From Volume 16, Issue 3, July 2023 | Pages 147-150
‘Wire syndrome’ is a phenomenon that involves fixed orthodontic retainers causing unwanted tooth movement. In severe cases, the retainer may have debonded from the teeth. This article addresses the prevalence, presentation and management of wire syndrome.
CPD/Clinical Relevance: This article is relevant for general dental practitioners, periodontists and orthodontists to recognize the signs of wire syndrome and understand its multidisciplinary management.
Fixed orthodontic retention has become an increasingly popular method of preventing occlusal relapse following orthodontic treatment.1 Wire syndrome is a term that was first coined by Roussarie et al.2 While this was a new phrase, the concept of wire syndrome has been widely known since it was described in detail by Katsaros et al.3
Unwanted tooth movement as a result of wire syndrome can often have periodontal implications because of marked gingival recession, as well as iatrogenic implications, such as torquing a root out of bone and losing the vitality of teeth. These tooth movements must not be confused with relapse of orthodontic correction, because the position of the teeth following wire syndrome is markedly different to the original tooth position.
As the number of patients attending general dental practices with retainer issues is increasing, awareness of wire syndrome and the effects of active bonded wires is rising. There are many clinicians however, who are still unaware of the adverse effects of orthodontic retainers becoming ‘active’ A survey carried out in France in 2021 described only 18% of general dental practitioners as being aware of the risks of placing an active bonded retainer.4 This article aims to educate general dental practitioners, orthodontists and periodontists about the phenomenon known as wire syndrome, and its management.
The prevalence of wire syndrome is widely debated in the literature. The lowest prevalence reported was 1% in a study with 3500 participants.5 The highest prevalence described was 43%, although only 30 participants were included in this particular study.6
Many different types of wires are used for orthodontic retainers. It has been suggested that wire syndrome most commonly occurs with round, twisted, stainless steel wires;2 however, Roussarie and Douady stated that any wire can cause wire syndrome, and that it is not more prevalent with one wire compared to another.7
Table 1 describes some of the most common materials used for fixed retention.
| Wire type | Material | Product market name |
|---|---|---|
| Flat braided chain | Stainless steel | Ortho Flextech (Reliance Orthodontic Products, USA) |
| Single wire | Stainless steel | Perform co-axial archwire (Ortho-Care, UK) |
| Round twisted wire | Stainless steel | Twistflex/Supra-Flex (Eurodontic Ltd, UK) |
| Rectangular wire (milled CAD/CAM) | Nitinol | Memotain (Ormco International, UK) |
There are two main theories about wire syndrome and how it causes these adverse effects on the dentition and the surrounding gingival apparatus.
The first theory relates to procedural errors on placement of the bonded wire. The second theory relates to a break in the bond between the wire and the adhesive, leading to rotation of the wire, exerting force that can cause unwanted tooth movement.7
The first theory discusses the bonding technique used to place the wire. If an indirect bonding technique has been used, whereby an impression is taken for a wire to be fabricated in the laboratory, there can be issues at the fitting appointment. For example, the teeth may have moved slightly since the impression was carried out. There may also have been mistakes during the impression, or during the casting process. It has been suggested that in order to prevent any issues during casting, the impression must be cast within 45 minutes of taking the impression.7 An alternative would be to take a digital impression, which is becoming increasingly common, and this may overcome impression-taking problems.
Incorrect bending of the wire can also lead to it becoming active. It is important to bend the wire beyond its elastic limit to ensure permanent deformation, or to anneal the wire after forming to reduce the potential for tooth movement. With a direct bonding technique, the use of elastics to aid placement of the retainer could lead to the wire becoming active if it has not been annealed. When placing the wire, it needs to be placed passively without any unwanted force exerted on the teeth.
The second theory relates to breaking of the bond between the wire and adhesive, which is assumed to be caused by external forces. The teeth remain connected to the wire, but the bond between the wire and adhesive breaks. The maximum chewing force at the incisor region is 113N.8 Palatal-bonded retainers are subject to greater forces during mastication than lingual retainers, so are at greater risk of deformation. Torsion of the teeth occurs around the wire, which then acts as the centre of rotation.9,10 This could be an explanation for unwanted torquing of the teeth occurring in wire syndrome cases.
Wire syndrome leads to unwanted and unexpected tooth movement. Teeth can be displaced in all three planes of space. Wire syndrome can lead to a median range of tooth movement of 0–0.66 mm.1 It is important to review both pre-treatment photos and photos following debonding of appliances to determine whether tooth movements are caused by orthodontic relapse or are a result of wire syndrome.
Extreme wire syndrome can lead to the root being torqued out of the alveolar bone, leading to gingival recession. This also puts pressure on the neurovascular bundle, resulting in loss of vitality.3
Gingival recession can be defined as an ‘apical shift of the gingival margin with subsequent exposure of the root surface’.11 The pathogenesis of gingival recession can be induced by bacteria or trauma.12 The first effect of subgingival plaque is formation of a gingival pocket. If the gingiva is thin, the entire connective tissue layer may be affected by the inflammatory process induced by the subgingival bacteria plaque. As a result, the gingival margin lacks support and recedes apically. The pathogenic mechanism is described as centrifugal because it acts from the inside to the outside.
When the recession is induced by trauma, the pathogenesis is almost opposite. The aetiological agent acts on the external gingival surface initially, causing gingival abrasion. As the stimulus continues, the sum of direct trauma-induced tissue damage, as well as damage from the inflammatory lesion secondary to the trauma, destroys the gingival connective tissue, creating a gingival ulcer. When the entire thickness of the gingival connective tissue is involved, a root dehiscence is created. This pathological mechanism is described as centripetal because it acts from the outside toward the inside.
Both mechanisms may be relevant in wire syndrome. Typically, trauma may occur through overzealous brushing and bacteria through suboptimal plaque control. As well as these precipitating factors, there are notable predisposing factors.
A key predisposing soft tissue feature for gingival recession is a thin phenotype. These patients have a more delicate type of gingivae, so will be more prone to developing recession. Other soft tissue factors include a high frenal attachment and a shallow vestibular depth. Hard tissue factors include thin buccal bone, as well as a dehiscence or fenestrations of the root surface. The tooth position within the arch following movement is also relevant, as is the discrepancy in the size of the root compared to the width of the alveolus.
Figure 1 shows a clinical case of wire syndrome in a 44-year-old male patient who presented with concerns over progressive recession. He had undergone two courses of orthodontic therapy, once in adolescence and a second round in his mid-twenties; both using fixed appliances. A twisted wire retainer had somehow activated, leading to torquing of the LR3 and LL1 roots buccally, with significant recession and loss of keratinized gingiva.
If a bonded retainer fractures, it should be replaced with a new passive retainer. If the wire is just pushed to fit the tooth surface better, this may lead inadvertently to creating an active wire.2 A key element in the prevention of wire syndrome is, therefore, close monitoring of both retainer integrity and tooth position. This may involve reviewing clinical photography or sequential intra-oral scanning, which may also help detect early unwanted tooth movement.
If a root has been torqued through the buccal bone, positive lingual root torque can be placed within an archwire to move the root back into its original position. This may require working through an archwire sequence, finally expressing full lingual root torque in heavy rectangular stainless steel archwires, for example, with the use of a 19 x 25 stainless steel archwire or the use of a torquing auxiliary, which can be technically demanding.
Correcting the root position can increase the success rate and predictability of resolving a recession defect. As movement of an individual tooth with orthodontic fixed appliances is difficult, altering root position often involves placing a full arch fixed appliance, as well as possible placement of a fixed appliance on the opposing arch to ensure a good occlusion at the end of treatment, which obviously increases the cost of treatment.
A novel orthodontic device that aims to focus tooth movement on the affected buccally placed teeth has been described in the literature. This technique demonstrates promise from its initial case series, but requires further clinical evidence before becoming a mainstream approach.13
When it comes to deciding how to manage the gingival recession, it is often sensible to give preventive advice and consider monitoring for progress before deciding whether intervention is justified. In these cases, oral hygiene techniques need to be gentle, but thorough, to prevent further recession. There are two key indications for active surgical intervention: if the patient has aesthetic concerns, or for the prevention of continued recession. If orthodontic alignment was going to be performed, this would need to occur prior to any surgery to ensure that the root would be in the most optimal position in the bone. Movement of the root lingually can also be accompanied by improvements in the quality and quantity of the gingival tissue associated with the recession defect, which has two benefits:
When there are no aesthetic concerns, and the aim is to produce a thicker keratinized tissue to prevent progression of the recession and allow the patient to clean the area comfortably, a free gingival graft would be a predictable option. A free graft is one that has been removed from its blood supply and transferred to a remote site. The recipient site is prepared by means of a split thickness flap, then a matching sized piece of graft is harvested from the palate and secured in place and allowed to heal.
Where root coverage is the aim, there are a number of pedicle soft tissue graft procedures that might be considered. The most common is the coronally advanced flap, based on a coronal shift of the soft tissues on the exposed root surface, with or without a connective tissue graft. The most recent version of this technique is using a trapezoidal flap design and a split–full–split-thickness flap elevation approach.14
Other variants of a pedicle flap can be applied to recession cases based on the clinical presentation including, but not limited to:
Wire syndrome is a complication of orthodontic treatment, with no definitive explanation as to its cause. Two theories have been proposed: either errors during placement of a bonded retainer, or rotation of a tooth between the wire and adhesive if the bond is broken.
Management of recession will ideally involve a multidisciplinary approach involving both orthodontists and periodontists, with corrective orthodontic tooth movement being an important consideration for success.
