Students' attitudes to digital radiography and measurement accuracy of two digital systems in connection with root canal treatment

The aim of this study was to evaluate students' attitudes towards digital radiography and measurement accuracy in digital images recorded with a CCD-sensor and a photostimulable phosphor (PSP) plate radiography system in connection with root canal treatment. Thirty-one dental students participated in an endodontic course. Two single-rooted teeth were assigned at random to two receptors for digital radiographic examination, either (i) the RVG-ui CCD sensor or (ii) the Digora PSP plate system. After the endodontic treatment had been completed for the first tooth, the student filled in a questionnaire on their use of the digital system. Thereafter, the students switched radiography system and repeated the procedure for the second tooth. Eventually, the students completed the questionnaire by answering questions that directly compared the two digital systems. The gutta-percha filled tooth was measured using the system's own software. Two measurements of each tooth were performed: total tooth length (TTL) and root filling length (RFL). The teeth were dismounted from the plaster blocks and the true TTL and RFL was measured with an electronic slide calliper. The majority of the students had used the contrast enhancement facility (CCD sensor = 52%, PSP = 71%) and the zoom facility (65-68%) whilst some had used the density enhancement facility (CCD sensor = 39%, PSP = 55%). The students stated that they saved more time when they used the CCD sensor than when they used the PSP system (P < 0.001), and that it was easier to position the tooth with the PSP plate than with the sensor (P < 0.01). The lengths measured on the digital images from both digital systems were marginally larger than the true tooth lengths (P < 0.05). However, there was no difference between the two digital systems for the TTL/RFL ratio (P > 0.05).

Bitewing and digital bitewing radiography for detection of caries lesions

When radiography is applied in the clinic for caries detection, the recommended technique is bitewing projection (Gröndahl, 1994). This technique was introduced by Raper (1925) and has continued with only minor alterations. The aims of this report are to provide evidence for (1) optimal bitewing recording for individual examinations and clinical trials, (2) advantages and disadvantages of digital receptors for bitewing examinations, (3) the diagnostic outcomes and limitations of bitewing radiography, and (4) computer-automated detection of caries.

Comparison of standard and task-specific enhancement of Digora storage phosphor images for approximal caries diagnosis

OBJECTIVES

To compare approximal caries detection on Digora storage phosphor images pre-enhanced with the automatic "caries-specific Oslo enhancement procedure" ("Oslo-enhanced" method) and storage phosphor images individually enhanced by observers particularly experienced in digital imaging using standard brightness and contrast functions of the Digora system ("Digora-enhanced" method).

METHODS

Seven staff members from four oral radiology departments rated 240 approximal surfaces for caries with regard to lesion depth in the inner and outer half of the enamel and dentine, using a 5-point confidence scale. The observations were validated histologically. A receiver operating characteristic (ROC) analysis and an analysis of variance with three dependent variables (observer confidence, observer signed error and observer absolute error) were performed.

RESULTS

The most evident difference between the methods as elucidated by the ROC analysis was the highly significant smaller interobserver and intraobserver variance with the Oslo-enhanced method for all but one observer. The methods were not different with regard to average diagnostic accuracy (A(z) values) as tested with paired t-tests, and there was no correlation between A(z) across methods. The method and lesion main effects, as well as the lesion by method interaction effect, were multivariately significant (P<0.001) in favour of the Oslo-enhanced method. On a univariate level, the method main effect was not significant for the absolute observer error (P=0.330). All other univariate effects were significant (P<0.001).

CONCLUSIONS

The accuracy of approximal caries detection with Digora storage phosphor images pre-enhanced and images individually enhanced was similar, but interobserver and intraobserver variability improved with the Oslo-enhanced method. Since image manipulation is not performed with the Oslo-enhanced method, the increased speed of the diagnostic procedure combined with the improved observer variability would probably be even more pronounced for the general dental practitioner.

Bitewing examination with four digital receptors

OBJECTIVES

To evaluate recording errors and patient discomfort during bitewing examinations using four digital receptors.

METHODS

Seventy-eight patients had two bitewings taken on each side of the mouth with the intention of displaying the tooth surfaces from the distal surface of the canine to the distal surface of the most posterior molar, using four digital receptors, two charge-coupled device (CCD) and two photostimulable phosphor (PSP) systems. The patients scored their feelings of discomfort during the examination on a visual analogue scale. Receptor positioning errors in the sagittal plane were determined from the tooth surfaces present on each image and in the vertical plane from the presence of the alveolar bone crest. Cone positioning errors were determined from cone cuts.

RESULTS

Canine and premolar surfaces were more often not depicted on the CCD images than on the PSP images (P<0.05). Cone cuts occurred in 19% of DenOptix images, in 9% of Digora images and in one Planmeca image. The bone crest was more often missing in the upper jaw on Planmeca images than on PSP images (P<0.01). In the lower jaw, Trophy images more often missed the bone crest than the other systems (P<0.05). Patients ranked the receptors as follows (with increasing discomfort): DenOptix, Planmeca, Digora and Trophy, with all being significantly different (P<0.05).

CONCLUSIONS

It was more difficult to correctly position CCD sensors than PSP plates in the vertical plane, resulting in more images with missing alveolar bone crest. CCD sensors most often did not display the most anterior surfaces in a bitewing examination.

Integration of multiple direct digital imaging sources in a picture archiving and communication system (PACS)

OBJECTIVES

The aim of this report was to describe a flexible picture archiving and communication system (PACS) able to handle and communicate digital image data from various radiography systems and other sources.

METHODS

The radiographic image is acquired using the vendor's own software. Following image capture, a "request for update" message (appending a record to an Access database) activates our PACS engine, "DigiMerge". Images from sources with no patient-related organizing software, e.g. TWAIN-compatible scanners and digital cameras, are handled by a self-developed program, "MedCom-T". DigiMerge generates and maintains one database based on all manufacturers' databases (software: VixWin 2000, Digora for Windows, Dimaxis Pro, Sidexis, CDR DICOM for Windows, Trophy for Windows). This database contains patient information, image information and image path. The program "DigiView" searches a patient and displays patient and image data from the database generated by DigiMerge. With DigiView, images can be viewed at any workstation in the dental school, but only temporary changes can be made (contrast, brightness, etc.) and no image can be deleted.

RESULTS

The PACS is currently installed on 86 workstations. Statistics collected by DigiMerge reveal that approximately 2000 new digital images are recorded each month, half of which are radiographs and the other half are clinical photographs. Statistics collected by DigiView reveal that 500-800 digital images are opened per week.

CONCLUSIONS

The self-developed PACS is able to manage images from a range of digital modalities each providing its own image data format.

Genetic programming approach for the optimal selection of combinations of neuronal networks to classify sleep stages by QUISI

The usefulness of a new way to optimize the cooperation of trained neural networks for automatic one-channel sleep stage analysis using genetic programming and performance evaluation by including the interrater reliability are the focus of our paper. The one-channel sleep classification could be significantly improved by the optimization. The software tool HENNE, with its genetic programming compartment was developed for this purpose. The tool has proved to be useful for searching for optima in difficult goal surfaces. To contribute to the general discussion about the benefit of the automatic one-channel sleep analysis on the basis of the frontal site, we tried to evaluate our results before the background of the interrater variability. Comparing the kappa statistics of different independent studies with our results, we concluded that there are no dramatic differences as a rule and that QUISI is a useful device as a presleep laboratory and ambulatory diagnostic tool.

Increased light damage susceptibility at night does not correlate with RPE65 levels and rhodopsin regeneration in rats

The susceptibility of rats to light-induced retinal degeneration is increased at night. In mice, an important determinant of light damage susceptibility is the efficacy of rhodopsin regeneration after bleaching. The rate of rhodopsin regeneration is at least partly controlled by RPE65, a protein expressed in the retinal pigment epithelium. We therefore tested a potential involvement of RPE65 and rhodopsin regeneration in the increased light damage susceptibility of rats at night. For this purpose, rats were exposed to visible light at noon or at midnight and extent of light damage was determined by retinal morphology and TUNEL staining. Rpe65 gene expression was analyzed by semiquantitative RT-PCR and levels of RPE65 protein were determined by Western blotting. Rhodopsin regeneration kinetics was determined by measuring rhodopsin content immediately after a strong bleach and after different times of recovery in darkness. Rats were more susceptible to light damage at night as described by Organisciak and collegues [Invest. Ophthalmol. Vis. Sci. 41 (2000) 3694]. Rpe65 gene expression followed a day-night rhythm with highest steady-state mRNA levels at the beginning and lowest levels at the end of the day period. However, RPE65 protein levels remained constant. Rhodopsin regeneration kinetics did not differ during day and night. We conclude that levels of RPE65 protein and rhodopsin regeneration kinetics do not correlate with the increased light damage susceptibility observed in rats at night. Additional genetic or physiologic modifiers may exist in rats that regulate the retinal responsiveness to acute light exposure.

Electrocardiographic signs of hypertrophy in fabry disease-associated hypertrophic cardiomyopathy

AIMS

Fabry disease results from deficient activity of the lysosomal enzyme alpha-galactosidase A. Progressive accumulation of the major substrates leads, in both men and women, to progressive hypertrophic cardiomyopathy. We aimed to evaluate the utility of different electrocardiographic (ECG) parameters for assessing the degree and severity of hypertrophic cardiomyopathy in patients with Fabry disease.

METHODS

A total of 166 ECGs of 94 hemi- and heterozygous patients with Fabry disease were analysed and compared with echocardiographic-estimated left ventricular mass (LVM).

RESULTS

There was a significant (p < 0.0001) correlation between QRS duration (R2 = 0.59), 12-lead amplitude/duration product (R2 = 0.61), Sokolow-Lyon voltage/duration product (R2 = 0.52) and LVM. Analysis of receiver operating characteristics revealed that the 12-lead amplitude/duration product had the highest sensitivity-specificity relationship (p < 0.01 compared with the Cornell index).

CONCLUSION

In general, ECG signs of left ventricular hypertrophy correlated well with LVM as revealed by echocardiography. Of the parameters studied, the 12-lead amplitude/duration product was the most successful at describing the severity of cardiac involvement in Fabry disease. These data suggest that ECG parameters have potential for use as a simple and cost-effective means of screening for hypertrophic cardiomyopathy in patients with Fabry disease.

[Improving signal-noise relations of evoked potentials by neural networks]

Single trial evoked potentials recorded in a sleep deprivation experiment were analyzed by means of neural networks. For improving the signal-noise-ratio a neural network classifier was trained to distinguish between the S-class which consists of assumed visually evoked single trial potentials and the N-class which should contain no event related components. The members of S-class and the N-class were averaged separately. We compared the averaged potentials of all single trials with the averaged potentials of the S-class members and we were able to show a significant improvement in the amplitudes and the signal-noise-ratio. We got the result that increasing sleep deprivation corresponds to a significantly decreasing number of members in the S-class. We concluded that sleep deprivation led to a significant number of stimuli which could not be preprocessed.

Identification of endocrine-disrupting effects in aquatic vertebrates and invertebrates: report from the European IDEA project

The EU-funded project IDEA aimed to evaluate (a) what parameters and endpoints allow the detection of endocrine-mediated developmental and reproductive effects of (xeno)estrogens in life cycle- and life stage-specific toxicity tests with the zebrafish Danio rerio, a small laboratory fish used in many ecotoxicity test guidelines, and (b) whether substances that act as estrogens in vertebrates may also adversely affect the development, differentiation, and reproduction of aquatic invertebrates. The invertebrate species investigated included Hydra vulgaris, Gammarus pulex, Chironomus riparius, Hyalella azteca, and Lymnaea stagnalis. The animals were exposed to the model estrogenic chemicals ethynylestradiol (EE2), bisphenol A (BPA), and octylphenol (OP), which exert their endocrine activity in vertebrates through the estrogen receptor. As endpoints, developmental and reproductive parameters at the organism level as well as molecular and cellular parameters were measured. Life cycle exposure of zebrafish to (xeno)estrogens induced a specific, partly irreversible response pattern, consisting mainly of (a) induction of vitellogenin (VTG), (b) alterations of gonad differentiation, (c) delay of first spawning, and (d) reduced fertilization success. The effects of EE2 on zebrafish were expressed at environmentally realistic concentrations, while BPA and OP became effective at concentrations higher than those usually found in the environment. The vitellogenic response was equally sensitive as the reproductive parameters in the case of EE2, but VTG was more sensitive in the case of BPA. Partial life cycle exposure of zebrafish had lasting effects on fish development and reproduction only when the fish were exposed during the stage of juvenile bisexual gonad differentiation. In (partial) life cycle and multigeneration studies with invertebrates, (xeno)estrogenic impact was assessed by a range of developmental and reproductive parameters including hatching, growth, moulting, mating behavior, and egg number. Several parameters were found to be responsive to (xeno)estrogens; however, most effects were induced only at higher, probably nonphysiological concentrations. Low-dose effects were observed in full life cycle experiments, particularly in the second generation. It remains to be established whether the estrogen-induced alterations in the invertebrate species indeed do result from disturbances of the endocrine system. The findings of the present research project support the development of appropriate testing methodologies for substances with estrogenic activity.

Accuracy of digital and film panoramic radiographs for assessment of position and morphology of mandibular third molars and prevalence of dental anomalies and pathologies

OBJECTIVES

To compare the accuracy of digital and film panoramic radiographs for determining (1) the position and morphology of mandibular third molars before surgical removal and (2) the prevalence of dental anomalies and pathologies.

METHODS

Three hundred and eighty-eight third mandibular molars were available for examination. Position and morphology of third molars observed on film radiographs and on digital panoramic images from five systems (DenOptix, DigiDent, Digora, Dimax2 and Orthophos Plus) were recorded by two observers and were compared with surgeons' findings at the time of the operation (gold standard). One observer further recorded the prevalence of dental anomalies and pathologies on both imaging modalities.

RESULTS

Few differences were found between the digital and film-based panoramic systems in the assessment of accuracy of position and morphology of mandibular third molars. The prevalence of dental anomalies and pathologies determined with the two modalities was roughly similar.

CONCLUSION

The five digital panoramic systems evaluated in this study were equally as useful for third molar treatment planning and diagnosis of dental anomalies and pathologies as conventional film-based panoramic radiographs.

Potencies of estrogenic compounds in in vitro screening assays and in life cycle tests with zebrafish in vivo

The objective of this study was to compare the estrogenic potency of environmental estrogens at two testing tiers: at the initial level of in vitro screening assays, and at the level of definitive fish reproduction tests in vivo. The in vitro tests included a recombinant yeast estrogen receptor (ER) assay, a competitive radioreceptor assay using the hepatic ER of carp (Cyprinus carpio), and assays on vitellogenin induction in cultured hepatocytes of rainbow trout (Oncorhynchus mykiss) and carp. In vivo, full life cycle tests with zebrafish (Danio rerio) were performed, using fertilization success as estrogen-sensitive reproductive endpoint. The test compounds included the natural estrogen 17beta-estradiol (E2) (only applied in the in vitro assays); the synthetic estrogen ethynylestradiol (EE2); and two xenoestrogens, 4-tert-octylphenol (OP) and bisphenol A (BPA). Among the in vitro assays, differences were observed in the relative ranking of the test substances, and in the absolute sensitivity (EC50 values), although the interassay differences of EC50 values were within one order of magnitude. The in vivo activity of the test compounds was not accurately predicted by the in vitro assays, with respect to neither sensitivity nor ranking. The in vitro assays tended to overestimate the relative potency of the xenoestrogens; i.e. the ratio between the activity of the reference compound, EE2, and that of the test compound. The best prediction of the in vivo fish test results was obtained from the recombinant yeast assay.

Prevalence of generalized anxiety at eight weeks postpartum

OBJECTIVE

This study investigated the prevalence and nature of generalized anxiety symptoms in women who were eight weeks postpartum.

METHOD

A community-based sample of 68 postpartum women completed an interview assessing generalized anxiety disorder and depression and a self-report measure of worry associated with concerns relevant to postpartum women.

RESULTS

Three women (4.4%) met DSM-IV criteria for generalized anxiety disorder, and an additional 19 women (27.9%) endorsed subsyndromal difficulties with generalized anxiety. Approximately one third of these women endorsed symptoms of depression. In contrast, only two woman met criteria for major depressive disorder.

CONCLUSION

Postpartum generalized anxiety has a higher prevalence than postpartum depression.

Why study rod cell death in retinal degenerations and how?

Age-related macular degeneration (AMD) is a main causes of severe visual impairment in the elderly in industrialized countries. The pathogenesis of this complex diseases is largely unknown, even though clinical characteristics and histopathology are well described. Because several aging changes are identical to those observed in AMD, there appears to exist an unknown switch mechanism from normal ageing to disease. Recent anatomical studies using elegant innovative techniques reveal that there is a 30% rod loss in normal ageing, which is increased in early AMD. Those and other observations by Curcio and co-workers indicate that early rod loss is an important denominator of AMD (Curcio CA. Eye 2001; 15:376). As in retinitis pigmentosa (RP), rods appear to die by apoptosis. Thus it seems mandatory to study the regulation of rod cell death in animal models to unravel possible mechanisms of rod loss in AMD. Our laboratory investigates signal transduction pathways and gene regulation of rod death in our model of light-induced apoptosis. The transcription factor AP1 is essential, whereas other classical pro- and antiapoptotic genes appear to be less important in our model system. Caspase-1 gene expression is distinctly upregulated after light exposure and there are several factors which completely protect against light-induced cell death, such as the anesthetic halothane, dexamethasone and the absence of bleachable rhodopsin during light exposure. A fast rhodopsin regeneration rate increased damage susceptibility. Our data indicate that rhodopsin is essential for the initiation of light-induced rod loss. Following photon absorption, there may be the generation of photochemically active molecules wich then induce the apoptotic death cascade.

Image quality of two solid-state and three photostimulable phosphor plate digital panoramic systems, and treatment planning of mandibular third molar removal

OBJECTIVES

The purpose was to evaluate image quality of two solid-state (charge-coupled device (CCD)) and three photostimulable phosphor (PSP) plate digital panoramic systems, and to assess their utility for treatment planning before mandibular third molar removal.

METHODS

433 patients were randomly allocated to five digital systems: Dimax2 and Orthophos Plus (both CCD systems) and DenOptix, DigiDent and Digora (all PSP systems). Image quality was evaluated in six regions on a 4-point scale by three independent observers. In addition, an oral surgeon evaluated image quality in the mandibular third molar region only as well as the utility of the image for treatment planning before removal of that molar.

RESULTS

Images from the DenOptix and DigiDent systems had a significantly lower overall quality than images from the Digora, Dimax2 and Orthophos Plus systems (P < 0.005). The oral surgeon's assessment of image utility resulted in rejection rates of 0% for Orthophos Plus, 2% for Digora, 8% for Dimax2, 12% for DigiDent and 14% for DenOptix images. The rates for the DigiDent and DenOptix images were significantly higher than those for the other systems (P < 0.001), and the rate for Dimax2 was significantly higher than that for Orthophos Plus (P = 0.002).

CONCLUSIONS

The quality of DenOptix and DigiDent digital panoramic images was found to be inferior to the quality found in images obtained with the Digora, Dimax2 and Orthophos Plus systems. Images from the Digora and Orthophos Plus systems were regarded to be the most useful for treatment planning before mandibular third molar removal.

Light damage susceptibility and RPE65 in rats

A sequence variation in the pigment epithelial protein RPE65 has been shown to correlate with RPE65 protein levels, rhodopsin regeneration kinetics and light damage susceptibility in different mouse strains. Here, we tested whether such a correlation can also be found in rats. We examined four rat strains for RPE65 protein levels and the Rpe65 gene sequence. In two strains, we additionally determined Rpe65 mRNA levels, rhodopsin regeneration and light damage susceptibility (LDS).RPE65 protein levels were higher in Lewis and Brown Norway rats compared to Wistar and Long Evans. The albino strains Wistar and Lewis were investigated further. Lewis had higher Rpe65 mRNA levels than Wistar. Sequence analysis of the coding region of the Rpe65 cDNA revealed no relevant sequence variations in the two strains. Content and regeneration of rhodopsin were comparable in both strains. However, Wistar rats were more susceptible to light damage than Lewis. We conclude that lower RPE65 protein levels in Wistar may have been caused by decreased gene expression and not by a sequence variation as suggested for mice. In rats, RPE65 may not be a limiting factor for rhodopsin regeneration. Since LDS in rats did not directly correlate with RPE65 protein levels and rhodopsin regeneration, other yet unidentified (genetic) factors may account for the susceptibility differences observed in rats.

[Transcatheter occlusion of the persisting arterial duct]

BACKGROUND

Transcatheter occlusion of the persisting arterial duct (PDA) is feasible using different techniques like coil-embolization (CE), Rashkind PDA occluder (Rash), Amplatzer Duct Occluder (ADO). Comparative studies with this devices in relation to the size of the PDA and the device are missing. Aim of this study was to evaluate the different systems at the own patient population.

PATIENTS AND METHODS

From 1993 to 12/2001 transcatheter occlusion was attempted in 92 patients aged 4,13 years (range 0,07 to 14,39 years) using CE, Rash or ADO. All patients received echocardiographic examinations 24 hours before and after intervention, after 3, 6, and 12 months and than yearly.

RESULTS

91/92 PDAs could be successfully closed by 97 interventions. There were 63 CE, 25 Rash and 9 ADO performed. Primary closure rate was 75 % for Rash, 80 % for ADO and 80,8 % for CE (n. s.) and after 6 months 88 % for Rash, 92,3 % for CE and 100 % for ADO (p < 0,001), although the size of the PDA increased significantly from CE (2,14 + 1,1 min) to Rash (3,2 +/- 1,3 min) to ADO (4,9 +/- 1,9 min) (p < 0.05). In 6/7 pts with residual shunts complete occlusion could be achieved by second intervention.

CONCLUSION

In dependency of the size of the PDA and the right choice of the occluder almost all PDAs are closable with transcatheter techniques.

Guided tissue regeneration in intrabony defects using an experimental bioresorbable polydioxanon (PDS) membrane. A 24-month split-mouth study

AIM

The comparison of the clinical, radiographic, and microbiological healing results in deep intrabony defects following GTR therapy with two different bioresorbable membranes in a prospective split-mouth design.

MATERIAL AND METHODS

31 pairs of contralateral intrabony defects were randomly treated with either an experimental Polydioxanon (PDS) membrane or a Polylactic acid (PLA) matrix barrier. After 6, 12 and 24 months, healing results were assessed using clinical examinations (REC, PPD, CAL, vertical relative attachment gain V-rAG), quantitative digital subtraction radiography (amount and area of bone density changes), and microbiological analysis.

RESULTS

Postoperative membrane exposures occurred in 14 PDS and 2 PLA treated sites. 6, 12 and 24 months p.o., both membranes provided a significant gain in CAL [median values: 6 months (PDS vs. PLA: 3.0 vs. 3.0 mm); 12 and 24 months (PDS vs. PLA: 4.0 vs. 4.0 mm)], which corresponded to a V-rAG of 57.1% (PDS) vs. 62.5% (PLA) after 24 months. PDS and PLA treated sites revealed significant bone density gain 6, 12 and 24 months after surgery. 38.8% (PDS) vs. 41.8% (PLA) of the initial defect areas showed bone density gain. While the gain in bone density was significantly greater in PDS than in PLA sites, neither CAL gain nor the area of bone density changes revealed significant differences. Microbiological culture revealed similar bacterial loads in PDS and PLA sites during the first 12 months.

CONCLUSION

This 24-month study indicates that the PDS and PLA membranes can provide similar favorable regeneration results in deep intrabony periodontal defects, although considerably more postoperative membrane exposures have to be expected in PDS treated sites.

Accuracy of caries detection with four storage phosphor systems and E-speed radiographs

OBJECTIVE

To evaluate the accuracy of caries detection using four intra-oral storage phosphor plate systems exposed with two different exposure times and one film system.

METHODS

Under in vitro and standardised conditions 365 approximal and 159 occlusal surfaces were radiographed using four storage phosphor plate systems: DenOptix, Cd-dent, Digora (blue and white plates) and one film system: Ektaspeed Plus. The plates were exposed twice with 10% and 25% of the time needed for the film. Four observers recorded approximal enamel/dentine and occlusal dentine caries using a five-point confidence scale. Caries presence was validated histologically and diagnostic accuracy of the systems by using ROC curve areas (Az).

RESULTS

The shorter exposure time for approximal caries, Digora(white)(Az=0.68) and Ekta Plus (Az=0.69) were significantly more accurate than the other systems (Az=0.64-0.65). For occlusal caries using the same exposure time, no significant difference was found between the digital systems (Az=0.76-0.77), which all showed to be significantly less accurate than Ekta Plus (Az=0.81). Using the longer exposure time for approximal caries, no significant difference was found between DenOptix (Az=0.68), Digora(blue) (Az=0.69), Digora(white) (Az=0.69) and Ekta Plus (Az=0.69) which were all significantly more accurate than Cd-dent (Az=0.65). For occlusal caries using the same exposure time, Digora(blue) (Az=0.81) was the most significantly accurate of the digital systems. When approximal caries was the diagnostic task, the longer exposure time resulted in significantly higher accuracy with the DenOptix and Digora(blue) systems but not with the Cd-dent and Digora(white) systems. For occlusal caries, the longer exposure time resulted in a significant improvement only with the Digora(blue) system.

CONCLUSION

For approximal caries using the longer exposure time, no significant difference in diagnostic accuracy was found between DenOptix, Digora(blue), Digora(white) and Ekta Plus which were all significantly more accurate than the Cd-dent. For occlusal caries using the longer exposure time, Digora(blue) was found to be the most accurate of the digital systems. The exposure time had an influence on the diagnostic accuracy with the DenOptix and Digora(blue) systems for approximal and with the Digora(blue) system for occlusal caries detection.

Evaluation of effect of 3D video glasses on perceived pain and unpleasantness induced by restorative dental treatment

Previous studies on modulation of anxiety, pain and unpleasantness have documented a positive effect of video glasses (I-Glasses, Virtual i-O, Seattle, USA) on the perceived pain and unpleasantness under different laboratory and clinical conditions. The aim of this study was to evaluate whether distraction induced by video glasses also had an effect on the perceived intensity of pain and unpleasantness during dental treatment. Pain and unpleasantness was evoked by the preparation (drilling) of a minor dental cavity (class I). Twenty-three patients (17 female and six male, age range 20-49 years) with a need for an occlusal dental restoration in two homologous teeth participated in the study. In this split-mouth design, the patient received the dental treatment wearing 3D video glasses and without video glasses (control situation) in a randomized order. The tooth cavities were prepared in accordance with conventional techniques after mounting the video glasses. The patient rated the intensity of pain and unpleasantness on 100 mm visual analogue scales (VASs) after preparation of the first cavity; immediately after, the opposite tooth was prepared and again the volunteer rated the intensity of pain and unpleasantness. The cavities were then filled using a routine composite technique. Eventually, the patient indicated whether she would prefer video glasses or not if she were to have another filling and what the expectations of the effect had been. Differences in VAS ratings in the video and control situation were tested by Student's t-test. There was no statistically significant effect on the perceived pain (p=0.90) or unpleasantness (p=0.39), but the majority (74%) of the patients would still prefer to wear video glasses if they were to have another dental filling, and 73% had expected a positive effect of the video glasses. These findings suggest that perceived intensity of dental pain is resistant to a simple distraction technique.