Comparison of Fracture Strengths among different Commonly Placed Anterior Esthetic Restorations for Primary Dentition: An in vitro study

The purpose of this study was to determine and compare the shear force (N) required to fracture or dislodge an all-ceramic zirconia-based crown using different luting cement with those of polycarbonate crown and strip crown for the primary anterior teeth in vitro. Study design: Four groups of esthetic restoration for primary anterior teeth were tested for fracture strength: 1) Fifteen all-ceramic zirconia-based crowns cemented with glass ionomer cement, 2) Fifteen all-ceramic zirconia-based crowns bonded with a self-adhesive resin cement, 3) Fifteen polycarbonate crowns cemented with a polymer reinforced zinc-oxide eugenol and 4) Fifteen resin strip crowns. All restorations were placed and cemented on reproductions of dies in an independent laboratory at Delhi, India. All samples underwent loading until fracture or dislodgement with the Universal Testing Machine. The force in Newton (N) required to produce failure was recorded for each sample and the type of failures was also noted and characterized. One-way analysis of variance (ANOVA) test and the Tukey and Scheffe’s post hoc comparisons were used for statistical analyses. Results: In this invitro study, results were measured in Newtons (N). Group 1 (410.9±79.5 N) and Group 2 (420.5±57.8 N) had higher fracture strength than Group 3 (330.3±85.6 N) and Group 4 (268.4±28.2 N). These differences were statistically significant at P≤.05 among the sample groups. No significant difference was found between groups 1 and 2 (P = 0.984) nor between groups 3 and 4 (P =0.104). Among type of failures, majority of restoration fractures for zirconia-based crowns and resin strip crowns were due to cohesive failures and polycarbonate crowns had predominantly mixed failures. Conclusions: Under the limitations of this in vitro study, it could be concluded that all-ceramic zirconia-based crowns attained the highest fracture strength among all restorative samples tested regardless of the type of luting agent employed (P<.01). Cohesive failures were commonly observed in the zirconia crowns and resin strip crowns, whereas polycarbonate crowns revealed predominately mixed failures

Fracture strength; Esthetic restorations; Primary teeth; Full coverage crown

1. Tinanoff N, O’sullivan DM. Early childhood caries: overview and recent findings. Pediatr dent: 19:12-6, 1997.

2. Roberts C, Lee JY, Wright JT. Clinical evaluation of and parental satisfaction with resin-faced stainless steel crowns. Pediatr Dent 23(1):28-31, 2001.

3. Waggoner WF. Anterior crowns for primary anterior teeth: An evidencebased assessment of the literature. Eur Arch Paediatr Dent 7(2):53-7. 2006.

4. Shah PV, Lee JY, Wright JT. Clinical success and parental satisfaction with anterior preveneered primary stainless steel crowns. Pediatr. Dent. 2004 26(5):391–395,2004.

5. Lee J K. Restoration of primary anterior teeth: review of the literature. Pediatr Dent 24(5):506-510, 2002.

6. Venkataraghavan K, Chan J, Karthik S. Polycarbonate crowns for primary teeth revisited: Restorative options, technique and case reports. J Indian Soc Pedod Prev Dent 32:156-9, 2014.

7. Waggoner WF. Restoring primary anterior teeth: updated for 2014. Pediatr Dent 37(2):163–170,2015.

8. Kupietzky A., Waggoner WF., Galea J. Long-term photographic and radiographic assessment of bonded resin composite strip crowns for primary incisors: Results after 3 years. Pediatr Dent 27(3):221–225, 2005.

9. Ashima G, Sarabjot KB, Gauba K, Mittal HC. Zirconia crowns for rehabilitation of decayed primary incisors: an esthetic alternative. Journal of clinical pediatric dentistry :39(1):18-22, 2014.

10. Larsson C., Zirconium dioxide based dental restorations. Studies on clinical performance and fracture behaviour. Swed Dent J Suppl.(213):9-84, 2011.

11. Ritchie RO. Mechanism of fatigue-crack propagation in ductile and brittle solids. International Journal of Fracture.; 100: 55–83,1999.

12. Waggoner WF, Cohen H: Failure strength of four veneered primary stainless steel crowns. Pediatr Dent 17:36-40,1995.

13. Planells del Pozo P, Fuks AB. Zirconia crowns—an esthetic and resistant restorative alternative for ECC affected primary teeth. J Clin Pediatr Dent 38(3):193–195,2014.

14. Vignesh KC, Kandaswamy E, Muthu MS. A Comparative Evaluation of Fracture Toughness of Composite Resin vs Protemp 4 for Use in Strip Crowns: An In Vitro Study. Int J Clin Pediatr Dent :13(1):57–60,2020.

15. Yilmaz A. A comparison of two different methods and materials used to repair polycarbonate crowns. The Journal of Contemporary Dental Practice 8(2):105-112, 2007.

16. Al Shobber MZ, Alkhadra TA. Fracture resistance of different primary anterior esthetic crowns. Saudi Dent J. 29(4):179-184. 2017.

17. Walia T., Salami A.M., Bashiri R., Hamoodi O.M., & Rashid, F. A randomised controlled trial of three aesthetic full-coronal restorations in primary maxillary teeth. Eur J of Paediatr Dent 15 (2):113-8,2014.

18. Palacios, R P, Johnson, G H, Phillips, K M, et al. (2006). Retention of zirconium oxide ceramic crowns with three types of cement. The Journal of prosthetic dentistry 96(2): 104-114,2006.

19. Wahadni Al, Hussey, A M, Grey, D L, N, et al. Fracture resistance of aluminium oxide and lithium disilicate-based crowns using different luting cements: an in vitro study. The journal of contemporary dental practice 10(2): 51-58. 2009.

20. Román-Rodríguez JL, Fons-Font A, Amigo-Borras V, Granell-Ruiz M, Busquets-Mataix D, Panadero RA, Solá-Ruiz MF. Bond strength of selected composite resin-cements to zirconium-oxide ceramic. Med Oral Patol Oral Cir Bucal. 1;18(1):e115-23,2013.

21. GottiG., GoracciC., García-godoy F., Ferrari M. Evaluation of the bonding mechanism of an adhesive material to primary teeth. J Dent Child;71(1):54-60,2004.

22. Alves ML, Campos F, Bergoli CD, Bottino MA, Özcan M, Souza RO. Effect of adhesive cementation strategies on the bonding of Y-TZP to human dentin. Operative dentistry;41(3):276-83, 2016.

23. Larabi H, Cetik S, Ha HT, Atash R.In Vitro Study of Bonding Strength of Zirconia on Dentin Using Different Adhesive Systems. Int J Prosthodont. 31(2):135-137, 2018.

24. Zhang Y, Kim J.W. Graded structures for damage resistant and aesthetic all-ceramic restorations. Dental Materials. 25(6): 781-790, 2009.

25. Heydari A, Nakhjavani YB, Anaraki EA, Arvan S, Shafizadeh M. Bite Force of 3-6-Year-Old Children After Unilateral Extraction of Primary Teeth. J Dent (Tehran) 15(1):47–53. 2018.

26. Owais AI, Shaweesh M, Abu Alhaija ES. Maximum occusal bite force for children in different dentition stages. The European Journal of Orthodontics 19;35(4):427-33, 2012.

27. Usui T,Uematsu S, Kanegae H, Morimoto T, Kurihara S Changes in maximum occlusal force in association with maxillofacial growth. Orthodontics and Craniofacial Research 10:226-234, 2007

28. Thompson GA. Determining the slow crack growth parameter and Weibull two-parameter estimates of bilaminate disks by constant displacement-rate flexural testing. Dent Mater 20:51–62,2004.

29. Aboushelib MN, Feilzer AJ, Kleverlaan CJ. Bridging the gap between clinical failure and laboratory fracture strength tests using a fractographic approach. Dental materials 25(3):383-91,2009.