Fiber-reinforced composites as the 4th generation bonded retainers in orthodontics

The enigma of relapse has prevailed in orthodontics since early 1900s. Good stability of an orthodontic treatment relies on proper planning of retention protocol. Many retention protocols are in use by various clinicians, the most common being fixed lingual retainers since the degree of relapse is highly unpredictable. Bonded retainers offer advantages compared to conventional removable retainers in that they are invisible from the front, require less patient cooperation, and provide a long-term or even permanent retention. Various techniques of fixed bonded retainers with different materials have been described in the literature. Glass fiber retainers were introduced to replace the conventional metal wires as fixed lingual retainers. They were proposed to provide better esthetics, easy handling, and biocompatibility as well as improved mechanical strength required for retention. The clinical reliability of Fiber Reinforced Composite retainers still remains questionable and its popularity as the "4th Generation" retainers is limited. The purpose of this paper is to review the rationale of the use of fiber reinforced composites as lingual retainers. Their clinical efficacy, success rate as well as periodontal and oral hygiene status has been discussed. Conclusion: Bonded fiber reinforced lingual retainers cannot be presently considered as the "4th generation." Despite being more esthetic, biocompatible and better retentive strength, the glass fiber retainers are more technique sensitive, expensive and have questionable clinical effectiveness. The multistranded or twisted stainless steel and other wire retainers still are most commonly and widely used.