READERS'ROUNDTABLE
lateral pterygoid muscle palpation.16 The statement about the physiological status within the muscle, that is, level of oxygenation, is pure speculation with no measure of this parameter. 3. Last, the clinical treatment of temporomandibular disorder patients with an irreversible procedure such as “(1) reshaping the teeth so that there are no longer any noxious contacts” in the OccEusal Therapy treatment modality section of the article, has been discouraged by the literature. The American Dental Association sponsored two major symposiums in 1978 and a follow-up in 1988; the published consensus findings of both concluded that this procedure would be contraindicated in a patient with masticatory muscle pain.s-1° Unfortunately, this article will be used by some clinicians to justify irreversible procedures on their patients, based on the author’s proposed objective tests, that is, “muscle palpation” and “the stress test with a leaf gauge.” The use of the leaf gauge has been accepted and utilized in clinical dentistry as an adjunct to obtaining a centric relation interocclusal record. However, Donegan et a1.17 have cast some doubt on the effect of the leaf gauge in altering masticatory muscle activity; furthermore, this device has not undergone adequate testing in controlled experiments to substantiate its use as a diagnostic aide. THE JOURNAL OF PROSTHETIC DENTISTRY readership should be aware that Dr. Long’s article is simply an opinion of the author and, at best, poorly supported by the scientific literature. JOHN W. STOCKSTILL, DDS, MS JOHN F. BOWLEY, DDS, MS ADULT RESTORATIVE DENTISTRY UNIVERSITY OF NEBRASKA MEDICAL COLLEGE OF DENTISTRY 40~~ AND HOLIPREGE LINCOLN, NE 68583-0740
CENTER
REFERENCES 1. MacDonald
2.
3.
4. 5.
6.
I. 8.
9.
10.
11. 12.
THE
JW, Hannam AG. Relationship between occlusal contacts and jaw-closing muscle activity during tooth clenching: Part I. J PROSTHET DENT 1984;52:718-29. MacDonald JW, Hannam AG. Relationship between occlusal contacts and jaw-closing muscle activity during tooth clenching: Part II. J PROSTHET DENT 1984;52:862-7. Wood WW, Takada K, Hannam AG. The electromyographic activity of the inferior part of the human lateral pterygoid muscle during clenching and chewing. Arch Oral Biol 1986;31:245-53. Wood WW. Medial pterygoid muscle activity during chewing and clenching. J PRO~THET DENT 1986;55:615-21. Gibbs CH, Mahan PE, Wilkinson TM, Mauderli A. EMG activity of the superior belly of the lateral pterygoid muscle in relation to other jaw muscles. J PROSTHET DENT 1984;51:691-702. Lund JP, Widmer CC. An evaluation of the use of surface electromyography in the diagnosis, documentation, and treatment of dental patients. 3 Craniomandib Disord 1989$125-37. Berry DC. Occlusion: fact and fallacy. J Craniomandib Pratt 1986;4:5464. Griffiths RH. Report of the president’s conference on the examination, diagnosis, and management of temporomandibular disorders. J Am Dent Assoc 1983;106:75-7. Ohrbach R, Gross A. Summary of the workshop on temporomandibular disorder sponsored by the American Dental Association. 3 Periodontal 1989;60:222-4. Laskin D: Greenfield W, Gale E, et al. President’s conference on the examination, diagnosis, and management of temporomandibular disorders. Chicago: American Dental Association, 1982. Johnstone DR, Templeton M. The feasibility of palpating the lateral pterygoid muse1e.J PROSTHETDENT 1980;44:318-23. Dworkin SF, LeResche L, DeRouen T, Van Korff M. Assessing clinical
JOURNAL
OF PROSTHETIC
DENTISTRY
13.
14.
15.
16. 17.
signs of temporomandibular disorders: reliability of clinical examiners. J PROSTHETDENT 1990;63:574-9. Seligman DA, Pullinger AG, Solberg WK. Temporomandibular disorders. Part III: occlusal and articular factors associated with muscle tenderness.J PROSTHETDENT 1988;59:483-9. Droukas B, Lindee C, Carlsson GE. Occlusion and mandibular dysfunction: a clinical study of patients referred for functional disturbances of the masticatory system. J PROSTHET DENT 1985;53:402-6. De Last A, van Steenberghe D, Lesaffre E. Occlusal reIationships and temporomandibular joint dysfunction. Part II: correlations between occlusal and articular parameters and symptoms of TMJ dysfunction by means of stepwise logistic regression. J PROSTHET DENT 1986;55:116-21. Stockstill JW, Gross AJ, McCall WD. Interrater reliability in masticatory muscle palpation. J Craniomandib Disord 1989:X143-6. Donegan SJ, Carr AB, Christensen LV, Ziebert GJ. An electromyographic study of aspects of ‘deprogramming’ of human jaw muscles. J Oral Rehabil 1990;17:509-18.
Repb To THE EDITOR: This is my response to the letter of Dr. John Stockstill and Dr. John Bowley. The last sentence in the letter from Drs. Stockstill and Bowley states that “THE JOURNAL OF PROSTHETIC DENTISTRY readership should be aware that Dr. Long’s article is simply an opinion of the author and, at best, poorly supported by the scientific literature.” I have no reservation in accepting their statement. It is true. I have been treating patients who have occlusal problems for 48 years. During those years the pendulum has swung from occlusal treatment being almost the only treatment for TMJ problems until now it has gone so far in the other direction that many are afraid to make “irreversible changes” in the occlusion at all, as if that isn’t happening during almost every restorative procedure. This article is on diagnosis, not treatment. An article on treatment is waiting publication in the Journal. I have learned that when I get a positive response from the two tests described I can reverse that response by proper occlusal treatment or the insertion of an occlusal splint. I don’t need references to back that up. Each practitioner has a working hypothesis in diagnosing and treating any disorder. I have shared mine for the diagnosis of muscle pain as it relates to the occlusion, with the readers of the Journal. It is mine and while I have been influenced by many, I am responsible for the whole. I am willing to let the profession decide whether these diagnostic tests have any value. J HART LONG, JR., DDS 320 HARVEY AVE. DAYTONA BEACH, FL 32118
To THE EDITOR: I am writing in regard to the article by Dr. Assif, published in January 1991, entitled “Restoring teeth following crown lengthening procedure” (1991;65:62-4). The Table I values of average crown height, root length, and root-to-crown ratio are calculated, as the authors duly acknowledged, from the cementoenamel junction (CEJ) as the reference point. In Table II, the expected values of root-to-crown ratio following extrusion have been calculated from alveolar crest as the reference point. Alveolar
391
READERS’
bone crest has been defined on page 63 as being ideally 1 mm apical to the CEJ. The authors appear to have been comparing root-to-crown ratio from Table I to root-tocrown ratio from Table II, to find a basis for calculating the restorability of a fractured tooth before extrusion. These two tables cannot be used for comparison for the reasons described here. In the example of the maxillary canine, the root-to-crown ratio would not be 1.7, as from Table I, but 1.4, if it is calculated from the alveolar bone crest. The authors based their decision on restorability of fractured teeth on “Thus the distance from the alveolar crest to the coronal border of sound tooth structure should be a minimum of 4 mm (reference:Johnson GK, Sivers JE, Forced eruption in crown lengthening procedures. J PROSTHET DENT, 1986;56:424-7). In this article, Johnsonand Silvers state that “Thus the distance from the alveolar crest to the coronal extent of soundtooth structure shouldbe a minimum of 3 to 4 mm.” It appearsthat the calculations are questionable. E. V. BASS, MDSc SPECIALIST PROSTHODONTIST UNITED DENTAL HOSPITAL OF SYDNEY AUSTRALIA
Repb To THE EDITOR:
In responseto the letter by Dr. E. V. Bassin regard to my article entitled “Restoring teeth following crownlengthening procedure” (Jan 1991;65:62-4),I wish to make the following comments. Dr. Bass states that neither the calculations nor the quotation of referencesareof great value to dimensions.To deal with the calculations first, Table I givesaverage anatomic values in a healthy normal dentition. The columns stating values of crown height and root length explain the
392
ROUND
TABLE
way of calculating root/crown ratio, which is the basisof Table II. Table II independently demonstratesthe possibilities for restoring mutilated teeth, basedon two assumptions: (1) the gingivo-occlusal dimension of the crown remainsunchanged following extrusion, becausethe bone crest remainsuntouched, and (2) the root length is reduced by the amount of extrusion neededto create 4 mm of sound tooth structure coronal to the alveolar crest. The reasonfor 4 mm is that in order not to impinge on the epithelial attachment, which is the coronal component of the biological width, the crown marginsshould belocated 2 mm above the bony crest, which is 1 mm occlusalto the original location of the CEJ. The alveolar crest wasusedasa landmark becauseit is a radiographically identifiable referencepoint in contrast to the CEJ and especially in prepared and/or mutilated teeth or roots. Therefore, we were surprised that Dr. Bassdoesnot regard our quotations as being of value. The sentence precedingthe onequoted from the article in the secondlast paragraphof his letter statesthat “An additional 1 to 2 mm of soundtooth structure is necessarycoronal to the epitheha1attachment to allow placement of the restorative margin.” If we require 2 mm of bracing, it follows that the distance from alveolar crest to the coronal extent of sound tooth structure shouldbe aminimum of 4 mm (If only 1mm bracing is consideredsufficient, then indeed only 3 mm of sound coronal tooth structure is necessary). We regret the typographical error in reference 7, which should read Johnson GK, not Thomson GK. DAVID
ASSIF, DMD
SECTION OF ORAL REHABILITATION THE MAURICE AND GABRIELA GOLDSCHLEGER SCHOOL OF DENTAL MEDICINE TEL AVIV UNIVERSITY TEL AVIV ISRAEL
AUGUST
1992
VOLUME
68
NUMBER
2
lateral pterygoid muscle palpation.16 The statement about the physiological status within the muscle, that is, level of oxygenation, is pure speculation with no measure of this parameter. 3. Last, the clinical treatment of temporomandibular disorder patients with an irreversible procedure such as “(1) reshaping the teeth so that there are no longer any noxious contacts” in the OccEusal Therapy treatment modality section of the article, has been discouraged by the literature. The American Dental Association sponsored two major symposiums in 1978 and a follow-up in 1988; the published consensus findings of both concluded that this procedure would be contraindicated in a patient with masticatory muscle pain.s-1° Unfortunately, this article will be used by some clinicians to justify irreversible procedures on their patients, based on the author’s proposed objective tests, that is, “muscle palpation” and “the stress test with a leaf gauge.” The use of the leaf gauge has been accepted and utilized in clinical dentistry as an adjunct to obtaining a centric relation interocclusal record. However, Donegan et a1.17 have cast some doubt on the effect of the leaf gauge in altering masticatory muscle activity; furthermore, this device has not undergone adequate testing in controlled experiments to substantiate its use as a diagnostic aide. THE JOURNAL OF PROSTHETIC DENTISTRY readership should be aware that Dr. Long’s article is simply an opinion of the author and, at best, poorly supported by the scientific literature. JOHN W. STOCKSTILL, DDS, MS JOHN F. BOWLEY, DDS, MS ADULT RESTORATIVE DENTISTRY UNIVERSITY OF NEBRASKA MEDICAL COLLEGE OF DENTISTRY 40~~ AND HOLIPREGE LINCOLN, NE 68583-0740
CENTER
REFERENCES 1. MacDonald
2.
3.
4. 5.
6.
I. 8.
9.
10.
11. 12.
THE
JW, Hannam AG. Relationship between occlusal contacts and jaw-closing muscle activity during tooth clenching: Part I. J PROSTHET DENT 1984;52:718-29. MacDonald JW, Hannam AG. Relationship between occlusal contacts and jaw-closing muscle activity during tooth clenching: Part II. J PROSTHET DENT 1984;52:862-7. Wood WW, Takada K, Hannam AG. The electromyographic activity of the inferior part of the human lateral pterygoid muscle during clenching and chewing. Arch Oral Biol 1986;31:245-53. Wood WW. Medial pterygoid muscle activity during chewing and clenching. J PRO~THET DENT 1986;55:615-21. Gibbs CH, Mahan PE, Wilkinson TM, Mauderli A. EMG activity of the superior belly of the lateral pterygoid muscle in relation to other jaw muscles. J PROSTHET DENT 1984;51:691-702. Lund JP, Widmer CC. An evaluation of the use of surface electromyography in the diagnosis, documentation, and treatment of dental patients. 3 Craniomandib Disord 1989$125-37. Berry DC. Occlusion: fact and fallacy. J Craniomandib Pratt 1986;4:5464. Griffiths RH. Report of the president’s conference on the examination, diagnosis, and management of temporomandibular disorders. J Am Dent Assoc 1983;106:75-7. Ohrbach R, Gross A. Summary of the workshop on temporomandibular disorder sponsored by the American Dental Association. 3 Periodontal 1989;60:222-4. Laskin D: Greenfield W, Gale E, et al. President’s conference on the examination, diagnosis, and management of temporomandibular disorders. Chicago: American Dental Association, 1982. Johnstone DR, Templeton M. The feasibility of palpating the lateral pterygoid muse1e.J PROSTHETDENT 1980;44:318-23. Dworkin SF, LeResche L, DeRouen T, Van Korff M. Assessing clinical
JOURNAL
OF PROSTHETIC
DENTISTRY
13.
14.
15.
16. 17.
signs of temporomandibular disorders: reliability of clinical examiners. J PROSTHETDENT 1990;63:574-9. Seligman DA, Pullinger AG, Solberg WK. Temporomandibular disorders. Part III: occlusal and articular factors associated with muscle tenderness.J PROSTHETDENT 1988;59:483-9. Droukas B, Lindee C, Carlsson GE. Occlusion and mandibular dysfunction: a clinical study of patients referred for functional disturbances of the masticatory system. J PROSTHET DENT 1985;53:402-6. De Last A, van Steenberghe D, Lesaffre E. Occlusal reIationships and temporomandibular joint dysfunction. Part II: correlations between occlusal and articular parameters and symptoms of TMJ dysfunction by means of stepwise logistic regression. J PROSTHET DENT 1986;55:116-21. Stockstill JW, Gross AJ, McCall WD. Interrater reliability in masticatory muscle palpation. J Craniomandib Disord 1989:X143-6. Donegan SJ, Carr AB, Christensen LV, Ziebert GJ. An electromyographic study of aspects of ‘deprogramming’ of human jaw muscles. J Oral Rehabil 1990;17:509-18.
Repb To THE EDITOR: This is my response to the letter of Dr. John Stockstill and Dr. John Bowley. The last sentence in the letter from Drs. Stockstill and Bowley states that “THE JOURNAL OF PROSTHETIC DENTISTRY readership should be aware that Dr. Long’s article is simply an opinion of the author and, at best, poorly supported by the scientific literature.” I have no reservation in accepting their statement. It is true. I have been treating patients who have occlusal problems for 48 years. During those years the pendulum has swung from occlusal treatment being almost the only treatment for TMJ problems until now it has gone so far in the other direction that many are afraid to make “irreversible changes” in the occlusion at all, as if that isn’t happening during almost every restorative procedure. This article is on diagnosis, not treatment. An article on treatment is waiting publication in the Journal. I have learned that when I get a positive response from the two tests described I can reverse that response by proper occlusal treatment or the insertion of an occlusal splint. I don’t need references to back that up. Each practitioner has a working hypothesis in diagnosing and treating any disorder. I have shared mine for the diagnosis of muscle pain as it relates to the occlusion, with the readers of the Journal. It is mine and while I have been influenced by many, I am responsible for the whole. I am willing to let the profession decide whether these diagnostic tests have any value. J HART LONG, JR., DDS 320 HARVEY AVE. DAYTONA BEACH, FL 32118
To THE EDITOR: I am writing in regard to the article by Dr. Assif, published in January 1991, entitled “Restoring teeth following crown lengthening procedure” (1991;65:62-4). The Table I values of average crown height, root length, and root-to-crown ratio are calculated, as the authors duly acknowledged, from the cementoenamel junction (CEJ) as the reference point. In Table II, the expected values of root-to-crown ratio following extrusion have been calculated from alveolar crest as the reference point. Alveolar
391
READERS’
bone crest has been defined on page 63 as being ideally 1 mm apical to the CEJ. The authors appear to have been comparing root-to-crown ratio from Table I to root-tocrown ratio from Table II, to find a basis for calculating the restorability of a fractured tooth before extrusion. These two tables cannot be used for comparison for the reasons described here. In the example of the maxillary canine, the root-to-crown ratio would not be 1.7, as from Table I, but 1.4, if it is calculated from the alveolar bone crest. The authors based their decision on restorability of fractured teeth on “Thus the distance from the alveolar crest to the coronal border of sound tooth structure should be a minimum of 4 mm (reference:Johnson GK, Sivers JE, Forced eruption in crown lengthening procedures. J PROSTHET DENT, 1986;56:424-7). In this article, Johnsonand Silvers state that “Thus the distance from the alveolar crest to the coronal extent of soundtooth structure shouldbe a minimum of 3 to 4 mm.” It appearsthat the calculations are questionable. E. V. BASS, MDSc SPECIALIST PROSTHODONTIST UNITED DENTAL HOSPITAL OF SYDNEY AUSTRALIA
Repb To THE EDITOR:
In responseto the letter by Dr. E. V. Bassin regard to my article entitled “Restoring teeth following crownlengthening procedure” (Jan 1991;65:62-4),I wish to make the following comments. Dr. Bass states that neither the calculations nor the quotation of referencesareof great value to dimensions.To deal with the calculations first, Table I givesaverage anatomic values in a healthy normal dentition. The columns stating values of crown height and root length explain the
392
ROUND
TABLE
way of calculating root/crown ratio, which is the basisof Table II. Table II independently demonstratesthe possibilities for restoring mutilated teeth, basedon two assumptions: (1) the gingivo-occlusal dimension of the crown remainsunchanged following extrusion, becausethe bone crest remainsuntouched, and (2) the root length is reduced by the amount of extrusion neededto create 4 mm of sound tooth structure coronal to the alveolar crest. The reasonfor 4 mm is that in order not to impinge on the epithelial attachment, which is the coronal component of the biological width, the crown marginsshould belocated 2 mm above the bony crest, which is 1 mm occlusalto the original location of the CEJ. The alveolar crest wasusedasa landmark becauseit is a radiographically identifiable referencepoint in contrast to the CEJ and especially in prepared and/or mutilated teeth or roots. Therefore, we were surprised that Dr. Bassdoesnot regard our quotations as being of value. The sentence precedingthe onequoted from the article in the secondlast paragraphof his letter statesthat “An additional 1 to 2 mm of soundtooth structure is necessarycoronal to the epitheha1attachment to allow placement of the restorative margin.” If we require 2 mm of bracing, it follows that the distance from alveolar crest to the coronal extent of sound tooth structure shouldbe aminimum of 4 mm (If only 1mm bracing is consideredsufficient, then indeed only 3 mm of sound coronal tooth structure is necessary). We regret the typographical error in reference 7, which should read Johnson GK, not Thomson GK. DAVID
ASSIF, DMD
SECTION OF ORAL REHABILITATION THE MAURICE AND GABRIELA GOLDSCHLEGER SCHOOL OF DENTAL MEDICINE TEL AVIV UNIVERSITY TEL AVIV ISRAEL
AUGUST
1992
VOLUME
68
NUMBER
2
