Showing papers in "Journal of Dental Education in 1988"

Bone tissue interface.

Abstract: High resolution microradiography and multiple fluorochrome labeling are definitive histological methods for assessing the mechanism and timing of osseous healing, maturation, and adaptation. Two fundamental types of bone interface have been described for endosseous dental implants: (1) fibro-osseous integration ("pseudo-periodontal ligament") and (2) rigid osseous fixation ("osseointegration"). No definitive bone interface studies with modern physiological methods have been reported for fibro-osseous integration. Rigid osseous fixation has been investigated in cortical bone implantation sites. The initial healing reaction involves predominantly bone modeling at the periosteal and endosteal surfaces, i.e., a woven bone callus fills with lamellae by the process of lamellar compaction. Nonvital osseous interface and adjacent compacta are replaced by bone remodeling (turnover). As assessed with high resolution microradiography, "clinically successful" specimens had less than half of the intraosseous interface in direct contact with bone. Extrapolation from animal data suggests that endosseous implants can be provisionally loaded at about 18 weeks, but full maturation of the interface requires approximately one year.

Biomechanics of oral implants: future research directions.

Abstract: Biomechanical principles are relevant in dental implant design because all implants share a common biomechanical purpose: the restoration of masticatory function. Key problems confronting implant designers are: What are the in vivo loadings that dental implants must support? What factors govern interfacial stress transfer? How do biomechanical factors influence tissue reactions at the interface? Dental implant designers are currently in the position of trying to design implants without complete or accurate data to answer these biomechanical questions. These three questions and suggestions for future research are answered in this paper.

Periodontal considerations of implants and implant associated microbiota

Abstract: The scientific and clinical acceptance of the success of osseointegrated dental implants has been firmly established, but the relationships between clinical observation and periimplant pathogenesis is not well understood. Data and concepts regarding the diagnostic value of traditional periodontal evaluation parameters, such as pocket probing depth, bleeding on probing, attachment loss, gingival and plaque indices, and the amount of attached gingiva are discussed. The microbiologic characterization of plaque associated with various implant systems reveals many similarities and some differences compared to natural teeth. An hypothesis for the "periodontal" etiology of implant failure is proposed. The maintenance of edentulous and partially edentulous patients with implants is discussed.

Relationships among dental functional status, clinical dental measures, and generic health measures.

Abstract: Current measures of dental health status are primarily clinical in nature and rely on clinical and radiographic assessment of the patient9s dental health. Information about a patient9s ability to perform usual activities related to good dental health--for example, chewing, speaking, and smiling--is not routinely collected. This study investigated what measures contribute to dental functional status, how they are related to traditional clinical measures, whether dental factors contribute to other generic measures of health, and the extent to which dental factors contribute to overall quality of life. Regression analyses of interview and clinical data from 159 dental patients show that while periodontal status and the number of dental symptoms do explain some of dental functional status, the clinical measures of decayed, missing, and filled teeth do not. Severity of medical condition is correlated with decayed/missing teeth and periodontal health. Quality of life is explained by medical functional status, perceived medical health, and perceived dental health. The dental functional status index may be useful in clarifying the relationship between dental health and overall health and quality of life measures.

Stress Symptoms among Third-Year Dental Students.

Abstract: The purpose of this study was to document the stress (anxiety and depression) symptoms of third-year dental students using two psychological measures. Eighty-six students in two successive third-year classes were tested with the State-Trait Anxiety Inventory (STAI) and Beck Depression Inventory (BDI) in October, December, and April. For both state and trait anxiety, changes across test administrations indicated significant increases for the 1985 class. For depression, no significant changes were found across either test administration or between classes. Comparisons were made between the reported stress symptoms of third-year and first-year dental students. A stress management program within the dental school environment was recommended.

Dental implant retrieval analyses.

Abstract: The evolution of surgical implant devices has been dependent upon a multidisciplinary coordination between the basic and applied biological and physical sciences. In this regard, engineering failure analyses of retrieved prostheses represent a significant contribution. Dental implant retrieval studies have provided guidance for biomaterials, designs and biomechanical function, specialized surface treatments for controlling tissue responses, and associated surgical, periodontal, and restorative regimes. The recent expansion of design concepts and restorative procedures places a new emphasis on the need for interrelated prospective laboratory, laboratory animal, and human device investigations. Retrospective retrieval analyses continue to provide guidance with regard to key concept development and the formulation of important questions and hypotheses for future investigations.

Older Americans' access to oral health care

Abstract: To determine whether older Americans have difficulty obtaining access to dental care, we studied 7,265 adults nationwide. The objectives of this analysis are to: (1) determine the proportion of older Americans receiving dental services, (2) identify the types of services received, and (3) examine barriers to access to dental care in this population. Almost half of the respondents over the age of 60 reported a dental visit in the past year. This is consistent with the national trend of increasing utilization of dental services by older adults in the United States. However, older respondents reported significantly fewer dental visits in the past year than respondents aged 25-59. The mean time since the respondent9s last dental visit increased with increasing age. Minority elders and those older adults with lower incomes, lower educational achievement, poorer perceived health status, chronic diseases, transportation problems, and those living in rural areas had disproportionately fewer dental visits than more socially advantaged respondents. In multivariate analyses, less education, lower income, increasing age, and poorer self-perceived health status were identified as independent risk factors for not having a dental visit, suggesting that certain subpopulations of older Americans are at risk for not receiving necessary oral health services.

Surgical considerations in implant dentistry.

Abstract: Standardized prospective clinical trials are uncommon in implant dentistry. Aside from the Branemark and staple trials; both restricted to edentulous jaws, and two blade trials in their early and as yet inconclusive stages, most implant studies are retrospective. As such, they lack uniformity in patient selection, methodology, evaluation, and definitions of success and do not yield the information needed for critical clinical decisions. There are data to compare treatments for edentulous jaws, but virtually none for the partially edentulous patient. Decisions, out of necessity, involve retrospection and interpolation. In the absence of a definitive data base, added attention must be paid to patient safety and informed consent. Patient selection, implant selection, site selection, and surgical and prosthetic management--all of which influence implant efficacy and safety--are highlighted. It is the opinion of this author, based upon the benefit/risk information reviewed, that osseointegrated root forms are the implants of choice when adequate bone is available, and that blade implants and subperiosteal implants are indicated when bone space is restricted. Prospective clinical trials must be given the highest priority in planning for implant research.

The scientific basis for dental implant therapy.

Abstract: Dental and oral implantology have rapidly moved into the mainstream of dentistry in the last ten years with a phenomenal growth based on rapidly expanding technology, increasing public interest, and the reporting of sound scientific data. This paper reviews current knowledge about implant tissue reactions and identifies areas where additional scientific inquiry is needed. Bone- and soft-tissue healing around dental implants varies greatly depending upon the form of the implant, biomaterial used, and surgical approach. Controversy exists as to whether a direct bony-biomaterial interface is preferable over a bone-connective tissue-biomaterial interface. Scientific data are required to document whether intervening molecular layers of glycoproteins exist between implant and bone, and what role is played by these structures relative to the implant-bone interface. The adaptation of regenerated gingival epithelium to an implant is critical for the development of a perimucosal seal. Many scientific questions remain unanswered about this seal and its role in maintenance of implant longevity. Controlled clinical trials must be carried out to determine clinical serviceability standards for patients. Resolving these areas of concern and understanding the biological reactions involved will require in-depth scientific inquiry by clinician and scientist alike to make dental implantology a highly acceptable and predictable treatment modality. Even with these controversies and lack of comprehensive comparison studies, dental implantology is an exciting treatment concept that makes considerable demands upon the surgical, prosthetic, periodontal, and restorative skills of today's practitioners, and on their scientific understanding as well.

Biocompatibility--the interaction of biomaterials and host response.

Abstract: Future developments for better biocompatibility of dental implants are possible and are discussed here. On each level of local host response, which is subdivided into four phases, improvements of knowledge in basic mechanisms concerning the interaction of biomaterial and host are necessary. For the development of new biomaterials, the limits for load with foreign ions and particles acting on cellular and extracellular matrix should be determined. An example is given for ZrO2-containing glass ceramics. Biochemistry of soft and hard tissue bonding to biomaterials should be investigated. Biomechanical properties of implants could be adapted to individual needs of patients. New composite materials are candidates for the design of long-term functioning implants.

Future directions in surface preparation of dental implants.

Abstract: Clean, intrinsically high-surface-energy dental implants are both safe and effective, but ambiguity remains with regard to the true surface qualities of many implant materials that have been sterilized and are about to be placed in properly instrumented host sites. Future dental implant requirements should include proper surface preparation and surface quality maintenance of the implants themselves. Recommended directions for research on dental implant materials include greater use of surface analytical techniques to identify, understand, and ultimately control common surface contaminants. Regulatory agencies should require specific reporting of critical surface parameters for all dental implant materials in their final, sterile states, including any changes from desirable initial values. Different implants demand different degrees of interaction with adjacent biological phases, for example, to promote or inhibit bioadhesion, and different surface preparations can assure these results.

The dentist's role in access to dental care by Medicaid recipients

Abstract: This study uses a decision analytic approach to assess the dentist9s role in access to care by Medicaid recipients. The question of whether a private dentist, when given the choice, will schedule a Medicaid or non-Medicaid patient is examined. The model considers factors frequently reported to influence dentist9s decisions over whether to accept Medicaid recipients into their practices. Factors include reimbursement rates, probability of broken appointments, and likelihood of reimbursement. The model permits calculation of the expected benefits in dollars for comparable treatment of Medicaid and non-Medicaid patients. Under a variety of conditions, it is shown that the strategy to schedule a non-Medicaid patient dominates alternative strategies in which Medicaid recipients are scheduled. Policy implications of these results are discussed.

Current implant usage.

Abstract: The types of dental implants in current use are described with comments on the various designs, the materials of which the implants are made, the patient situations for which they are used, and the age range of patients treated. The training background of the various clinicians involved is mentioned and comparisons are made between the United States, Japan and Central Europe. Predictions for the future use of implants are made and areas for future research are indicated, based upon deficiencies in our present knowledge.

Chemoprophylaxis of dental patients with prosthetic joints: a simulation model.

Abstract: A computer simulation model was created to assess the risks and effects of no prophylaxis, oral penicillin, and oral cephalexin regimens for dental patients at risk for late prosthetic joint infection (LPJI). Given the assumptions made, this analysis suggests that there is a very small risk of LPJI (29-68 cases per 10(6) dental visits), which is outweighed by a greater risk of death from a fatal antibiotic reaction. Thus, routine predental antibiotic prophylaxis for all dental patients with prosthetic joints may lead to higher mortality. However, clinical experience suggests that antibiotic prophylaxis may be appropriate in "high risk" patients.

Comparison of Personality Variables and Values among Dental Students, Practitioners, and Faculty.

Abstract: Changes in personality and values in four classes of dental students at the University of Alabama School of Dentistry were reported in a previous paper. The purposes of this study were to determine the permanency of these changes after graduation and to compare the personalities and values of students and graduates to those of the faculty. Data were collected using the Myers-Briggs type indicator and the All-port-Vernon-Lindzey study of values. Analysis of variance was used to determine differences among the three groups. Graduates tended to resemble themselves as students. On nine of the ten variables, the faculty clustered differently from the students, the graduates, or both groups, raising the issue of the extent to which faculty members serve as role models.

Requirements for clinical trials.

Abstract: Significant progress and valuable contributions have been made by pioneers in the field of dental implantology during the past 20 years. The feasibility of clinical application of dental implants for specific prosthodontic conditions has been demonstrated by several reports based upon retrospective data or surveys of clinical experiences. However, there is a lack of reliable scientific information to determine the clinical efficacy of implant-supported prostheses or the physiological merits of the two types of implant-bone interface. Similarly, there are no known studies that have tested the relative efficacy of different implant systems. The claims of success rates for different implants can only be substantiated when controlled, independent studies are made, following research protocols that meet the requirements of clinical trials in terms of delineation of hypothesis, definition of treatment, entry and treatment allocations, exclusions and withdrawals, sample size, and a coordinated plan for the statistical analysis of data and interpretation of results. The study design of the VA Cooperative Study has followed the essential requirements of clinical trials in comparing the efficacies of the two treatment modalities--traditional removable partial dentures versus fixed partial dentures supported by implants.

The effect of knowledge of the desired outcome on dental motor performance.

Abstract: Knowledge of the desired outcome of a series of movements is a critical component of motor performance, since it is used to develop the appropriate motor program and to form a basis for understanding terminal extrinsic feedback and formulating subjective reinforcement. In dentistry, information about the desired outcome is almost always disseminated in a lecture and laboratory manual, and a demonstration often is provided. However, mastery by students usually is not given the importance it deserves. The purpose of this study was to evaluate an instructional strategy designed to increase the students' knowledge of the desired outcome by determining whether such knowledge had an effect on dental motor performance. Two intact groups of first-year dental students were randomly assigned to a control or experimental treatment. The control treatment included conventional written and oral descriptions of criteria and methods for completing the occlusal (n = 93) and mesio-occlusal (n = 99) amalgam preparations. The experimental treatment directed the students' attention to critical features of tooth anatomy, and the preparation and methods for assessing performance. Results indicated statistically significant differences (p less than .05) in favor of the experimental group for both performance and degree of agreement with the instructor's evaluation of the mesio-occlusal amalgam only.

Future directions for research on materials and design of dental implants.

Abstract: Previous reviews underscore the uncertainties in our knowledge of the influence of material characteristics, design-shape, and surface texture on the implant material-tissue interface. Current implant designs are based on intuitive approaches and there are no general principles for prediction of success of implant systems. Data on implant surfaces prepared by customary preparative techniques show that they are highly variable and dependent on processing. The long-term (years) effects of trace element release from implants is little understood because of past errors in analytical techniques and paucity of relevant data. To place the development of future implant systems on a more rational basis, scientific studies are needed (1) to identify and characterize new and modified materials and surfaces, (2) to validate surface characterization procedures and evaluate tissue responses to standardized surfaces, and (3) to measure trace and subtrace element levels in animal and human tissues over time in order to establish normal and pathologic limits.

Ten-year study of strategies for teaching clinical inference in predoctoral orthodontic education.

Abstract: Dealing with the continuum of malocclusions in general practice requires diagnostic skills that, according to the Council on Dental Education guidelines, should include an ability to evaluate the severity of malocclusions and to assess the degree of treatment difficulty. This level of diagnostic skills is predicated upon the ability to make a judgment on the basis of inherently ill-defined and insufficient data or, in other words, upon the ability to use rules and procedures of clinical inference. However, conventional methods of predoctoral orthodontic instruction appear to be unsuitable for transmitting these complex skills to dental students. For ten years, alternative instructional strategies involving guided discovery learning, repetitive practice in application of facts and principles to real-life problems, and eventually a prescriptive diagnostic model were employed at our institution. Both classroom instruction and evaluation were focused on attaining mastery in two narrowly specified domains: "Evaluating the Severity of Malocclusions" and "Assessing the Degree of Treatment Difficulty." The large proportion of items mastered by students and the high percent correct recorded on multiple-choice examinations suggest that these instructional methods may be effective for teaching clinical inference at the predoctoral level of dental education.