Top 40 Dental Interview Questions & Answers

1) Explain what is dental caries?

Dental caries also known as cavity or tooth decay, which is caused due to bacterial infection. It causes the destruction of hard tissue of the teeth and results in demineralization of the teeth.

2) Explain what causes bleeding gum?

Bleeding gums are due to the buildup of plaque at the gum line. This condition is referred as gingivitis or inflamed gums.  If plaque is not treated it would harden into tartar, which leads to increased bleeding, and it would result in more adverse form of gum and jawbone disease known as periodontitis.

3) What other than gingivitis can cause gum bleeding?

  • Bleeding disorder
  • Brushing too hard
  • During pregnancy hormonal changes
  • Not flossing correctly
  • Leukemia
  • Scurvy
  • Blood thinners
  • Deficiency of vitamin K
  • Tooth or gum related infections
  • Inappropriate dentures or other dental appliances
  • Idiopathic thrombocytopenic purpura

4) Mention what are the symptoms of tooth infection?

Tooth infection symptoms are

  • Toothache
  • Having pain while chewing
  • Hot or Cold sensitivity of the teeth
  • Bitter taste in the mouth
  • Possible fever
  • Breath odor
  • Swollen glands of the neck
  • General discomfort, uneasiness and ill feeling
  • Upper or lower jaw area swollen

5) Explain what is root canal?
Root Canal is a treatment carried out in the patient having large cavities that damage the tooth root.  The root becomes inflamed and infected in this condition.

6) Explain step by step what is the procedure of root canal?

  • Step 1: First the dentist numbs the tooth by giving local anaesthetic.
  • Step 2: The opening is made through the crown of the tooth to the decay region or pulp chamber
  • Step 3: Then unhealthy tissues and infected cells are removed using special files
  • Step 4: Then shape the canal so that filling the material can be filled easily
  • Step 5: Canals are filled with a permanent material

7) Explain what are the instruments used for root canal?

For root canal, the instruments used are

  • Lentulo spiral filler or rotary paste filler
  • Finger spreader
  • Endodontic plugger
  • Gutta percha points
  • Obturating material sealers

8) Mention what is the ideal properties of endodontic sealer?

The ideal properties of endodontic sealer is

  • It should create a watertight seal
  • It should provide good adhesion with canal wall
  • It should be radiopaque ( Visualize on x-ray )
  • On setting it must not shrink
  • It should be bacteriostatic
  • It should set slowly and insoluble in tissue fluids
  • Soluble in the standard solvent
  • It should not stain tooth structure

9) Explain the term Crown, Enamel, Root and Dentin?

  • Crown: The top part of the tooth is referred as Crown, the shape of the crown determines tooth functions
  • Enamel: The outermost layer of tooth is referred as Enamel
  • Root: The bottom part of the tooth that is embedded in bone is referred as Root
  • Dentin: Dentin is the layer of the tooth, underneath enamel

10) What is pulp?

Pulp is the central tissue found in the center of all teeth, where blood vessels and all nerve tissues are found.

11) Explain what is trigeminal neuralgia?

Tooth ache is generally caused by dental disease due to infection, but there is some uncommon condition like trigeminal neuralgia that causes tooth ache.  Trigeminal nerve is one of the main nerves which originates from the brain stem and enter the face, and end in the tooth bottom. When this nerve gets disturbed or damage during an accident or while operation, it causes the pain known as trigeminal neuralgia. Such condition is most commonly found among the elderly people and those having hypertension.

12) Mention what are the two classes in which root canal material is classified?

Root material is classified into two classes

  • Orthograde
  • Retrograde

13) How Orthograde and Retrograde filling material is classified?


  • Solid: Silver cones, stainless steel
  • Semi-solid: Gutta percha
  • Pastes: ZnO, Resins
  • Combination of solid and semi-solid


  • Amalgam, GIC, Calcium phosphate cement, DBA, super EBA

14) Explain what is the role of fluoride in tooth?

  • Prevents de-mineralization: In bacterial infection, bacteria combines with sugar and produces acid that damages the outer covering of tooth or enamel and starts de-mineralization of tooth. Fluoride stop acid from damaging enamel.
  • Re-mineralization: If there is already some damage due to acid, fluoride will deposits in the demineralized areas and begins strengthening the enamel; a process called re-mineralization

15) Explain what is dental abscesses?

The accumulation of pus, dead tissue and other fluids due to a bacterial infection is known as dental abscesses.  It might either occur inside the pulp chamber or inside the gums.

16)  Explain what do you mean by air abrasion?

Air abrasion is the techniques used by dentist to clean the infected area and remove dead cells.  In this technique, fine particle stream is aimed at the tooth surface.  The particles are made up of silica, baking soda or aluminium oxide.  A compressed air or gas is used to generate the force to clear the dead cells and tissues.

17) How safe are dental X-rays?

Exposure to access amount of X-rays may cause cancer, however, controlled X-ray exposure are safe to use. With advanced digital X-ray machines which limits the radiation beam to a smaller area and for shorter period it makes even safer.

18) What does the term mean “abutment”?

“Abutment” is an implant fixture or tooth used as a support for prosthesis.

19) What is “Alveolar”?

Alveolar is used to refer a bone that is attached to the tooth.

20) Explain the term mandibular canal?

The passage that transmits vessels and nerves through the jaw to the branches that distributes them to the teeth

21) Explain what is the difference between Endodontics and Orthodontics?

  • Endodontics:  It is the branch of dentistry which deals with a physiology, morphology and pathology of the human dental pulp and periradicular tissues. It has restricted the diagnosis and treatment upto the pulp and periradicular tissues only. They are root canal specialists and are trained to do complex root canal surgeries.
  • Orthodontics:  This word comes from latin word that means “straight teeth.”  Orthodontics are specialized in clear aligner therapy, appliance therapy and in braces, which are used to straightened teeth.

22) Explain what Periodontics does?

Periodontics deals with the treatment and surgeries of gums, bones and connective tissues surrounding the teeth.

23) Explain what is the role of Dental Hygienist?
The role of dental hygienist includes
• Assisting dentist in the prevention and treatment of oral disease by monitoring the patient condition
• Scaling and polishing of teeth and gums using different types of dental tools
• Giving advice to the patient for maintaining their teeth

24) What would you suggest to a patient who wants to prevent tooth decay?
Tooth decay can be prevented in many ways like
• Brushing twice a day with floss.
• Maintenance of the gum margin
• Timely detection and prevention of gum disease
• Regular visit to a dental care facilities
• Teeth whitening and bleaching

25) Explain what is rubber cup polishing?
A rubber cup polishing is a tool that uses a polishing agent to remove the stain from the tooth surface by gently revolving it.

26) Explain what is a site-specific laser therapy and when it is required?
When bacteria had infected the gum to a greater extent, such that it had reached deep into the bones, then it becomes necessary to remove it with laser light. When infected area is exposed to laser light it penetrates through the gums and bones, and attacks the bacterial colony. This is known as site-specific laser therapy.

27) What are the tools required for performing laser therapy?
Tools required for laser therapy are
• Micro-ultrasonic laser
• Laser light
• Fine hand instruments

28) What is periodontal maintenance and what are the instruments used for it?
Periodontal maintenance is used to help maintain the result of treatment for periodontal disease. This specialized cleaning process is performed every 8, 10 or 12 weeks. The instruments that are used are micro-ultrasonic scale, fine hand instrument, polishing cup and paste and laser light.

29) What is site specific anti-biotic therapy?
To minimize the future growth of bacteria antibiotics are placed directly into the gum pockets.

30) Explain how Ultrasonic instrument works and what is it used for?
Ultrasonic instrument is used for removing plaque or tartar. The instrument uses tickling vibrations to knock larger pieces of tartar loose, and it also sprays a cooling mist of water while it works to wash away debris. It emits a high-pitched whistling sound.

31) On what basis does hygienist decide whether patient should go for Scaling and Rootcanaling?
• Hygienist will first look out for the plaque buildup and checks for the possible periodontal problems
• It will check for sulcus, it is the depth of the spaces between your gum and teeth with a special device known as periodontal probe
• Healthy tooth and gum have sulcus gap of about 3mm anything more than that may be due to dense plaque formation
• And based on the severity of the infection, scaling and root canaling is done

32) Explain what is a rubber dam and their advantages?
Rubber dam is a rectangular latex sheet, which is used to cover the area of the mouth except the tooth that is treated. It is used while performing root canal and tooth surgery.

• It prevents bacteria present in saliva to spread out to your tooth
• You don’t get water into your throat
• It helps to keep the tooth dry
• It protects lips, cheeks, and internal part of the mouth while performing surgery
• You can relax your tongue instead of continuously adjusting during surgery
• It protects the throat from possible tooth debris

33) List out different types of filling used?
• Amalgam
• Glass Ionomer
• Composite Resin
• Cast Gold
• Ceramics

34) What is “galvanic shock”?
Galvanic shock is referred to an electrical shock that you might experience in your mouth if you had amalgam filling adjacent to gold filling. The electric current generates due to the interaction of two different metals. So, it is better not to have gold and amalgam filling adjacent to each other.

35) When is glass ionomer filling is used?
Glass ionomer fillings directly form a chemical bondage with the tooth, due to which it takes minimum time for its formation. But this type of filling is relatively weak, and it is applied to soft surfaces or non-biting surface of the tooth like necks of the teeth or baby teeth. One benefit of this filling is that it releases fluoride from it that fights tooth decay.

36) What one should do if he/she knocks off the tooth out?
• Put the tooth straight into a cup of milk if it is completely ripped off, if not then let be in the mouth
• Do not pull out manually with force or jerks otherwise it may damage the ligaments, which are required if tooth has to be replaced
• Take painkillers if the pain is unbearable
• Don’t use clove oil or aspirin on the wound
• Visit a dentist or hospital without being getting panic
• Do not clean the tooth with disinfectant or let it dry out

37) Explain what is the difference between scaling and root planing?
Root Planing: Root planing is the technique of smoothening the root surfaces and removing any infected tooth structure.
Scaling: It is the process of removing dental tartar from the surfaces of the teeth

38) Explain what is the use of “Air Abrasion”?
Air abrasion can be used as
• Tooth Whitening
• While preparing a tooth for a filling, and act as a dreaded drill

39) What is the benefit of dental bridge and what are the types of dental bridges?
Dental bridge is a replacement for missing teeth; it protects from bone loss and disfiguration of facial structure too.

Types of bridges are

• Bounded or Maryland bridge
• Traditional bridge
• Cantilever bridge

40) On what occasion dental crown is suggested?
• To protect a fragile tooth from fracturing
• To restore a fractured tooth
• To attach a bridge
• To replace a large filling when there is not enough tooth remaining
• To cover a discolored or irregular shape tooth
• To cover a tooth that have gone under root canal treatment
• To cover dental implant

41) Explain how dental sealants are placed?
• First the tooth surface is cleaned thoroughly
• After that tooth are washed with water and dry out
• Next, acidic solution is applied on the fissure area of the tooth chewing surface for a few seconds and then rinsed off
• It creates a rough surface which enables dental sealant to stick the tooth surface firmly
• After the sealant are hardened by a light or by using the two-component dental sealant

42) List out the tools that are used by dental hygienist?
• Hand Scalers
• Curettes
• Ultrasonic Scaler
• Rubber cup polisher
• Floss
• Saliva ejector
• Air and water syringe
• X-ray Sensor
• Intraoral Camera

About the author

    Dorothy Gusmus

    Hi, I am Dorothy Gusmus. Chief editor at HealthUnify.