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A question of alloys
JA B A LETTERS TO THE EDITOR
JADA devotes this section to comment by readers on topics of current interest to dentistry. The editor reserves the right to edit all communications to fit available space and requires that all letters be signed. Printed communications do not necessarily reflect the opinion or official policy of the Association. Your participation in this section is invited.
For patients’ best interests □ I have followed with great interest the reports in JADA concerning the proposed efforts of the American Dental Associa tion to educate the public about periodon tal disease. It is my understanding that the purpose of these efforts is not only to educate the public, but also to attempt to increase the “busyness” in dental prac tices. . . . My suggestion is that general dentists should make every effort to become profi cient in periodontal therapy, treat as many cases of periodontal disease as they feel competent to treat, and make referrals only in cases that need specialty care. In this way, the interest of both the public and the professions at large w ill be prop erly served. I have been a general dentist, at least in spirit, all of my professional career and only relatively recently have been in ci vilian clinical practice limited to peri odontics. I review many malpractice cases against general dentists and regret that sometimes periodontists unnecessar ily exploit the general dentists. Periodontists, as do all specialists, exist only to serve the patient and the general d e n tist. As p e rio d o n ta l disease is episodic and there is no well-defined uncontestable point at which a patient may need active therapy or referral to a peri odontist, it is improper for periodontists to tell patients that they should have been referred earlier by the general dentist. Even when the patient may have to lose one or more teeth, there is no one who can say with precision that if the patient had been seen by the periodontist earlier, the tooth or teeth could have been saved. On a 684 ■ JADA, Vol. 109, November 1984
number of occasions, the patients have certain way when statistics show differ sued the referring general dentist when ent results? . . . Perhaps somewhere there they were told by the periodontists that are data showing that going to the dentist they needed surgical therapy. saves teeth; this is what is needed. Periodontists have testified against If prevention is the goal, w hich it general dentists and in support of the pa should be, as it is more ethical than treat tient. The Academy of Periodontology ment, we should ask ourselves if we can has reported in its newsletter (Aug-Sept prevent best via TV presentations. . . . I 1983), with apparent satisfaction, how believe that the greatest preventive divi general dentists were successfully sued dends w o u ld occur am ong s c h o o l for not referring patients to the periodon children. . . . JOHN W. WITTROCK, DDS, M A tists. A ll of these activities by the peri VIRGINIA COMMONWEALTH UNIVERSITY odontists, however infrequent, detract RICHMOND, VA from this specialty. The news item in the academy newsletter appears to laud law suits against general dentists and reflects poorly on an otherwise respectable or A question of alloys ganization. . . . It is my hope that the general dentists, □ I found Dr. Raymond Bertolotti’s arti and especially the American Dental As cle in the June issue, “Selection of alloys sociation, w ill do everything possible to for today’s crown and fixed partial den effectively preserve and expand the rights ture restorations,” to be a good general of the general dentists in the field of peri review of the various alloys available to odontal therapy, and take whatever steps the profession and the state of the are necessary to discourage lawyers and a marketplace today. I must, however, take issue with several minority of periodontists from harassing the general practitioners. This is not only of Dr. Bertolotti’s statements: On page 961, Dr. Bertolotti states that vital for the future of general practice and the dental profession, but it is absolutely the ADA Acceptance seal does not imply essential for the best interests of the the same degree of confidence as the ADA patient— whom— in the last analysis we Certified seal. This may be true of other products, but anyone who has submitted are all committed to serve. S. N. BHASKAR, DDS, MS, PhD a dental alloy to the ADA Acceptance MONTEREY, CA Program would disagree. In my opinion, the requirements of the Acceptance Pro gram do more to ensure safety and effi Proof of prevention cacy than compliance with ADA specifi cation no. 5 or ADA specification no. 14. □ Some of the sources Dr. Chester Doug The need to submit clinical and labora lass and co-authors cite in the article on tory test data outweighs any confidence the need for periodontal services (June) that may be associated with the ADA Cer provide some disturbing facts. For exam tification specifications. On page 965, Dr. Bertolotti states that, ple, data from the National Center for Health Statistics show that at age 55-65 generally, the porcelain-metal bond there are no differences in the number of strength of base metal alloys is satisfac missing teeth between whites and blacks, tory when these alloys contain beryllium, but whites had eight times as many re but questionable when the alloys lack be stored teeth as blacks. At age 74, whites ryllium. I do not know the basis for Dr. had, on the average, only three more teeth Bertolotti’s opinion. For more than 10 than blacks, but whites receive much years, Howmedica has marketed Micromore dental care than blacks. These data Bond N-P2 A llo y , a beryllium-free, certainly do not show that going to the nickel-chrom ium -based, porcelaindentist w ill save teeth. If we are to moti fused-to-metal alloy. Literally, millions of vate the public, then we should have units have been fabricated, using this al some statistics to prove that going to the loy, with demonstrated clinical accep dentist prevents loss of teeth. . .. tance. There is no documented evidence Is it ethical for someone w ith an that suggests a q ue stio nab le bond exclusivity on a product to imply that if a strength for these alloys. Micro-Bond product is purchased, it will perform a N-P2 Alloy (as well as other beryllium-
LETTERS TO THE EDITOR
free, base metal alloys) appears on the ADA Accepted listing. A more important issue, I believe, is the p o te n tia l to x ic ity of b e ry lliu m containing alloys and the increased cor rosion rates associated with the addition of beryllium to Ni-Cr alloys. These factors outweigh any beneficial effects of beryl lium to the dental laboratory; in 1972, Austenal Dental, Inc (formerly Howm edica, Inc) e lim in ate d berylliumcontaining alloys from its product line. RONALD DUDEK AUSTENAL DENTAL, INC CHICAGO
□ Author’s comment; It is true that the clinical and laboratory test data that need
among these “experts” as to what should constitute porcelain-metal compatibility, the committee has not been able to settle on a specification in more than 10 years of meeting. With such a diversity of opin ion, it is not surprising to find at least one alloy on the current Acceptable list that is notoriously poor in porcelain-metal compatibility. At times, the documentation submitted for Acceptance can be awesome. One alloy manufacturer advertises “ documen tation weighing over 6 lb, more than 300 pages long, with 146 illustrations. It took 4 years and it was worth it!” In regard to Mr. Dudek’s statement about beryllium in casting alloys, porce lain bond strength is indeed “question able” with beryllium-free alloys as many form excessive oxide at elevated tempera tures. However, there are exceptions; Mr. Dudek feels that N-P2 is one of these. I have no data to the contrary. However, in terms of castability and yield strength, qualities that are usually enhanced by be ryllium, N-P2 compares unfavorably to most nickel-chromium-beryllium alloys.
tiveness of a product where specifications do not exist. As a result, the council be lieves that the Certification and Accep tance Programs are basically equivalent in that products submitted and evaluated under either program can be considered safe and useful for the dental profession and the consumer. W AYNE T. WOZNIAK, PhD ASSISTANT SECRETARY COUNCIL ON DENTAL MATERIALS, INSTRUMENTS, AND EQUIPMENT
Dental heroes □ On a positive note, I ’d like to share this material from an article in The Irish Times (July). The writer of the newspaper article re ferred to the nonsporting heroes of the Olympic Games in Los Angeles. Accord ing to the writer, “Anyone who has been watching the games on late-night and early-morning TV will agree that the title must go to the dental profession of America and that these are the ‘Fluoride Games.’ “By far the most significant phenome non so far has been the American Victory Smile. The AVS takes place to the martial m usic of the Star-Spangled Banner; healthy young red-blooded Americans solemnly place their right hand to their left breasts and expose, to an estimated two b illio n view ers, th e ir rows of perfectly-polished, uniformly-spaced and brightly gleaming teeth. Unerringly, the producer moves in for a close-up of the dazzling dentistry . . . do not adjust the brightness button.” F. ROBERT WILKIN, DDS LINCOLNWOOD, IL
‘Pizza palatini?’
to be submitted for an ADA Acceptance could outweigh ADA Certification, as the Acceptance guidelines do include the functional requirements discussed on page 960 of my article. However, there is no assurance that such is the case, as there is no standard for Acceptance analogous to that for Certification. As I personally participated in the Acceptance program as an “expert” reviewer, I can state that there is considerable potential for varia tion in the Acceptance criteria attribut able to the knowledge and beliefs of the reviewer. Many members of the ANSI Porcelain-Metal Subcommittee, of which I am a member, have also participated as reviewers. Because of disagreement 686 ■ JADA, Vol. 109, November 1984
In terms of toxicity, perhaps Mr. Dudek would care to compare the toxicity of about 2 weight % beryllium (found in many nickel-chromium-beryllium alloys) with the toxicity of about 7.5% gallium found in N-P2. RAYMOND L. BERTOLOTTI, PhD, DDS UNIVERSITY OF CALIFORNIA SAN FRANCISCO
□ Council’s comment; The Acceptance program of the Council on Dental Mate rials, Instruments, and Equipm ent is based on the submission of adequate clin ical, laboratory, and biologic investiga tions to demonstrate the safety and effec-
□ In regard to the entity you called “pizza palate” (Letters, August), we have seen this for years in the mouths of our pa tients, and have even experienced it in our own. We have named it “pizza palatini” as we think that is a more euphonious term. We suggest this as a better name for the condition. HERBERT RINKOFF, DDS MOUNT KISCO, NY
Member suggestions □ I agree with Dr. Allen H in d in ’s letter (August) “Membership concerns.” Some of the areas that the members would like the ADA to work on include education for the public as well as for the profession, and equality of licensure for members. Yes, licensing through reciprocity or credentialling time has come. RON HALLMARK, DDS MEMPHIS, TN
JADA devotes this section to comment by readers on topics of current interest to dentistry. The editor reserves the right to edit all communications to fit available space and requires that all letters be signed. Printed communications do not necessarily reflect the opinion or official policy of the Association. Your participation in this section is invited.
For patients’ best interests □ I have followed with great interest the reports in JADA concerning the proposed efforts of the American Dental Associa tion to educate the public about periodon tal disease. It is my understanding that the purpose of these efforts is not only to educate the public, but also to attempt to increase the “busyness” in dental prac tices. . . . My suggestion is that general dentists should make every effort to become profi cient in periodontal therapy, treat as many cases of periodontal disease as they feel competent to treat, and make referrals only in cases that need specialty care. In this way, the interest of both the public and the professions at large w ill be prop erly served. I have been a general dentist, at least in spirit, all of my professional career and only relatively recently have been in ci vilian clinical practice limited to peri odontics. I review many malpractice cases against general dentists and regret that sometimes periodontists unnecessar ily exploit the general dentists. Periodontists, as do all specialists, exist only to serve the patient and the general d e n tist. As p e rio d o n ta l disease is episodic and there is no well-defined uncontestable point at which a patient may need active therapy or referral to a peri odontist, it is improper for periodontists to tell patients that they should have been referred earlier by the general dentist. Even when the patient may have to lose one or more teeth, there is no one who can say with precision that if the patient had been seen by the periodontist earlier, the tooth or teeth could have been saved. On a 684 ■ JADA, Vol. 109, November 1984
number of occasions, the patients have certain way when statistics show differ sued the referring general dentist when ent results? . . . Perhaps somewhere there they were told by the periodontists that are data showing that going to the dentist they needed surgical therapy. saves teeth; this is what is needed. Periodontists have testified against If prevention is the goal, w hich it general dentists and in support of the pa should be, as it is more ethical than treat tient. The Academy of Periodontology ment, we should ask ourselves if we can has reported in its newsletter (Aug-Sept prevent best via TV presentations. . . . I 1983), with apparent satisfaction, how believe that the greatest preventive divi general dentists were successfully sued dends w o u ld occur am ong s c h o o l for not referring patients to the periodon children. . . . JOHN W. WITTROCK, DDS, M A tists. A ll of these activities by the peri VIRGINIA COMMONWEALTH UNIVERSITY odontists, however infrequent, detract RICHMOND, VA from this specialty. The news item in the academy newsletter appears to laud law suits against general dentists and reflects poorly on an otherwise respectable or A question of alloys ganization. . . . It is my hope that the general dentists, □ I found Dr. Raymond Bertolotti’s arti and especially the American Dental As cle in the June issue, “Selection of alloys sociation, w ill do everything possible to for today’s crown and fixed partial den effectively preserve and expand the rights ture restorations,” to be a good general of the general dentists in the field of peri review of the various alloys available to odontal therapy, and take whatever steps the profession and the state of the are necessary to discourage lawyers and a marketplace today. I must, however, take issue with several minority of periodontists from harassing the general practitioners. This is not only of Dr. Bertolotti’s statements: On page 961, Dr. Bertolotti states that vital for the future of general practice and the dental profession, but it is absolutely the ADA Acceptance seal does not imply essential for the best interests of the the same degree of confidence as the ADA patient— whom— in the last analysis we Certified seal. This may be true of other products, but anyone who has submitted are all committed to serve. S. N. BHASKAR, DDS, MS, PhD a dental alloy to the ADA Acceptance MONTEREY, CA Program would disagree. In my opinion, the requirements of the Acceptance Pro gram do more to ensure safety and effi Proof of prevention cacy than compliance with ADA specifi cation no. 5 or ADA specification no. 14. □ Some of the sources Dr. Chester Doug The need to submit clinical and labora lass and co-authors cite in the article on tory test data outweighs any confidence the need for periodontal services (June) that may be associated with the ADA Cer provide some disturbing facts. For exam tification specifications. On page 965, Dr. Bertolotti states that, ple, data from the National Center for Health Statistics show that at age 55-65 generally, the porcelain-metal bond there are no differences in the number of strength of base metal alloys is satisfac missing teeth between whites and blacks, tory when these alloys contain beryllium, but whites had eight times as many re but questionable when the alloys lack be stored teeth as blacks. At age 74, whites ryllium. I do not know the basis for Dr. had, on the average, only three more teeth Bertolotti’s opinion. For more than 10 than blacks, but whites receive much years, Howmedica has marketed Micromore dental care than blacks. These data Bond N-P2 A llo y , a beryllium-free, certainly do not show that going to the nickel-chrom ium -based, porcelaindentist w ill save teeth. If we are to moti fused-to-metal alloy. Literally, millions of vate the public, then we should have units have been fabricated, using this al some statistics to prove that going to the loy, with demonstrated clinical accep dentist prevents loss of teeth. . .. tance. There is no documented evidence Is it ethical for someone w ith an that suggests a q ue stio nab le bond exclusivity on a product to imply that if a strength for these alloys. Micro-Bond product is purchased, it will perform a N-P2 Alloy (as well as other beryllium-
LETTERS TO THE EDITOR
free, base metal alloys) appears on the ADA Accepted listing. A more important issue, I believe, is the p o te n tia l to x ic ity of b e ry lliu m containing alloys and the increased cor rosion rates associated with the addition of beryllium to Ni-Cr alloys. These factors outweigh any beneficial effects of beryl lium to the dental laboratory; in 1972, Austenal Dental, Inc (formerly Howm edica, Inc) e lim in ate d berylliumcontaining alloys from its product line. RONALD DUDEK AUSTENAL DENTAL, INC CHICAGO
□ Author’s comment; It is true that the clinical and laboratory test data that need
among these “experts” as to what should constitute porcelain-metal compatibility, the committee has not been able to settle on a specification in more than 10 years of meeting. With such a diversity of opin ion, it is not surprising to find at least one alloy on the current Acceptable list that is notoriously poor in porcelain-metal compatibility. At times, the documentation submitted for Acceptance can be awesome. One alloy manufacturer advertises “ documen tation weighing over 6 lb, more than 300 pages long, with 146 illustrations. It took 4 years and it was worth it!” In regard to Mr. Dudek’s statement about beryllium in casting alloys, porce lain bond strength is indeed “question able” with beryllium-free alloys as many form excessive oxide at elevated tempera tures. However, there are exceptions; Mr. Dudek feels that N-P2 is one of these. I have no data to the contrary. However, in terms of castability and yield strength, qualities that are usually enhanced by be ryllium, N-P2 compares unfavorably to most nickel-chromium-beryllium alloys.
tiveness of a product where specifications do not exist. As a result, the council be lieves that the Certification and Accep tance Programs are basically equivalent in that products submitted and evaluated under either program can be considered safe and useful for the dental profession and the consumer. W AYNE T. WOZNIAK, PhD ASSISTANT SECRETARY COUNCIL ON DENTAL MATERIALS, INSTRUMENTS, AND EQUIPMENT
Dental heroes □ On a positive note, I ’d like to share this material from an article in The Irish Times (July). The writer of the newspaper article re ferred to the nonsporting heroes of the Olympic Games in Los Angeles. Accord ing to the writer, “Anyone who has been watching the games on late-night and early-morning TV will agree that the title must go to the dental profession of America and that these are the ‘Fluoride Games.’ “By far the most significant phenome non so far has been the American Victory Smile. The AVS takes place to the martial m usic of the Star-Spangled Banner; healthy young red-blooded Americans solemnly place their right hand to their left breasts and expose, to an estimated two b illio n view ers, th e ir rows of perfectly-polished, uniformly-spaced and brightly gleaming teeth. Unerringly, the producer moves in for a close-up of the dazzling dentistry . . . do not adjust the brightness button.” F. ROBERT WILKIN, DDS LINCOLNWOOD, IL
‘Pizza palatini?’
to be submitted for an ADA Acceptance could outweigh ADA Certification, as the Acceptance guidelines do include the functional requirements discussed on page 960 of my article. However, there is no assurance that such is the case, as there is no standard for Acceptance analogous to that for Certification. As I personally participated in the Acceptance program as an “expert” reviewer, I can state that there is considerable potential for varia tion in the Acceptance criteria attribut able to the knowledge and beliefs of the reviewer. Many members of the ANSI Porcelain-Metal Subcommittee, of which I am a member, have also participated as reviewers. Because of disagreement 686 ■ JADA, Vol. 109, November 1984
In terms of toxicity, perhaps Mr. Dudek would care to compare the toxicity of about 2 weight % beryllium (found in many nickel-chromium-beryllium alloys) with the toxicity of about 7.5% gallium found in N-P2. RAYMOND L. BERTOLOTTI, PhD, DDS UNIVERSITY OF CALIFORNIA SAN FRANCISCO
□ Council’s comment; The Acceptance program of the Council on Dental Mate rials, Instruments, and Equipm ent is based on the submission of adequate clin ical, laboratory, and biologic investiga tions to demonstrate the safety and effec-
□ In regard to the entity you called “pizza palate” (Letters, August), we have seen this for years in the mouths of our pa tients, and have even experienced it in our own. We have named it “pizza palatini” as we think that is a more euphonious term. We suggest this as a better name for the condition. HERBERT RINKOFF, DDS MOUNT KISCO, NY
Member suggestions □ I agree with Dr. Allen H in d in ’s letter (August) “Membership concerns.” Some of the areas that the members would like the ADA to work on include education for the public as well as for the profession, and equality of licensure for members. Yes, licensing through reciprocity or credentialling time has come. RON HALLMARK, DDS MEMPHIS, TN