Influence of Dental Restorations on Oxidative Stress in Gingival Crevicular Fluid.

Biocompatibility of dental materials (DM) can be evaluated by gingival crevicular fluid (GCF) oxidative stress (OS) status. The goal of the study was to ascertain influence of dental caries degree, teeth position, and type and amount of applied DM on GCF OS profile. For this purpose, we tested six DMs that were sealed in one session: amalgam (Amg), composites: Tetric EvoCeram and Beautifil (BF), phosphate cement-zinc phosphate and polycarboxylate cements-zinc polycarboxylate cements, and glass ionomer cement (GIC). The study included 88 dental outpatients. Follow-up was scheduled at 7th and 30th day. Oxidative stress parameters (malondialdehyde (MDA) and glutathione (GSH) levels and total superoxide dismutase (tSOD) activity) were measured before (0th day) and after the treatment (7th and 30th day) in GCF. Control teeth were mirror-positioned healthy teeth. The DM accomplished the following effects (listed in descending order): increase of GSH in GCF was realized by ZPoC > BF > GIC > Amg; tSOD activity increase by ZPoC > BF > Amg; and MDA decrease by ZPoC > ZPhC > Amg > TEC. Dental caries provokes insignificant rise of OS in GCF. ZPoC and ZPhC showed the highest antioxidant effect, contrary to GIC. Restorations with antioxidant properties may reduce gum diseases initiated by caries lesion, what is of great clinical relevance in dentistry.

Prosthetic treatment after teeth extractions in patients with type 2 diabetes mellitus.

Introduction: Good and well balanced diet provided by adequate mastication is part of therapy in patients with type 2 diabetes mellitus (DM). The critical period presents the time immediately after teeth extractions; hence, immediate denture is a rational therapeutical choice for diabetic patients. The presence of immediate denture and its compression might compromise wound healing process, affect chewing ability, food intake and consequently blood glucose level in type 2 DM patients. Objective: The objective of this study was to compare socket opening diameters (SOD), chewing ability, changes in blood glucose level and food intake in type 2 DM patients with and without maxillary immediate complete denture (MICD) during a three-week wound healing period. Methods: The study comprised 78 type 2 DM partially removable denture wearers (42 candidates for teeth extractions and 36 candidates for teeth extractions and insertion of MICDs). During the three-week period participants were followed for SOD, chewing ability and changes in blood glucose level and food intake. Results: Patients with MICD showed significantly lower reduction of SOD (seventh, 14th, 21st day) and higher chewing ability (seventh, 14th, 21st day) in comparison to patients without an MICD. Significantly lower number of patients with an MICD had changes in blood glucose level and food intake. Conclusion: Maxillary immediate complete denture presents a good therapeutic choice for type 2 DM patients, as it provides possibility of adequate mastication after teeth extractions and maintenance of nutritional status and blood glucose level.

Introduction to verification of the GOHAI instrument for measuring the oral health-related quality of life in patients with dentures using the Serbian preliminary version--A pilot study.

BACKGROUND/AIM: Quality of life related to health should be seen as a multidimensional concept that, in addition to the physical symptoms associated with a disease and treatment, should include physical, psychological and social functioning of a person. The primary objective of this study was to use the Serbian preliminary version of the Geriatric Oral Health Assessment Index (GOHAI) questionnaire in oder to examine the consistency, reliability and stability, as well as an introduction to the verification tool. METHODS: The GOHAI questionnaire with 6-level Likert scale, translated into Serbian, including the relevant oral health characteristics (oral hygiene, required dentures, number of teeth extracted), was filled by five specialists in prosthodontics for 30 randomly selected respondents, before and after the dental prosthetic treatment. Subsequently, in order to measure the reliability of the questionnaire, 27 patients were re-interviewed. RESULTS: The value of Cronbach's Alpha Coefficient (Crα) before the treatment was 0.878, and after the treatment it was 0.788 confirming the internal consistency and stability of the questionnaire. The validity of discriminatory properties of the GOHAI was confirmed by the Spearman's correlation coefficient (r), which was highly significantly associated with oral health characteristics, confirming the high reliability of the measurement. The results of test-retest analysis measured by the individual Pearson's correlation coefficient (r) were in the range of 0.34-0.97, and for the total score r was 0.927, while the Kappa coefficient was 0.63. The correlation analysis of the GOHAI score before the treatment showed that for 10 questions there was a statistically significant correlation of the score with the answers to the questions, and for 6 questions Spearman's r was ≥ 0.7. After the treatment a highly significant correlation of the GOHAI was shown with the answers to 10 questions, while for 5 questions the Spearman's r was > 0.6. The GOHAI average score before the treatment was 19.44 ± 11.12, and after the treatment 2.77 ± 3.83, where the lower value indicates better quality of life. CONCLUSION: The results of this pilot study confirm internal consistency and stability of the Serbian preliminary version of the GOHAI questionnaire and the causal relation between the quality of life and the characteristics of oral health of the patients with dentures. Accordingly, instrument verification is recommended.

Evaluation of conventional and digital radiography capacities for distinguishing dental materials on radiograms depending on the present radiopacifying agent.

BACKGROUND/AIM: The radiopacity of an endodontic material can considerably vary as measured on film and a digital sensor. Digital radiography offers numerous advantages over conventional film-based radiography in dental clinical practice regarding both diagnostic capabilities and postintervention procedures. The aim of this study was to investigate the capacity of conventional and charge-conpled device (CCD) based digital radiography to detect material on radiograph depending on the radio-pacifying agent present in the mate- rial. METHODS: Experimental cements were formulated by mixing Portland cement with the following radiopacifying agents: zinc oxide (ZnO), zirconium oxide (ZrO2), titanium dioxide (TiO2), barium sulphate (BaSO4), iodoform (CHI3), bismuth oxide (Bi2O3) and ytterbium trifluoride (YbF3). In addition, 5 endodontic materials comprising Endometh- asone, Diaket, N2, Roth 801 and Acroseal were investigated to serve as control. Per three specimens of each material were radiographed alongside an aluminum step wedge on film (Eastman Kodak Company, Rochester, NY) and a CCD-based digital sensor (Trophy Radiologie, Cedex, France). Radiopacity values were calculated by converting the radiographic densities of the specimens expressed as a mean optical densities or mean grey scale values into equivalent thickness of aluminum. RESULTS: Two-way ANOVA detected no significant differences with respect to the imaging system (p > 0.05), but the differences were significant with respect to radiopacifier (p < 0.001) and the interaction of the two factors (p < 0.05). Paired t-test revealed significant differences between the methods used for pure Portland cement, all concentrations of BaSO4 and CHI3, 10% and 20% additions of ZrO2 and Bi2O3 and 10% and 30% additions of YbF3 (p < 0.05). CONCLUSION: The materials which incorporate CHI3 OR BaSO4 as radiopacifying agents are expected to be significantly more radiopaque on a digital sensor than on film. During clinical practice one should concern to the quality of contrast assessment obtained by digital according to conventional radiography.

The effect of disinfectants on dimensional stability of addition and condensation silicone impressions.

BACKGROUND/AIM: Dimensional stability and accuracy of an impression after chemical disinfection by immersion in disinfectants are crucial for the accuracy of final prosthetic restorations. The aim of this study was to assess the deformation of addition and condensation silicone impressions after disinfection in antimicrobial solutions. METHODS: A total of 120 impressions were made on the model of the upper arch representing three full metal-ceramic crown preparations. Four impression materials were used: two condensation silicones (Oranwash L - Zhermack and Xantopren L Blue - Heraeus Kulzer) and two addition silicones (Elite H-D + regular body - Zhermack and Flexitime correct flow - Heraeus Kulzer). After removal from the model the impressions were immediatel immersed in appropriate disinfectant (glutaraldehyde, benzalkonium chloride - Sterigum and 5.25% NaOC1) for a period of 10 min. The control group consisted of samples that were not treated with disinfectant solution. Consecutive measurements of identical impressions were realized with a Canon G9 (12 megapixels, 2 fps, 6x/24x), and automated with a computer Asus Lamborghini VX-2R Intel C2D 2.4 GHz, by using Remote Capture software package, so that time-depending series of images of the same impression were obtained. RESULTS: The dimensional changes of all the samples were significant both as a function of time and the applied disinfectant. The results show significant differences of the obtained dimensional changes between the group of condensation silicones and the group of addition silicones for the same time, and the same applied disinfectant (p = 0.026, F = 3.95). CONCLUSION: The greatest dimensional changes of addition and condensation silicone impressions appear in the first hour after their separation from the model.

Eugenol-based temporary luting cement possesses antioxidative properties.

INTRODUCTION: Antioxidants protect against reactive oxygen species and expose beneficial anti-inflammatory activity when in contact with biological tissues. Dental materials that are used as temporary luting on fixed dental restorations are often in contact with injured gingival tissue, hence they should contain anti-inflammatory characteristics that are essential after prosthetic procedures preceding cementation of final restauration. OBJECTIVE: The aim of this study was to investigate the antioxidant effect through the oxidation inhibition (OI) of mixed dental cement for temporary luting or their liquid component. METHODS: Eight study groups were prepared each by ten samples: 1) ex tempore preparation of zinc-oxide eugenol paste (Kariofil Z Galenika, Serbia), 2) Viko Temp paste (Galenika, Serbia), 3) Temp Bond NE paste (Kerr, Germany), 4) ScutaBond (ESPE, Germany), 5) Cp-CAP paste (Germany, Lege Artis) and oil component of 6) Kariofil Z, 7) Viko Temp and 8) Cp-CAP. The samples were subjected to spectrophotometer to measure OI 2,2'-azino-di-(3-ethyl-benzthiazoline-6-sulphonic acid) (ABTS) using Randox kit, United Kingdom. The control samples were pure ascorbic acid (1% w/v). RESULTS: High values of OI exposed materials (groups 1, 5, 6, 7, 8) with content of eugenol (or its derivates) in the range of 100-88.8% were statistically more significant than the values of non-eugenol substances (groups 2, 3, 4) with the range of 8.2-43.5%. CONCLUSION: Eugenol containing temporary fixation materials show significant antioxidative properties and therefore they may be used in those clinical situations where surrounding gingival tissue is injured during restorative procedure.

In vitro radiographic detection of cement overhangs on cement-retained implant restorations.

PURPOSE: The aim of this in vitro study was to investigate the potential of digital and conventional radiography to detect small amounts of residual dental luting cements around implant abutments. MATERIALS AND METHODS: Artificial cement and aluminum overhangs in varying thicknesses, heights, and depths were radiographed adjacent to implant restorations with a radiovisiography sensor. Five trained evaluators were asked to identify the smallest depth of overhang that could be detected on radiographs. RESULTS: For detection of cement overhangs adjacent to implant abutments, a luting agent must have greater radiopacity than what is recommended by relevant International Organization for Standardization directives. To detect a 0.1-mm-thick portion of excess cement adjacent to an implant abutment, the cement should have a radiopacity of at least 1.7 mm of aluminum for high-resolution digital radiographs and 2.2 mm of aluminum for film-based radiographs. Two-way analysis of variance revealed that the thickness of the specimens, type of imaging detector, and type of cement all affected the radiopacity threshold for artificial cement excess (P < .05). The height of the specimens and the surrounding structures were not statistically significant factors in cement detection. CONCLUSIONS: Digital radiography offers better possibilities for visualization of cement excess than conventional radiography.

An in vitro radiographic analysis of the density of dental luting cements as measured by CCD-based digital radiography.

OBJECTIVE: According to the ISO, the radiopacity of luting cements should be equal to or greater than that of aluminum. The aim of this in vitro study was to determine the radiopacity of 13 commercially available dental luting cements and compare them with human enamel and dentin. METHOD AND MATERIALS: Five classes of luting cements were evaluated: zinc phosphate (Cegal N and Harvard Zinc Phosphate), zinc polycarboxylate (Harvard Polycarboxylate and Hoffmann's Carboxylate), glass ionomers (Ketac Cem Easymix, Ketac Cem Radiopaque, and Fuji I), resin-modified glass ionomer (Rely X Luting), and resin cements (Multilink Automix, Variolink II, Speed CEM, Rely X Unicem Automix, and three shades of Variolink Veneer). Tooth slices served as controls. Five specimens of each material measuring 8 mm in diameter and 1 mm thick were prepared and radiographed alongside tooth slices and an aluminum stepwedge using a Trophy RVG sensor. The radiopacity values were expressed in mm Al and analyzed by the ANOVA and Tukey tests (P < .05). RESULTS: All the cements examined except Variolink Veneer had significantly higher radiopacities than that of dentin. Rely X Unicem Automix, glass ionomer, and resin-modified glass-ionomer cements demonstrated radiopacities that were not significantly different with respect to enamel. Zinc phosphate, zinc polycarboxylate, and three of the resin cements presented radiopacity values that were significantly greater than that of enamel. CONCLUSION: Almost all the investigated materials presented an acceptable radiopacity. Radiopacity of dental cements seems to depend more on the presence of elements with high atomic numbers than on the type of the material.

In vitro evaluation of microleakage of various types of dental cements.

INTRODUCTION: Microleakage is defined as the clinically undetectable seepage of oral fluids containing bacteria and debris between cement layer and tooth restoration. OBJECTIVE: This in vitro study investigated the effect of different dental cements (zinc-phosphate, polycarboxylate, glass-ionomer and resin cement) on microleakage in different ceramic crown systems (metal ceramic crown, metal ceramic crown with a porcelain margin, Empress 2 and in Ceram all-ceramic crowns) fixed on extracted human teeth. METHODS: One hundred and sixty intact human premolars were randomized to four groups of forty teeth each, according to the different ceramic crown systems. They were prepared in a standardized manner for metal-ceramic and all-ceramic crowns. Crowns were made following a standard laboratory technique, and each group of crowns were divided into four groups according to the different cement agents and cemented on their respective abutments. The specimens were subjected to thermocycling, placed in methylene blue solutions, embedded in resin blocks and vertically cut in the bucco-oral and meso-distal direction. The microleakage in the area of tooth-cement interface was defined as linear penetration of methylene blue and was determined with a microscope to assign microleakage scores using a five-point scale. RESULTS: A significant association was found between a cement type and degree of microleakage (p = 0.001). No statistically significant differences were found among the different ceramic crown systems luted with the same dental cement. The smallest degree of microleakage was observed in specimens luted with resin cement (X = 1.73), followed by glass-ionomer cement (X=2.45) and polycarboxylate cement (X = 3.20). The greatest degree of microleakage was detected in the crowns fixed with zincphosphate cement (X = 3.33). CONCLUSION: The investigated dental cements revealed different sealing abilities. The use of resin cement resulted in the percentage of 0 microleakage scores. Due to this feature, the resin cement is to be recommended in everyday clinical practice.

The role of occlusal factor in the etiology of temporomandibular dysfunction.

INTRODUCTION: The influence of occlusal condition at the onset of temporomandibular disorders (TMD) has been strongly debated for many years and still is the source of controversy. Up to the eighties in the last century, the occlusal factors such as the presence of uncured malocclusions, discrepancies between intercuspal position and retruded contact position greater than two millimeters, retrusive and nonworking side interferences and loss of posterior teeth were considered to be the primary causes of TMD. OBJECTIVE: The aim of this study was to estimate the role of occlusal factor in the etiology of craniomandibular dysfunction and therapeutic effects of irreversible occlusal therapy (occlusal equilibration) in patients with TMD. METHODS: In the investigation we studied a group of 200 men and women. The average age of the selected patients was between 18 and 25 years. The purpose of TMD signs and symptoms was confirmed in every patient using a special functional analysis and evaluating the craniomandibular index (CMI) according to Fricton and Schiffman. The value of craniomandibular index was determined in the group of 15 patients with signs and symptoms of temporomandibular dysfunction. In the study groups occlusal equilibration (selective grinding) was performed according to Okeson using the central position of the mandible as the referent position in the occlusal therapy. The value of CMI was determined before and 30 days after occlusal equilibration. RESULTS: The results of this study confirmed the significant reduction in the signs and symptoms of TMD after occlusal equilibration. The statistical elaboration of the differences between the values of CMI I (before treatment) and CMI II (30 days after treatment) revealed highly significant differences. The CMI I values in the group ranged between 0.076 and 0.346 with the mean value of 0.188 +/- 0.082.The values of CMI II ranged between 0.038 and 0.19 with the mean value of 0.038 +/- 0.053. CONCLUSION: The study conformed the validity of irreversible occlusal therapy (selective grinding) in patients with TMD.

[Factors influencing bonding fixed restorations].

INTRODUCTION: Crown displacement often occurs because the features of tooth preparations do not counteract the forces directed against restorations. OBJECTIVE: The purpose of this study was to evaluate the effect of preparation designs on retention and resistance of fixed restorations. METHOD: The study was performed on 64 differently sized stainless steel dies. Also, caps which were used for evaluated retention were made of stainless steel for each die. After cementing the caps on experimental dies, measuring of necessary tensile forces to separate cemented caps from dies was done. Caps, which were made of a silver-palladium alloy with a slope of 600 to the longitudinal axis formed on the occlusal surface, were used for evaluating resistance. A sudden drop in load pressure recorded by the test machine indicated failure for that cap. RESULTS: A significant difference was found between the tensile force required to remove the caps from the dies with different length (p < 0.05) and different taper (p < 0.01). The greatest retentive strengths (2579.2 N and 2989.8 N) were noticed in experimental dies with the greatest length and smallest taper. No statistically significant (p > 0.05) differences were found between tensile loads for caps cemented on dies with different diameter. Although there was an apparent slight increase in resistance values for caps on dies with smaller tapers, the increase in resistance for those preparation designs was not statistically significant. There was a significant difference among the resistance values for caps on dies with different length (p < 0.01) and diameter (p < 0.05). CONCLUSION: In the light of the results obtained, it could be reasonably concluded that retention and resistance of the restoration is in inverse proportion to convergence angle of the prepared teeth. But, at a constant convergence angle, retention and resistance increase with rising length and diameter.

[Gingival and dental parameters in evaluation of esthetic characteristics of fixed restoratons].

This paper argues on importance of gingival and dental parameters in evaluation of esthetic characteristics of fixed restorations. Human beauty is a specific category which is not easy to define by means of any known criteria or with mathematic formula. But, it is also important for practitioners to take into consideration some objective rules determining what is really nice and appealing. In reconstructing the personal identity, it is essential to harmonize the esthetic features. In dental practice, this approach means to establish a close correlation among the facial, dental, gingival and physical components of orofacial system. For the purpose of this study, the authors have divided the overview of esthetic principles into two parts. The first one deals with some objective parameters such as: gingival health, the zenith of gingival contour, the balance of gingival levels, relative tooth dimensions, the golden proportion of the teeth, the design of dental arch, interdental contact areas, interdental closure, the contour of incisal edge and the shape of interincisal angles. The esthetic integration of these parameters into a frame of smile and the whole face, as well as some subjective criteria are discussed in the second part of the paper.

[Concept of "long centric"]. / Koncept "long centric".

The objective of this paper was to show the historical perspective of the "long centric" occlusal concept and its importance in the modern dentistry, especially from the gnathological aspect. The "long centric" concept represents therapeutic modality used in modern dentistry and occlusal adjustment in all patients showing differences in strong and weak closure of the lower jaw starting from the position of physiological rest. "Long centric" concept is applied only for anterior teeth and occlusal movements from rather than toward the center. Whenever the "long centric" parameters are not adequate, occlusal disturbance, resulting from the "wedge" effect during the initial closure of the lower jaw, is present. Different degrees of abrasion or hypermobility of the teeth are often the result of the above-mentioned occlusal disturbances and can potentially trigger bruxism and malfunction. Modus procedendi should be the regular approach of every dentist to any occlusion, because only the built-in "long centric" efficiently contributes to the occlusal stability of the anterior portion of the dentition. All occlusions should be routinely tested regarding their need for "long centric", especially when the extensive therapeutic interventions (conservative, prosthetics) of the occlusal complex are required.