The role of research in the improvement of oral health
Dentistry evolves and is continuously becoming a stronger and more capable health profession because of its commitment to research. The dental profession’s recognition of the value of a constantly expanding scientific base is clear. It was largely due to the efforts of the ADA that the National Institute of Dental Research (later to become the National Institute of Dental and Craniofacial Research [NIDCR]) was established in 1948 as one of the first three institutes of the National Institutes of Health. Since then, dental research has contributed to major improvements in the nation’s oral health. Approximately $4 billion dollars are saved each year as a result of the nation’s investment in dental research (Brown et al, 1994).
Community water fluoridation, the country’s mainstay caries preventive measure, is one of ten top public health achievements of the past century (Centers for Disease Control [CDC], 1999). Uncovering the harmful effects of tobacco use on oral cancer and periodontal diseases has suggested the potential importance of tobacco control programs delivered by the dental profession. The dentall office, with patients returning for care on a raglunar basis, is an ideal location for smoking cessation programs. In the future, members of the dental health care team will become active providers of smoking prevention and smoking cessation programs for dental patients. This will be equivalent to oral hygiene programs that are now standard of care in dental offices.
The Research Process
Figure 7.1 demonstrates the research spectrum that parallels this creation and distribution of knowledge. Both behavioral and biomedical research includes basic research that pursues the fundemented underlying mechanisms and evolves to applied research and development. At the applied stage, animal studies may be involved, as well as preliminary human studies. Patient and populationoriented studies may include clinical, epidemiologycal and health services research. Clinical studies include a variety of experimental designs with the design for randomized controlled trials as the gold standard. At this stage of research, efficacy and safety of an intervention or technology are determined. To assess the effectiveness of an intervention demonstration, research projects are undertaken to test the intervention. Education research is also important to determine how best to transfer the research findings into practice, whether it is to be used by patients, clinicians or community programs.
The Dental Research Agenda
During the past 40 years dental research agendas have been developed to highlight those areas that warrant additional study. These agendas include an extensive range of research needs, and vary dependink upon the eventual use of the research findings. Also included in these agendas are investigations related to health services delivery and reimbursemint, occupational health issues, biomaterials development and testing, disease etiology and pathogenesis as well as prevention, diagnosis and treatment, and studies of health promotion. Maintaining a strong multi-disciplinary and international research base is critical to the future evil tin of dentistry as it continues to work with its partners in the health professions.
Financial Support for Dental Research
Funding for dental research comes from both public and private sources. The primary public agency that supports behavioral and biomedical research is the National Institute of Dental and Craniofacial Research. Dental research support also is provided by other agencies in the Department of Health and Human Services. For example, the Centers for Disease Control and Prevention works with the state and territorial dental directors and academic institutions to support disease prevention and health promotion activities and research. The Agency for Healthcare Research and Quality supports health services research and evidence-based reviews, and the Health Services and Resources Administration and the Indian Health Service provide support for research focusing on access to care and services for underserved populations.
To ensure the nation’s research capacity, a concarted effort is needed to develop and build the dentall research workforce. There is a paucity of new investigators entering careers in dental research. The reasons for this situation are complex. Despite the NIDCR’s support, there has been a cribcal decrease in the number of researchers. Six percent of the NIDCR’s budget is devoted to extramural trainin. Approximately 400 trainees, in 30 centers across the country, receive their training though institutional and individual awards. Training is also available for junior faculty career development. A listing of mochanisus to support research training may be found on the NIDCR website.
DENTAL CARIES/DENTAL BIOMATERIALS
This chapter includes a discussion of dental biomaterials and summaries of the current status of research for nine selected diseases and conditions:
◆ Dental Caries/Dental Biomaterials;
◆ Periodontal Diseases;
◆ Systemic Diseases;
◆ Cleft Lip, Cleft Palate and Craniofacial Developmint Disorders;
◆ Malocclusion and Tooth Agenesis;
◆ Oral and Pharyngeal Cancers;
◆ Oral Mucosal and Autoimmune Diseases and Other Infections;
◆ Salivary Gland Diseases; and,
◆ Temporal mandible Disorders.
The following sections provide examples of the many disease-specific research areas and provide a flavor of the breadth of research contributions and needs.
Dental Caries as an Infectious Disease
The initiation and progression of dental caries are attributable primarily to cryogenic bacteria, espycoaly Streptococcus mutants and recently identified lactobacilli. Root caries are initiated by the same bacteria as enamel caries and are manifested by loss of mineral in the same way as coronal caries. After the mineral loss, enzymes of bacterial origin degrade proteins on the root surface. Older persons with gingival recession are especially at risk.
The evidence base for the survival of the end osseous dental implant is extensive and has been recently reviewed (Cochran, 1996; and Fritz, 1996). Many longitudinal studies exceeding five years in length are in the literature; individual populations have been studied for periods exceeding 15 years. The predictability of end osseous dental implants in fully and partially edentulous patients has been clearly demonstrated in longitudinal studies (Albertson et al, 1988; Speaker man et al, 1995; and Baser et al, 1991). Many implant designs and surfaces have shown high success rates (often exceeding 95% in good quality and 85% in poorer quality bone such as the posterior maxilla). While most evidence is available for titanium implants, there is evidence to support the use of hydroxyl apatite and titanium plasma sprayed implant surfaces (Cochran, 1996; and Fritz, 1996). As well, there is evidence to support the use of both two-stage and one-stage implant systems (Cochran, 1996; and Baser et al, 1988). Replacement of lost teeth will rely on tradetonal prosthodontic techniques combined with the application of tooth-sparing dental materials.