Orthodontics and Neuromuscular Orthopedics

T. Henrikson and M. Nilner (Malmö University, Sweden)
T. Henrikson, Department of Orthodontics, Faculty of Odontology, Malmö University, Carl Gustafs väg 34, S-205 06 Malmö, Sweden.

Journal of Orthodontics, Vol. 30, No. 2, 129-137, June 2003.

This paper is review of three published papers that was presented at the British Orthodontic Society Spring meeting at Heythrop Park in May 2001. The material in this publication is used by permission of Oxford University Press and Swedish Dental Journal.

The following is a section of the complete article.

ABSTRACT

Objectives: To prospectively and longitudinally study symptoms and signs of temporomandibular disorders (TMD) and occlusal changes in girls with Class II malocclusion receiving orthodontic fixed appliance treatment in comparison with untreated Class II malocclusions and with normal occlusion subjects.

Design: Prospective observational cohort.

Subjects: Sixty-five girls with Class II malocclusion who received orthodontic treatment, 58 girls with no treatment, and 60 girls with normal occlusion.

Method: The girls were examined for symptoms and signs of TMD and re-examined 2 years later. Additional records were taken in the orthodontic group during active treatment and 1 year after treatment

Results: All three groups included subjects with more or less pronounced TMD, which showed individual fluctuation during the ongoing study. In the orthodontic group, the prevalence of muscular signs of TMD was significantly less common post-treatment. Temporomandibular joint clicking increased in all three groups over the 2 years, but was less common in the normal group. The normal group also had a lower overall prevalence of TMD than the orthodontic and the Class II group at both registrations. Functional occlusal interferences decreased in the orthodontic group, but remained the same in the other groups over the 2 years.

Conclusions: (i) Orthodontic treatment either with or without extractions did not increase the prevalence or worsen pre-treatment symptoms and signs of TMD. (ii) Individually, TMD fluctuated substantially over time with no predictable pattern. However, on a group basis, the type of occlusion may play a role as a contributing factor for the development of TMD. (iii) The large fluctuation of TMD over time leads us to suggest a conservative treatment approach when stomatognathic treatment in children and adolescents is considered.

INTRODUCTION
Symptoms and signs of temporomandibular disorders (TMD) are relatively common in children and adolescents.⁴ These can appear, increase in frequency and severity during the second decade of life.^5,6 Importantly, about 30 per cent of the population of children and adolescents receive orthodontic treatment in most western European countries during this period. This has, arguably, led to claims that orthodontic treatment is a risk factor for the development of TMD have appeared in the literature.^7–11 These claims have been questioned and discussed in recent literature reviews.^12,13 However, previous studies analysing the role of orthodontic treatment in relation to TMD have often included large age variations and different malocclusions, both in the orthodontic treatment group and, if present, in the control group. Therefore, there is a need for controlled studies to further investigate the relationship between orthodontic treatment and TMD, especially since this relationship still is under debate.

In view of the high prevalence of symptoms and signs of TMD in children and adolescents, it is likely that patients receiving orthodontic treatment could experience TMD before, during, or after their orthodontic treatment.

Results

Clinical findings
Clinical signs of TMD and functional occlusal interferences. The prevalence of clinical signs of TMD at the start and after 2 years is presented in Table 1. In the normal group, the overall prevalence of signs of TMD was numerically lower than in the other two groups at both registrations. The general trend was an increased prevalence of signs of TMD over the 2 years. Exceptions to this trend were found in the Orthodontic group, where the prevalence of pain on maximal mandibular movements (P = 0.03) and muscle tenderness to palpation grade 2–3 (P = 0.004) decreased significantly over the 2 years. All three groups had an increased prevalence of TMJ clicking over the 2 years. Only two subjects had reciprocal clicking at both the first and second registration, and no subject developed a closed lock during the 2-year period.

Conclusions
In the individuals, symptoms and signs of TMD and TMD diagnoses fluctuated substantially over time with no predictable pattern. On a group basis, the type of occlusion may play a role as a contributing factor for the development of symptoms and signs of TMD, although this influence is difficult to quantify and predict.

Orthodontic treatment with fixed appliance either with or without tooth extractions did not increase the prevalence of symptoms and signs, or worsen pre-existing symptoms and signs of TMD. Subjects with Class II malocclusion and pre-existing signs of TMD of muscular origin seemed to benefit functionally from orthodontic treatment in a 3-year perspective.

One orthodontic treatment effect when normalizing Class II malocclusions with fixed appliances was a decreased prevalence of functional occlusal interferences, while the changes in subjects with untreated Class II malocclusion and normal occlusion were minor.

This encouraged us to carry out a series of prospective studies to study symptoms and signs of (TMD), and occlusal changes in girls with Class II malocclusion receiving orthodontic treatment in comparison with untreated Class II malocclusions and with normal occlusion subjects.

Filed under: Orthodontics and Occlusion, Orthodontics and TMJ/TMD by clayton@drclaytonchan.com
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