Bond Strength and Deflection of Four Types of Bonded Lingual Retainers.

Amin Golshah,Shirin Asadian Feyli

doi:10.1155/2022/1707520

Abstract

Objectives This study aimed to assess the bond strength and deflection of four types of bonded lingual retainers. Materials and Methods In this in vitro, experimental study, 160 extracted, mandibular incisors were mounted in acrylic blocks in sets of two and randomized into four groups for bonding of 1.0.010 × 0.026-inch Bond-A-Braid®, 0.012 × 0.027-inch Retanium®TM, 0.038 × 0.016-inch Ortho FlexTech®, and 0.0175-inch three-strand retainer wires; 15 mm of passive wire was adhered to the lingual tooth surface using Transbond XT composite. The shear (SBS) and tensile (TBS) bond strength values were measured. The adhesive remnant index (ARI) score and deflection of wires were also determined under a stereomicroscope. Data were analyzed by the chi-square test and ANOVA. Results The four groups were significantly different regarding the ARI scores (P < 0.05). Significant differences were noted between the three-strand and all other groups in deflection (P < 0.05). The Retanium group had significant differences with other groups in peak SBS (P < 0.05). A significant difference was found between the Retanium and Ortho Flex groups in break SBS (P < 0.05). Significant differences were also reported between the three-strand and all other groups in peak TBS (P < 0.05). Conclusion The Retanium retainer had the maximum SBS, while the three-strand retainer had the maximum TBS. The three-strand and Retanium wires can probably better tolerate intraoral forces and have higher resistance to fracture due to having higher TBS. Also, the three-strand wire had lower deflection rate, which highlights its higher resistance to occlusal forces. Retanium and Ortho FlexTech wires had the most favorable failure modes.

Highlights

Maintaining the alignment of the teeth after orthodontic treatment is highly important [1]. e length of dental arch decreases, and the crowding of anterior teeth increases with aging [2, 3]. us, the use of permanent retainers appears to be the only way to maintain the ideal alignment of the teeth after orthodontic treatment [2, 3]
Bond Strength. e present results indicated that the Retanium retainer had the maximum shear bond strength (SBS) while the threestrand retainer had the maximum tensile bond strength (TBS)
The three-strand retainer had a TBS of 98.38 N, which was slightly different from the value reported by Samson et al [10], i.e., 107.17 MPa. is small difference can be due to different methodologies and use of different adhesives and composite resins. e SBS of BondA-Braid was found to be 56 N in both studies, which was significantly different from SBS of the three-strand retainer

Summary

Introduction

Maintaining the alignment of the teeth after orthodontic treatment is highly important [1]. e length of dental arch decreases, and the crowding of anterior teeth increases with aging [2, 3]. us, the use of permanent retainers appears to be the only way to maintain the ideal alignment of the teeth after orthodontic treatment [2, 3]. Maintaining the alignment of the teeth after orthodontic treatment is highly important [1]. Us, the use of permanent retainers appears to be the only way to maintain the ideal alignment of the teeth after orthodontic treatment [2, 3]. Several factors are responsible for unwanted tooth movement after orthodontic treatment such as regeneration of periodontal tissue [4], changes related to growth and development after treatment [5], and type of treatment performed [6]. To prevent unwanted tooth movements, retainer wires are connected to the lingual surface of the maxillary and mandibular incisors [1]. Lingual retainers should be flexible and have high bond strength and optimal resistance against unwanted deflection [10, 11]

Methods

Results

Conclusion