Is early class III protraction facemask treatment effective? A multicentre, randomized, controlled trial: 3-year follow-up

Abstract

Objective: To investigate the effectiveness of early class III protraction facemask treatment in children under 10 years of age at 3-year follow-up.

Design: Multicentre randomized controlled trial.

Subjects and Methods: Seventy-three patients were randomly allocated, stratified for gender, into early class III protraction facemask group (PFG) (n = 35) and a control/no treatment group (CG) (n = 38).

Outcomes: Dentofacial changes were assessed from lateral cephalograms and occlusal changes using the peer assessment rating (PAR). Self-esteem was assessed using the Piers–Harris children’s self-concept scale, and the psychosocial impact of malocclusion with oral aesthetic subjective impact score (OASIS) questionnaire. Temporomandibular joint (TMJ) signs and symptoms were also recorded. The time points for data collection were at registration (DC1), 15 months later (DC2) and 3 years post-registration (DC3).

Results: The following mean skeletal and occlusal changes occurred from the class III starting point to DC3 (3-year follow-up): SNA, PFG moved forwards +2·3° (CG forward +1·6°; P = 0·14); SNB, PFG moved forwards +0·8° (CG forward +1·5°, P = 0·26); ANB, PFG class III base improved +1·5° (CG stayed about the same at +0·1°; P = 0·001). This contributed to an overall difference in ANB between PFG and CG of +1·4° in favour of early protraction facemask treatment. The overjet was still improved by +3·6 mm in the PFG and changed a small amount +1·1 mm in the CG (P = 0·001). A 21% improvement in PAR was shown in the PFG and the CG worsened by 8·4% (P = 0·02). There was no increase in self-esteem (Piers–Harris score) for PFG compared with the CG (P = 0·56) and no statistically significant difference in the impact of malocclusion (OASIS) between groups in terms of the changes from DC1 to DC3 (P = 0·18). TMJ signs and symptoms were very low at DC1 and DC3.

Conclusions: The favourable effect of early class III protraction facemask treatment undertaken in patients under 10 years of age, is maintained at 3-year follow-up in terms of ANB, overjet and % PAR improvement. The direct protraction treatment effect at SNA is still favourable although not statistically significantly better than the CG. Seventy per cent of patients in PFG had maintained a positive overjet which we have defined as ongoing treatment success. Early protraction facemask treatment does not seem to influence self-esteem or reduce the patient’s personal impact of their malocclusion at 3-year follow-up.

Keywords:

• Class III skeletal pattern
• early orthopaedic treatment
• protraction facemask
• randomized controlled trial

Acknowledgments

The 3-year follow-up study was sponsored by TP Orthodontics.

Thanks to: Cathy McDade, Consultant Orthodontist, Tameside General Hospital for helping to identify patients for inclusion; and Robin Gray who trained all clinicians to carry out the standardized TMJ clinical examination.