1974 Report of the Periodontal Diseases Advisory Committee of the National Institute of Dental Research
d. Diagnosis and treatment e. Prevention Total grants In addition: f. Research on herpes simplex virus In fection g. Recurrent aphthous ulcers h. Oral tumors
T H E N A T I O N A L INSTITUTE of Dental Research established the Periodontal Diseases Advisory Committee two years ago as a standing committee to provide the Institute with broad advice in developing programs for the pursuit of periodontal disease research.* The committee held four interesting meetings during F Y 74 at the National Institutes of Health in Bethesda, Maryland. In their committee work, the appointed members of the Periodontal Diseases Advisory Commit tee ( P D A C ) reviewed written material sent to them before meetings by staff, appraised verbal presentations made at the meetings, and participated in discussions to resolve issues or to develop recommendations. In the meetings, the committee provided advice to the N I D R staff on approaches to research and to research man power development for the future and stated opinions on the program balance of N I D R extramural research on periodontal disease. Subject matter orientation was pro vided by invited experts, by N I D R staff scientists, and by committee members themselves.
52,000 52,000 4,054,000
51,000 36,000 490,000
During F Y 1974, the periodontal and soft tissue diseases program awarded research funds of approxi mately $4.7 million for 5 program projects, 58 regular research grants, 18 special dental research awards, and partial support for 1 international symposium. Twentyeight of the awards were made for new research projects. In addition, direct support of $150,000 was provided for 2 new contracts to identify chemotherapeutic agents for dental plaque prevention. For research training, the program awarded $1.26 million for 19 training grants to provide stipends for 87 trainees and $110,000 to support 9 postdoctoral fellows. In addition, 1 career award and 4 career development awards were made at a cost of $117,000. Funding for the new Weinberger program included $323,000 to support 20 postdoctoral fellows on 6 institutional fellowship grants and $205,000 to support 18 individual postdoctoral fellows.
Early in the year formal liaison was established with the National Caries Program Advisory Committee ( N C P A C ) , another N I D R standing advisory committee. A t a joint session, members of the N C P A C and the P D A C agreed that the two committees should exchange information freely and that joint representation at their respective meetings should be encouraged. The two groups also agreed that the committee might specifically cooperate in fostering research programs in certain areas of mutual interest. The distribution of N I D R research grant funds during F Y 1974 for studies of significance to periodontal and other soft tissue diseases, was as follows: a. Studies on the etiology of periodontal disease (ecology, chemistry, metabo lism, adhesion, toxic activity of plaque, etc.) $1,134,000 Miscellaneous etiological factors 180,000 b. Inflammatory response of periodontal tis sues 1,174,000 c. Tissue destruction and healing of perio dontal structures 1,459,000 * Members appointed to the committee were D r . Henry M . Goldman (1975), D r . K i r k Hoermann (1974), D r . Patricia J . Keller (1976), D r . Barnet M . Levy (1975), D r . William D . M c H u g h (1976), M s . Patricia M c L e a n (1974), D r . Ralph Snyderman (1976), and D r . Maynard K . Hine, Chairman (1975), and D r . Anthony A . Rizzo (Executive Secretary) of the N I D R staff. New Members are D r . J . M a x Goodson (1978) and Dr. Genevieve M . Matanosky (1978).
430
The N I D R also supported research activities related to periodontology in its intramural programs and in the 5 university-based institutes and centers at Alabama, Michigan, North Carolina, Pennsylvania, and Seattle. The total funds expended by N I D R for all periodontal disease research activities approached $10 million, which represents about 25% of the total money spent for research by N I D R in F Y 1974. In their discussions, the P D A C members agreed that there was a reasonable distribution of funds in the extramural studies on the etiology and pathogenesis of periodontal disease and complimented the staff for developing a good, well-diversified program. The com mittee did suggest that more emphasis be placed on the biochemical characterization of periodontal plaque, on the relationship of nutrition to periodontal disease, on the early periodontal lesion, and on the development of new criteria for measuring the disease. While the committee was in favor of basic metabolic studies of the periodontal tissues, they believed that there was a disproportionate amount of support going to research on connective tissue metabolism. The P D A C strongly recommended that the immune capabilities of patients with severe periodontal disease should be thoroughly evaluated and that chemical plaque control agents be tested in patients with suscepti bility to disease and also in primates. The committee also believed that more attention should be devoted to the possible role of viruses in the pathogenesis of periodontal disease. Following presentations by outside experts exploring the possibility of preventing plaque by means of con-
Volume 46 Number 7
1974 Report
trolled release of chemical anti-plaque agents into the mouth, the committee encouraged research and develop ment in this promising area. They specifically suggested that a workshop might be held on this subject. Another suggestion offered by the committee was that N I D R initiate a computer search in V A Hospitals of patients with various systemic diseases and relate these to the patients' periodontal status. In the last meeting of the year, the committee devoted considerable attention to discussions on approaches to research manpower development and on the feasibility of expanding research by establishing periodontal disease research centers. It was the committee's judgment that periodontal research had reached the stage of maturation that such research centers would now be an appropriate vehicle by which further advances of significance could be made efficiently. Therefore, the committee was in favor of developing research centers in which investigators with common interests in periodontal disease could work together. In their opinion, these centers should be more comprehensive than program projects, but smaller than
431
dental research institutes. According to the committee, the centers should be funded for 5-year periods and should be subject to competitive renewals. Although their discussions on future manpower and training remain incomplete, it was believed that the committee made a good start in this challenging area. After having de scribed the attributes of an effective clinical researcher in the field of periodontal disease, some members of the committee suggested that an outside group might be invited in to make some technological forecasts. To do this they might use a system such as the D E L P H I method, or the R A N N system, which has been employed by the National Science Foundation to predict man power needs of the future. This report is a slightly modified version of a report given to the Executive Council of the American Academy of Periodontology in October 1974. Maynard K . Hine, D . D . S . Chairman Periodontal Diseases Advisory Committee
Abstracts T H E EFFECTS OF BACTERIAL PLAQUE EXTRACTS ON ORGAN CULTURES OF FETAL RAT MASTICATORY MUCOSA. II. ELECTRON MICROSCOPY Cobb, C . M . J Oral Pathol 3: 35, N o . 1, 1974. The cytotoxicity of bacterial plaque extracts on the ultrastructural level was demonstrated by inoculating organ cultures from fetal rat masticatory mucosa and examining them with electron microscopy. Advanced cytopathologic reactions were characterized in the test group by pronounced tissue and cellular degeneration including disruption of basal lamina, decrease in numbers of cell attachment structures, increased width of intercellular spaces, degeneration of cytoplasmic organelles, and apparent increase in lysosomal activity. Tissue cultures appeared normal until 72 hours after inoculation. Department of Periodontics, School of Dentistry, University of Alabama in Birming ham, University Station, Birmingham, Alabama 35294
A COMPARATIVE STUDY OF THE BUCCAL AND LINGUAL GINGIVAL TISSUES OF THE VERVET MONKEY Fleisch, L . J Periodont Res 9: 92, N o . 2, 1974. Block sections of the mandible and associated soft tissues of eight vervet monkeys were examined histologically to compare the buccal and lingual gingival tissues. The buccal epithelium was found to be thicker and more keratinized with more prominent and deeper pene trating rete pegs. The buccal submucosa had two sets of elastic fibers compared to one found in the lingual submucosa. The buccal elastic fibers consisted of a longitudinal set of thick fibers and a subepithelial plexus of fine fibers. The lingual fibers were found only subepithelially. The different functional demands of resiliency and flexibility of the buccal and lingual epithelia may explain the presence and orientation of the elastic fibers. Dental Research Unit, University of Witwatersrand and the South African Medical Research Council, Jan Smuts Avenue, Johannesburg, Republic of South Africa.
EVIDENCE OF THE ALLOIMMUNOGENIC POTENTIAL OF DONOR PERIODONTAL LIGAMENT Robinson, P . J . and Rowlands, D. T. Am J Pathol 75: 503, June, 1974. Donor teeth were taken from Syrian hamsters which had been subjected to 1000 R total body y irradiation to remove the immuno logic system. The donor teeth were frozen at - 8 0 ° C for a minimum of 24 hours. S k i n graft rejection was used to measure the alloantigenic capacity of the periodontal ligament. The results showed that the donor teeth which had passed through a primary host were able to evoke accelerated rejection of skin grafts (median survival time [ M S T ] = 7.4 days) in a manner similar to tooth allografts in which all components were allogenic ( M S T = 7.5 days) for the host. Center for Oral Health Research, University of Pennsylvania, The Thomas Evans Museum and Dental institute, 4001 Spruce Street, Philadelphia, Pennsylvania 19174
PERIODONTAL JAW MUSCLE REFLEXES IN THE ALBINO RAT Funakoshi, M . and A m a n o , N . J Dent Res 53: 598, May-June, 1974. A n investigation of the activating reflexes on the jaw closing muscles produced by mechanical stimulation to the maxillary incisors was carried out on 27 male and female albino rats using a stereotaxic apparatus and a force displacement transducer or electromagnetic lever. The signal and electromyogram were recorded on an oscilloscope. It was found that either pressing or tapping stimulation on the maxillary incisor activated the masseter muscle mainly. Two reflex pathways were found for this periodontal jaw muscle reflex: (1) passing through the mesencephalic tract nucleus provoked a fast response, and (2) passing through the main sensory nucleus of the trigeminal nerve provoked a slow masseteric response. A n increase in jaw muscle activity, especially in the masseter muscle, can be attributed to mechanoreceptors in the periodontal ligaments. Department of Oral Physiology, Gifu College of Dentistry, Gifu, Japan
d. Diagnosis and treatment e. Prevention Total grants In addition: f. Research on herpes simplex virus In fection g. Recurrent aphthous ulcers h. Oral tumors
T H E N A T I O N A L INSTITUTE of Dental Research established the Periodontal Diseases Advisory Committee two years ago as a standing committee to provide the Institute with broad advice in developing programs for the pursuit of periodontal disease research.* The committee held four interesting meetings during F Y 74 at the National Institutes of Health in Bethesda, Maryland. In their committee work, the appointed members of the Periodontal Diseases Advisory Commit tee ( P D A C ) reviewed written material sent to them before meetings by staff, appraised verbal presentations made at the meetings, and participated in discussions to resolve issues or to develop recommendations. In the meetings, the committee provided advice to the N I D R staff on approaches to research and to research man power development for the future and stated opinions on the program balance of N I D R extramural research on periodontal disease. Subject matter orientation was pro vided by invited experts, by N I D R staff scientists, and by committee members themselves.
52,000 52,000 4,054,000
51,000 36,000 490,000
During F Y 1974, the periodontal and soft tissue diseases program awarded research funds of approxi mately $4.7 million for 5 program projects, 58 regular research grants, 18 special dental research awards, and partial support for 1 international symposium. Twentyeight of the awards were made for new research projects. In addition, direct support of $150,000 was provided for 2 new contracts to identify chemotherapeutic agents for dental plaque prevention. For research training, the program awarded $1.26 million for 19 training grants to provide stipends for 87 trainees and $110,000 to support 9 postdoctoral fellows. In addition, 1 career award and 4 career development awards were made at a cost of $117,000. Funding for the new Weinberger program included $323,000 to support 20 postdoctoral fellows on 6 institutional fellowship grants and $205,000 to support 18 individual postdoctoral fellows.
Early in the year formal liaison was established with the National Caries Program Advisory Committee ( N C P A C ) , another N I D R standing advisory committee. A t a joint session, members of the N C P A C and the P D A C agreed that the two committees should exchange information freely and that joint representation at their respective meetings should be encouraged. The two groups also agreed that the committee might specifically cooperate in fostering research programs in certain areas of mutual interest. The distribution of N I D R research grant funds during F Y 1974 for studies of significance to periodontal and other soft tissue diseases, was as follows: a. Studies on the etiology of periodontal disease (ecology, chemistry, metabo lism, adhesion, toxic activity of plaque, etc.) $1,134,000 Miscellaneous etiological factors 180,000 b. Inflammatory response of periodontal tis sues 1,174,000 c. Tissue destruction and healing of perio dontal structures 1,459,000 * Members appointed to the committee were D r . Henry M . Goldman (1975), D r . K i r k Hoermann (1974), D r . Patricia J . Keller (1976), D r . Barnet M . Levy (1975), D r . William D . M c H u g h (1976), M s . Patricia M c L e a n (1974), D r . Ralph Snyderman (1976), and D r . Maynard K . Hine, Chairman (1975), and D r . Anthony A . Rizzo (Executive Secretary) of the N I D R staff. New Members are D r . J . M a x Goodson (1978) and Dr. Genevieve M . Matanosky (1978).
430
The N I D R also supported research activities related to periodontology in its intramural programs and in the 5 university-based institutes and centers at Alabama, Michigan, North Carolina, Pennsylvania, and Seattle. The total funds expended by N I D R for all periodontal disease research activities approached $10 million, which represents about 25% of the total money spent for research by N I D R in F Y 1974. In their discussions, the P D A C members agreed that there was a reasonable distribution of funds in the extramural studies on the etiology and pathogenesis of periodontal disease and complimented the staff for developing a good, well-diversified program. The com mittee did suggest that more emphasis be placed on the biochemical characterization of periodontal plaque, on the relationship of nutrition to periodontal disease, on the early periodontal lesion, and on the development of new criteria for measuring the disease. While the committee was in favor of basic metabolic studies of the periodontal tissues, they believed that there was a disproportionate amount of support going to research on connective tissue metabolism. The P D A C strongly recommended that the immune capabilities of patients with severe periodontal disease should be thoroughly evaluated and that chemical plaque control agents be tested in patients with suscepti bility to disease and also in primates. The committee also believed that more attention should be devoted to the possible role of viruses in the pathogenesis of periodontal disease. Following presentations by outside experts exploring the possibility of preventing plaque by means of con-
Volume 46 Number 7
1974 Report
trolled release of chemical anti-plaque agents into the mouth, the committee encouraged research and develop ment in this promising area. They specifically suggested that a workshop might be held on this subject. Another suggestion offered by the committee was that N I D R initiate a computer search in V A Hospitals of patients with various systemic diseases and relate these to the patients' periodontal status. In the last meeting of the year, the committee devoted considerable attention to discussions on approaches to research manpower development and on the feasibility of expanding research by establishing periodontal disease research centers. It was the committee's judgment that periodontal research had reached the stage of maturation that such research centers would now be an appropriate vehicle by which further advances of significance could be made efficiently. Therefore, the committee was in favor of developing research centers in which investigators with common interests in periodontal disease could work together. In their opinion, these centers should be more comprehensive than program projects, but smaller than
431
dental research institutes. According to the committee, the centers should be funded for 5-year periods and should be subject to competitive renewals. Although their discussions on future manpower and training remain incomplete, it was believed that the committee made a good start in this challenging area. After having de scribed the attributes of an effective clinical researcher in the field of periodontal disease, some members of the committee suggested that an outside group might be invited in to make some technological forecasts. To do this they might use a system such as the D E L P H I method, or the R A N N system, which has been employed by the National Science Foundation to predict man power needs of the future. This report is a slightly modified version of a report given to the Executive Council of the American Academy of Periodontology in October 1974. Maynard K . Hine, D . D . S . Chairman Periodontal Diseases Advisory Committee
Abstracts T H E EFFECTS OF BACTERIAL PLAQUE EXTRACTS ON ORGAN CULTURES OF FETAL RAT MASTICATORY MUCOSA. II. ELECTRON MICROSCOPY Cobb, C . M . J Oral Pathol 3: 35, N o . 1, 1974. The cytotoxicity of bacterial plaque extracts on the ultrastructural level was demonstrated by inoculating organ cultures from fetal rat masticatory mucosa and examining them with electron microscopy. Advanced cytopathologic reactions were characterized in the test group by pronounced tissue and cellular degeneration including disruption of basal lamina, decrease in numbers of cell attachment structures, increased width of intercellular spaces, degeneration of cytoplasmic organelles, and apparent increase in lysosomal activity. Tissue cultures appeared normal until 72 hours after inoculation. Department of Periodontics, School of Dentistry, University of Alabama in Birming ham, University Station, Birmingham, Alabama 35294
A COMPARATIVE STUDY OF THE BUCCAL AND LINGUAL GINGIVAL TISSUES OF THE VERVET MONKEY Fleisch, L . J Periodont Res 9: 92, N o . 2, 1974. Block sections of the mandible and associated soft tissues of eight vervet monkeys were examined histologically to compare the buccal and lingual gingival tissues. The buccal epithelium was found to be thicker and more keratinized with more prominent and deeper pene trating rete pegs. The buccal submucosa had two sets of elastic fibers compared to one found in the lingual submucosa. The buccal elastic fibers consisted of a longitudinal set of thick fibers and a subepithelial plexus of fine fibers. The lingual fibers were found only subepithelially. The different functional demands of resiliency and flexibility of the buccal and lingual epithelia may explain the presence and orientation of the elastic fibers. Dental Research Unit, University of Witwatersrand and the South African Medical Research Council, Jan Smuts Avenue, Johannesburg, Republic of South Africa.
EVIDENCE OF THE ALLOIMMUNOGENIC POTENTIAL OF DONOR PERIODONTAL LIGAMENT Robinson, P . J . and Rowlands, D. T. Am J Pathol 75: 503, June, 1974. Donor teeth were taken from Syrian hamsters which had been subjected to 1000 R total body y irradiation to remove the immuno logic system. The donor teeth were frozen at - 8 0 ° C for a minimum of 24 hours. S k i n graft rejection was used to measure the alloantigenic capacity of the periodontal ligament. The results showed that the donor teeth which had passed through a primary host were able to evoke accelerated rejection of skin grafts (median survival time [ M S T ] = 7.4 days) in a manner similar to tooth allografts in which all components were allogenic ( M S T = 7.5 days) for the host. Center for Oral Health Research, University of Pennsylvania, The Thomas Evans Museum and Dental institute, 4001 Spruce Street, Philadelphia, Pennsylvania 19174
PERIODONTAL JAW MUSCLE REFLEXES IN THE ALBINO RAT Funakoshi, M . and A m a n o , N . J Dent Res 53: 598, May-June, 1974. A n investigation of the activating reflexes on the jaw closing muscles produced by mechanical stimulation to the maxillary incisors was carried out on 27 male and female albino rats using a stereotaxic apparatus and a force displacement transducer or electromagnetic lever. The signal and electromyogram were recorded on an oscilloscope. It was found that either pressing or tapping stimulation on the maxillary incisor activated the masseter muscle mainly. Two reflex pathways were found for this periodontal jaw muscle reflex: (1) passing through the mesencephalic tract nucleus provoked a fast response, and (2) passing through the main sensory nucleus of the trigeminal nerve provoked a slow masseteric response. A n increase in jaw muscle activity, especially in the masseter muscle, can be attributed to mechanoreceptors in the periodontal ligaments. Department of Oral Physiology, Gifu College of Dentistry, Gifu, Japan
