Almost half of the population in the UK have a Class II malocclusion, with many going untreated in their youth or suffering some degree of relapse leaving them with a Class II bite as adults. For instances where the Class II is not their main concern, it is important to be able to advise the patient of the consequences of leaving it untreated.
The most important step in being able to advise your patient appropriately is to ensure you have the correct diagnosis. You will want to know whether the Class II is skeletal or solely dental, so that you can have an idea of the implications of leaving it be or how straightforward it may be to correct.
Many patients with a Class II skeletal relationship may posture their lower jaw forwards for photographs so make sure you’re not being fooled in your extra-oral examination! Make a note as to whether the Class II is due to the skeletal base (retrognathic mandible - look at the profile but also the molar relationships), soft tissues (lower lip trap - encouraging the upper incisors forward and pushing the lowers back), local factors (crowding resulting in the proclination of one upper incisor for instance), habits (thumb sucking - again encouraging the upper incisors forward and pushing the lowers back), or some combination of these.
The implications of leaving a Class II untreated are various. Foremost in the minds of many patients is likely to be the aesthetics - many are quite conscious of their front teeth feeling “pushed forwards” (Class II div 1). It is quite common for children with this bite to be teased about their appearance, and of course that can stay with people through to adulthood. Those with retroclined, or leaning back, upper incisors (Class II div 2 patients) may be less self-conscious of their upper front teeth, but this will quickly change if they have simple tooth alignment only - essentially converting these patients into a Class II div 1!
Class II malocclusions are often also associated with an increased overbite. This is important to look out for as, particularly in adults, it can traumatise the soft tissues of the anterior palate and the gingivae. This poses a risk to the upper incisors, and traumatic recession at the upper incisors can quickly progress to mobility of the upper incisors. A Class I bite is when the incisal edges of the lower incisors are resting on the cingulum plateau of the upper incisors. When this is not the case, there is an increased risk of dental trauma. Research has shown large overjets to put patients at greater risk of incisal trauma, particularly where the lower lip rests behind the edges of the upper incisors.
In a Class I bite, all of the teeth meet a hard tissue stop, and so there is less freedom of movement for relapse after your orthodontic treatment is complete. Cases that finish as Class II may well be more reliant on retainers to prevent relapse, and in some cases with remaining deep bites an upper bonded retainer may not be feasible due to occlusal interferences. Whilst we always encourage patients to wear removable retainers for life, some who are particularly prone to relapse (such as those who have had closure of a diastema) tend to benefit greatly from a bonded retainer which may not be possible if the Class II is not corrected.
With all of this in mind, there will be some patients who decide against Class II correction and simple alignment may well be a great option for them. However, for some others it will be an all-or-nothing, where simple alignment may actually cause more harm than good. This will have given you an idea of what to look out for, but don’t forget that if you’re not sure you can always elect to use our specialist support for your cases so that you’re leaving no stone unturned.