Parafunctional Analysis in Diagnostic and Restorative Dentistry
Michael J. Melkers, DDS, and Jeanine M. McDonald, DDS
The progression in diagnostic and restorative dentistry from subjective to objective gathering of data and its application in treatment has been a continual evolution in the profession. From early applications and refinements in radiography, cariology, oral pathology, and periodontology, the dental profession has been involved in an ongoing effort to minimize the subjective in an effort to provide more definitive, conservative, and appropriate care.1 One of the greatest unmet challenges in diagnostic dentistry and its applications in restorative treatment planning is a practical and economical method for evaluating parafunctional activity.
One of the ways that parafunction has been addressed by the dental profession has been through occlusal splint therapy. Dylina2 summarized the purpose of occlusal splints to:
• relax the muscles
• provide pain management
• allow the condyles to seat into centric relation
• prevent the teeth and associated structures from parafunctional occlusion
• provide diagnostic information.
This can be distilled down to defining the purpose of occlusal splints as being palliative, protective, and diagnostic.3 However, the current method for compiling diagnostic information from splints can be enhanced.
Historically, in-splint therapy practitioners have used articulating paper or film to record where patients occlude and contact in protrusive and lateral excursive movements as directed by the practitioner.4 Patients are either instructed to close into a habitual position or guided to tooth-to-splint contact in a desired condylar position. Those contacts are then recorded with the articulating medium. Excursive contacts on the occlusal orthotic are recorded in a similar manner. While this method of recording can provide valuable information for the refinement of desirable contacts on the orthotic surface, it does not provide information regarding parafunctional activity and its potentially destructive forces.
When a debilitated dentition is examined, the destruction from tooth-to-tooth contact is evident. Attrition and loss of tooth structure in various locations can be observed, including, but not limited to, ledging of the lingual surface and incisal and cuspal wear (Figure 1). While hand-articulated diagnostic casts or mounted occlusal analysis can be used to evaluate and match these maxillary–mandibular contacts, it does not provide us with clear and objective data regarding the intensity and direction of the parafunction. This method of analysis may also require that there be a sufficient amount of structural loss to objectively define the wear patterns observed on the diagnostic casts. This method would be limited to a reactive rather than a proactive approach regarding attritional loss of tooth structure. A new method for parafunctional analysis allows for the evaluation of not only the advanced, debilitated dentition but also a dentition that has not yet exhibited significant wear patterns.
The transition from occlusal to parafunctional analysis involves a change in mindset from observing what the patient can do voluntarily in a clinical setting to recording what parafunctional activity actually occurs (Figure 2 and Figure 3).5 There are patients who can exhibit a great range of motion clinically but do not present with any subjective symptoms or objective signs of wear that would support that this range occurs with any intensity or duration. Conversely, patients frequently present with extensive wear patterns and loss of tooth structure. When asked to replicate the excursive movements that appear to be responsible for these wear patterns, the patient may be unable to do so.6 What is required is a simple, economic, and definitive method for recording and evaluating this activity.
The parafunctional analysis involves the application of a recording media to the entire occlusal surface of the orthotic device at the delivery of the appliance (Figure 4). The recording media, a simple over-the-counter, non-toxic permanent marker is of absolute minimal film thickness. This is critical as it will allow for parafunctional activity to be recorded in the marked surface before wear patterns are significant enough to create divoting in the acrylic.7 If divoting is allowed to occur on the surface of the orthotic, resistance points may influence the parafunctional patterns themselves (Figure 5).8 This media may be reapplied as needed at subsequent adjustment appointments for continued evaluation of parafunctional activity as well as any changes in the intensity or range of the activity. The permanent marker can then be considered a “reverse articulating paper” as it will allow the recording media to be worn away by the parafunctional activity rather than have the recording media or articulating paper applied to the surface of the orthotic during attempts to replicate these acts in the operatory (Figure 6).
A 38-year-old female patient presented with a chief concern of near-constant headaches for several years. The pre-clinical interview revealed that the headaches presented bilaterally in the body of the temporalis but more so in the anterior bands. The patient also reported that throughout the day, the pain was also noted behind the eyes, again bilaterally.
On clinical examination the patient exhibited a normal range of motion in all excursions. No joint noise or symptoms were noted on palpation or osculation. Examination and palpation of the musculature of the head and neck revealed replication of symptoms in the main body and anterior bands of the temporalis, as previously reported by the patient. Upon restriction of movement in protrusive excursion, the patient noted bilateral symptoms consistent with the lateral pterygoids. Further muscle palpations revealed bilateral symptoms in the scalines and also the upper trapezius. After 15 minutes of deprogramming using a relined anterior midpoint stop appliance, no slide was noted from the first point of contact to the maximum intercuspation position using passive observation as well as active bimanual manipulation.9 Differential diagnosis can include myositis induced by parafunctional activity as well as induction by functional interferences. Clinical curiosities include the direction in which the suspected parafunction will manifest and/or with the removal of which occlusal interferences will the parafunction cease.
After occlusal orthotic therapy using an anterior midpoint stop appliance, the patient reported full resolution of headaches and muscle symptoms. She also observed that a “soreness” of her upper teeth, which she had not previously disclosed, had also resolved. Clinically, the patient continues to present with centric relation being coincident with maximum intercuspation position. At this point in treatment, the appliance has satisfied two of the three criteria of occlusal orthotic therapy. It has resolved the patient’s symptoms (palliative), and it has protected the patient’s dentition (protective). Neither of these criteria can be connected to any parafunctional act beyond circumstantial inference. While the resolution of the symptoms would be consistent with the removal of the influence of parafunction with intensity, without further information there is no definitive evidence that the parafunction actually occurred.
DIAGNOSTIC APPLICATION OF PARAFUNCTIONAL ANALYSIS
Upon clinical evaluation of the surface of the orthotic, wear patterns can be observed in the reverse articulating paper or permanent marker coating (Figure 7). These reverse articulation marks would appear to be consistent with a protrusive parafunctional pattern. It can be noted that at the most anterior point of the pattern as well as the most posterior point, a sliver of the permanent marker is still evident. This unaltered mark corresponds to the midline incisal embrasure and would support that at the initiation, as well as the terminal limit of the protrusive stroke; the parafunctional act is almost purely protrusive in nature. Upon further evaluation, wear can be noted in the middle third of the protrusive stroke, disrupting the anterior-posterior sliver of articulating medium. This may be consistent with the worn surfaces that are evident on the maxillary and mandibular cuspids, which would be in contact at that point if lateral excursive parafunction occurred in addition to the protrusive act (Figure 8 and Figure 9). Finally, red articulating film was introduced and the patient was instructed to replicate the protrusive movement that was evident in the reverse articulating media (Figure 10).
The broken protrusive marks in red serve two purposes. First, they serve as a final confirmation of the validity of the parafunctional analysis by filling in with articulating paper marks the reverse articulating marks that were worn away in parafunction. This provides parafunctional confirmation by:
• resolution of symptoms consistent with the differential diagnosis
• objective presentation of the parafunctional activity in the wear patterns in the applied permanent marker
• confirmation of that activity by replicating and marking it clinically.
Second, additional information is also provided by the clinical application of the red articulating film to the wear areas. The uneven nature of the marking of the pro-trusive stroke or “skip divoting” would give some indication of the intensity required to not only wear away the permanent marker but also gouge and push the acrylic in the occurrence of the parafunctional act (Figure 11). The “skip divots” occur as the patient has intensity of closure or clenching at the same time as a parafunctional or protrusive range. The intensity of the temporal activity is great enough to indent the surface of the acrylic while the action of the musculature (lateral pterygoids, etc) responsible for the protrusive act is great enough to still allow for movement. The acrylic is then indented and/or pushed until the protrusive motion is great enough to move the mandible forward. Over time, with sufficient intensity and roughened incisal edges, wear patterns become more evident and pronounced. The combination of the reverse and traditional articulating marking media reveal those areas of the orthotic, as well as perhaps the sharp, uneven incisal edges that may require adjustment and refinement to remove interference.10 Left unaddressed, these interferences can become significant enough resistance points (Figure 12) to allow for the return of muscle symptoms and even perpetuate the continued loss of tooth structure.
Through parafunctional analysis facilitated by the reverse articulating media, some conclusions can be made:
• The differential diagnosis of myositis induced by parafunction has been confirmed.
• The direction and relative intensity of the parafunction has been confirmed.
• It has been further confirmed that removal of potential interferences of the dentition did not lead to abatement of the parafunction.
With this information we can provide our patient with sound treatment options based on definitive data. For the patient in this example, appropriate recommendations might include continued orthotic therapy for palliative and protective applications. Mounted occlusal analysis could also be offered as a diagnostic treatment option for evaluating any potential changes to the dentition or occlusal scheme that might be appropriate to minimize the parafunctional forces when the orthotic is not in place.11
PARAFUNCTIONAL ANALYSIS AIDING ORTHOTIC ADJUSTMENT
Parafunctional analysis should not be restricted to a posttreatment confirmation of differential diagnosis. Ongoing parafunctional analysis can aid in adjustment and refinement during occlusal orthotic therapy. By identifying occlusal contacts, both desirable and undesirable, adjustment of the orthotic can become much more efficient. This in turn will translate to improved patient comfort and compliance with orthotic therapy.
In fabrication of a full-arch mandibular orthotic appliance, care is taken to achieve all of the desired occluding and excursive marks with the maxillary dentition. With the condylar locks engaged on the articulator, equal and simultaneous occluding contacts are sought throughout the appliance (Figure 13). As the device is further refined and the condylar locks are released, the anterior discluding contacts are developed (Figure 14).12 These contacts, using programmed occlusal instrumentation, will aim to replicate the desired contacts that provide protection during clinical parafunctional excursions.
Once the device is delivered to the patient, these contacts can be verified and further refined (Figure 15). Again, simultaneous and equal contacts are achieved throughout the arch and the desired anterior guidance is refined (Figure 16). Before dismissing the patient, the entire occluding surface of the orthotic is coated with the permanent marker, which will serve as the reverse articulating media (Figure 17).
Because one of the purposes of occlusal orthotic therapy is to allow the condyles to seat in centric relation,2 it should be noted that the mounted casts on which the orthotic was fabricated may not have accurately represented centric relation but rather as accurate of a mounting as was possible for this patient after deprogramming. As condylar seating occurs the contacts that present clinically will differ from those that were present during initial fabrication of the orthotic. The distribution of the maxillary contacts on the orthotic will change as well as the excursive contacts, both desirable and undesirable.
As the patient returns for subsequent orthotic adjustments, the areas that have been worn away in the reverse articulating marks represent occluding and excursive contacts (Figure 18). Because these wear areas are not present throughout the arch, they are indicating high spots, or interferences, on the orthotic that will need to be adjusted to facilitate a return to simultaneously distributed contacts throughout the appliance. As these adjustments are made and marked in red with articulating paper, the areas in which the reverse articulating marks have been worn away represent the areas that the patient is contacting during parafunctional excursive movements (Figure 19). These excursive areas can either be removed in undesirable areas, such as posterior excursive contacts, or refined in desired anterior contact areas (Figure 20). Through subsequent markings and adjustment appointments, the orthotic can be refined to completion.
The profession of dentistry has continued to explore more efficient, meaningful ways to assemble data from patients so treatment planning and ultimately patient care is enhanced. The existing methodologies of splint therapy and its applications in diagnostic and restorative dentistry have served the profession well. The evolution of this therapy with parafunctional analysis and reverse articulating markings can provide a means for increasing the efficacy and efficiency of these existing modalities. The information that can be obtained through the application of these new concepts can serve to continue to increase the objective and decrease the subjective data in our clinical decision-making process.
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11. Melkers MJ. Nuts & Bolts Occlusion—Occlusal Instrumentation Simplified. Dental Town Online Continuing Education Module. 2006.
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|About the Authors|
|Michael J. Melkers, DDS |
|Jeanine M. McDonald, DDS |