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Objectives The aim of this in vivo prospective clinical study was to validate a near-infrared light transillumination (NILT) device for the detection of proximal caries lesions and compare it to the established diagnostic method of bitewing radiography (BWR). Materials and methods A total of 116 interproximal posterior teeth/surfaces without gross cavitation were included and assessed with BWR and NILT. After clinical examination, the teeth with sound surfaces or non-cavitated caries lesions were separated with the use of an orthodontic separation rubber for 24 h. Upon removal of the separator a silicon impression was obtained and the teeth surfaces were directly investigated. Intra- and inter-examiner reproducibility, sensitivities (SE) and specificities (SP) as well as the area under ROC curves (AUC) were calculated. Results The SE of NILT was 0.92 in D1 lesions and 1.00 in D2 and D3 lesions, respectively. BWR showed SE values of 0.81 in D1 lesions, 0.74 in D2 and 1.00 in D3 lesions, respectively. However, NILT showed lower values of SP (D1 0.38, D2 0.42 and D3 0.99) compared to BWR (D1 0.65, D2 0.88, D3 1.00). Intra-examiner reproducibility increased for both examiners from the initial examination (0.68 and 0.62) to the recall appointment (0.89 and 0.76) respectively. Conclusion The performance of NILT in detection of enamel caries was comparable to BWR. NILT could be considered as a useful and reliable tool in clinical practice. However, monitoring of enamel lesions might not be accurate, since a low specificity of NILT at D1,2 level and a tendency to false positive ratings have been shown. Therefore, it is recommended that treatment decisions should not be based on NILT alone. Clinical relevance This study might indicate that NILT can be used for routine patient screening but the use of BWR is still important for treatment decisions.

Objectives Matrix metalloproteinases (MMPs) in dentin and saliva can degrade collagen. Divalent metals are known inhibitors of MMPs, but stannous – such as in the form of stannous chloride (SnCl2) or stannous fluoride (SnF2) – is yet to be tested for a possible inhibitory effect. In this study, we tested the inhibitory effect on the proteolytic activity of MMP-2 and MMP-9. Methods Sodium chloride (NaCl), sodium fluoride (NaF), and chlorhexidine (CHX) were used as controls. Gelatin zymography was performed with recombinant human MMP-2 and MMP-9. SnCl2, SnF2, NaF, NaCl, and CHX were included either in the incubation buffer (M1) or added to the recombinant MMPs (M2) before the MMPs were analyzed using zymography. Furthermore, the effect of SnCl2, SnF2, and NaF on the enzymatic activity of MMP-2 and MMP-9 was measured in human dentin either before or after acid etching using 37%phosphoric acid. The effect of SnCl2, NaF, and CHX on the viability and of SnCl2 and NaF on the proliferation of human gingival fibroblasts and L929 mouse fibroblasts was also determined. Results For M1, inhibitory concentrations (w/v%) of SnCl2 0.5% and 0.5%, SnF2 0.25% and 0.12%, NaF 0.12% and 0.5%, CHX 0.012% and 0.05%, were observed for MMP-2 and MMP-9, respectively. NaCl had no inhibitory effect. For M2, SnCl2 0.007% and 0.12%, and SnF2 0.03% and 0.5%, inhibited MMP-2 and MMP-9, respectively. NaF, NaCl and CHX had no effect. The enzymatic activity was slightly reduced when SnCl2 and NaF were applied on dentin before the acid attack. Regarding cell viability and proliferation of the cells after stimulation with the respective substances, NaF showed almost no effect, SnCl2 appeared to increase viability and proliferation of the cells, and CHX decreased the viability of cells. Conclusions Stannous ions caused a direct inhibition of the matrix metalloproteinases, whereas F− only had an inhibitory effect when added to the zymography buffer. Clinical significance Inhibition of MMPs using SnCl2 and SnF2 could play an important role in the prevention of dental erosion and caries. However, the clinical relevance of these findings needs to be proven.

Made available in DSpace on 2019-10-06T16:41:49Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-01-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Objective: This study analyzed the effect of desensitizing and/or anti-erosive toothpastes on dentine permeability. Methods: One-mm dentin discs were prepared from human molars and exposed to EDTA solution (5 min, 17%). Initial dentine permeability was measured, under constant pressure. Specimens were randomly allocated into 10 groups: four anti-erosive toothpastes (calcium silicate + sodium phosphate, potassium nitrate, stannous chloride + chitosan, oligopeptide-104); four desensitizing toothpastes (arginine + calcium carbonate, calcium sodium phosphosilicate, strontium acetate, stannous fluoride); and two controls (regular fluoridated toothpaste, and human saliva). They were submitted to a 5-day erosion-abrasion cycling model. Erosion consisted of immersion in citric acid (2 min, 0.3%, natural pH ˜ 2.6, 4x/day), followed by 1 h exposure to human saliva. Specimens were brushed for 15 s (2 N, 45 strokes) with the toothpaste slurries (total exposure time of 2 min). After 5 cycles, the final dentine permeability was determined. Dentine permeability change was calculated as a percentage of the initial hydraulic conductance (%Lp). Data were analyzed with one-way ANOVA and Tukey tests (α=0.05). Results: The toothpastes calcium silicate + sodium phosphate and potassium nitrate, showed significant decrease in %Lp, with no difference between them. The regular fluoridated toothpaste also decreased the %Lp, not differing from potassium nitrate. No desensitizing toothpaste showed change in %Lp. Human saliva, oligopeptide-104 and stannous chloride + chitosan presented significant increase in %Lp, without difference between them. Conclusion: Calcium silicate + sodium phosphate, potassium nitrate, and the regular fluoridated toothpaste decreased dentine permeability, whereas the desensitizing toothpastes tested did not. Clinical relevance: Toothpastes had distinct impacts on dentine permeability, which may reflect a variable effect on the treatment of dentine hypersensitivity. Within the limitations of a laboratory-based study, toothpastes with an anti-erosive claim could also be effective in reducing the pain in dentine hypersensitivity. Department of Restorative Dentistry School of Dentistry University of São Paulo Cidade Universitária, Av. Prof. Lineu Prestes 2227 Department of Restorative Dentistry Institute of Science and Technology São Paulo State University - UNESP, Av. Eng. Francisco José Longo 777, São José dos Campos Department of Restorative Preventive and Pediatric Dentistry University of Bern, Freiburgstrasse 7 Department of Restorative Dentistry Institute of Science and Technology São Paulo State University - UNESP, Av. Eng. Francisco José Longo 777, São José dos Campos FAPESP: #2015/14117-2

Objectives The study evaluated the suitability of pure crystalline hydroxyapatite (HA) as a substitute for human (H) and bovine (B) enamel in erosion experiments. Methods Human and bovine enamel and hydroxyapatite specimens (n = 18 each) were submitted to demineralisation by HCl at pH values of 3.0, 2.6 and 2.0 (1.0, 2.5, and 10 mmol/l concentration). Specimens were eroded in a superfusion chamber for 7 min (flow rate: 1 μl/s). Multiple fluid samples were taken per specimen throughout the exposure period. The dissolved calcium content was measured using a colorimetric assay with Arsenazo III reagent, to serve as surrogate for erosive substance loss. Additionally, erosive tissue loss was quantified by profilometry. Differences in erosive substance loss were assessed by the Kruskal-Wallis and Conover’s posthoc test. Results Good agreement in erosive substance loss between HA and human specimens was found at pH 2.6, as no statistically significant difference and considerable overlap of their respective interquartile ranges was observed. At pH 2.0 and 3.0, a statistically significant difference between HA and human and bovine enamel was determined. HA consistently tended to have lower mean dissolution rates, with a maximum deviation from human enamel of -16% at pH 3. It displayed lower specimen variability with an average coefficient of variation of 17%, compared to 25% (H) and 25% (B), respectively. Conclusions Crystalline hydroxyapatite may not be suitable for full substitution of biologic enamel in erosion experiments focusing on absolute measurement values, but is useful for establishing consistent relative trends between erosive agents due to biosimilar erosion behavior and lower experimental variability. This is especially true for preliminary studies where approval for use of biological samples is restricted. Clinical significance Crystalline hydroxyapatite is a useful substitute of human or bovine enamel in experiments studying chemical aspects of dental erosion.

Made available in DSpace on 2021-06-25T15:20:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-04-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Objective: This study investigated the mechanism of action of different proteins/peptides (separately or in combination), focusing on how they act directly on the native enamel surface and on modifying the salivary pellicle. Methods: A total of 170 native human enamel specimens were prepared and submitted to different treatments (2 h; 37 degrees C): with deionized water, CaneCPI-5, Hemoglobin, Statherin, or a combination of all three proteins/peptides. The groups were subdivided into treatment acting on the enamel surface (NoP - absence of salivary pellicle), and treatment modifying the salivary pellicle (P). Treatment was made (2 h; 37 degrees C) in all specimens, and later, for P, the specimens were incubated in human saliva (2 h; 37 degrees C). In both cases, the specimens were immersed in 1% citric acid (pH 3.6; 2 min; 25 degrees C). Calcium released from enamel (CaR) and its relative surface reflection intensity (%SRI) was measured after 5 cycles. Between-group differences were verified with two-way ANOVA, with presence of pellicle and treatment as factors (alpha = 0.05). Results: The presence of pellicle provided better protection regarding %SRI (p < 0.01), but not regarding CaR (p = 0.201). In relation to treatment, when compared to the control group, all proteins/peptides provided significantly better protection (p < 0.01 for %SRI and Car). The combination of all three proteins/peptides demonstrated the best protective effect (p < 0.01 for %SRI). Conclusion: Depending on the protein or peptide, its erosion-inhibiting effect derives from their interaction with the enamel surface or from modifying the pellicle, so a combination of proteins and peptides provides the best protection. Clinical significance: The present study opens a new direction for a possible treatment with a combination of proteins for native human enamel, which can act directly on the enamel surface as well on the modification of the salivary pellicle, for the prevention of dental erosion. Univ Fed Sao Carlos, Dept Genet & Evolut, Sao Carlos, SP, Brazil Univ Sao Paulo, Bauru Sch Dent, Dept Biol Sci, SP Al Octavio Pinheiro Brisolla 9-75, BR-17012901 Bauru, SP, Brazil Univ Bern, Sch Dent Med, Dept Restorat Prevent & Pediat Dent, Bern, Switzerland Univ Estadual Paulista, Chem Inst, Araraquara, SP, Brazil Univ Estadual Paulista, Chem Inst, Araraquara, SP, Brazil FAPESP: 2019/08437-5

Objectives The aim of this in vitro study was to examine the effect of different levels of magnification on the accuracy and reliability of visual caries detection using ICDAS criteria. Methods Occlusal surfaces of 100 extracted molars were assessed by 14 examiners (3rd and the 4th year dental students and dentists) using no magnification aids, a 2.5× Galilean loupe, a 4.5× Keplerian loupe, or a surgical microscope with 10× magnification. The assessments were repeated on a different day. Sensitivity, specificity, AUC and reliabilities were calculated according to the gold standard of histology. Results We found that with increasing magnification, the number of surfaces rated as “sound” (ICDAS code 0) decreased, while the number of surfaces with a localized enamel breakdown (ICDAS code 3) increased. While the sensitivities increased, the values of the specificities decreased to an unacceptably low level irrespective of the clinical experience of the examiners. Conclusions ICDAS seems to be optimized for natural vision up to 2.0× magnification and not for high magnifications. The use of powerful magnification in visual caries detection involves the risk of unnecessary and premature invasive treatment. Clinical significance This paper discusses when it does and does not make sense to use magnification devices for visual caries detection using ICDAS criteria. Strong magnifications should be refrained from for this purpose.

Objectives This in vivo study compared the protein profile of the acquired enamel pellicle (AEP) in volunteers 1) with gastroesophageal reflux disease (GERD) and erosive tooth wear (ETW) (BEWE ≥ 9; GE group); 2) with GERD without ETW (BEWE = 0; GNE group) and 3) control (without GERD and BEWE = 0; C group). Materials and methods Twenty-four subjects (8/group) participated. AEP was formed during 120 min and collected. After protein extraction, the samples were submitted to reverse phase liquid chromatography coupled to mass spectrometry. Label-free proteomic quantification was performed using Protein Lynx Global Service software. Results In total, 458 proteins were identified. Seventy-six proteins were common to all the groups. The proteomic profile of the AEP was quite different among the distinct groups. The numbers of proteins exclusively found in the C, GE and GNE groups were 113, 110 and 81, respectively. Most of the proteins exclusively identified in the C and GNE groups bind metals, while those in the GE group are mainly membrane proteins. Many proteins were found exclusively in the reflux groups. In the quantitative analyses, when the GNE group was compared with the GE group, the proteins with the highest decreases were Lysozyme C, Antileukoproteinase, Cathepsin G, Neutrophil defensins and Basic salivary proline-rich proteins, while those with the highest increases were subunits of Hemoglobin, Albumin and isoforms of Cystatin. Conclusion Profound alterations in the proteomic profile of the AEP were seen in GNE compared with GE volunteers, which might play a role in the resistance to ETW seen in the first. Clinical significance This pioneer study compared the proteomic profile of the AEP of patients with GERD with or without ETW. Increased proteins in those without ETW might be protective and are good candidates to be added to dental products to protect against erosion caused by intrinsic acids.

OBJECTIVE To investigate how the modulus of elasticity of resin composites influences marginal quality in restorations submitted to thermocyclic and mechanical loading. METHODS Charisma, Filtek Supreme XTE and Grandio were selected as they were found to possess different moduli of elasticity but quite similar polymerization contraction. MOD cavities (n=30) were prepared in extracted premolars, restored and then subjected to thermocyclic and mechanical loading. Marginal quality of the restorations before and after loading was analyzed on epoxy replicas under a scanning electron microscope. The percentage of gap-free margins and occurrence of paramarginal fractures were registered. Modulus of elasticity and polymerization contraction were analyzed with parametric and margins with nonparametric ANOVA and post hoc Tukey HSD or Wilcoxon rank-sum tests, respectively. The number of paramarginal fractures was analyzed with exact Fisher tests (α=0.05). RESULTS Grandio demonstrated significantly more gap-free enamel margins than Charisma and Filtek Supreme XTE, before and after loading (p 0.05). No significant effect of resin composite (p=0.81) on the quality of dentine margins was observed, before or after loading. Deterioration of all margins was evident after loading (p

Objectives To compare the performance of LFpen (DIAGNOdent pen) with two different wedge-shaped tips to conventional bitewing radiography (BW) for detecting proximal secondary caries at the cervical margin of amalgam restorations in vitro. Methods Seventy-five molars with class II amalgam restorations were selected. Depending on the marginal filling extension, data was subdivided into a crown group (C), when the filling ended in enamel, and into a root group (R), when the filling ended beyond the cementum-enamel junction. Bayesian analysis including calculation of the area under the receiver operating curve (AUC) was performed. Furthermore, Spearman correlations between caries and cofactors, such as presence of plaque or stain, occlusal ditching, marginal gap size, filling overhangs, and shortfalls, were calculated. Additionally, for group R the correlation coefficient between LFpen measurements and lesion depth was calculated. Histology served as gold standard. Results In group C both at the D1 and D3 levels, LFpen with two different tips showed a better performance than bitewing radiography (AUC at D1: 0.83/0.79 (LFpen) and 0.63 (BW); at D3: 0.66/0.66 (LFpen) and 0.53 (BW)). In group R, the respective AUC values were 0.53/0.56 (LF) and 0.59 (BW). A significant medium correlation was observed for occlusal ditching and proximal caries. Stain accumulation at the restoration margins especially in combination with filling overhangs interfered with LFpen readings, resulting in false positive measurements. Conclusions Compared to BW, LFpen enhances the detection of secondary caries lesions at the cervical margin of amalgam restorations that do not extend below the cementum-enamel junction.

OBJECTIVES: To determine the clinical performance of a laser fluorescence device (DIAGNOdent pen, KaVo) to discriminate between different occlusal caries depths (D(0)-D(1-4); D(0-2)-D(3,4)) in permanent molars. METHODS: In this prospective, randomized two-centre-study 120 sound/uncavitated carious sites in 120 patients were measured after visual and radiographic caries assessment. In cases of operative intervention (n=86), the lesion depths after caries removal were recorded (reference). In cases of preventive intervention (n=34), the sites were reassessed visually/radiographically after 12 months to verify the status assessed before (reference). The discrimination performance was determined statistically (Mann-Whitney test, Spearman's rho coefficient, and areas under the receiver operating characteristic curves (AUCs)). Sensitivities (SE) and specificities (SP) were plotted as a function of the measured values and cut-off values for the mentioned thresholds suggested. RESULTS: Sound sites (n=13) had significantly minor fluorescence values than carious sites (n=107) (P

The new device DIAGNOdent pen based on red laser light induced fluorescence was introduced for the detection of approximal and occlusal caries. The aim of this study was to test its performance on occlusal surfaces. The new device comes with two different sapphire fibre tips: a cylindrical tip and a conical tip. The two new sapphire fibre tips were used and compared with the tip currently available with DIAGNOdent (DD). Methods The teeth were selected from a pool of extracted permanent human molars, which were stored frozen at −20 °C, until use. Prior to being measured the teeth were defrosted and cleaned. One hundred and nineteen teeth were selected and measured with the old tip and with the two new tips of the new device by two independent assessments. The teeth were histologically prepared and assessed for caries extension. Results Specificity values for D1, D2 and D3 ranged between 0.69 and 0.89, sensitivity between 0.78 and 0.96. There were no statistically significant differences obtained between the two tips of the new and the one tip of the old device (p > 0.05). Intra-examiner reliability with kappa values of >0.83 was high. Conclusions In this study, the new laser fluorescence device performed on occlusal surfaces as well as the available device.

Objectives . To determine the amount of damage to adjacent surfaces during cavity preparation of approximal box-cavities by using either no magnification or an individually adapted surgical telescope. Materials and Methods . Nine dentists prepared in a mannequin head 4 approximal (class II) box-cavities without magnification using a high speed handpiece with lighting from a dental unit. At least 2 months later the test was repeated with a surgical telescope system with integrated light. The degree of damage the 72 adjacent surfaces suffered was determined. Results . The average time needed to prepare one cavity was 14.9 min without and 18.3 min with magnification ( p =0.01). Altogether, 29.7% of adjacent area were damaged when no surgical telescopes were used and 34.5% when surgical telescopes were applied ( p >0.05). When the mesial-facing and distal-facing surfaces were analysed independently a statistically significant increase of damage was found on distal surfaces ( p =0.03) when using surgical telescopes. Seventy surfaces (=97%) had a preparation trauma. Conclusions . Surgical telescopes do not decrease damage of adjacent tooth surfaces.

Objectives The study investigated the modification of composite-to-enamel bond strength by pre-treatment of enamel with a concentrated, acidic SnCl 2 -solution. Methods Six groups of flat human enamel specimens ( n = 44 per group) were treated as follows: OB-H: H 3 PO 4 etching, Optibond FL application (primer + adhesive; manufacturer's instructions); OB-S: SnCl 2 pre-treatment, Optibond FL application (primer + adhesive); OB-HS: H 3 PO 4 etching + SnCl 2 pre-treatment, Optibond FL application (primer + adhesive); CF-N: Clearfil SE application (primer + bond; manufacturer's instructions); CF-H: H 3 PO 4 etching, Clearfil SE application (primer + bond); CF-S: SnCl 2 pre-treatment, Clearfil SE application (primer + bond). Enamel specimens were then built up with resin composite (Clearfil Majesty Esthetic) and stored (100% humidity, 37 °C, 1 week). μTBS-measurement and failure mode analysis of one-half of the specimens were performed immediately after storage, while the other half was analysed after a thermocycling procedure (8500 cycles; 5 °C and 55 °C; dwell time 30 s). Additional specimens were prepared for SEM- and EDX-analysis. Results Highest values were measured for OB-H before and after thermocycling, lowest values for CF-N. Compared to OB-H treatment, OB-S treatment reduced μTBS before/after thermocycling by 23%/28% and OB-HS treatment by 8%/24% (except for OB-SH before (n.s.), all p ≤ 0.001 compared to OB-H). In the Clearfil SE treated groups pre-treatment increased μTBS significantly compared to CF-N (before/after: CF-H: +46%/+70%; CF-S: +51%/42%; all p ≤ 0.001). Conclusion Pre-treatment with H 3 PO 4 or SnCl 2 markedly increased the μTBS of Clearfil SE to enamel. However, thermocycling partly reduced the gain in μTBS obtained by SnCl 2 pre-treatment. Clinical significance The application of an acidic and highly concentrated SnCl 2 solution is a good option to increase the μTBS between enamel and a resin composite mediated by an adhesive system containing the multifunctional monomer MDP.

a b s t r a c t Objectives: Application of the recently developed optical method based on the monitoring of the specular reflection intensity to study the protective potential of the salivary pellicle layer against early enamel erosion. Methods: The erosion progression was compared between two treatment groups: enamel samples coated by the 15 h-in vitro-formed salivary pellicle layer (group P, n = 90) and the non-coated enamel surfaces (control group C, n = 90). Different severity of the erosive impact was modelled by the enamel incubation in 1% citric acid (pH = 3.6) for 2, 4, 8, 10 or 15 min. Erosion quantification was performed by the optical method as well as by the microhardness and calcium release analyses. Results: Optical assessment of the erosion progression showed erosion inhibition by the in vitro salivary pellicle in short term acidic treatments (4 min) which was also confirmed by microhardness measurements proving significantly less ( p < 0.05) enamel softening in the group P at 2 and 4 min of erosion compared to the group C. SEM images demonstrated less etched enamel interfaces in the group P at short erosion durations as well. Conclusions: Monitoring of the specular reflection intensity can be successfully applied to quantify early erosion progression in comparative studies. In vitro salivary pellicle (2 h) provides erosion inhibition but only in short term acidic exposures. Clinical significance: The proposed optical technique is a promising tool for the fast and noninvasive erosion quantification in clinical studies.

Objectives: This in vitro study aimed to investigate the protective effect of four commercial novel agents against erosion. Methods: Ninety human molars were distributed into 9 groups, and after incubation in human saliva for 2 h, a pellicle was formed. Subsequently, the specimens were submitted to demineralization (orange juice, pH 3.6, 3 min) and remineralization (paste slurry containing one of the tested novel agents, 3 min) cycles, two times per day, for 4 days. The tested agents were: (1) DenShield Tooth; active ingredient: 7.5% W/W NovaMin® (calcium sodium phosphosilicate); (2) Nanosensitive hca; active ingredient: 7.5% W/W NovaMin®; (3) GC Tooth Mousse; active ingredient: 10% Recaldent™ (CPP-ACP); (4) GC MI Paste Plus; active ingredients: 10% Recaldent™, 900 ppm fluoride. Two experimental procedures were performed: in procedure 1, the tested agents were applied prior to the erosive attack, and in procedure 2 after the erosive attack. A control group receiving no prophylactic treatment was included. Surface nanohardness (SNH) of enamel specimens was measured after pellicle formation and after completion of daily cyclic treatment. Results: SNH significantly decreased at the end of the experiment for all groups (p < 0.05). In both procedures, there was no statistically significant difference between the control group and those treated with paste slurries (p > 0.05). In addition, the changes in SNH (ΔSNH = SNHbaseline − SNHfinal) did not show statistically significant difference between both procedures (p > 0.05). Conclusion: Tooth erosion cannot be prevented or repaired by these novel agents, regardless of fluoride content.

OBJECTIVES: The aim of this randomised clinical trial was to investigate if a laser fluorescence device is able to discriminate between sound and carious approximal sites and between enamel and dentinal lesions, as well as to find appropriate cut-off values. METHODS: One hundred and seventeen sound or uncavitated carious sites in permanent molars were visually and radiographically examined, then either opened or not, after which their laser fluorescence was measured. Forty-three lesions were opened, the caries removed and the clinically identified caries depths were registered in addition to the radiographical scoring. Seventy-four sites were radiographically deemed sound or had enamel caries and were not opened. Here, the radiographical scorings were registered. RESULTS: Taking the radiographic scoring as gold standard for all investigated approximal sites, sound sites (D(0), n=40) showed significantly lower laser fluorescence measurements than carious sites (D(1-4), n=77) (Mann-Whitney test, P

Objectives The aim of this study was to evaluate the cavitation rate of proximal caries using different magnification aids in vitro. Methods Radiographs of 285 extracted teeth were taken and the proximal surfaces were graded to the criteria R0 (no radiolucency), R1 (radiolucency confined to the outer half of enamel), R2 (inner half of enamel) and R3 (outer half of dentin). Subsequently, the proximal surfaces were checked for the presence of cavitations with the naked eye (NE), and by using 4.3× magnification eyeglasses (ME), a stereo microscope (SM, 10×), or a scanning electron microscope (SEM, up to 2000× magnification). Results In surfaces with R3 caries, cavitations were visible in 56 of 59 cases with the naked eye. When using SEM, all surfaces revealed cavitations (100%). Regarding the surfaces with R2 lesion, 36 of 46 cases showed cavitations (NE); the corresponding values were 39/46 (ME), 41/46 (SM), and 46/46 (SEM); in the latter, in most cases deep defects could be observed. With regard to R1 lesions, 36/60 (NE), 43/60 (ME), 45/60 (SM), and 58/60 (SEM) cases revealed cavitations. A breakdown of radiographically sound surfaces (R0) was present in some 10% of the examined surfaces (24/261, NE; 33/261, SEM). Conclusions Cavitations (defined as breakdown of the surface) are present in significantly more cases than previously reported. This might be an explanation why even small radiolucencies tend to progress, albeit slowly. Thus, close follow-ups should strongly be recommended when considering a preventive treatment regimen with small radiolucencies.

OBJECTIVES AND METHODS: This study investigated the sealing ability of a current available unfilled fissure sealant applied over sound (n=80), artificially created (n=80) and naturally carious fissures (n=80) under different humidity conditions (90+/-2 and 45+/-2% relative humidity) and etching times (40 and 60s). All samples were submitted to 5000 thermal cycles and examined by light microscopy after sectioning. Microleakage, penetration ability, fissure type, fissure entrance angle, sealant occlusal length, caries location and caries depth were assessed. RESULTS: The significantly longer sealant occlusal length and larger entrance angle exhibited by shallow fissures, contributed to their higher microleakage and smaller amounts of unfilled areas compared to deep fissures. Sealant microleakage was significantly influenced by the condition of the enamel (sound, artificial and natural caries) and the caries location in the fissures, but not by enamel caries depth (D1 and D2), etching time, or humidity condition. Natural caries exhibited significantly higher microleakage than sound or artificially created carious fissures. CONCLUSIONS: Based on the results of this study, it can be concluded that location of caries in the fissure rather than its depth should be taken into account when applying a fissure sealant. When the borders of the fissure sealant are on carious enamel, a significantly higher microleakage must be expected. The artificial caries model was not a suitable method to assess the behavior of natural fissure caries.

Objectives: Cutting and finishing approximal preparations with conventional instrumentation and methods may produce iatrogenic damage in adjacent tooth surfaces which subsequently requires restoration. The objective of this investigation was to determine the occurrence of iatrogenic damage and whether, under everyday working conditions in dental practice, such damage could be reduced significantly by using an alternative method and instrumentation designed especially for the purpose. Methods: Dental practitioners were asked to take impressions of teeth scheduled for Class II amalgam restorations. One group (control) prepared the teeth with conventional rotary instrumentation (n = 71), while the test group used a new method and instrumentation (n = 63). These comprised a set of files, a right-angle handpiece with reduced stroke, 36 fixed (rotation-locked) positions for the files and a cylindrical bur with a recessed front-end cutting suface. Damage to the adjacent teeth was assessed under a stereomicroscope. Results: Using conventional methods, all adjacent tooth surfaces showed damage, often exposing deep layers of dental tissues. There was a clinical and statistically significant reduction of incidence and severity of iatrogenic preparation trauma in the test group. Conclusion: It appears that conventional approximal box preparation results in significant damage to adjacent tooth surfaces. With the system tested, damage to adjacent tooth surfaces during preparation of proximal boxes can be significantly reduced. This should have an impact on the subsequent rate of restoration for the adjacent surfaces.