{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,28]],"date-time":"2026-07-28T14:23:43Z","timestamp":1785248623905,"version":"3.55.0"},"reference-count":49,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2025,2,20]],"date-time":"2025-02-20T00:00:00Z","timestamp":1740009600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"the School of Dental Medicine, University of Belgrade","award":["No. 451-03-66\/2024-03\/200129"],"award-info":[{"award-number":["No. 451-03-66\/2024-03\/200129"]}]},{"name":"the School of Dental Medicine, University of Belgrade","award":["No. 451-03-65\/2024-03\/200135"],"award-info":[{"award-number":["No. 451-03-65\/2024-03\/200135"]}]},{"name":"the School of Dental Medicine, University of Belgrade","award":["No 7475"],"award-info":[{"award-number":["No 7475"]}]},{"name":"the Faculty of Technology and Metallurgy","award":["No. 451-03-66\/2024-03\/200129"],"award-info":[{"award-number":["No. 451-03-66\/2024-03\/200129"]}]},{"name":"the Faculty of Technology and Metallurgy","award":["No. 451-03-65\/2024-03\/200135"],"award-info":[{"award-number":["No. 451-03-65\/2024-03\/200135"]}]},{"name":"the Faculty of Technology and Metallurgy","award":["No 7475"],"award-info":[{"award-number":["No 7475"]}]},{"name":"Science Fund of the Republic of Serbia","award":["No. 451-03-66\/2024-03\/200129"],"award-info":[{"award-number":["No. 451-03-66\/2024-03\/200129"]}]},{"name":"Science Fund of the Republic of Serbia","award":["No. 451-03-65\/2024-03\/200135"],"award-info":[{"award-number":["No. 451-03-65\/2024-03\/200135"]}]},{"name":"Science Fund of the Republic of Serbia","award":["No 7475"],"award-info":[{"award-number":["No 7475"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JFB"],"abstract":"<jats:p>Hydroxyapatite (HAP) inserts minimize restoration contraction by constituting a major part of the restoration; however, their effect on the relaxation of tooth tissues has not been previously tested. Finite element analysis was employed to estimate stress and displacement when HAP inserts with a thickness of 1.7 mm or 4.7 mm and a diameter of 4.7 mm were used to substitute for dentin. The volumetric contraction of the composite during polymerization, simulated through steady-state heat transfer analysis, yielded a contraction rate of 3.7%. Descriptive statistics revealed that the incorporation of HAP inserts reduced the displacement of dentin, enamel, and restoration caused by contraction by 44.4% to 66.7%, while maximal stress was reduced by 8.1% to 52%. Subsequent loading on the occlusal tooth surface showed that displacement values decreased by 12.1% to 33.3%, while maximum von Mises stress in enamel decreased by 32.8% to 40.6% with the use of HAP inserts. Although the maximum stress values in dentin were not significantly decreased (3% to 8.8%), the stress located at the bottom of the cavity was notably reduced, particularly in deep cavities at root canal entrances. The use of HAP inserts in restorative dentistry provides benefits for the preservation of prepared teeth, especially in preventing irreparable vertical root fractures of endodontically treated teeth.<\/jats:p>","DOI":"10.3390\/jfb16030075","type":"journal-article","created":{"date-parts":[[2025,2,21]],"date-time":"2025-02-21T07:53:06Z","timestamp":1740124386000},"page":"75","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Hydroxyapatite Dental Inserts for Tooth Restoration: Stress and Displacement Analysis"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4176-7083","authenticated-orcid":false,"given":"Maja Lezaja","family":"Zebic","sequence":"first","affiliation":[{"name":"School of Dental Medicine, University of Belgrade, Nebojsina 35, 11000 Belgrade, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1713-6540","authenticated-orcid":false,"given":"Aleksandar","family":"Bodic","sequence":"additional","affiliation":[{"name":"Faculty of Engineering, University of Kragujevac, Sestre Janji\u0107, 34000 Kragujevac, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6370-7167","authenticated-orcid":false,"given":"Djordje","family":"Veljovic","sequence":"additional","affiliation":[{"name":"Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11000 Belgrade, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7415-0453","authenticated-orcid":false,"given":"Tamara","family":"Matic","sequence":"additional","affiliation":[{"name":"Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11000 Belgrade, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1014-7589","authenticated-orcid":false,"given":"Jelena","family":"Carkic","sequence":"additional","affiliation":[{"name":"School of Dental Medicine, University of Belgrade, Nebojsina 35, 11000 Belgrade, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3071-4728","authenticated-orcid":false,"given":"Vladimir","family":"Milovanovic","sequence":"additional","affiliation":[{"name":"Faculty of Engineering, University of Kragujevac, Sestre Janji\u0107, 34000 Kragujevac, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,2,20]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"825","DOI":"10.1016\/S0142-1123(00)00052-9","article-title":"Fatigue of biomaterials: A review","volume":"22","author":"Teoh","year":"2000","journal-title":"Int. J. Fatigue"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"108852","DOI":"10.1016\/j.compositesb.2021.108852","article-title":"A review of dental composites: Challenges, chemistry aspects, filler influences, and future insights","volume":"216","author":"Aminoroaya","year":"2021","journal-title":"Compos. Part B Eng."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Alhussein, A., Alsahafi, R., Wang, X., Mitwalli, H., Filemban, H., Hack, G.D., Oates, T.W., Sun, J., Weir, M.D., and Xu, H.H. (2023). Novel Dental Low-Shrinkage-Stress Composite with Antibacterial Dimethylaminododecyl Methacrylate Monomer. J. Funct. Biomater., 14.","DOI":"10.3390\/jfb14070335"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"578","DOI":"10.1016\/j.dental.2021.01.013","article-title":"Photopolymerization shrinkage-stress reduction in polymer-based dental restoratives by surface modification of fillers","volume":"37","author":"Shah","year":"2021","journal-title":"Dent. Mater."},{"key":"ref_5","first-page":"248","article-title":"Beta quartz microcrystalline glass as megafillers for composites","volume":"68","author":"Bowen","year":"1989","journal-title":"J. Dent. Res."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"182","DOI":"10.4012\/dmj.12.182","article-title":"Polymerization shrinkage and contraction force of composite resin restorative inserted with \u201cMegafiller\u201d","volume":"12","author":"Tani","year":"1993","journal-title":"Dent. Mater. J."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1007\/s007840050105","article-title":"Inserts\u2014Megafillers in composite restorations: A literature review","volume":"4","author":"Federlin","year":"2000","journal-title":"Clin. Oral Investig."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"606","DOI":"10.1111\/j.1365-2842.2005.01459.x","article-title":"Ceramic inserts do not generally improve resin composite margins","volume":"32","author":"Strobel","year":"2005","journal-title":"J. Oral Rehabil."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"567","DOI":"10.1046\/j.1365-2842.1998.00281.x","article-title":"Marginal leakage in class II-restorations after use of ceramic-inserts luted with different materials","volume":"25","author":"Hahn","year":"1998","journal-title":"J. Oral Rehabil."},{"key":"ref_10","first-page":"1007","article-title":"Dental applications of calcium orthophosphates (CaPO4)","volume":"1","author":"Dorozhkin","year":"2019","journal-title":"J. Dent. Res."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"171","DOI":"10.1016\/j.dental.2014.11.017","article-title":"Bond strength of restorative materials to hydroxyapatite inserts and dimensional changes of insert-containing restorations during polymerization","volume":"31","author":"Lezaja","year":"2015","journal-title":"Dent. Mater."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"18200","DOI":"10.1016\/j.ceramint.2018.07.028","article-title":"Composite nanostructured hydroxyapatite\/yttrium stabilized zirconia dental inserts\u2014The processing and application as dentin substitutes","volume":"44","author":"Ayoub","year":"2018","journal-title":"Ceram. Int."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Matic, T., Zebic, M.L., Miletic, V., Trajkovic, I., Milosevic, M., Racic, A., and Veljovic, D. (2024). Hydroxyapatite-based dental inserts: Microstructure, mechanical properties, bonding efficiency and fracture resistance of molars with occlusal restorations. J. Biomed. Mater. Res.\u2014Part B Appl. Biomater., 112.","DOI":"10.1002\/jbm.b.35331"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"415","DOI":"10.4103\/JIOH.JIOH_11_21","article-title":"Applications of finite element analysis in dentistry: A review","volume":"13","author":"Shivakumar","year":"2021","journal-title":"J. Int. Oral Health"},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Bandela, V., and Kanaparthi, S. (2020). Finite element analysis and its applications in dentistry. Finite Element Methods and Their Applications, IntechOpen Limited.","DOI":"10.5772\/intechopen.94064"},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Alemayehu, D.B., and Jeng, Y.R. (2021). Three-Dimensional Finite Element Investigation into Effects of Implant Thread Design and Loading Rate on Stress Distribution in Dental Implants and Anisotropic Bone. Materials, 14.","DOI":"10.20944\/preprints202109.0221.v1"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"367","DOI":"10.1016\/j.msec.2019.01.104","article-title":"The effect of different occlusal contact situations on peri-implant bone stress\u2014A contact finite element analysis of indirect axial loading","volume":"99","author":"Brune","year":"2019","journal-title":"Mater. Sci. Eng. C Mater. Biol. Appl."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Pirmoradian, M., Naeeni, H.A., Firouzbakht, M., Toghraie, D., Khabaz, M.K., and Darabi, R. (2020). Finite element analysis and experimental evaluation on stress distribution and sensitivity of dental implants to assess optimum length and thread pitch. Comput. Methods Programs Biomed., 187.","DOI":"10.1016\/j.cmpb.2019.105258"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"870","DOI":"10.1016\/j.jcms.2015.03.025","article-title":"Impact of the lower third molar presence and position on the fragility of mandibular angle and condyle: A Three-dimensional finite element study","volume":"43","author":"Antic","year":"2015","journal-title":"J. Cranio-Maxillo-Facial Surg. Off. Publ. Eur. Assoc. Cranio-Maxillo-Facial Surg."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"e214","DOI":"10.1016\/j.oooo.2019.06.009","article-title":"Mandibular 3-dimensional finite element analysis for a patient with an aggressive form of craniofacial fibrous dysplasia","volume":"128","author":"Kihara","year":"2019","journal-title":"Oral Surg. Oral Med. Oral Pathol. Oral Radiol."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"110","DOI":"10.4103\/2231-0762.178743","article-title":"Revolution in Orthodontics: Finite element analysis","volume":"6","author":"Singh","year":"2016","journal-title":"J. Int. Soc. Prev. Community Dent."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1055\/s-0042-1747955","article-title":"Influence of Different Restoring Materials on Stress Distribution in Prosthesis on Implants: A Review of Finite Element Studies","volume":"17","author":"Vieira","year":"2023","journal-title":"Eur. J. Dent."},{"key":"ref_23","first-page":"e1411","article-title":"Efficacy of the finite element analysis in assessing the effects of light curing on the mechanical properties of direct restorative composites: A systematic review","volume":"16","author":"Yadalam","year":"2024","journal-title":"J. Clin. Exp. Dent."},{"key":"ref_24","first-page":"31","article-title":"Marginal adaptation of Class II composite fillings: Guided polymerization vs reduced light intensity","volume":"1","year":"1999","journal-title":"J. Adhes. Dent."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"306","DOI":"10.1177\/10454411970080030501","article-title":"Current concepts on adhesion to dentin","volume":"8","author":"Eick","year":"1997","journal-title":"Crit. Rev. Oral Biol. Med."},{"key":"ref_26","unstructured":"McCabe, J.F., and Walls, A.W. (2013). Applied Dental Materials, John Wiley & Sons."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1463","DOI":"10.1016\/j.msec.2008.12.001","article-title":"Thermal expansion of hydroxyapatite between \u2212100 \u00b0C and 50 \u00b0C","volume":"29","author":"Miyazaki","year":"2009","journal-title":"Mater. Sci. Eng. C"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"612","DOI":"10.1016\/j.dental.2021.01.009","article-title":"Openmandible: An open-source framework for highly realistic numerical modelling of lower mandible physiology","volume":"37","author":"Vukicevic","year":"2021","journal-title":"Dent. Mater."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"556","DOI":"10.1016\/j.jdent.2015.02.011","article-title":"Influence of dental restorations and mastication loadings on dentine fatigue behaviour: Image-based modelling approach","volume":"43","author":"Vukicevic","year":"2015","journal-title":"J. Dent."},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"He, J., Zheng, Z., Wu, M., Zheng, C., Zeng, Y., and Yan, W. (2021). Influence of restorative material and cement on the stress distribution of endocrowns: 3D finite element analysis. BMC Oral Health, 21.","DOI":"10.1186\/s12903-021-01865-w"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"2171","DOI":"10.1016\/j.ceramint.2008.11.028","article-title":"Influence of microstructure and phase composition on the nanoindentation characterization of bioceramic materials based on hydroxyapatite","volume":"35","author":"Tang","year":"2009","journal-title":"Ceram. Int."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"389.e1","DOI":"10.1016\/j.prosdent.2019.06.023","article-title":"Architecture and design of a robotic mastication simulator for interactive load testing of dental implants and the mandible","volume":"122","author":"Tahir","year":"2019","journal-title":"J. Prosthet. Dent."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"938","DOI":"10.1016\/j.dental.2023.08.177","article-title":"Load capacity and fracture modes of instrumented tooth roots under axial compression","volume":"39","author":"Lin","year":"2023","journal-title":"Dent. Mater."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"731","DOI":"10.1016\/j.dental.2021.01.020","article-title":"Occlusal stress distribution and remaining crack propagation of a cracked tooth treated with different materials and designs: 3D finite element analysis","volume":"37","author":"Kim","year":"2021","journal-title":"Dent. Mater."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"871","DOI":"10.1016\/j.joen.2016.12.028","article-title":"Higher maximal occlusal bite force in endodontically treated teeth versus vital contralateral counterparts","volume":"43","author":"Awawdeh","year":"2017","journal-title":"J. Endod."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"661","DOI":"10.4012\/dmj.28.661","article-title":"Effects of different ceramic and composite materials on stress distribution in inlay and onlay cavities: 3-D finite element analysis","volume":"28","author":"Yamanel","year":"2009","journal-title":"Dent. Mater. J."},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Neto, M.A., Roseiro, L., Messias, A., Falacho, R.I., Palma, P.J., and Amaro, A.M. (2021). Influence of cavity geometry on the fracture strength of dental restorations: Finite element study. Appl. Sci., 11.","DOI":"10.3390\/app11094218"},{"key":"ref_38","doi-asserted-by":"crossref","unstructured":"Ouldyerou, A., and Mehboob, H. (2023). Biomechanical performance of resin composite on dental tissue restoration: A finite element analysis. PLoS ONE, 18.","DOI":"10.1371\/journal.pone.0295582"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"603","DOI":"10.1016\/S0109-5641(03)00002-2","article-title":"Influence of microstructure and chemistry on the fracture toughness of dental ceramics","volume":"19","author":"Quinn","year":"2003","journal-title":"Dent. Mater."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"595","DOI":"10.1016\/j.ceramint.2009.09.038","article-title":"Microwave sintering of fine grained HAP and HAP\/TCP bioceramics","volume":"36","author":"Zalite","year":"2010","journal-title":"Ceram. Int."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"850","DOI":"10.1111\/iej.12381","article-title":"Mechanical weakening of devitalized teeth: Three-dimensional Finite Element Analysis and prediction of tooth fracture","volume":"48","author":"Zelic","year":"2015","journal-title":"Int. Endod. J."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1111\/etp.12089","article-title":"Biomechanics of fractures in endodontically treated teeth","volume":"33","author":"Kishen","year":"2015","journal-title":"Endod. Top."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"1405","DOI":"10.1016\/j.joen.2007.08.015","article-title":"A six year evaluation of cracked teeth diagnosed with reversible pulpitis: Treatment and prognosis","volume":"33","author":"Krell","year":"2007","journal-title":"J. Endod."},{"key":"ref_44","doi-asserted-by":"crossref","unstructured":"Ninkovic, N., Opacic Galic, V., Milosevic, M., Trajkovic, I., Kuzmanovic Pficer, J., Bajuk-Bogdanovi\u0107, D., Milovanovic, P., Yashin El-Bacha, D., Djuric, M., and Miletic, V. (2024). Effects of minimally invasive endodontic access cavity in molar teeth on polymerization, porosity and fracture resistance. Sci. Rep., 14.","DOI":"10.1038\/s41598-024-72643-1"},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"426134","DOI":"10.1155\/2013\/426134","article-title":"How can stress be controlled in endodontically treated teeth? A 3D finite element analysis","volume":"2013","author":"Bala","year":"2013","journal-title":"Sci. World J."},{"key":"ref_46","doi-asserted-by":"crossref","unstructured":"Zhou, Y., Hu, Z., Hu, Y., Gao, A., Pan, X., Tang, R., and Lin, Z. (2023). Patterns of stress distribution of endodontically treated molar under different types of loading using finite element models\u2014The exploring of mechanism of vertical root fracture. J. Mech. Behav. Biomed. Mater., 144.","DOI":"10.1016\/j.jmbbm.2023.105947"},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"690","DOI":"10.1016\/j.dental.2017.03.014","article-title":"Mechanical behavior of bulk direct composite versus block composite and lithium disilicate indirect Class II restorations by CAD-FEM modeling","volume":"33","author":"Ausiello","year":"2017","journal-title":"Dent. Mater."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"890","DOI":"10.1016\/j.prosdent.2020.03.009","article-title":"Biomechanical behavior of endocrown restorations with different CAD-CAM materials: A 3D finite element and in vitro analysis","volume":"125","author":"Zheng","year":"2021","journal-title":"J. Prosthet. Dent."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"1155","DOI":"10.1016\/S0021-9290(02)00085-4","article-title":"Statistical methods in finite element analysis","volume":"35","author":"Dar","year":"2002","journal-title":"J. Biomech."}],"container-title":["Journal of Functional Biomaterials"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2079-4983\/16\/3\/75\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T16:39:01Z","timestamp":1760027941000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2079-4983\/16\/3\/75"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,2,20]]},"references-count":49,"journal-issue":{"issue":"3","published-online":{"date-parts":[[2025,3]]}},"alternative-id":["jfb16030075"],"URL":"https:\/\/doi.org\/10.3390\/jfb16030075","relation":{},"ISSN":["2079-4983"],"issn-type":[{"value":"2079-4983","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,2,20]]}}}