The etiology of abfraction defects is still in dispute. The etiology of these affections is not fully established. An important factor in the success of the treatment of abfraction defects of teeth by aesthetic restoration is the optimal choice of filling materials. It is impossible to improve the efficiency and quality of dental care without materials science. The aim of the study was to determine the strength of the restoration with uniaxial compression of the tooth before and after thermal cycling. The object of the study was 20 removed teeth with abfraction defects. The teeth were divided into two groups depending on the type of restoration. Half of the teeth were subjected to uniaxial loading in each group, the second half was subjected to thermal cycling before loading. Samples with indirect restorations showed greater strength both before and after thermal cycling.

1. http://www.iaeme.com/IJMET/index.asp 41 editor@iaeme.com
International Journal of Mechanical Engineering and Technology (IJMET)
Volume 10, Issue 05, May 2019, pp. 41–47, Article ID: IJMET_10_05_005
Available online at http://www.iaeme.com/ijmet/issues.asp?JType=IJMET&VType=10&IType=5
ISSN Print: 0976-6340 and ISSN Online: 0976-6359
© IAEME Publication
EXPERIMENTAL SUBSTANTIATION OF THE
CHOICE OF THE RESTORATION METHOD IN
THE CERVICAL AREA OF TEETH WITH
ABFRACTION DEFECTS
Enina Yu.I.
Department of Propedeutics of Dental Diseases, I.M. Sechenov First Moscow State Medical
University (Sechenov University), 119991, 8-2 Trubetskaya str. Moscow, Russian Federation
Sevbitov A.V.
Department of Propedeutics of Dental Diseases, I.M. Sechenov First Moscow State Medical
University (Sechenov University), 119991, 8-2 Trubetskaya str. Moscow, Russian Federation
Dorofeev A.E.
Department of Propedeutics of Dental Diseases, I.M. Sechenov First Moscow State Medical
University (Sechenov University), 119991, 8-2 Trubetskaya str. Moscow, Russian Federation
Pustokhina I.G.
Department of Propedeutics of Dental Diseases, I.M. Sechenov First Moscow State Medical
University (Sechenov University), 119991, 8-2 Trubetskaya str. Moscow, Russian Federation
ABSTRACT
The etiology of abfraction defects is still in dispute. The etiology of these affections
is not fully established. An important factor in the success of the treatment of
abfraction defects of teeth by aesthetic restoration is the optimal choice of filling
materials. It is impossible to improve the efficiency and quality of dental care without
materials science. The aim of the study was to determine the strength of the
restoration with uniaxial compression of the tooth before and after thermal cycling.
The object of the study was 20 removed teeth with abfraction defects. The teeth were
divided into two groups depending on the type of restoration. Half of the teeth were
subjected to uniaxial loading in each group, the second half was subjected to thermal
cycling before loading. Samples with indirect restorations showed greater strength
both before and after thermal cycling.
Key words: abfraction defect, cervical area of the tooth, tooth restoration, deformation,
thermal cycling
Cite this Article: Enina Yu.I., Sevbitov A.V., Dorofeev A.E., Pustokhina I.G., Experimental
Substantiation of the Choice of the Restoration Method in the Cervical Area of Teeth with
Abfraction Defects, International Journal of Mechanical Engineering and Technology 10(5),
2019, pp. 41–47.
http://www.iaeme.com/IJMET/issues.asp?JType=IJMET&VType=10&IType=5

2. Experimental Substantiation of the Choice of the Restoration Method in the Cervical Area of
Teeth with Abfraction Defects
http://www.iaeme.com/IJMET/index.asp 42 editor@iaeme.com
1. INTRODUCTION
A special place among the cervical non-carious affections of the hard tissues of the teeth is
cervical stress damage to the enamel or abfraction [5,11].
The etiology of abfraction defects is still in dispute. Despite numerous hypotheses put
forward by domestic and foreign scientists, the etiology of these affections has not been fully
established. Later, there were many studies demonstrating the connection of abfractions with
the violation of occlusive relationships. The concept of the concentration of occlusal stresses
as an abfraction trigger mechanism was investigated by G. McCoy (1982) [1]. Lee and Eakle
(1984) published a study on the possible role of stress on bending stress in the cervical area of
teeth in the etiology of abfractions. [12] In the future, Heymann H. O. and co-authors (1991)
[9], Grippo, J. O. (1991), Tepper H. W. (1996) [6] confirmed their data, proving that
abfraction defects is a result of biomechanical strain, associated with excessive occlusal forces
under static compression (swallowing, bruxism) and dynamic functions (chewing). [10,11]
The tension that occurs in the neck of the tooth, gradually provokes chronic fatigue in hard
tissues, followed by their destruction in this area. J. S. Rees (1988) indicates that the
development of abfraction defects is facilitated by the preparation of cavities, which weakens
the bumps of the tooth, as a result of which, under the influence of occlusive loading, their
deformation and displacement occurs. [4]
The modern theory, not excluding the influence of excessive occlusive loads on the tooth,
explains the etiology of abfractions as the process of destruction of enamel prisms as a result
of the piezoelectric effect. Under the action of atypical occlusive loads, a bending stress
occurs in the tooth, which causes an electrostatic process known as the piezoelectric effect. As
a result of this process, calcium ions are ejected from the crystal lattice of calcium
hydroxyapatite molecules of enamel prisms [5,9].
An important factor in the success of the treatment of pathology of hard tissues of teeth by
aesthetic restoration is the optimal choice of filling materials. [10]
Without materials science as a theoretical basis, it is impossible to improve the efficiency
and quality of dental care (Heintze S.D., Zimmerli В., 2011) [7] the practitioner is required to
understand the biomechanical basis of tooth functioning in connection with its anatomical
structures. [2,3].
In the study of available sources of literature revealed that the method of filling can not
qualitatively and permanently solve the problem of restoring the shape and function of teeth.
In this regard, to date, the desire of specialists to find new biologically inert materials and
methods for replacing defects in hard tissues of teeth remains relevant. [11]
In recent years, the interest in hybrid materials in dentistry has increased. [12]
Hybrid ceramics combines the positive properties of traditional ceramics and polymer for
CAD/CAM, which is associated with significant advantages in prosthetics. The elasticity of
this ceramic is close to that of natural dentine, as well as abrasive properties are identical to
natural enamel. This allows it to be used in places with high load in the cervical area. [8]
The aim of this study was to determine the strength of the restoration with uniaxial
compression of the teeth before and after thermal cycling.
2. MATERIALS AND METHODS
Determination of uniaxial compression strength is used to evaluate the strength characteristics
of a wide range of materials. The object of the study was 20 removed teeth with abfraction
defects. All teeth were processed by sandblasting Dento Prep, the particle size of aluminum
oxide 27 micron. The prototypes were divided into 2 groups depending on the method of

3. Enina Yu.I., Sevbitov A.V., Dorofeev A.E., Pustokhina I.G.
http://www.iaeme.com/IJMET/index.asp 43 editor@iaeme.com
restoration:1 group (10 teeth) – abfractive defects restored by hybrid ceramic inlays; 2 group
(10 teeth) – abfractive defects restored by direct restoration in adhesive technique with
composite filling material Estelyte Asteria.
For the test, samples were made: for teeth prepared using the methods described above,
the occlusal surface was cut with a disk for a flat surface, the tooth itself was mounted in a
steel sleeve with the help of Protacril-M self-hardening plastic. The samples were immersed
in a container of distilled water, which was placed in a thermostat with a temperature of
+37±1°C for 24 hours. Five samples were tested after 24 hours, and the remaining 5 were
subjected to thermal cycling.
After thermal Cycling, they were dried, the diameter measured with a micrometer to an
accuracy of 0.01 mm and installed in the test machine "Instron 5982", between two plane-
parallel carbide surfaces, for subsequent loading. A uniform compressive force with a traverse
velocity of 0.6 mm/min was applied to the sample until the sample was destroyed.
Compressive strength σ, MPa was calculated by the formula:
σ = 4F/πD2
where F – the load at fracture of the sample,
D – the diameter of the specimen, mm.
All calculations were carried out in the program «Bluehill 3».
3. RESULTS
The essence of the method is to apply a compressive load to the sample along the vertical
axis. The maximum strength of the sample is taken as the load it withstood before the
formation of cracks or loss of material from the cavity. Cracks, material loss are determined
according to the loading schedule, and are manifested in the form of an abrupt drop in the
applied load.
As a result of the experiment on the determination of the compressive strength of tooth
samples, the results are presented in the Table 1.
Table 1. Result of the experiment on the determination of the compressive strength of tooth samples
Sample
mark
The height
of the
sample
[mm]
Diameter
[mm]
Peak load
[N]
Move on
compressio
n [mm]
Tension
[MPa]
Deformatio
n [%]
Before
thermocycli
ng
Inlay 11,97±
0,22
7,17±0,02 5684,85±
120,98
1,03± 0,09 140,80±1,98 8,5±0,12
Filling 21,76± 0,11 6,72±0,04 2640,11±
100,09
0,74± 0,10 74,44±0,98 3,42±0,15
After
thermocycli
ng
Inlay 10,99± 0,13 7,26± 0,04 5405,76±
123,76
0,84±0,04 124,74±2,23 11,91±0,14
Filling 21,12± 0,23 6,12± 0,05 987,49±
14,54
0,34±0,06 59,32±0,97 4,75±0,12
With a load of 5684.85 ± 120.98N there was a rupture of the specimen with the tooth
tissues; the inset of the inlay did not occur in any of the specimens (Fig. 1, Fig. 2).

4. Experimental Substantiation of the Choice of the Restoration Method in the Cervical Area of
Teeth with Abfraction Defects
http://www.iaeme.com/IJMET/index.asp 44 editor@iaeme.com
Figure 1. Graph of tension and deformation of specimens without thermal cycling group 1
Figure 2. Sample tooth without thermocycling from 1 group.
When the load on the teeth with a direct restoration of 2640.11 ± 100.09N in all the tested
samples, material fell out of the cavity (Fig. 3, Fig. 4).
Figure 3. Graph of tension and deformation of specimens without thermal cycling group 2

5. Enina Yu.I., Sevbitov A.V., Dorofeev A.E., Pustokhina I.G.
http://www.iaeme.com/IJMET/index.asp 45 editor@iaeme.com
Figure 4. Sample tooth without thermocycling from 2 group.
After thermal cycling of teeth, the crack in the samples was recorded with a load of
5405.76 ± 123.76 N, the inlay did not fall out (Fig. 5, Fig. 6).
Figure 5. Graph of tension and deformation of specimens after thermal cycling group 1
Figure 6. Sample tooth after thermocycling from 1 group.

6. Experimental Substantiation of the Choice of the Restoration Method in the Cervical Area of
Teeth with Abfraction Defects
http://www.iaeme.com/IJMET/index.asp 46 editor@iaeme.com
In samples with direct restorations after thermal cycling, the separation of the filling from
the tooth tissues occurred at a load of 987.49 ± 14.54N (Fig. 7, Fig. 8).
Figure 7. Graph of tension and deformation of specimens after thermal cycling group 2
Figure 8. Sample tooth after thermocycling from 2 group.
4. DISCUSSION
The analysis of the literature data on abfractive defects of teeth testifies to the ambiguity and
inconsistency of the data on the etiology, pathogenesis, differential diagnosis of this type of
pathology, the consequence of which is the low efficiency of treatment of cervical lesions of
hard tissues of teeth in clinical conditions.
Kuroe T, Caputo AA, Ohata N, Itoh H. in the study of load distribution in defects in the
cervical region of the teeth and after its restoration shown that the presence of cervical lesions
changed the stress distribution caused by occlusive loading and concentrated stress inside the
cervical lesion. The shape and size of the lesion determined the degree of stress concentration.
And it was proved that the restoration of the cervical area of the tooth removed the
concentrated stress in the cavity of the defect. Our research has shown that the tabs of hybrid
ceramics provide better marginal adaptation than the restoration of a direct adhesive technique

7. Enina Yu.I., Sevbitov A.V., Dorofeev A.E., Pustokhina I.G.
http://www.iaeme.com/IJMET/index.asp 47 editor@iaeme.com
and relieve stress due to its mesh structure and is extremely resistant to transverse and
compressive loads, even after thermo cycling.
5. SUMMARY
In the experimental samples with indirect restoration, the difference in load before thermal
cycling and after was a slight, when with direct restoration the difference before thermal
cycling and after in the samples was in 1.5 times.
REFERENCES
[1] Makeeva I.M., Biakova S.F., Chuev V.P., Sheveliuk I.V. Electron microscopic study of
wedge-shaped defects of teeth on initial stage. Stomatologiia, 2009, 88(4), 39-42.
[2] Makeeva I.M., Sheveliuk I.V. [The role of abfraction in the aetiology of wedge-shaped
defects]. Stomatologiia, 2012. 91(1), 65-70.
[3] Grippo, J. O. Abfraction: a new classification of hard tissue lesions of teeth. Journal of
esthetic dentistry, 1991, 3, 14.
[4] Heintze S.D., Zimmerli B. Relevance of in-vitro tests of adhesive and composite dental
materials. A review in 3 parts. Part 2: non-standardized tests of composite materials.
Schweiz Monatsschr. Zahnmed. 2011,121(10), 916-930.
[5] Jakupović S, Anić I, Ajanović M, Korać S, Konjhodžić A, Džanković A, Vuković A.
Biomechanics of cervical tooth region and noncarious cervical lesions of different
morphology; three-dimensional finite element analysis. European Journal of Dentistry,
2016, 10(3), 413-418.
[6] Heymann H.O., Sturdevant J.R., Bayne S. Wilder A.D., Sluder T.B., Brunson W. D.
Examining toot flexure effects. The Journal of the American Dental Association, 1991,
122, 41-47.
[7] Kuroe T, Itoh H, Caputo AA, Konuma M. Biomechanics of cervical tooth structure
lesions and their restoration. Quintessence International, 2000, 31(4), 267-274.
[8] Kuroe T, Caputo AA, Ohata N, Itoh H. Biomechanical effects of cervical lesions and
restoration on periodontally compromised teeth. Quintessence Internationa, 2001, 32(2),
111-118.
[9] Lee W. C., Eakle W. S. Possible role of tensile stress in the etiology of cervical erosive
lesions of teeth. Journal of Prosthetic Dentistry, 1984, 52, 374-380.
[10] Mörmann, W., Stawarczyk, B., Ender, A., Sener, B., Attin, T., Mehl, A. Wear
characteristics of current aesthetic dental restorative CAD/CAM materials: Two-body
wear, gloss retention, roughness and Martens hardness. Journal of the Mechanical
Behavior of Biomedical Materials, 2013, 20(4), 113-125.
[11] Sevbitov A.V., Brago A.S., Enina Yu.I., Dorofeev A.E., Mironov S.N. Experience in the
application of hybrid ceramic restorations in the cervical region Asian Journal of
Pharmaceutics. 2018, 12(S3), 1106-1109.
[12] Rees J., Hammadeh M. Undermining of enamel as a mechanism of abfraction lesion
formation: a finite element study. European Journal of Oral Sciences, 2004, 112(4), 347-
352.