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The mainstay of periodontal assessment is clinical probing. Radiographic assessment provides quantitative information on the status of tooth-supporting bone. This article reviews methods to assess periodontal structures, including basic radiograph acquisition, assessment of alveolar crest levels, and typical patterns of bone loss. Computer technology to objectively assess loss of alveolar crest from radiographs is reviewed. Developments in computer-assisted quantitation of alveolar crest height are described. Although probing measurements continue to be viewed as more practical than radiographic measurements, radiographic assessment can be made quantitative and is likely easier and more precise than probing for routine assessment of periodontal disease activity., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Background: The exclusive use of mean measurements in periodontal research might at times be misleading, as changes in different sites in the same individual might nullify each other. The purpose of the present study was to compare disease progression and response to periodontal therapy using both individual site activity with thresholds and mean patient changes., Methods: Seventy-nine (79) subjects with established periodontitis were monitored for 1 year (no treatment [NTx] group); 108 subjects who received scaling, root planing, and quarterly prophylaxis were observed in a similar time interval (treatment [Tx] group). Probing depth (PD), attachment level (AL) and alveolar crestal height (ACH) were measured at baseline and 1 year using pressure-sensitive probes and computer-assisted image analysis of radiographs., Results: Mean reduction in PD (0.50 mm) was observed in the Tx group compared to a small increase (-0.04 mm) in the NTx group (P= 0.0001). Treatment resulted in mean AL gain (0.44 mm) compared to net AL loss (-0.21 mm) in the NTx group (P= 0.0001). Subjects in the Tx group had twice as many sites with AL gain (beyond the threshold) compared to NTx subjects (16.64+/-1.07% versus 8.11+/-0.68%) which was highly significant (P = 0.0001, Student t test). Similarly, although in the opposite direction, percentage of sites with AL loss beyond threshold was 6.21+/-0.47% (Tx group) and 14.02+/-1.15% (NTx group) which was also highly significant (P = 0.0001, Student t test). Change in ACH was minimal for the Tx group (-0.07+/-0.03 mm) while NTx subjects experienced greater bone loss throughout the year (-0.16+/-0.02 mm); percentage of sites with ACH loss was similar for both groups, while the Tx group had 3 times the number of sites with ACH gain (11.76% versus 3.42%), suggesting that the reduction in mean bone loss in the Tx group did not result from a reduction in losing sites, but rather from an increase in gaining sites. The use of both means and binary data seems to supplement the information regarding the nature and mechanism of disease progression and arrest., Conclusions: The characteristics of periodontal disease with its multifactorial patient, local, and site-related etiology support the use of both mean and site-based changes in clinical studies of periodontal disease and treatment.

This review defines terms such as accuracy, validity, and reliability, which are used to describe the quality of methods for taking x-rays and for analyzing digital images. Values for these parameters are described for techniques of taking standardized x-rays such as ear-rod fixation and fixation by use of teeth with a dental impression. In addition, values are given for linear measurements on digitized images and for quantitative image subtraction. Differences are addressed between quantitative subtraction with a reference ramp and relative subtraction using the computer-assisted densitometric image analysis (CADIA) system. The relationship between radiographic bone height and clinical attachment level is also discussed. Finally, present and future use in the periodontal office of linear radiographic measurements on digital images and digital subtraction is discussed.

Longitudinal assessment of risk factors for periodontal disease is necessary to provide evidence that a putative risk factor or risk indicator is a true risk factor. The purpose of the present study was to explore longitudinally a variety of markers as possible periodontal risk factors in subjects with little or no periodontal disease at baseline. 415 subjects with mild or little periodontal disease were examined: medical and dental history; socioeconomic profile, clinical measurements, microbial samples and radiographic assessment of bone height were performed at baseline, and at a follow-up examination 2 to 5 years later. Mean probing pocket depth (PPD) at baseline was 1.99+/-0.37 mm while mean overall change was 0.1 mm which amounts to an annual rate of 0.04 mm. Overall mean clinical attachment level (1.75+/-0.6 mm) at baseline resulted in mean attachment change of 0.28 mm (0.12 mm annually). Alveolar crestal height (ACH) at baseline (mean 2.05+/-0.85 mm) resulting in a mean net loss of 0.1 mm. Approximately 10% of all sites presented for the second visit with attachment loss exceeding the threshold (4.4% annually), while only 2.2% of all sites exhibited attachment gain (0.88% annually). Older individuals exhibited greater mean bone loss but the least amount of attachment loss. Current smokers exhibited greater disease progression compared to non-smokers. Tooth morbidity (0.17 teeth/patient/year) was associated with greater baseline CAL and ACH loss, and an assortment of systemic conditions. Subjects who harbored Bacteroides forsythus (Bf) at baseline had greater loss in ACH; likewise, these subjects experienced greater proportions of losing sites and twice as much tooth mortality compared to Bf-negative patients. Baseline clinical parameters correlated strongly with the outcome, i.e., subjects with deeper mean pocket depth at baseline exhibited greater increase in pocket depth overtime; while subjects with greater attachment loss at baseline exhibited greater attachment loss between the 1st and 2nd visits.

Osteoporosis and periodontitis are diseases which affect a large number of women and men, with incidence increasing with advancing age. Osteopenia is a reduction in bone mass due to an imbalance between bone resorption and formation, favoring resorption, resulting in demineralization and leading to osteoporosis. Osteoporosis is a disease characterized by low bone mass and fragility and a consequent increase in fracture risk. Periodontitis is characterized by inflammation of the supporting tissues of the teeth, resulting in resorption of the alveolar bone as well as loss of the soft tissue attachment to the tooth and is a major cause of tooth loss and edentulousness in adults. The relationship of osteopenia to oral bone loss and periodontal disease has been addressed in a limited number of studies. A review of current knowledge regarding this relationship is presented. Interpretation of the literature is complicated by the variety of methods used to assess osteopenia, oral bone mass, and periodontitis, as well as varying definitions of outcomes of interest. Results of a previously unpublished study are presented which suggest that severity of osteopenia is related to loss of alveolar crestal height and tooth loss in post-menopausal women. The literature on the relationship among these disorders is limited and points to the need for additional studies which thoroughly evaluate the influence of potential confounding factors to further define the relationship between low bone mineral density and periodontal disease in larger populations. Clearer understanding of this relationship may aid health care providers in their efforts to detect and prevent osteoporosis and periodontal disease. Increased dialogue among medical and dental professional will be increasingly important in achieving and maintaining patients' optimal health.

The association between supplementary estrogen intake and periodontal and gingival status in a total of 228 women 50 to 64 years of age was examined. Clinical parameters including visible supragingival plaque, subgingival calculus, probing pocket depth, clinical attachment level, alveolar bone height measurements, and number of remaining teeth were measured. Gingival status was recorded as gingival bleeding after gentle manipulation. Selected periopathogens, socio-economic, demographic, smoking habits, and health care variables were assessed. Gingival bleeding was significantly lower in the estrogen supplement group (n = 57) compared to the control group (n = 171) (P = 0.009); the estrogen group also exhibited significantly lower visible plaque levels (P = 0.030) and fewer Capnocytophaga-ssp. (P = 0.032). Dental care was more frequent (P < 0.001), and education levels were higher (P = 0.022) in the estrogen group. To investigate whether differences among the above parameters contributed to the difference in gingival bleeding, an age-adjusted analysis of covariance (ANCOVA) was used. The final ANCOVA indicated non-significant relationships for all parameters examined except estrogen intake (P = 0.044). Women taking estrogen exhibited lower gingival bleeding than the control group after correcting for these factors. The results indicate that estrogen supplementation is associated with less gingival bleeding in women aged 50 to 64, as compared to an age-matched control group.

Subtraction radiography, a sensitive and accurate technique for identifying alveolar crestal change from standardized pairs of radiographs, is useful in monitoring periodontal therapy. One half of the radiographs were found to be appropriate for subtraction analysis using present technology for taking standardized radiographs. The criterion for usability was identical interpretation of subtraction images made in duplicate from a pair of radiographs. A set of radiographs was analyzed by subtraction radiography as well as by measurement of alveolar bone-crest height. Subtraction radiography was found to be more sensitive in detecting change. Whereas 53% pairs of radiographs showed a change on subtraction radiography, only 14% showed a change in crest height. Comparison of change by subtraction radiography and probing attachment level showed an overall correlation. Since these two measures assess different aspects of the periodontium, perfect correlation was not expected.

No practical methods are presently available for measurement of alveolar bone activity at one instant of time. However, roentgenological methods making measurements at 2 different times can be used to assess alveolar bone activity. The most sensitive, specific and accurate method for this purpose presently in use is 125I absorptiometry. This method has the further advantage of giving the patient minimal radiation exposure. New methodology is under development which obviates the need for fixed geometry and could provide a 3-dimensional image of alveolar bone.

Studies utilizing serial standardized periapical radiographs for measurements of alveolar bone height and for digital subtraction and changes in clinical probing attachment level have suggested that adult periodontitis may exhibit periods of exacerbation and remission at specific sites. The use of such serial examinations for the determination of disease activity must be interpreted with caution since the different methods for the assessment of disease activity have different levels of sensitivity and specificity and because such sequential methods integrate disease activity and do not provide an instantaneous measure of activity. An ideal test for disease activity would approach an instantaneous measure of disease activity and would not integrate activity over time.

PREVIOUS STUDIES have shown that 125I absorptiometry gives an accurate and sensitive measure of alveolar bone mass. The purpose of this study was to determine the relationship between alveolar bone mass determined by 125I absorptiometry and bone density obtained by analysis of standardized intraoral radiographs by the Magiscan System. A defect of increasing size was made at one site of the alveolar bone in a human skull. The amount of bone remaining at each step was calculated using 125I absorptiometry. Standardized radiographs were also taken at each step and the relative density in the area of the defect was determined by the Magiscan System. The Magiscan's System Computer Memory permits analysis of identical areas on a longitudinal series of films of the same alveolar bone location. The results indicate that in estimating amounts of alveolar bone the Magiscan analysis of standardized intraoral radiography is similar in sensitivity and accuracy to 125I absorptiometry.

THE BJORN TECHNIQUE is widely used in periodontal studies as a standardized measure of alveolar bone. Recent studies have demonstrated the feasibility of using 125I absorptiometry to measure bone mass. The purpose of this study was to compare 125I absorptiometry with the Bjorn technique in detecting small sequential losses of alveolary bone. Four periodontal-like defects of incrementally increasing size were produced in alveolar bone in the posterior segment of the maxilla of a human skull. An attempt was made to sequentially reduce the amount of bone in 10% increments until no bone remained, a through and through defect. The bone remaining at each step was measured using 125I absorptiometry. At each site the 125I absorptiometry measurements were made at the same location by fixing the photon source to a prefabricated precision-made occlusal splint. This site was just beneath the crest and midway between the borders of two adjacent teeth. Bone loss was also determined by the Bjorn technique. Standardized intraoral films were taken using a custom-fitted acrylic clutch, and bone measurements were made from the root apex to coronal height of the lamina dura. A comparison of the data indicates that: (1) in early bone loss, less than 30%, the Bjorn technique underestimates the amount of loss, and (2) in advanced bone loss, more than 60% the Bjorn technique overestimates it.