Whiplash in Dentistry...

If one is looking for a medico-legal ‘hot potato’, it doesn’t come much hotter at present than ‘whiplash’. In fact, that particular potato is sufficiently hot to cause burning of fingers and frothing at the mouth. Depending on your perspective it is either a common and oft-times serious consequence of motor vehicle accidents (MVAs), or a grossly exaggerated pseudo-medical condition. Either way, you will have had to have been in Outer Mongolia for the past several months not to have been aware that there has been, and continues to be, significant changes with regard to the medico legal reporting of whiplash claims.

The Transport Select Committee started the process by investigating the cost of motor insurance in whiplash claims. The original aims of their suggested reforms aimed at the reduction of the number of fraudulent / exaggerated whiplash claims and implementing punishment of fraudulent claimants. Northing wrong there; however, the outcome of this consultation was to implement the notion of fixed costs medical reports, initially from general practitioners, and this has been seen by medical expert witnesses as a restriction on their ability to trade.

This article will consider the following questions:

• What is “whiplash injury”?

• Does it cause temporo-mandibular dysfunction?

• What is the cost of whiplash to motor insurance claims?

What is ‘whiplash injury’?

Whiplash is a relatively common injury that occurs to a person's neck and/or head following a sudden acceleration-deceleration force, most commonly from motor vehicle accidents. The term ‘whiplash injury’ describes damage to both the bone structures and soft tissues, while ‘whiplash-associated disorders’ describes a more severe and chronic condition. Fortunately, whiplash is typically not a life-threatening injury, but it can lead to a prolonged period of partial disability

The Mechanism of Whiplash

Whiplash is most commonly caused by a motor vehicle accident when the car in which the person is travelling is not moving, and is struck by a vehicle from behind without notice. It is commonly thought the rear impact causes the head and neck to be forced into hyperextension as the seat pushes the person's torso forward, and the unrestrained head and neck fall backwards.

After a short delay the head and neck then recover and are thrown into a hyperflexed position. More recent studies and investigations using high-speed cameras and sophisticated crash dummies have determined that after the rear impact the lower cervical vertebrae (lower bones in the neck) are forced into a position of hyperextension while the upper cervical vertebrae (upper bones in the neck) are in a hyperflexed position. This leads to an abnormal S-shape in the cervical spine after the rear impact that is different from the normal motion. It is thought that this abnormal motion causes damage to the soft tissues that hold the cervical vertebrae together (ligaments, facet capsules, muscles). Whiplash is often more serious when the sudden movement is not directly forwards or backward, or where the neck is not straight when the impact is sustained, since the neck is less capable of dealing with extremes of movement under these circumstances. Side impacts, or those involving sudden rotation of the head and neck often result in more serious cases.

Whiplash is also generally more severe when the impact is unexpected – as one is not able to brace oneself for the impact and thereby lessen any potential movement of the head in relation to the rest of the body. Impact sustained from behind while looking to one side can result in more complex and painful whiplash injury. In the case of road traffic accidents, a significant size and weight difference between the vehicles involved is also a factor. Where a small vehicle is struck from the rear by a larger vehicle, it will accelerate more rapidly and therefore there is an increased risk of a more serious injury.

The Temporo-mandibular Joint [TMJ] 

The TMJ comprises the condyle (head) of the mandible separated from the articular portion of the temporal bone by a disc. The most common damaged suffered by one or both TMJs may be fracture of the thin neck of the condyle (often undiagnosed), or internal displacement of the disc. Either can upset the delicate balance of the mandible Internal derangement of the TMJ is defined as a disruption within the internal aspects of the TMJ in which there is a displacement of the disc from its normal functional relationship with the mandibular condyle and the articular portion of the temporal bone. It is usually treated with nonsurgical methods initially, but should these methods prove unsuccessful they are often followed by surgical methods.

Temporo-mandibular dysfunction [TMD]

Temporo-mandibular dysfunction [TMD] is a nonspecific term representing a variety of painful and/or dysfunctional conditions involving the masticatory muscles and the temporo-mandibular joints (TMJs). The three cardinal symptoms of TMJ disorders are facial pain, restricted jaw function and joint noise. The Quebec Task Force on Whiplash-Associated Disorders noted that temporo-mandibular dysfunction (TMD) may be manifested with any grade of whiplash severity. At the turn of the century, TMD was thought to account for loss in productivity of thirty billion dollars and 550 million working days a year in the USA. TMD sometimes presents in individuals involved in MVAs. While most people involved in minor motor vehicle accidents recover quickly without any chronic symptoms, some continue to experience symptoms for years after the injury that require medical care, disability, sick leave and lost productivity.

Diagnosis

To determine TMJ dysfunction, one needs to carry out a detailed physical investigation and one or more of X-ray, CT scan, MRI scan and/or arthrography. No radiological (X-ray) investigation should be requested unless it can be clinically justified. A magnetic resonance image (MRI) scan is a non-invasive procedure using magnetic and radio waves, meaning that there is no exposure to X-rays or any other forms of damaging radiation. MRI shows the soft tissues of the body in great detail and is superior to computerised anatomical tomography (CAT) scans and other forms of X-radiation. CAT scans are useful for evaluation of bony deformities. Arthroscopy is often employed as well. Arthroscopic surgery appears to be a safe minimally invasive and effective method for treating internal derangements of the TMJ, and usually fills the void between failed non-surgical treatment and open surgery. It is associated with fewer complications and a shorter hospital stay

Treatment

The present standard of therapy for common nonstructural TMD is conservative, noninvasive, reversible pain management with multidisciplinary cognitive and behavioral therapy, masticatory muscle relaxation, and jaw habit (clenching/ bruxing) modification measures. While many dentists ands specialist prosthodontists believe that dental orthotics (splint, bite plate, and so on) have efficacy beyond placebo effect, others dispute this and say they are commonly used because patients want or perceive a benefit. At the least, such devices should not cause changes in tooth positioning but should aim to decompress the joint.

After establishing a diagnosis, physicians can provide accurate information emphasizing patient understanding of a non-dental pain disorder. Counseling to alter patterns of negative thoughts and dysfunctional attitudes and foster healthy adaptive thoughts, emotions, and actions is indicated. Appropriate patient self-management includes warm compresses, soft diet, and cessation of gum-chewing. Irreversible treatments like orthodontics, bite adjustments, tooth restorations, and surgery are usually inappropriate for TMD. There may then also not be a basis for the use of any painful therapies; jaw manipulation and chiropractic jaw treatments may prolong, propagate, and complicate the disorder.

Legal ‘jawlash’ Distinctions: Medical & legal

MVA-TMD causation controversies are primarily legal, and legal causation does not correlate with medical causation.

Legal causation relates to the requirement to establish a probable cause - a relationship between the patient’s TMD and the motor vehicle collision at a standard of ‘more likely than not’, which would be unacceptable by medical standards. TMD may be caused, from a legal perspective, by a motor vehicle collision, but has not been proven to be medically caused by a motor vehicle collision. The medical aetiology of most TMD is incompletely understood, and there are two very opposing perspectives regarding TMD that is allegedly whiplash- related. The first school of thought is that physical injury to jaw structures is a highly probable mechanism for most TMD complaints following whiplash-type injuries. The term jawlash was popularized in the media in the 1970s to represent a wide variety of jaw pains, sounds, dysfunctions, and symptoms related to violent, uncontrolled forces that snapped patients’ heads around and misaligned the jaws.

Others say TMD should be considered as a multifactorial bio-psycho-social disorder, and that TMD purportedly caused by a whiplash-type mechanism (acute hyperextension-flexion of the neck) to the TMJ has been shown to be an unlikely event, linked anecdotally and disproved experimentally.

From the insurance industry perspective, the characteristics of patients with TMD that appear to be related to motor vehicle collisions differ from TMD unrelated to motor vehicle collisions not in physical factors but in terms of the psychosocial components. There are significant economic expenses related to whiplash disorders including medical care, disability, sick leave, lost productivity and litigation. In general, patients litigating motor vehicle collision issues present with higher levels of pain, more masticatory muscle tender sites, greater utilization of health care and medications, higher levels of somatization, and higher pain assessments than non-litigating TMD patients. While most people involved in minor motor vehicle accidents recover quickly without any chronic symptoms, some continue to experience symptoms for years after the injury. TMD patients alleging motor vehicle collision causation show greater levels of facial and headache pain, jaw muscle and neck tenderness, and greater sleep disturbance than non-MVA-TMD leading to litigation.

This suggests that litigation is an important factor in these patients. It is prudent to understand the importance of psychological factors in MVA-TMD cases considering the evidence of nonstructural whiplash-related pain being unrelated to the initial injury and independent of the trauma.

Hope for the future

Health care professionals now recognize advances in the understanding of pain and pain management for multifactorial biopsychosocial disorders like TMD. Physicians must better recognize the early signs and symptoms of TMD and understand the importance of early diagnosis and appropriate management, as well as the relationships between TMD and more widespread musculoskeletal pain disorders like fibromyalgia. From a dental perspective, it is hoped that the future will see physicians recognizing the dental literature, and that dentists will continue to participate and lead in research, education, and management of oral facial pain as one of several disciplines acting in a coordinated manner to benefit chronic pain patients. However, in the case of TMD, we will use pain-management skills together with or instead of dental procedures. Advances in our knowledge of pain will further elucidate the many factors interacting in TMD and chronic pain patients, and allow early identification of individuals at risk for chronicity as well as the biological and psychosocial risk factors associated with TMD.

The role of litigation and secondary gain will become better understood, leading to a time when medical and legal concepts of chronic pain causation are more evidence-based and logically related.?

Dr Edwin Bonner BDS MDent is a Specialist Prosthodontist in Dentistry. Since graduating in Johannesburg and moving to the UK, Ed Bonner has had 45 years dental experience in NHS, private and hospital practice, of which 30 years has been as a Specialist Prosthodontist. His expertise is in fixed/ removable prostheses, TMJ dysfunction, oro-facial pain and dental malpractice. He ran a clinic specialising in TMJ dysfunction for many years.

A Sloan Fellow of the London Business School, Ed advises practices in leadership / management, and has written over 1000 articles. Ed has lectured extensively at dental schools and organisations in the UK and South Africa.

He has written 2400 dento-legal expert witness reports, mainly for claimant, in personal injury and negligence.

E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Website: www.bonnerdentalexpertwitness.com