Laser fluorescence measurements compared to electrical resistance of residual dentine in excavated cavities in vivo

Comparative evaluation and patient satisfaction with an electrical impedance-based device versus digital radiography in the estimation of remaining dentin thickness in carious posterior permanent teeth: (Diagnostic accuracy study)

BACKGROUND

Accurate assessment of remaining dentin thickness (RDT) is paramount for restorative decisions and treatment planning of vital teeth to avoid any pulpal injury. This diagnostic accuracy study compared the validity and patient satisfaction of an electrical impedance based device Prepometer™ (Hager & Werken, Duisburg, Germany) versus intraoral digital radiography for the estimation of remaining dentin thickness in carious posterior permanent teeth.

METHODS

Seventy patients aged 12-25 years with carious occlusal or proximal permanent vital posterior teeth were recruited. Tooth preparation was performed to receive an adhesive restoration. Pre- and post-excavation RDT were measured radiographically by two calibrated raters using the paralleling periapical technique. Prepometer™ measurements were performed by the operator. Patients rated their satisfaction level with each tool on a 4-point Likert scale and 100 mm visual analog scale (VAS). Inter and intragroup comparisons were analyzed using signed rank test, while agreement between devices and observations was tested using weight kappa (WK) coefficient.

RESULTS

the intergroup comparisons showed that, before and after excavation, there was a significant difference between measurements made by both techniques (p < 0.001). After excavation, there was a weak agreement between measurements (WK = 0.2, p < 0.001), whereas before excavation, the agreement was not statistically significant (p = 0.407). Patients were significantly more satisfied with Prepometer™ based on scales and VAS (p < 0.001).

CONCLUSION

Prepometer™ could be a viable clinical tool for determining RDT with high patient satisfaction, while radiographs tended to overestimate RDT in relation to the Prepometer™.

Accuracy of an electrical impedance device in estimation of remaining dentin thickness vs cone beam computed tomography

The objective of this study is to compare the estimated values of remaining dentin thickness (RDT) recorded by a newly introduced electrical impedance device (Prepometer) with cone beam computed tomography (CBCT) and histological in situ measurement. A total number of thirty human molars were used in this study. A deep class I cavity was prepared. The RDT for each cavity was measured with Prepometer in three different points (mesial, middle, and distal). Same specimens were imaged with high-resolution Cone Beam Computed Tomography CBCT (0.1 mm voxel size) using I CAT next Generation Machine (Imaging Science International, Hatfield, PA, USA), to provide the highest possible accuracy of linear measurements. Finally, the specimens were vertically sectioned parallel to the long axis of the tooth in a mesiodistal direction splitting the cavity into two halves through its center. Then, the actual RDT of each half will be measured in the same three points using a digital caliper. The outcome of one-way ANOVA revealed that there was no significant difference in RDT values measured by prepometer device, CBCT, or histological sectioning methods (p > 0.05). Within the limitations of this laboratory study, prepometer seems to be a potential non-invasive accurate measuring tool for RDT. Based on the findings of this study, the Prepometer can be considered as an easily handled and less-expensive method compared to CBCT to evaluate the RDT. Also, it can be used in dental schools and with less-experienced operators to avoid traumatic exposures of the dental pulp.

Clinical Evaluation of Ozone on Dentinal Lesions in Young Permanent Molars using the Stepwise Excavation

AIM

To evaluate the clinical changes in dentin of deep carious lesions in young permanent molars, following ozone application with and without the use of a remineralizing solution, using the stepwise excavation.

STUDY DESIGN

The sample included 162 first permanent immature molars, showing deep occlusal carious cavities that were indicated for indirect pulp capping. Teeth were divided into 2 main groups according to the method of ozone treatment. Each group was further subdivided equally into test and control subgroups. Following caries excavation, color, consistency and DIAGNOdent assessments of dentin were evaluated after 6 and 12 months.

RESULTS

Regarding dentin color and consistency, no significant differences were observed following ozone application, with and without a remineralizing solution. There were no significant differences between ozone treatment, and calcium hydroxide during the different evaluation periods, except in group I cases after 6 months, concerning the dentin color. The DIAGNOdent values were significantly reduced following ozone application, with or without a remineralizing solution, as well as between test and control cases in group I after 6 months.

CONCLUSIONS

Ozone application through the stepwise excavation had no significant effect on dentin color and consistency in young permanent molars. DIAGNOdent was unreliable in monitoring caries activity.

Evaluation of dental explorer and visual inspection for the detection of residual caries among Greek dentists

Objectives

The objective of this study was to assess the effect of the operator's degree of clinical experience on the residual caries diagnosis through visual inspection and tactile sensation.

Materials and Methods

The participants were asked about the years of their clinical practice, any further training concerning cariology, their familiarity with the minimal invasive philosophy, and the techniques that they use to remove dental caries and detect when to stop the removal of carious tissues. In addition, an in vitro diagnostic test was conducted. Carious teeth were excavated to a level selected in random. Teeth were examined by each participant individually. Initial examination was performed by visual inspection. Subsequently, a dental explorer was used concerning the potential need for further removal of dental tissues. A sample of 380 dentists and dental school students were selected for the purposes of this study.

Results

Dental students presented statistically significant better sensitivity, than dentists from both age groups, during both visual inspection and tactile sensation of residual caries. Participants' ability to diagnose residual caries during cavity preparation was independent of their years of experience.

Conclusions

During the removal of carious lesions, with the goal of limiting the sacrifice of healthy structures and the leftover of residual caries, clinicians should combine a selective removal technique and the attentive visual inspection, with at least one further diagnostic method, aside from the dental explorer. Tactile examination of residual caries solely with the dental explorer must be used with attention.

In Vitro Comparison of Diagnostic Accuracy of DIAGNOdent and Digital Radiography for Detection of Secondary Proximal Caries Adjacent to Composite Restorations

Introduction: Early detection of secondary proximal caries is critical for the preservation of tooth vitality. This study sought to assess and compare the diagnostic accuracy of DIAGNOdent and digital radiography for detection of secondary proximal caries adjacent to composite restorations. Methods: Sixty extracted molars including 30 teeth with carious lesions and 30 sound teeth were randomly selected. Class II cavities were prepared in all teeth and carious dentin was intentionally left in the gingival floor of cavities in 30 carious teeth. All cavities were restored with composite resin. The teeth were mounted in wax blocks (three teeth per block) and examined for caries using (DIAGNOdent kaVo Dental, Biberach, Germany). Digital radiographs using DIGORA photostimulable phosphor (PSP) plates (Soredex Corporation, Helsinki, Finland) were obtained from all teeth using the parallel technique and were evaluated by 4 observers. Repeated measure analysis of variance (ANOVA) was applied to calculate sensitivity and specificity values of the two diagnostic techniques. Receiver operating characteristic (ROC) curve was plotted for DIAGNOdent results and based on that, the cutoff points were determined. Results: The sensitivity and specificity values at the cut-off point of 10.5 were 0.622±0.038 and 0.822±0.077 for DIAGNOdent and 0.591±0.093 and 0.891±0.083 for digital radiography, respectively. The area under the ROC curve was 0.7 for DIAGNOdent. Weighted kappa revealed moderate to almost perfect intra-observer agreement (0.46-0.99). Intraclass correlation coefficient (ICC) for DIAGNOdent was calculated to be 0.88. Conclusion: No statistically significant difference was noted in diagnostic accuracy of DIAGNOdent and digital radiography for detection of secondary proximal caries adjacent to composite restorations. Thus, DIAGNOdent may be used as an adjunct diagnostic tool for detection of secondary proximal caries beneath composite restorations.

Comparison of two different methods of detecting residual caries

Objectives

The aim of this study was to investigate the ability of the fluorescence-aided caries excavation (FACE) device to detect residual caries by comparing conventional methods in vivo.

Materials and Methods

A total of 301 females and 202 males with carious teeth participated in this study. The cavity preparations were done by grade 4 (Group 1, 154 teeth), grade 5 (Group 2, 176 teeth), and postgraduate (Group 3, 173 teeth) students. After caries excavation using a handpiece and hand instruments, the presence of residual caries was evaluated by 2 investigators who were previously calibrated for visual-tactile assessment with and without magnifying glasses and trained in the use of a FACE device. The tooth number, cavity type, and presence or absence of residual caries were recorded. The data were analyzed using the Chi-square test, the Fisher's Exact test, or the McNemar test as appropriate. Kappa statistics was used for calibration. In all tests, the level of significance was set at p = 0.05.

Results

Almost half of the cavities prepared were Class II (Class I, 20.9%; Class II, 48.9%; Class III, 20.1%; Class IV, 3.4%; Class V, 6.8%). Higher numbers of cavities left with caries were observed in Groups 1 and 2 than in Group 3 for all examination methods. Significant differences were found between visual inspection with or without magnifying glasses and inspection with a FACE device for all groups (p < 0.001). More residual caries were detected through inspection with a FACE device (46.5%) than through either visual inspection (31.8%) or inspection with a magnifying glass (37.6%).

Conclusions

Within the limitations of this study, the FACE device may be an effective method for the detection of residual caries.

Desempenho de métodos baseados em indução de fluorescência na avaliação da remoção de dentina cariada

Resumo Introdução Critérios clínicos vêm sendo utilizados para determinação da presença de tecido cariado remanescente, mas geram dúvidas, tornando-se relevante a utilização de métodos que auxiliem na determinação da presença de cárie dentária remanescente. Objetivo Avaliar in vitro a eficácia de métodos de indução de fluorescência no diagnóstico da remoção de tecido cariado artificial dentinário. Material e método O esmalte oclusal de 94 terceiros molares humanos hígidos foi removido, expondo a dentina subjacente, para indução microbiológica de lesão de cárie artificial. Após a remoção do tecido cariado induzido, o remanescente dentinário foi avaliado por dois examinadores com DIAGNOdent, DIAGNOdent pen e Quantitative Light-Induced Fluorescence (QLF). Após todas as avaliações, secções dos dentes foram observadas e fotografadas em lupa estereoscópica com 30× de aumento por um examinador independente. As imagens foram analisadas no software Image J, permitindo a quantificação de tecido remanescente em milímetros quadrados. Foi calculada a reprodutibilidade interexaminador através de coeficiente intraclasse, sensibilidade, especificidade e área sob a curva ROC, e o teste de McNemar (p<0,05) foi aplicado para comparação dos diferentes métodos. Resultado Dos 94 dentes, 51 (54,2%) apresentaram remanescente de tecido cariado. Os valores de sensibilidade, especificidade e área sobre a curva ROC foram semelhantes para os três grupos (p>0,05). Os valores de reprodutibilidade variaram entre 0,952 e 0,978. Conclusão Dentre os métodos utilizados, o DIAGNOdent e o DIAGNOdent pen apresentaram melhor desempenho na avaliação da presença de cárie artificial remanescente quando comparados ao QLF.

Construction and in vitro test of a new electrode for dentin resistance measurement

It is necessary to reduce the tooth substance before treating a tooth with a dental crown. The preparation often requires reduction of the dentin. This results in a dentin wound and a thinner substance over the pulp, increases the risk of inflammation, and could result in necrosis of the pulp. To give the dentist information about the amount of dentin over the pulp during preparation, the Prepometer was developed. The function of this device is based on the measurement of the electric resistance of the tooth substance. The measuring behavior of the first-generation Prepometer is characterized by smaller values of electric resistance before reaching full contact of the measuring head to the dentin surface and the actual value RT. This measuring behavior can mislead inexperienced therapists with inaccurate values that suggest thinner dentin than the reality. In this study, a new electrode based on the technology of active guard drive was constructed to overcome this issue. The results show that improvement in the measuring behavior of the new electrode could be achieved, eliminating the earlier disadvantage of the Prepometer.

In vivo assessment of caries excavation with a fluorescence camera compared to direct bacteriological sampling and quantitative analysis using flow cytometry

The aim of this study was to assess the performance of the fluorescence camera device VistaCam iX (VC) for the control of caries excavation compared to visual assessment and bacteriological evaluation. Twenty-three patients with 32 dentinal carious lesions were included in the study. The lesions were classified using the International Caries Detection and Assessment System. Fluorescence images were taken at the surface of each lesion using the VC before excavation (stage 1), during (stage 2) and after excavation (stage 3). At each stage, dentine samples were collected. All cavities were closed after excavation using permanent fillings. Bacteria were counted within each dentine sample using flow cytometry. Significant moderate correlation between the fluorescence readings and the bacteria count was found at stage 3 (Spearman correlation coefficient rs = 0.40, p = 0.027). Area under the ROC curve (AUC) was calculated for fluorescence readings and bacteria count using the clinical status at stage 3 as a reference. AUC was 0.954 for the VC readings and 0.797 for bacteria count. Using the median bacteria count at stage 3 as a reference, the AUC for the fluorescence readings was 0.753. The results indicate that the fluorescence camera appears to be a useful supplementary tool in assessing the endpoint of caries excavation with the advantage of enabling data to be digitally visualized and stored. When an experienced dental clinician determined the excavation endpoint, the performance with respect to remaining bacteria count was good.

Caries diagnosis using light fluorescence devices: VistaProof and DIAGNOdent

The modern concept of minimally invasive dentistry encompasses early detection of incipient carious lesions and their treatment. Due to the low sensitivity of visual inspection and radiography in the detection of occlusal hidden carious lesions under a macroscopically sound surface, several devices have been developed to increase detection accuracy. DIAGNOdent is one of the tools used for that purpose and VistaProof is a new device recently introduced into the market. They both use light fluorescence to detect incipient carious lesions. DIAGNOdent is based on the fact that carious lesions show higher level of fluorescence than sound tissues when excited by light at specific wavelength. Vistaproof is based on the same principle, but it uses a different wavelength of excitation than DIAGNOdent and a video camera for the detection of fluorescence. The aim of this article was to compare these two devices and present their clinical use.

Evaluating the efficiency of caries removal using an Er:YAG laser driven by fluorescence feedback control

INTRODUCTION

Caries lesions in dental hard tissues autofluoresce when exposed to light of certain wavelengths, whereas sound tissues do not, and this can be used as an in vitro histological marker for dental caries. Detection of autofluorescence is the basis of KaVo DIAGNOdent™ technology, and provides objective feedback control of laser-stimulated ablation of dental caries for the KaVo Key Laser 3™. This Er:YAG laser operates at 2940nm wavelength, and is effective at removal of infected dental hard tissues. Micro-computed tomography (micro-CT) allows the non-invasive investigation of three-dimensional structures and analysis of mineral density profiles of dentine following laser ablation.

OBJECTIVE

To evaluate removal of infected, demineralised dentine by Er:YAG irradiation with a laser feedback mechanism, using micro-CT.

DESIGN

27 carious teeth (1 control) and 1 sound tooth, treated with the KaVo Key Laser 3™ using a KaVo™ non-contact 2060 handpiece at specific feedback settings, were examined using a Skyscan 1172 Micro-CT, to observe the efficiency of demineralised dentine removal. Grey scale images obtained were colour rendered to assist detection of demineralised tissue if present.

RESULTS

Complete removal of demineralised tissue occurred with laser-stimulated ablation under feedback control at values of 7 and 8 when measured by micro-CT. At greater values, removal of demineralised dentine was incomplete.

CONCLUSION

Examination of dental tissues by micro-CT allowed determination of the efficiency of Er:YAG laser-stimulated ablation. Feedback control of the KaVo Key Laser 3™ appeared to operate like a cut-off switch when infected dentine was eliminated, at a threshold of between 6 and 7.

Does DIAGNOdent provide a reliable caries-removal endpoint?

OBJECTIVES

To compare mineral density of residual dentine after excavation with different caries-removal techniques and to evaluate the diagnostic potential of laser-induced fluorescence (LIF), measured by DIAGNOdent, as a tool to determine the caries-removal endpoint.

METHODS

Carious teeth were excavated by tungsten-carbide round burs (Komet), ceramic burs (CeraBurs, Komet), sono-abrasion (Cariex TC tips, Kavo), and by chemo-mechanical excavation using two enzyme-based solutions (exp. SFC-V and SFC-VIII, 3M-ESPE) or a sodium hypochlorite-based solution (Carisolv, MediTeam). The caries-excavated teeth were scanned by micro-CT (1172, Skyscan), after which the mineral density at the bottom dentine was correlated to LIF measurements at the same region. A micro-CT threshold for dentine caries was defined by comparison with surface-hardness measurements. The intensity of dentine staining was evaluated by analysing the component 'L*' in CIE-L*a*b-converted images from the excavated teeth.

RESULTS

No statistically significant difference in mineral density was found at the bottom of the cavities prepared with the different caries-excavation techniques, except for exp. SFC-V that left residual dentine with a significantly higher mineral density than when CeraBurs were used (Tukey-Kramer, p<0.05). Absence of residual caries was associated with darker staining of dentine. No significant correlation was found between the distance from the deepest cavity point to the pulp-chamber roof and LIF measurements. A strong negative correlation (R=-0.86, p<0.01) was however found between L* values and LIF measurements, indicating that staining in residual dentine leads to higher LIF measurements.

CONCLUSIONS

LIF measured by DIAGNOdent is influenced by staining in residual dentine. Therefore, its use to determine the caries-removal endpoint is doubtful.

Dental caries: A complete changeover, PART III: Changeover in the treatment decisions and treatments

Comprehensive management of dental caries should involve the management of disease as well as the lesion. Current decision making process in cariology is influenced by numerous factors such as the size/ depth/ activity of the carious lesion and age/ the caries risk status of the patient. Treatment decisions should involve planning the non-operative/ preventive treatment for non-cavitated or early cavitated lesions and also formulating operative treatment for cavitated lesions. Apart from these two responsibilities, a clinician should also be knowledgeable enough to decide when not to interfere in the caries dynamics and how frequently to recall the patient for follow-ups. The non-operative treatment prescriptions vary in dose, intensity and mode of delivery according to the caries risk status. Minimal invasion and maximal conservation of tooth structure has become the essence of current operative treatments. This part of the series elaborates on the paradigm shift in the management of dental caries.

A rapid nondestructive method for root dentin moisture measurements: in vitro pilot study

Dentin moisture content is important in adhesive bonding and structural strength research; however, there is no rapid method available to assess dentin moisture without sample destruction. This study examined the use of a digital grain moisture meter to measure root dentin moisture in vitro. Extracted mandibular single-rooted teeth were sectioned at the CEJ. The moisture of the root dentin was measured at 6 measuring modes for different grains and repeated 5 times. Dentin weight changes before and after drying were measured to obtain control values. The control values were compared with machine readings. In conclusion, (1) each nondestructive measurement took less than 30 seconds, (2) 24 hours of storage at 37 degrees C and 100% humidity did not restore dentin moisture, and (3) 5 grain modes had a high validity and could be used for dentin moisture measurements.

Fluorescence of primary dentine after chemomechanical and conventional rotary excavation

AIM

This was to compare fluorescence values of dentine remaining after caries removal using chemomechanical systems and conventional rotary methods.

STUDY DESIGN

In vitro study.

METHODS

30 extracted primary teeth with proximal carious cavities were divided into three groups according to caries removal method: Carisolv, Papacarie and conventional low speed rotary burs. Carious (initial) and remaining (final) dentine evaluations were assessed by visual-tactile examination and DIAGNOdent. Transversal microhardness (TMH) of remaining dentine was evaluated. Fluorescence and TMH values were submitted to two-way ANOVA and the post hoc Tukey test (alpha = 0.05) and Pearson's linear correlation.

RESULTS

Two-way ANOVA revealed that fluorescence values were similar between conventional rotary excavation, Carisolv and Papacarie groups (p = 0.0542). No statistically significant differences (p = 0.1147) were found to TMH values. No correlation was found between fluorescence and TMH values (r = -0.0273).

CONCLUSION

All caries excavation methods resulted in similar remaining dentine fluorescence values. No correlation was found between fluorescence values and TMH of remaining dentine.

The influence of zero value subtraction on the performance of a new laser fluorescence device for approximal caries detection

The aim of this study was to assess the influence of the zero value subtraction on the performance of laser fluorescence (LFpen) for approximal caries detection. Three areas (cuspal, middle and cervical) of both mesial and distal buccal surfaces of 78 permanent molars were assessed using both wedge-shaped (WDG) and tapered wedge-shaped (TWDG) tips. With the addition of the average, one cut-off value for each area was obtained and the performance was assessed. The areas under the receiver operating characteristics (ROC) curve, specificity, sensitivity and accuracy with and without the zero value subtraction were calculated. The McNemar test revealed a statistically significant difference for specificity at thresholds D(1), D(2) and D(3) (WDG) and D(1) and D(2) (TWDG) when the zero value subtraction was not performed. Influence of the zero value subtraction on the LFpen performance was observed for approximal caries detection. However, when modified cut-off values were used, the zero value subtraction could be eliminated.

Evaluation of selective caries removal in deciduous teeth by a fluorescence feedback-controlled Er:YAG laser in vivo

This study investigated the ability and efficacy of an Er:YAG laser with a fluorescence feedback system for caries removal in deciduous teeth. Seventy-nine carious lesions were excavated using a fluorescence-controlled Er:YAG laser. Endpoint of treatment was defined by emission of fluorescence from the dentine surface below the pre-selected threshold level of 7 units and the subsequent termination of Er:YAG laser radiation. Dentine samples were obtained from the cavity floor, and viable counts of both Streptococcus mutans and Lactobacilli, expressed as colony forming units (log CFU), were evaluated. Preparation time was recorded to assess efficacy of the treatment procedure. S. mutans and/or Lactobacilli were found in 25 out of 79 lesions. Regarding the counts for S. mutans and Lactobacilli, the median log CFU was 0 (min, 0; max, 5.5) and 0 (min, 0; max, 6), respectively, with 2.4% of all samples yielding more than 100 CFU S. mutans and 4.8% yielding more than 100 CFU Lactobacilli. In 8 out of 79 cases, laser excavated cavities were not judged being caries-free using the conventional tactile criterion for assessing caries tissue. Focussing on these teeth, the median log CFU was 0 (min, 0; max, 0.5) for S. mutans and 0 (min, 0; max, 1.6) for Lactobacilli. The mean time for treatment was 2.3+/-1.2 min. Of the children, 93.8% rated the laser treatment to be comfortable. The study indicates that the fluorescence feedback-controlled Er:YAG laser might be an appropriate device for caries removal in children using the suggested threshold level of 7 units.

Comparison of two laser fluorescence devices for the detection of occlusal caries in vivo

Laser fluorescence measurements have been shown to be well suited for caries diagnosis. The aim of this study was to compare two laser fluorescence devices and to correlate the respective values with the visual and radiographic assessment and with the extent of the carious lesion. Ninety-four clinically non-cavitated occlusal carious lesions in the premolars and molars of 82 patients were examined. Laser fluorescence values on the surface were measured with a conventional laser fluorescence system and a novel laser fluorescence pen device. When operative intervention at a site was indicated, the extent of caries was determined after its removal. Readings obtained with both systems were significantly different with an interdevice factor of 0.64. Sensitivity and specificity for operative care were 92.6% and 53.7%, respectively, for the conventional, and 88.9% and 53.7%, respectively, for the pen device. For both devices, a correlation between laser fluorescence values and the visual and radiographic assessment and with the extent of the lesion was shown. The study indicates that the novel laser fluorescence device seems to be suitable for occlusal caries diagnosis. However, proposed guidelines for the clinical use of laser fluorescence readings of the conventional device cannot be transferred to the novel pen system.