The influence of the cervical cavity on the stress-strain state of the tooth

Relevance: a cavity in a tooth due to caries can change the stress-strain state in the tooth and lead to its splitting. According to the clinic, the probability of cracks and splits in the hard tissues of the tooth is affected not only by the size of the cavity, but also by its localization, which requires a comparative analysis of functional stresses in the tooth depending on the area affected by the carious process.

The purpose of the study: to analyze the effect of vertical and inclined loading on the stress-strain state of a single-root tooth with a cavity on the occlusal or neck surface and when replacing the defect with a composite material.

Materials and methods: three-dimensional mathematical modeling of the vital single-channel premolar of the mandible in the alveolar socket was carried out in accordance with the anatomical dimensions and physico-mechanical characteristics of tissues according to literary sources. The finite element method obtained data on the magnitude and nature of the distribution of functional stresses in the tooth when exposed to 150 N vertically and at an angle of 45 ° in models with a cavity on the occlusal surface or in the neck area, as well as during their restoration with composite material.

Results: the cervical localization of the cavity significantly increases the maximum stresses in the enamel, bringing them closer to the threshold values under vertical and inclined loads. In cavities of various localization, the most vulnerable point is the edge of the cavity. There are higher stresses in the cortical bone tissue in the presence of a cervical cavity in comparison with the occlusal cavity model. The replacement of a tooth tissue defect with a composite material helps to redistribute the load, reduce the maximum values in the enamel in all cases, and achieve sub-maximum values under vertical load when replacing the neck cavities with composite material.

Conclusions: localization of the cavity in the tooth affects the pattern and magnitude of stresses. In the cervical cavity, compared with the occlusal cavity, the stresses in the enamel are significantly increased, they exceed its strength limit under both vertical and inclined loads. The restoration of a defect with a composite material contributes to the redistribution of stresses and the displacement of their concentration points from the walls of the cavity to the occlusal surface and neck of the tooth. An inclined load is a risk factor for chipping the enamel walls with any localization of the cavity, and with an inclined load even after the defect has been replaced.

1. Therapeutic dentistry: a national guide / O.O. Yanushevich, L.A. Dmitrieva, Z.E. Revazova [et al.]. – 3rd edition, revised and expanded. Moscow: GEOTAR-Media Publishing Group Limited Liability Company, 2024. 1024 p. (National Guidelines). – ISBN 978-5-9704-8385-5. – DOI 10.33029/9704-8385-5-TD-2024-1-1024. – EDN CLWGFH.

2. Orthopedic dentistry: A national guide in 2 volumes / A.V. Akulovich, E.N. Anisimova, N.Y. Anisimova [et al.]. – 2nd ed., revised. and add.. – Moscow: Limited Liability Company Publishing Group GEOTAR-Media, 2022. – 416 p. – (National Guidelines ; 2). – ISBN 978-5-9704-6367-3. – DOI 10.33029/9704-6367-3-OD2-2022- 1-416. – EDN ULMYK.

3. The influence of biomechanical stress factors on the stress-strain state of the tooth and underlying bone tissue / E.A. Olesova, A.A. Ilyin, A.V.Em [et al.] // Russian Dental Journal. – 2024. – Vol. 28, No. 5. – pp. 462–468. – DOI 10.17816/dent634253. – EDN HVIETH.

4. Risk factors for cracks and fractures of teeth (according to a survey of dentists) / E.A. Olesova, A.A. Ilyin, S.D. Arutyunov [et al.] // Russian Dental Journal. – 2024. – vol. 28, No. 6. – pp. 562–568. – DOI 10.17816/dent634360. – EDN HFEBPX.

5. O’Brien W.J. Physical properties in dental materials and their selection //Illinois: Quintessence Publishing Co. – 1997.

6. Muslov S.A. Mechanical properties of tooth and dental tissues / S.A. Muslov, S.D. Arutyunov. Moscow: Practical medicine publishing house, 2020. 256 p. ISBN 978-5-98811-617-2. EDN ITZXLG.

7. Experimental modeling of the functional load of the lower jaw during implant-supported prosthetics in adverse clinical conditions / R.A. Rozov, V.N. Trezdubov, R.Sh. Gvetadze [et al.] // Dentistry. – 2022. – Vol. 101, No. 6. – pp. 28–34. – DOI 10.17116/stomat202210106128. – EDN KKPPHB.

8. Three-dimensional mathematical modeling of functional stresses around a dental implant in comparison with a single-root tooth / R.S. Zaslavsky, V.N. Olesova, Yu.A. Povstyanko [et al.] // Russian Bulletin of Dental Implantology. – 2022. – № 3–4(57–58). – Pp. 4–10. – EDN JHRTIG.

9. The stress-strain state of a non-removable prosthesis on implants under chewing load, depending on the angle of inclination of the walls of the abutment / S.I. Abakarov, D.V. Sorokin, V.Yu. Lapushko, S. S. Abakarova // Clinical dentistry. – 2023. – Vol. 26, No. 1. – pp. 147–157. – DOI 10.37988/1811-153X_2023_1_147. – EDN KBFJYD.