearance of the gingiva in the pregnant women varies from an unchanged to a smooth, shiny, deeply reddened gingiva with frequent focal enlargement and intense hyperaemia of the interdental papilla. Occasionally, a single tumour like mass will develop, the pregnancy tumour which is histologically identical with the pyogenic granuloma. Pregnancy induces a hypersensitive response to a mild injury which otherwise would have been innocuous. This gingivitis clinically nonspecific in appearance, may occur near the end of the first trimester and may regress or even completely disappear at the termination of the pregnancy.

Diabetes Mellitus:-

Diabetes has been repeatedly reported in association with severe periodontal disease, especially in younger people. It has not been proven that diabolical a specific cause of severe periodontal disease,  since many patients with diabetes have normal periodontal structures. However in uncontrolled diabetes, many metabolic processes are affected including those which make up resistance to infection or trauma. The effectiveness of the healing process is decreased possibly as a result of a disturbance i cellular carbohydrate metabolism. Therefore considering the periodontist located in the oral cavity with its many predisposing factors including calculus, bacteria and trauma, it is not surprise that this structure appears to be break down more readily in persons with uncontrolled diabetes than in normal people.

Other Endocrine Dysfunctions:-

Gingivitis is reported to occur with some frequency in puberty as the so called puberty gingivitis. The gingiva appears hyperaemic and edematous. The fact that many adolescents are chronic mouth breathers as a result of lymphoid hyperplasia of the tonsils and adenoids has suggested that the endocrine basis is relatively unimportant, while the mouth breathing being the actual cause of the condition.

Gingivitis associated with menstruation has been reported by many. In addition a nonspecific gingivitis with gingival bleeding, vicarious menstruation may occur sometimes. This phenomenon is rare.

Psychiatric Phenomena:-

Psychiatric disturbances appear to have a definite influence upon the severity of periodontal disease. The severity of periodontal disease significantly greater in psychiatric patients. The severity of periodontal disease increased significantly as the degree of anxiety increased. The severity of periodontal disease decreased significantly in both normal and psychiatric patients as the educational level of the patient increased.

What ere the symptoms of the Gingivitis?

The most common form of gingival disease is Chronic gingivitis. The clinical features of Chronic gingivitis are

  • Gingivitis may be localized or generalised. It sometimes involves only the marginal gingiva, known as marginal gingivitisor interdental papilla, papillary gingivitis.when hyperaemia and swelling of the marginal gingiva are confined to a localized area of the gingiva, the affected area sometimes assumes a crescent shape and has been termed a ‘traumatic crescent’
  • Slight alterations in colour of the free or marginal gingiva from a light to a deeper hue of pink, progressing to red or reddish blue as the hyperemia  and inflammatory infiltrate become more intense.
  • Bleeding from gingival sulcus following even mild irritation such as tooth brushing or probing is also an early feature of gingivitis.
  • Edema which invariably accompanies the inflammatory response as it causes a slight swelling of the gingiva and loss of stippling
  • Inflammatory swelling of interdental papillae often produces a somewhat bulbous appearance of these structures. This increase in the size of the gingiva favours the collection of more debris with increased bacteria accumulations which in turn induce more gingival irritation.
  • when there is marked enlargement due to edema and fibrosis as a result of chronic, the process is called hyperplasia gingivitis.
  • Pus from the gingival sulcus by pressure may occur in advanced Chronic gingivitis.

Radiological Features:-

Chronic gingivitis in which the inflammation is limited strictly to the gingiva, does not manifest changes in the underlying bone. When bony changes become evident, the condition is termed periodontitis.

What is the treatment for the Gingivitis?

Most cases of Chronic gingivitis are due to local irritation. If the irritants are removed at this stage, the inflammation with its attendant swelling due to hyperaemia, edema will disappear within a matter of hours or a few days, leaving no permanent damage.

  • Recovery usually follows the removal of the irritants.
  • Early treatment followed up by proper brushing of teeth and frequent prophylaxis.
  • Brush your teeth more effectively.Make sure you brush for 2 minutes, 2 times every day. Consider an electric toothbrush that will give you a more thorough cleaning than a manual brush. Pay special attention to the gum line, as that is where a lot of toxic plaque bacteria can build up, and a healthier mouth starts at the gums.
  • Dental scaling should be done to remove the calculus, plaque
  • Chemical plaque control methods such as using mouthwashes are recommended.
  • Floss daily. Flossing is a great tool for the treatment of gingivitis, as it removes food particles that can feed plaque that your toothbrush could miss.
  • If there is poor response to good local therapy, a search should be made for systemic factors, which might be complicating.

Dentigerous Cyst Symptoms, Treatment and Complications

A Dentigerous cyst also called as follicular cyst.Dentigerous cyst can be defined as an odontogenic cyst that surrounds the crown of an impacted tooth, caused by fluid accumulation between the reduced enamel epithelium and the enamel surface, resulting in a cyst in which the crown is located within the lumen.

This is one of the most common types of developmental odontogenic cyst. They form over the top of an unerupted tooth, or partially erupted tooth. The dentigerous cyst nearly always involves or in associated with the crown of a normal permanent tooth. This cyst is commonly associated with unerupted third molars, first and second premolars and canines. It is reported to be present more in males than in females. Dentigerous cyst may remain symptom less and may be diagnosed on routine radiographs or patients may give history of slowly enlarging swelling. Pain may be present only when they are secondarily infected.


  • This cyst is always associated initially with the crown of an impacted, embedded or unerupted tooth.
  • A dentigerous cyst may also be found enclosing a complex compound odontoma or involving a supernumerary tooth
  • The most common sites of this cyst are the mandibular and maxillary third molar and maxillary cuspid areas, since these are the most commonly impacted teeth
  • Most dentigerous cysts are solitary. Bilateral or multiple cysts are usually found in association with syndromes such as cleidocranial dysplasia and Maroteaux-Lamy syndrome.
  • Itis potentially capable of becoming an aggressive lesion.
  • Expansion of bone with subsequent facial asymmetry, extreme displacement of teeth, severe root resorption of adjacent teeth and pain are all possible sequelae brought about by continued enlargement of the cyst.
  • Custic involvement of an unerupted mandibular third molar may result in a hollowing out of the entire Ramos extending up to the coronoid process and condole as well as in expansion of the cortical plate due to the pressure exerted by the lesion.
  • In the case of a cyst associated with a maxillary cuspid, expansion of the anterior maxilla often occurs and may superficially resemble an acute sinusitis or cellulitis. There is usually no pain or discomfort associated with the cyst unless it becomes secondarily infected.
  • Dentigerous cyst

Radiological features:-

Radiographic examination of jaw involved by a dentigerous cyst will reveal a radiolucent area associated with an unerupted tooth crown. The impacted or unerupted tooth crown may be surrounded symmetrically by this radiolucency. A dentigerous cyst can be suspected when the follicular space is more than 5mm.

The dentigerous cyst is usually a smooth unilocular lesion but occasionally one with multilocular appearance may occur. In actuality, the various ompart ents are all united by the continuous cystic membrane. Sometimes the radiolucent area is surrounded by a thin sclerotic line representing bony reaction.

Three radiological variations of the dentigerous cyst may be observed.

  1. In the central variety, the crown is enveloped symmetrically. In these instances, pressure is applied to the crown of the tooth and may push it away from its direction of eruption. In this way, mandibular thrid molars may be found at the lower border of the mandible or in the ascending Remus and a maxillary canine may be forced into the maxillary sinus as far as the floor of the orbit.
  2. The lateral type of dentigerous cyst is a radio graphic appearance which results from the dilatation of the follicle on one aspect of the crown. This type is commonly seen when an impacted third molar is partially erupted so that it’s superi aspect is exposed.
  3. Circumferential dentigerous cyst results when the follicle expands in a manner in which the entire tooth appears to be envelopedby cyst.

Histologic Features:-

There are no characteristic microscopic features which can be used reliably to distinguish the dentigerous cyst from the other types of odontogenic cysts. It is usually composed of a thin connective tissue wall with a thin layer of stratified squamous epithelium lining the lumen.

Rete peg formation is generally absent except in case that are secondarily infected. Islands of odontogenic epithelium is seen. An additional finding, especially in cysts which exhibit inflammation, is the presence of Rushton Bodies within the lining epithelium.


The treatment of dentigerous cyst usually dictated by the size of the lesion. Smaller lesions can be surgically removed in their entirety with little difficultly. The larger cysts which involve serious loss of bone and thi the bone dangerously are often treated by insertion of a surgical drain or marsupilization. Such a procedure is often necessary because of the potential danger of fracturing the jaw if complete surgical removal wer attempted. Recurrence is relatively uncommon.


Several relatively serpotential complications exist stemming from the dentigerous cyst, besides simply the possibility of recurrence following incomplete surgical removal. These include

  • The development of an ameloblastoma either from the lining epithelium or from rests of odontogenic epitheliumin the wall of the cyst
  • The development of epidermoid carcinoma from the lining epithelium or odontogenic epithelium.
  • The development of a mucoepidermoid carcinoma, basically a malignant salivary gland tutor, from the lining epithelium of the dentigerous cyst.


What is Hyperplasia? Causes, Classification,Treatment

What is Hyperplasia? Causes,Symptoms and Treatment

Hyperplasia also called as Facial Hemihypertrophy. It is a rare developmental anomaly characterised by asymmetric overgrowth of one or more body parts. Hemihyperplasia can be an isolated finding, but it also may be associated with a variety of malformation syndromes.

Malformation syndromes associated with Hemihyperplasia

  • Beckwith-weidemann syndromes
  • Neurofibromatosis
  • Klippel-trenaunay-Weber syndrome
  • Epidermal nevus syndrome
  • Proteus syndrome
  • Segmental odontomaxillary dysplasia

Classification of Hemihyperplasia

  1. Complex Hemihyperplasia : it is the involvement of half of the body (at least one arm and one leg);affected parts may be contra lateral or ipsileral
  2. Simple Hemihyperplasia: is the involvement o a single limb
  3. Hemifacial hyperplasia: is the involvement of one side of the face


The cause is unknown, but the condition has been variously ascribed to vascular orlymphaticabnormalities; CNS disturbances and chromosomal abnormalities


Patients affected by this condition exhibit 

  • an enlargement which is confined to one side of the body
  • Unilateral macroglossia
  • Premature development and eruption 
  • An increased size of dentition 
  • Females are affected somewhat more frequently than males 

Oral symptoms 

  • Dentition is abnormal in three respects crown size, root size and shape, and rate of development.
  • This enlargement may involve any tooth, but seems to occur most frequently in thecuspids, premolars and first molar.
  • Permanent teeth on the affected side are often enlarged, although not exceeding 50% increase in size 
  • The roots of the teeth are sometimes proportionally enlarged but may be short
  • The permanent teeth on the affected side develop more rapidly and erupt before their counterparts on the uninvolved side
  • Premature shedding of the deciduous teeth
  • The bone of the maxilla and mandible is also enlarged, being wider and thicker, sometimes with an ulterior trabecular pattern 
  • The tongue is commonly involved by the hemihypertrophy and may show a bizarre picture of enlargement of lingual papillaein addition to the general unilateral enlargement and contra lateral displacement
  • The buccaneers mucosa frequently appears velvety and may seem to hang in soft,pendulous folds on the affected side

Treatment and Prognosis 

There is no specific treatment for this condition other than attempts at cosmetic repair. Cosmetic surgery is advised after cessation of growth. Periodic abdominal ultrasound is recommended to rule out tutors.

Differential Diagnosis:– There are certain diseases of the jaws,such as neurofibromatosis and fibrous dysplasia of the jaws, that may give the clinical appearance of facial hemihypertrophy, but these can usually be differentiated readily by the lack of effect on tooth size and rate of eruption.

Dental viva voice questions in Impression Materials

Impression materials Viva voice questions

  • what is syneresis?

fluid exuded from the impression seen as droplets on surface are called syneresis

  • What is imbibition?

Absorption of water by the impression when placed in water is called imbibition.

  • which impression shows least dimensional change upon disinfection?

Addition silicones have very little residual polymerization, making them the most dimensional you stable of all the dental materials. They are also highly biocompatible impression materials.

  • what is suspension?

Larger, visible, non-soluble particles in solvent. It exists as 2-phase system.

  • what is Emulsion?

Liquid droplets which are suspended in water.

  • Define colloids or Sols?

A solid, liquid, or a gaseous substance made up of large molecules or masses of small molecules that remain in suspension in a surrounding continuous medium of different matter.img_1337

  • what is Accelerator?

A compound that speeds up the reaction; also refers to the component called the catalyst in the reaction of impression materials.

  • what is Cast?

A dimensionally accurate reproduction of a part or parts of the oral cavity or extra oral facial structures produced in a durable hard material.

  • Define Addition reaction? 

A polymerisation reaction in which each polymer chain grows to a maximum length in sequence and no reaction byproduct is formed.

  • Define Condensation reaction?

A polymerisation process in which the polymer chains grow simultaneously and a reaction by-product is formed with associated shrinkage.

  • What is Cure? 

The reaction process that takes place primarily during the setting of a polymer but continues after setting.

  • Define Working time?

The total time from the start of mixing to the final time at which an impression tray can be fully seated without distortion.

  • Define Setting time?

The elapsed time from the star of mixing until the impression material becomes firm enough to resist permanent deformation .

  • what is permanent Deformation?

Irreversible change in shape that occurs when the polymer responds as a viscous liquid under an applied pressure.

  • what is pseudo plastic behaviour?

Characteristic of a material to become more fluid when an applied force is increased; this behaviour involves shear thinning and is strain rate dependent.

  • what is dashpot?

An element of the viscoeladtic model describing the viscous response of a polymer.

  • what are the ideal properties of an Impression material?
  1. They should be fluid enough to adapt to the oral tissue.
  2. they should be viscous enough to be contained in the tray that is seated in the mouth.
  3. while in the mouth, they should be transform into a rubbery or a rigid solid in a reasonable amount of time. Ideally the total Setting time should be less than 7 minutes
  4. The set impression should not distort or tear when removed from the mouth
  5. the impression should maintain itsdimensional stability after removal of a cast so that a second or third cast can be made from the same impression.
  6. The materials should be biocompatible
  7. The materials, associated processing equipment, and processing time should be cost-effective.

Periodontal pockets Classification, symptoms and Treatment

Periodontal pockets are caused by microorganism so and their products, which produces pathological tissue changes that lead to the depending of the gingival sulcus. Pocket formation starts as an inflammatory change in the connective tissue wall of the gingival sulcus.

Periodontal pocket

Classification of periodontal pockets

Gingival pocket

It is also known as pseudo pocket or relative pocket or false pocket. It is formed by gingival enlargement, without destruction of the underlying periodontal tissues. The sulcus is deepened because of the increased bulk of the gingiva.

Periodontal pocket

It is also known as absolute or true pocket. There is destruction of the supporting periodontal tissue; progressive pocket deepening leads to destruction of the supporting periodontal tissues and loosening and exfoliation of the teeth.

Supra bony pocket:

Also known as supracrestal or supra alveolar pocket. Bottom of the pocket is coronal to the underlying alveolar bone. Bone destruction pattern is horizontal.

Infrabony pocket:

Also known as subcrestal or intraalveolar pocket. Bottom  of the pocket is apical to the level of the adjacent alveolar bone. Bone destruction pattern is vertical.

classification based on tooth surfaces involved:

Simple pocket:

only one tooth surface involved

complex pocket:

involves more than one surface

compound or spiral pocket:

Originating on one tooth surface and twisting around the tooth to involve one or more additional surfaces.

Signs and symptoms

  • Gingival bleeding
  • Gingival suppurations
  • Tooth mobility
  • In some cases pus may be expressed by applying digital pressure.
  • Localised pain or deep pain in the bone.
  • There may be bluish red vertical zone from the gingival margin to the alveolar mucosa.

    How to manage periodontal pockets?

  • pocket irrigation- devices like squeeze bottles and blunt hypodermic needles can be used to irrigate the pocket with chemotherapeutic agents.
  • flap surgery to eliminate pockets.

Dental Materials Viva Voice Questions for 1st year BDS

Physical properties of Dental materials

dental viva

  1. What is the goal of the dentistry?

The goal of the dentistry is to maintain or improve the quality of life of the dental patients. This goal can be accomplished by preventing disease, relieving pain, improving mastication efficiency, enhancing speech and improving appearance.

  1. What are the dental materials used in dentistry?

The four groups of materials used in dentistry today are metals, ceramics, polymers and composites.

  1. What are the qualities of ideal restorative material?

An ideal restorative material would be

  • Be biocompatible
  • Bond permanently to tooth structure or bone
  • Match the natural appearance of tooth structure and other visible tissues
  • Exhibit properties similar to those of tooth enamel, dentin and other tissues
  • Be capable of initiating tissue repair or regeneration of missing or damaged tissues


  1. What is Acid-etching technique?

It is a process of roughening a solid surface by exposing it to an acid and thoroughly rinsing the residue to promote micromechanical bonding of an adhesive to the surface

  1. What is Adhesion?

When two substances are brought i9nto intimate contact each other, the molecules of one substance adhere or attracted to, molecules of the other substance. This force is called as adhesion. Adhesion may occur as a chemical or physical or a combination of both types

  1. What is Cohesion?

Force of molecular attraction between molecules or atoms of the same species.

  1. Define Coefficient of thermal expansion?

It is defined as the change in length per unit of the original length of a material when its temperature is raised 1 degree kelvin

  1. Define stress and what are the types of stresses?

Stress is defined as an internal force opposing an applied load.

Compressive stress:- internal resistance to a load that tends to compress or shorten a body

Tensile stress:– internal resistance to a load that tends to stretch or elongate a body

Shear stress:- a stress that tends to resist a twisting motion, or a sliding of one portion of a body over another is a shear or shearing stress

  1. What is strain?

Strain is defined as a deformation resulting from an applied load. Strain has no units to measure

  1. Define proportional limit?

It is defined as the maximum stress that can be induced without permanent deformation

  1. What is young’s modulus or modulus of elasticity?

Stress/strain ratio within the proportional limit is called elastic modulus or young’s modulus. It measures the relative rigidity or stiffness of material

  1. What are the different hardness tests?

Macro hardness tests:- Brinnel and Rockwell tests are classified as macro hardness tests and they are not suitable for brittle materials

Micro hardness tests:– the Knoop and Vickers tests are classified as micro hardness tests. Both of these tests employ loads less than 9.8 N

The SHORE and the BARCOL tests are used for measuring the hardness of rubbers and plastics

  1. What is Smear layer?

After the dentist has completed a tooth preparation for a filling, tenacious microscopic debris covers the enamel and dentin surfaces. This surface contamination, called the smear layer.

  1. What is Creep?

Time-dependent plastic strain of a material under a static load or constant stress

  1. Define Flow?

Flow is the deformation under a small static load even that associated with its own mass. Flow describes the behavior of amorphous material such as waxes.

  1. What is Hue?

Dominant color of an object

  1. What is Value?

Relative lightness of darkness of a color

  1. What is Chroma?

Degree of saturation of a particular hue

  1. Define Hardness?

The ability of a material to resist abrasion or wear

  1. What is Ductility?

Relative ability of a material to deform plastically under a tensile stress before it fractures

  1. What is Elastic modulus or Young’s modulus?

It is the ratio of elastic stress to elastic strain

  1. Define Plastic strain?

Deformation that is not recoverable when the externally applied force is removed

  1. Define Corrosion?

Chemical or electrochemical process in which a solid; usually a metal, is attacked by an environmental agent, resulting in partial or complete dissolution.

  1. What is Tarnish?

Surface discoloration on a metal, or as a slight loss or alteration of the surface finish or luster

  1. What is viscosity?

Resistance of a fluid to flow






Lasers in Conservative Dentistry and Endodontic



Conservative Dentistry:-

lasers in conservative dentistry

Cavity preparation:-




Tooth etching:-


Endodontic therapy:-


Disinfection of the root canal system:-

