Christos Rahiotis

Diagnostic performance of the visual caries classification system ICDAS II versus radiography and micro-computed tomography for proximal caries detection: An in vitro study

OBJECTIVES The purpose of this study was: (a) to compare the visual caries classification system ICDAS II with conventional (CR) and digital radiography (DR) for diagnosis of non-cavitated caries on free proximal surfaces, (b) to examine the potential of micro-computed tomography (MCT) to substitute histological examination for the in vitro caries assessment. METHODS Both proximal surfaces of 20 teeth received classification separately by two examiners by means of the diagnostic modalities examined. The teeth were sectioned and assessed for depth of the lesion. The modalities were compared in terms of degree of inter-examiner agreement, sensitivity, specificity, accuracy, positive and negative predictive value and validity. Two diagnostic thresholds were applied: no caries versus all caries scores (D1), and no dentin caries versus dentin caries (D3). RESULTS The weighted kappa values for inter-examiner reproducibility for all diagnostic modalities were 0.51-0.81. Visual examination (ICDAS II) reached significant higher sensitivity (0.92-0.96) and negative predictive value (0.9-1) than radiography. Likewise, the radiographic modalities presented significantly higher specificity (0.93-1) and positive predictive values (0.92-1) than the ICDAS II criteria. The overall accuracy performance of radiographic modalities was related to the diagnostic threshold. MCT did not agree with histological validation at each disease severity scale. CONCLUSIONS The ICDAS II criteria are a promising tool for caries diagnosis on free proximal surfaces. DR and CR radiography present comparable performance. Furthermore, MCT is not capable of constituting a reliable alternative to histological examination for caries research.

Characterization of oral films formed in the presence of a CPP–ACP agent: An in situ study

OBJECTIVES The aim of this study was to compare the morphological appearance and the molecular composition of intraoral integuments formed in situ on germanium (Ge) crystals in the presence or absence of the commercially available casein-phosphopeptide-amorphous calcium phosphate (CPP-ACP) cream agent. METHODS Six volunteers participated in the study. Impression of maxillary arch was taken for each patient, and a removable orthodontic appliance with a custom-made retainer was fabricated. Clean Ge crystals mounted in the retainers were placed intraorally for 30 min, 8, 24 h and 1-week period. The free sampling surface of another series of Ge crystals was treated with the commercial CPP-ACP agent (Tooth Mousse), mounted in the retainers and placed intraorally for the same period as above. The free exposed surfaces in oral cavity of the specimens in all subjects were examined as follows: (a) reflected light microscopy, (b) micro-MIR-FTIR spectroscopy and (c) scanning electron microscopy (SEM) plus energy-dispersive X-ray microanalysis analysis (XEDS). RESULTS The light microscopic observations revealed that there was a delay in biofilm formation on Ge surfaces treated with agent in comparison to those ones without treatment. The micro-MIR-FTIR spectra from the surfaces with Tooth Mousse showed an increase in intensity and a left shift of PO(4)(3-) peak (1064 cm(-1)). Finally, the PO(4)(3-) peak at lower bands (564 cm(-1)) and the low-wave bands at 525-530 cm(-1) increased at 1-week interval. The SEM revealed the dendritic development of microbes. The XEDS analysis showed a significant increase in Cl/O, K/O, K/Cl and a decrease in Ca/O and P/O ratios on the crystal Ge without surface treatment. On contrary, on the crystal Ge with surface treatment an increase in Ca/O, Ca/P and a decrease in K/Cl ratios were found. CONCLUSION The results show that the presence of CPP-ACP agent delays the biofilm formation and favored the nucleation and crystallization of calcium phosphates, possibly in apatitic form, in matured biofilms.

Wear and morphology of infiltrated white spot lesions

OBJECTIVES To evaluate the toothbrush wear resistance of infiltrated artificial white spot lesions following two infiltration strategies, and to assess their ultramorphology. METHODS Flat enamel surfaces from freshly extracted bovine teeth were polished and immersed in a Buskes demineralising solution for 30 days to create incipient caries-like lesions (white spots). Two experimental regions on the surface of each tooth were infiltrated with an infiltrant and a commercial etch-and-rinse adhesive. Toothbrush abrasion was applied for 20,000 cycles. Vertical wear loss of the infiltrated areas was measured after 10,000 and 20,000 cycles against unabraded and abraded enamel using confocal laser scanning microscopy (CLSM; multiple t-tests, α=0.05). Each lesions surface and cross-section were evaluated under CLSM and scanning electron microscopy after etching and infiltration to assess ultramorphology. RESULTS After 20,000 abrasion cycles, a statistically non-significant difference in vertical wear loss was measured for the infiltrant versus the adhesive compared with the original enamel (42.6±20.7 μm vs. 40.4±18.5 μm, p>0.05). Irregular surface profiles were common for the adhesive-infiltrated group as a result of peeling and blistering of the resin-covering layer. Ultramorphology of the infiltrated lesions revealed different patterns of penetration regarding density and depth. CONCLUSIONS Although both infiltration strategies had equivalent wear resistance to toothbrush abrasion, surface and morphological aspects pointed to improved surface stability and infiltration quality for the infiltrant material.

Evaluation of a new fluorescence-based device in the detection of incipient occlusal caries lesions

The aim of this in vitro study was to evaluate the performance of various contemporary detection tools at incipient occlusal caries. Thirty eight freshly extracted posterior teeth with non-cavitated occlusal caries were subjected to clinical examination and coding according to ICDAS criteria (n = 38). Standardized fluorescence images were taken with VistaProof (Dürr Dental, Bietigheim-Bissingen, Germany). Furthermore, the teeth were calculated with a laser fluorescence pen device (DIAGNOdent pen, Kavo, Biberach, Germany). In all detection methods, assessment of caries was performed twice (with 1-week interval) by two calibrated examiners. Finally, the caries lesions were validated in tooth sections by histological examination. The intra-examiner and inter-examiner kappa coefficient, sensitivity, and specificity were determined for all detection methods at enamel lesions (D1 threshold). Degrees of agreement of each method with the histological status were calculated using receiver operating characteristic statistics and the area under curve (Az values). The kappa intra-examiner/inter-examiner coefficient values (mean ± SD) were 0.74 ± 0.04/0.73 ± 0.07, 0.87 ± 0.04/0.82 ± 0.07, and 0.91 ± 0.06/0.83 ± 0.08 for clinical examination, DIAGNOdent pen, and VistaProof, respectively. The sensitivity for ICDAS was 0.80–0.86, for DIAGNOdent pen was 0.66–0.75, and for the VistaProof device was 0.97. The specificity for all the detection methods were 0.5 (0.02–0.99). The accuracy value for ICDAS was 0.76–0.81, for DIAGNOdent pen 0.66–0.71, and for the VistaProof device 0.92–0.95. The Az values (mean ± SD) were 0.431 ± 0.187, 0.583 ± 0.215, and 0.486 ± 0.207 for ICDAS, DIAGNOdent pen, and VistaProof examination, respectively. No significant differences in Az values were noted among the methods. All detection methods were presented with high inter-examiner and intra-examiner agreement. The new VistaProof device showed the best sensitivity, while DIAGNOdent pen demonstrated the worst one. Specificities were the same for all detection methods. Moreover, they presented the same performance in detection of incipient occlusal caries.

The Impact of Magnification on Occlusal Caries Diagnosis with Implementation of the ICDAS II Criteria

Aim: This study compared the impact of low-powered magnification on the detection of occlusal caries. Methods: The occlusal surfaces of 38 extracted teeth received caries ICDAS classification with and without magnification by two examiners. Histology was used as the gold standard. Results: No significant differences existed in terms of sensitivity, specificity, LR+, LR- and Az values for the two examiners and modalities. Interexaminer agreement was almost perfect for grades 0, 2, 3 irrespective of magnification. For grade 1, magnification resulted in lower agreement than unaided vision. Conclusion: Magnification does not improve the detective performance of visual examination.

Decision-making and preventive non-surgical therapy in the context of a European Core Curriculum in Cariology.

This paper is part of a series of papers towards a European Core Curriculum in Cariology for undergraduate dental students. The European Core Curriculum in Cariology is the outcome of a joint workshop of the European Organisation for Caries Research (ORCA) together with the Association for Dental Education in Europe (ADEE), which was held in Berlin from 27 to 30 June 2010. The present paper covers decision-making and non-surgical treatment. In particular, it will provide some background information on this part of the European core curriculum. The dentist, on graduation, must be competent at applying the principles of prevention of dental hard tissue disease processes (primary prevention) and progression when it has manifested itself (secondary prevention). The competences should apply in differing ways to patients of all ages. Goals of prevention should be clearly defined in order for outcomes to be evaluated, and a dentist should be competent at determining these outcomes. Although this concept is recognised by many academics and experts, clinical teaching, practice and health insurance coverage frequently emphasise surgical treatment. There are many reasons and obstacles that might account for this, and this paper suggests some reasons why this might be and makes suggestions for how these can be addressed in the future. One factor that is essential in the provision of a preventive, non-surgical approach is that of communication with the patient. However, this unfortunately takes less space in the dental curricula compared with technical skills aimed at restorative procedures; this weighting needs to be more equally balanced.

Setting characteristics of a resin infiltration system for incipient caries treatment.

OBJECTIVES This study investigated the curing efficiency, the extent of atmospheric oxygen inhibition to the polymerization reaction and the mechanical properties of a new resin-infiltration system for caries treatment. METHODS The curing efficiency was estimated by measuring the percentage degree of cure (%DC) of thin resin films (h: 150μm, Ø: 5mm, n=3), 10min after 40s exposure to a quartz halogen bulb (750mW/cm2) light curing unit (Optilux 501, Demetron/Kerr, USA), in the absence of O2, by micro ATR-FTIR spectroscopy. The extent of O2 inhibition on resin film setting (width in μm) was assessed by transmission optical microscopy on thin films (h: 150μm, Ø: ∼7mm, n=5) placed between two transparent cover slips and exposed to air from lateral sites. For each sample the extent of inhibition was measured at 5 different locations. The mechanical properties were tested employing Instrumented Indentation Testing according to ISO 14577:2002. Resin specimens (h: 2mm, Ø: 10mm, n=5) were prepared employing cylindrical teflon moulds enclosed in transparent matrix strips and glass slides as before. The measurements were performed employing a Vickers indenter attached to a universal hardness testing machine (ZHU2.5/Z2.5 plus test Xpert software, Zwick/Roell, Ulm, Germany). The parameters tested were Martens Hardness (MH), Vickers Hardness (VHN), Indentation Elastic Modulus (EIT) and elastic to total ratio of indentation work (ηIT). For all these tests, specimens of a conventional light-curing bonding resin (HB-Heliobond, Ivoclar-Vivadent, FL) prepared as above were used as control. Student t-test was used to identify statistically significant differences between the two materials in the parameters tested (a: 0.05). RESULTS The results of the materials tested were: (a) [% DC]; IC: 57.4±1.5, HB: 59.8±2.4, (b) [Width of O2 inhibition/μm]; IC: 33.1±6.5, HB: 23.6±4.4, (c) [MH/N/mm(2)] IC; 116±16, HB: 261±35, (d) [VHN]; IC; 15.4±2.5, HB: 22.1±1.8, (e) [EIT/(GPa)]; IC; 2.3±0.4, HB: 7.5±0.5, and (g) [ηIT (%)] IC; 50.3±3.4, HB: 35.1±1.9. The IC presented no significant difference in terms of % DC, higher thickness of the inhibited layer, lower MH, VHN, EIT and greater ηIT values than HB. CONCLUSIONS AND CLINICAL SIGNIFICANT The resin-infiltrating system for incipient caries treatment demonstrated the same curing efficiency with a conventional unfilled bonding resin, but exhibited higher extent of oxygen inhibition, lower hardness, lower elastic modulus and higher plastic to elastic indentation energy.

Early responses of human pulp to direct capping with resin adhesive systems and calcium hydroxide

OBJECTIVE Early responses of human pulp to Prime&Bond/phosphoric acid, Clearfil SE Bond, Clearfil S3 Bond and Dycal were investigated ex vivo. MATERIALS AND METHODS The three adhesives, Dycal or buffer (DPBS) were applied directly onto the pulp of human teeth slices that were placed in culture for 4 days. Cell viability was monitored by the MTT assay during the culture period. After 4 days, tissue integrity was examined by hematoxylin-eosin staining. Vimentin levels were assessed by Western blotting. TUNEL assay was applied for apoptotic cell detection at specific pulp areas. RESULTS Profound reduction of cell viability and tissue integrity was observed in adhesive-treated groups, while the impact of Dycal was found to be less harmful. Extended apoptosis was caused mostly by the Clearfil SE and Prime&Bond. All adhesives reduced Vimentin levels. SIGNIFICANCE The study provides evidence that early pulp responses to direct capping with different adhesive systems or calcium hydroxide may vary significantly and underline the need for further studies in relevant ex vivo systems.

Research on Orthodontic Polymers

Research on orthodontic polymers involves the study of a wide array of materials used in a spectrum of orthodontic applications. Table 2.1 summarizes these materials and applications.