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Biomedical subjects

M K Jeffcoat

Publications and source records attributed to M K Jeffcoat.

At least 55 records · Page 3Linked to original sources
PubMed1994

A comparison of the diagnostic advantages of panoramic radiography and computed tomography scanning for placement of root form dental implants.

This study evaluated the advantages of computed tomography (CT) in comparison to routine panoramic radiography for dental implant treatment planning. An in vitro validation study was performed to assess the accuracy of CT and panoramic radiography film images for measurement of anatomic structures and distances between anatomic structures. After correcting by a standard 25% magnification on the panoramic images, a significant difference in measurements was found between the CT and panoramic radiography images. Ten subjects requiring implants in compromised ridges were treatment planned with either CT and panoramic radiographs or panoramic radiographs alone. The ideal implant length was determined at surgery with direct digital radiography. The dentists were significantly more confident using CT and panoramic images than panoramic radiographs alone. Implant length treatment planned with panoramic radiography alone underestimated length significantly compared with the implant length determined to be ideal during surgery, whereas treatment planning with CT and panoramic radiography demonstrated no significant difference. The data indicate the CT may be of value in treatment planning for dental implants, especially when gaining maximum length is of critical importance.

Analysis of Variance↗
PubMed1994

Current concepts in periodontal disease testing.

Tests for periodontal disease fall into four categories. The test may identify putative periodontopathic plaque bacteria, the susceptible host, metabolic changes associated with inflammation, tissue damage or death or anatomic changes including periodontal probing and radiographs. The current understanding of tests for periodontal disease is reviewed within a framework for understanding the rationale for such tests.

DNA Probes↗
PubMed1994

Longitudinal evaluation of elastase as a marker for the progression of periodontitis.

To determine whether elastase levels in gingival crevicular fluid (GCF) could serve as a marker for the progression of periodontitis, we monitored GCF elastase and periodontal status in selected sites in 32 periodontally healthy volunteers and 31 periodontitis patients at intervals over a 6-month period. Clinical measurements included plaque index, gingival index, bleeding on probing, suppuration, probing depth, clinical attachment level, and relative attachment level measured with an automated disk probe. GCF elastase, detected by reaction with a fluorescent substrate, was assessed visually against fluorescence standards and quantitatively with a fluorometer. Bone loss was detected by subtraction radiography of standardized vertical bite-wing radiographs at baseline and 6 months. Mean visual elastase scores (VES) and quantitative elastase measurements were significantly higher (P < 0.001) in sites from periodontitis patients than in sites from healthy volunteers. When bone loss was used as the criterion for disease progression, significantly higher (P < 0.001) visual and quantitative GCF elastase levels were found at progressing sites than in nonprogressing sites in the periodontitis patients. The odds ratios (OR) for the event of developing bone loss with positive 4-minute and 8-minute VES tests were 4.2 (P < 0.001) and 7.4 (P < 0.001), respectively. When corrected for the tendency of progressing sites to be clustered within a subpopulation of patients, the OR for developing bone loss with the 4-minute and 8-minute VES tests were 3.1 (P < 0.007) and 4.9 (P < 0.001), respectively. These data indicate that sites with high levels of elastase are at significantly greater risk for progressive bone loss as assessed by digital subtraction radiography.

Adult↗
PubMed1993

Effects of nonsteroidal antiinflammatory drugs on bone loss in chronic inflammatory disease.

Several controlled clinical trials have indicated that nonsteroidal antiinflammatory drugs may slow alveolar bone loss in periodontitis. Demonstration of this efficacy is dependent on the development of accurate, sensitive, and specific quantitative methods for the assessment of bony change, such as digital subtraction radiography. Further studies of such methodologies are required to more fully investigate the effect of nonsteroidal antiinflammatory drugs in rheumatoid arthritis.

Alveolar Bone Loss↗
PubMed1993

Bone loss in the oral cavity.

Bone loss in the oral cavity may occur due to many causes, including infection, systemic or local alterations in the host response, or multifactorial causes. The purpose of this article is to review our present understanding of the major causes of oral bone loss in adults, with special emphasis on two major oral diseases: periodontitis and residual ridge resorption. Periodontitis is characterized by resorption of the alveolar bone as well as loss of the soft tissue attachment to the tooth. Progressive periodontitis will result in continued alveolar bone loss and may result in tooth mobility, abscesses, and ultimately tooth loss. Although the reported prevalence may vary according to the epidemiologic study design, the 1985 National Survey of Oral Health of United States Adults indicated that 94% of female senior citizens examined demonstrated at least one site with at least 2 mm loss of attachment. Resorption of alveolar bone that occurs following tooth extraction is termed residual ridge resorption. In many cases, the denture will loosen because of the inability of the resorbed ridge to stabilize the prosthesis. In the most severe cases, the denture may impinge on the exposed mandibular nerve, resulting in pain or total inability to tolerate the prostheses. Although clear statistics on the prevalence of residual ridge resorption are not available, this boss loss may result in the need for new dentures to replace ill-fitting prostheses.

Adult↗
PubMed1993

Efficacy of meclofenamate sodium (Meclomen) in the treatment of rapidly progressive periodontitis.

This 6-month, double-blind, controlled clinical trial determined the efficacy of the non-steroidal anti-inflammatory drug, meclofenamate sodium (Meclomen), as an adjunct to scaling and root planing in the treatment of rapidly progressive periodontitis (RPP). 22 subjects (7 male, 15 female) aged 36.5 +/- 7.88 years with RPP and disease-active sites as determined by pretreatment bone scan had standardized radiographs at baseline and 6 months, and clinical measurements at baseline, 3 and 6 months. Following full-mouth scaling and root planing, subjects were randomly assigned to either a placebo, 50 or 100 mg meclofenamate sodium bid group. Bone change over the 6-month period as assessed by subtraction radiography was the primary efficacy determinant. Specialized software was used to isolate the lesion from the subtraction image and to measure bone change along the root surface. ANOVA using the subject as the unit of analysis revealed a significant dose response (p < 0.001) with the placebo group having a mean bone loss of 0.42 +/- 0.06 mm and the low and high dose groups having mean bone gains of 0.07 +/- 0.05 and 0.20 +/- 0.07 mm, respectively. These findings indicate that meclofenamate sodium may be a useful adjunct in the treatment of rapidly progressive periodontitis.

Adolescent↗
PubMed1993

Changes in inflammatory mediators in experimental periodontitis in the rhesus monkey.

Ligature-induced periodontitis was monitored for 6 months in eight Macaca mulatta monkeys to examine clinical status, radiographic bone level, and crevicular fluid (CF) levels of prostaglandin E2 (PGE2), thromboxane B2 (TxB2), interleukin-1 beta (IL-1 beta), tumor necrosis factor alpha, and leukotriene B4 (LTB4). A split-mouth design was used, with eight ligated teeth and eight contralateral nonligated teeth which develop soft-chow-promoted (spontaneous) disease. Ligated sites experienced an average attachment loss of 0.94 mm per site and linear bone loss of 0.88 mm per site, with spontaneous-periodontitis sites experiencing approximately half the loss of ligated sites. The CF mediator levels showed increased levels of PGE2 and TxB2 at the ligated sites, as compared with the spontaneous sites, with no significant contralateral differences in the IL-1 beta or LTB4 responses. The concentrations of LTB4 in CF reached an early threefold peak over the baseline level at 1 month. By 2 months there was a statistically significant threefold elevation in CF-PGE2 in the ligated sites and a twofold elevation in the spontaneous sites as compared to the baseline level (P = 0.041 and 0.008, respectively). The monocyte product IL-1 beta increased sharply at 2 months and returned to the baseline level by 6 months at both ligated and nonligated sites. Tumor necrosis factor alpha in CF was below the limit of detection at all sites throughout the experiment (i.e., < 2 ng/ml). The selective elevation of both PGE2 and TxB2 in ligated sites, compared with levels in spontaneous sites, in the presence of similar levels of LTB4 and IL-1 beta provides further evidence that these molecules regulate the magnitude of the tissue-destructive response in progressive periodontitis.

Animals↗
PubMed1993

Digital subtraction radiography for longitudinal assessment of peri-implant bone change: method and validation.

The purpose of this paper is to present a digital subtraction technique for the assessment of peri-implant bone change over time in vivo. Digital subtraction radiography may be used to detect areas of bony change that have occurred between radiographic examinations, and image processing algorithms have been developed which can relate the magnitude of the change on the subtraction image to a reference wedge, thereby allowing calculation of the mass of the lesion. This manuscript will present two algorithms for the assessment of osseous change. The method was validated in monkeys by means of small bony chips placed intra-orally prior to the first radiograph. The chips were removed, a second radiograph taken, and the images subtracted. Each algorithm was used to isolate the lesion and calculate change in bone mass. Overall, there was excellent correlation between the calculated lesion mass (in milligrams) and actual lesion mass (r2 > 0.9). The utility of the method was demonstrated by comparison of the results of subtraction radiography in successful implants and in implants that did not integrate during the healing phase.

Absorptiometry, Photon↗
PubMed1993

Systemic osteoporosis and oral bone loss: evidence shows increased risk factors.

Aging is associated with a loss of bone mass and an increased risk of oral and systemic bone loss. Systemic osteoporosis can result in bone fractures, especially of the spine and hip, with the characteristic spinal curvature and loss of height often seen in osteoporotic postmenopausal women. Loss of teeth and ridge resorption can occur in the mouth.

Alveolar Bone Loss↗
PubMed1993

Application of digital radiography to implantology.

Modern digital radiographic techniques can aid the clinician in planning dental implant selection and placement before and during surgery, a well as in the long term assessment of periimplant bone support. Implant treatment planning can be facilitated using computed tomography on film-based motion tomography. During surgery, direct digital radiography allows the clinician to visualize the relationship of the osteotomy sit to important anatomic structures such as the mandibular nerve. Following placement, digital subtraction radiography permits detection of osseous changes too small to be seen by eye with an accuracy approaching 95%. Such sensitivity and specificity encourages early evaluation and, if necessary, intervention on behalf of the ailing implant.

Dental Implantation↗
PubMed1993

Digital subtraction radiography.

Subtraction radiography offers greater visualization of radiographic changes between a pair of radiographs by subtracting out the unchanging background distractions. Originally, subtraction was achieved by using positive and negative prints in angiography. The advent of digital imaging devices has led to validation of quantitative measurements from digital subtraction images. As well, computer software manipulations have allowed for more flexibility in the clinical application of subtraction imaging. The clinical application of digital subtraction radiography is discussed along with clinical cases.

Humans↗
PubMed1993

Periodontal disease progression.

The progression of periodontitis has been an area of active research during the past year. Prevalence and disease severity studies indicate that severe periodontitis remains a problem of considerable magnitude. The standard for evaluation of periodontitis progression is sequential attachment and bone-level measurements. A vast number of approaches to identify indicators of periodontal disease activity are under development. These include methods to detect bacterial infection or the breakdown of the periodontium. The number of proposed models of periodontal progression has expanded along with the identification of risk factors at the site, subject, and population levels. No model currently under consideration is predictive of future periodontal disease progression.

Age Factors↗
PubMed1992

Quantitative digital subtraction radiography for the assessment of peri-implant bone change.

The purpose of this study was to develop a digital subtraction technique to assess peri-implant bone change. The method uses subtraction radiography to enhance visualization of the area of change that has occurred between radiographic examinations, and superimposes the area of change on the original radiographs. Furthermore, a reference wedge allows calculation of the mass of the lesion. The method was validated using 21 small bony chips placed on 3 different skulls prior to the first radiograph. The chips were removed, a second radiograph taken, and the images subtracted. A morphologic method was used to isolate the lesion and the change in bone mass calculated. Overall, there was excellent correlation between the calculated lesion mass (mg) and actual lesion mass (r2 > 0.90). The utility of the method was demonstrated using a case that experienced implant failure. These data indicate that quantitative digital subtraction radiography may be of value in measuring peri-implant bone change in root form implants.

Alveolar Bone Loss↗
PubMed1992

A semi-automated computer-assisted method for measuring bone loss adjacent to dental implants.

The purpose of this study was to develop a repeatable method for measurement of bone support around root form and blade implants suitable for use in high-quality but unstandardized radiographs. 10 phantoms were fabricated to simulate progressive osseous defects around implants. Radiographs were taken in triplicate and digitized. Specialized software was written which placed a grid of known dimensions over the implant so that the top and the bottom of the grid were at the neck and the base of the implant, respectively. The investigators selected the edge of the bone at each point where the grid intersected the implant and the software automatically detected the implant edge. The software also outlined and displayed the defect on the computer monitor. Measurements were performed 5 times and the standard deviation was taken as a measure of the repeatability of the method. Repeatability for blades and root forms was 0.19 +/- 0.07 mm and 0.08 +/- 0.03 mm, respectively. There was no significant difference in the ability to measure bone loss in the blade versus the root form (p = 0.17, NS). These results indicate that this semi-automated computer-assisted method for measuring bone loss around implants is repeatable and may be of value for clinical trials using either root form or blade implants.

Alveolar Bone Loss↗
PubMed1992

Effects of NSAIDs on beagle crevicular cyclooxygenase metabolites and periodontal bone loss.

This investigation focuses on the changes in the concentrations of cyclooxygenase (CO) products present within the crevicular fluid in naturally-progressing periodontitis in the beagle and the effects of various non-steroidal anti-inflammatory drugs (NSAIDs) on these metabolite levels and disease progression. Six groups of 5-6 beagles with periodontitis were followed for 6 months to determine the pretreatment rate of radiographic bone loss. At baseline, groups of animals were placed on soft chow to promote disease progression. Groups were treated with either placebo, three different formulations of systemic ibuprofen, systemic naproxen or topical flurbiprofen. During the 6-month treatment phase, crevicular fluid (CF) samples and radiographs were taken at regular intervals. Radioimmunoassay of CF samples from untreated animals demonstrated a steady increase in prostaglandin E2 (PGE2) over baseline values. At 1 month, CF-PGE2 levels increased 2-fold over baseline and, by 6 months, had reached a 5- to 6-fold elevation. Crevicular fluid thromboxane B2 (CF-TxB2) levels rapidly reached a 4- to 5-fold peak over baseline at 1 month and subsequently dropped to a 2-fold elevation for the remainder of the study. The rate of bone loss (BLOSS) in untreated animals increased 38% during the 6-month period, as compared to baseline pretreatment BLOSS rates. Overall, there was a significant depression in the CF levels of both PGE2 and TxB2 in all NSAID-treated groups. All NSAID treatments significantly retarded BLOSS, ranging from 21.0-36.9% of the control BLOSS rate. Furthermore, CO activation represents a major regulatory step in bone destruction and may thereby serve as an important site for pharmacological modulation.

Administration, Oral↗
PubMed1992

Digital radiology for implant treatment planning and evaluation.

Digital radiology has provided the clinician with the ability to store and manipulate radiographic information. The purpose of this paper is to present two applications of digital imaging to implantology. The first application is a personal computer-based imaging technique which can be used to plan the placement of endosseous dental implants using three-dimensional computed tomography images obtained with commercial software. The second application uses digital subtraction radiography to assess longitudinal bony change around dental implants.

Dental Implantation↗
PubMed1992

Principles and pitfalls of clinical trials design.

Periodontitis and gingivitis trials can involve many complex experimental designs. The selection of a specific design and the details of the protocol can influence the magnitude of any effect observed, the generalizability of the results, and the clinical significance of the findings. The purpose of this paper is to review selected aspects of clinical trials including the overall clinical experimental design, controls, outcomes, sample size, and patient selection. Particular emphasis will be placed on periodontitis trials.

Clinical Trials as Topic↗