T.I. Ibragimov, professor, PhD med., honourable doctor of the RF,
V.A. Markin, professor, PhD med.,
A.V. Grinev, senior lecturer, PhD med.,
A.V. Viculin, senior laboratorian, PhD med.

«Cathedra» journal, № 40, 2012

Teeth restoration after endodontic treatment represents one of the most important stages of work of a dentist-orthopedist (1).

The rebuilding of tooth core may be defined as restoration of greatly destroyed tooth to reach the form, acceptable for its further preparation for artificial crown (5). The rebuilding of tooth core helps to form the tooth, also playing the role of intermediate restoration before preparing the tooth for artificial crown (4, 6).

To positive moments of tooth core rebuilding one may also attribute good edge seal of the restoration and bonding with hard tooth tissues, which taken together has a positive influence on the strength and service life of the restored tooth (7,8).

Widely spread recently have become methods of direct tooth core rebuilding with the use of special composite dental materials – «core-materials» (2). These materials are characterized by high strength, which has high importance since they serve as support of the whole restored tooth (3).

Jointly with Materials technology and Orthopedic dentistry cathedras of Moscow medical and dental university, JSC «StomaDent» has recently developed new national composite self-cure material for the rebuilding of tooth core: «DentaCor», which meets basic requirements for dental materials of this class.

Purpose of current research:

On clinical examples to demonstrate various variants of tooth core rebuilding with composite self-cure material «DentaCor».

Materials and methods:

«DentaCor» was used in 34 clinical cases (76 teeth cores rebuilt) in accordance with the following technique. The destroyed tooth or tooth core was prepared for the fixing of anchor pins (all pathologic tissues were removed, the root channel was drilled to not less than 1/2 of the root length). The pin was fixed by glass ionomer. The remaining tooth tissues were etched with 37% gel of ortho-phosphorus acid during 20 seconds. Then the gel was washed out by water, and tooth tissues were dried by air. Thereafter on the prepared tooth surface self-cure adhesive was placed and dried by air. «DentaCor» material was mixed on mixing pad at 1:1 proportion by disposable plastic spatulas to reach homogenous state in the course of 30 seconds. Then the tooth core was modeled. After it was modeled, it was prepared for the chosen construction. And finally all teeth cores were covered with temporary crowns.

In the first clinical case the tooth core was modeled with the use of a smoother. The material was placed with excess for the convenience of its further processing.

Picture 1. Teeth cores before placement of anchor pins	Picture 2. Anchor pins fixed by glass ionomer
Picture 3. Formed teeth cores	Picture 4. Teeth cores after preparation

In the second clinical case the tooth core was modeled with the use of a special cap-former which allows quick forming of the core and facilitates preparation of tooth for artificial crown, providing optimal cap.

Picture 5. Teeth cores before placing anchor pins	Picture 6. Anchor pins fixed by glass ionomer
Picture 7. Teeth cores formed with the use of special caps-formers
Picture 8. Teeth cores after preparation

In the third clinical case the tooth core was modeled with the use of a metal matrix and a matrix holder.

Picture 9. Teeth cores before placing anchor pins	Picture 10. Anchor pins fixed by glass ionomer
Picture 11. Tooth core formed with the use of a matrix
Picture 12. Tooth core after preparation

The results and their discussion

The evaluation of quality and effectiveness of teeth cores rebuilding with composite self-cure dental material «DentaCor» was carried out immediately after rebuilding and in the course of 1 month thereafter (while constant crowns were prepared). The integrity and edge adaptation of the rebuilt cores were analyzed. The results of this analysis are presented in tables 1 and 2:

Table 1.
Clinical evaluation of effectiveness of frontal teeth core rebuilding with composite self-cure dental material «DentaCor»

Immediately after the rebuilding of tooth core at frontal men’s group of teeth all 23 cores had integral structure, i.e. there were no pores, spallings, cracks.

Before the crowns were fixed on constant glass ionomer 23 teeth cores did not have visual changes and had integral structure.

Immediately after the rebuilding of tooth core at frontal women’s group of teeth 16 cores had integral structure, i.e. there were no pores, spallings, cracks. 1 core had a pore which appeared because of mistakes made during its forming. This drawback was eliminated.

Before the crowns were fixed on constant glass ionomer 17 teeth cores did not have visual changes and had integral structure.

The analysis of edge adaptation of the rebuilt cores at frontal group of teeth (by men and women) has shown that none of the cores had slot between tooth tissues and the composite material: immediately after the tooth core rebuilding and before the crowns fixation on constant glass ionomer (1 month later) as well.

Up to the present moment there was not a single case of cement break-up in the constant crowns after they have been fixed by constant cement.

Table 2.
Clinical evaluation of effectiveness of molar and premolar teeth cores rebuilding carried out by composite self-cure material «DentaCor»

Immediately after the rebuilding of tooth core at molar/premolar men’s group of teeth all 16 cores had integral structure, i.e. there were no pores, spallings, cracks.

Before the crowns were fixed on constant glass ionomer 16 teeth cores did not have visual changes and had integral structure.

Immediately after the rebuilding of tooth core at molar/premolar women’s group of teeth 20 cores had integral structure, i.e. there were no pores, spallings, cracks. 1 core had a pore which appeared because of mistakes made during its forming. This drawback was eliminated.

Before the crowns were fixed on constant glass ionomer 20 teeth cores did not have visual changes and had integral structure.

The analysis of edge adaptation of the rebuilt cores at molar/premolar group of teeth (by men and women) has shown that none of the cores had slot between tooth tissues and the composite material: immediately after the tooth core rebuilding and before the crowns fixation on constant glass ionomer (1 month later) as well.

Two women and 1 man (7 rebuilt teeth cores) wore temporary crowns in the course of 3 months (periodontal treatment was required). During this period and before the crowns were fixed on constant cement no visual changes of the cores took place, which preserved integral structure.

Up to the present moment there was not a single case of cement break-up in the constant crowns after they have been fixed by constant cement.

Conclusions.

Teeth cores rebuilt with composite self-cure dental material «DentaCor» have good adhesion with tooth tissues, are strong enough and easily worked with. While preparing the tooth core for crown one does not feel the transfer from dentine to the material, which no doubt will make the work of dentist-orthopedist easier. All this increases the speed of work and improves its quality.

In our opinion, most convenient is to rebuild tooth core with special caps-formers. Using them one may get almost finished tooth core, which has necessary form, conicity and this requires minimal preparation work.

Tooth core rebuilding with the use of «DentaCor» material will allow to improve significantly the quality of restoration and to diminish the number of possible complications in the distant future. And low cost of the material will allow a big number of dentists to use for teeth core rebuilding the material, specially designed for this purpose.

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