Effect of orthodontic adhesive thickness on force required by debonding pliers

Abstract

This in vitro study evaluated the relationship between removal force and the thickness of three orthodontic adhesives, namely, light-and chemical-cured resin cements and a resin-modified glass ionomer cement. The thickness of each adhesive was 50, 100, 150, or 200 µm, and all adhesives were bonded on bovine incisors. Removal force was measured before (TC-0) and after 1,000 thermal cycles (TC-1000), and values were compared. At TC-0, the removal strengths for adhesive thicknesses of 50 and 100 µm were significantly lower than those for thicknesses of 150 and 200 µm (P < 0.05). At TC-1000, removal strengths for adhesive thicknesses of 50 and 100 µm were also significantly lower than those for 150 and 200 µm. Superbond Orthomite specimens showed a significant difference in removal strength between TC-0 and TC-1000 (P < 0.05) at all thicknesses. There was no significant difference in the distribution of adhesive remnant index scores at any thickness. These findings indicate that decreasing the thickness of applied orthodontic adhesive reduces the removal strength required. (J Oral Sci 56, [185][186][187][188][189][190] 2014)

Shear bond strength and debonding characteristics of a new premixed self-etching with a reference total-etch adhesive

“…All donor animals were aged between 2 and 5 years. The use of bovine incisors for in vitro tests has already been widely performed in earlier studies and was found to be comparable to human teeth [ 17 , 24 , 25 ]. All teeth were stored in 0.5 % chloramine-T solution for in between 1 week and 6 months, according to the German DIN 1399-1:2009-05.…”

Effect of thermal cycling on the shear bond strength of different orthodontic adhesives to enamel

“…However different findings were noted in other studies involving G and TP group 5,16,17,20,21 whereas different amounts of adhesive were recorded on the enamel surface after bond strength tests. Group ED achieved score 1 without effect of thermal cycling.…”

“…7 The balance between bond strength of the adhesive to enamel and enamel damage is the main key to obtain successful results in an orthodontic treatment regarding the procedure of bracket bonding. 21 Also, results revealed a tendency for thermal cycled specimens to exhibit lower bond strength values together with higher percentage of adhesive remnants on the enamel surface. This might be explained by the detrimental effect of the thermal cycling on the interface between adhesive and the bracket base.…”

“…8,15 However, the thickness of the adhesive is not the same considering variations related to the operator technique, materials' properties and geometry of the teeth surfaces. 8,15,21 It is noteworthy to highlight the lack of connection between the bracket base and the adhesive, when compared to the good adhesive -enamel interface. The negative effects of these microgaps, as discussed above, can be addressed by a surface treatment on the bracket base allowing the establishment of a satisfactory bond between the two materials.…”

“…Previous studies have reported different results considering the effect of thermal cycling on shear bond strength for such compomer -based adhesive. 14,21 For instance, a previous study revealed stable shear bond strength of orthodontic adhesives to enamel after thermal cycling between 5 and 60 o C although samples were tested only for 500 cycles. 14 Another previous study reported a decrease in shear bond strength after 1000 thermal cycles between 4 and 60 o C. Concerning the performance of the materials in oral cavity, additional tests must be performed for longer period of thermal cycling to simulate the orthodontic treatment time.…”