Influence of different tooth preparation and bonding techniques on the fracture resistance of tooth fragment reattachment

Figures & data

Table 1. Materials names, composition, manufacturer and batch numbers.

Material	Composition	Manufacturer	Batch no
Single bond^TM Universal Adhesive	Universal Adhesive: MDP Phosphate Monomer, Dimethacrylate resins, HEMA, VitrebondTM Copolymer, Filler, Ethanol, Water, Initiators, Silane. (pH 2.7)	3M ESPE. (St. Paul, MN 55144-1000, USA)	N489945
Filtek^TM Z250 XT Nano-hybrid universal resin composite	BIS-GMA, UDMA, BIS-EMA, PEGDMA, TEGDMA, combination of surface modified zirconia/silica and 20 nm particles. Filler loading 82%weight (60% by volume)	3M ESPE. (St. Paul, MN 55144-1000, USA)	NA28405
Filtek^TM Supreme Ultra Flowable Restorative	Bis-GMA, TEGDMA and Procrylat resins. Ytterbium trifluoride filler (0.1 to 5.0 microns), a non-agglomerated/non-aggregated surface-modified 20 nm and 75 nm silica filler, and a surface- modified aggregated zirconia/silica cluster filler (comprised of 20 nm silica and 4 to 11 nm zirconia particles). The aggregate has an average cluster particle size of 0.6 to 10 microns. The inorganic filler 65% by weight and 46% by volume).	3M ESPE. (St. Paul, MN 55144-1000, U.S.A.)	N664994
Meta etchant gel	37% phosphoric acid in water, thickening agent and colorants (pH = 0.5)	Meta Biomed, Germany	MET1906071

MDP: methacryloyloxydecyl dihydrogen phosphate HEMA: Hydroxyethylmethacrylate BIS-GMA: Bisphenol-A-diglycidylmetharylate TEGDMA: Triethyleneglycol dimethacrylate UDMA: Urethane dimethacrylate BIS-EMA: Ethoxylated bisphenol-A glycol dimethacrylate PEGDMA: Polyethylene glycol dimethacrylate.

Figure 1. (a) Specimen attached to a universal testing machine; (b) a chisel delivers the force 2 mm from the incisal edge.

Table 2. The mean, standard deviation (SD) values of fracture strength of different groups.

Variables	Fracture strength (KgF)
	Mean	SD	Fracture strength recovery %**
Group A: Intact tooth	76.92^a	3.74	100%
Group B: Cured bond + Flowable composite	32.08^c	4.76	41.7%
Group C: Uncured bond + Flowable composite	39.12^c	4.51	50.85%
Group D: Bevel + bond + Flowable composite.	37.25^c	5.20	48.42%
Group E: Over contouring + bond + Nanohybrid composite	52.65^b	2.74	68.44 %
Group F: Over contouring + bond + flowable composite	34.83^c	3.52	45.28%
p-value	<0.001*

*significant (p < .05) ** Fracture strength recovery was calculated based on the mean and SD of the fracture strength of sound teeth (100%).

Figure 2. Failure mode percentage in different groups.