GAP Australasian Dentist Sept Oct 2020

Category 34 Australasian Dentist What is a class 2 malocclusion? The Class 2 malocclusion is considered the most frequent problem presenting in an orthodontic practice In Australia. It may reflect a Maxillae–Mandible skeletal disharmony with underdevelopment of mandibular growth and/or maxillary ex- cess, leading to a convex soft tissue profile. As we all know in a Class 1 molar relationship the Mesiobuccal cusp of the upper first permanent molar occludes with the buccal groove of the lower first molar. In the Class 2 malocclusion. (Figure 1) The Mesiobuccal cusp of the Upper first permanent molar occludes mesial to the ideal Class 1 position. (Figure 2) Class 2 malocclusion is mainly classified into Class II Div. 1, and Class II Div. 2 In aClass 11Division1malocclusion a Class II molar relationship is present with usually proclined upper central incisors. There is usually an increase in overjet with normally protrusive incisors (Figure 3) . In the Class 11 Division 2 there is a Class II molar relationship. present with retroclined upper central incisors, upper lateral incisors may be proclined or normally inclined. The Overjet is usually this problem. In future articles I will be discussing the management of the Class 2 patient who presents in the late mixed dentition, in the permanent dentition and are still growing, and then finally the non- growing patient. In the primary dentition and early mixed dentition, the upper deciduous second molars (and ultimately the first permanent molars) can be related to their mandibular counterparts either in a flush terminal plane (50% Class 2) ,mesial step (Class 1) or distal step (full Class 2) relationship (Figure 5) Management of the Orthodontic Class 2 Patient (Part 1) clinical By Dr Geoffrey Hall, Specialist Orthodontist, B.D.Sc (Melb) Cert.Orth( Uni Of Penn) MRACDS (ORTH) Director OrthoED Institute Figure 1 Ideal Class 1 Figure 4 Class 2 Div 2 Figure 3 Class 2 Div 1 Figure 2 Class 2 Buccal relationship minimal (Figure 4) u Different age groups presenting to a practitioner with a Class II malocclusion u Primary dentition u Early mixed dentition u Late mixed dentition u Permanent dentition who are still growing u Non growing patients Management of those age groups can be also classified as children, adolescent, adults and different approaches are required for these different groups, based on age, amount of skeletal growth remaining, the aetiology of the problem, the patients facial profile, the degree of skeletal discrepancy, the amount of dental crowding, the anterior overbite and skeletal vertical and patient potential cooperation. This list is by no means exhaustive but demonstrates the fact a thorough diagnosis, problem list and risk management assessment is essential for each individual patient to formulate the best treatment plan for their individual situation . In this first article I will discuss growth and development and how this can affect development of a Class 2 malocclusion and the possible management of the young child (age 6 to 10) who may present with Figure 5 Terminal plane relationship We have understood in the past that a flush terminal plane was a normal relationship in the primary dentition and early mixed dentition – and the lower permanent molars generally moves forwards further than the upper molars, due to the extra leeway space present in the mandibular arch compared to the maxillary arch – hence allowing the patient to obtain the ideal class I molar relationship. This change in arch length occurs during the mixed dentition as a patient loses their deciduous teeth and is replaced by the underlying permanent teeth. Having said all that, early loss of primary teeth (especially in the upper arch) with no space maintenance can result in a Class 2 dental malocclusion. However, there are many factors that are present, and the leeway space that Nance originally coined, is an average amount and does not relate exactly to each individual patient. Also, the amount of Geoffrey Hall