Trends in Academic Dentistry and Oral Health Research Funding by Gender.

INTRODUCTION: Dental and oral health researchers compose a small share of the research workforce, and within this group female researchers form a much smaller share than male researchers. Additionally, a majority of full-time faculty appointments at dental schools are held by men, with women making up only 39% of full-time appointments. These factors suggest that there could be disparities between men and women in obtaining research funding. OBJECTIVE: The focus of our study was to determine whether there are gender differences in award funding obtained from the National Institute of Dental and Craniofacial Research or the National Institutes of Health (NIH). METHODS: NIH administrative data were analyzed by focusing on Research Project Grants (RPGs), the primary and most commonly used mechanism to support investigator-initiated research projects. Analyses involved 1 or 2 of the following variables: number of unique applicants or awardees, fiscal years 2007 to 2016, average age of unique applicants, awardee's degrees, awardee's age at first R01, and award rates. RESULTS: About two-thirds of RPG applicants and awardees were men. Although there were significantly more male applicants and awardees, there was no significant difference in award rate by gender, and there was no significant award rate variation through time or by degrees. The average ages of RPG applicants were similar for genders for all degrees, except that male dentists and PhD-dentists applying to the National Institute of Dental and Craniofacial Research were older and male MDs and PhD-dentists from dental schools applying to the NIH were older. CONCLUSIONS: This study demonstrated that men in the dental/oral health workforce submit more applications and receive more NIH awards than do women; however, there was no difference in award rates between women and men and no difference in ages by gender at which the first R01 awards are received. KNOWLEDGE TRANSFER STATEMENT: Analyses of the implications of this study by the academic dentistry and oral health community could lead to establishing opportunities to expand the representation of women in dental and oral health research. Increasing the number of applications submitted by women may help achieve an equitable balance of grantees in the workforce.

CT for pediatric, acute, minor head trauma: clinician conformity to published guidelines.

BACKGROUND AND PURPOSE: In 2001, pediatric radiologists participating in a panel discussion on CT dose reduction suggested that approximately 30% of head CT examinations were performed unnecessarily. With increasing concern regarding radiation exposure to children and imaging costs, this claim warrants objective study. The purpose of this study was to test the null hypothesis that 30% of head CT studies for clinical evaluation of children with acute, minor head trauma do not follow established clinical guidelines. MATERIALS AND METHODS: Retrospective review of 182 consecutive patients with acute, minor head trauma from February 2009 to January 2010 at a tertiary care children's hospital emergency department was performed, and clinician adherence to published clinical guidelines for children younger than 2 years and children 2-20 years of age was determined. The binomial test was used for a null hypothesis of 30% unnecessary examinations against the actual percentage of head CTs deemed unnecessary on the basis of established guidelines. Statistical testing was performed for children younger than 2 years and 2-20 years of age. RESULTS: For children younger than 2 years of age, 2 of 78 (2.6%; 95% CI, 0.5%-8.3%) and, for children 2-20 years of age, 12 of 104 (11.5%; CI, 6.4%-18.7%) did not conform to established guidelines. These percentages were significantly less than the hypothesized value of 30% (P < .001). CONCLUSIONS: Clinician conformity to published guidelines for use of head CT in acute, minor head trauma is better than suggested by a 2001 informal poll of pediatric radiologists.

Differential diagnosis of an unusual shoulder articular lesion in an ancient domestic dog (Canis lupus familiaris L., 1758).

A proximal humeral articular surface from an ancient domestic dog deliberate burial was examined during survey of small mammal bones from a prehistoric early Late Woodland archeological site. An unusual lesion on the caudolateral articular surface prompted micro-computed tomography to define detailed structure. Results indicate cortical or immature woven bone arising subchondrally, replacing normal trabeculae, extending through a breach in the cortical surface, and having sharp transition with surrounding normal bone. Organized bone within the lesion indicates that the dog lived for months-to-years following insult. Differential diagnoses initially included: sharp penetrating trauma; intrinsic or extrinsic blunt fracturing force; osteochondrosis or complication of an osteochondral lesion; unusual osteoarthritis; and neoplasia. Computed tomography ruled out normal or unusual osteoarthritis, and neoplasia. The nature and small size of the lesion, relatively small size of the dog, and lack of evidence for complicating infection, suggest against sharp penetrating trauma as a sole cause. The most plausible differential diagnoses include: uncommon fracture-producing force in a companion animal, and blunt intrinsic or extrinsic force causing fracture at a weak point, such as an early osteochondral lesion, that was obliterated by healing. Combined gross examination, micro-computed tomography, and archeological-anthropological influences facilitated refinement of differential diagnosis.

Calcium and vitamin D use among adults in periodontal disease maintenance programmes.

OBJECTIVES: To determine the level of calcium and vitamin D oral supplementation in patients in periodontal disease maintenance programmes. DESIGN: Convenience survey. SETTING: St. Louis Metropolitan region. SUBJECTS AND METHODS: Patients (n = 228) in two university-based, periodontal disease maintenance programmes. MAIN OUTCOME MEASURES: Reported amounts of oral calcium and vitamin D supplementation were tested for differences based on gender and race. RESULTS: The last published recommended daily intakes from the United States (US) Food and Nutrition Board (FNB) for adults >50 years of age are 1,200 mg calcium and 400 IU vitamin D (or 600 IU if over 70). The mean age of the 228 patients (125 females and 103 males) was 63.6 +/- 11.0 years (standard deviation). Of the 228 patients surveyed: (1) 204 (89%) were >50 years of age and of these, only 15 (7%) met the US FNB's recommended intakes of calcium and vitamin D from supplementation; (2) 138 (66%) reported that they took no oral supplementation, with significantly more males (n = 82) than females (n = 56) not taking supplementation (p = 0.03); (3) 88 (39%) took calcium supplementation, with females (947 +/- 511 mg/day) taking significantly (p <0.001) more than males (632 +/- 907 mg/day); and (4) 66 (29%) took vitamin D supplementation, with females(420 +/- 227 IU/day) taking approximately the same amount as males (443 +/- 317 IU/day, p >0.05). The amounts of oral supplementation did not vary with race (p >0.05). CONCLUSION: The use of calcium and vitamin D supplementation has been promoted for years, yet the numbers of adults taking supplements remains low and the level of supplementation varies greatly. Knowledge of the benefits of supplementation needs to be better disseminated and research needs to be conducted to determine optimal levels of calcium and vitamin D supplementation.

A precise receptor-positioning device for subtraction radiography, based on cross-arch stabilization.

OBJECTIVES: To devise and test for reproducibility a new patient-beam alignment device for subtraction radiography. METHODS: A rigid, cross-arch bar was used with bite-registration material. A modified Rinn XCP rod and ring were firmly attached to the bar and were placed in contact with the X-ray cone. The receptor was held by a slot in the bar. Duplicate sets (n=8 pairs) of digital radiographs were made with a modified, calibrated DenOptix photostimulable phosphor system. Image pairs were registered and compared for geometrical and intensity errors by means of quantitative subtraction radiography. The reproducibility of patient-beam alignment for each pair was determined by measuring spatial errors at alveolar crest edges and by comparing magnifications. Intensity errors measured at two predetermined regions of alveolar bone were used to estimate corresponding bone-mass errors. RESULTS: Misalignment at the alveolar crest was generally <1 pixel (0.085 mm), and everywhere < or =0.25 mm. The magnification was constant within a relative standard deviation of 0.13% (n=8). Trabecular features were generally invisible or barely visible in subtraction images. The standard deviation of intensity errors was 1.07% (n=16). This corresponds to a change in bone mass of approximately 2% or less. CONCLUSION: The device has potential for clinical population studies in which the goal is to detect small changes in bone mass and alveolar-crest height. It is convenient to use and comfortable for patients. Because of the cross-arch design, patient-beam alignment is expected to be relatively insensitive to bite-registration errors, tooth movement, and tooth loss.

An overview of radiographic film holders.

OBJECTIVES: To provide an overview of radiographic film holders, from their inception in the early 1900s to present day. METHODS: A Medline literature search was conducted for dental studies that used keywords that pertain to radiographic film holders. Hand searches of the bibliographies were also conducted. Sixty articles (dating from 1896 to 1998) that describe new or improved film holders are reviewed here. RESULTS: From the earliest days of dental radiography, dentists attempted to standardize radiographic images and techniques. The focus of researchers in the 1950s to the 1970s was to develop a film holder that would hold the film and allow easy and predictable alignment of the X-ray tube. As research projects became more dependent on dental radiographic measurements, the focus shifted to producing reproducible radiographic images, from which highly repeatable measurements could be made. CONCLUSION: Existing devices have strengths and weaknesses. Readily available devices are adequate for routine clinical use; however, user-friendly and patient-friendly film-holding devices that result in highly reliable and accurate measurements have yet to be introduced.

Precise image-receptor calibration and monitoring of beam quality with a step wedge.

OBJECTIVE: To describe an extended bootstrap calibration procedure that uses a step-wedge absorber and minimal equipment for rapid, accurate calibration of image receptors and simultaneous monitoring of beam quality. METHODS: Multiple radiographs of a step wedge are made at different exposures, with a precision dosimeter as a reference. An iterative least-squares minimization procedure is used to fit the data with a single calibration function. The calibration range can be extended by varying two exposure parameters in addition to stepwedge thickness. Small variations in beam quality and other experimental artifacts can be detected by testing redundant data for self-consistency. As a demonstration, two photostimulable phosphor (PSP) systems were calibrated, one with a well-regulated X-ray source and the other with a poorly regulated source. RESULTS: The first PSP system was calibrated over a range of 3.2 orders of magnitude with a relative standard deviation of the estimate of only 0.36%. The slope of the calibration curve agreed with the nominal, factory-set value within 0.8% (on a logarithmic scale). The second PSP system had a nearly linear response with a relative standard deviation of the estimate of 0.44% over the upper 97% of its range. Both X-ray sources showed easily detectable variations in tube potential. CONCLUSIONS: The new calibration method eliminates many of the sources of error of previous techniques such as inverse-square sensitometry. If a suitably precise X-ray source is available, the relative accuracy is limited only by the precision of the receptor system.

Gray scale sonography of breast masses in adolescent girls.

OBJECTIVE: To assess the sonographic findings of breast masses in adolescents and the usefulness of sonographic patterns for suggesting a specific diagnosis. METHODS: The sonograms and medical records of 57 girls (mean age, 15.4 years) with palpable breast masses were retrospectively reviewed. Three observers reviewed the sonograms for multiple sonographic findings. Surgery or clinical findings established diagnoses. Statistical analysis was done to determine how well sonographic findings alone and in combination agreed with final histologic diagnoses. RESULTS: Diagnoses included cysts (n = 12), abscesses (n = 7), fibroadenomas (n = 36), a lactating adenoma (n = 1), and a phyllodes tumor (n = 1). The sonographic findings varied significantly among lesion types (P < or = .005). CONCLUSIONS: Our experience suggests that virtually all breast masses in a pediatric population are benign and that sonography has the ability to differentiate among cystic, inflammatory, and solid masses.

The effects of different image file formats and image-analysis software programs on dental radiometric digital evaluations.

OBJECTIVES: To determine if variations in radiodensity data are introduced by lossy Joint Photographic Experts Group (JPEG) compression and/or the use of three software programs. METHODS: An occlusal film with an aluminium step wedge was exposed, processed and digitized under standard conditions. Before the image was saved, the coordinates and the gray-scale value for each pixel in a 20 x 20 pixel area near the middle of the thickest step were recorded. These pixel coordinates and gray-scale values served as Truth 1. In addition, a digital simulated-radiographic image with assigned gray-scale values for each pixel was created and served as Truth 2. The digital data for the scanned radiograph and the simulated radiograph were saved as Tagged Image File Format (TIFF) and lossy JPEG files. Each file was opened with three software programs and the gray-scale values of homologous pixels were recorded. For these pixels in each image type, the mean gray-scale values and standard deviations were calculated. The pixel gray-scale values for each homologous pixel were also individually compared. RESULTS: When the TIFF images were opened with the three software programs, one program resulted in gray-scale values that were not concordant with truth. All JPEG images resulted in gray-scale values that were not concordant with truth. CONCLUSIONS: One software program added a column of 0s to data files. Lossy JPEG compression introduced potentially deleterious variations to radiodensity data, and at least two of the software programs performed JPEG image decompression differently.

Comparison of 5 protocols based on their abilities to use data extracted from digitized clinical radiographs to discriminate between patients with gingivitis and periodontitis.

BACKGROUND: This study was undertaken to compare 5 digital analytic protocols for their abilities to extract data from digital clinical radiographs and discriminate between patients with gingivitis and periodontitis. METHODS: Five digital-image analysis protocols were compared for their abilities to discriminate between two groups of 24 patients each. One group was diagnosed with healthy gingiva (or gingivitis) and the second with periodontitis. These groups were previously evaluated in published studies that used fractal and morphologic analyses. Pre-existing clinical radiographs for each patient were digitized and regions of interest (ROIs) were placed on interdental bone in mandibular posterior quadrants. The 5 protocols used were: 1) MGB: a median filtration to remove high-frequency noise, a Gaussian filtration to remove low-frequency noise, binarization of the resulting image, and quantification of the black pixels; 2) MGBS: the same protocol as MGB except for a skeletonization of the binary image and a quantification of the skeleton's pixels; 3) GBS: Gaussian filtration, binarization (thresholding on the mean pixel value) of the resulting image, skeletonization, and quantification of the pixels of the skeleton; 4) NS: normalization, skeletonization, and quantification of the skeleton's pixels; and 5) S: a variation of NS, except normalization was not used. The resulting values for the 2 patient groups were compared with Mann-Whitney U tests and effect likelihood-ratio test. RESULTS: For digitized radiographs, the mean gray-scale value (+/- standard deviation) for gingivitis patients was 183.22 +/- 18.53 and for periodontitis patients 181.26 +/- 17.20. Mann-Whitney U tests resulted in the following P values for these protocols: MGBS <0.01; S <0.01; GBS <0.01; NS <0.01; and MGB <0.83. Effect likelihood-ratio tests indicated that only MGBS and S significantly contributed to models containing the other factors. CONCLUSIONS: Small variations to protocols affected the strength of the discrimination between the gingivitis and periodontitis groups. While there is potential for morphologic analysis to be used to discriminate between patients with gingivitis and periodontitis, a robust technique was not identified.

The clinical value of ferric ammonium citrate: a positive oral contrast agent for T1-weighted MR imaging of the upper abdomen.

This study was undertaken to determine whether ferric ammonium citrate (FAC), a positive magnetic resonance (MR) contrast agent, is of clinical value in demonstrating or excluding pathology of the upper gastrointestinal tract. A retrospective review was performed of pre- and post-FAC studies of MR examinations in 203 patients from phase II and III clinical trials in whom final diagnoses had been established based on the results of biopsy, surgery, or independent imaging procedures. Two independent reviewers made randomized and blinded assessments of the stomach, duodenum, and pancreas. FAC significantly increased the certainty of diagnosis for normal studies of the stomach and duodenum for both readers (P < 0.001) and for abnormal studies of the stomach for one reader (P = 0.004). FAC also significantly increased the certainty of diagnosis for normal pancreas for one reader (P < 0.001). FAC significantly (P < 0.001) increased accuracy and specificity for diagnoses involving the stomach and duodenum for both readers and for one reader for the pancreas. There was significant improvement in sensitivity for gastric diagnoses (P = 0.013) for one reader but not for the duodenum or pancreas. We conclude that FAC is helpful in demonstrating and excluding upper gastrointestinal pathology on MR.

Relationships between radiographic alveolar bone height and probing attachment level: data from healthy post-menopausal women.

OBJECTIVE: To determine the cross-sectional and longitudinal relationships between radiographic alveolar bone height and probing attachment level in a population of healthy postmenopausal women. MATERIALS AND METHODS: The 81 patients in this report were part of a prospective estrogen replacement interventional study. All patients were in good oral health at entry and received annual oral prophylaxis as part of the study. Standard probing measurements were made with a pressure sensitive probe at 6 sites on each tooth. Vertical bitewing radiographs were digitized, and 6 linear measurements corresponding to probing-site measurements were made from the cementoenamel junction to the alveolar crest. These procedures were performed at baseline and at annual intervals for three years. Data were analyzed both by site and by patient. RESULTS: Moderately strong correlations were found between cross-sectional measurements of probing attachment height and radiographic bone height. Correlations were stronger for patient data (r=0.44-0.61) than for site data (r=0.19-0.36). No relationships were found between longitudinal changes in alveolar bone height and attachment level in either the site data (r=-0.10-0.04). or the patient data (r=-0.005-0.10). CONCLUSION: Healthy patients may experience sporadic, temporary changes in attachment level or alveolar bone height which are resolved without one affecting the other.

Sonographic differences in the appearance of acute and chronic full-thickness rotator cuff tears.

This study was undertaken to identify differences in the sonographic appearance of acute and chronic full-thickness rotator cuff tears. The ultrasonograms of 24 patients with an acute rotator cuff tear and 20 with a chronic tear were reviewed for tear size (width), location, and the presence and distribution of fluid. Among these 24 patients, 75% with a midsubstance tear location had an acute tear; 64% of patients with joint or bursal fluid had an acute tear; 80% of patients with a nonvisualized rotator cuff due to a massive tear had a chronic tear; and 73% of patients with no sonographic evidence of bursal or joint fluid had a chronic tear. In conclusion, a midsubstance location and the presence of joint or bursal fluid were more commonly associated with an acute tear. A nonvisualized cuff and the absence of joint and bursal fluid were more commonly observed with a chronic tear.

Alveolar bone height and postcranial bone mineral density: negative effects of cigarette smoking and parity.

BACKGROUND: Our objective was to test the association between cemento-enamel junction, alveolar-crest distance (CEJ-AC, as measured on digitized vertical bite-wing radiographs) and postcranial bone mineral density (BMD) relative to clinical, dietary, and demographic variables. METHODS: Data were collected in a cross-sectional study of 134 postmenopausal women. CEJ-AC distances were determined from digitized vertical bite-wing radiographs. Lumbar spine and proximal femur BMDs were determined from dual-energy x-ray absorptiometric scans. Correlation analysis and Student t tests were used to identify those variables most associated with CEJ-AC distance. The selected variables were modeled with a backward stepwise regression analysis, with CEJ-AC distance as the dependent variable. RESULTS: Parity (number of pregnancies to term), cigarette smoking, and the interaction of lateral spine BMD with cigarette smoking were independent predictors of CEJ-AC distance (P < or =0.05). Statistical models containing these variables accounted for 19% of the variation in CEJ-AC distances. CONCLUSIONS: CEJ-AC distance in postmenopausal women is the result of a complicated interaction of many effects, including but not limited to, parity, cigarette smoking, and skeletal BMD.

Comparison of morphological measurements extracted from digitized dental radiographs with lumbar and femoral bone mineral density measurements in postmenopausal women.

BACKGROUND: We set out to determine whether morphologic measurements extracted from digitized images of bite-wing radiographs correlated with lumbar and femoral bone mineral density (BMD) measurements in 45 postmenopausal women who had no or only mild periodontal disease (no probing depths >5 mm). METHODS: Lumbar spine and femoral BMDs were determined by dual-energy x-ray absorptiometry. Vertical bite-wing radiographs were taken and digitized. Crestal and apical regions of interest (ROIs) were drawn on the digital images of the maxillary and mandibular alveolar bone on the patient's right and left sides. For each patient, a single morphologic measurement was made for each of 8 ROIs. Correlation analysis was performed to determine the strengths of the relationships between the morphologic measurements made at the 8 locations and between these morphologic measurements and BMD measurements. RESULTS: The correlations (r) between the morphologic operator (MO) measurements and lumbar spine and femoral BMDs were weak (mean r = 0.02, range = 0.32 to -0.26) and not statistically significant, with no clear trends discernible. Correlations between MO measurements made at the 8 alveolar sites were also weak (mean r = 0.05, range = 0.35 to -0.38) and not statistically significant. CONCLUSIONS: The MO measurements used in this study were weakly correlated with lumbar spine and femoral BMDs, with no clear trends discernible in this population of postmenopausal women with no or mild periodontal disease.

Dental photostimulable phosphor radiography.

Photostimulable phosphor radiography (PPR), a mature industry in medical imaging, became available in dentistry in 1994. At least three dental PPR systems have been made available commercially since that time. Although dental PPR offers a number of advantages over film-based methods, some aspects of dental PPR need improvement. Further research is needed to more fully compare and contrast this modality with film-based methods.

Anterior cruciate ligament tears: MR imaging-based diagnosis in a pediatric population.

PURPOSE: To evaluate the diagnostic accuracy of primary and secondary magnetic resonance (MR) imaging findings of anterior cruciate ligament (ACL) tears in young patients with immature skeletal systems. MATERIALS AND METHODS: MR images obtained in 43 patients aged 5-16 years who underwent arthroscopy were retrospectively reviewed. Two reviewers evaluated primary findings (abnormal signal intensity, abnormal course as defined by Blumensaat angle, and discontinuity), secondary findings (bone bruise in lateral compartment, anterior tibial displacement, uncovering of posterior horn of lateral meniscus, posterior cruciate ligament line, and posterior cruciate angle), and meniscal and other ligamentous injuries. RESULTS: There were 19 ACL tears and 24 intact ACLs. Overall sensitivity and specificity of MR imaging in detecting ACL tears were 95% and 88%, respectively. Sensitivities of the primary findings were 94% for abnormal Blumensaat angle; 79%, abnormal signal intensity; and 21% discontinuity. The specificity of all primary findings was 88% or greater. The sensitivity and specificity of the secondary findings, respectively, were 68% and 88% for bone bruise; 63% and 92%, anterior tibial displacement; 42% and 96%, uncovered posterior horn of lateral meniscus; 68% and 92%, positive posterior cruciate line; and 74% and 71%, abnormal posterior cruciate angle. Fifteen (79%) patients had meniscal tears, and five (26%) had collateral ligament injuries. CONCLUSION: Primary and secondary findings of ACL tears in young patients have high specificity and are useful for diagnosis.

The effect of region of interest variations on morphologic operations data and gray-level values extracted from digitized dental radiographs.

OBJECTIVE: To determine the correlations among morphologic operations (MO) values and the correlations among gray-level values for regions of interest (ROIs) placed at various locations on digital images of alveolar bone for 45 patients. STUDY DESIGN: As part of a larger study, up to 7 vertical bite-wing radiographs were taken and digitized for each of 45 patients. Sets of 2 rectangular ROIs were placed on the digitized images of interdental alveolar bone at 4 locations for each patient. The ROIs (1 crestal and 1 apical) were placed between second premolars and first molars in all 4 dental quadrants. Gray-level values were measured, and MO analysis was performed on each ROI. Descriptive statistics were calculated and correlations determined. RESULTS: Paired correlations (such as apical vs crestal, left vs right, maxillary apical vs mandibular apical) of MO values were weak (r = 0.01-0.21), but corresponding correlations for gray-level values were relatively strong (r = 0. 60-0.92). CONCLUSION: MO values varied with ROI location considerably more than did gray-level values. Additionally, ROI size and shape apparently affected MO data. Accurate placement and documentation of ROIs appear to be critical considerations in analyses that use MOs.

Computed radiography versus screen-film radiography: detection of pulmonary edema in a rabbit model that simulates neonatal pulmonary infiltrates.

PURPOSE: To determine if computed radiography is equivalent to screen-film radiography in depicting pulmonary edema and to determine if radiation exposure can be reduced with computed radiography while maintaining equivalent diagnostic accuracy for pulmonary edema. MATERIALS AND METHODS: Oleic acid was intravenously injected into three rabbits at each of four doses: 0, 0.02, 0.04, and 0.06 mL/kg. Two hours later, chest computed radiographs and screen-film radiographs were obtained at 60 kVp and 1.1 mAs. Additional computed radiographs were obtained after reducing milliampere seconds or by reducing milliampere seconds and increasing the kilovolt peak, which reduced bone marrow exposure by up to 20%. The presence of pulmonary opacities, "truth," was established by the wet-dry weight ratio and by chest computed tomography (CT). The radiographs were masked and randomized. Four observers rated the images for the presence of parenchymal opacities with a dichotomous score and judged the quality of the radiographs on a scale from 1 (worst) to 6 (best). Cochran Q tests and McNemar tests were used to analyze the differences in paired comparisons. Image quality was evaluated with logistic regression analysis. RESULTS: There was no significant difference between truth and observer ability to detect opacity for either modality or for any exposure (P > .05). There was no significant difference between computed radiography and screen-film radiography for image quality (P > .05). CONCLUSION: Computed radiography is equivalent to screen-film radiography in the detection of pulmonary edema. Radiation exposure reduction of 20% can be achieved without affecting pulmonary edema detection or image quality.

Relationships between longitudinal changes in radiographic alveolar bone height and probing depth measurements: data from postmenopausal women.

BACKGROUND: The relationship between loss of radiographic alveolar bone height and probing attachment loss has been studied by a number of investigators, with mixed results. Recent studies have found weak correlations and have suggested that the relationship between bone loss and attachment loss is complex, perhaps because changes in bone height and attachment level are separated in time. METHODS: The 85 patients in this report were part of a prospective estrogen replacement interventional study. All patients were in good oral health at entry and received annual oral prophylaxis as part of the study. Standard probing measurements were made with a pressure-sensitive probe at 6 sites on each tooth. Vertical bite-wing radiographs were taken of each patient, radiographs were digitized, and 6 linear measurements (corresponding to probing site measurements) were made from the cemento-enamel junction to the alveolar crest. These procedures were performed at baseline and at annual intervals; this study reports results after 2 years. Data were analyzed both by individual site and by averaging identical sites from all measured teeth for each patient. RESULTS: Very weak direct relationships between change in alveolar bone height and change in attachment level were found in both the site data (r2=0.0022; P = 0.189) and the patient average data (r2=0.031; P= 0.104). CONCLUSIONS: The changes in these patients were probably due to systemic changes in bone health rather than to periodontal disease. However, the weak correlations between changes in attachment level and bone height are similar to recent studies of periodontal disease. Our results support suggestions in the literature that the link between changes in attachment and alveolar bone height is complex, perhaps because changes in the 2 tissue types are separated by a considerable time delay.