Very few indications justify early treatment for severe Class II malocclusions

Abstract

Design This was a single-centre two-phased, parallel, randomised clinical trial (RCT) conducted over a period of more than 10 years.Intervention Children were enrolled who had severe (=7 mm overjet) Class II malocclusions and who were developmentally at least a year before their peak pubertal growth. During the first phase of the trial, the children were randomly assigned to either treatment starting in the mixed dentition (either combination headgear or a modified bionator) or to observation only. Phase-1 treatment was carried out by an orthodontist according to a standardised protocol. Records for all children were made again after 15 months. A second phase of comprehensive fixed-appliance treatment was planned for all the children when they had early permanent dentition. The children were then randomised, within their phase-1 treatment group, to one of four orthodontists for completion of orthodontic treatment (see Figure 1).Outcome measure Primary outcomes were a restricted set of 11 cephalometric measures used to describe the position and relationship of the maxillary and mandibular skeletal and dental units. Secondary outcomes included the alignment and occlusion of the teeth [peer assessment rating (PAR) scores], the duration of treatment, and the proportion of children who required more complex treatment involving extractions or orthognathic surgery.Results Of the 166 children who completed the first phase of the trial, 137 completed phase-2 with one of the four finishing clinicians. After the second phase, early treatment had little effect on the subsequent treatment outcomes — measured as skeletal change, alignment and occlusion of the teeth, or length and complexity of treatment. The differences created between the treated children and untreated control group by phase-1 treatment before adolescence disappeared when both groups received comprehensive fixed-appliance treatment.Conclusions This RCT suggested that two-phase treatment started before adolescence in the mixed dentition might not be any more clinically effective than a single-phase treatment started during adolescence in the early permanent dentition. Early treatment also appears to be less efficient, in that it produced no reduction in the average time a child is in fixed appliances during a second stage of treatment, and it did not decrease the proportion of complex treatments involving extractions or orthognathic surgery.