Bruxism is a parafunctional activity caused by excessive grinding or clenching of the teeth against each other.
It is an involuntary behaviour unrelated to the normal activity of eating or talking and most often occurs during sleep, although some people may also do it during the day.
Some people have chronic long term bruxing habits whereas others experience intermittent periods of acute bruxing activity. We are all living increasingly busy and stressful lives so unsurprisingly parafunctional bruxing habits have become a relatively common phenomena.
As dentists we regularly see the significant long term side effects this subconscious behaviour can have on the health of the teeth and jaws. Persistent bruxing substantially increases the amount of wear on the teeth and also reduces the lifespan of fillings, crowns or any other restorations within the mouth. People who are bruxing are more at risk of damaging their teeth and restorations. If there is a history of worn down teeth, repeatedly breaking fillings or chipping and cracking teeth, bruxing behaviour is likely to be the underlying cause. Once a filling breaks or starts to wear down significantly, it may allow bacteria to get trapped and cause decay to develop. Even in an unrestored tooth, once the natural outer protective enamel layer has worn through from persistent grinding, the more porous sensitive dentine layer is exposed which increases the risk of tooth sensitivity and decay. Problems related to cracked teeth from severe bruxing can have even more serious consequences, including severe tooth pain needing root canal treatment, or even a tooth completely fracturing apart, whereby the tooth cannot be saved and needs to be extracted.
The aesthetic appearance of the teeth may also be compromised due to bruxing. When the natural rounded contours of the teeth are lost from heavy grinding, the front teeth can appear flat which tends to age a person’s smile. Where there is already significant wear of the teeth, sometimes it is possible to rebuild and restore the worn away part of the teeth with tooth coloured composite filling material or laboratory made porcelain restorations bonded to the teeth. The aim of this is to conservatively protect the teeth from further wear, restore proper tooth function, reduce sensitivity and restore optimum aesthetics.
Chronic bruxing is also associated with jaw problems. Parafunctional bruxing forces can overload the jaw muscles and temporomandibular joint (TMJ) which controls jaw movement. This increased tension in the jaw may lead to a range of symptoms including: stiffness and aching in the jaw muscles, pain on jaw opening, reduced jaw opening, jaw clicking, headaches and premature wear of the TMJ.
There is no definitive cure for bruxing and people who suffer from bruxing are often completely unaware they are doing it during sleep. Dentists are best able to recognise the signs and symptoms of bruxing behavior and to treat it appropriately. Identifying when a bruxing habit exists in a patient is very important. In practical terms this means for any restorations being planned, the design of them needs to have a particular emphasis on long term strength and durability. Where there are visible cracks starting to occur in the teeth, bruxing habits may exacerbate the problem, so it is often wise to intervene early and electively place a protective restoration such as a crown or onlay to reinforce the tooth before the crack worsens or symptoms develop. Protective mouth guard splints worn at night may also be prescribed to help control bruxing habits. They are a simple and effective way of reducing the detrimental effects on the teeth and jaw from persistent grinding and clenching. There are various different types of bite splints. A dentist will decide the most suitable design for each patient depending on whether tooth wear or jaw pain issues are the predominant concern.
The long term management of bruxism can sometimes be difficult but with the proper planning we can help minimize its effect on the teeth and jaws. Early identification and close monitoring of tooth wear is important and a conservative proactive and preventative approach is best.
Brad Ngan BDS (Otago)