Objectives: To compare the costs and treatment effects of headgear activator treatment of Class II malocclusion with excessive overjet between treatments started in the mixed (MD) and late mixed dentition (LMD).

Trial design: Two-arm parallel-group single-centre randomized controlled trial (RCT).

Material and methods: A total of 56 children presenting Class II malocclusion with excessive overjet were assessed and invited to an RCT designed as intention-to-treat. The children were randomized, by an independent person not involved in the trial into two groups, treatment with headgear activator in the MD starting at the age of 9 or to treatment with a headgear activator in LMD, starting at the age of 11. The primary outcome measure was to compare the treatment costs between the two groups. Societal costs (the sum of direct and indirect costs) were calculated for successful treatments only and when unsuccessful treatments were included. Secondary outcomes were comparisons of oral health-related quality of life (OHRQoL), dental and skeletal treatment effects, lip closure, and trauma incidence. Data collections were performed before and after treatment, corresponding to a treatment period of 2 years. Blinding was accomplished when assessing outcomes.

Results: No group differences in costs were found of successful treatments or when unsuccessful treatments were included. The most pronounced treatment effects in both groups were the reduction of overjet and improved molar relation. Treatment started in MD or in LMD were equal and without significant differences regarding effects on OHRQoL, skeletal effects, lip closure, and incidence of trauma.

Harms: No harm was observed, but 8 of 30 children (27%) in the MD and 6 of 21 children (29%) in the LMD group showed unsuccessful results.

Limitations: Costs depend on local factors and can thereby not be directly transferred to other settings. It was a single-centre trial and can thus be less generalizable.

Conclusions: Regarding costs and treatment effects, there is no difference if headgear activator treatment of excessive overjet starts in the MD or LMD.

Clinical trial registration: NCT04508322.

OBJECTIVES: To compare early headgear activator treatment of Class II malocclusion with excessive overjet with untreated control subjects in terms of the primary outcomes overjet and overbite as well as the effect regarding oral-health-related quality of life (OHRQoL), lip closure, incidence of trauma, and skeletal changes.

TRIAL DESIGN: Two-arm parallel group single-centre randomized controlled trial.

MATERIAL AND METHODS: A total of 60 children (mean age 9.5 years) presenting a Class II malocclusion with excessive overjet were recruited. The trial was designed as intention-to-treat and the participants randomized by an independent person not involved in the trial to either early treatment with headgear activator or to an untreated control group (UG). Dental and skeletal variables as well as registrations of OHRQoL, lip closure, and incidence of trauma were recorded. For the treatment group, data were registered at baseline before treatment and when treatment was finished, corresponding to approximately 2 years. For the UG, registrations were made at baseline and at 11 years of age. Observers were blinded to treatment allocation when assessing outcomes.

RESULTS: Early treatment with headgear activator significantly decreased overjet and improved molar relationship when compared with untreated controls. The effects were primarily due to dentoalveolar changes. Early treatment had no evident effect regarding OHRQoL, lip closure, or incidence of trauma. Lack of cooperation resulted in unsuccessful treatments for 27% of the patients.

LIMITATIONS: The trial was a single-centre trial and can thus be less generalizable.

CONCLUSIONS: The main treatment effect of early headgear activator treatment of Class II malocclusion with excessive overjet is reduction of overjet.

TRIAL REGISTRATION: NCT04508322.

Class II malocclusion with excessive overjet is one of the most common malocclusions among children and adolescents. In addition to increasing the risk for dental trauma, the malocclusion can also be related to bullying due to the prominent maxillary incisors. The treatment for a Class II malocclusion can be initiated at different ages and with different treatment strategies, but the treatment timing has often been, and still is, discussed within the orthodontic profession and literature. Research reports that an early treatment approach, initiated in mixed dentition and often including an additional phase of treatment in permanent dentition, reduces the incidence of dental trauma. Otherwise, no differences in treatment effects have yet been seen between treatment that is started early in mixed dentition or treatment initiated later in permanent dentition. 

During the last decades, there has been an increased focus on patient-reported outcomes within orthodontic research. The patient perspective and economic evaluations of performed treatment are areas where knowledge gaps can be found in the available research. 

This thesis is based on four studies. The studies were designed with high level of methodology and validity as a priority and with the objective to identify and address knowledge gaps related to the impact of Class II malocclusion with excessive overjet and a subsequent early treatment with headgear activator. Firstly, a systematic review addressing treatment effects was performed. This was followed by the implementation of two randomised controlled trials (RCTs) with the aims to evaluate treatment effects and self-perceived oral health-related quality of life (OHRQoL) as well as the cost associated with treatment. In addition, a clinical controlled trial was performed to assess the self-perceived OHRQoL for children with Class II malocclusion with excessive overjet, and compare to children with unilateral posterior crossbite or normal occlusion with no or mild orthodontic treatment need.  

The papers referred to in this thesis:  

Paper I. A systematic literature review performed to evaluate the evidence supporting early treatment (before the age of 10) of Class II malocclusion. The search included four data bases and spanned from January 1960 to October 2017.  

Paper II. A clinical controlled multicenter trial with the objective to investigate the OHRQoL among 9-year-old children in mixed dentition and to compare the self-perceived OHRQoL by the use of the Child Perceptions Questionnaire (CPQ). Evaluation and comparisons were made for children with Class II malocclusion with excessive overjet (EO), children with unilateral posterior crossbite (UPC), and children with normal occlusion (NO) presenting with no or mild orthodontic treatment need.  The sample consisted of 229 children, sourced from 19 Public Dental Service Clinics in Sweden and covering a range of demographic areas.

A single centre RCT designed to evaluate the effects of headgear activator treatment and the associated costs forms the basis of the final two papers: 

Paper III. The effects of early headgear activator treatment was compared to an untreated control group. The sample consisted of 60 children presenting with a Class II malocclusion with excessive overjet. Primary outcome was the reduction of overjet and overbite as well as effects regarding oral health-related quality of life, lip closure, incidence of trauma, and skeletal changes.

Paper IV. The costs and treatment effects of headgear activator treatment started in the mixed or late mixed dentition was registered and compared. The sample consisted of 51 children starting treatment at 9 or 11 years of age. The primary outcome measure was comparison of the treatment costs between the two groups. Secondary outcomes were comparisons of oral health-related quality of life, dental and skeletal treatment effects, lip closure, and trauma incidence. 

The following conclusions were drawn: 

• There is medium to high level of evidence, depending on treatment appliance, that early treatment reduces overjet and improves antero-posterior skeletal relationship, but currently, insufficient evidence is available regarding the effects of early treatment on OHRQoL, incidence of trauma, soft tissue profile, or treatment-related costs. There is a knowledge gap with respect to long-term outcome and the stability of early treatment.
• Children with Class II malocclusion with excessive overjet report significantly lower self-perceived OHRQoL compared to children with unilateral posterior crossbite or normal occlusion, with the domains of social and emotional well-being being most affected. The children in all three groups reported generally low CPQ scores, which implies an overall fairly good self-perceived OHRQoL.
• Early treatment with headgear activator was successful in reducing overjet and correcting molar relationship. Early treatment did not result in any significant difference regarding self-reported OHRQoL, lip closure, or incidence of trauma when compared to the untreated control group.
• The costs associated with headgear activator treatment, as well as the treatment effects, were equivalent regardless of whether treatment was started at 9 or 11 years of age. The most pronounced treatment effects were reduction of overjet and correction of molar relationship, whereas the treatment effects regarding OHRQoL, lip closure, and trauma incidences were found to be modest.
• With costs and treatment effects being equivalent, an early treatment approach can be advocated to enhance trauma prevention.

Objectives

To compare Oral health-related quality of life (OHRQoL) among 9-year-old children with excessive overjet (EO) to children with unilateral posterior crossbite (UPC) and children with normal occlusion (NO).

Materials and methods

The study sample sourced from 19 Public Dental Service Clinics in Sweden. Reported are baseline data originating from two controlled trials, one regarding UPC and the other focusing on EO. The NO children derive from the same trials. The UPC group comprised 93 children (45 boys and 48 girls), the EO group 71 children (36 boys and 35 girls), and the NO group 65 children (32 boys and 33 girls). In conjunction to a clinical examination, all children completed the Child Perceptions Questionnaire (CPQ_8-10) for evaluation of OHRQoL. The CPQ_8-10 comprises 25 questions grouped into four domains: oral symptoms, functional limitations, emotional, and social well-being. Validated questions about pain in the jaws and face were also included.

Results

The total mean CPQ score was 5.1 for the UPC, 7.4 for the EO, and 4.4 for the NO group, showing a significant difference between the UPC and EO (P = 0.048) and between EO and NO group (P = 0.012). These differences remained when adjusted for the confounders’ caries, trauma, enamel defects, and headache. No difference between UPC and NO was found. The EO children also reported significantly higher scores in the domains emotional and social well-being (P = 0.039 and P = 0.012).

Limitations

The study would be strengthened if a longitudinal design had been performed.

Conclusion

Children with EO reported significantly lower OHRQoL compared to children with UPC or NO. The children generally reported low CPQ scores that imply an overall fairly good OHRQoL.