ALLERGIES, HABITS AND MALOCCLUSION IN YOUNG CHILDREN - WHAT HAPPENS OVER TIME?

Some clinicians advocate very early treatment in the primary (~ages 3-5) dentition and recommend interventions claiming they will prevent future orthodontic problems. But what if we did nothing and observed them? This very interesting article from Sweden followed 277 children from age 3 to age 11.5 and evaluated the presence of malocclusion, sucking habits, breathing problems, allergies and trauma over time.

There was quite a high prevalence of malocclusion at age 3 of 71% and although this improved by age 7 to 56%, it worsened again to 71% by age 11.5. However ~45% of subjects were considered in severe or moderate 'need' of treatment so ~55% had minor or no need. Many advocates of early treatment suggest intervention for open bites but interestingly this was one of the malocclusions that tended to self-correct as found by previous authors. Conversely deep bites did tend to worsen. As with previous studies trauma to the top front teeth was ~2.2 times more likely with increased protrusion/overjet.

Another re-emerging (previously in 1930's then 1960-70's) claim in orthodontics is the influence of habits and allergies on malocclusion and that early intervention is required to prevent adverse growth effects. This long-term observational study found sucking habits had little or no association with anterior open bite or posterior crossbite in the permanent dentition. As I have discussed in a previous Blog, many children stop the habits themselves as they get older and an open bite can improve spontaneously so treatment may not be indicated except in those that persist longer term.

Similarly allergies at age 3 had NO association with any future malocclusion at age 11.5. There are many good reasons for allergy, tonsil and adenoid treatments but to prevent abnormal facial growth is not one of them. I have personally had an ENT tell my wife that our 9 y.o. daughter (who suffers from allergies) required a turbinectomy otherwise she will undergo abnormal jaw growth - you can probably guess my response to that! My daughter has normal horizontal and vertical facial growth with mild crowding and although she will require some orthodontic treatment once all adult teeth have erupted for the mild crowding, her growth is proceeding just fine without the surgery. I feel sorry for those parents that do not have the knowledge of normal facial growth that I do as they may be 'scared' into having procedures for their children that they may otherwise think twice about. This article helps contribute to that knowledge so thanks to this Swedish team for following this group and presenting their findings.

Dr Peter Miles is the orthodontist at Newwave Orthodontics in Caloundra, Australia and teaches orthodontics part-time at the University of Queensland and is a visiting lecturer at Seton Hill University in the USA. Peter is one of the editors and authors of the orthodontic textbook, 'Evidence-Based Clinical Orthodontics'. Importantly, he has no financial interest in any products mentioned in these Blogs.

HIGHEST VIEWED BLOGS SO FAR!!

For this Blog I thought I would recap the 5 most popular Blogs I have published so far and it is interesting to note that they are all related to early #orthodontic treatment. Although some of these involve the same topic I will rank them in order of the most viewed individual Blogs. Note the text in a different colour is a link to the original Blog or document so just click on it if you wish to know more.

1) The most read and searched Blog and also one of the more recent was 'Maxillary Expansion - Unexpected Benefits?' in September this year. This Blog has interest for readers who are clinicians as well as the general public discussing #expansion and its possible effect upon bed-wetting, sleep #apnea and middle ear problems. Expansion is a common procedure in orthodontics but there is limited quality research on these specific areas. It is also an emerging topic with a lot of mis-information accessible on search-engines and deserves more well-designed research in the future.

2) On a similarly related topic was this Blog back in January 2015 titled 'Do Orthodontic Extractions Cause Sleep Apnea?'. Again it is a controversial and emerging subject with a lot of mis-information which is easy to disseminate when there is minimal research. I am glad these two topics have received such an enthusiastic response.

3 - 5) The next three topics all related to #Myofunctional appliances. In order these Blogs were 'More on Myofunctionals - 2 Clinical Trials' followed by the first of the Blogs on this topic, 'Myofunctional Appliances - What's the Evidence?'. The third and most recent of the Blogs on this topic was also the most recent Blog prior to this and reported the 'Results of a RCT of a Prefabricated Functional Appliance'. This is an area dominated on search engines by companies and clinicians extolling the virtues of these appliances and treatment approach. The higher levels of evidence come from clinical trials which are discussed in these Blogs and although these trials are not ideal they currently are the best level of evidence we have and come to a similar conclusion. Although they find statistical differences, these differences were quite small and indicated that these appliances were less effective than more conventional treatments for bite correction. Despite being in an evidence-based era where we would like to see well-conducted clinical trials upon which to base our treatments, there is limited quality research and both clinicians and the general public need to be wary of the claims being made until well designed research is available.

I would like to thank you the reader for your interest as my goal throughout is to provide quality information for clinicians and the general public on the more controversial topics in orthodontics. I would also like to point out that I have no financial interest in any appliance or technique I discuss in these Blogs so when gathering information, consider whether the source of information is potentially biased and associated with that particular appliance or technique.

Remember any of the Blogs can be found at http://newwaveorthodontics.blogspot.com.au/ and scrolling down and older ones can be accessed at the bottom of the page by clicking 'older posts'. Wishing all a happy, safe & prosperous 2016.

Dr Peter Miles is the orthodontist at Newwave Orthodontics in Caloundra, Australia and teaches orthodontics part-time at the University of Queensland and is a visiting lecturer at Seton Hill University in the USA. Peter is one of the editors and authors of the orthodontic textbook, 'Evidence-Based Clinical Orthodontics'.

MAXILLARY EXPANSION - UNEXPECTED BENEFITS?

Maxillary expansion is a relatively common procedure in orthodontic treatment for bite correction and I have Blogged previously about it for the correction of crossbite as well as its use in creating space. However, expansion has also been showing some unexpected benefits for some patients in other areas which I will discuss in this Blog.

Expansion of the upper jaw is most effective in pre-pubertal children when the midline suture is still responsive and the surrounding bones are more malleable. As the maxilla (upper jaw) forms the floor of the nasal airway and supports the soft tissues of the nose, this expansion has been suggested to improve a constricted or congested airway. Much of this was anecdotal as improvements can occur coincidentally or with time and not necessarily be related to the procedure. This is why research in the form of clinical trials is important to try to reduce the biases inherent in simply observing something. However there is a growing body of evidence of the potential beneficial effects of maxillary expansion beyond the correction of dental crossbites.

Expansion and Nocturnal Enuresis/Bed-wetting:
In the 1990's some research suggested that expansion of the upper jaw may help reduce nocturnal enuresis or bed-wetting in children. More recent studies agreed with these findings showing significant reductions (~75%) in the number of nights of bed-wetting following expansion with ~30% were completely dry at night after expansion. This was even in the absence of a pre-existing crossbite. Suggested reasons for this improvement relate to an indirect effect on the pituitary gland or an improvement in the airway with expansion which may help with a possible association between enuresis and sleep disordered breathing in children.

Expansion, Congestion, Sleep Apnoea:
One of the above papers also found that nasal airflow increased while nasal resistance to airflow decreased. Earlier research by Peter Vig in the 1980's found that rapid maxillary expansion resulted in a significant reduction in nasal resistance but there was considerable variation and so the outcome was not predictable. Other research has shown this reduction remained a year later. Another paper found those with the highest initial nasal resistance tended to obtain the greatest benefit from expansion with the greatest reduction in nasal resistance.

Maxillary expansion has also been suggested to improve obstructive sleep apnoea or apnea in children (where the child stops breathing several times per hour of sleep). I have discussed extractions and sleep apnoea previously. Studies have found expansion can result in a significant reduction in the numbers of episodes of apnea in children including those with enlarged tonsils and adenoids. Although the response is unpredictable the results are promising enough to warrant more comprehensive clinical trials and to be considered as a treatment strategy especially when there are other reasons to consider maxillary expansion.

Expansion and the Middle Ear:
In studies on patients with narrow arches and conductive hearing loss it has been found that rapid and semi-rapid expansion of the maxilla resulted in an improvement in hearing and eustachian tube function and these improvements held up for 3/4 of the subjects up to 2 years later. However these are children with narrow jaws so the same may or may not hold for those with normal or wide arches.


Summary
So it seems that maxillary expansion may have benefits beyond correcting crossbites and creating some space. However it must be kept in mind these studies are not definitive and the outcomes are not guaranteed so more research in the form of randomised clinical trials is indicated. For this reason expansion may be suggested when it is indicated for other reasons or in consultation between your medical practitioner/sleep physician/Otolaryngologist (ENT) and your orthodontist.


I would like to thank Dr James Noble (Orthodontist - Toronto) for his feedback on this Blog topic.

Dr Peter Miles is the orthodontist at Newwave Orthodontics in Caloundra, Australia and teaches orthodontics part-time at the University of Queensland and is a visiting lecturer at Seton Hill University in the USA. Peter is one of the editors and authors of the orthodontic textbook, 'Evidence-Based Clinical Orthodontics'.