Control questions to|by| practical lesson
What are the rules for preparation of access cavities in endodontics?
Differences in the work with K-file and H-file in root canal treatment.
What are the stages of root treatment in endodontics?
Describe methods of root instrumentation.
Describe Step-back technique in root canal instrumentation.
Describe Crown-down technique in root canal instrumentation.
What groups of medications are used for root canal cleaning?
What are the demands to antiseptics for root canal cleaning?
How does antiseptic Na hypochloride influence vital tissues?
Peculiarities of the treatment of the apical part of root canal?
Situation tasks and test control
1. Sonic and ultrasonic root canals preparation systems are used for:
a. the coronal part of the crown
b. its rotary endodontic tools
c. activating the irrigation solutions
d. good method for the root canal preparation
2. For the root canal localization it is preferable to use:
A. periodontal probe
C. round-shaped drill
3. What definition as to the barber broach is correct?
a. barber broach can be used in curved canals
b. barber broach is carried out (put into operation) in the full length
c. barber broach can be carried out with press into the root canal
d. the size of barber broach makes it possible to extract the pulp, avoiding the root canal walls
4. Barber broach is a flexible manual endodontic tool with sharp hooks and is used for:
A. extraction of the roof of the pulp chamber
B. extraction of the pulp tissue from the root canal
C. finishing the root canal dentin
D. making the apical barrier in the root canal apex
5. What is the difference between K-file and K-reamer?
A. Do instruments make the square cuts prior to preparation, twist method
B. In the same length the spiral amount is different
C. All the reamers make the triangular cuts prior to preparation
D. K-file can be used as mechanical and manual endodontic tools
6. A working part of the endodontic spreader is:
a. smooth with a dull tip with a little conical form
b. smooth with a dull tip with a cylindrical form
c. smooth with a sharp tip with a slight conical form
d. smooth with a sharp tip with a cylindrical form
7. The important factor in case of the endodontic tool fracture in the root canal is:
8. in the majority cases the H-file is used for:
a. widening the root canal from apex to the root canal entrance
b. making the round shaped form in the apical 1/3 length
c. preparing the canal for restoration with a pin
d. for the dentin cutting with a rotary movement
9. Mechanical 3-th size piesoreamer is used for:
A. extraction of the rest of the pulp and tissues
B. instrumental preparation of the apical and medium parts of the root canal
C. finishing and polishing of all the canal walls
D. finishing and widening the crown 1/3 length of the root canal
10. What rotary tools are used for widening the coronal part of the root?
A. Round-shaped bur
B. Gates-Glidden bur
C. Inverted-cone bur
D. Fissure-straight bur
Clincal endodontics: a textbook /Leif Tronstad.– 3rd rev. ed.– New Yourk, 2009.– 249 p.
Stephen Cohen, Richard C. Burns. Pathways of the pulp. Eighth edition.– Mosby, 2002.– 1031 p.
Fan B, Wu M-K, Wesselink PR. Leakage along warm gutta-percha fillings in the apical canals of curved roots. Endod Dent Traumatol 2000;16:29-33.
Glosson CR, Haller RH, Brent Dove S, del Rio CE. Comparison of root canal preparations using NiTihand, NiTi engine-driven and K-flex endodontic instruments. J Endod 1995;21:146-51.
Molven O, Halse A, Grung B. Surgical management of endodontic failures: indications and treatment results. Int Dent J 1991;41:33-42.
Seltzer and Bender’s. Dental pulp // Quintessence Publishing, 2002.
Practical lesson No 37
Theme: Root canal filling materials. Classification. Main demands. Partially hardening sillers. Composition. Characteristic. Indications for use.
Short description of a theme
For the root canal obturation three main types of the points are used: Gutta-percha, resilon and silver.
Points can be divided into:
metal: silver, titanium
nonmetal: gutta-percha, plastic, resilon
Gutta-percha is a polymer matter, which composites from the polyizopren, which obtained from the Malaysia tropical tree. Gutta-percha – the coagulated, dried, purified latex of trees of the genera Palaquium and Payena, most commonly Palaquium gutta; used in orthopedics for fracture splints, in surgery for temporary sealing of cavities and in dentistry, in the form of cones for filling the root canal and in the form of sticks for sealing cavities over treatment.
As a polymer, this matter has a viscous elasticity feature. It means, that in a solid substance this matter possesses elasticity propeties, but in liquid is a low flow fluid. On heating, gutta-percha becomes soft quite easy. This material heated to 65ºC temperature turns into liquid. It can be solved by chloroform, eucalyptol xyleni.
The gutta-percha points can be standard and accessory.
The guttapercha points consist of 60-70% ZnO, 17% hard metals salts, 1-4% different kinds of wax, antioxidants and polymer compositions. The gutta-percha points contain just 20% of genuine guttapercha. It can have α and β forms. On the heating to 42ºC - 44ºC β form is converted into the α form. Absolute guttapercha dissolution occures in 56º C - 64ºC. After cooling gutta-percha has a high shrinkage level. The standard points have the same size that the standard endodontic tools. The dentist can choose the tape of the point. It may be 02, 04, 06 type.
The main best feature of the gutta-percha points is their biocompatibility. So this matter does not irritate the periapical tissue. This point is x-ray visible, does not cause the discolouration of the tooth and can be removed from the canal easily.
Disadvantages: The single gutta-percha point fails to provide the hermetic root canal isolation and protect it against the spread of microbes.That is why it is recommended to use points with a sealer to provide better root canal hermetization. It has no adhesion to the dentin. The thin points are flexible that makes it difficult to insert them into the canal.
The ISO standard points:
accessory 15-55 (extra-fine,fine-fine,medium-fine,fine, fine-medium, medium, medium-large, large, extra-large
Length 28 mm
Silver points are used as fillers from 30s of the XX century. The metal posts can not provide the 3D root canal obturation. The microleakage level is high. The silver points ISO sizes are: 010, 015 and 020. The silver points can corrode in blood and lymph. It forms the oxides of argentum, having a toxic effect on the cells and tissues. These points can change the colour of the tooth.
Methods of the root canal obturation.
a) Cold gutta-percha points:
central point method
lateral compaction method
b) Chemical-plastificated cold gutta-percha method with usage of the special oil solutions:
c) Warm gutta-percha obturation method
1. Vertical condensation
2. Fragmentated gutta-percha obturation
3. lateral-vertical condensation
4. Termomechanical condensation
d) Termoplastificated gutapercha obturation
1. Injection method
2. two-phases gutapercha
3. hard-rod fitting method
The lateral compaction method means the 3D root canal obturation without the thermal or chemical guttapercha softening. This method can help to prevent the gutta-percha shrinkage which can appear after the heating, and problems with the point fitting. This method means that we have to choose the suitable master-point which has the same size as the last endodontic tool which was used for the apical part of the root canal preparation. After that the doctor has to fit this point on the whole length to the root canal and check the position with the help of the periapical x-ray. Correct the point if it is necessary. Mark the point relatively the reference on the occlusal or incisal surface and remove it from the root canal. The point has to be covered by sealer and fitted in the root canal to the whole length to the mark The sealer can be put inside the canal with the help of lentulo or manually. The spreader should be inserted into in the root canal to the apical narrowing if it is possible. The spreader’s size must be smaller on the first step of obturation and it has to penetrate inside the canal as deep as it is possible, but not deeper than the apical narrowing. Later the greater sizes of spreader are used. The srpeader compact the guttapercha to the lateral walls and make a space for the additional points. Spreader has to be removed from the root canal after 20 sec. The additional point which is covered by the sealer is placed on the same length while the lateral compaction. The additional point shouldn’t be softened. This procedure should last to the full root canal obturation. Cut the ends of the points in the crown. The x-ray control should be made.
The one point method means that the root canal is obturated by one point and sealer. With the help of endodontic tools the apical narrowing is formed. The size and the shape of the post have to be the same that the last tool for root canal formation. For this purpose it is recommended to use Ni-Ti rotary tools. After that we have to fit this point on the whole length to the root canal and check the position with help of the periapical x-ray. Correct the point if it is necessary. Mark the point relatively the reference on the occlusal or incisal surface and remove from the root canal.Cover the walls by the sealer. The point should be covered by sealer and fitted in the root canal to the whole length to the mark. Cut the ends of the points which are situated in the crown.
Control questions to|by| practical lesson
What are the fillers that can be used for the root canal obturation?
What is the composition of the gutapercha point?
What is the composition of the resilon point?
What is the benefit in guttapercha points use?
What is the benefit in resilon points use?
Gutta-percha points: features, indication for use.
Resilon points: features, indication for use.
Silver points: features, indication for use.
Describe the lateral compaction method of the root canal obturation.
Describe the vertical condensation method of the root canal obturation.
Describe the one point method of the root canal obturation.
Describe the method of the root canal obturation with help of the ultrasonic plastification.
Describe the method of the root canal obturation with help of the gutta-condensor.
Describe the method of the root canal obturation with help of the Ultrafil system.
What is meant under the definition „fillers”?
What indications and contraindications for the fillers use do you know?
What indications and contraindications for the gutta-percha points use do you know?
What indications and contraindications for the silver points use do you know?
What indications and contraindications for the resilon points use do you know?
Compare the gutta-percha and silver points.
Compare the gutta-percha and resilon points.
Compare the resilon and silver points.
Compare the vertical condensation method and the lateral compaction method of the root canal obturation
Compare the vertical condensation method and the method of the root canal obturation with help of the gutta-condensor
Metal points: general classification. What are the characteristic features of points. Features. Indication for use.
Resilon points: general classification. What are the characteristic features of the resilon points. Features. Indication for use.
Gutta-percha points: general classification. Characterize the gutta-percha points. Features. Indication for use.
|fabric|Situation tasks and test control
1. For how long does the hot gutta percha possess its ability to condensation?
A. 5 sec
B. 30 sec
C. 1 min
D. 2 min
2. The second upper incisor root canal is prepared to the working length with No 35 К-file. What gutta percha points can be used for the root canal filling?
A. gutta percha point No 30
B. gutta percha point No 35
C. gutta percha point No 40
D. All is right
3. Which of the assertions as to the silver points is true?
A. Silver content in them is equal to 70%
B. Texture of their surface does not influence on the sealer adhesion
C. They prove to be the least toxic in endodontics
D. They can be exposed to corrosion that has cytotoxic affect
4. Standard gutta percha post are used as the basic posts, because they are:
A. long, cone-shaped and thermoplastic
B. they can easily penetrate into the narrow, curved, canals
C. of the same diameter and cone-shaped with instruments used for root canals
D. tough, strong and are easily inserted into the canal
5. If the roentgenography (X-ray) reveals that the standard point is too short, than the dentist can:
A. use the lubricant for its deeper insertion
B. widen the canal by H-file (its dimensions corresponds to master file) and repeat the insertion of the point
C. use the new point but with smaller dimension
D. apply it with apical effort
6. In case the X-ray shows that the standard gutta percha point is a little bit shorter (up to 0,5 mm), than the dentist can:
A. select the most suitable point among the rest of the same size
B. widen the canal with a help of K-file with a proper size
C. use the lubricant for inserting the post with the apical effort
D. use it, taking into account the necessity in filling a gap with a sealer
7. In case the post is too long, the dentist can:
A. select the point of greater size
B. make shorter for 1 mm
C. make shorter with, using the Maillefer caliber-rule
D. insert point against the stop and shorten its excess according to the X-ray showings
8. If it occurs that during the filling with a point, the master post corresponds to the working length, but there is a space in the canal the dentist is:
A. to fill it with the excessive amount of sealer
B. to insert along with sealer the additional 1-2 posts
C. while cutting the posts by hot plugger it is recommended to condensate gutta-percha by cold plugger
D. all above mentioned cases
9. In what cases the obturation by a single gutta percha sealer point with sealer is indicated?
A. narrow (20-25) and curved canal after preparation
B. slightly curved canal of the lateral upper incisor
C. an undeveloped canal in children
D. in all above-mentioned cases
10. In what cases the obturation of a canal by lateral condensation method is recommended?
A. narrow (20-25) and curved canal after preparation
B. slightly curved canal of the upper lateral incisor
C. an undeveloped canal of the upper lateral incisor
D. in all above-mentioned cases
E. in all above-mentioned cases except for ….. A
11. Which of the below-mentioned instruments and materials proved to be unnecessary for the lateral condensation?
B. Standard gutta percha post
12. Which of the belowmentioned demands as to the form of the canal preparation proved to be unnecessary for the tooth filling by lateral condensation?
A. Apical narrowing
B. Apical projection
C. Even cone-shaping
D. Smooth walls
E. round or oval form on transversal incision
13. How is the sealer introduced in lateral condensation?
A. By a canal filler with 200 rotations per minute that completely fills the canal
B. A small amount of sealer is introduced into the canal with a help of canal filler (200 rotations per minute)
C. A small amount of sealer is introduced into the canal with a help of manual canal filler
D. Method of introduction and amount of sealer are not important
14. The characteristics of obturation of the canal system in case of proper lateral condensation. Which of the below enumerated judgements are incorrect?
A. There is no material in the lateral canals
B. Gutta-percha is in the lateral canals
C. Sealer is in the lateral canals
D. Magistral canal is filled geometrically
15. Which of the enumerated statements proved to be correct?
A. Lateral condensation – the best filling
B. Vertical condensation – the best filling
C. Both fill the lateral canals with certainty
D. The ability to fill the canals depends on the form of the canal which is to be prepared
16. Which of the enumerated instruments and materials proved to be unnecessary for the vertical condensation?
B. Gutta-percha based
C. Spreader – heat carrier
E. Over for the gutta percha heater
17. In classical technique of the vertical condensation the warning-up of gutta percha makes it soft. Which of the following statements proved to be correct?
A. Before warming, the gutta percha-based post is adjusted but not tightly along the length and diameter of the canal
B. Standard post is warmed up outside the canal
C. Gutta percha-based post becomes soft in the canal due to the use of a heated acute-edged smooth instrument with regard for the length and diameter of the canal
D. The heated plugger makes the gutta percha – based post soft
18. Which of the enumerated statements, as to the form of the canal that is to be prepared, is obligatory for the cervical condensation of the canal?
A. The presence of retention in the apical part of the canal
B. Even cone-shaping
C. Smooth walls
D. Round or oval form on the transversal incision
19. Working part of instruments for root canal filling. Which of the following instruments is defined as a revolving condensor?
20. Which of the enumerated instruments and materials proved to be unnecessary for filling with thermafil?
B. Carrier of gutta percha – thermofil
C. Spreader – heat carrier
D. Over for gutta percha heating
21. What method of gutta percha filling the thermafil-based obturation is referred to?
A. The application of cold gutta percha
B. The application of gutta percha softened by chloroform
C. The application of gutta percha softened by intracanal heat
D. The application of gutta percha softened by extracanal heat
22. What method of obturation the thermofil-filling is referred to?
A. Method of lateral condensation
B. Method of central condensation
C. Method of vertical condensation
23. The best facilities for gutta percha sterilization are the use of:
A. 90% alcohol
B. 3% hydrogen peroxide
C. 70% alcohol
D. 5,25% sodium hypochloride
24. For gutta percha sterilization it is preferable to use:
A. 90% alcohol
B. 3% H2O2
C. 70% alcohol
D. 5,25% NaOCl
25. The main purpose of canal obturation is:
A. to keep the balance of both the post material and root cement in the canal
B. three-dimensional filling of the canal space
C. the isolation of the basic canal from the tissue liquids
26. What is the obturation purpose?
A. Balancation of filler and sealer amount in the root canal
B. Root canal 3D obturation
C. Basic root canal isolation from surrounded tissue liquid
D. Filling the lateral and periapical endodontic lesions
27. The best filling material must:
A. possess a sufficient shrinkage for canal filling
B. readily fill the canal laterally and apically, adjoining its walls
C. resolve under the influence of the tissue fluids, without causing irritation
D. possess spongy surface for supporting the tissue growth
28. The best canal cement used with a semisolid point:
A. fills the roughness between the filling and canal walls
B. as a rule, irritates the periapical tissues
C. is radiopaque on applying, but not in final hardening
D. influences insignificantly on the final result of treatment
29. Standard gutta percha posts are used as the main post because they:
A. are long, cone-shaped and soluted in the chloroform
B. penetrate easily into the narrow curved canals
C. their diameter and form is similar to the diameter and form of the instruments used for root canals
30. Standardizated gutta percha points are used as master points because:
A. they are long, taped and can be solved in chloroform
B. can be good adaptated in curved root canals
C. have the same diameter and shape as root canals endodontic tools
D. they are hard,straight and can be easily adapted in the root canal