Class II div 1 Early intervention :Timing of referral for Class II division 1 children is extremely important as late referral may limit the treatment options available, particularly attempts at growth modification. On the other hand, recent evidence strongly suggests that there are few advantages to early treatment (undertaken as a first stage of treatment in the early mixed dentition) for Class II division 1 malocclusion and that starting treatment too early may actually reduce success and long-term outcome. It is therefore now recommended that a single phase of treatment is undertaken once the patient is in the late mixed dentition or early permanent dentition. This is the ideal time for orthodontic referral for the majority of Class II growing patients. The exceptions to this are if there is a significant risk of incisal trauma due to greatly increased<unk> , or if the child is being teased or bullied at school. For these patients, early treatment may be indicated and an earlier referral should be made for an orthodontic opinion. :Any habits must be completely stopped before treatment can be undertaken otherwise treatment is likely to be unsuccessful or relapse after completion. :Early treatment is defined as treatment provided in the early mixed dentition, usually between the ages of 7−9 years. This has also been called two-phase treatment, whereby a second separate definitive phase of treatment is undertaken when the patient reaches the permanent dentition. Late treatment, or one-phase treatment, is a single course of comprehensive treatment undertaken in the permanent dentition around the age of 12−14 years. Early treatment has been advocated to reduce the risk of incisal trauma, improve psychosocial well-being and reduce bullying. :It is also been claimed that early treatment can lead to superior outcomes in terms of efficiency, making definitive treatment easier, and efficacy, in that the final result is superior. :Further assertions have been made for early treatment in terms of improved skeletal pattern, and reduced need for extractions and orthognathic surgery; however, these have been disproved in recent high quality clinical trials. One high-quality randomized controlled trial compared early and late treatment of Class II division 1 malocclusion with functional appliances. Although differences were found between treated patients and untreated controls after the initial phase, following a second phase of treatment there was no lasting difference in terms of skeletal pattern, extraction pattern or self-esteem. Detrimental effects were seen in those who had undergone early treatment; more appointments, longer total treatment time and associated costs, and a worse final occlusal outcome as indicated by the Peer Assessment Rating (PAR). Functional appliances :Functional appliances are a range of fixed and removable appliances that cause their effect by influencing the muscle groups that control position and function of the mandible, transmitting forces to the dentition and basal bone. The result is a decrease in<unk>  and correction of the buccal segment relationship, caused by both skeletal and dental changes. A recent study quantified the changes seen after a first stage of functional treatment. Skeletal change was attributed to restraint of maxillary forward and downward growth and increased growth and forwarding positioning of the mandible, contributing to 27% of the<unk>  reduction and 41% of buccal segment correction. Dental changes included retroclination of maxillary incisors, proclination of mandibular incisors and mesial eruption of mandibular molars. The majority of<unk>  reduction and buccal segment correction is dental, 73% and 59%, respectively. :Soft tissue changes include elimination of lip trap and improved lip competence. It has also been postulated that tongue activity and soft tissue pressures from the lips and cheeks might be altered, enhancing the soft tissue environment. Twin block appliances The Twin Block appliance has been used in most studies evaluating functional appliance treatment as it is considered to be the 'gold standard' against which other appliances should be tested. When compared to other functional appliances, the Twin Block appliance was found to produce a statistically significant reduction in skeletal base discrepancy (ANB = -0.68 degrees; 95% CI -1.32 to -0.04) when compared to other functional appliances, although there was no significant effect from the type of appliance on the final<unk> . The Twin Block has also been shown to cause clinically significant beneficial changes to the soft tissues. There are problems associated with the Twin Block including excessive lower incisor proclination, a significant failure-to-complete rate of 25%, and a breakage rate of up to 35%. Lower incisor proclination occurs with most functional appliances and this must be considered during treatment planning and monitored throughout treatment. Twin Block appliances can also cause an increase in vertical dimension, which may be desirable in some cases but may not be beneficial in patients with an increased lower anterior face height. In these patients, careful control of the vertical dimension should be planned. Herbst appliance The success rate of the Herbst appliance, often considered to be a 'compliance-free' appliance, was found to be much higher than the Twin Block in one study, with a failure-to-complete rate of 12.9%. This is approximately half that of the Twin Block so may be considered in patients where compliance is predicted to be difficult. However, the Herbst is considerably more expensive and demonstrated a higher breakage rate so that the benefits of reduced compliance requirements must be balanced against this. Headgear Headgear exerts force to the dentition and basal bones via extra-oral traction attached directly to bands on the teeth or to a maxillary splint or functional appliance. The effects are mainly dento-alveolar with some skeletal effect through restriction of maxillary downward and forward growth. Several studies found an additional small effect on mandibular growth when headgear is used in conjunction with an anterior bite plane. The effect of headgear treatment, as early treatment, was compared to one-phase treatment, carried out later, in a study of two trials. Both found a significant reduction in<unk>  and improvement in skeletal relationship after headgear treatment. There was no difference in any outcomes that could be attributed to treatment timing, with the exception of risk of trauma where the later treatment group showed twice the risk of incisal trauma. The Cochrane review summarizes that 'no significant differences, with respect to final<unk> , ANB, or ANB change, were found between the effects of early treatment with headgear and the functional appliances'. However, headgear is highly reliant on good patient compliance, with 12−14 hours a day of wearing required to achieve the effects described. Fixed appliances Fixed appliances can be used alone or in combination with extractions or temporary anchorage devices to retract the maxillary teeth to correct a Class II division 1 malocclusion by dental means only. Class II intermaxillary elastics are used to retract the maxillary teeth against the mandibular teeth, with reciprocal mesialization and proclination of the mandibular teeth. Late intervention Cochrane review showed that, at the end of all treatment, no significant differences were found in<unk> , skeletal relationship or PAR score between the children who had a course of early treatment, with either headgear or functional appliances, and those who had not received early treatment. The only outcome to be affected by treatment timing was the incidence of new incisal trauma, which was significantly reduced by early treatment with either functional appliance or headgear (odds ratio 0.59 and 0.47, respectively). The Cochrane review concludes 'the evidence suggests that providing early orthodontic treatment for children with prominent upper front teeth is more effective in reducing the incidence of incisal trauma than providing one course in early adolescence. There appears to be no other advantage for providing early treatment'.
Overjet
Isochronic tones
Skull bossing
Triangular face
Stunt 
Dichotic pitch
Calcaneal pitch
Oak wilt