In vivo validation of Diagnodent and Vista proof devices vs ICDAS clinical criteria on incipient carious lesions in adults.

AIM: This study aimed to validate the in vivo performance of Diagnodent and Vista proof devices with ICDAS clinical criteria on incipient carious lesions in adults. METHODS: A total of 44 adult patients with 230 incipient occlusal caries took part in the present study. These patients were assessed for caries with ICDAS clinical criteria, and then they were examined with Diagnodent pen™ (DP) and Vista proof™ (VP) fluorescence devices. Sensitivity, specificity accuracy, and ICC agreement between devices with ICDAS criteria, which served as a gold standard, were evaluated. RESULTS: Regarding the caries diagnostic devices, sensitivity and specificity found 0,61 and 0,51 for DP, and 0,64 and 0,54 for VP, respectively. The different detection methods showed no differences in diagnostic capacity (Az values) each other, and ICC values with ICDAS criteria were calculated low. CONCLUSIONS: DP and VP do not contribute to incipient occlusal carious lesions' better detective ability compared with visual ICDAS clinical criteria. The DP and VP devices presented no differences in diagnostic ability and measured lesion depth concerning the visual examination.

Clinical Evaluation of Two Different Prevention Programs in Adults Depending on Their Caries Risk Profile: One-year Results.

The aim of this study was to investigate the management of incipient caries lesions in adults with two preventive protocols. A total of 44 adult patients with high, moderate and low caries risk with 516 incipient caries took part in the study. These patients were assessed for caries with International Caries Detection and Assessment System (ICDAS) criteria and were then divided into three groups depending on their caries risk profile: a high-risk group (group A), a moderate-risk group (group B), and a low-risk group (group C). Participants in each group were further divided randomly into two subgroups. In subgroups A1, B1, and C1, an intensive preventive protocol was applied, while in subgroups A2, B2, and C2, the protocol consisted only of instructions in oral hygiene. The invasive-intensive protocol included the topical application of fluoride, brushing with 5000-ppm fluoride toothpaste, use of amorphous calcium phosphate-casein phosphopeptide, applications of sealants for occlusal lesions (ICDAS code 2), and minimal resin restorations for occlusal lesions (ICDAS code 3). There was no statistically significant difference in the number of lesions (baseline and after one year) in the high-risk and moderate-risk groups that received the intensive protocol (groups A1 and B1), while the control groups were statistically significant different (groups A2 and B2). In the low-risk group, there was no statistically significant difference in the number of lesions (groups C1 and C2). The two different preventive protocols in the high- and moderate-risk groups presented differences in effectiveness, while in the low-risk group, no significant difference was demonstrated.

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.

Evaluation of a blended learning course for teaching oral radiology to undergraduate dental students.

AIMS: The purpose of this study was to develop and implement a blended course (a combined face-to-face and online instruction) on undergraduate oral radiology and evaluate it by comparing its educational effectiveness (derived from students' performance and answers to questionnaires) to a conventional course's. Students' attitudes concerning the blended methodology were also registered. METHODOLOGY: An original course was developed and implemented, and its electronic version was uploaded to an e-learning educational platform. The course was attended by two groups of final-year students, who were taught by either the conventional face-to-face methodology or the blended learning methodology. Students answered a series of questionnaires, before and after following the course, regarding their perceptions, attitudes and evaluation of the course. Additionally, they completed knowledge assessment tests and their grades (before and after the course) were compared. Educational effectiveness of the course was determined by analysing the results of the questionnaires and the tests. RESULTS: Students in the blended group performed significantly better than their colleagues of the conventional group in the post-course knowledge test, and female students of the blended group performed better than male students. Students evaluated high the course content, organisation, educational material, and the blended group students additionally appreciated the course design and clarity of instructions. Students' attitudes towards elements of blended learning (effectiveness, motivation and active engagement) were very positive. Most of the blended group students, who attended the face-to-face meeting (approx. 91%), evaluated it as helpful for summarising the subject and clarifying difficult issues. CONCLUSIONS: Blended learning is effective and well evaluated by dental students and can be implemented in undergraduate curriculum for teaching oral radiology.

A survey on education in cariology for undergraduate dental students in Europe.

The aim of the survey was to collect relevant information about education in cariology for dental undergraduate students in Europe. The ORCA/ADEE cariology curriculum group prepared a questionnaire that was mailed in 2009 to 179 European dental schools. One hundred and twenty-three dental schools (72%) from 32 countries completed and returned the questionnaires. In most of these schools, education in cariology is delivered by at least two different units. The units mainly involved are Paediatric Dentistry, Conservative Dentistry, Restorative Dentistry or Operative Dentistry. Theoretical education in cariology is delivered by practically all responding dental schools, and in 96% of these schools, it starts within the first 3 years. Pre-clinical exercises are offered by 98% of the schools starting mainly in the third or fourth year. In 97% of the schools, clinical exercises are carried out, and this occurs mainly in the fourth and fifth year. In nearly all dental schools (88%), education in cariology comprises not only caries but also dental erosion and non-erosive wear. The vast majority of the responding dental schools (89%) supported the idea of developing a European Core Curriculum in Cariology.

Effect of fluoride and of calcium sodium phosphosilicate toothpastes on pre-softened dentin demineralization and remineralization in vitro.

OBJECTIVES: The purpose of this in vitro study was to evaluate the effect of toothpastes containing sodium fluoride in different concentrations or a calcium sodium phosphosilicate system on pre-softened dentin demineralization and remineralization. METHODS: During a ten day pH-cycling protocol, pre-softened bovine root dentin slabs were immersed twice daily, after the demineralization periods, for 2min, in the following toothpaste slurries: (a) non-fluoridated (control), (b) 7.5% calcium sodium phosphosilicate, (c) 1450 ppm F, (d) 2800 ppm F and (e) 5000 ppm F. Subsequently, the specimens were subjected to a 15-h acid resistance test. Surface microhardness was assessed initially and during the pH-cycling and the acid resistance test period. Repeated measurements in each group were analyzed through appropriate regression models for longitudinal data. RESULTS: All fluoride groups, during pH cycling, showed significantly less microhardness loss (p < or = 0.010, p < or = 0.002, p < or = 0.002) and subsequently exhibited increased acid resistance (p < or = 0.010, p < or = 0.001, p < or = 0.001) compared to the control. The 5000 ppm and 2800 ppm F toothpastes, inhibited demineralization significantly more effectively than the 1450 ppm F (p < or = 0.001, p < or = 0.030) and the calcium sodium phosphosilicate toothpaste (p < or = 0.001), while no significant differences were found between the two high fluoride groups (p=0.130). The calcium sodium phosphosilicate toothpaste, during pH cycling showed a difference that approached statistical significance compared to control (p=0.079), but its acid resistance behavior was similar to control (p=0.610). CONCLUSIONS: Under these experimental conditions, the high fluoride toothpastes promoted remineralization and inhibited demineralization more effectively, than the 1450 ppm F, the non-fluoridated (control) and the calcium sodium phosphosilicate toothpastes.

Dental data of the Athens 2004 Olympic and Paralympic Games.

The Athens University, School of Dentistry, accepted the challenge to organize the Dental Health Services in the Athens 2004 Olympic and Paralympic Games in order to provide the best quality of oral health services to the athletes, coaches, escort members and Olympic Village personnel. Data from the whole activity protocol of the Athens 2004 Games Dental Health Services - the reception, admission and treatment protocols, the facilities and the infrastructure, the number of cases treated per specialty and the experience gained - were recorded. During the Olympic Games, there were more than 1400 dental cases in more than 650 patients, elite athletes, escort members, coaches and staff of the Olympic Village. Among them 313 fillings, 100 root canal therapies, 57 mouthguards and 9 dental trauma cases were treated. During the Paralympic Games, there were more than 240 dental cases in more than 220 patients. Among them 73 fillings, 12 root canal therapies, 21 extractions and 3 dental trauma cases were treated. In such events, highly trained dentists are needed and if possible, specialized in operative dentistry or endodontics. The role of team dentist seems to be of great importance.

The effect of sterilization methods on the light transmission characteristics and structure of light-curing tips.

The purpose of this study was to investigate the effect of various sterilization methods on the light transmission and the structural characteristics of two light-curing tips. Twenty tips from two light-curing devices [Elipar II (EL) and Heliolux II (HL)] were classified into four groups. The tips in groups A to C were subjected to sterilization with 0.2% sodium dichloroisacyanurate solution (Presept), 2% glutaraldehyde solution (Cidex) (2 h cycle(-1)) and water-steam autoclave (120 degrees C, 1 bar, 12 min cycle(-1)), respectively. A total of 2100 sterilization cycles was performed for all methods tested. The transmitted light intensity (TLI) was measured at specific sterilization time intervals by a curing radiometer (Model 100, Demetron). The final % TLI reduction of the sterilized tips was calculated relative to the corresponding control ones. The topography and composition of the front curing tip surfaces were determined using scanning electron microscopy combined with electron probe microanalyser. Autoclaving caused the lowest final TLI decrease (EL: 15%, HL: 19%) compared with Presept (EL: 60%, HL: 42%) and with Cidex (EL: 68%, HL: 52%). Cidex yielded higher TLI drop than Presept for both types of tips examined. Elipar tips were found to be more sensitive than Heliolux tips to both chemical sterilization techniques. Total or partial coating of the tip surfaces with insoluble salts after sterilization with Presept and Cidex was detected, mainly composed of Ca, Cl, Al, Pd and Mg traces. No changes were noted on the surfaces after autoclave. Water-steam autoclave is safer than the 0.2% sodium dicloroisocyanorate and 2% glutaraldehyde chemical sterilization agents regarding the light transmission characteristics and the structure of the light-curing tips.

Heterogeneous distribution of single-bottle adhesive monomers in the resin-dentin interdiffusion zone.

OBJECTIVES: The purpose of this study was to investigate whether monomer separation occurs in single-bottle adhesives applied on acid-etched dentin surfaces. METHODS: Smear-layer covered dentin specimens produced from sound premolars, were acid-etched and analyzed by micro-MIR FTIR spectroscopy, before and after treatment with the single-bottle adhesives One-Step, Prime and Bond 2.1, Scotchbond 1 and Syntac-Sprint. The difference spectra (etched, and primed minus etched of the same dentin surfaces) were plotted and compared with original adhesive spectra. The C=C/C...C (aromatic adhesives) and C=C/C=O (aliphatic adhesives) peak area ratios were used to evaluate the extent of monomer separation relative to original adhesive spectra at the uppermost 2 microm of the resin-dentin interdiffusion zone. Three dentin specimens were used for each adhesive. One-way ANOVA and Newman-Keuls tests were performed to assess the statistically significant differences (alpha=0.05). RESULTS: All the adhesives demonstrated separation of monomer components on etched dentin ranging in mean values from 68.7 to 81.9% relative to reference. High molecular weight hydrophobic (i.e. BisDMA, BisGMA, BisGMA adducts) and hydrophilic monomers (i.e. BPDMA) predominated at the region probed. Prime and Bond 2.1 demonstrated the highest extent of monomer separation. SIGNIFICANCE: Heterogeneous monomer distribution following application to etched dentin may affect the curing performance of single-bottle adhesives within the resin infiltrated region and consequently, the mechanical and chemical stability of the network formed.

Effect of dentin primers on the morphology, molecular composition and collagen conformation of acid-demineralized dentin in situ.

OBJECTIVES: The purpose of this study was to assess the effect of two commercial primers and distilled water on the morphology, molecular composition and collagen conformation of acid-demineralized dentin in situ. METHODS: Dentin specimens etched with Scotchbond Etchant were imaged by tapping mode AFM and analyzed by MIR-FTIR spectroscopy. They were then primed with Scotchbond Multi-Purpose Plus Primer, Scotchbond 1 Adhesive or distilled water and imaged and analyzed again. The chemical modifications induced on the uppermost 2 microns of primed dentin were studied after water and original primer subtraction. The conformational changes of type I collagen at this region were evaluated by deconvoluting the amide I band components. The absorbance ratio An(1655/1627) was used to semiquantitatively assess, on a relative basis, the extent of collagen denaturation. RESULTS: All the priming treatments swelled the collapsed dentin collagen left after etching. No evidence of primary bonding was found after priming treatments, while approximately 50% of the conditioned dentin collagen appeared denatured. Treatment with distilled water did not change the status of denatured collagen, however, application of the commercial primers refolded the alpha-helix to approximately 95% of the extent found on the native reference dentin. SIGNIFICANCE: The dynamic response of dentin collagen to demineralization and priming treatments reveals the critical role of some primers in rapidly restoring the conformational status of acid-denatured collagen. Implementation of reactive adhesive groups in alpha-helix recovery may provide an associative means of modifying the mechanical properties of the demineralized collagen based on the extent of their intermolecular bonding.

Effect of acidic conditioners on dentin morphology, molecular composition and collagen conformation in situ.

OBJECTIVE: The aim of the study was to evaluate the effect of some acidic conditioners on dentin morphology, molecular composition and collagen conformation in situ. METHODS: Smear layer-covered dentin specimens prepared from third molars immediately after extraction were imaged by tapping made AFM and analyzed by MIR-FTIR spectroscopy. The same specimens were subjected to conditioning treatments with CA Agent (Kuraray), Scotchbond Etchant (3M Dental Products) and Scotchbond MP Etchant (3M Dental Products) gels and then imaged and analyzed again. The extent of dentin decalcification at the uppermost 2 microns region was calculated from the percentage reduction in the-PO4/amide I peak area ratio of conditioned specimens relative to their individual smear layer-covered references. These results were compared by ANOVA and Scheffé statistical analyses. The conformational changes of dentin type I collagen at the region were studied qualitatively by deconvoluting the amide I bands of MIR-FTIR spectra and assigning the band components to carbonyl hydrogen bonding states related to the alpha-helix structure. RESULTS: All the conditioners removed the smear layer, funneled the tubules, increased the intertubular roughness and contaminated the dentin surfaces with residues from irreversibly adsorbed thickening agents. Conditioned dentin surfaces showed a reduction in orthophosphates and carbonates and an increase in amide I, II and III groups. CA Agent manifested a significantly lower extent of dentin decalcification than Scotchbond etchants (p < 0.05). Collagen conformational changes involved a decrease in intermolecular hydrogen bonded amide I carbonyls associated with the alpha-helix structure and enhancement of imide carbonyls hydrogen bonded to water, which suggest collagen denaturation. SIGNIFICANCE: Apart from dentin decalcification, the acidic conditioners induced considerable changes on dentin collagen conformation mostly associated with denaturation processes. In addition, irreversibly adsorbed residual thickeners substantially modified the morphology and composition of dentin surfaces. These findings show the complex interaction pathways between conditioners and dentin surfaces and the great potential of modern in situ imaging and analysis techniques in probing these interactions.

In vivo corrosion behavior of gold-plated versus titanium dental retention pins.

Two types of titanium dental retention pins and a gold-plated stainless steel pin were tested for their in vivo corrosion behavior. Six paired samples of titanium and gold-plated pins were placed in box preparations of 12 periodontally involved premolars. Half of the samples were restored with a high copper admixed type amalgam while the rest were restored with a BisGMA-POCl2 bonding resin and a hybrid visible light-cured composite resin. After 3 months in vivo, the teeth were extracted, and the pins were removed and examined with an electron microprobe. The surface of the titanium pins was found to be smooth and without defects. Only traces of Ca and P could be identified from dentin. The gold-plated pins demonstrated cracks and pores, especially at the outer part of the serrations, resulting in disruption of the electroplated film. Traces of Hg, Sn, Cu, S, Zn, Ca, K, Cl, P, and S were detected at the gold-plated pin/amalgam interface, while Cl and P were found at the gold-plated pin/composite resin interface. The in vivo corrosion resistance of the titanium pins was found to be superior to that of the gold-plated stainless steel pins.

Surface alterations on dental restorative materials subjected to an air-powder abrasive instrument.

This study assessed the effect of an air-powder abrasive instrument (Prophy Jet) on the surface integrity of a series of restorative materials. Four types of amalgam alloys (Amalcap, Dispersalloy, Tytin, Ana 2000), three types of composite resins (Silux, Brilliant Lux, Adaptic II), a heat-cured resin (SR Vivadent), and porcelain (Vita VMK) fused to a Gr-Ni alloy at 1 mm and 2.5 mm thickness were subjected from 5 mm distance to the abrasive stream at 100 psi for 5 seconds. The resulting surface topography was studied under an electron probe microanalyzer. All of the amalgams presented increased surface roughness and alterations in the surface composition assigned to the destruction of the soluble gamma-2 and n phases. Composite resins showed excessive matrix disruption, exposure of the filler particles and pitting on the prepolymer surfaces. The crown and fixed partial denture resin was the most affected material. Porcelain at 2.5 mm thickness exhibited moderate stain pitting, whereas in 1 mm thickness severe glaze cracking was identified.

[Crack path in dental amalgams]. / E poreia ton rogmon sta odontiatrika amalgamata.

The need of amalgam to resist fracture becomes a more evident necessity when restoration margins are taken into consideration. Marginal microcracks permit bacteria to pass beneath the restoration resulting in cement base dessalution, secondary caries and pulp inflammation. Fracture toughness of amalgam is usually studied indirectly from the maximum force required to fracture the amalgam, during compressive, tensile or bend stresses, through its ability to deform plastically or its surface hardness. Important information on fracture toughness of amalgams can be also taken from metallographic studies of their microstructures, during or after the formation of a crack. This study was planned to evaluate the microcracks produced on the surface of different amalgams, with a Vickers pyramid head of a hardness tester and their relation to the different phases of the amalgam structure. Seven amalgams were studied: Amalcap-F, Tytin, Cupralloy, Ana-2000 and three experimental combinations of them, in order to have in the same amalgam different alloy particles, for evaluation purposes. The result showed that the structure elements, that mainly assist crack formation and propagation, are voids and gamma 2-phase, while elements that resist fracture are alloy particles (gamma-phase) in conventional amalgams, eutectic spheres in admixed high copper amalgams and eta'-phase crystals in single melt high copper amalgams.

[Composite resin inlays and onlays]. / Hentheta kai epentheta apo synthete retine.

The establishment and development of composite resins has led to their use as a posterior restorative material. Although posterior composites have evolved considerably, both clinical studies and experience have confirmed that several problems still remain concerning their clinical properties and the relative complexity of handling the material. In order to resolve these problems, two different manufacturers have introduced composite resin systems for the fabrication of direct or indirect resin inlays and onlays which are cemented into the acid-etched preparation with a modified composite resin. Both systems are based on the same concept: the polymerization of the resin takes place out of the mouth in a special oven where a specific heat-curing procedure is followed. There is an essential difference between the two systems. When the direct resin system is used, the inlay is formed and partly light-cured into the tooth preparation, then it is removed for further polymerization. When the indirect system is used the procedure takes place in the lab where the inlay is formed on the die. This article presents both systems, the step-by-step procedure that has been followed in several clinical cases as well as their advantages and disadvantages.

Surface reactions of adhesives on dentin.

The purpose of this study was to characterize changes in the surface chemistry of dentin following various adhesive treatments. The coronal parts of sound freshly extracted third molars were cross-sectioned over the pulp chambers, each producing a pair of dentin samples which were polished to 600 grit and cleaned with 3% H2O2. The first sample of each pair was used as a control, while the second one was subjected to one of the following adhesive treatments: (a) Gluma Cleanser, (b) Tenure Conditioner, (c) Scotchprep, (d) Gluma Cleanser/Gluma Primer, (e) Tenure Conditioner/Tenure Solution A&B, or (f) Scotchprep/Scotchbond 2 Adhesive. The treated samples paired with their respective controls were studied by small-area ESCA spectroscopy. Three areas of 1.0 mm in diameter randomly chosen on each sample were analyzed by survey and C1s, O1s, N1s high-resolution spectra. The samples from groups d, e, and f were additionally subjected to argon-ion-depth profiling of the uppermost 2-nm layer at 0.5-nm intervals. According to the results, treatment modes a, b, and c caused the reduction of carbonates and increased the -NH/NH2 ratio. Treatments a and c increased the alcohol groups, while treatments b and c increased the carbonyl and ether groups. All these changes were in comparison to the reference dentin specimens. Dentin treatment with d, e, and f induced a complex in depth distribution of the C, N, O binding states. The energy shifts detected do not indicate primary bonding of the tested adhesives to the dental substrate.

[Bonding of visible light cured composite resins to glass ionomer and Cermet cements]. / Synkratese photopolymerizomenon syntheton retinon se epiphaneies yaloionomeron kai keramometallikon konion.

The "sandwich" technique involves combination of composite resins to etched glassionomer cements, is used today in restorative dentistry. The purpose of this study is to evaluate the bond strength between several composite resins and glass ionomer or cerment cements. Cylindrical specimens of the cements Ketac-Silver, Ionobond and GC-Lining Ce-ment were inserted in a mold and their flat free surfaces were etched for 30". Cylindrical plastic tubes were set upon each one of these surfaces and filled with the Composite resins Durafill, Brilliant Lux, Estilux posterior, Estilux posterior CVS and Herculite XR. Half of the specimens transferred in tap water for 24 hours and the others after thermocycling in the first month, kept for 4 months. Shear bond strengths were determined in Monsanto Testing Machine and some fractured surfaces were examined under SEM. The results of this investigation indicate that this technique produces bond strengths between composite resins and glassioners and the combination type of resin and type of cement, affects the values of the strength. Glass cermeet--small particle resin provides the most effective strength and glass ionomer--microfill resins the least. Storage time and thermocycling don't significantly effect the bond strength. SEM examination showed that all fracture failures were obtained in the cement while the opposite resin surfaces were covered with particles of the cements.

[Microleakage pattern around posterior composite resin restorations, combined with a ceramometallic cement (sandwich technique)]. / Ergasteriake melete tes oriakes mikrodieisdyses gyro apo apokatastaseis me synthetes retines opisthion kai keramometallike konia se koilotetes B omadas.

The purpose of this in vitro investigation was to examine the degree of microleakage in class II, MOD, posterior composite resin restorations, in the distal wall of which a layer of 1,5 mm of ceramometallic cement was condensed. Conventional MOD cavities were prepared using 330 and 56 tungsten carbide burs in 20 premolars extracted for orthodontic reasons. In the first group (10 specimens) the gingival floor was located in the enamel, above the cementoenamel junction and in the second group the gingival floor was located below the CEJ. In the mesial box, cervically, a layer of 1,5 mm of ceramometallic cement (Ketac Silver) was condensed and etched with orthophosphoric acid 37%, the cavity was filled with posterior composite resin (Heliomolar, Vivadent) and 24 hours later the specimens were polished using Sof-Lex discs and thermocycled between 4 degrees C and 60 degrees C for 50 cycles of 2 minutes each. The specimens were immersed for 2 hours in 2% basic fuchsin solution, washed, cleaned with acetate solution and split in two halves longitudinally in a mesiodistal direction, using a hard tissue microtome. From the detection of the degree of dye penetration we conclude that: a) In the cervical walls located in cementum, where cermet cement was condensed, minimal dye penetration was detected b) In the opposite side, where the composite resin existed on dentin-cementum, the dye penetration is more severe c) Dye penetration in cavities located in the enamel, is moderate in the areas where cermet cement existed d) No dye was detected in the interface between cermet cement and posterior composite, in most specimens.

[A study of different polishing techniques for amalgams and glass-cermet cement by scanning electron microscope (SEM)]. / Melete technikon leianses amalgamaton kai mias keramometallikes konias se elektroniko mikroskopio saroses (SEM).

Finishing and polishing an amalgam restoration, is considered as an important and necessary step of the restorative procedure. Various polishing techniques have been recommended to success a smooth amalgam surface. The aim of this study was to investigate the influence of three different polishing treatments on the marginal integrity and surface smoothness of restorations made of three commercially available amalgams and a glass-cermet cement. The materials used were the amalgams, Amalcap (Vivadent), Dispersalloy (Johnson and Johnson), Duralloy (Degussa) and the glass-cermet Katac-Silver (ESPE). The occlusal surfaces of the restorations were polished by the methods: I) round bur, No4-rubber cup-zinc oxide paste in a small brush, II) round bur No 4-bur-brown, green and super green (Shofu) polishing cups and points successively and III) amalgam polishing bur of 12-blades-smooth amalgam polishing bur. Photographs from unpolished and polished surfaces of the restorations, were taken with scanning electron microscope, to evaluate the polishing techniques. An improvement of marginal integrity and surface smoothness of all amalgam restorations was observed after the specimens had been polished with the three techniques. Method II, included Shofu polishers, proved the best results in comparison to the methods I and III. Polishing of glass-cermet cement was impossible with the examined techniques.

[A comparative study of visible light units]. / Eugkritike melelte diaphoron syskeuon photopolymerismou syntheton retinon.

The purpose of this investigation was to examine the performance of 10 V.L.C. units according to the depth of cure of the composite resins by measuring the hardness difference (delta H) on the top and the bottom of cylindrical specimens 2.3 and 4 mm high. According to the results (a) there is a different performance between the units when the depth of cure exceeds the 2 mm (b) the type of composite resin (macrofille or microfille) has a significant influence of V.L.C. unit performance and (c) performance of the two types of V.L.C. units--with and without flexible photocolor--is almost the same.