National medical university of LVIV department of therapeutic dentistry



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The cutting instruments|tool| for preparing of the carious cavities include the hand|manual| (enamel knife, power-shovel) and machine (drills) instruments.


Depending on the material|fabric| drills are divided|: steel, carbid, diamond. Drills produced for ordinary|usual| (direct and angular) and turbine handpieces.

The drill consists of bar|, neck and head.

As to their form they are divided into: spherical, fissure|, cone-shaped, wheel-shaped|, (with a shallow|small| notch), polirs (without notches).

The size|dimension| of the drills is fixed in figures is. Diameter ¹1=0,85 mm| ¹3=1,1 mm| ¹5=1,6 mm| ¹7=2 mm| ¹13=3,1 mm. Length of a drill for direct handpiece 44 mm|, angular – 17, 22, 27 mm. Dental drills 17 mm| in length are used in practice of child's dentistry and in the treatment of wisdom teeth |.

The form|shape| of the working surface of the drills predetermines their function. The round drill serves to open the carious cavity|, to remove the softened dentine, to open the pulp chamber,to enlarge the openings of root canals. Cone drills are used to form the shape of cavity|. The wheel-shaped drills are used for making retentional points|station|.

Sterilization (from Fr. Sterilisation, from лат. Sterilis - sterile) is a complete destruction or elimination of all living microorganisms, accomplished by physical methods.


Disinfection (from France. Desinfectio)  freeing from infectious agents.

Asepsis  is the system of prophylactic measures, directed on preventing of penetrating of microorganisms in a wound, organs and tissues of a patient, in the process of any medical measures. Asepsis includes: sterilization of instruments, materials, devices; special treatment of hands of a doctor; following the set of rules during the process of treatment; realization of the special hygienic and organizational measures in medical establishment.

Antisepsis  is the system of measures, directed to eliminate microorganisms in a wound. It must adhere to principles of antisepsis, because, working in the oral cavity the dentist always deals with the infected wound. The prophylaxis of contact infection consists in sterilization of all devices and instruments, a patient is in touch with. To follow strictly the rules of treatment of hands of a doctor is very important.

Sterilization is carried out by the use|utillizing| of physical factors and chemical matters. As to the physical factors they are as follows: high temperature, ultraviolet rays|beam|, ultrasound. The chemical methods include the use of alcohol, iodine, chloraminum, etc. The important condition of application of chemical facilities is|appear| bactericidal action, absence of the destructive action|act| on material|fabric| or instrument|tool|.

The physical methods of sterilizations are the following: steam, methods of infra-red irradiation, radiation and ultrasonic methods, hot air. Chemical methods include|switch| gas and sterilization of preparations by chemical solutions. The choice of method of sterilization is determined by features and properties|virtue| of subjected material|fabric|.

According to the standard, treatment of tools is carried out in three stages: disinfection|, previous sterilization cleaning and sterilization.



Control questions to|by| practical lesson |fabric|





  1. What value|importance| does the effective sterilization of dental instruments have?

  2. What diseases may be prevented if the dentist uses high-quality|quality| and sterile tools?

  3. How is the treatment of dental instruments carried out?

  4. What instruments|tool| are sterilized by the method of cold sterilization and why?

  5. What methods are used to sterilize handpieces?

  6. What is „sterilization”?

  7. Explain the meaning|importance| of the term of „disinfection|”.

  8. What is asepsis?

  9. What is antisepsis|?

  10. What types of sterilization are employed in dentistry?

  11. Name|call| the solutions which|what| are utillized|use| for cold sterilization.

  12. What is sterilized by the steam|couple| under pressure?

  13. Enumerate|enumerate| the physical methods of sterilization.


Situation tasks and test control
1. One of instruments|tool| used|what| more frequent by in the process of treatment of the teeth is|appear| smoother|. Name the stage of filling the carious cavities in which this instrument is not used?

    1. Bringing|payment| the material|fabric| into a cavity

    2. Design of a filling

    3. Mixing up the stopping material|fabric|

    4. Bringing|payment| of material|fabric| is for an insulating base

    5. It’s quite possible to execute|implement| all the above-mentioned


2. Choose the drill for forming the enamel edge|place| during cavitation on the masticatory surface of a 36th tooth:

  1. Cylindrical diamond

  2. Spherical hand-alloy|

  3. Spherical diamond

  4. Cone-shaped hand-alloy

  5. Inverted cone-shaped diamond


3. You are to perform the cavitation of carious cavity of medium sizes|dimension| on the masticatory surface of molar|. Choose the drill for forming its bottom.

  1. Spherical steel

  2. Inverted cone-shaped

  3. Cylindrical diamond

  4. Spherical steel

  5. Inverted cone-shaped hand-alloy |


4. You are to prepare the instruments|tool| for cavity preparation of the 3rd class. Among the offered tools there are several drills with the marking rings of different|diverse| colors. Choose the diamond drill with coarse|:

  1. Black

  2. Red

  3. White

  4. Dark blue

  5. Green


5. You are performing the cavity preparation on the masticatory surface of the 47th with a moderate caries. Choose the drill for forming its bottom:

  1. Spherical steel

  2. Inverted cone-shaped, hand-alloy |

  3. Inverted cone-shaped steel

  4. Cylindrical diamond

  5. Spherical steel


6. You have performed the cavity preparation concerning a moderate caries. In accordance with|according to| recommendations of the sanitary and antiepidemic organization the drills which have been used are to under go three stages of treatment (cleansing). What must be the first stage?

  1. Rinse|gargle| with the distilled water

  2. Wetting in washing solution

  3. Disinfection

  4. Washing in running water

  5. Sterilization by a thermal method


7. You conduct drilling of the carious cavity on the proximal surface of the 36th tooth according to general principles. Choose the cone-shaped drill to form the bottom of the carious cavity:

  1. Spherical diamond

  2. Inverted cone carbid|

  3. Spherical carbid|

  4. Cylindrical carbid|

  5. Inverted cone-shaped steel


8. The carbid cone-shaped drill it compared with the steel possess greater wearproofness, cutting ability|power|, heat-resistance. What material|fabric| is the most suitable for their making?

  1. Carbido-tungsten

  2. Instrumental steel with coating of nitride of titanium

  3. Alloy ed steel

  4. Chromonickel steel

  5. Titanic alloys


9. During the first practical lesson|occupation| on drilling the carious cavities a student fails to fix the drill|attempt| in the mechanical|mechanics| handpiecce for cone-shaped handpiece. Specify the difference in drills for various handpieces|diver?

  1. By material|fabric| of a working part|portion|

  2. By the form|shape| of a working part|portion|

  3. By material|fabric| of end|

  4. By the diameter of a working part|portion|

  5. By the diameter of end


10. While examining the patient it is necessary to define the consistency of dentine on the botton of the carious cavity which|what| is diagnosed in the 36th tooth. Specify|indicate| the instrument|tool|, that allows to define the degree of softening influence of dentine.

  1. Dental mirror

  2. Angual dental probe

  3. Excavator

  4. Dental pliers

  5. Dental probe


11. You are to assist the doctor|physician|, who|what| proceeds to prepare the carious cavity on the masticatory surface of the 46th tooth. Choose the instrument|tool| for conducting the first stage of preparing the cavity:

  1. Conical drills

  2. Excavator

  3. Diamond cylindrical drill

  4. Inverted-conical, hand-alloy dental drill

  5. Spherical hand-alloy dental drill


12. During the practical training you help a doctor|physician| who|what| prepares a carious cavity in fissure| of the masticatory surface of the 16th tooth. Choose the instrument|tool| for conducting the second stage of preparing.

  1. Excavator

  2. Inverted-conical, hand-alloy dental drill

  3. Cylindrical diamond dental drill

  4. Hand-alloy cylindrical dental drill

  5. Ail to choose


13. You are to perform the dental caries preparation on the medial surface of the 12th tooth at close contact between the teeth. Choose the most rational instrument|tool| for the first stage of preparing.

  1. Cylindrical diamond dental drill

  2. Spherical steel dental drill

  3. Inverted-conical steel dental drill

  4. Spherical hand-alloy dental drill

  5. Enamel knife


14. While preparing the carious cavity which is located on to medio-distal surface of the 22nd tooth, we preceed to the formation of its shape. What instruments|tool| are the most suitable for it?

  1. Enamel knife

  2. Cylindrical conical dental drill

  3. Inverted-conical dental drill

  4. Spherical dental drill

  5. Wheel-shaped dental drill


15. Compliting the previous|preliminary| stages of preparing the carious cavity on a proximal surface, we preceed to the formation of its shape. Choose the instrument|tool| for forming the gingival wall.

  1. Spherical dental drill

  2. Excavator

  3. Enamel knife

  4. Inverted-conical dental drill

  5. Conical dental drill


16. You instruct the nurse of the dentistry office as to the methods of sterilization of dental instruments. Specify|indicate| the time for sterilization of the dental drill by dry-air method:

  1. 120оС  40 min.

  2. 180оС  40 min.

  3. 140оС  30 min.

  4. 100оС  30 min.

  5. 200оС  40 min.



17. What method of disinfection of the dental handpieces will you choose, if in the directions as to its use|direction| there is no special instruction|utillizing|?

  1. A cold method of sterilization by|by means of| means of certificated sterilizers

  2. Ultraviolet boxing

  3. Cleaning|clearing| in the ultrasonic bath

  4. Boiling in a sterilizer at 100оС  45 min.

  5. Dry-air method



Reference literature


  1. Nikolyshyn a.K. Therapeutic dentistry /A.K. Nikolyshyn: a textbook is for the students of dental faculties of higher medical educational establishments of IV level of accreditation in two volumes, T.I.– Poltava: Divosvit, 2005.– 392 p.

  2. Borovskiy E.V. Therapeutic dentistry: a textbook is for the students of dental faculties of higher medical educational establishments.– M.: Med. Inform. agency, 2006.– 840 p.

  3. Nikolyshyn a.K. Therapeutic dentistry /A.K. Nikolyshyn: a textbook is for the students of dentistry faculties of higher medical educational establishments of IV level of accreditation in two volumes, T.IІ.–Poltava: Divosvit, 2007.– 280 p.

  4. Preclinical course of therapeutic dentistry: course of lectures|fabric| /L.O. Tsvykh, O.A. Petryshyn, V.V. Kononenko, M.V. Hysyk.– Lviv, 2002.–159 p.

  5. The methodological manual for|by| practical of therapeutic dentistry /L.O.Tsvykh, O.A. Petryshyn, V.V. Kononenko, M.V. Hysyk.– Lviv, 2003.– 98 p.

Practical lesson|occupation| №12
Theme: Ways of spreading the cariosity in hard tissues of a tooth and on various surfaces.

Short description of a theme
Ways of spreading the cariosity in hard tissues of a tooth and on its|its| various|diverse| surfaces possess its own peculiarities.

Thus the teeth of the upper|top| jaw are affected by the caries more often than the lower ones|. Obviously, it is quite possible that due to the active motions|movement| of the lower|bottom| jaw the teeth are supplied with blood in full measure|, and are cleaned more effectively from the food debris|food|.

The first molars are affected more frequently. This accounts for that the first molars are the first to erupt, and take the greatest load within the period of formation of permanent occlusion. As to the frequency of origin of pathological processes, the second molars gain the second place, while|gain the second placesssss the premolars| and upper|top| incisors – the third place, on fourth place are canines|fang|. The frontal teeth of the lower|bottom| jaw are affected by dental caries rarely|seldom|.

The certain|definite| conformity is in the localization of carious cavities. Thus, in the molars| the pathological process begins more frequently on the proximal, on the occlusive areas of fissures or proximal| surfaces. In premolars| and incisors – on proximal surfaces|, in canines – on the vestibular surfaces of necks. The tongue areas of teeth are affected by caries very rarely|seldom|.

In non-vital teeth a pathological process arises extremely|completely| rarely|seldom|, but, if it happens, it is the vestibular surface in the area of necks.

The caries of tooth is characterized|describe| by the damage of one or some|a little| types of tissues of tooth. But, if one hard tissue is affected, than it should be remembered that the whole tooth will be involved by the pathological process|all in all|, because all its|its| structures are in permanent|constant| anatomical-functional connection|truss|.

Due to the curvature of surface of a crown of the tooth, uneven thickness of the enamel and other factors, the spread of dental caries is determined by the site of its appearance. A caries in the enamel of masticatory surface develops deeply in the form|shape| of a triangle with an apex in the point of origin. As a result the tooth decay on a surface remains unnoticeable for a long time, while|where as| the damage of the deep tissues is deep enough.

In a dentine due to a greater content of organic substances as compared with enamel, a caries spreads|widens| more rapidly not only in a depth but also in the sides, especially|in particular case| in the area of enamel-dentine junction|compound|. This leads to the undermined edges|place| of the enamel, which is not supported by the dentine. The spread of caries in a dentine in a depth takes place also in the form of a triangle, but with an apex directed to the side of the pulp of a tooth.

On proximal surfaces (more frequently in the area of a contact point|station|) a decay spreads|widens| as two cones with a basis|foundation| on the enamel-dentine junction|compound|. But the character|nature| of direction of the enamel prisms determines more wider the entrance opening. The undermined edges|place| of the enamel are mostly observed|exist| in the direction of the masticatory surface and cutting edge|place|. The massive and cariesresistant lateral verges of the crown of the tooth prevent the dental caries from spreading to the sides of the crown.

Caries on the contact surfaces has a tendency to|by| spread in the cervical area of the crown. The precervical small carious cavities of the II-nd class sometimes are difficult to diagnose due to their hidden localization.

In the necks of the teeth a caries arises mainly on a vestibular surface and has a tendency to|by| the circular involvement of all the gingival areas.

Control questions to|by| practical lesson


              1. Is there any difference in the ways of spreading of cariosity in hard tissues of a tooth?

              2. Is there any difference in the ways of spreading of cariosity on various|diverse| surfaces of a tooth?

              3. Why are the teeth of the upper|top| jaw affected by a caries more often?

              4. What is the difference in the blood supply of the upper|top| and lower|bottom| jaws?

              5. Why does the caries in the first molar develop more frequently than in other teeth|?

              6. Name|call| topographical-anatomical classification of carious cavities after Black.

              7. Is there any conformity in the location of the carious cavities?

              8. What surface of the molars| are more frequently affected by caries?

              9. What surface of the premolars| are more frequently affected by caries?

              10. What surface of the canines| are more frequently affected by caries?

              11. What is the frequency of development of caries in non-vital teeth?

              12. What is the curvature of a crown of the tooth?

              13. What is the role of curvature of a crown in case of occurring of dental caries?

              14. What value|importance| does curvature of a crown of the tooth have in case of occurring of carious damage?

              15. What is thickness of the enamel in different|diverse| areas of the tooth?

              16. What is the role of thickness of the enamel in case of occurring of dental caries?

              17. How does a dental caries develop in the enamel of the masticatory surface?

              18. What is the chemical composition of the enamel and dentine?

              19. Does the chemical composition of the enamel and dentine influence on the activity of cariosity?

              20. How does a cariosity spread|widens| in the dentine?

              21. Why do the edges|place| of the enamel appear if they are deprived of the support of the dentine?

              22. How does the affection on the contact surfaces of a tooth spread|widens|?

              23. What prevents a dental caries from spreading into the sides if the contact surfaces are affected?

              24. What does exist tendency to|by| distribution of caries on contact surfaces?

              25. Why is it difficult to diagnose the small carious cavities of the class II?

              26. What are the peculiarities of spreading of caries on the precervical areas?



Situation tasks and test control
1. The teeth of what jaw are more frequently affected by caries?

A. Lower


B. Upper|top|

C. Identically

D. There is no right answer |absent|
2. Active movements|movement| of the lower|bottom| jaw provide|secure|:

A. Progress of cariosity

B. Slow blood supply|

C. Blood supply, good|kind| cleaning|clearing|, from food debris

D. The unsatisfactory cleaning|clearing| from food debris|food|

E. Pathological artrition teeth


3. What teeth are more frequently affected by caries?

A. Second incisors

B. First premolar|

C. First molar|

D. Dog-tooth|fang|

E. Second premolar|


4. How to distribute the groups of teeth after frequency of appearance of caries in an increasing order?

A. Frontal teeth of the lower|bottom| jaw, canine|fang|, premolar| and the upper|top| incisors, second molar|, the first molar|

B. Frontal teeth of the upper|top| jaw, canine|fang|, premolar| and the upper|top| incisors, the first molar|, the second molar|

C. Frontal teeth of the lower|bottom| jaw, the second molar|, the first molar|, dog-teeth|fang|, premolar| and the upper|top| incisors

D. Dog-teeth|fang|, premolar| and the upper|top| incisors, second molar|, the first molar|, frontal teeth of the lower|bottom| jaw

E. Dog-teeth|fang|, premolar| and the upper|top| incisors, frontal teeth of the lower|bottom| jaw, the second molar|, first molar|


5. What surfaces on the molars| are more frequently affected by dental caries?

A. Masticatory

B. Masticatory and proximal|

C. Aproximal

D. Precervical

E. Vestibular or buccal


6. What surfaces of the premolars| and incisors are more frequently affected by caries?

A. Masticatory and proximal|

B. Precervical

C. Vestibular or buccal

D. Masticatory

E. Aproximal


7. A caries in the enamel of fissures on masticatory surface penetrates deeper in the form of:

A. cone with a basis|foundation| on the enamel-dentine junction |compound|

B. triangle with a basis|foundation| in the deep layers of the pathological process

C. triangle with a basis|foundation| in the point of origin

D. triangle with a top in the point of origin

E. two cones on the enamel-dentine junction|compound|


8. A caries in a dentine penetrates deeper in the form of:

A. triangle with the apex|, directed to the side of a pulp of a tooth

B. triangle with a basis|foundation| in the point of origin

C. two cones on enamel-dentine junction|compound|

D. triangle with a basis|foundation| in the deep layers of the pathological process

E. cone with a basis|foundation| on enamel-dentine junction


9. due to what factor the activity of cariosity in the enamel and dentine is different|diverse|?

A. Histological structure|building|

B. Chemical composition|storage|

C. A+B


D. Belonging to|by| a certain|definite| group of teeth

E. It is not a matter of principle


10. Due to what changes the edges of the enamel, which are not supported by the dentine, are undermined:

A. to pathological changes|changing| in the enamel that takes place more rapidly

B. to pathological changes|changing| in the dentine that takes place slower

C. to pathological changes|changing| in the dentine that takes place more rapidly

D. there is no faithful answer
11. In the area of a contact point|station| of the proximal surfaces the affection spreads|widens| in the form of|appearance|:

A. triangle with the apex, directed to the side of the pulp of a tooth

B. one cone on the enamel-dentine junction|compound|

C. two cones are with a basis|foundation| on the enamel-dentine junction

D. triangle with the apex in the point of origin

E. in different|diverse| forms|shape|

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