Radiographic diagnosis in periodontics

Artificial intelligence models for diagnosing gingivitis and periodontal disease: A systematic review

STATEMENT OF PROBLEM

Artificial intelligence (AI) models have been developed for periodontal applications, including diagnosing gingivitis and periodontal disease, but their accuracy and maturity of the technology remain unclear.

PURPOSE

The purpose of this systematic review was to evaluate the performance of the AI models for detecting dental plaque and diagnosing gingivitis and periodontal disease.

MATERIAL AND METHODS

A review was performed in 4 databases: MEDLINE/PubMed, World of Science, Cochrane, and Scopus. A manual search was also conducted. Studies were classified into 4 groups: detecting dental plaque, diagnosis of gingivitis, diagnosis of periodontal disease from intraoral images, and diagnosis of alveolar bone loss from periapical, bitewing, and panoramic radiographs. Two investigators evaluated the studies independently by applying the Joanna Briggs Institute critical appraisal. A third examiner was consulted to resolve any lack of consensus.

RESULTS

Twenty-four articles were included: 2 studies developed AI models for detecting plaque, resulting in accuracy ranging from 73.6% to 99%; 7 studies assessed the ability to diagnose gingivitis from intraoral photographs reporting an accuracy between 74% and 78.20%; 1 study used fluorescent intraoral images to diagnose gingivitis reporting 67.7% to 73.72% accuracy; 3 studies assessed the ability to diagnose periodontal disease from intraoral photographs with an accuracy between 47% and 81%, and 11 studies evaluated the performance of AI models for detecting alveolar bone loss from radiographic images reporting an accuracy between 73.4% and 99%.

CONCLUSIONS

AI models for periodontology applications are still in development but might provide a powerful diagnostic tool.

Cone-Beam Computed Tomography in Periodontal Diagnosis and Treatment Planning

Diagnosis of periodontal disease depends on conventional clinical parameters. In periodontitis with extensive bone defects, radiographs play a crucial role in arriving at a proper diagnosis. The emergence of cone-beam computed tomography (CBCT) became a boon in oral radiology. Limitations of conventional two-dimensional (2D) radiographs include inadequate visualization of bone defects, lamina dura, and furcation involvement. CBCT generates 3D images of anatomical structures necessary for the periodontal diagnosis of furcation involvement, intrabony defects, and implant placement. CBCT, thus, imparts various potential applications in the field of periodontics which serves to arrive at better diagnostic conclusions.

Assessment of alveolar bone changes in response to minimally invasive periodontal surgery: A cone-beam computed tomographic evaluation

Purpose

The aim of this study was to evaluate 3-dimensional cone-beam computed tomography (CBCT) images of alveolar bone changes in patients who underwent minimally invasive periodontal surgery-namely, the pinhole surgical technique (PST).

Materials and Methods

Alveolar bone height was measured and compared on CBCT images of 254 teeth from 23 consecutive patients with Miller class I, II, or III recession who had undergone PST. No patient with active periodontal disease was selected for surgery. Two different methods were used to assess the alveolar bone changes postoperatively. In both methods, the distance between the apex of the tooth and the mid-buccal alveolar crestal bone on pre- and post-surgical CBCT studies was measured.

Results

An average alveolar bone gain >0.5 mm following PST was identified using CBCT (P=0.05). None of the demographic variables, including sex, age, and time since surgery, had any significant effect on bone gain during follow-up, which ranged from 8 months to 3 years.

Conclusion

PST appears to be a promising treatment modality for recession that results in stable clinical outcomes and may lead to some level of resolution on the bone level. More long-term studies must be done to evaluate the impact of this novel technique on bone remodeling and to assess sustained bone levels within a larger study population.

Do Radiographic Assessments of Periodontal Bone Loss Improve with Deep Learning Methods for Enhanced Image Resolution?

Resolution plays an essential role in oral imaging for periodontal disease assessment. Nevertheless, due to limitations in acquisition tools, a considerable number of oral examinations have low resolution, making the evaluation of this kind of lesion difficult. Recently, the use of deep-learning methods for image resolution improvement has seen an increase in the literature. In this work, we performed two studies to evaluate the effects of using different resolution improvement methods (nearest, bilinear, bicubic, Lanczos, SRCNN, and SRGAN). In the first one, specialized dentists visually analyzed the quality of images treated with these techniques. In the second study, we used those methods as different pre-processing steps for inputs of convolutional neural network (CNN) classifiers (Inception and ResNet) and evaluated whether this process leads to better results. The deep-learning methods lead to a substantial improvement in the visual quality of images but do not necessarily promote better classifier performance.

Are there correlations between radiographic grade levels and modified grade levels of periodontitis?

BACKGROUND

At the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions, periodontitis was reclassified according to a multidimensional staging and grading system. Grading takes variabilities in the rate of disease progression into account, relying on recognized progression risk factors, and is based on the assessment of bone loss at the worst-affected tooth in the dentition as a function of age, which is then modified by factors such as smoking and diabetes mellitus. In this context, the aim of this study was to determine whether there are correlations between radiographically calculated grades and grades modified by the presence of smoking or diabetes.

MATERIALS AND METHODS

In this descriptive study, individuals diagnosed with periodontitis according to the 2017 classifications were examined. The grade of periodontitis was measured using periapical radiography. A modified-grade level was assigned to the patients according to their glycated hemoglobin levels (in diabetics) or their smoking status.

RESULTS

The study included 341 individuals. No statistically significant relationship was revealed by Chi-square testing (P > 0.05) or in the kappa agreement index between the modified grades and the radiographic grades.

CONCLUSIONS

Although there was no correlation between radiographic grade and modified grade in smokers and diabetic individuals, increasing the grade score in these individuals in accordance with the 2017 classification provides clinicians the opportunity to develop a risk-based treatment plan, commensurate with the severity of periodontal disease and the level of risk.

Diagnostic accuracy of CBCT versus intraoral imaging for assessment of peri-implant bone defects

Background

Early detection of marginal bone loss is vital for treatment planning and prognosis of teeth and implant. This study was conducted to assess diagnostic accuracy of CBCT compared to intra-oral (IO) radiography for detection, classification, and measurement of peri-implant bone defects in an animal model.

Methods

Fifty-four mandible blocks with implants were harvested from nine male health adult beagle dogs with acquisition of IO, CBCT and micro-CT images from all samples. Peri-implant bone defects from 16 samples were diagnosed using micro-CT and classified into 3 defect categories: dehiscence (n = 5), infrabony defect (n = 3) and crater-like defect (n = 8). Following training and calibration of the observers, they asked to detect location (mesial, distal, buccal, lingual) and shape of the defect (dehiscence, horizontal defect, vertical defect, carter-like defect) utilizing both IO and CBCT images. Both observers assessed defect depth and width on IO, CBCT and micro-CT images at each side of peri-implant bone defect via CT-analyzer software. Data were analyzed using SPSS software and a p value of < 0.05 was considered as statistically significant.

Results

Overall, there was a high diagnostic accuracy for detection of bone defects with CBCT images (sensitivity: 100%/100%), while IO images showed a reduction in accuracy (sensitivity: 69%/63%). Similarly, diagnostic accuracy for defect classification was significantly higher for CBCT, whereas IO images were unable to correctly identify vestibular dehiscence, with incorrect assessment of half of the infrabony defects. For accuracy of measuring defect depth and width, a higher correlation was observed between CBCT and gold standard micro-CT (r = 0.91, 95% CI 0.86–0.94), whereas a lower correlation was seen for IO images (r = 0.82, 95% CI 0.67–0.91).

Conclusions

The diagnostic accuracy and reliability of CBCT was found to be superior to IO imaging for the detection, classification, and measurement of peri-implant bone defects. The application of CBCT adds substantial information related to the peri-implant bone defect diagnosis and decision-making which cannot be achieved with conventional IO imaging.

Effect of voxel size on detection of fenestration, dehiscence and furcation defects using cone-beam computed tomography

OBJECTIVES

This study aimed to assess the effect of voxel size on detection of fenestration, dehiscence, and furcation defects using cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

This in vitro, experimental study evaluated 4 sheep skulls with both the maxilla and mandible accompanied by the surrounding soft tissue. Fenestration (n = 30), dehiscence (n = 65), and furcation defects (n = 46; 18 grade I, 25 grade II, and 3 grade III) were randomly created by round and needle burs in both jaws, and 40 areas served as control sites. CBCT scans were obtained with 0.300 and 0.150 mm³ voxel sizes and 8 × 11cm² field of view (FOV), and were randomly observed by four observers (two oral and maxillofacial radiologists and two periodontists). The kappa values, sensitivity and specificity were calculated for each voxel size and compared using paired t test.

RESULTS

By an increase in image resolution, diagnostic sensitivity increased while specificity decreased. The kappa values for fenestration (0.602-0.623), and grade III furcation defects (0.903-1.00) were optimal (> 0.6), and almost similar for both voxel sizes. The kappa values for dehiscence, and grades I and II furcation defects were unfavorable (< 0.6) and almost similar for both voxel sizes, except for grade I furcation defects, which had a significant difference in kappa values between the two voxel sizes (0.014 and 0.34).

CONCLUSION

Smaller voxel size had higher sensitivity and lower specificity for detection of all defects except for grade I furcation defects, for which the smaller voxel size had higher sensitivity and higher specificity.

Radiologic Assessment of the Periodontal Patient

Periodontal examination involves evaluation of soft and hard tissue parameters to gauge gingival inflammatory changes and quantify attachment loss. Conventional radiographs are vital components of this process and can be used to assess the presence of calculus and other local factors to establish a diagnosis, prognosis, and periodontal treatment plan. The 2-dimensional nature of these images limits their utility. The advent of high-resolution cone beam computed tomography (CBCT) offers 3-dimensional images that might overcome these limitations. We discuss the use of conventional radiographic techniques as well as CBCT for evaluating, diagnosing, and treatment planning patients presenting for periodontal and/or implant therapy.

Effect of in-situ application of simvastatin gel in surgical management of osseous defects in chronic periodontitis-A randomized clinical trial

BACKGROUND

The present randomized controlled clinical study was designed to investigate the effect of in situ application of 1.2 mg Simvastatin (SV) gel in the surgical management of Intrabony defects in chronic periodontitis patients.

METHODOLOGY

20 patients contributing 40 sites were categorized into two treatment groups: Open flap debridement plus 1.2 mg SV gel (Group 1) and Open flap debridement plus Placebo gel (Group 2). Gingival index (GI), Plaque index (PI), Pocket depth (PD) and clinical attachment level (CAL) were recorded at baseline, 3 months, 6 months and 9 months. At baseline and at the end of 6 and 9 months Radiographic evaluation of Intrabony defect fill was done using Image j software.

RESULTS

Significant reduction of GI, PD and gain in CAL was observed at the end of 9 months in both groups. Amount of bone fill and percentage of original defect fill in Group 1 was statistically highly significant than Group 2 at the end of 6 and 9 months.

CONCLUSION

Higher amount of decrease in GI and PD along with more amount of CAL gain was observed in treatment group than control group. Radiological assessment confirmed that significant intrabony defect fill and percentage fill of original defect in treatment group than controlled group.

The efficacy of transgingival probing in class II buccal furcation defects treated by guided tissue regeneration

Background:

The objectives of the present study were to establish transgingival probing as an evaluating method in the clinical studies of periodontal regenerative techniques and to compare the effectiveness of transgingival probing to the surgical entry.

Materials and Methods:

Ten systemically healthy persons (20–50 years) with moderate to severe chronic periodontitis participated in this study. These cases were recruited into the study only when they fulfilled the eligibility criteria. Vertical probing depth (VPD) and horizontal probing depth (HPD) of furcation defects were measured with and without opening the flap, following local anesthesia during initial surgery and at 6 months after collagen membrane placement. The defect fill (DF) was also noted. The mean measurements of clinical parameters were compared by two-tailed paired t-test at 5% level of significance.

Results:

The difference between the measurements of VPD and HPD taken during transgingival probing and after opening the flap was lie in the range of 0.10–0.30 mm at the time of initial surgery and 6 months after surgery that was not statistically significant. Persons experienced slight discomfort or pain during opening the flap as compared to transgingival probing, and this method was also appreciated by the patients as it is easy, simple and does not involve the surgical procedure.

Conclusion:

The results of the study suggest that measurements recorded during transgingival probing and after opening the flap do not influence the required outcome of regenerative therapies, i.e., DF that was not statistically significant difference from surgical reentry. Therefore, it was concluded that transgingival probing could be used as evaluating parameters to see the outcome of regenerative surgeries and the surgical reentry procedure may be avoided because it is a second surgical procedure, time-consuming and interrupts the healing process.

Comparisons of the diagnostic accuracies of optical coherence tomography, micro-computed tomography, and histology in periodontal disease: an ex vivo study

Purpose

Optical coherence tomography (OCT) is a noninvasive diagnostic technique that may be useful for both qualitative and quantitative analyses of the periodontium. Micro-computed tomography (micro-CT) is another noninvasive imaging technique capable of providing submicron spatial resolution. The purpose of this study was to present periodontal images obtained using ex vivo dental OCT and to compare OCT images with micro-CT images and histologic sections.

Methods

Images of ex vivo canine periodontal structures were obtained using OCT. Biologic depth measurements made using OCT were compared to measurements made on histologic sections prepared from the same sites. Visual comparisons were made among OCT, micro-CT, and histologic sections to evaluate whether anatomical details were accurately revealed by OCT.

Results

The periodontal tissue contour, gingival sulcus, and the presence of supragingival and subgingival calculus could be visualized using OCT. OCT was able to depict the surface topography of the dentogingival complex with higher resolution than micro-CT, but the imaging depth was typically limited to 1.2–1.5 mm. Biologic depth measurements made using OCT were a mean of 0.51 mm shallower than the histologic measurements.

Conclusions

Dental OCT as used in this study was able to generate high-resolution, cross-sectional images of the superficial portions of periodontal structures. Improvements in imaging depth and the development of an intraoral sensor are likely to make OCT a useful technique for periodontal applications.

Detection of simulated periodontal defects using cone-beam CT and digital intraoral radiography

OBJECTIVES:

This study sought to assess the diagnostic value of CBCT and digital intraoral radiography for the detection of periodontal defects in the sheep mandible.

METHODS:

In this in vitro study, 80 periodontal defects including Grades I, II and III furcation involvements, one-, two-, three-wall and trough-like infrabony defects, fenestration and dehiscence were artificially created in the sheep mandible by burr. Intraoral digital radiographs using photostimulable phosphor plates and CBCT scans were obtained. Three periodontists evaluated the images for the presence and type of defects. The results were compared with the gold standard (photographs of the created defects).

RESULTS:

CBCT scans were significantly superior to digital radiographs for the detection of Grade I furcation involvements, three-wall defects, fenestrations and dehiscence (p < 0.05). No significant difference was noted between CBCT and digital radiography for the detection of Grades II and III furcation involvements, one-wall, two-wall and trough-like defects (p-value > 0.05).

CONCLUSIONS:

CBCT was superior to digital intraoral radiography for the detection of Grade I furcation involvements, three-wall defects, dehiscence and fenestrations.

Choice of diagnostic and therapeutic imaging in periodontics and implantology

Imaging forms an integral component for diagnosis of dental and in specific periodontal diseases. To date, intra-oral radiographic techniques are the main non-invasive diagnostic aids for the detection and assessment of internal changes in mineralized periodontal tissues like alveolar bone. These analog radiographic techniques suffer from inherent limitations like: Two dimensional projection, magnification, distortion, superimposition and misrepresentation of anatomic structures. The evolution of novel imaging modalities, namely cone beam computed tomography, tuned aperture CT empowered dental researchers to visualize the periodontium three dimensionally. This improves interpretation of structural and biophysical changes, ensures densitometric assessments of dentoalveolar structures including variations in alveolar bone density, and peri-implant bone healing more precisely. This detailed review, highlights current leading edge concepts, envisions a wide range of imaging modalities which pave the way for better understanding and early intervention of periodontal diseases.

Diagnostic Applications of Cone-Beam CT for Periodontal Diseases

Objectives. This paper aims to review the diagnostic application of cone beam computed tomography (CBCT) in the field of periodontology. Data. Original articles that reported on the use of CBCT for periodontal disease diagnosis were included. Sources. MEDLINE (1990 to January 2014), PubMed (using medical subject headings), and Google Scholar were searched using the following terms in different combinations: “CBCT,” “volumetric CT,” “periodontal disease ,” and “periodontitis.” This was supplemented by hand-searching in peer-reviewed journals and cross-referenced with the articles accessed. Conclusions. Bony defects, caters, and furcation involvements seem to be better depicted on CBCT, whereas bone quality and periodontal ligament space scored better on conventional intraoral radiography. CBCT does not offer a significant advantage over conventional radiography for assessing the periodontal bone levels.

Diagnostic accuracy of CBCT for periodontal lesions

OBJECTIVES

The present study compares the diagnostic value of periodontal bone defect images using conventional two-dimensional single-tooth radiographs and three-dimensional cone beam computed tomography (CBCT) images.

MATERIALS AND METHODS

Classified periodontal bone defects were prepared on pig mandibles and presented radiographically. Fifteen dentists were instructed to make a diagnosis based on these x-rays, regarding the type and the extent of the bone defects. Subsequently, the results were evaluated and compared to the morphology of the surgically prepared defects as the gold standard.

RESULTS

On average, the diagnosis of infrabony defects were 21 %, dehiscence 25 %, and fenestration 33 % more accurate using the three-dimensional projection than with the single-tooth radiograph. Furthermore, the CBCT allows grade II furcation to be captured more accurately.

CONCLUSIONS

The results of this study indicate that a considerably more precise analysis of periodontal defects is possible due to the third dimension. Particularly, in the oro-vestibular orientation, defects could be detected significantly more accurate.

CLINICAL RELEVANCE

CBCT images offer an advantageous alternative to the conventional single-tooth radiograph while taking the higher exposure of radiation into account.

New developments in tools for periodontal diagnosis

OBJECTIVES

For decades there has been increasing focus on the development of clinically acceptable, more sensitive and specific methods for the accurate and non-invasive diagnosis and prognosis of periodontitis. There are several well-known inherent drawbacks to current clinical procedures. The purpose of this article is to summarise some of the newly emerging diagnostic approaches, namely: the ultrasonographic probe; cone-beam computed tomography; optical coherence tomography; optical spectroscopy, and proteome analysis.

RESULTS

These novel diagnostic tools complement one another and, together with conventional clinical and radiographic examination, are likely to provide more accurate methods of diagnosing periodontitis. However, these techniques are yet to be clinically validated and their potential interpreted.

CONCLUSIONS

For the clinician, the planning of therapy is probably the most critical and difficult step in the treatment of patients with periodontal disease. A new paradigm for periodontal diagnosis will certainly increase understanding of periodontal diseases, which may eventually optimise the predictability of treatment and improve the clinical management of patients with periodontal disease.

Evaluation of an aminobisphosphonate (alendronate) in the management of periodontal osseous defects

Background and Objectives:

Alendronate, an aminobisphosphonate, is capable of inhibiting periodontitis associated osteoclastic activity and hence is effective in protecting the alveolar bone in periodontitis. In the present study, we explored the efficacy of local delivery of alendronate on the alveolar bone following mucoperiosteal flap surgery. This is the first study to use polymer impregnated gel based delivery of alendronate.

Materials and Methods:

A total of 15 patients with chronic periodontitis in the age group of 35 - 55 years, of both sexes, with pocket depth of ≥ 5mm and radiographic evidence of identical osseous defects in the mandibular molar region bilaterally were included in this prospective study. A gel based drug delivery system of Alendronate was formulated. Following surgical flap debridement, 0.1 ml alendronate gel and 0.1 ml placebo gel was placed at the experimental and control sites respectively. Clinical and radiographic parameters were recorded at baseline, three months and six months post surgery.

Results:

Alendronate was more effective in improving clinical and radiographic parameters compared to placebo.

Interpretation and Conclusion:

Alendronate is effective in the management of periodontitis associated bone loss. Gel based local delivery of the drug addresses the critical concern of exposing the patient to adverse effects of systemic administration.

Association between periodontal disease and osteoporosis in postmenopausal women in jordan

BACKGROUND

Some studies suggest that females with osteoporosis are at an increased risk of periodontal attachment loss and tooth loss; however, results have varied. The aim of this study is to determine the relationship between periodontitis and osteoporosis among postmenopausal Jordanian women.

METHODS

This cross-sectional study includes 400 Jordanian postmenopausal women with a mean age of 62.5 years (SD ± 6.4 years). These subjects were recruited from patients who had received a routine dual-energy x-ray absorptiometry examination in the Radiology Department, King Abdullah Hospital, Jordan University of Science and Technology, between June 2008 and February 2009. The relationship between skeletal bone mineral density (BMD) and radiographic and clinical parameters of periodontal status, including the loss of alveolar crestal height (ACH), clinical attachment level, probing depth, and percentage of sites with bleeding on probing, was evaluated after controlling for known confounders.

RESULTS

Bivariate analyses revealed no significant differences in the severity and extent of clinical attachment and ACH loss among women with normal BMD, osteopenia, and osteoporosis. However, in the multivariate analysis, women with osteoporosis were more likely to have severe ACH loss (odds ratio [OR]: 4.20; 95% confidence interval [CI]: 1.57 to 11.22) and periodontitis (OR: 2.45; 95% CI: 1.38 to 4.34).

CONCLUSION

Osteoporosis was significantly associated with severe alveolar crestal bone loss and the prevalence of periodontitis cases in postmenopausal Jordanian women.

Digital subtraction radiographic analysis of the combination of bioabsorbable membrane and bovine morphogenetic protein pool in human periodontal infrabony defects

OBJECTIVES

This study assessed the bone density gain and its relationship with the periodontal clinical parameters in a case series of a regenerative therapy procedure.

MATERIAL AND METHODS

Using a split-mouth study design, 10 pairs of infrabony defects from 15 patients were treated with a pool of bovine bone morphogenetic proteins associated with collagen membrane (test sites) or collagen membrane only (control sites). The periodontal healing was clinically and radiographically monitored for six months. Standardized pre-surgical and 6-month postoperative radiographs were digitized for digital subtraction analysis, which showed relative bone density gain in both groups of 0.034 ± 0.423 and 0.105 ± 0.423 in the test and control group, respectively (p>0.05).

RESULTS

As regards the area size of bone density change, the influence of the therapy was detected in 2.5 mm² in the test group and 2 mm² in the control group (p>0.05). Additionally, no correlation was observed between the favorable clinical results and the bone density gain measured by digital subtraction radiography (p>0.05).

CONCLUSIONS

The findings of this study suggest that the clinical benefit of the regenerative therapy observed did not come with significant bone density gains. Long-term evaluation may lead to a different conclusions.

High-resolution 3D ultrasound jawbone surface imaging for diagnosis of periodontal bony defects: an in vitro study

Although medical specialties have recognized the importance of using ultrasonic imaging, dentistry is only beginning to discover its benefit. This has particularly been important in the field of periodontics which studies infections in the gum and bone tissues that surround the teeth. This study investigates the feasibility of using a custom-designed high-frequency ultrasound imaging system to reconstruct high-resolution (< 50 μm) three-dimensional (3D) surface images of periodontal defects in human jawbone. The system employs single-element focused ultrasound transducers with center frequencies ranging from 30 to 60 MHz. Continuous acquisition using a 1 GHz data acquisition card is synchronized with a high-precision two-dimensional (2D) positioning system of ±1 μm resolution for acquiring accurate measurements of the mandible, in vitro. Signal and image processing algorithms are applied to reconstruct high-resolution ultrasound images and extract the jawbone surface in each frame. Then, all edges are combined and smoothed in order to render a 3D surface image of the jawbone. In vitro experiments were performed to assess the system performance using mandibles with teeth (dentate) or without (nondentate). The system was able to reconstruct 3D images for the mandible's outer surface with superior spatial resolution down to 24 μm, and to perform the whole scanning in < 30 s. Major anatomical landmarks on the images were confirmed with the anatomical structures on the mandibles. All the anatomical landmarks were detected and fully described as 3D images using this novel ultrasound imaging technique, whereas the 2D X-ray radiographic images suffered from poor contrast. These results indicate the great potential of utilizing high-resolution ultrasound as a noninvasive, nonionizing imaging technique for the early diagnosis of the more severe form of periodontal disease.

Influence of image filters on the reproducibility measurements of alveolar bone loss

The reproducibility of measurements of alveolar bone loss on radiographs may be a problem on epidemiologic studies, as they are based on comparisons of the diagnosis of various examiners. The aim of the present research paper was to assess the inter- and intra-examiner reproducibility of measurements of the interproximal alveolar bone loss on non-manipulated digital radiographs and after the application of image filters. Five Oral Radiologists measured the distance between the cementoenamel junction (CEJ) to the alveolar crest or to the deepest point of the bony defect on 12 interproximal digital radiographs of molars and bicuspids of a dry human skull. The digital manipulation and the linear measurements were obtained with the Trophy Windows software (Throphy®). For each image, six different versions were created: 1) non-manipulated; 2) bright-contrast adjustment; 3) negative; 4) negative with brightness-contrast adjustment; 5) pseudo-colored; 6) pseudo-colored with brightness-contrast adjustment. In order to prevent interpretation bias because of the repetition of measurements, the examiners measured the radiographs in a random sequence. The two-way ANOVA test at 5% level of significance to compare the means of readings of the same operator with each filter indicated p<0.05 for the majority of operators, while the comparison between the mean values of operators using the same filter indicated p>0.05 for all filters. Based on the results, we concluded that linear measurements of interproximal alveolar bone loss on digital radiographs are highly reproducible among examiners. Nevertheless, the application of image filters significantly influenced the degree of intra-examiner reproducibility. Some filters even reduced the reproducibility of intra-examiner readings.

A randomized clinical trial of autologous platelet-rich plasma in the treatment of mandibular degree II furcation defects

AIM

A combined technique using a platelet-rich plasma (PRP)/bovine porous bone mineral/guided tissue regeneration membrane was found to be an effective modality for the treatment of mandibular grade II furcation defects. To elucidate the role played by each component, the present randomized, double-blind study is designed to evaluate the effectiveness of autologous PRP alone in the treatment of mandibular degree II furcation defects compared with open flap debridement (OFD).

MATERIAL AND METHODS

Using a split-mouth design, 40 mandibular degree II furcation defects were treated either with autologous PRP or OFD. Plaque index, sulcus bleeding index, vertical probing depth, relative vertical and horizontal clinical attachment level and gingival marginal level were recorded at baseline and 6 months post-operatively. Vertical and horizontal defect depths were also recorded using spiral computed tomography.

RESULTS

A statistically significant difference was observed in all the clinical and radiographic parameters at the sites treated with PRP as compared with those with OFD. However, all the furcation defects retained their degree II status.

CONCLUSION

Despite a significant improvement, lack of complete closure of furcation defects implies a limited role of autologous PRP as a regenerative material in the treatment of furcation defects, necessitating further long-term studies.

Evaluation of high-resolution cone beam computed tomography in the detection of simulated interradicular bone lesions

OBJECTIVES

The purpose of this study is to assess the accuracy of limited-volume high-resolution cone beam CT (CBCT) in the detection of periodontal bone loss.

METHODS

163 simulated periodontal lesions of different depths were created in dried human hemimandibles. Specimens were imaged using the intraoral paralleling technique and limited-volume CBCT (3DX Accuitomo; Morita Co. Ltd, Kyoto, Japan). Ten viewers examined the images. Data were analysed with receiver operating characteristics (ROC) analysis. ROC curves were generated and the areas under the maximum-likelihood curves (A(z)) were compared. Other statistical analyses were used to detect the normality of the distribution of the results.

RESULTS

The results are reported as the individual viewer ROC curve areas for each of the two imaging modalities. In all experiments the A(z) area for CBCT (0.770-0.864) was larger than the A(z) area for periapical film (0.678-0.783); statistical tests showed a statistically significant difference between the two modalities.

CONCLUSIONS

Results indicate that the CBCT technique has better accuracy and diagnostic value than periapical films in the detection of interradicular periodontal bone defects.

Radiographic alveolar bone loss in patients undergoing periodontal maintenance

The aim of the present cross-sectional investigation was to evaluate percentage of bone loss in patients who had been one year under periodontal maintenance at the Department of Periodontology, Faculty of Dentistry, University of São Paulo by radiographic analysis. Complete sets of periapical radiographs provided data regarding percentage of alveolar bone loss, which was correlated with arches, tooth group and proximal sites. The sample consisted of 27 men and 53 women ranging in age from 16 to 85 years (mean: 48.3 years). A total of 1,120 periapical radiographs (1,970 teeth) were digitized and analyzed with the Image Tool software (University of Texas Health Science Center). Bone loss was defined as when the distance between the cemento-enamel junction and the alveolar bone crest was greater than 2 mm. Two examiners (p<0.0001) performed radiographic measurements of bone loss. The Greenhouse-Geisser normality test and a univariate analysis of variance were used for statistical analysis. Mean bone loss was 20.60% (+/-12.12). The highest level of bone loss was observed on the distal surface and in the upper arch, as well as in the upper incisors and molars.

An iterative point correspondence algorithm for automatic image registration: an application to dental subtraction radiography

In this paper, an Automatic Iterative Point Correspondence (AIPC) algorithm towards image registration is presented. Given an image pair, distinctive points are extracted only in one of the images (reference image), and the corresponding points in the other image are obtained automatically by maximizing a similarity measure between regions of the two images with respect to the parameters of a local transformation. The maximization is accomplished by means of an iterative procedure, in which candidate solutions for the transformation parameters are tested at each iteration; these solutions are evaluated by the similarity measure between image regions. The detected point pairs by the application of the AIPC algorithm are then used to estimate the parameters of a global projective transformation for the registration of the image pair. The proposed AIPC algorithm was applied on 113 in vitro and in vivo dental image pairs providing improved registration accuracy against three widely used registration methods.

In vitro cone beam computed tomography imaging of periodontal bone

OBJECTIVES

To assess the accuracy of NewTom 9000 cone beam CT (CBCT) images for the detection and quantification of periodontal bone defects in three dimensions.

METHODS

A sample of 146 sites in 5 dry skulls provided the ground truth (GT). Half of the sample had bone loss of at least 3 mm. Two metal spheres at each site ensured correspondence between GT and CBCT measurements. Skulls were submerged in water and scanned with the NewTom QR-DVT-9000. A full mouth series (FMX) was obtained of each skull using photostimulable phosphor plates. Six observers measured the bone height of each site and rated the presence or absence of bone loss. Measurements were compared to GT and A(z)-values were calculated from receiver operating characteristic curves.

RESULTS

The A(z)-value for CBCT was 0.74 (standard deviation (SD) = 0.14) and for FMX 0.48 (SD = 0.09). The difference was significant (ANOVA: P < 0.01). The diagnostic accuracy of CBCT was lower for anterior teeth (A(z) = 0.59) than for molars (A(z) = 0.82) and premolars (A(z) = 0.79) (Tukey's HSD (honestly significant difference): P < 0.01). The mean absolute difference between CBCT and GT was 1.27 mm (SD = 1.43) and between FMX and GT 1.49 mm (SE = 1.24) (ANOVA: P < 0.01). Measurements in the anterior mandible were less accurate than in other areas (Tukey's HSD: P < 0.01).

CONCLUSION

The NewTom 9000 cone beam CT scanner provides better diagnostic and quantitative information on periodontal bone levels in three dimensions than conventional radiography. The accuracy in the anterior aspect of the jaws is limited.

Case definitions for use in population-based surveillance of periodontitis

Many definitions of periodontitis have been used in the literature for population-based studies, but there is no accepted standard. In early epidemiologic studies, the two major periodontal diseases, gingivitis and periodontitis, were combined and considered to be a continuum. National United States surveys were conducted in 1960 to 1962, 1971 to 1974, 1981, 1985 to 1986, 1988 to 1994, and 1999 to 2000. The case definitions and protocols used in the six national surveys reflect a continuing evolution and improvement over time. Generally, the clinical diagnosis of periodontitis is based on measures of probing depth (PD), clinical attachment level (CAL), the radiographic pattern and extent of alveolar bone loss, gingival inflammation measured as bleeding on probing, or a combination of these measures. Several other patient characteristics are considered, and several factors, such as age, can affect measurements of PD and CAL. Accuracy and reproducibility of measurements of PD and CAL are important because case definitions for periodontitis are based largely on either or both measurements, and relatively small changes in these values can result in large changes in disease prevalence. The classification currently accepted by the American Academy of Periodontology (AAP) was devised by the 1999 International Workshop for a Classification of Periodontal Diseases and Conditions. However, in 2003 the Centers for Disease Control and Prevention and the AAP appointed a working group to develop further standardized clinical case definitions for population-based studies of periodontitis. This classification defines severe periodontitis and moderate periodontitis in terms of PD and CAL to enhance case definitions and further demonstrates the importance of thresholds of PD and CAL and the number of affected sites when determining prevalence.

Periodontal diseases

The periodontal diseases are highly prevalent and can affect up to 90% of the worldwide population. Gingivitis, the mildest form of periodontal disease, is caused by the bacterial biofilm (dental plaque) that accumulates on teeth adjacent to the gingiva (gums). However, gingivitis does not affect the underlying supporting structures of the teeth and is reversible. Periodontitis results in loss of connective tissue and bone support and is a major cause of tooth loss in adults. In addition to pathogenic microorganisms in the biofilm, genetic and environmental factors, especially tobacco use, contribute to the cause of these diseases. Genetic, dermatological, haematological, granulomatous, immunosuppressive, and neoplastic disorders can also have periodontal manifestations. Common forms of periodontal disease have been associated with adverse pregnancy outcomes, cardiovascular disease, stroke, pulmonary disease, and diabetes, but the causal relations have not been established. Prevention and treatment are aimed at controlling the bacterial biofilm and other risk factors, arresting progressive disease, and restoring lost tooth support.

Geometric alignment and chromatic calibration of serial radiographic images

OBJECTIVE

To develop software for automated registration and intensity calibration of serial dental radiographs for the analysis of longitudinal changes in bone density.

METHODS

Serial dental radiographs were acquired using a positioning device designed to minimize projection divergence. Each radiograph included an image of a standardized aluminium wedge. The radiographs were scanned on a flatbed scanner (AGFA Duo Scan) with a spatial resolution of 300 dpi, and pixel intensity coded in 16-bit grey scale. The intensity was calibrated using serial images of selected areas with defined thickness of the aluminium wedge. A robust B-splines multiresolution registration algorithm was implemented to overcome the acquisition misalignment. Radiographs, taken before and after periodontal therapy, were subtracted to assess bone density evolution.

RESULTS

The intensity calibration decreased the maximum intensity variations between serial radiographs from 30+/-17% to 1+/-1% (mean+/-standard deviation), and improved the visual comparison between the radiographs. The registration stage allowed correcting the misalignment of the radiographs on the scanner screen and superimposing the radiography contents. The observed residual motion was about 0.02+/-0.01 mm.

CONCLUSION

Very user-friendly software was developed. The manipulator needs to scan the radiographs only one time. The software performs all subsequent processing steps.

Periodontal ultrasonography

OBJECTIVES

The aim of this study was to investigate high-frequency ultrasound imaging for periodontal assessment.

MATERIAL AND METHODS

A newly developed ultrasonic scanner with a frequency of 20 MHz was used. Pig jaws were selected as the experimental model. Three teeth per jaw were imaged with the scanner and duplicate measurements were made of the distance from a fixed landmark on the teeth to the alveolar bone crest. These measurements were compared to transgingival and direct measurements of the same teeth following reflection of the soft tissues. One further jaw was used for histological comparison with the ultrasound image.

RESULTS

Using ultrasonography, it was possible to image the main periodontal structures. The ultrasound measurements showed better repeatability than either of the other two methods (repeatability coefficient: 0.44 mm for ultrasound, 0.93 mm for transgingival probing and 0.6 mm for direct measurements). Also, ultrasound was in better agreement with direct, open probing measurements (0.004 +/- 0.58 mm) than transgingival probing with direct measurements (0 +/- 0.7 mm).

CONCLUSIONS

Ultrasonography provides a highly accurate and repeatable technique for periodontal assessment in this model.

Gelatinase B is associated with peri-implant bone loss

The aim of this study was to clear whether gelatinase B is associated with peri-implant bone loss (PBL). Peri-implant sulcus fluid was collected from 46 implant sites in 12 patients. These sites were also characterized using modified Gingival Index (mGI). Activated and total gelatinase B levels, measured using a modified urokinase assay, showed correlation with PBL (n = 46, Spearman's rank correlation test). Activated and total gelatinase B values were significantly higher in PBL > 3 mm group (n = 6) compared to PBL < 1 mm (n = 29) and 1 < PBL < 3 mm (n = 11) groups (rank sum test). Activated gelatinase B level in mGI > 0.5 group (n = 24) was clearly higher compared to mGI = 0 (n = 13) and < or = 0.5 (n = 9) groups (Rank sum test). We conclude that gelatinase B is associated with PBL. Activation of gelatinase B together with elevated mGI eventually reflect active phases of peri-implantitis and may prove to be diagnostically useful.

Position Paper: Diagnosis of Periodontal Diseases

At the present time, the diagnosis and classification of periodontal diseases are almost entirely based on traditional clinical assessments. Supplemental quantitative and qualitative assessments of the gingival crevicular fluid and subgingival microflora can potentially provide useful information about the patient's periodontal disease. In certain situations, these supplemental risk-assessment tests may be particularly valuable in establishing the endpoint of therapy prior to placing patients on a periodontal maintenance program. Although the clinical utility of none of these tests has been validated, their further development is warranted. A genetic test for susceptibility to periodontitis has become commercially available. How best to use this and future host-based tests in clinical practice remains to be determined. Probing depth and clinical attachment loss measurements obtained with periodontal probes are practical and valid methods for assessing periodontal status. Computer-linked, controlled-force electronic periodontal probes are commercially available and are currently in use by some practitioners. Many of the logistical problems associated with subtraction radiography are being overcome and this powerful diagnostic tool may soon come into widespread use. Future developments in this and other imaging techniques are likely to have a profound effect on our approach to the diagnosis of periodontal diseases.

Accuracy of computer-assisted radiographic measurement of interproximal bone loss in vertical bone defects

Objective. The objective of the present study was to compare 2 different computer-assisted analysis systems with respect to the measurement of interproximal bone loss on radiographs. Study Design. In 14 patients with untreated advanced periodontal disease, 90 standardized radiographs were taken presurgically and during postoperative follow-up. During periodontal surgery for 30 vertical bone defects and 28 adjacent sites (22 vertical, 3 horizontal, and 3 without bone loss), the distances from the cementoenamel junction (CEJ) to the alveolar crest (AC) and from the CEJ to the bottom of bony defect (BD) were measured. In all radiographs, the linear distances from the CEJ to the AC and from the CEJ to BD were assessed by using 2 computer-assisted analysis devices: linear measurement (LMSRT) and FRIACOM (FRIADENT, Mannheim, Germany). A comparison between the radiographic and intrasurgical assessments was performed by using the paired t test. Results. With respect to the linear distance from the CEJ to the BD, the study failed to detect statistically significant differences between the computer-assisted techniques and intrasurgical measurement as the gold standard (LMSRT,: 0.26 +/- 2.16 mm [P >.05]; FRIACOM, 0.35 +/- 2.5 mm [P >.05]). In terms of the distance from the CEJ to the BD and from the CEJ to the AC, the correlation between both computer-assisted methods was excellent (r(s) > or = 0.75) and there were no statistically significant differences detectable between LMSRT and FRIACOM for both distances. With regard to the distance from the CEJ to the AC, both techniques overestimated interproximal bone loss as compared with intrasurgical measurements (CEJ-AC, LMSRT: 1.63 +/- 2.52 mm [P <.01]; FRIACOM: 2.00 +/- 2.48 mm [P <.01]). The amount of overestimation of interproximal bone loss did not differ significantly in either computer-assisted technique (P >.05). For double measurements, both LMSRT and FRIACOM showed excellent reproducibility with coefficients of variation that ranged between 3.8% and 4.5% (CEJ-BD) and between 5.7% and 6.6% (CEJ-AC). There were no statistically significant differences between the reproducibilities of both computer-assisted techniques (P <.05). Conclusions. Both LMSRT and FRIACOM are reproducible methods to measure the distances from the CEJ to the BD and from the CEJ to the AC on radiographs and can be recommended for clinical use. With respect to the distance from the CEJ to the AC, it must be kept in mind that both computer-assisted methods tend to overestimate the real distance on an average of 1.5 to 2.0 mm.

Periodontal risk assessment, diagnosis and treatment planning

The prevention and treatment of the periodontal diseases is based on accurate diagnosis, reduction or elimination of causative agents, risk management and correction of the harmful effects of disease. Prominent and confirmed risk factors or risk predictors for periodontitis in adults include smoking, diabetes, race, P. gingivalis, P. intermedia, low education, infrequent dental attendance and genetic influences. Several other specific periodontal bacteria, herpesviruses, increased age, male, sex, depression, race, traumatic occlusion and female osteoporosis in the presence of heavy dental calculus have been shown to be associated with loss of periodontal support and can be considered to be risk indicators of periodontitis. The presence of furcation involvement, tooth mobility, and a parafunctional habit without the use of a biteguard are associated with a poorer periodontal prognosis following periodontal therapy. An accurate diagnosis can only be made by a thorough evaluation of data that have been systematically collected by: 1) patient interview, 2) medical consultation as indicated, 3) clinical periodontal examination, 4) radiographic examination, and 5) laboratory tests as needed. Clinical signs of periodontal disease such as pocket depth, loss of clinical attachment and bone loss are cumulative measures of past disease. They do not provide the dentist with a current assessment of disease activity. In an attempt to improve the ability to predict future disease progression, several types of diagnostic tests have been studied, including host inflammatory products and mediators, enzymes, tissue breakdown products and subgingival temperature. In general, the usefulness of these tests for predicting future disease activity remains to be established in terms of sensitivity, specificity and predictive value. Although microbiological analysis of subgingival plaque is not necessary to diagnose and treat most patients with periodontitis, it is helpful when treating patients with unusual forms of periodontal disease such as early-onset, refractory and rapidly progressive disease. There appears to be a strong genetic component in some types of periodontal disease and genetic testing for disease susceptibility has potential for future use, but more research is needed to determine its utility for use in clinical practice. Treatment of the periodontal diseases may be divided into four phases: systemic, hygienic, corrective and maintenance or supportive periodontal therapy. Regardless of the type of treatment provided, periodontal therapy will fail or will be less effective in the absence of adequate supportive periodontal therapy.

Clinical application of a new compact computed tomography system for evaluating the outcome of regenerative therapy: a case report

BACKGROUND

The limitations of conventional 2-dimensional (2-D) radiographs have been emphasized in many studies. Because the image is a 2-D map of the 3-dimensional (3-D) tooth and periodontal tissue, these structures may be superimposed on each other. Recently, 3-D image analysis by computed tomography (CT) was introduced to dentistry, but it has been used only rarely in the periodontal field.

METHODS

The purpose of this case report was to introduce the clinical application of a newly developed, compact computed tomography system for evaluating the outcome of regenerative therapy in an adult patient with periodontitis (male, aged 55 years). To evaluate the bone defects including furcation involvement, we took an intraoral radiograph and performed CT scanning on tooth #19. We recorded a number of clinical parameters at the time of surgery. We compared the images of the bone defect obtained by CT images and the conventional radiograph with the true bone defect morphology at the surgical site.

RESULTS

One year after the periodontal surgery, we again took CT scans and a conventional radiograph, and the new images of the bone defect were compared and evaluated. The new CT images were reconstructed for 3-D evaluation and compared with those taken before surgery. The CT provides 3-D images of excellent quality for evaluating the morphology of the periodontal bone defect and furcation involvement.

CONCLUSIONS

We consider that CT is a useful aid in periodontal examination and diagnosis, and in the prediction and evaluation of periodontal treatment outcomes.

Collagenases in different categories of peri-implant vertical bone loss

The loosening of dental implants is associated with peri-implant vertical bone loss. The mechanisms and mediators of this bone destruction are not known. To test the hypothesis that collagenase-2 and collagenase-3 might be markers or maybe even mediators in this process, we measured collagenase-2 (time-resolved immunofluorometric assay) and collagenase-3 (quantitative immunoblot) in peri-implant sulcus fluid in 49 implant sites in 13 patients. Vertical bone loss was graded as being < 1 mm, from 1 to 3 mm, or > 3 mm. The severity of inflammation, as rated according to Gingival Index, did not correlate with the category of bone loss (p > 0.05). Collagenase-2 and collagenase-3 were higher (p < 0.05) in the group which had lost > 3 mm of bone than in the two other groups. Gingival Index is not a clinically important marker for bone loss, but collagenase-2 and collagenase-3 in peri-implant sulcus fluid are. They might participate in peri-implant osteolysis.

Analysis of sensitivity and specificity of a new digital subtraction system: an in vitro study

OBJECTIVE

The purpose of this study was to compare a new digital subtraction system with conventional radiograph images for the detection of periapical and periodontal bone lesions.

STUDY DESIGN

Periapical and periodontal bone lesions were simulated with cortical bone chips of varying sizes placed on a human dry mandible. Radiographic film images were acquired from varying projections and were subsequently digitized, registered, and subtracted. Four clinicians evaluated the subtracted images, and sensitivity and specificity were calculated.

RESULTS

The mean sensitivity and specificity of the Diagnostic Subtraction Radiography system for detecting bone lesions of all sizes with varying projection geometry were 87.90% and 85.23%, respectively. The corresponding results for conventional radiograph images were 47.54% and 97.38%. The difference in sensitivity was statistically significant, whereas the difference in specificity was not.

CONCLUSIONS

These results indicate that, even when radiographs are taken from disparate projection geometries, the Diagnostic Subtraction Radiography system is capable of excellent discrimination between healthy and disease states in this in vitro model.

The Accuracy of Radiographic Methods in Assessing the Outcome of Periodontal Regenerative Therapy

BACKGROUND

The study of regenerative therapy in the periodontal intrabony defect has relied upon surgical re-entry as the gold standard of outcome assessment. The search for a non-invasive method has led to the application of various radiographic techniques in evaluating post-treatment bone fill.

METHODS

The purpose of this study was to determine the ability of 2 forms of radiographic analyses (linear measurement and computer assisted densitometric image analysis, CADIA) to assess postsurgical bone fill as measured at a re-entry procedure. A method that incorporates linear measurements and CADIA (linear-CADIA) was developed and tested as well. Forty-five intrabony defects in 15 patients were treated with open flap debridement, demineralized freeze-dried bone allograft (DFDBA), or a combination of DFDBA and tetracycline. Standardized radiographs were obtained at baseline and at 1-year postsurgery.

RESULTS

A 12-month surgical re-entry provided clinical measurements for post-treatment bone fill. All radiographs were digitally scanned and analyzed on a computer. Fifty-three percent of the defects were excluded from the study due to poor standardization or poor defect quality. Forty percent of all pairs of radiographs were judged to have poor standardization. In the first analysis, standardized images were subtracted and quantitatively analyzed utilizing CADIA. It was found that CADIA had the highest correlation with clinical bone fill when a region of interest (ROI) was examined in the middle portion of the defect. This quantitative evaluation provided very little clinically relevant information regarding actual bone fill. For the second analysis, pre- and post-treatment linear radiographic measurements were obtained. In only 43% of the sites, did linear radiographic measurements determine post-treatment bone fill within 1.0 mm of the clinical measurements. Overall, linear measurements underestimated bone fill by 0.96 mm (+/-1.2). These differences were statistically significant (paired Student t-test, P = 0.0023). A method, which incorporates the use of both CADIA and linear radiographic measurements (linear-CADIA), was tested. The linear-CADIA method underestimated bone fill by 0.26 mm (+/-1.4), but these differences were not statistically significant (paired Student t-test, P = 0.41).

CONCLUSION

Linear radiographic measurements significantly underestimate post-treatment bone fill when compared to re-entry data. The linear-CADIA method provided the highest level of accuracy of the 3 methods tested. This study also emphasizes the importance of developing a consistent method of radiographic standardization.

Site-specific attachment level change detected by physical probing in untreated chronic adult periodontitis: review of studies 1982-1997

BACKGROUND

Site-specific attachment level change, detected from sequential physical probing measurements, is currently the most common method of determining the progression/regression or stability of disease status in subjects with chronic adult periodontitis. The sensitivity and accuracy of detection is dependent on the type of probe used, the recording method, the measurement error, and the method of data analysis. In recent years, there has been world-wide interest in developing instruments and methods to minimize measurement error. Published data report disturbingly wide variation in the prevalences and rates of site-specific attachment level change which are difficult to reconcile with biological likelihood. The present paper aims to summarize the salient points from the key studies and to compare the results.

METHODS

The literature between 1982 and 1997 was reviewed for studies in which site-specific attachment level change was detected by physical probing methods in patients with chronic adult periodontitis.

RESULTS

The review documents 23 studies by probe generation, compares methods and results and summarizes the results according to the thresholds and probe type used. The 23 studies used an array of probe types from the 3 probe generations.

CONCLUSIONS

From this review, we conclude that: 1) There are surprisingly few papers which have addressed the question of site-specific attachment level change in untreated chronic adult periodontitis. 2) There are considerable differences in the probes used, in the thresholds achieved, in the number of measurements taken, in the number of subjects and sites studied, and in the duration of the studies. Valid comparisons between studies are, therefore, rarely possible. 3) Only 8 out of 23 papers from 1982 to 1997 have adequate data. Most papers report only losing sites and therefore ignore many of the measurements recorded. Only one paper describes losing sites, gaining sites, and sites showing exacerbation/remission patterns of change. 4) The range of changes described show such variation that it has to be concluded that we cannot reliably detect site-specific attachment level change by physical probing and thus, at the end of the 20th century, we have no clear idea of the natural history of this disease.

Practical periodontal screening and diagnosis

The differences in approach between screening for and diagnosis of periodontal diseases are highlighted. The Periodontal Screening and Recording procedure is discussed in terms of its evolution and current application. For patients screened and found to have more advanced periodontal problems a panoramic dental radiograph with restricted supplemented periapicals are recommended. A comprehensive clinical periodontal examination should be performed for these patients, but it is argued that this may be performed after the initial hygiene phase of treatment. In establishing a diagnosis it is suggested that attention be paid to possible risk exposures. Newer, non-anatomic diagnostic procedures are discussed in principle and it is concluded that these do not have a practical application at present.