Puneet Batra

Malocclusion is the departure from normal relationship between teeth in the same and opposite arch. Different authors have described class III in different terms. Heterogeneity of phenotype and variation in clinical severity diversify class III malocclusion. Globally the prevalence is within 0%-26.7% in different populations. Prevalence in Asians is higher for Angles class III malocclusion. Interaction of innate or genetic and environmental leads to class III malocclusion. Treating a malocclusion of class III nature is a complex problem because the patient's pattern of growth is unpredictable and unfavourable. Decision should be made either to treat or wait till the growth is over in cases of developing class III condition. If the patient is non-growing then the severity of Class III is assessed and accordingly treatment plan is devised.

Class II malocclusion is among the most usual orthodontic disparity experienced, and it is likely to produce significant negative aesthetic and social effects on children's lives, predispose them to dental trauma or affect their dental health. The widespread presence of Class II division 1 and Class II division 2 in India is 7% and 1.9% respectively, with over 50% of all Class II having a subdivision component. Class II is a compound clinical entity that requires a blend of distinct 3-dimensional skeletal and dental components. Class II malocclusion's are of particular attention to the orthodontists, as they account for a big proportion of patients they attend.

The maxillary growth impairment, which is often presented by patients with cleft lip and palate (CLP), can result in serious skeletal and/or dental pathological conditions in all 3 planes of space (vertical, horizontal, and transverse). Anteroposterior maxillary retrusion associated with a relative class III malocclusion as well as unilateral or bilateral palatal collapse of the lesser segment of the maxilla producing a narrowing of the dental arch is probably the most recurrent and challenging problem to deal with. This book deals with all aspects of a developing Class III malocclusion in patients with repaired cleft lip and palate.

Obstructive sleep Apnoea (OSA) was first described in medical literature in 1965. Obstructive sleep apnoea syndrome (OSAS) is characterized by recurrent episodes of partial or complete upper airway obstruction during sleep. This manifests as a reduction (hypopnoea) or complete cessation (apnoea) of airflow despite ongoing inspiratory efforts resulting in oxygen desaturation and arousals. Daytime symptoms such as excessive sleepiness are thought to be related to sleep disruption (repetitive arousals) and possibly to recurrent hypoxemia. It is a relatively common condition occurring in 2 to 4 % of males and 1 to 2 % of females in middle age. There are many causes of OSA like obesity, age, enlarged tonsils, narrower natural throat form, smoking and alcohol use etc.