How thorough was your education about occlusion in dental school? If it was typical, you learned occlusal terminology, and you might have accomplished an occlusal splint and an occlusal equilibration. Have you put that information and experience into use since graduation? Most dentists have not. I suggest that observation of occlusion and treatment of pathogenic or pathological occlusal conditions is the most neglected area of dentistry, with a close runner-up being treatment of periodontal disease. It has been my observation that most practitioners are happy to find that a restoration stays in place and is acceptable from an esthetic standpoint. In-depth observation and evaluation of occlusion usually is not accomplished or is done superficially. Recently, I watched a multiple-unit fixed prosthesis being tried in a patient’s mouth, evaluated for fit and color, and cemented without any occlusal adjustment before or after cementation. Regardless of the articulator used, I have yet to see such a restoration come from any laboratory without need for careful occlusal adjustment at seating and after a few weeks of service in the mouth.
I will discuss the several commonly occurring situations in dental practice when occlusal equilibration should be considered and, if found to be necessary, when slight or comprehensive occlusal equilibration should be accomplished.
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SITUATIONS REQUIRING OCCLUSAL EQUILIBRATION
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The following clinical situations occur frequently in dental practice. Each situation is somewhat different, but the basic principles of occlusal stability and reduction or elimination of potential pathogenic conditions should be considered and treated if necessary. I described the normally occurring characteristics present in a healthy occlusion in a recent column.1
Prerestorative/ prosthodontic occlusal equilibration.
I suggest that this procedure should be accomplished several times each practice day.
If occlusal prematurities exist in the preoperative situation and typical simple-to-complex restorative procedures are accomplished without removal of occlusal prematurities, the new restorations may increase occlusal disharmonies and subsequent occlusal problems. An analogy is a dirt road with deep ruts in it. Driving out of the ruts is difficult or sometimes impossible. Similarly, if occlusal prematurities are present in the preoperative state, the new restorations must adapt to the incorrect occlusion, and any subsequent attempts at occlusal equilibration are more difficult.
Postoperative restorative/ prosthodontic occlusal equilibration.
How many restorations have you placed in your career with perfect occlusal contacts and without any occlusal prematurities? Most practitioners will agree that they infrequently receive restorations with perfect occlusal contacts directly from laboratories. Finding occlusal prematurities on direct restorations is relatively easy, since the restorations are retained in previously cut tooth preparations. The challenge is remembering to carry out a minimal occlusal equilibration when finishing the direct restoration.
When placing indirect single restorations, occlusion should be evaluated carefully before cementation so any major occlusal equilibration can be accomplished, and the restoration should be finished and polished before seating it. The only exception to this statement is seating of weaker all-ceramic restorations, in which case the restorations should be adjusted for occlusion after cementation.
When seating multiple units of indirect restorations, I suggest accomplishing preoperative occlusal equilibration, further equilibration of the teeth and restorations at seating, and additional equilibration after about six weeks of service in the mouth. This concept helps ensure that the occlusion of the newly restored teeth will not contribute to tooth, restoration or periodontal failure.
Postorthodontic occlusal equilibration.
This subject is one of my most frequently occurring pet peeves. After an orthodontic patient has undergone months to years of orthodontic therapy, the brackets, bands, wires and so forth are taken off, and seldom are the newly positioned teeth equilibrated to their orthodontically established occlusal contacts. The result is predictable relapse of the teeth’s positions to somewhere between their pre-orthodontic therapy locations and their positions created by the orthodontic therapy.
If the orthodontist, pediatric dentist or general practitioner responsible for the orthodontic therapy is not interested in accomplishing the postoperative equilibration, a practitioner who is competent in accomplishing this procedure should see the patient within hours of removal of the orthodontic movement devices to avoid movement of the teeth caused by unavoidable occlusal prematurities.
The principles of occlusal equilibration, understood by the treating practitioner, can guide in the simple reshaping of teeth required by this conservative esthetic procedure.
Occlusal equilibration as a part of treatment for bruxism or clenching.
A significant percentage of patients seeking dental care experience bruxism or clenching.2 Although removal of occlusal prematurities is controversial, most practitioners agree that the procedure reduces patients’ tendency to aggressively continue their destructive habit. At the least, worn-in chewing patterns can be disrupted by occlusal equilibration, thus potentially reducing the possibility that further atypical wear patterns will continue to be accentuated.
Occlusal equilibration for esthetic reasons.
It is not unusual to see veneers or crowns placed on anterior teeth because some of the involved teeth were slightly longer or shorter than the adjacent teeth or because some teeth were slightly malpositioned. To avoid radical treatment, conservative recontouring of teeth, slight gingival recontouring, reshaping of slightly malpositioned teeth and, perhaps, bleaching should be accomplished. These conservative therapies can avoid placement of restorations and the inevitable replacement of those restorations some years later. The principles of occlusal equilibration, understood by the treating practitioner, can guide in the simple reshaping of teeth required by this conservative esthetic procedure.
Occlusal equilibration as a part of temporomandibular dysfunction.
The most frequently used procedures for treatment of temporomandibular dysfunction (TMD) are occlusal splints and occlusal equilibration.3 The frustrating aspect of this statement is that many practitioners will not treat simple muscular TMD, and they do not accomplish occlusal equilibration in their practices. I suggest that dentists become competent in simple occlusal equilibration and that they treat simple cases of muscular TMD.
Occlusal equilibration as a part of periodontal therapy.
This subject is genuinely controversial. The opinion commonly expressed by many periodontists and general dentists treating periodontal disease is that there is not a relationship between occlusion and periodontal breakdown. This belief is written as a near-axiom is dental texts. A further challenge in that most general dentists do not treat periodontal disease or have much interest in it.4 This problem has been verified strongly by my experience when I ask large groups of practitioners about their involvement with periodontics.
At the risk of having to respond to the critiques of some readers, I will express my clinical observations on the relationship of occlusal trauma to periodontal conditions. I have formed these opinions after placing thousands of units of crowns, fixed prostheses and removable partial dentures. If I inadvertently leave occlusal prematurities on restorations, it is just a matter of time until I see periodontal manifestations of the occlusal trauma. The most common sign will be widened periodontal ligament space, and the most frequently occurring symptoms will be pain in the affected tooth or teeth and eventual pulpal death if the occlusal trauma is allowed to continue. If the prematurities have existed for months or years, the bone support will be reduced, as observed on radiographs.
In a recent in-depth discussion with Dr. Alfred Seltman, a practicing periodontist for many years, I was interested to see radiographic images from many cases he has treated over several decades in which the original periodontal bony support of teeth was nearly terminal at the origin of treatment. By frequent minimal occlusal equilibration for these patients, not only was the original bone level preserved but, astonishingly, the bone increased over the years, the teeth became less mobile, and tooth extraction was avoided.
Such statements as the preceding ones are contrary to popular belief in the profession. Because of the controversy, I encourage additional long-term investigations on the relationship of occlusion to periodontal health. In the meantime, I will continue to consider occlusal equilibration to be a significant factor in preserving and improving periodontal health and bone support.
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SUMMARY
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Observation of occlusion, providing patient education about occlusion and treatment of occlusal conditions sadly are neglected in the profession. Occlusal equilibration is one of the major treatments for occlusally oriented diseases, and I estimate that this procedure is not accomplished frequently by many practitioners. I have discussed the conditions needing occlusal equilibration and suggested procedures for the conditions. I encourage practitioners needing education in occlusion to seek it.
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SITUATIONS REQUIRING OCCLUSAL...
SUMMARY
