E.H. Verdonschot

Marginal integrity and postoperative sensitivity in Class 2 resin composite restorations in vivo

INTRODUCTION Problems that may arise in resin composite Class 2 restorations include microleakage and postoperative sensitivity. However, limited in-vivo research is conducted to evaluate these processes. AIM The aim of this study was to assess postoperative sensitivity, microleakage and the pooling of adhesives in relation to Class 2 box-type composite restorations placed in vivo using various adhesive systems and application techniques. MATERIALS AND METHODS One hundred and forty-four Class 2 box restorations were placed in the mesial and distal surfaces of 72 premolar teeth in-vivo using one of three combinations of adhesive systems and three filling techniques. After 6 weeks of clinical service postoperative sensitivity was recorded. The teeth were then extracted, immersed in a dye solution and sectioned. Microleakage and pooling of the adhesive was recorded. Statistical analysis involved logistic regression and chi2 tests to identify differences between groups at p < 0.05. RESULTS Of the 144 restorations, 65 showed minimal cervical leakage in enamel, 5 suffered leakage into dentin and 74 were free of microleakage. No statistically significant differences were found in cervical microleakage between the adhesive systems or between filling procedures. Occlusal microleakage in the enamel was present in 16 of the 160 restorations. Liner Bond 2 restorations leaked significantly more at the occlusal surface (p < 0.05). Pooling of the adhesive was significantly less when PhotoBond was used. No spontaneous postoperative sensitivity was reported. Twenty-eight restorations were sensitive to loading. Postoperative sensitivity was significantly less in patients with Liner Bond 2 restorations. CONCLUSIONS The adhesive systems used in this study showed minimal leakage into dentin in vivo. Using Liner Bond 2, restorations exhibited more occlusal leakage but were significantly less sensitive to loading.

Developments in radiographic caries diagnosis

The developments that have been taking place in radiographic caries diagnosis, within the context of the changes occurring in both the disease process and the available technology, are reviewed. The decline in caries prevalence seen in many western countries has been accompanied by changes in the pattern and behaviour of lesions. More lesions are now seen on occlusal surfaces, more are concealed (and thus imperceptible to conventional diagnostic techniques), while the average progression rates for approximal lesions have also slowed. Systems employed for caries diagnosis must take account of these changes and the varying needs of users employing different diagnostic thresholds. This paper reviews and discusses developments in: conventional film radiography; xeroradiography; indirect digital imaging (with computer image analysis and subtraction radiography), and direct digital imaging. It is concluded that: for the detection in high caries prevalence groups of both approximal caries (especially small lesions in enamel) and dentinal occlusal lesions in teeth with little or no surface breakdown, radiography is still a significant and reasonably accurate diagnostic method; and that, in spite of the more limited resolution, digital imaging methods seem to perform as well or better than conventional film radiography. Digital systems possess a number of advantages, primarily the possibility for image enhancement and significant dose reduction. It may be predicted that digital imaging techniques will enter the clinical routine in the near future.

Reliability and validity issues of laser fluorescence measurements in occlusal caries diagnosis

OBJECTIVES Recently, a device for detecting occlusal caries lesions based on laser fluorescence measurements (DIAGNOdent) has been introduced. The reliability (reproducibility) and validity of this laser-fluorescence device were investigated. METHODS In the in vitro part of the study, 49 permanent molars were measured by two observers using two DIAGNOdent devices. In addition, visual inspection was performed. The teeth were sectioned to measure the actual depth and area of the caries lesions. In the in vivo part of the study, 45 sites at the occlusal surfaces of permanent molar teeth in 13 patients were measured by two observers using two DIAGNOdent devices, manufactured in two successive years. RESULTS The reliability of both DIAGNOdent devices expressed in the intraclass correlation coefficient (ICC=0.90 for observer 1, and 0.88 for observer 2) was high, and so was the interobserver reliability (ICC=0.85 for the 1998-device, ICC=0.90 for the 1999-device). The correlation between DIAGNOdent measurements and the actual depth of the caries lesions was lower than that of visual inspection by one observer, yet higher than that of a second observer. The specificities of visual inspection (0.94 and 0.88) were higher than those of the DIAGNOdent devices, whereas the sensitivities of the DIAGNOdent devices (0.93-1.00) exceeded those of visual inspection The validity of the DIAGNOdent, expressed as the area under the receiver operating characteristic curve, was not statistically significantly different from that of visual inspection (P>0.05). The DIAGNOdent measurements showed a higher association with the enamel part of the caries lesion than with the dentinal part. CONCLUSIONS The DIAGNOdent is suitable for monitoring small caries lesions. Because of the high reproducibility of DIAGNOdent devices produced in successive years, a DIAGNOdent device may be replaced by a new one. Due to the higher specificity, visual inspection should be preferred to diagnose occlusal caries lesions in populations with a low caries prevalence.

Propagation of light through human dental enamel and dentine

Techniques based on transillumination of teeth with visible light will be a valuable aid in caries diagnosis, if a higher sensitivity than that of the present Foti method is achieved. Therefore, a better understanding of light propagation through teeth is required, and hence it is useful to investigate the propagation of light through sound dental material. In this study the intensities emanating from the surfaces of enamel and dentine bars were measured when these bars were illuminated using a fibre rod transporting the light from a HeNe laser (lambda = 633 nm) as a light source. From the measured intensities, the radiant fluxes emanating from the surfaces were calculated. To account for a directional dependence of these fluxes, optical anisotropy in dental material was investigated by comparing the transmitted light intensity in a direction perpendicular and parallel to the approximal surface of the tooth from which the sample was cut. The mean ratio of the transmitted intensities in perpendicular and parallel direction was 0.86 +/- 0.06 for enamel and 2.88 +/- 0.43 for dentine. In addition, for enamel the asymmetry parameter, g, was estimated. The averaged value was g = 0.68 +/- 0.09. It was concluded that for dentine the optical anisotropy as measured supports the idea that tubules are the predominant cause of scattering in dentine. For enamel the results indicate that the hydroxyapatite crystals contribute significantly to scattering and that the influence of the prism structure on the light propagation is small.

Effect of 6-monthly applications of chlorhexidine varnish on incidence of occlusal caries in permanent molars : a 3-year study

OBJECTIVES The aim of this study was to assess the effect of a chlorhexidine varnish on occlusal caries incidence when applied 6-monthly into the fissures of erupting and freshly erupted permanent molars. METHODS In a double-blind clinical trial, 332 children aged 5/6 and 11/12 years attending a Child Dental Health Centre were randomly assigned to a control and an experimental group. Criteria for inclusion in the study were that all first permanent molars in 5-6-year-olds and all second permanent molars in 11-12-year-olds either had recently erupted, or were in a stage of eruption, or would erupt within half a year. At baseline, counts of dmfs/DMFS and mutans streptococci in saliva were recorded. During a maximum of 3 years, every 6 months the occlusal surfaces of molars in the experimental group received a 40% chlorhexidine varnish application, whereas those in the control group received a placebo varnish application. RESULTS Data of 316 children were analysed and ANOVA showed no significant occlusal caries reduction in this sample of Dutch 5/6- and 11/12-year-old children. After stratification into low and high caries risk groups, a statistically significant caries-reducing effect on occlusal caries in permanent molars was found in the group of children with > or = 10(6) mutans streptococci per ml saliva (P < 0.05). CONCLUSION Six-monthly application of chlorhexidine varnish has no caries-reducing effect on occlusal caries in recently erupted permanent molars in a population with low caries prevalence.

Performance of electrical resistance measurements adjunct to visual inspection in the early diagnosis of occlusal caries

The detection of small carious lesions at occlusal surfaces is a difficult task, particularly in low caries prevalence populations and individuals. The aim of this study was to evaluate the performance of electrical resistance measurements (ERM) in diagnosing small dentinal lesions at one site per occlusal surface in low caries prevalence populations when used adjunct to visual inspection, and to compare the performance of ERM to that of radiographic examination. The occlusal surfaces of 81 third permanent molar teeth extracted from young adolescents were diagnosed by four examiners, who measured the electrical resistance of enamel on a one measurement per surface basis, and furthermore assessed the occlusal surfaces visually and radiographically. The teeth were sectioned for validation by histological examination. The ERM had the highest sensitivity (0.67), and visual inspection had the highest specificity (0.89). ROC analysis showed no statistically significant differences between the performance of the observers when using visual inspection and ERM (z-score test; P > 0.05). One examiner performed statistically significantly better by measuring the electrical resistance of enamel than by radiographic examination (P < 0.05). The average sensitivity and specificity of the three diagnostic systems were used to express the positive and negative predictive values as a function of caries prevalence. At a caries prevalence of 0.2 the negative predictive values for visual inspection, ERM and radiographic examination were 0.88, 0.91 and 0.89, and the positive predictive values were 0.53, 0.48 and 0.42 respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

The real performance of bitewing radiography and fiber-optic transillumination in approximal caries diagnosis

For both general practitioners and researchers in caries diagnostics, the true validity of available diagnostic techniques is of considerable interest. Yet, for both bitewing radiography and fiber-optic transillumination, this is still not accurately known, nor is it clear which of the two techniques performs best clinically. This studys purpose was to estimate the clinical performance of the two techniques in diagnosing approximal caries lesions in low-caries-prevalence populations. Clinical studies that compare the two techniques were selected from literature. We determined 2 x 2 contingency tables from these studies and calculated one overall contingency table. The cut-off for decay was at dentinal caries. Assuming that erroneous outcomes from both techniques are mutually independent, we expressed diagnostic sensitivity and specificity of the two techniques as functions of the contingency table cell contents, with caries prevalence as the parameter. Because the caries prevalence was unknown, every sensitivity and specificity value was possible. From the conditions that sensitivity, specificity, and caries prevalence are always between one and zero, a limited range of sensitivity and specificity values was obtained. Three situations were examined: Bitewing radiography specificity is 1, fiber-optic transillumination specificity is 1, and both specificities are equal. Under these conditions, the bitewing radiography sensitivity was between 1.00 and 0.71 ± 0.01, and the fiber-optic transillumination sensitivity was between 0.70 ± 0.01 and 0.50± 0.02. Both specificities were between 1.00 and 0.99. We concluded that the two techniques have comparable specificities, but that the fiber-optic transillumination sensitivity is significantly lower than that for bitewing radiography.

Electrical conductance of fissure enamel in recently erupted molar teeth as related to caries status

Pit-and-fissure caries lesions contribute greatly to the caries incidence in permanent molar teeth in children. To date, the diagnosis of occlusal caries is still performed mainly by visual inspection, periodically aided by bite-wing radiography. However, in detecting small occlusal carious lesions, these methods perform inadequately, especially in low caries prevalence populations or individuals. The use of electrical conductance measurements (ECMs) has been evaluated to improve the diagnosis of small occlusal carious lesions. The aim of this study was to monitor the electrical conductance of fissure enamel in recently erupted molar teeth and to relate these measurements to the caries status. 50 children aged 5-15 years, having first or second permanent molars that were not exposed to the oral environment for more than 6 months, participated in the study. The diagnostic systems evaluated were visual inspection and ECMs. Following baseline data recording, diagnostic measurements were repeated three times within 18 months. Data were collected at predefined sites in the fissures. 18 months after baseline recording, 179 sites at 60 molar teeth in 27 children were judged to require a sealant based on visual inspection. After removal of carious tissue, two examiners jointly decided on the status of decay as per the criteria: 0 = no caries or caries limited to enamel, and 1 = caries involving dentine. The sensitivity of ECM continued to increase with time after a slight initial dip, whereas the specificity continuously increased after baseline measurements as a result of the decreasing amount of false-positive diagnoses.(ABSTRACT TRUNCATED AT 250 WORDS)

Electrical Conductance and Electrode Area on Sound Smooth Enamel in Extracted Teeth

Electrical conductance measurements are being used experimentally to diagnose caries. Current equipment, e.g. the electronic caries monitor (ECM), uses a probe to scan occlusal fissures. For full-mouth examination this method is rather time-consuming. A method with which only one measurement is needed for an entire (occlusal) surface would be preferable. However, the enlargement of the area being measured will influence the conductance. It was the purpose of this study to investigate the relationship between the electrical conductance of human teeth and the enamel electrode area, and to compare the range of results of surface measurements with those of the scanning method. Twenty-five sound extracted teeth were selected for the study. The reference electrode of the ECM was connected to the roots. The buccal surface was blotted dry, and a coloured dentifrice was syringed in increments onto the surface. After each increment the surface was photographed together with a metric reference, a conductance measurement was performed by holding the ECM probe tip in the dentifrice, and the ECM reading was recorded. For each tooth between 5 and 10 increments were applied and measured. The photographs were digitised and the electrode areas were calculated. A least squares curve fitting procedure yielded a linear relationship between conductance and electrode area (0.88 < or = R2 < or = 1.0, mean R2 = 0.97). For most teeth the threshold for dentinal caries as used for scanning ECM measurements (ECM reading = 6.00) was reached only when the electrode area exceeded 12 mm2. For 6 teeth this conductance was already reached between 5 and 12 mm2.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation and radiographic evaluation of four adhesive systems

OBJECTIVES The purpose of this study was to compare microleakage, gap formation, thickness of the adhesive layer and its radiographic appearance associated with four adhesive restorative procedures for class I cavities. METHODS Adhesive systems with easy handling characteristics were selected for the restoration of class I cavities in extracted third molars. Bitewing radiographs were taken of each tooth and four observers were asked to assess the presence of the adhesive layer. Microleakage, gap width and the thickness of the adhesive layer of each restoration were measured upon sectioning of the teeth. RESULTS Microleakage in the experimental restorations was minimal. The thickness of the adhesive layers and gap formation varied among different adhesive systems. The adhesive system with self-etching primer produced the highest percentage gap-free restorations. Thick adhesive layers could be detected on the radiograph. ROC analysis of the results validates the diagnosis from the radiograph. CONCLUSIONS The four restorative systems performed well in the prevention of microleakage. The use of a resin modified glass-ionomer cement base did not prevent gap formation compared with the all-etch bonding systems used in this study. The presence of an adhesive layer contributed to the prevention of gap formation, independently of the bonding system used. Thick adhesive layers could be detected on the radiograph.