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Dive into the research topics where Panagiotis Lagouvardos is active.

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Featured researches published by Panagiotis Lagouvardos.


Journal of Prosthetic Dentistry | 1996

Acrylic resin denture repair with adhesive resin and metal wires: Effects on strength parameters

Gregory L. Polyzois; A. G. Andreopoulos; Panagiotis Lagouvardos

The fracture of acrylic resin dentures is an unresolved problem in prosthodontics. In this study one brand of denture base acrylic resin was used to make specimens in the form of strips and maxillary denture bases. The specimens were cut and repaired with one type of an autopolymerizing adhesive resin and metal wires. The mechanical properties of the repaired specimens were measured, and the efficiency of each method was evaluated. The statistical results of this study revealed that geometric characteristics of a maxillary denture combined with the shape and pretreatment of reinforcement were the controlling factors for the overall mechanical behavior. Furthermore this study revealed that data with clinical significance can only be obtained by testing specimens similar to the original items used in dental practice.


Journal of Prosthetic Dentistry | 2009

Repeatability and interdevice reliability of two portable color selection devices in matching and measuring tooth color

Panagiotis Lagouvardos; Aggeliki G. Fougia; Sofia Diamantopoulou; Gregory L. Polyzois

STATEMENT OF PROBLEM There is a need to know how shade selection devices perform in matching and measuring tooth color, since these functions are usually evaluated independently and may present significant discrepancies. PURPOSE The purpose of this study was to evaluate 2 devices which offer both functions to test the null hypothesis that they present no differences in their repeatability and interdevice reliability relating to the 2 functions. MATERIAL AND METHODS Thirty-one extracted anterior human teeth were measured twice, with each of the devices (ShadeEye NCC and VITA EasyShade), by one investigator experienced and calibrated with both devices. L*a*b* values and shade matches to VITA Classical and Vitapan 3D-Master shade guide systems were determined for all teeth. Paired t tests and intraclass correlation coefficients (ICCs) were used to statistically analyze the data (alpha=.05). RESULTS The results showed that L*a*b* values with VITA EasyShade were significantly higher than those with ShadeEye NCC (P<.01), with a mean difference of 10.01 Delta E units. Device repeatability ICCs for measuring tooth color ranged from 0.693 to 0.929, with significant differences between devices only with respect to parameter L* (P=.042). Intradevice ICCs for matching tooth color ranged from 0.714 to 0.894, with significant differences between devices only with respect to the VITA Classical shade system (P=.042). Interdevice ICCs for measuring tooth color ranged from 0.402 to 0.486, with no significant differences between L*a*b* parameters, while interdevice matching reliability ranged from 0.189 to 0.430, with no significant differences between shade systems (P>.05). CONCLUSIONS All tooth color parameters were higher with the VITA EasyShade device. Measuring repeatability of the VITA EasyShade was higher than the ShadeEye NCC only for the L* parameter. Matching repeatability of the ShadeEye NCC was higher than the VITA EasyShade for the VITA Classical system. Interdevice measuring reliabilities were not different for the color parameters, but matching reliability of the VITA Classical system was higher than that of the Vitapan 3D-Master.


Gerodontology | 2012

Clinical evaluation of three denture cushion adhesives by complete denture wearers

Spyros Koronis; Evangelos Pizatos; Gregory L. Polyzois; Panagiotis Lagouvardos

OBJECTIVE The aim of this study was the clinical evaluation of three denture cushion adhesives and whether the results were correlated to Kapur Index for denture-supporting tissues. BACKGROUND Various types of denture adhesives are used among denture patients. However, information on the clinical behaviour of denture cushions is limited. MATERIALS AND METHODS Thirty edentulous patients had their denture-supporting tissues scored by Kapur Index and their old dentures replaced. They received three brands of denture cushion adhesives (Fittydent(®) , Protefix(®) and Seabond(®)) and were instructed to use them in a sequence according to the group they were randomly assigned to. Each brand of adhesive was used for 48 h on the lower denture according to the manufacturers suggestions. After each brand was used, participants spent 24 h without applying any sort of adhesive. Finally, a questionnaire evaluating and comparing the performance of each brand was filled out. RESULTS Denture adhesives generally improved patient satisfaction and masticatory ability, especially in participants with poor Kapur Index and those who reported a poor retention of their old dentures. CONCLUSION Fittydent(®) was the most preferred adhesive, showing the best retention and the longest duration of its effect, but also reported as difficult to remove from the denture-bearing area.


International Journal of Paediatric Dentistry | 2008

Clinical performance of a diode laser fluorescence device for the detection of occlusal caries in primary teeth

Katerina Kavvadia; Panagiotis Lagouvardos

OBJECTIVES To correlate the DIAGNOdent readings (LF) with those of direct visual (DV) examination, indirect visual (IDV) examination, bitewing radiography (BWR), and pit and fissure opening (PFO) for the detection of occlusal caries in primary teeth; to determine the validity of this device using PFO as reference; and to evaluate its reliability. METHODS Two calibrated operators examined 130 teeth with 405 examination sites using DV, IDV and radiographic examinations, and LF. Of the 405 sites, 155 were visually scored for caries after pit and fissure opening. RESULTS Pit and fissure opening was found to significantly correlate with all methods (rhoLF = 0.48, rhoBWX = 0.48, rhoDV = 0.44, rhoIDV = 0.41). For enamel lesions, higher sensitivity (0.76) was found with DV, while higher specificity (0.88) with the LF. For lesions into dentin, however, higher sensitivity (0.78) was found with the LF, while higher specificity (0.98) with the BWR. The devices accuracy was found to be 0.61 for enamel lesions, while for lesions into dentin 0.70, and its reliability was excellent (ICC = 0.97). CONCLUSION The LF device presented high reliability in the detection of occlusal caries in primary teeth and its performance was similar to DV and radiographic examinations.


Journal of Prosthetic Dentistry | 2014

Effect of adaptation time on the occlusal force at denture dislodgement with or without denture adhesive

Gregory L. Polyzois; Christos Partalis; Panagiotis Lagouvardos; Hector Polyzois

STATEMENT OF PROBLEM The effect of denture adhesives on the occlusal forces at the dislodgement (OFD) of new complete dentures during the adaptation period has not been previously studied. PURPOSE The purpose of this study was to investigate the OFD of dentures after their insertion and 3 months later, with or without denture adhesives. MATERIAL AND METHODS Thirteen volunteers with edentulism were enrolled in the study. Each participant had new complete maxillary and mandibular dentures. The occlusal forces (N) at denture dislodgement were assessed with or without 2 adhesives by using an electronic gnathodynamometer in the incisal and premolar regions on the existing denture, the new denture immediately after fitting, 45 days later, and 90 days later. The statistical analysis included the Wilcoxon and Kruskal-Wallis tests, repeated measures ANOVA, and the Pearson coefficient at α=.05. RESULTS Repeated measures ANOVA for new dentures showed that the OFD in the incisal or premolar region were significantly different between adaptation periods (P<.05) but not between adhesives. OFDs of dentures with and without adhesives correlated highly at all adaptation periods (0.912 to 0.995). CONCLUSIONS The adaptation period does affect the OFD of new dentures, but the 2 adhesives were found to have the same effect on the OFD.


European Archives of Paediatric Dentistry | 2009

Histological validation of a laser fluorescence device for occlusal caries detection in primary molars

D. Apostolopoulou; Panagiotis Lagouvardos; Katerina Kavvadia; L. Papagiannoulis

AIM: This was to validate in vitro a laser fluorescence device, DIAGNOdent™ 2095-DD, on the detection of occlusal caries in primary molars using the histological examination as the gold standard and to compare the laser fluorescence findings to the results of the conventionally used diagnostic methods. STUDY DESIGN AND METHODS: 111 occlusal pits in 24 extracted primary molars were examined for caries by one trained operator (Intra-examiner Reliability K>0.83), using direct visual (DV), indirect visual (IDV), radiographic (XR) and fluorescence (DD) examinations and then the extent of caries was determined histologically. Sensitivity, specificity, accuracy and the area under the ROC curve — AUC were calculated for all methods, using the histological evaluation as the gold standard. STATISTICS: Differences between examination methods were estimated by pair-wise comparison of their respective AUC. RESULTS: DD’s sensitivity for enamel and for dentine lesions respectively was 0.90 and 0.36, its specificity 0.36 and 0.91 and its accuracy 0.61 and 0.65. The DD device exhibited better sensitivity than specificity for enamel lesions and better specificity than sensitivity for lesions into dentine. The DD device was found to have the highest sensitivity for lesions into enamel, specificity and accuracy and as well as the largest AUC compared with all other methods. For lesions into dentine however, according to AUC values the DD was not statistically significant different from the other methods. CONCLUSION: Compared with the other methods, the DD had the highest validity for enamel caries while its validity for caries into dentine was not statistical different from the other methods.


Acta Odontologica Scandinavica | 2015

Effects of cleansing methods on 3-D surface roughness, gloss and color of a polyamide denture base material

Nick Polychronakis; Gregory L. Polyzois; Panagiotis Lagouvardos; Triantafillos Papadopoulos

Abstract Objective. The purpose of this study was to determine the effects of two denture cleansing methods on 3-D surface roughness, gloss and color of denture base materials. Materials and methods. Thirty disks from nylon (Valplast) and 30 from heat-polymerized acrylic denture base material (Paladon 65) were made and 10 of each material were immersed in water (control), Val-Clean (peroxide cleanser) and Corega Extradent (peroxide cleanser) plus microwaving for a period simulating 30 days of daily cleansing. 3-D surface roughness, gloss and color parameters were measured before and after cleansing using an interferometric profilometer, a gloss meter and a colorimeter. The results were statistically analysed by regression, paired-t, Mann-Whitney and Kruskal-Wallis tests at α = 0.05 level of significance. Results. The results showed significant differences at baseline in L* and b* parameters between materials (p < 0.01), with a significantly lower gloss (p < 0.05) and higher roughness (p < 0.05) for Valplast. After cleansing, Δε* was significantly greater in Valplast than Paladon 65 (p < 0.05). Gloss of both materials decreased significantly within the Corega Extradent plus microwave solution (p < 0.05), while roughness increased significantly only for Paladon 65 (p < 0.05). Conclusions. Valplast was found to have a significantly lower gloss and a higher roughness than Paladon 65 before cleansing. After cleansing, ΔE* increased more in Valplast than in Paladon 65, gloss of both materials decreased and roughness only of Paladon 65 increased within the Corega extradent plus microwaving method.


Lasers in Medical Science | 2012

Combined validity of DIAGNOdent™ and visual examination for in vitro detection of occlusal caries in primary molars

Katerina Kavvadia; Panagiotis Lagouvardos; Daphne Apostolopoulou

The purpose of this in vitro investigation was to compare in primary molars, the validity of DIAGNOdent™ 2095 on occlusal caries diagnosis used either separately or in combination with direct and/or indirect visual examinations, based on histological examination as the reference method. In 24 extracted primary molars, 111 occlusal pits were examined for caries by one trained operator (intra-examiner reliability k > 0.80), using the following examination methods: direct visual (DV), indirect visual (IDV), radiographic (XR), and fluorescence (DD) with the DIAGNOdent™. The extent of caries was then determined histologically. Sensitivity, specificity, accuracy, and the area under the ROC curve (AUC) were calculated for each method separately as well as for the combination of DD with DV and/or IDV. The DD accuracy was found both for lesions into enamel and into dentin to be 0.70 while the accuracy of the DD combination with DV and IDV was found to be 0.89. The DD AUC for lesions into enamel and into dentin, 0.68, were not statistically significant different from the other methods (p > 0.5), however the AUC of the combination of DD with DV and IDV, found to be 0.82, was higher than all the other methods, and this was statistically significant for enamel lesions. The validity of DIAGNOdent™ for occlusal caries diagnosis in primary molars was much higher when the DD was used in combination with direct and indirect visual examination, than when used by itself.


Gerodontology | 2012

Flexural and bond strengths of relined denture polymers assessed by four-point bending tests and Weibull analysis

Gregory L. Polyzois; Panagiotis Lagouvardos; Maria Frangou

OBJECTIVES The aim of this study was to (1) investigate the flexural strengths of three denture resins i.e. heat, photopolymerised and microwaved and how it was affected by relining with auto- and visible light-polymerised hard reliners, (2) investigate the bond strengths between denture resins and hard reliners and (3) interpret the results of both tests by utilising Weibull analysis. MATERIALS AND METHODS Specimens (65 × 10 × 2.5 mm) from denture resins, relined and bonded combinations were tested using a four-point bending test in a universal testing machine and a crosshead speed of 5 mm/min. Ten specimens for each bulk resin and denture resin-reliner combination for a total of 150 were tested. RESULTS Statistical analysis indicated significant differences between bulk materials (p < 0.001) and between reliners (p < 0.001) for flexural and bond strength tests. CONCLUSION was concluded that (1) the four-point flexural strength was different between the denture base materials, (2) flexure strength between bulk and relined or between relined with autopolymerised and photopolymerised bases was different, (3) flexural strength among relined denture bases was different and (4) bond strengths among relined denture bases were different.


Dental research journal | 2015

Volume fraction and location of voids and gaps in ultraconservative restorations by X-ray computed micro-tomography

Panagiotis Lagouvardos; Nick Nikolinakos; Constantine Oulis

Background: Volume fraction (Vf) and location of internal voids and gaps in relation to material type and cavity dimensions in ultraconservative restorations were investigated in this study. Materials and Methods: Forty-eight round cavities of 1.3 mm mean diameter and 2.6 mm mean depth were made on buccal and lingual surfaces of recently extracted human teeth. These were filled and thermocycled with two low viscosity composites (AeliteFlo LV [AF], PermaFlo [PF]), one high viscosity composite (Aelite aesthetic enamel [AA]) and one glass-ionomer (GCFuji IX GP). X-ray microtomography, following a specific procedure, was applied to all cavities before and after their restoration, using SkyScan-1072 microtomographer. Vf percent (Vf%) and location of voids and gaps were recorded and analysed statistically at a = 0.05. Kruskal-Wallis nonparametric analysis of variance, post-hoc analysis, Mann-Whitney test, Spearmans correlation analysis were used to analyze data. Results: Cavities filled with AF and PF showed significantly lower Vf % of voids and gaps than all other restorations (P < 0.05). Only for the cavities filled with AA, cavity width and depth was significantly correlated with Vf % (P < 0.05). 50-75% of the filled cavities contained internal voids regardless of the restorative material (P > 0.05). The proportion of cavities with gaps at the bottom and side walls was lower in those filled with AF and PF (P < 0.05). Conclusion: Cavities filled with low viscosity composites presented the lowest amount of internal voids and gaps. Glass-ionomer and high viscosity composite restorative materials showed the highest amount of interfacial gaps. Only in the high viscosity composite restorations the amount of voids and gaps correlated with the cavity depth, width and volume.

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Gregory L. Polyzois

National and Kapodistrian University of Athens

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Katerina Kavvadia

National and Kapodistrian University of Athens

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A. G. Andreopoulos

National Technical University of Athens

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Christos Partalis

National and Kapodistrian University of Athens

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Constantine Oulis

National and Kapodistrian University of Athens

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Nick Polychronakis

National and Kapodistrian University of Athens

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Panagiotis Zoidis

National and Kapodistrian University of Athens

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Triantafillos Papadopoulos

National and Kapodistrian University of Athens

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Aggeliki G. Fougia

National and Kapodistrian University of Athens

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