Doctoral dissertation

Saara Markkanen: Children’s Sleep Disordered Breathing,Tonsil Hypertrophy and Dentofacial Development

Saara Markkanen
Paediatric sleep disordered breathing (SDB) is a common cause of a visit to an otolaryngologist. The mildest form of paediatric SDB is primary snoring (PS) and it is estimated that up to 15% of all children snore frequently. The prevalence of paediatric obstructive sleep apnoea (OSA), which is thought to be more severe form of SDB, is suggested to be 1% to 5%.

M.D., Specialist Saara Markkanen studied the phenomenon in her doctoral dissertation Children’s Sleep Disordered Breathing, Tonsil Hypertrophy and Dentofacial Development.

The pathophysiology of paediatric SDB is not fully understood, although tonsil hypertrophy is considered to be the primary pathophysiological factor. There is a distinct difference between paediatric and adult SDB, where overweight is a frequent but not the only cause. Furthermore, the symptoms and clinical features of SDB change along with growth.

Paediatric SDB cannot be considered to be a stabile entity throughout childhood and adolescence. Therefore, it is important to obtain knowledge of the different features of children with SDB at different ages. Knowledge of these features enables early recognition and treatment and might prevent the long-term effects caused by poor sleep quality and increased night-time sympathicotonia. The consequences of SDB, such as behavioural and cognitive problems, poorer school performance, dentofacial morphology changes, growth impairment and cardiovascular effects, are widely recognised and studied.

The present study concentrates on SDB and OSA in two to three years old patients. Furthermore, a review and a meta-analysis of the contemporary literature on the influence of tonsillectomy and/or adenoidectomy (hereafter, tonsil surgery) on dentofacial development in children is included. These subjects integrate because tonsil surgery is a primary treatment method for paediatric OSA and paediatric OSA and SDB are connected to changes in dentofacial morphology.

In the present study, minor dentofacial morphology changes were already found in two to three years old children suffering from SDB. This is a significant finding because SDB has previously been associated with a variety of dentofacial morphology changes, and it could therefore be shown that these changes start to emerge at a young age. There is scarcity of previous studies which concentrate on patients this young, and therefore the results of the present study are notable. Furthermore, it was observed that total snoring time in polysomnography (PSG) was longer in children with OSA than in children with PS. The total snoring time is not a well-researched parameter in paediatric SDB, and this finding can offer new opportunities when diagnosing paediatric OSA. In addition, it was observed that children with OSA were more likely to breathe through their mouth and have a larger adenoid size in contrast with children with PS. However, no difference in palatine tonsil size was found in this age group of two to three years old children.

A review and a meta-analysis of the contemporary literature of the influence of tonsil surgery on dentofacial development was conducted. The risk of bias in the review had to be considered high because the number of studies which fulfilled the inclusion criteria was low, the studies were methodically heterogenic, and the quality of the studies was moderate at best when estimating the risk of bias in individual studies. However, modest evidence that tonsil surgery has a positive effect on dentofacial development in children was found. The main finding in the review was that the growth direction of the mandible changed from vertical to more horizontal.

The findings of the studies in this dissertation add to the body of knowledge on paediatric SDB and OSA and their clinical and PSG features. Furthermore, they combine contemporary knowledge on SDB, mouth breathing, hypertrophied tonsils and dentofacial morphology. The evident strength of the studies is the young, two to three years old participants. There is a scarcity of knowledge of the consequences of SDB in this age group because most of the literature concentrates on older children or the age distribution in the studies is heterogeneous.

Based on the results of this dissertation, it can be concluded that SDB symptoms in two to three years old children should be noticed and treatment opportunities considered because the first signs of long-term influences, such as changes in dentofacial morphology, could already be seen in this young age group. More research is needed to determine whether total snoring time could be a useful method in OSA diagnostics and whether adenoidectomy alone could be a sufficient treatment method for young patients.

The doctoral disseertation of M.D., Specialist Saara Markkanen in the field of Otorhinolaryngology titled  Children’s Sleep Disordered Breathing, Tonsil Hypertrophy and Dentofacial Development will be publicly examined in the Faculty of Medicine and Health Technology at Tampere University on Friday 30 October 2020 starting at 12 o'clock in Arvo building auditorium F114, Arvo Ylpön katu 34. The Opponent will be Professor Heikki Löppönen from University of Eastern Finland. The Custos will be Professor Markus Rautiainen.

Because of the coronavirus situation, only a limited amount of persons will be allowed to participate in the event. Please register at saara.markkanen [at] The defence can also be followed via remote connection.

The dissertation is available online at

Photo: Mimi & Nöde Photography