Clinical Cases
Introducing clinical cases to this website is problematic.  We have endeavored to keep to scientific discipline in
the presentation of this site and individual clinical cases have, by their very nature,  limited scientific validity.  
However, in the years we have been in controlled clinical and laboratory trials at Loughborough University, there
have been a series of very successful and, to a great extent, remarkable clinical results.  A few of these cases
are included in Power Point (PPT) format for your review as an illustration of the clinical results that have been
obtained using this model of dental occlusion.  The presentations are best viewed in "slide show" format with
progressive display of integrated portions of each slide for better understanding of the material.

It is important to recognise that our concept of muscle function in this discipline calls for maximal coordinated
muscle effort on closure.  The concept of limiting muscle function on tooth contact is unique to a few dental
disciplines and is not, in our concept and/or thoughts, the healthier mode of muscle function.  In other
neuromuscular and physiological concepts (sports medicine is an excellent example) healthier joints are
maintained by range of motion and strength exercises of the supporting musculature.  We recognize the same
dynamic working in the masticatory system and see no need to reflexly inhibit muscle function.

While we recognize the diagnostic and immediate pain relief value of anterior appliances and/or jigs (NTI is an
excellent example), they are not indicated for long term use.
Wright The PGO (posterior guided occlusion)
concept and appliance evolved through many years of study and practice.  It is easier to place and maintain two
fully balanced areas of contact and function than eight.  Consequently, when some practitioners use an anterior
jig, we will use a full coverage mandibular splint with contacts on the second molars to break the muscle spasm
cycle.  As the muscles relax and recondition to coordinated activity, we then adjust the splint to a more evenly
distributed occlusal dynamic that supports that individuals neuromuscular comfort and better muscle function. .  
According to recent literature, using this posterior support and guidance is much less apt to induce intra-capsular
issues than anterior jig style appliances.
Balancing Side Protection  

This philosophy does not suggest that anterior guidance is inappropriate.  We believe that when existing natural
teeth in harmonious function are involved in a dental restoration, the occlusal form should be maintained.  The
design and dynamics of teeth in healthy occlusal function are reflected in the bony anatomy of the TMJ and any
alteration of this design will cause an adaptive change in these anatomical structures.  Repeated studies in the
last 15 or so years indicate between 68 - 100% of individuals with comfortably adapted occlusal function have
cross arch balancing contacts that support and stabilize the gliding TM joint in dynamic function. To arbitrarily
remove this guide can overload the gliding joint and may cause serious inflammatory change in the ensuing
adaptive process.

We do not support the concept of mutual or simultaneous contact of all teeth in Centric Relation (retruded)
Occlusion (CRO).  The studies at Loughborough University support the concept that the "neutral" position from
which all dynamic movements on the mandible are initiated and finished is Maximal Intercuspal Position (MIP).  In
MIP most people do not have mutual contact of posterior and anterior teeth (Beyron, Henry, 1964: 22, 597 – 678,
07Acta Odont. Scandinavica).  Since MIP is anterior to CRO, how can there be mutual or simultaneous contact in
this retruded position?

Muscle function seems best (more coordinated and comfortable) when there are stable "centrum" areas of
contact on the posterior teeth which allow the individual to "slide" to touch or engage an anterior tooth contact
which may provide a disoccluding guide.  However, many individuals maintain a group function in the contact of
anterior teeth with no disoccluding guidance.

We recognise that the patients' experience of pain, especially in patients in a chronic state, has a complex
aetiology.  We do not claim with 100% certainty that the improvement in symptoms of these patients is entirely
due to the alteration of their occlusion.  Our treatment regimen also includes a great deal of attention to any
emotional, behavioural and pharmacological aspects of their problem.  However, we routinely record and see
improvements in more objective measurements such as TM joint function, range of motion and comfort of
muscular function and the general sense of wellness of the afflicted individual.  

This data collection and correlation is ongoing; involves more than 60 consecutive subjects; has given very
positive indication for the successful use of a fully balanced, posterior guided appliance in treatment of TMD/TMJ
issues and is providing the basis for the next series of formal EMG studies at Loughborough University.  These
studies will commence in January 2010.
The following Power Point Presentations are included as examples of the possibility of
clinical treatments when dedicated discipline is used in delivering and maintaining fully
balanced occlusal splints.  These files are large and may take a few minutes to download.

Please view in "Slide Show" format for a better visual
and learning experience.
1. Dr. Henry M. Tanner - Mandibular Splint.  This appliance is often called a "Tanner" appliance
and in the 30 or so years that I was privileged to study, teach and work with Dr. Tanner, I seldom
saw him add an anterior ramp for dis-occlusion purposes.  The splints in this presentation are from
his slide collection and are reminiscent of those he commonly delivered.
Tanner - Stable Centrums

2. Dr. Ron Presswood - This series of slides presents our experience over a ten (10) year period
of observing splints with stable centrum guides on which the patient did not brux.  There is much
discussion about the difference between the noxious aspects of bruxing and clenching which, from
a physiological perspective, remains unsupported scientifically.  The next series of controlled
studies at Loughborough University will examine the impact of centrum contact on bruxing
tendencies.  Clinically, patients that clench and do not brux report much less myofascial pain.  This
series of slides shows the stability of centrum, clenching, contacts over time.  All of the patients
have remained free of pain complaints. The splints were not routinely adjusted to centrum contact.
Photographs used with permission.  
Stable Centrums Over Long Periods of Time

3. Ron Presswood - This woman had been in the care of several CMD specialists and had been
referred to me by a neurological medial doctor. I offered to monitor her progress while in the care
of another dentist, a pain specialist.  After a year of our observation with little improvement, she
asked that we assume responsibility for her care. At that time we made a PGA.  Within days she
was much improved and within weeks resumed much of her "normal" life style which had been
absent for the previous five or so years. Photographs used with permission.
5 Years of Pain

4. Ron Presswood - This patient is in her 3rd year of complaint and is being treated with a fixed
appliance that opened her occlusal vertical dimension and held her "forward". Her pain resolved in
a few weeks.  She returned to her natural dentition after minor occlusal adjustment (incisal
reshaping) with no further compliant. Photographs used with permission.
Passive muscle splint,
much pain.

5. Ron Presswood - Patient with non-responsive trigeminal neuralgia, referred by neurological
medical doctor.
Trigeminal neuralgia response

6. Ron Presswood - Patient is mid 30's, post orthodontic with major facial pain.  Diagnostic
process by CMD pain specialist involved an anterior displacement splint which she wore for almost
two years.  Planned surgery, bilateral subcondylar osteotomy, was not acceptable to patient.  
Progressive and dynamic PGA care allowed for adaptation to good intercuspation and occlusal
function without discomfort or pain and without the need for surgery.
Adaptation and reposition of

7. Ron Presswood - Patient is mid 50's complaining of disabling pain and upcoming medical,
possibly surgical,  intervention.  Exam is positive for TMD.  Suggest a trial PGA splint.  Almost
immediate response.  Back to playing tennis and no future medical care.
Immediate relief of severe
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