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An unusual presentation of dental transposition caused by digit-sucking

From Volume 13, Issue 1, January 2020 | Pages 20-24

Abstract

This article describes the case of a 12-year-old boy who presented with a unique digit-sucking habit which has led to transposition of the lower lateral incisors with the lower canines. The aetiology, pathology and management are described for digit-sucking habits and dental transposition.

CPD/Clinical Relevance: It is important to recognize digit-sucking habits in patients and the implications for the malocclusion.

Article

Inderjit Shargill

The development of facial and dental structures are dependent on genetic and environmental factors.1 The effects of environmental factors can be more severe the earlier the interaction with the dento-facial complex occurs. Early digit-sucking habits can influence development of the occlusion and several studies have suggested that prolonged digit-sucking can lead to anterior open bites, posterior crossbites, proclination of the upper incisors and retroclination of lower incisors (Table 1).2,3,4,5,6 It is theorized that, during prolonged thumb-sucking, the tongue is depressed. This change in the balance of forces between the tongue and the cheeks, in addition to the negative pressure caused by the sucking action, can cause constriction of the upper arch form, leading to posterior crossbites. Prolonged digit pressure leads to intrusion and proclination of the upper incisors and retroclination of the lower incisors. The effect is often characterized by an asymmetric anterior open bite, depending on the digit that is being sucked (Figure 1).


Area of Effect Effect
Vertical changes Decrease in overbite Anterior open bite
Anterior posterior changes Increase in overjet
Upper incisors Proclination Intrusion
Lower incisors Retroclination or proclination depending on position of digit
Molar relationship Class II molar relationship
Transverse Unilateral buccal crossbite
Other Associated with root resorption
Figure 1. Anterior open bite as a result of digit-sucking.

The prevalence of digit-sucking varies between 12% and 34% in 9-year-olds.7,8,9 There is very little literature on the prevalence of digit-sucking habit in the UK. A study undertaken in Kettering,10 reported that 23.6% reported a history of a habit and 12.1% reported a prolonged habit past the age of 7 years old. Management of a digit-sucking habit is initially conservative11 (Table 2). It has been suggested that more than 6 hours per day digit-sucking can lead to significant malocclusion.18 Placement of the digit can vary between children and, therefore, potentially a range of malocclusions can result. If intercepted early, the anterior open bite caused by the digit-sucking habit can resolve, but this can take several years.19


Prevention Encouragement of dummy-sucking rather than digit-sucking. Although, the effects to the deciduous dentition are more severe, the patients stop the habit earlier.8
Habit-breaking therapy
  • It must be the child that wishes to stop the habit;
  • Simply explaining the effect of the habit on the occlusion to the child and parents can lead to cessation of the habit.
    • Management strategies can be grouped into non-physical and physical methodsNon-physical methodsThese involve behaviour therapies which are in the area of clinical psychology:
  • Contingency management:
  • – Provision of positive reinforcement in the form of a reward upon reduction of habit.12
  • Habit reversal:
  • – The child is taught to carry out alternative activities when he/she feels the need to suck a digit.13–14
  • Reframing:
  • – Changing the context of the habit makes it more of a chore to continue the habit.15
    • Physical methods
  • Making the digit a less viable option:
  • – This can include painting the digit with an unpleasant tasting substance;
  • – Covering the digit with adhesive bandages.
  • Making the access to digits difficult:
  • –This can include wearing woolly gloves or sewing a glove to a pyjama top.
  • Intra-oral approach to make it difficult to prevent digit placement:
  • – An upper removable appliance, but it is dependent on patient compliance;
  • – A fixed appliance which normally consists of transpalatal arch design with extension inferiorly (Figure 2). This has been shown to be the most successful, but it can use compliance which might be required for orthodontic treatment.16–17
    		•
    Figure 2. Fixed habit-breaking appliance.

    Dental transpositions are rare dental anomalies, with a prevalence of 0.03% to 0.51%.20,21,22,23 A true transposed tooth can be defined as one which has changed positional location to an adjacent tooth, or the positional interchange of the roots of two adjacent teeth, and is erupting into a position normally occupied by a non-adjacent tooth.24 Pseudo-transposition is more common and occurs when the crowns of adjacent teeth have changed position but the roots have not.24 The evidence for the aetiology is poor, although it is suggested that there is a polygenic inheritance pattern which is supported by familial associations, associations with other dental anomalies (Table 3)25,26,27,28,29 and differences in sex and racial differences.30 Classification is based on jaw of occurrence, transposed tooth and site of transposition (Table 4).30 The most common transposition is the maxillary canine with the first maxillary premolar and this forms 71% of total transpositions.23


  • Dilacerations
  • Ankylosed teeth
  • Rotated teeth
  • Peg-shaped lateral incisors
  • Missing teeth
  • Retained teeth
  • Impacted wisdom teeth

    • Three part code:
  • Jaw of occurence;
  • Transposed tooth;
  • Site of transposition.
    		•
    Jaw and tooth codes:
  • Mx: maxilla
  • Mn: mandible
  • P1: first premolar
  • P2: second premolar
  • L1: central incisor
  • L2: lateral incisor
  • M1: first molar
  • M2: second molar
    		•
    For example: Mx.C.L2 is the transposition of the maxillary canine with the lateral incisor.

    Clinical implications of dental transpositions are mostly aesthetic but can also include interferences to static and dynamic malocclusion. Correcting transposed teeth is very difficult and therefore most management strategies would involve accepting the transposition (Table 5), or extracting one of the transposed teeth.


    Accept
    Restorative only option: camouflage the transposed teeth
    Orthodontic option that does not correct transposition:In case with crowding, the area of transposition can be decided as the extraction decision of choice
    Orthodontic option to correct transposition

    Case report

    A 12-year-old boy was referred by his General Dental Practitioner (GDP) to the Leeds Dental Institute Orthodontic department. His main presenting complaint was that he was unhappy with his teeth sticking out. The medical history was unremarkable. However, further questioning revealed that the patient sucked his digits while watching TV in a somewhat unique manner (Figure 3).

    Figure 3. Patient sucking his fingers.

    Extra-oral examination revealed a Class II skeletal pattern with normal vertical proportions (Figure 4). The patient presented with a Class II division 1 incisor relationship with an overjet of 10 mm and a decreased overbite (Figure 5). The lower arch had severe crowding, with the lateral incisors displaced distally and lingually, with severe displacement causing transposition and the lower canines to erupt into the space of the lateral incisors (Figure 6). This was further confounded by occlusal interferences by teeth in the upper arch with these lateral incisors. Radiographic examination confirms that this was a pseudo-transposition between the lower lateral incisor and lower canine (Mn.12.C) (Figure 7).

    Figure 4. Profile of patient.
    Figure 5. (a) Right intra-oral view; (b) anterior intra-oral view; (c) left intra-oral view.
    Figure 6. Intra-oral view of the lower arch.
    Figure 7. Dentopantograph.

    This appear to be due to the unusual digit-sucking habit of placement of the first and second finger on the lower arch. This has resulted in severe displacement of the lateral incisors during eruption and has caused transposition with the lower canine teeth (Figure 8).

    Figure 8. Placement of fingers during digit-sucking habit.

    This patient's malocclusion was further complicated by the Class II skeletal pattern with Class II division 1 incisor relationship and an overjet of 10 mm. It was important, however, to address the thumb-sucking habit first. Prior to starting any orthodontic treatment, habits have to be discontinued. This is important because any treatment undertaken without this will relapse and produce similar results in the malocclusion.

    Initially, conservative options were used: this included discussion with the patient and parent regarding the digit-sucking habit and its implications on the malocclusion and the rewarding of the patient when he was not sucking his digits. Upon review, this proved to be unsuccessful and it was suggested that the patient applied sticking plaster on his digits or wore a glove sewn to his pyjama top. Unfortunately, this also proved to be unsuccessful. Although the risks of a fixed habit-breaking appliance have the potential for non-compliance with future treatment, it was used following attempts at conservative options. After 6 months of wear, this treatment was successful and the patient stopped sucking his fingers.

    Conclusions

    Digit-sucking habits are relatively common in young children. In the small percentage of children that persist, it can lead to disruption of the malocclusion that characteristically leads to an anterior open bite due to intrusion of the incisors. However, placement of digit(s) in a particular area may lead to distortion of the developing arch form, which can lead to dental transposition as described in this case report.

    It is important to take a comprehensive dental history of all paediatric patients regarding relevant habits and to be able to recognize the intra-oral and extra-oral signs of these.