Computer-assisted Densitometric Image Analysis Research Articles

A clinical investigation to assess the regenerative potential of Biostite® (hydroxyapatite, type-I collagen and chondroitin-sulphate) with or without Paroguide® type-I collagen and chondroitin sulphate) membrane in the treatment of periodontal intrabony defects appraised with surgical re-entry and computer-assisted densitometric image analysis.

The traditional treatment procedures which aimed at treating periodontal disease did not result in true periodontal regeneration. Unpredictability about osseous defect fill after periodontal flap surgery has stemmed in the research of a variety of regenerative materials. This randomized clinical trial was conducted to compare regenerative potential of Biostite® bone graft material with and without Paroguide® a bioresorbable membrane in the treatment of periodontal osseous defects. Twenty sites from a total of from ten patients were chosen for the study. Those sites were divided into experimental site A (Biostite®) and experimental site B (Biostite® with Paroguide®) at random. Plaque index and gingival index (GI) were the clinical parameters noted at baseline, 3rd, 6th and 9th months, whereas the probing pocket depth, clinical attachment level and gingival recession were noted at baseline, 6th and 9th months. Radiographic evaluation was made by using computer-assisted densitometric analysis. Intrasurgical measurements were done at baseline and 9 months. Statistical analysis was done using paired t-test and un-paired t-test. Both experimental site A and B showed a significant reduction in plaque and GI. All clinical parameters as well as radiographic image analysis showed highly significant improvement from baseline to 9 months for both sites. Inter-group comparison does not show statistically significant improvement. The results of this study suggested that both Biostite® bone graft and Paroguide® membrane have promised encouraging results in the management of periodontal intrabony defects, however, the groups did differed to each other statistically.

Loss of alveolar bone density in postmenopausal, osteopenic women is associated with circulating levels of gelatinases

To determine whether circulating levels of two matrix metalloproteinases, MMP-2 and MMP-9, are associated with loss of alveolar bone density (ABD) or height (ABH), or with progression of periodontitis (relative clinical attachment level [RCAL]), among postmenopausal women with local and systemic bone loss. This study was planned as part of a 2-year randomized, double-blind, placebo-controlled, clinical trial examining efficacy/safety of subantimicrobial dose doxycycline (20mg bid) in postmenopausal osteopenic women. This study examines whether serum levels of gelatinases are associated with local changes in the periodontium. A sample of 113 women received periodontal maintenance for moderate to advanced chronic periodontitis and consented to analysis of stored serum biomarkers. Posterior vertical bitewings were taken, and serum collected, at baseline, one, and 2years. ABD was determined by computer-assisted densitometric image analysis (CADIA), ABH by the Hausmann etal (1992, J Periodontol 63, 657) method, and RCAL by Florida Probe (every 6months). MMPs were measured densitometrically on gelatin zymograms using denatured type I collagen as substrate and purified MMP-2 (72kDa) and MMP-9 (92kDa) as standards. Evidence of worsening in the periodontium at a tooth site was defined as a change from baseline of, for ABD, at least 14 densitometric units (for subcrestal locations) or 17 units (for crestal locations); of at least 0.4mm for ABH; and of at least 1.5mm for RCAL. Logistic regression models, while accounting for clustering, compared the odds of worsening in ABD, ABH, or RCAL, after 2years of observation, between groups defined by baseline and concurrent levels of serum gelatinases. Changes in ABH and RCAL were not associated with circulating levels of MMP-2 or MMP-9. However, elevated odds of ABD loss over 24months were associated, among smokers, with both baseline and concurrent levels of MMP-9 in the middle and highest tertile, and with concurrent levels of MMP-2 in the middle (but not the highest) tertile. Elevated odds of ABD loss were also associated, among women within 5years of menopause, with baseline levels of MMP-2 in the highest tertile. Among postmenopausal osteopenic women, loss of ABD was associated, in smokers, with elevated circulating levels of MMP-9 and MMP-2. In those within 5years of menopause, ABD loss was associated with elevated circulating levels of MMP-2.

Adjunctive use of modified Yunu-Jian in the non-surgical treatment of male smokers with chronic periodontitis: a randomized double-blind, placebo-controlled clinical trial.

BackgroundYunu-Jian (YJ) is a Chinese medicine (CM) heat purging formula, which is used to reduce wei huo (stomach-heat, SH) and enrich shen yin (kidney-yin, KY). This formula is also commonly used to manage diabetes mellitus and gum/oral inflammation. The activity of YJ can be modified or refined by the addition of other CM herbs and/or minor changes to one of its five key ingredients. The aim of this study was to evaluate the adjunctive use of modified YJ (mYJ) or YJ containing additional osteoblast-stimulating and inflammation-modulating CM herbs in the non-surgical periodontal treatment of smokers with chronic periodontitis in a randomized, double-blind, prospective, placebo-controlled study.MethodsHealthy adult male smokers with untreated chronic periodontitis who showed CM syndrome of SH and KY deficiency (KYD) whilst attending a dental teaching hospital from October to December, 2005, were invited to participate in a randomized double-blind, placebo-controlled clinical trial. The trial itself involved the once-daily oral administration of a placebo or mYJ for 3 months as an adjunct to non-surgical periodontal therapy. Several periodontal parameters, including radiographic alveolar bone density, were measured by computer-assisted densitometric image analysis (CADIA) on selected sites, and CM signs of SH and KYD were followed from their baseline values to various time points up to 12 months or the end of study.ResultsTwenty-five smokers (consumed 25.0 ± 15.3 smoking-pack years, ranged 7.5–80; aged 46.3 ± 6.8 years) with periodontitis and SH and KYD were recruited (Placebo, n = 14; mYJ, n = 11). All of the participants showed good tolerance towards the CM recipe. All of the periodontal parameters had improved after 12-month follow-up, and no statistically significant differences were detected between the control group and test group, except for the higher CADIA values observed compared with the baseline at 12 months for test sites (P = 0.025). 4/3/3 test vs 14/13/13 control participants had persisting SH and KYD at 6, 9 and 12 months (P < 0.001), respectively.ConclusionsThe adjunctive use of mYJ preserved the post-treatment increases in the radiographic alveolar bone density at the study sites and led to an overall improvement in SH and KYD compared with the controls.Trial registration HKU Clinical Trial Register, HKCTR-1848 (www.hkuctr.com/Study/Show/3acbf983831244d29d50b543540bf6e9)Electronic supplementary materialThe online version of this article (doi:10.1186/s13020-016-0111-z) contains supplementary material, which is available to authorized users.

Growing bone assessment made easy at chairside

Various intraoral radiographic techniques have been utilized to study bone changes following periodontal therapy, for example, digital subtraction radiography, computer-assisted densitometric image analysis, computed tomography (CT), and cone bean CT. This short communication provides an insight about a novel yet simple technique which utilizes a user-friendly software (Adobe Photoshop CS3) and provides the clinician a quick, objective economical tool to assess periodontal regeneration (bone fill) radiographically. The use of this software is recommended in any clinical trial, wherein bone is target tissue to be assessed at different time intervals. It can find clinical applications include endodontic periapical cyst therapy, implant, oral and maxillofacial surgery, and orthopedics surgeries. This method is simple, reliable, and reproducible and helps in objective assessment of radiographic changes of the periodontal osseous defects following periodontal therapy.

Radiological analysis of the relationship between occlusal tooth wear and mandibular alveolar bone density and height

The aim of this study was to examine the relationship between occlusal tooth wear and mandibular alveolar bone density (ABD) and alveolar bone height (ABH) using computer-assisted densitometric image analysis (CADIA) program. The study was comprised of 134 mandibular first molar teeth in 90 patients with various degrees of occlusal tooth wear. The degree of tooth wear was classified according to the tooth wear index (TWI). Periodontal examinations were performed on all patients and included plaque index, gingival index, probing depth, and clinical attachment loss measurements. ABD and ABH were measured from intraoral digital periapical radiographs and analyzed using CADIA. No increases in ABD were observed between TWI 0 and TWI 1 or between TWI 0 and TWI 2 (P > 0.05). However, increases in ABD were observed between TWI 0 and TWI 3 (P < 0.01), TWI 1 and TWI 3 (P < 0.01), TWI 1 and TWI 2 (P < 0.05) and TWI 2 and TWI 3 (P < 0.05). In addition, ABH was found to increase with increase in wear, with the exception of the interval between TWI 0 and TWI 1. Occlusal tooth wear does not result in any radiologically identifiable changes in the alveolar bone during the initial stages of wear; however, significant increases in both ABD and ABH may be observed as tooth wear progresses.

Serum Bone Biomarkers and Oral/Systemic Bone Loss in Humans

We recently reported that subantimicrobial-dose doxycycline (SDD) significantly reduced serum bone-resorption biomarkers in subgroups of post-menopausal women. We hypothesize that changes in serum bone biomarkers are associated not only with systemic bone mineral density (BMD) changes, but also with alveolar bone changes over time. One hundred twenty-eight eligible post-menopausal women with periodontitis and systemic osteopenia were randomly assigned to receive SDD or placebo tablets twice daily for two years, adjunctive to periodontal maintenance. Sera were analyzed for bone biomarkers. As expected, two-year changes in a serum bone biomarker were significantly associated with systemic BMD loss at the lumbar spine (osteocalcin, bone-turnover biomarker, p = 0.0002) and femoral neck (osteocalcin p = 0.0025). Two-year changes in serum osteocalcin and serum pyridinoline-crosslink fragment of type I collagen (ICTP; bone-resorption biomarker) were also significantly associated with alveolar bone density loss (p < 0.0001) and alveolar bone height loss (p = 0.0008), respectively. Thus, we have shown that serum bone biomarkers are associated with not only systemic BMD loss, but with alveolar bone loss as well. Clinical Trial Registration Information: Protocol registered at ClinicalTrials.gov, NCT00066027. Abbreviations: bone mineral density (BMD), bone-specific alkaline phosphatase (BSAP), computer-assisted densitometric image analysis (CADIA), confidence interval (CI), deoxypyridinoline-containing degradation fragment of the C-terminal telopeptide region of type I collagen (CTX), coefficient of variation (CV), dual-energy x-ray absorptiometry (DXA), pyridinoline-crosslink-containing degradation fragment of the C-terminal telopeptide region of type I collagen (ICTP), and subantimicrobial-dose doxycycline (SDD).

Quantitative analysis of bone density in direct digital radiographs evaluated by means of computerized analysis of digital images

minimal density variations of mineralized tissues can be reliably detected with quantitative image subtraction analysis. The aim of this study was to evaluate quantitative variations of in vitro mineral density by varying the exposure time of direct digital radiographs using a computer assisted densitometric image analysis (CADIA) program. in a human mandibular segment a three-wall periodontal defect was created mesial to a molar. Bone chips were created from the marrowbone of the same mandible with masses of 1 to 5 mg. A triplicate radiograph of the defect was taken as a baseline for seven different exposure times. The bone chips were inserted into the defect and another triplicate series of radiographs for the seven exposure times were taken as follow-up images. The images were analysed using CADIA software to detect variations in bone density. the results of CADIA revealed increased density when the size of the inserted bone chip increased. The 2 mg chip was underestimated owing to mass reduction during insertion. The regression line of the CADIA values was consistent with the weight of the bone chips of 1, 3, 4 and 5 mg. The exposure time f6 (0.178 s) showed the best correlation with the bone chip weight. Loss of information in the images occurred when the exposure time exceeded the sensor's latitude. CADIA analysis is a reliable and sensitive tool for detecting subtle bone density variations. More reliable results are obtained with increased exposure time; however, excessive exposure should be avoided.

Cigarette Smoking and Alveolar Bone in Young Adults: A Study Using Digitized Radiographs

Evidence indicates that cigarette smoking is one of the most significant risk factors for periodontal diseases; however, there have been few radiographic prospective studies of alveolar bone in young populations. The purpose of this study was to evaluate the effect of smoking on alveolar bone in young adults. Eighty-one dental students (mean age: 20.5 years), considered not to have periodontitis according to clinical criteria, participated in this study. Forty-two subjects were smokers (mean consumption was 14.1 cigarettes/day for > or =2 years), and 39 subjects had never smoked. A parallel-arm prospective design was used. All subjects took part in a dental hygiene program (DHP) that included oral hygiene instructions, mechanical debridement, and polishing. The following clinical variables were measured before and after the DHP: plaque index (PI), gingival crevicular fluid (GCF) flow rate, gingival index (GI), probing depth, and clinical attachment level (CAL). Standardized posterior vertical bitewing radiographs were taken and digitized preexperimentally and on days 180, 365, and 545. The following analyses were performed: bone height measurement (BHM), computer-assisted densitometric image analysis (CADIA), and qualitative analysis of digital subtraction radiography (DSR). Repeated-measures multiple-way analysis of variance (ANOVA) was performed between the groups, and one-way ANOVA was performed within the groups. The mean PI and GI were significantly greater in the smokers (P <0.01). The mean GCF flow rate was significantly lower in the smokers (P <0.01). CAL and the number of sites with recession were significantly greater in the smokers (P <0.001). The BHM indicated a significantly lower mean alveolar bone height in the smokers (P <0.01). The smokers showed significantly lower CADIA values, which indicated a lower bone density on days 0 (P <0.05), 180, 365, and 545 (P <0.01). CADIA values decreased during the study in the smokers, with significant differences on day 545 (P <0.05). The smokers had a significantly higher mean percentage of sites that had decreased density, as assessed by DSR (P <0.001). In the smokers, the mean percentage of sites with decreased density, as assessed by DSR, had increased significantly by days 365 (P <0.05) and 545 (P <0.01). Smoking produces an adverse effect on clinical periodontal variables and alveolar bone height and density, acting as a potential risk factor for alveolar bone loss, even at an early age with low tobacco consumption. It is very important to inform young smokers about the risk of this habit in relation to periodontal health.

Subantimicrobial dose doxycycline effects on alveolar bone loss in post‐menopausal women

Determine the efficacy of 2-year continuous subantimicrobial dose doxycycline (SDD; 20 mg bid) on alveolar bone in post-menopausal osteopenic, oestrogen-deficient women undergoing periodontal maintenance in a 2-year double-blind, placebo-controlled, randomized clinical trial. One-hundred and twenty-eight subjects randomized to SDD or placebo (n=64 each). Posterior vertical bite wings taken at baseline, 1 and 2 years for alveolar bone density (ABD), using radiographic absorptiometry (RA) and computer-assisted densitometric image analysis (CADIA), and alveolar bone height (ABH). Statistical analyses utilized generalized estimating equations; primary analyses were intent to treat (ITT). Results are presented as SDD versus placebo. Under ITT, there was no statistically significant effect of SDD on ABD loss (RA: p=0.8; CADIA: p=0.2) or ABH loss (p=0.2). Most sites (81-95%) were inactive. For subgroup analyses, mean CADIA was higher with SDD for non-smokers (p=0.05) and baseline probing depths > or =5 mm (p=0.003). SDD was associated with 29% lower odds of more progressive ABH loss in women >5 years post-menopausal (p=0.05) and 36% lower among protocol-adherent subjects (p=0.03). In post-menopausal osteopenic women with periodontitis, SDD did not differ overall from placebo. Based on exploratory subgroup analyses, additional research is needed to determine the usefulness of SDD in non-smokers, subjects >5 years post-menopausal and in deeper pockets. Protocol registered at (ClinicalTrials.gov). Identifier: NCT00066027.

Evaluation of peri-implant bone density changes in Brånemark implants by computer assisted densitometric image analysis (CADIA)

Evaluation of peri-implant bone density changes in Brånemark implants by computer assisted densitometric image analysis (CADIA)

Healing, post‐operative morbidity and patient perception of outcomes following regenerative therapy of deep intrabony defects

This prospective multicenter randomized controlled clinical trial was designed to compare the clinical outcomes of papilla preservation flap surgery with or without the application of enamel matrix derivatives (EMD). This article reports on early healing events, post-operative morbidity and patient perceptions of the surgical outcomes. One hundred and seventy-two patients with advanced chronic periodontitis and at least one intrabony defect of > or =3 mm were recruited in 12 centres in seven countries (European Research Group on Periodontology (ERGOPERIO)). Papilla preservation flaps were used to obtain access and primary closure. After debridement, and root conditioning, EMD was applied in the test subjects, and omitted in the controls. Healing was monitored 1, 2, 3, 4, 6 and 12 weeks after surgery. During the first 12 weeks of healing, supracrestal soft-tissue density was evaluated with a computer-assisted densitometric image analysis system (CADIA) using underexposed radiographs taken on a subset of 34 patients. Patient perceptions were evaluated with a questionnaire immediately after the procedure, at suture removal 1 week later and at 1 year. Subjects reported little intraoperative or post-operative pain or discomfort for both test and controls. Twenty-four percent of controls and 30% of tests (p=0.64) reported a degree of interference with daily activities for an average of 3 and 3.5 days, respectively. Post-surgical edema was noted in 25% of tests and 28% of controls. Wound dehiscence in the interdental portion of the flap was uncommon (14% of tests and 12% of controls at week 1) and of limited size. Root sensitivity was the most frequent post-operative adverse event: it affected 45% of test and 35% of controls (p=0.55). Up to 6 weeks post-operatively, soft-tissue densities were significantly higher in subjects treated with EMD with respect to controls. One year after completion of the surgery, patients reported high levels of satisfaction with the outcomes. The most frequently reported benefits included the ability to preserve a tooth/dentition and to maintain/improve chewing ability. The cost and need for frequent follow-ups were cited as significant drawbacks. This study portrayed the early healing events, pain, discomfort and adverse events of papilla preservation flap surgery and the 1-year patient perceptions of the benefits and disadvantages of periodontal surgery in intrabony defects. Earlier gains in soft-tissue density were observed following application of EMD. In terms of patient-centered outcomes, however, both procedures performed in a similar manner.

Treatment of simple bone cysts with aspiration and a single bone marrow injection.

The authors report the results of percutaneous aspiration and injection of marrow into active, simple bone cyst in 17 cases. Slow regression of the cyst and progressive healing were obtained in 13 cases (76%), no response was observed in 2 cases (12%), and recurrence was observed in 2 others (12%) after a follow-up of 33.9 months. Cyst evolution was monitored by a cyst index, cyst diameter, and computer-assisted densitometric image analysis of serial radiographs.

Treatment of Simple Bone Cysts With Aspiration and a Single Bone Marrow Injection

The authors report the results of percutaneous aspiration and injection of marrow into active, simple bone cyst in 17 cases. Slow regression of the cyst and progressive healing were obtained in 13 cases (76%), no response was observed in 2 cases (12%), and recurrence was observed in 2 others (12%) after a follow-up of 33.9 months. Cyst evolution was monitored by a cyst index, cyst diameter, and computer-assisted densitometric image analysis of serial radiographs.

In vitro calibration and validation of a digital subtraction radiography system using scanned images.

To calibrate and validate a digital subtraction radiography system using scanned images for quantification of alveolar bone changes by means of computer-assisted densitometric image analysis (CADIA) in vitro. Noise levels were determined using 10 standardized periapical radiographs of the same lower molar region in a human dry skull. For validation of the system, radiographs were taken before and after bovine bone particles in measures with increments of 2 mg weighing from 2 to 20 mg were added into each socket of three dry skulls. Radiographs were developed and scanned into a computer with a flatbed scanner. After digitization, the images were subjected to alignment, normalization and subtraction. Appropriate regions of interest (ROIs) were selected and their CADIA values were calculated for the determination of noise levels, and correlations between the CADIA values and the actual bone mass were performed. When the threshold value was 7, the percentage of pixels deviating from the set threshold value was small (0-11.3%). There were statistically significant correlations between the actual bone mass and the CADIA value for anterior sockets (p<0.001, r2=0.89) and posterior sockets (p<0.001, r2=0.9). For pooled data of both anterior and posterior sockets, the correlation was also statistically significant (p<0.001, r2=0.88). A high and statistically significant correlation between the actual bone mass and CADIA value was obtained, which suggests that the system could be suitable for the detection of small alveolar bone changes.

In vitro assessment of incipient approximal carious lesions using computer-assisted densitometric image analysis

Objectives. To investigate the use of computer-assisted densitometric image analysis (CADIA) to detect incipient approximal carious lesions in vitro and to compare areas of demineralization and mechanically induced lesions by radiographic visual inspection. Methods. Thirty-six extracted non-carious human molars were demineralized in a defined approximal area of interest (AOI) using a gel system (pH 4.8) applied over 15 weeks. Standardized digital radiographs were taken before and after creation of caries-like lesions and grayscale values were measured within the AOI. For another group of eight teeth, artificial defects were mechanically induced by a diamond bur and densitometric analysis was performed. Statistical significance was tested using the Wilcoxon test and set at p≤0.05. In addition, radiographs were interpreted by visual examination by six experienced dentists. The sensitivity and specificity for both study groups were determined in comparison to a baseline group of untreated teeth. Polarized light microscopy and SEM analysis were used to evaluate changes in the subsurface mineralization pattern and surface micromorphology. Results. Densitometric comparison of images from identical regions in control teeth revealed no significant grayscale value differences within the AOI, whereas a significant decrease ( p≤0.05) was observed in the demineralized group. Mechanically induced lesions also showed a significant densitometric decrease ( p≤0.05). The sensitivity of visual inspection of radiographs of demineralized areas was 0%. In contrast, the sensitivity for the detection of a mechanical defect of 0.1 mm, which was the same subsurface extension as the histologically determined demineralization, increased to 52%. Specificity was 100% for all groups. Conclusions. CADIA is able to detect very small changes in mineralization of incipient carious approximal lesions in vitro. The findings presented in this investigation may improve the subtraction method used for diagnosis and monitoring of approximal caries, as well as prophylactic measures.

Study of mandibular fracture repair using quantitative radiodensitometry: A comparison between maxillomandibular and rigid internal fixation

Purpose: This prospective study evaluated mandibular fracture repair after either maxillomandibular fixation (MMF) or rigid internal fixation (RIF) using the computer-assisted densitometric image analysis (CADIA) system. Patients and Methods: Fifty-two patients, 32 treated by MMF and 20 by RIF, were studied. Five postoperative panoramic radiographs were performed on each patient (immediately postoperatively and at 15, 30, 60, and 90 days) and the changes occurring in the optical density of the bone at and around the fracture line were analyzed. Results: An increase in optic density was observed in both groups at 15 days after treatment. At 30 days, a decrease in optical density was observed in both groups, being significantly greater in the MMF group. In the measurements performed at 60 days, an increased density was found in the RIF group, but the rate of optical density increase was more rapid in the MMF group. During the third month, the rates of optical density increase were similar in the 2 groups. Conclusions: The use of RIF results in more rapid bone mineralization than the use of MMF. © 2000 American Association of Oral and Maxillofacial Surgeons

Radiographic and Digital Imaging in Periodontal Practice

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 alveolar bone loss in postmenopausal osteoporotic/osteopenic women.

The purpose of this 2-year longitudinal clinical study was to investigate alveolar (oral) bone height and density changes in osteoporotic/osteopenic women compared with women with normal lumbar spine bone mineral density (BMD). Thirty-eight postmenopausal women completed this study; 21 women had normal BMD of the lumbar spine, while 17 women had osteoporosis or osteopenia of the lumbar spine at baseline. All subjects had a history of periodontitis and participated in 3- to 4-month periodontal maintenance programs. No subjects were current smokers. All patients were within 5 years of menopause at the start of the study. Four vertical bitewing radiographs of posterior sextants were taken at baseline and 2-year visits. Radiographs were examined using computer-assisted densitometric image analysis (CADIA) for changes in bone density at the crestal and subcrestal regions of interproximal bone. Changes in alveolar bone height were also measured. Radiographic data were analyzed by the t-test for two independent samples. Osteoporotic/osteopenic women exhibited a higher frequency of alveolar bone height loss (p<0.05) and crestal (p<0.025) and subcrestal (p<0.03) density loss relative to women with normal BMD. Estrogen deficiency was associated with increased frequency of alveolar bone crestal density loss in the osteoporotic/osteopenic women and in the overall study population (p<0.05). These data suggest that osteoporosis/osteopenia and estrogen deficiency are risk factors for alveolar bone density loss in postmenopausal women with a history of periodontitis.

Computer-assisted densitometric image analysis of digital subtraction images: in vivo error of the method and effect of thresholding.

The aim of the present study was to assess the in vivo error of the method as well as the effect of thresholding when obtaining and evaluating standardized periapical radiographs for computer-assisted densitometric image analysis (CADIA). Twenty healthy volunteers participated in an experimental gingivitis study in which neither mechanical nor chemical plaque control was performed for 21 days. Two pairs of standardized periapical radiographs were taken at days 0 (baseline) and 21 (follow-up), one from a maxillary area (15 volunteers) and one from a mandibular molar/premolar area (17 volunteers). Each baseline radiograph was digitized and its image displayed on a monitor. The follow-up radiograph was then superimposed and digitized as well. After gray level correction, subtraction radiographic images were produced. The difference in gray level between the baseline and the follow-up image was calculated within each region of interest (ROI) at each picture point (pixel). In bone ROI, changes in density reflected the amount of change due to methodological errors plus the basic bone remodeling over 3 weeks. For gingival ROI, changes in density reflected the methodological error plus a possible change in soft tissue density during the experimental gingivitis. Within all of the ROI, some pixels indicated a change in gray level. A change in gray level was then thresholded; i.e., only changes >5 and then >10 gray levels were registered and used for calculation of the CADIA values. With a threshold of 5, 44/45 maxillary bone ROI and 60/66 mandibular bone ROI showed a change in density, while 41/45 maxillary gingiva ROI and 26/66 mandibular gingiva ROI indicated a change in density. With a threshold of 10, 16/45 maxillary bone ROI and 12/66 mandibular bone ROI indicated a change in density, while 13/45 maxillary gingiva ROI and 1/66 mandibular gingiva ROI indicated a change. The amounts of changes in density calculated in the various ROI were low even when applying no threshold, ranging from -0.279 to 0.621. Applying a threshold of 5, the CADIA values ranged from -0.234 to 0.727. With a threshold of 10, the changes in density ranged from -0.318 to 0.133. In vivo, CADIA of standardized radiographs indicated change in density due to methodological errors. Application of thresholds may avoid false-positive diagnoses. When applying CADIA in clinical research, the range of change to be expected due to methodological limitations as well as the threshold for true change should be evaluated. These thresholds may differ in various areas of the mouth, i.e., bone or gingival, maxillary/mandibular, anterior/posterior ROI.

Hydroxyapatite cement implant for regeneration of periodontal osseous defects in humans.

A newly developed calcium phosphate cement used to promote bone regeneration in craniofacial defects was examined to determine its potential for treatment of periodontal osseous defects. Sixteen patients with moderate to severe periodontal disease and 2 bilaterally similar vertical bony defects received initial therapy including scaling and root planing followed by treatment with either calcium phosphate cement, flap curettage (F/C) or debridement plus demineralized freeze-dried bone allograft (DFDBA). Standardized radiographs were exposed at baseline and 12 months postsurgery for computer assisted densitometric image analysis (CADIA). The extent of the bony defect was determined during initial and 12 month re-entry surgery. Within 6 months of implant placement, 11 of 16 patients treated with calcium phosphate cement exfoliated all or most of the implant through the gingival sulcus. At all 16 test sites, a narrow radiolucent gap formed by 1 month postsurgery at the initially tight visual interface between the radiopaque calcium phosphate cement and the walls of the bony defect. Mean probing depth reduction and clinical attachment gain at sites treated with calcium phosphate cement were 1.6 mm and 1.3 mm, respectively at 1 year. Minimal bony defect fill was accompanied by mean crestal resorption of 1.4 mm. Alveolar crestal resorption at sites with calcium phosphate cement was statistically significant (P=0.001). These findings contrasted with the more favorable outcomes for controls treated with DFDBA or F/C. DFDBA sites exhibited probing depth reduction of 3.1 mm, clinical attachment gain of 2.9 mm, and defect fill of 2.4 mm. Respective clinical changes at F/C sites were 2.4 mm, 1.4 mm, and 1.1 mm. CADIA revealed clinically significant trends between the three treatment modalities at various areas-of-interest. Based on the findings of this study, there is no rationale available to support the use of hydroxyapatite cement implant in its current formulation for the treatment of vertical intrabony periodontal defects.