Radiographic evaluation of bone regeneration following periodontal surgery with or without expanded polytetrafluoroethylene barriers.

In 16 patients with advanced periodontitis, 23 teeth exhibiting interproximal intrabony defects were treated by conventional periodontal surgery (n = 10, control) or guided tissue regeneration (GTR) technique using expanded polytetrafluoroethylene (ePTFE) barriers (n = 13, test), respectively. Clinical parameters were assessed before and 6 months after surgery. Presurgically and 3 and 6 months postsurgically standardized bite-wing radiographs were taken. Using a loupe and a computer-assisted system, respectively, the distances from the cemento-enamel junction (CEJ) to alveolar crest (AC) and CEJ to the most apical extension of bony defect (BD) were measured. The average gain of attachment was assessed 2.33 mm in the control group and 3.17 mm in the test group. The bony fill was measured 0.97 mm and 0.97 mm in the control group and 0.93 mm and 1.68 mm in the test group after 3 and 6 months, respectively, using a loupe. Using a computer-assisted system 0.83 mm and 1.82 mm of bone fill could be measured (control) and 0.76 mm and 1.79 mm (test) after 3 and 6 months, respectively. Compared to the gold standard of surgical measurements, the computer-assisted analysis of radiographs underestimated bone loss significantly less than evaluation with a loupe (P < 0.002). Compared to conventional periodontal surgery, the GTR technique resulted in higher attachment gain and bony fill. However, the high variation of surgical results in the test group prevented the calculation of a statistically significant difference.

Periodontal surgery of vertical bony defects with or without synthetic bioabsorbable barriers. 12-month results.

The aim of the present study was to clinically and radiographically compare guided tissue regeneration (GTR) therapy with bioabsorbable polyglactin 910 barriers and conventional periodontal surgery in intrabony defects. In 26 patients with advanced periodontitis, 29 teeth exhibiting interproximal intrabony defects were treated; 15 by conventional periodontal surgery (control) and 14 by GTR (test). Before and 12 months after surgery, clinical parameters were assessed and standardized radiographs were taken. On the radiographs the distances from the cemento-enamel junction (CEJ) to the alveolar crest (AC), and the CEJ to the most apical extension of the bony defect (BD) were measured using a computer-assisted analyzing device (LMSRT). Twelve months after surgery, 24 patients with 27 lesions were available for examination. For both methods statistically significant (P < 0.001) probing depth (PD) reduction (mean +/- standard deviation) of -4.49 +/- 1.94 mm (n = 13, test) and -3.22 +/- 1.48 mm (n = 14, control), as well as clinical attachment gain (CAL-V) of 3.41 +/- 1.59 mm (test) and 2.07 +/- 1.10 mm (control), was observed. Radiographic changes of the distance CEJ to AC of -0.95 +/- 1.72 mm (n = 9, test), and -0.98 +/- 1.53 mm (n = 11, control) were not significant. A significant bony fill (distance CEJ-BD) of 1.05 +/- 1.22 mm was observed for the test group (P < 0.01); the 0.68 +/- 2.04 mm bony gain for the control group was not statistically significant. The PD reduction (P < 0.05) and attachment gain (P < 0.01) in the test group was statistically significantly more favorable than in the control group. Twelve months after surgery, statistically more favorable PD reduction and attachment gain was observed using polyglactin 910 barriers than compared to conventional flap surgery. Hence, the use of bioabsorbable barriers for therapy of intrabony defects may be recommended.

Digital radiographic measurement of approximal caries progression in fluoridated and non-fluoridated areas of Rio de Janeiro, Brazil.

The effect of fluoridation on approximal caries progression was investigated using serial digitized bitewing images and conventional film images of 290 12-16-year-old schoolchildren who were lifetime residents of either Rio de Janeiro (a fluoridated area) or Mangaratiba and Angra dos Reis (non-fluoridated areas) in the state of Rio de Janeiro, Brazil. One examiner scored a maximum of 28 approximal surfaces of posterior teeth per subject using both methods. The intraexaminer reliability for rating lesion depth with digital images was comparable with that of the conventional bitewing films (namely, intraclass correlation of 0.99 and weighted Kappa scores of 0.82, respectively). Approximal surface D1S was 3.17 +/- 0.25 (sx) in fluoridated areas and 6.64 +/- 0.44 in non-fluoridated areas. After 1 year, the rate of caries progression in approximal surfaces was significantly lower in the fluoridated areas (0.54 +/- 0.14) as compared with the non-fluoridated areas (1.41 +/- 0.20) using Pitts' scoring system for conventional bitewing radiographs (P < 0.001). Similarly, the digital radiographic method was able to detect subtle differences in approximal caries progression in the enamel and the dentin (overall mean: 0.34 mm/year in fluoridated areas vs 0.49 mm/year in non-fluoridated areas, P < 0.05). The two radiographic methods were strongly correlated (rs = 0.7). Assuming a constant rate over time, these results indicate that lesion progression from the outer half of the enamel into the outer half of the dentin takes approximately 3-4 years in schoolchildren from the fluoridated areas compared to 2 1/2 years in the non-fluoridated areas.

Comparison of a photostimulable phosphor system with film for dental radiology.

This study compared the imaging performance of a photostimulable phosphor system with E speed film for dental radiography. The response of each imaging system was measured as a function of radiation exposure. Measurements were also made of imaging performance in terms of the limiting spatial resolution and low contrast detectability. Photostimulable phosphors had a wider dynamic range in comparison with film. The limiting spatial resolution of the photostimulable phosphor was approximately 6.5 lp/mm and independent of image magnification. For film, the limiting spatial resolution was in the range 11 to 20 lp/mm depending on image magnification. At the same radiation exposure, low contrast detectability of the photostimulable phosphor was superior to that of film. Major benefits of photostimulable phosphor systems include the elimination of chemical processing and an improved low contrast detectability performance.

Validity of radiographic measurement of interproximal bone loss.

The aim of the present study was to compare radiographic assessment of interproximal bone loss using a loupe with a 0.1 mm calibrated grid and a computer-assisted analysis system (LMSRT). In 35 patients suffering from untreated advanced periodontal disease, 62 standardized radiographs were taken presurgically. The horizontal and vertical angulation difference of the central beam from the orthoradial projection was calculated for each radiograph. At the time of surgery, for 115 interproximal defects, the distances from the cementoenamel junction (CEJ) to alveolar crest (AC), and CEJ to bottom of the bony defect (BD) were measured. In all radiographs, the linear distances CEJ to AC, and CEJ to BD were assessed using a loupe and LMSRT. Comparison between radiographic and intrasurgical assessments was performed using paired t-tests. A stepwise multiple linear regression analysis was used to evaluate factors that influence the discrepancy between radiographic and intrasurgical measurements. Both analyzing techniques underestimated interproximal bone loss as compared with intrasurgical measurements (CEJ-AC: loupe: 0.86 +/- 1.84 mm [p < 0.001]; LMSRT: 0.58 +/- 1.86 mm [p < 0.005]; CEJ-BD: loupe: 1.22 +/- 2.33 mm [p < 0.001]; LMSRT: 0.80 +/- 2.09 mm [p < 0.001]). LMSRT underestimated interproximal bone loss significantly less than the loupe (p < 0.001). The difference between LMSRT and intrasurgical assessments was modulated by the factors of vertical and horizontal angulation difference and defect depth (p < 0.1). Orthoradial projection reduced underestimation of radiographic assessment of bone loss. LMSRT underestimated interproximal bone loss to a lesser extent than conventional evaluation by loupe.

Characteristics of an oral and maxillofacial radiology department. Report of the ad hoc Department Characteristics Committee of the American Academy of Oral and Maxillofacial Radiology.

Oral and maxillofacial radiology is a dynamic and multifaceted discipline that plays a critical role in patient care, the education of general dentists and dental specialists, and the academic health of the dental school. Diagnostic and treatment advances in temporomandibular joint disorders (TMD), implants trauma and orthognathic surgery, and craniofacial abnormalities depend heavily on conventional and advanced imaging techniques. Oral and maxillofacial radiology contributes to the education of pre- and post-doctoral dental students with respect to biomedical and clinical knowledge, cognitive and psychomotor skills, and the professional and ethical values necessary to properly prescribe, obtain, and interpret radiographs. The development of an active and successful oral and maxillofacial radiology department, division, or section requires the committment of institutional resources. This document may serve as a guide to dental schools committed to excellence in oral and maxillofacial radiology.

Diagnosis of caries progression from serial bitewings: a comparison between teachers and practitioners.

Approximal caries progression is best monitored from serial bitewing radiographs but the factors influencing dentists' interpretation of these films is poorly understood. Three radiographic tests were shown to a non-randomised group of 28 practitioners (GDPs) and 21 (predominantly part-time) teachers of conservative dentistry. Test 1 investigated an appreciation of the effects of irradiation geometry change on radiolucency depth. Test 2 detected evidence of irradiation geometry change from approximal overlaps and using this as a validity check for comparing serial films. Test 3 was designed to compare the effect of lack of radiolucency progression on the prescription of restorations. The results showed that in test 1, 43% of GDPs and 29% of teachers, despite being told of irradiation geometry changes, ignored the unreliability of the radiolucencies and recommended restorations. In test 2, 54% of GDPs and 71% of teachers ignored evidence of irradiation change. In test 3, 75% of GDPs and 76% of teachers ignored radiographic evidence of static carious lesions and prescribed restorations. Statistically there was no difference in the decision making outcomes between the two groups. There is cause for concern that objective radiographic data does not appear to be used correctly by the majority of dentists in planning treatment decisions.

Standardizing data collection and decision making with an expert system.

The software for the pilot system has been completed. The appropriateness of the risk factor weights needs to be evaluated by clinical testing. However, this does not prevent the system from being used to teach the philosophy of risk group identification and selection of different management strategies according to disease activity. The current system does demonstrate a dynamic relationship between caries risk assessment/activity and different management strategies. A formal scientific evaluation of the effectiveness of the system as a teaching tool is being developed.

Will modern caries management reduce restorations in dental practice?

Dentists have difficulty diagnosing caries presence and activity. Modern caries management suggests that lesions in low risk patients should not be restored until the radiolucency extends into the outer third of interproximal dentin. Even stained fissures need not be restored in the absence of occlusal dentin radiolucency. If this standard were adopted, what affect would it have on the amount of operative treatment delivered? This report created a model to forecast the change in work volume caused by new caries management strategies. The model considered two identical groups of 1,000 adult teeth with a normal distribution of 1,000 radiographic lesions in each group. Group I would have all lesions restored at baseline, but Group II would have only lesions in the dentin restored. Each year for ten years the model forecasts the number of replacement restorations for both groups, plus initial restorations for Group II. A sensitivity analysis was conducted using slow progression rates (Group IIa) and fast progression rates (Group IIb). After ten years, Group IIa has 49% and Group IIb had 32% fewer restorations than Group I. It is concluded that the model is robust and modern caries management may significantly reduce operative workload.

Practical approach to evidence-based management of caries.

This paper discusses evidence-based management of dental caries with regard to: (1) need to adopt new office methods, (2) potential barriers to change, and (3) possible practical solutions to aid change. The need for classifying individual patients into low-, medium-, and high-risk caries groups is justified from a review of the epidemiological characteristics of caries. In addition, a deficiency is identified in traditional caries recording methods since they are unable to grade the severity and activity of individual lesions. The traditional basis of six-monthly recall examinations for all patients is shown from the literature to have no scientific support. It is suggested a three-twelve month recall interval be used, depending on a patient's risk group classification. Some barriers to change are identified as: (1) the collection of more comprehensive history and clinical caries data, (2) the complexity of evidence-based decision-making, and (3) dentists' difficulty in standardizing decision-making. A new pictorial classification for caries severity and activity is described. A demonstration decision-support system is presented in terms of assisting collection of data, automatic identification of risk factors, patient risk classification, and generation of a suggested treatment plan. Evidence-based management may result in change of professional manpower levels.

Radiographic caries diagnosis and monitoring.

Radiography is still the best diagnostic technique which is widely available to dentists. Digital radiography offers improved imaging through lower dose and lack of chemical processing. However, monitoring of incipient caries progression requires imaging systems which are as good as film with testing at the D1 level (WHO). Care is required in constructing valid caries models. Work is required to define the necessary digital image quality as measurement accuracy for monitoring caries progression may be as high as 0.15 mm. A case has been made for using the highest sensitivity possible, since caries is a disease where a 'wait and see' policy should produce no unnecessary treatment from increased false positives. Individual site monitoring should be performed on both low and high caries risk patients. High-risk subjects still need to be monitored since DMFS is not a valid site level predictor.

Frequent, low-dose, improved-contrast radiographic images with the use of narrow x-ray beams.

Conventional dental radiography uses 60 mm-wide x-ray beams that irradiate the cheeks. To reduce the dose of radiation, months or years can separate serial films and prevent short-term assessment of disease activity. A technique that uses a 13 mm narrow x-ray beam that avoids the cheeks was compared with a wide x-ray beam by using a contrast phantom, a cheek substitute, and a serially sectioned dry mandible. Phantom contrast was measured densitometrically at 50 kVp, 65 kVp, and 90 kVp with wide x-ray beam and narrow x-ray beam and with and without cheek scatter. The narrow x-ray beam without cheek scatter technique resulted in better contrast (0.06 to 0.04 OD) than the wide x-ray beam with cheek scatter (0.05 to 0.02 OD). A posterior interdental crest was irradiated and a trabecular rod was removed. The bone detail was best in the images produced with the narrow x-ray beam without cheek scatter. The area of the narrow x-ray beam was 4.35% of the area of the wide x-ray beam with approximately 5% of the dose. Short-interval (weekly), very-low-dose radiography should be possible with improved contrast to assess alveolar bone changes.

A computer-assisted method for making linear radiographic measurements using stored regions of interest.

Accurate detection of changes in alveolar bone height requires radiographic measuring methods with a reliability of standard deviation (SD) of 0.15 mm or better. No periodontal digital imaging system has reached this reliability, although 3 analogue methods have achieved this goal. However, existing linear methods are time-consuming, difficult to use, unsuitable for measuring all possible (unsharp) anatomical sites and do not provide a confidence estimate for sites of change observed in serial standardized films. A rapid computer-assisted method using stored image regions of interest (ROI) has been developed which allows retest measurements for all possible sites and automatically calculates a 90%, 95%, 98%, or 99% confidence threshold value, derived from duplicate measurement variation, for sites of apparent crest height change. 28 examiners, with minimal training in operating the system, measured 14 different cement-enamel junction to crest height distances from a standard bitewing image, with and without the ROI method. The measurements were repeated 4 weeks later. 13/14 sites achieved an intra-examiner SD threshold of less than or equal to 0.15 mm with the ROI method but 0/14 without. A higher inter-examiner SD threshold of less than or equal to 0.22 mm was achieved for 13/14 sites using ROI and 0/14 without (p less than 0.001). The measurement of crest height changes in a region of previous severe vertical bone loss is demonstrated using serial films. The potential for using trabecular bone patterns as reference sites in regions where traditional measurement points are absent is demonstrated.(ABSTRACT TRUNCATED AT 250 WORDS)