Dental Caries: Facts You Should Know About Causative Bacteria

Some 200 to 300 species of bacteria, yeast, and even protozoa harbor the human oral cavity.

The metabolic activity of the complex community of the bacteria determines the presence or absence of the disease of the hard and soft issues of the human oral cavity.

It is very difficult to assess and say that a particular species of bacteria causes diseases of the oral cavity, but it has become very clear that a relatively small group of bacteria is primarily responsible for the two major oral diseases: dental  caries and periodontal disease.

There are two bacteria that are associated with the development of dental caries in humans.  They are:

  • Streptococcus mutans
  • Lactobacilli

Facts about cariogenic* bacteria:

  1. These two bacteria can produce huge amount of acid (acidogenic).
  2. They are tolerant of acidic environment (aciduric)
  3. They are vigorously stimulated by sucrose.


Streptococci are very strongly associated with the onset of caries whereas Lactobacilli are associated with the active progression of the cavitated lesions.

*The organisms that cause caries are known as “cariogenic”.

The degree to which a tooth is likely to become carious is described as its “cariogenicity potential”.


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ADC Examinations-Frequently Asked Questions

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Q. I need to send a document to the ADC. Which address should I use?

A. This depends on whether you are using the postal service or a courier.

If you are posting a document, please address to:

PO Box 13278, Law Courts,  Vic  8010, Australia

If you are using a local or international courier to deliver a document, please address to:

 Level 2, 99 King Street, Melbourne,  Vic  3000, Australia

Applying for an Initial Assessment

Q. Do I need to provide details of my secondary education.

A. You are only required to provide evidence of your secondary (high school) education if you undertook your secondary education in Australia, New Zealand, Canada, UK, USA, Republic of Ireland or South Africa. If you did not undertake your secondary education in one of these countries then you are not required to provide this information and you do not need to complete questions 16-19 on the Initial Assessment Application form.

Q. When should I arrange for my Certificate of Good Standing to be sent to the ADC?

A. You should arrange for your Certificate of Good Standing to be sent to the ADC when you are completing your application for Initial Assessment. When your Certificate of Good Standing is received by the ADC it will be held securely and then matched to your application.

Q. What is the closing date for Initial Assessment applications? I would like to sit the next Written Examination.

A. Whilst there is no closing date for Initial Assessment applications we suggest that you submit your Initial Assessment application at least 12 weeks before the Written Examination closing date.

Applying for an examination

Q. How many attempts can be made at the Examination?

A. There are currently no restrictions on the number of attempts for either the Written Examination or the Practical Examination. However, you must pass the Practical Examination within 3 years of a successfully passing the Written Examination, otherwise you will need to re-sit the Written Examination.

Q. I have a place booked in an upcoming Written Examination but I have recently changed my contact details. What should I do?

A. You must arrange for redirection of mail (postal and/or email) if you change your address after the closing date for a Written Examination.

If the closing date has not passed, please submit a Change of Contact Details form to the ADC as soon as possible. If the form will not reach the ADC prior to the examination closing date, you must arrange for redirection of mail.

Withdrawing from an examination

Q. Can I withdraw from an examination?

A. Yes. A signed written letter must be sent directly to the Australian Dental Council by post advising us of your withdrawal.

Once received, your withdrawal will be processed and if applicable, a partial refund will be returned to you. Please allow up to seven (7) days for money to be refunded to your credit card.

For further information regarding withdrawal and examination fee refunds please refer to the Written Examination Handbook and the Practical Examination Handbook.

Q. If I withdraw from an examination can I transfer to a following examination?

A. No. You are NOT able to automatically transfer from one examination to another.

If you choose to withdraw from an examination, you are required to re-apply.

Examination fees and application forms are also NOT transferable between examinations.

You must complete a new examination application form, provide the required documentation and pay the required fee for each examination you apply to sit.

Can I change my venue for the Written Examination?

A. Yes. You may change your venue at anytime up to the close of the examination booking period via the Pearson VUE website. You do not need to notify the ADC of a venue change.

Q. I have a place booked in the next Practical Examination, but I can’t get my visa for travel to Australia in time. Can I transfer to the next Practical Examination instead?

A. No. Failure to undertake an examination because of inability to obtain necessary visas will be treated as a withdrawal and fees will be forfeited.

Sitting the Written Examination

Q. What happens if I am late for my examination?

A. You should arrive at the examination 30 minutes prior to the arrival time stated on your advice letter. You will NOT be admitted to the examination if you arrive at the venue after the start time and you will automatically receive a FAIL grade for that paper regardless of the reason for your late arrival.

Sitting the Practical Examination

Q. Do I need to provide my own protective eyewear?

A. Yes. All candidates must bring suitable eye protection. We will not provide this for you. You may bring magnifying loupes if you wish. The venue will provide you with a protective gown and disposable masks and gloves.

Q. Can I bring my own instruments to the examination?

A. No. The venues will provide the necessary standard equipment needed. You may not bring instruments or handpieces. You must, however, bring your own burs.

Q. Do my burs need to be sterile?

A. All burs brought to the examination must be clean with NO visible soiling, but they do not have to be sterile.

Q. Can I bring my own materials to the examination?

A. The venue will provide the standard necessary materials needed to complete the examination. You may, however, bring your own materials. Please be aware that if your materials require specialised equipment for dispensing, mixing etc., that equipment may not be available at the venue and you may not bring that equipment with you.

Q. What is the difference between materials and equipment?

A. Materials are generally items that are consumables.

Items regarded as materials include:

  1. Restorative materials (e.g. composite resins)
  2. Impression materials
  3. Rubber dam sheets
  4. Polishing discs (but not mandrels)
  5. Wedges
  6. Face shields

Items regarded as equipment included:

  1.  Handpieces
  2. Hand instruments (e.g. probes, mirrors, enamel hatchets)
  3. Matrix bands and holders
  4. Rubber dam clamps and forceps
  5. Rubber dam frames
  6. X-ray film holders
  7. Dispensing guns
  8. Scalpels and blades
  9. Amalgamators
  10. Non-dental headlamps
  11. Hand-held magnifying glasses

Getting my results

Q. How long will it take to receive my results?

A. Examination results are usually issued 6 weeks after an examination.

Candidates should not contact the ADC before this time. All results for the Written Examination and Practical Examination will now be available to dentistry candidates online via the ADC Candidate Portal. Dental Hygiene and/or Dental Therapy candidates cannot access the Candidate Portal and will receive their results via email.

Q. I have just sat my first Written Examination. When I try to log onto the Candidate Portal I get a message saying that I have provided an invalid username. What should I do?

A. As a new user, the Candidate Portal won’t recognise your username until the Written Examination results have been released. Try again later. Remember that examination results are usually released 6 weeks after the Written Examination.

Q. I failed my recent examination. Can I get more feedback on my performance?

A. The ADC does provide feedback in the form of the candidate Results Profile which is given to you with your results. However, the ADC does not provide more detailed post-examination feedback to candidates.

(updated 1 August 2018)

ADC – Dates of Examinations

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Written Examinations

FOR Dentist

Examination, application opening and closing dates for 2018:

2018 Written Examinations will be held on

September 2018 dentist written examination application period

Applications for the 10 to 11 September 2018 written examination will be accepted between 21 May and 8 June 2018.

Practical Examinations

FOR Dentist

Practical Examination dates 2018:

The ADC will hold the first Practical examination for 2018 on 23-25 March 2018.

This examination will be held at the following venues:

  • Griffith University – Gold Coast Campus
  • Royal Dental Hospital of Melbourne
  • Westmead Centre for Oral Health – Sydney
  • James Cook University – Cairns
  • Oral Health Centre of Western Australia - Perth

You are eligible to apply for this examination if:

  • You had applied for, but were not offered, a place in 2017 due to limited places.
  • You passed the Written Examination in February 2017

If eligible, you should apply by submitting a Practical Examination application form during the published application period.

If you are not eligible to apply for this examination please keep checking our website for more information regarding Practical Examination delivery for the rest of 2018.

Application periods for 2018 Practical Examinations:

You may submit a Practical Examination form during an application period. There will be two application periods for candidates wishing to apply for a Practical Examination place in 2017. You may apply during either application periods as long as you are eligible to sit the Practical Examination. You may nominate your preferred session on your application form; however you must hold a valid written examination for the examination session you nominate. Please visit the Applying for the Practical Examination page for more information on how to apply for a practical examination.

Eligibility of written examination

Your written examination validity last for three years, and must be valid at the closing date for the examination for which you are applying. Please note that, for eligibility purposes, the closing date differs from the end of the application period.

The closing dates for 2018 Practical Examinations are listed below:

7-9 April 2017 and 30 June 2017 - 2 July 2017  For eligibility purposes, the closing date for these examinations is 5 May 2017. Your written examination must be valid at this date if you wish to apply for either of these examinations.

24-26 November 2017 For eligibility purposes, the closing date for this examination is 27 October 2017. Your written examination must be valid at this date if you wish to apply for this examination.

ADC Examinations: General Information

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The candidates desirous of appearing the ADC Examination process have to go through the following process:


After the initial assessment of qualifications, candidates must undertake both a Written Examination and a Practical Examination.

The Written Examination is held twice each year in March and September, and the Practical Examination is held twice each year in June and November. Candidates must successfully complete the Written Examination prior to sitting the Practical Examination.


Written Examination

The Australian Dental Council’s Written Examination is designed to test your knowledge of the science and practice of dentistry and to assess clinical judgement and reasoning skills relevant to dental practice in Australia.

Each Written Examination session is held over two full consecutive days and two sessions are held each year, during the first half of March and September. The examination is computer-delivered and is offered in multiple locations within Australia and overseas.

The Written Examination consists of four papers containing both scenario-based and single-best answer Multiple Choice Questions (MCQ). Each examination consists of a different set of questions, however the standard required for a pass in each examination is the same. The four papers must be completed in one examination session, i.e. it is not possible to sit one of the papers in March (or September) and the remaining paper/s in September (or March).

Examination format

The Written Examination is held twice a year, over two full consecutive days, and consists of four 2-hour examination papers. Each paper consists of 80 scenario-based multiple-choice and single-best answer multiple-choice questions. All four papers must be completed in one examination session.


Paper 1

  1. Tooth Conservation
  2. Dental Caries
  3. Endodontics
  4. Dental Pulp
  5. Dental materials

Paper 2

  1. Fixed Prosthodontics
  2. Removable Prosthodontics
  3. Implantology

Paper 3

  1. Anaesthesia and Resuscitation
  2. Infection Control
  3. Medicine and Surgery
  4. Oral Maxillofacial Surgery
  5. Oral Medicine
  6. Oral Pathology
  7. Pharmacology and Therapeutics

Paper 4

  1. Orthodontics
  2. Paediatric Dentistry
  3. Periodontics
  4. Preventive Dentistry
  5. Public Dental Health
  6. Radiology

Continue reading "ADC Examinations: General Information"

Root Canal Treatment – RCT

Root canal treatment (RCT) is the treatment of the canal of a tooth. It is done once a tooth's pulpal vitality is in doubt or it has died. It is done to prevent the further progression of the disease to the peri-apical area, for example, peri-apical granuloma, cyst, or abscess.

Give few examples of the cases where RCT should be done

RCT will be done in the following situations:

After trauma to a tooth:

Suppose a person got a blow to the tooth in a road traffic accident. He/she did not have any problem during or within few days after the accident. But after 3-4 weeks, the tooth concerned started changing its color. From white, it became slight brown and then slowly gray to black.

It is a sign of pulp death that happened due to past trauma.

fractured tooth
Traumatic fracture of an upper front tooth.

At the time of accident, the arteries supplying the blood to the tooth got damaged and the tooth stopped getting it nutrients and slowly died. The dead pulp started releasing certain colors that resulted in the color change of that tooth.


Dental Caries:

A person that had carious tooth did not get proper treatment in time and the caries reached the pulp. Once it reached the pulp, it caused the pulp to die. The death of the pulp will cause pain in the advance stage.

dental caries
Advance stage of dental caries in upper first molar.

In both the above examples, the treatment will be root canal treatment.

But, doing a successful RCT depends on several factors, that only a dentist can decide. Un-necessary RCT is only a wastage of time and money. If in doubt, instead of going for RCT, the best treatment is to remove the tooth and get an artificial replacement.

Periodontitis or Periodontal Infection

Pulp of a tooth may get infected from the periodontal infection. The result will be same as of caries. The treatment involves not only RCT but necessitate the periodontal therapy for a complete success.


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Steps of the Root Canal Therapy

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The steps that should be followed while doing a RCT are given below:

  1. Access cavity preparation
  2. Canal identification
  3. Checking of canal’s patency
  4. Bio-mechanical preparation
  5. Creating an aseptic canal
  6. Obturation
A grossly decayed molar tooth needing RCT.

Access cavity preparation:

Access to the pulp chamber where pulp resides is gained through a properly designed access cavity. The design of the access cavity differs in every individual tooth.

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A properly prepared access cavity with straight line access to root canals in a maxillary first premolar tooth


Canal identification

A properly created access cavity gives direct access to the opening of the canal located on the floor of the pulp chamber. A dentist knows about the number of canals that normally are present in a particular tooth. But one should always be ready to look for additional canals.


Checking the patency of the root canals

After completion of the access cavity in a tooth the first step of the root canal treatment is to check the patency of the canal.  For this purpose, an endodontic explorer is used. The endodontic Explorer and is inserted in his canal up to the tip of the root. Once the endodontic Explorer has reached the effect of the roots, the biomechanical preparation should begin.


Biomechanical preparation of root canals

The first file that should be used in the biomechanical preparation of root canal should be the thinnest one that is of the size of the number 8 or 10. Subsequently the size of the file can be increased up to the desired thickness.


Obturation of root canals

Last step of Root Canal Therapy in the obturation of the canals. The canals are filled with an inert material up to the apex hermetically.  The access cavity is filled with a suitable filling material.  If indicated, a crown must be provided over a root canal treated tooth.


Abrasion of the Teeth

Types, clinical features, Causes and its prevention

Non-carious loss of the tooth structure is a problem that is

often found in senior citizens and is a cause of many complaints.

It is not a new entity but has acquired more attention in recent time.


Types of tooth wear

  1. Abrasion
  2. Attrition
  3. Erosion
  4. Demastication
  5. Abfraction


It is loss of tooth substance by the friction with a second object in the presence of an abrasive material.

The cavity formed due to abrasion are smooth and usually C shaped; more wider than deeper.


Clinical Features

These are usually facio-cervical concavities that are more broad than deep and can be associated with an abrasive diet. They are usually found on prominent teeth in the arch (i.e., canines, premolars, and mesio-buccal aspects of the first molars).

They may affect several teeth in a row with a “band” of abrasive damage.

Sometime they may cause increased hypersensitivity.

Figure 1. Cervical abrasion: note the concave smooth cavities in the cervical regions of upper and lower teeth.
Figure 1. Cervical abrasion: note the concave smooth cavities in the cervical regions of upper and lower teeth.

Causes of Abrasion

It is mostly located in the cervical area of the teeth. The reason may be one or a combination of following factors:

  1. Excessive tooth brushing for longer period
  2. Use of hard tooth brush
  3. Use of tooth paste containing highly abrasive material
  4. Use of locally prepared tooth cleaning powder or paste like Gul, Gulak or Lal Manjan (in India)
  5. Repeatedly putting foreign objects in the mouth like pipe smoking, pen, bobby pins and any other occupational material.

Prevention of Abrasion

Use of common sense is the best way of preventing the abrasion.

If the cause is a hard tooth brush or brushing of the teeth for a longer duration or use of an excessively abrasive tooth paste, then correcting the hardness of the tooth brush, adjusting the duration of brushing, and changing the tooth paste will be sufficient.

If the cause is abrasive food or any occupational factor, this may be difficult to treat but not impossible.


Treatment of Abrasion of the teeth




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