Radiographic absorptiometry method in measurement of localized alveolar bone density changes

OBJECTIVE: The objective of this study was to measure the accuracy and precision of a radiographic absorptiometry method by using an occlusal density reference wedge in quantification of localized alveolar bone density changes. STUDY DESIGN: Twenty-two volunteer subjects had baseline and follow-up radiographs taken of mandibular premolar-molar regions with an occlusal density reference wedge in both films and added bone chips in the baseline films. The absolute bone equivalent densities were calculated in the areas that contained bone chips from the baseline and follow-up radiographs. The differences in densities described the masses of the added bone chips that were then compared with the true masses by using regression analysis. RESULTS: The correlation between the estimated and true bone-chip masses ranged from R = 0.82 to 0.94, depending on the background bone density. There was an average 22% overestimation of the mass of the bone chips when they were in low-density background, and up to 69% overestimation when in high-density background. The precision error of the method, which was calculated from duplicate bone density measurements of non-changing areas in both films, was 4.5%. CONCLUSIONS: The accuracy of the intraoral radiographic absorptiometry method is low when used for absolute quantification of bone density. However, the precision of the method is good and the correlation is linear, indicating that the method can be used for serial assessment of bone density changes at individual sites.     

Digital image ratio: a new radiographic method for quantifying changes in alveolar bone. Part II: Clinical application

As reported in a previous paper (1) we have developed a new technique, Digital Image Ratio (DIR), which theoretically avoids some of the drawbacks of quantitative digital substraction radiography. DIR allows the direct computation and visualization of bone-mass-ratio changes. This second paper describes the use of DIR analysis to examine 20 sites in 8 patients undergoing regenerative periodontal therapy. Standardized reproducible radiographs of these 20 sites were taken before and 12 months after surgery. Ten experimental sites were treated with bone graft substitutes (natural coral or natural coral+collagen), and 10 control sites by debridement alone. None of the experimental sites had a density ratio below 1, where I indicates no change. The error was ±0.07 (0.93–1.07). The experimental sites showed an 18% mean increase in bone density (1.18), which increased to 23% (1.23) for sites filled with natural coral alone. All the control sites had values close to 1.00 (1.00±0.07) except for 3 sites, which showed a 9–15% loss of bone density. It is thus possible to compare and quantify the changes in experimental and control sites in the same patient using the percentage gain or loss of bone density. This demonstrates that DIR is suitable for clinical applications, and can be used in clinical analysis when bone changes are expected.     

A radiographic method for assessing changes in alveolar bone height following periodontal therapy

Abstract A method is described for obtaining reproducible radiographs of several groups of teeth in the same jaw. The method was applied to assess changes in the alveolar bone height following periodontal treatment. An oral device was designed to permit direction of the central rays of the beam perpendicularly to the alveolar process in different parts of the jaws. The exposures were made at 60 kVp and 10mA, and standardized procedures were used for developing, fixing and rinsing the films. Alterations in the marginal alveolar bone level were determined in a stereocomparator system. The reproducibility of the method was determined. A pilot experiment was performed on 5 patients with periodontal disease. Following conservative treatment, including scaling and root planing, all patients were subjected to periodontal surgery, including alveolar bone denudation. Radiographs of the alveolar bone were obtained before and 2 months after the operation. By measuring in the stereocomparator parallaxes of both control points and points of the alveolar bone crest on paired radiographs, a mean decrease in interproximal alveolar bone height of 0.69 mm was found. Taking into account the small errors which are inherent in the method, this change in bone height could be regarded as a reliable measure of actual loss of bone.     

Radiographic quantification of alveolar bone level changes

The "random burst" theory has recently been proposed as an explanation of the pattern of periodontal disease progression. The theory predicts that the progression of bone loss at individual sites is not dependent upon previous bone loss and age. A longitudinal radiographic study was designed to test this hypothesis, and to describe the changes in bone level over 2 years in a group of 180 subjects (18-68 years of age) who were not under systematic periodontal treatment. The results indicated that 94% of the sites did not show significant changes in the alveolar bone level during the observation period. The mean annual bone loss for the total population was 0.11 mm. By regressing longitudinal bone loss upon age, it was shown that the rate of bone loss increased rapidly between 33 and 56 years of age while a different pattern was shown for the age intervals 18-32 and 57-68 years. Also, the rate of bone loss increased with increasing initial bone loss. This was less evident in the oldest age group. It was concluded that the progression of bone loss in the present material is consistent with a "burst" theory. However, the progression did not occur randomly with regard to previous loss of alveolar bone and time.     

Radiographic quantification of alveolar bone level changes

Abstract. Radiographic bone level changes over 2 years were assessed by 1 absolute and 2 relative techniques in a group of 180 subjects (age 18–68 years, mean 46.7). The absolute tehnique measured the CEJ-AC distance (mm). The Schei and Björn techniques employed rulers which expressed the alveolar bone level as a % of the root and tooth length, respectively. The applicability and readability of the 3 techniques were compared and their interrelationship evaluated. The absolute technique showed significantly better readability than did both the relative methods (p<0.0005). while the Schei technique exhibited the highest ability in detecting the radiographic change in bone level. The correlation between the measurements of bone level change made by the absolute and Schei techniques (r= 0.87) was far better than that between the other techniques (r= 0.56, 0.59).     

Mandibular alveolar bone volume in patients with different vertical facial dimensions

Objective

To evaluate if there is any difference in alveolar bone surface area in patients with high vertical facial dimension (long face), average vertical facial dimension (average face), and low vertical facial dimension (square short face).

Digital image ratio: a new radiographic method for quantifying changes in alveolar bone. Part 1: theory and methodology

A new method, digital image ratio (DIR), has been developed for directly measuring changes in alveolar bone. The image on the computer monitor represents the relative mass change between two radiographs. Fourier filtering is used to reduce noise artefacts. This method is validated through an experiment with a step wedge. DIR needs only a preliminary calibration of the experimental conditions of operation and avoids tedious calibrations for each measurement as in the case of digital image substraction. Low-voltage X-ray techniques are suggested for long-term quantitative studies of patients to minimize irradiation doses.     

Influence of bioactive glass on changes in alveolar process dimensions after exodontia

BACKGROUND: Preservation of the alveolar process after tooth extraction is desirable because it facilitates placement of endosseous implants and minimizes adverse esthetic results associated with fixed partial dentures. The purpose of this study was to evaluate the clinical effectiveness of bioactive glass used as a graft material combined with calcium sulfate used in the form of a mechanical barrier in preserving alveolar ridges after tooth extraction. METHODS: Sixteen patients who required extraction of 2 anterior teeth or bicuspids participated in the study (split mouth design). After tooth extraction and elevation of a buccal full-thickness flap, experimental sockets were filled with bioactive glass, which in turn was covered with a layer of calcium sulfate. Control sites did not receive any graft or calcium sulfate. Titanium pins served as fixed reference points for measurements. No attempt was made to advance the flap to cover the socket areas on control or experimental sites (open socket approach). Reentry surgeries were performed at 6 months. RESULTS: Reentry surgeries showed that experimental sites presented with (1) significantly more internal socket bone fill (6.43 +/- 2.78 mm vs 4.00 +/- 2.33 mm on control sites), (2) less (although not statistically significantly less) resorption of alveolar bone height (0.38 +/- 3.18 mm vs 1.00 +/- 2. 25 mm on control sites), and (3) similar degree of horizontal resorption of the alveolar bony ridge as compared with controls (3. 48 +/- 2.68 mm vs 3.06 +/- 2.41 mm on control sites). CONCLUSIONS: This study suggests that treatment of extraction sockets with a combination of bioactive glass and calcium sulfate is of some benefit in preserving alveolar ridge dimensions after tooth extraction.     

牙槽突裂植骨吸收率的测量分析

目的:应用螺旋CT三维重建比较牙槽突裂植骨术后不同时间骨量的变化及吸收率。方法:选取单侧完全性牙槽突裂患者,应用螺旋CT三维重建患者术前牙槽突裂隙,利用GE AW4.1软件感兴趣区(ROI)体积测量法对其术后1周、3个月、6个月的牙槽部植骨进行体积测量,获得体积变化数据。结果:术后3个月,植入骨量丧失35.74%;术后6个月,植入骨量丧失55.89%,且在牙槽部颊侧形成良好骨桥的前提下,植入骨在空间上仍有不同程度的吸收,在腭侧较少有骨桥形成。结论:牙槽突裂植入骨存在一定吸收,而且随着时间推移,骨量吸收相应增加。     

牙周炎患者拔牙创骨密度变化的测量分析

目的 探讨因牙周炎拔牙后牙槽骨骨密度的变化。方法 采用双能X线吸收法测量不同原因拔牙后牙槽骨骨密度有腰椎椎体骨密度。结果 牙周炎组牙槽骨骨密度变化值低于非牙周炎组；牙周炎患者腰椎椎体骨密度与非牙周炎患者腰椎椎体骨密度无显著性差异。结论 牙周炎患者拔牙后牙槽骨整合速度低于非牙周炎者的愈合速度，这是由于局部炎症的持续作用造成的，全身骨密度状况并不是影响牙周炎的主要因素。     

Nicotine effects on alveolar bone changes induced by occlusal trauma: a histometric study in rats

BACKGROUND: The aim of the present study was to verify nicotine effects on alveolar bone changes induced by occlusal trauma during a periodontitis experimental model in rats. METHODS: Thirty adult male rats were used. The animals were randomly assigned to one of three groups receiving daily intraperitoneal injections: A, nicotine solution (0.44 mg/ml) and occlusal overload; B, saline solution and occlusal overload; or C, saline solution. Rats from groups A and B underwent bilateral amputation of the second and third molar cusps to simulate an occlusal overload. The first molars were then randomly assigned to receive a cotton ligature in the sulcular area, while the contralateral tooth was left unligated. The animals were sacrificed 30 days later. The resected mandibles were processed, and histomorphometric measurements were performed in the alveolar bone adjacent to the furcation area of the first molars. RESULTS: Nicotine enhanced the bone loss induced by occlusal trauma (P<0.001) on the ligated teeth of group A (12.27 +/- 4.4 mm2), when compared to groups B (8.43 +/- 3.51 mm2) and C (4.43 +/- 2.17 mm2). Alveolar bone loss (P<0.01) was also observed in the contralateral teeth of groups A (nicotine + trauma) and B (saline + trauma), when compared to group C (saline only). CONCLUSION: Within the limits of the study, it is concluded that nicotine may influence the alveolar bone changes induced by occlusal trauma by enhancing bone loss.     

The dimensions of the facial alveolar bone at tooth sites with local pathologies: a retrospective cone-beam CT analysis

Clinical Oral Investigations - To assess the impact of various local pathologies on facial alveolar bone dimensions at tooth sites. Cone-beam computed tomography images of 60 patients were...     

Relationship between porotic changes in alveolar bone and spinal osteoporosis

Epidemiological studies have shown that post-menopausal women who do not use an estrogen supplement have fewer teeth than those who do. We hypothesized that changes in the dentition of post-menopausal women might be due to alveolar bone alterations by estrogen deficiency. To clarify this, we analyzed the microstructural alveolar bone changes in ovariectomized monkeys and compared these with their lumbar bone mineral density. The % of baseline bone mineral density showed a significant decrease in the ovariectomized group as compared with the controls. The second-molar interradicular septa in ovariectomized monkeys showed a significantly decreased nodes number, cortices number, and an increased structural model index value. More pores were seen in the ovariectomized group at the top of the septa. This study demonstrated that, in such monkeys, estrogen deficiency led to fragility of the trabecular structure of the molar alveolar bone, and such fragility was inversely correlated with lumbar bone mineral density.     

Color conversion of alveolar bone density changes in digital subtraction images

This study evaluated the influence of image processing of digital subtraction images on inter- and intra-examiner agreement relative to the detection of alveolar bone change on radiographs. 62 sites on digital subtraction images from standardized radiographs from patients requiring periodontal surgery were included in this study. The images were displayed as digital subtraction images, contrast enhanced subtraction images and as color-converted digital subtraction images. The images were projected in random order, analyzed by 4 interpreters and 1 of 8 possible diagnostic decisions was noted for each one of 62 sites. 2 months after the first evaluation, the slides were re-analyzed. 3 different computations (overall agreement, specific agreement and kappa-value) were calculated. The results indicated that image processing of subtraction images using pseudocolor display of the density changes might improve the intra- and inter-examiner agreement.