1Instructor at the Conservative Dentistry Department, Faculty of Dentistry, Alexandria University, Alexandria, Egypt
2-Professor of Fixed Prosthodontics, Conservative Dentistry Department, Faculty of Dentistry, Alexandria University, Alexandria, Egypt.
3Professor of Dental Biomaterials, Dental Biomaterials Department, Faculty of Dentistry, Alexandria University, Alexandria, Egypt.
Abstract
INTRODUCTION: Chipping of the porcelain veneer was a common failure of zirconia based restorations, especially in the presence of high occlusal loads. The development of full-contour monolithic zirconia (MZ) restorations promises an end to the heartbreak of fractured esthetic porcelain on posterior restorations. The clinical recommended thickness of zirconia monolithic restorations has not been reported. It is essential to find out a proper thickness guarantee not only the load bearing capacity but also conservation of dental hard tissues. OBJECTIVES: was to evaluate the failure load of two different preparation designs – (classical and conservative) – in three units monolithic zirconia fixed partial dentures. MATERIALS AND METHODS: 2 parallel groups (n = 5/group) examined in this study. Group I: Classical tooth preparation design with occlusal reduction of 1.5 mm and rounded 1 mm finish line. Group II: Conservative tooth preparation design with occlusal reduction 0.5 mm and rounded 0.2 mm finish line. All fixed partial dentures (FPDs) adhesively luted on epoxy resin dies and subjected to thermal cycling and cyclic loading corresponding to 6 months of clinical service. Specimens then loaded till failure in a universal testing machine. The load of failure recorded in Newton. Fractographic analysis was done using stereomicroscope, scanning electron microscope (SEM) and confocal laser scanning microscope (CLSM). Data statistically analyzed using Student t-test. RESULTS: None of the FPDs failed during the aging process. Mean of failure load of Group I was 1317.36 ± 186.11 N and for Group II was 1215.92 ± 217.03 N without significant difference between the groups (P =0.450). CONCLUSIONS: The conservative tooth preparation design of the posterior three units FPDs was a very good alternative to the classical one. Aging behavior, translucency testing, color reproduction and long-term clinical performance need to be further assessed before recommending this conservative FPDs design for daily practice.
Madfa AA, Al-Sanabani FA, Al-Qudami NH, et al. Use of zirconia in dentistry: An overview. The Open Biomaterials Journal. 2014;5(1).
Tsalouchou E, Cattell MJ, Knowles JC, et al. Fatigue and fracture properties of yttria partially stabilized zirconia crown systems. Dental materials. 2008;24(3):308-18.
Mosharraf R, Rismanchian M, Savabi O, et al. Influence of surface modification techniques on shear bond strength between different zirconia cores and veneering ceramics. The journal of advanced prosthodontics. 2011;3:221-8.
Vichi A, Louca C, Corciolani G, et al. Color related to ceramic and zirconia restorations: a review. Dental materials. 2011;27:97-108.
Comlekoglu M, Dundar M, Özcan M, et al. Influence of cervical finish line type on the marginal adaptation of zirconia ceramic crowns. Operative dentistry. 2009;34:586- 92.
Edelhoff D, Sorensen JA. Tooth structure removal associated with various preparation designs for posterior teeth. International Journal of Periodontics and Restorative Dentistry. 2002;22(3):241-50.
Zhang Y, Chai H, Lee J-W, et al. Chipping resistance of graded zirconia ceramics for dental crowns. Journal of dental research. 2012;91:311-5.
Passos SP, Nychka JA, Major P, et al. In Vitro Fracture Toughness of Commercial Y‐TZP Ceramics: A Systematic Review. Journal of Prosthodontics. 2015;24:1-11.
Stambaugh RV, Wittrock JW. The relationship of the pulp chamber to the external surface of the tooth. The Journal of prosthetic dentistry. 1977;37:537-46.
Kelly JR. Clinically relevant approach to failure testing of all-ceramic restorations. The Journal of prosthetic dentistry. 1999;81:652-61.
Rosentritt M, Behr M, van der Zel JM, et al. Approach for valuating the influence of laboratory simulation. Dental materials. 2009;25:348-52.
Schriwer C, Skjold A, Gjerdet NR, et al. Monolithic zirconia dental crowns. Internal fit, margin quality, fracture mode and load at fracture. Dental Materials. 2017.
Cavanaugh J. Encyclopedia of Statistical Sciences. Taylor & Francis; 2007.
Kirkpatrick LA, Feeney BC. A simple guide to IBM SPSS: for version 20.0: Nelson Education; 2012.
Scherrer S, De Rijk W. The fracture resistance of allceramic crowns on supporting structures with different elastic moduli. International Journal of Prosthodontics. 1993;6(5).
Kelly JR, Campbell SD, Bowen HK. Fracture-surface analysis of dental ceramics. The Journal of prosthetic dentistry. 1989;62:536-41.
Burke F. Maximising the fracture resistance of dentinebonded all-ceramic crowns. Journal of dentistry. 1999;27:169-73.
Lia ZC, White SN. Mechanical properties of dental luting cements. The Journal of prosthetic dentistry. 1999;81:597- 609.
Jalalian E, Atashkar B, Rostami R. The effect of preparation design on the fracture resistance of zir-conia crown copings (computer associated design/computer asso-ciated machine, cad/cam system). Journal of Dentistry of Tehran University of Medical Sciences. 2011;8:123-9.
Borba M, de Araújo MD, Fukushima KA, et al. Effect of the microstructure on the lifetime of dental ceramics. dental materials. 2011;27:710-21.
Rekow E, Silva N, Coelho P, et al. Performance of dental ceramics: challenges for improvements. Journal of Dental Research. 2011;90:937-52.
Preis V, Behr M, Hahnel S, et al. In vitro failure and fracture resistance of veneered and full-contour zirconia restorations. J Dent. 2012;40:921-8.
Bomicke W, Rues S, Hlavacek V, et al. Fracture Behavior of Minimally Invasive, Posterior, and Fixed Dental Prostheses Manufactured from Monolithic Zirconia. J Esthet Restor Dent. 2016;28:367-81.
Partiyan A, Osman E, Rayyan MM, et al. Fracture resistance of three-unit zirconia fixed partial denture with modified framework. Odontology. 2017;105:62-7.
Amaral M, Villefort RF, Melo RM, et al. Fatigue limit of monolithic Y-TZP three-unit-fixed dental prostheses: Effect of grinding at the gingival zone of the connector. Journal of the Mechanical Behavior of Biomedical Materials. 2017;72:159-62.
Anderson D. Measurement of stress in mastication. I. Journal of Dental Research. 1956;35:664-70.
Gibbs CH, Mahan PE, Mauderli A, et al. Limits of human bite strength. The Journal of prosthetic dentistry. 1986;56:226-9.
Helkimo E, Carlsson GE, Helkimo M. Bite force and state of dentition. Acta odontologica scandinavica. 1977;35:297- 303.
Waltimo A, Kemppainen P, Könönen M. Maximal contraction force and endurance of human jaw‐closing muscles in isometric clenching. European Journal of Oral Sciences. 1993;101(6):416-21.
Kober K, Ludwig K. Maximale Kauraft als Berechnungsfaktor Zahntechinischer Konstrutionen. Dent Lab. 1983;31:55-60.
Castellani D, Baccetti T, Giovannoni A, et al. Resistance to fracture of metal ceramic and all-ceramic crowns. International Journal of Prosthodontics. 1994;7.
Kappert H, Knode H. In-Ceram: testing a new ceramic material. Quintessence Dent Technol. 1993;16:87-97.
Geis-Gerstorfer J, Fässler P. UNTERSUCHUNGEN ZUM ERMUDUNGSVERHALTEN DER DENTALKERAMIKEN ZIRKONDIOXID-TZPUND INCERAM. Deutsche Zahnärztliche Zeitschrift. 1999;54:692- 4.
Onodera K, Sato T, Nomoto S, et al. Effect of connector design on fracture resistance of zirconia all-ceramic fixed partial dentures. The Bulletin of Tokyo Dental College. 2011;52:61-7.
Filser F, Kocher P, Weibel F, et al. Reliability and strength of all-ceramic dental restorations fabricated by direct ceramic machining (DCM). International journal of computerized dentistry. 2001;4:89-106.
Raigrodski AJ, Saltzer AM. Clinical considerations in case selection for all-ceramic fixed partial dentures. Practical procedures & aesthetic dentistry: PPAD. 2001;14:411-9.