Posts Tagged ‘occlusion’

Splints. Questions to ask

26/09/2010

The TMJ Association: Splints – What you should know (…)

There isn’t an accepted standard of practice for splints. Here is a list of questions you should ask:

  • What is the splint going to do (flat plane or repositioning), and why are you recommending this kind to me?
  • Are you recommending this splint to decrease my pain, reposition my bite or both?
  • What are my other options?
  • What happens if my pain gets worse while wearing the splint?
  • What happens if I develop an open bite (teeth no longer touch)?
  • What proof do you have that this splint will help?
  • Do I wear the splint during the day, night, or both?
  • How long do I have to wear the splint to feel improvement?
  • If the splint doesn’t help, what are the next steps?
  • How many follow-up treatments will be necessary and how much each visit cost?
  • Will insurance cover the cost of the splint and the follow-up treatments?
  • Must I sign a financial contract with you to begin treatment?       (…)

Source: The TMJ Association: Splints – What you should know

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Occlusal Bite Splints. Caveats.

26/09/2010

The TMJ Association – Occlusal Bite Splints: A Help For Many But Not Everyone
(…) The decision of whether a bite splint is a sensible treatment in your particular case is a clinical judgment call rather than a decision that is based on sound, scientifically validated criteria.

If you opt for a bite splint, you should be aware of the fact that not all bite splints are equal. Two major types are distinguished, namely (1) those that maintain the existing jaw relationship, and (2) those whose purpose is to intentionally alter the existing bite for a particular therapeutic intent, such as “capturing the articular disk” or “the realignment of the condyle in the articular fossa”. Occlusal appliances of the first group are also referred to as “stabilization” splints and members of the second group are often called “repositioning” appliances. Neither design has been proven to be incrementally superior over the other with any consistency as far as benefit for the patient is concerned. In terms of negative consequences, however, splints of the second group pose a substantially greater risk of inducing bite changes. When worn for months to years, the resulting bite changes often call for costly bite repair by means of new dental work, orthodontic treatment or even jaw surgery. (…)

Source: The TMJ Association – Occlusal Bite Splints: A Help For Many But Not Everyone

Hypnotic TMJ Therapy: Open and Close. Slowly, gently.

06/09/2010

 

    

   

 

Try it.           (Shock Wave Flash)

http://www.tmj-lessons.com/images/TMJ_Animation.swf

Cephalometric points

05/09/2010

 

  • a) Saddle (S) – Turkish saddle geometric center, set by inspection; 
  • b) Nasion (N) – nasal suture intersection with naso-frontal suture, in the median sagittal plane, set by inspection.
  • c) Porion (Po) – External acoustic meatus uppermost point. Very difficult to set because of other anatomical elements overlapping. To locate it, Miyashita (1996) reference points were used, in which the external acoustic meatus is located posteriorly to the mandible condillar process, above the basion and the axis odontoid process;
  • d) Orbitary (Or) – right orbit cavity contour lower most point;
  • e) Anterior nasal spine (ENA) – median point formed by the extension of both maxillas in the anterior and inferior portion of the nasal floor;
  • f) Posterior nasal spine (ENP) – median point formed by the union of the posterior borders of both palatine bones;
  • g) A (Sub spinal) – anterior maxilla concaveness deepest point, between the anterior nasal spine and the upper dental arch alveolar limit;
  • h) B (Supramenton) – deepest point in the symphysis anterior concaveness;
  • i) Pogonion (Pg) – anterior most point in the mandibular symphysis;
  • j) Tegumentary pogonion (Pgt) – anterior most or most prominent point on the chin soft tissue, in the median sagittal plane;
  • k) Mentonian (Me) – lower most point in the mandibular symphysis contour;
  • l) Gnathion (Gn) – most anterior and inferior point in the mandibular symphysis;
  • m) Articular (Ar) – Intersection point on the external skull base contour with the mandible condillar process;
  • n) Gonion (Go) – most anterior and posterior mandible point in the antero-posterior direction. Located at the ramus posterior border, tangent with the mandible inferior border angle bisectrix;
  • o) Inferior root apex (Ari) – point in the lower most region of the lower central incisive root apex;
  • p) Lower incisive border (BII) – Lower central incisive crown uppermost border region point;

Source: Comparative cephalometric study

Cephalometric planes and lines

05/09/2010

Measuring linear values

  • Posterior facial height (AFP) – Distance from the Ar point to the mandibular plane, in a tangence with the mandibular ramus posterior border (Merrifield, 1989).
  • Anterior facial height (AFA) – Distance between the Me point and its ortogonal projection over the palatine plane. The palatine plane is traced by joining ENP and ENA points (Merrifield, 1989).
  • Facial Height Index (IAF) – set by the AFP/AFA ratio (Horn, 1992).

Measuring angular values

  • a) FMA – Angle formed by the intersection of the Frankfurt horizontal plane (PHF) with the mandibular (MD). The Frankfurt horizontal plane was traced by joining points Po and Or. The mandibular plane by the mandible body inferior border tangent, going through point Me (Tweed; 1954).
  • b) SNA – Angle formed by the intersection of the Saddle-Nasion and Nasion-A lines (Riedel; 1952).
  • c) SNB – Angle formed by the intersection of the Saddle-Nasion and Nasion-B lines (Riedel; 1952).
  • d) ANB – Angle formed by the intersection of the Nasion-A and Nasion-B lines (Riedel; 1952).
  • e) Angle Z – Formed by the intersection of the Frankfurt horizontal plane with the Pg point tangent line and the most anterior lip (Merrifield; 1966).
  • f) Y axis angle – Formed by the Y axis, from point (S) to point Gn, with the Frankfurt horizontal plane (Downs; 1948).
  • g) SN-GoGn Angle – Formed by the intersection of the mandibular plane (GoGn) with the S-N line.
  • h) IMPA angle – mandibular plane intersection with the lower central incisive long axis


Source: Comparative cephalometric study

TMJ muscles

05/09/2010

• Figure 10-8 The lateral pterygoid is the main protrusive and opening muscle of the mandible. It is arranged in parallel-fibered units that allow for greater displacement and velocity than that of the multipennated closing muscles. The lateral pterygoid muscle is divided into two parts. The inferior part arises from the outer surface of the lateral pterygoid plate of the sphenoid and the pyramidal process of the palatine bone. The superior part originates from the greater wing of the sphenoid and the pterygoid ridge. The fibers of the upper and lower heads course posteriorly and laterally, fusing in front of the temporo-mandibular joint. They insert into the anteromedial aspect of the condylar neck. Some of the fibers insert into the most anterior medial portion of the disk, but most of the lateral pterygoid fibers insert into the condyle. Translation of the condylar head onto the articular eminence is produced by contraction of the lateral pterygoid. 
 

• Figure 10-7 The digastric muscle is a paired muscle with two bellies. The anterior belly attaches to the lingual aspect of the mandible at the parasymphysis and courses backward to insert into a round tendon attached to the hyoid bone. Contraction produces a depression and retropositioning of the mandible. The mylohyoid and geniohyoid muscles contribute to depressing the mandible when the infrahyoid muscles stabilize the hyoid bone during mandibular movement. These muscles may also contribute to retrusion of the mandible. The temporalis muscle is broadly attached to the lateral skull. The muscle fibers converge to insert on the coronoid process and anterior aspect of the mandibular ramus. The posterior part traverses anteriorly then curves around the anterior root of the zygomatic process before insertion. The posterior part of the temporalis contributes to mandibular retrusion. 

• Figure 10-6 The masseter and medial pterygoid muscles have their insertions at the inferior border of the mandibular angle. They join together to form a sling that cradles the ramus of the mandible and produces the powerful forces required for chewing. The masseter muscle has been divided into a deep portion and a superficial portion.

Source:  Temporomandibular Disorders Download Chapter 10 (1MB)

http://web.squ.edu.om/med-Lib/MED_CD/E_CDs/oral%20medicine/docs/ch10.pdf

Occlusion drawings

04/09/2010

Temporalis

 

Masseter

 

Rotation-translation

 

How a normal jaw opens and closes

Jaw is closed

 

How the articular disc behaves during normal jaw opening

 

Jaw opens

Source:  http://www.doctorspiller.com/occlusion.htm

Occlusion – more than how teeth come together

04/09/2006

The subject of occlusion has been made more complicated than it has to be. It seems that we are trying to explain everything by the way teeth come together, whereas the most comfortable patients always have their teeth apart. The occlusion confusion has distracted dentists from focusing on the more serious problem of patients grinding and clenching their teeth. Would we have any problems related to occlusion if patients did not clench and grind?  I think very few. The first line of defense for TMJD and oral facial pain is the GP’s understanding of the relationship between occlusion, the stomatognathic system, and DCS prevention. 
from The Truth About Occlusion 
Gene D. McCoy, D.D.S.   Download 528Kb

Which Concept on Occlusion Is Correct?

03/09/2006

Gordon Christensen, in his annual review New Directions in Dentistry, stated:

“There is extreme controversy about which concept of occlusion is correct, and I do not see any relief to that controversy.”46
In a subsequent article, he wrote that “the profession is in major chaos relative to occlusion.”47
Frank Spear recently wrote that “a byproduct of increased interest in occlusion has been a renewed debate about which occlusal philosophy is correct.”48
Why is this question so difficult to answer?
Because of the different interpretations of the word occlusion, we are not quite sure what the question is asking.
  • If it is asking the best way teeth should touch each other and when, the answer would be that the contact should be confined to the tip of the cusps, and that contact should occur only during swallowing.
  • If it is asking the best way teeth should touch each other during mastication, the answer would be that they shouldn’t.
  • If it is asking for the most efficient way the stomatognathic system should function, the answer would be: without heavy compressive vertical and lateral forces (DCS).
But the question is not focused on any of these interpretations.
What Christensen and Spear are referring to are the two different philosophies taught at the LVI and at the Pankey Institute: the neuromuscular methodology, on the one hand, and the gnathological approach, on the other.
But wait a minute!
These are not concepts on occlusion. These are two different methods of rehabilitation and/or reconstruction to be used when patients are in trouble.
So now the word occlusion has a fourth interpretation. 
Is one method better than the other? That is not the important question.
What we should be asking is:
What is the best way that general practitioners should be doing their work in order to minimize the deleterious effects of DCS so that patients don’t have to go into rehabilitation?
Why general practitioners? Because it is the GPs who are doing the vast majority of the work. Very few patients go into rehabilitation or reconstruction—probably less than 1%. The majority of dental work that is performed each day throughout the world is by increments—a crown here, an amalgam restoration there, facial composites, or some fixed bridgework. Since this is reality, what is the best way GPs can perform this incremental work, maintain the health and effi ciency of the stomatognathic system, and prevent DCS? That is what we really want to know if we are going to interpret “concept on occlusion” objectively. 
What are the guidelines? GPs should: 
  • 1. Be alert to the signs and symptoms of DCS. 
  • 2. Thoroughly explain DCS to their patients. 
  • 3. Determine if an equilibration is necessary. 
  • 4. Determine if a guard is necessary. 
  • 5. Mimic the natural design of teeth when delivering dental prostheses to the mouth. 
from The Truth About Occlusion 
Gene D. McCoy, D.D.S.   Download 528Kb


The Management of Dysfunction

02/09/2006

The presence of deformations in the oral environment should stimulate a dialogue between the dentist and patient to determine if the patient is currently grinding and/or clenching his or her teeth, or whether this damage occurred during a prior stressful period. 

Often a patient will deny any awareness of DCS (dental compression syndrome), but upon returning will say something like, “You know, since you brought it to my attention, I catch myself clenching all the time.” 
Management of DCS (dental compression syndrome) begins with awareness and proceeds with a three-step treatment plan, which consists of education, equilibration, and guard therapy. 
  • Step 1: Education. Dental healthcare providers must teach their patients  everything they know about DCS (dental compression syndrome) in the simplest terms. Patients need to understand that teeth should only touch upon swallowing, and they should also know the resting position of the mandible (lips together, teeth apart). The list of etiological agents should be reviewed. Patients should be asked to monitor their jaw position during waking hours and be sensitive to headaches and tension in muscles of mastication upon waking. If it is obvious that patients are affected by DCS but are indifferent to the problem, their dental records should indicate that, and no further treatment should be initiated. However, if patients are aware of the problem and want to eliminate or reduce it, the next step is to analyze the occlusion in order to determine if the morphology of certain teeth needs to be modified. 

from The Truth About Occlusion 
Gene D. McCoy, D.D.S.   Download 528Kb