Emissions of total volatile organic compounds and indoor environment assessment in dental clinics in Athens, Greece.

OBJECTIVE: To quantify the amount of Total Volatile Organic Compounds (TVOCs) emitted from five dental substances commonly used in a dental clinic. METHOD: An assessment of the indoor air quality in two clinics of the Athens University Dentistry Faculty was conducted. RESULTS: It was found that TVOC emissions from Kalocryl and Bacillol reached extremely high values affecting the air in the dental clinics at short and long distances from the source. Six pollutants TVOCs, CO2, PM10, PM2.5, SO2 and NO(x) were measured and indoor sources associated with dental activities were identified. Very high concentrations of TVOCs were found which exceeded the acceptable levels by a factor of 20, associated with the nature of the dental activities and the ventilation conditions. The CO2 concentration levels were high and the indoor conditions were considered unsatisfactory, associated with the number of occupants and the ventilation conditions. PM concentrations were high due to the nature of the dental activities and they exceeded the outdoor levels by a factor of 5 to 6. The concentrations of the gaseous pollutants NO(x) were low while the SO2 concentrations were hardly detectable.

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.

Indoor air quality in a dentistry clinic.

The purpose of this work is to assess, both experimentally and theoretically the status of air quality in a dentistry clinic of the Athens University Dentistry Faculty with respect to chemical pollutants and identify the indoor sources associated with dental activities. Total VOCs, CO(2), PM(10), PM(2.5), NO(x) and SO(2) were measured over a period of approximately three months in a selected dentistry clinic. High pollution levels during the operation hours regarding CO(2), total VOCs and Particulate Matter were found, while in the non-working periods lower levels were recorded. On the contrary, NO(x) and SO(2) remained at low levels for the whole experimental period. These conditions were associated with the number of occupants, the nature of the dental clinical procedures, the materials used and the ventilation schemes, which lead to high concentrations, far above the limits that are set by international organizations and concern human exposure. The indoor environmental conditions were investigated using the Computational Fluid Dynamics (CFD) model PHOENICS for inert gases simulation. The results revealed diagonal temperature stratification and low air velocities leading to pollution stratification, accompanied by accumulation of inert gaseous species in certain areas of the room. Different schemes of natural ventilation were also applied in order to examine their effect on the indoor comfort conditions for the occupants, in terms of air renewal and double cross ventilation was found to be most effective. The relative contribution of the indoor sources, which are mainly associated with indoor activities, was assessed by application of the Multi Chamber Indoor Air Quality Model (MIAQ) to the experimental data. It was found that deposition onto indoor surfaces is an important removal mechanism while a great amount of particulate matter emitted in the Clinic burdened severely the indoor air quality. The natural ventilation of the room seemed to reduce the levels of the fine particles. The emission rates for the fine and coarse particulates were found to be almost equal, while the coarse particles were found susceptible to deposition onto indoor surfaces.

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.

Effect of topical fluoride agents on the morphologic characteristics and composition of resin composite restorative materials.

STATEMENT OF PROBLEM: The high reactivity of fluoride agents used in topical fluoride treatments have raised important questions on their potential adverse effects on restorative materials. PURPOSE: The purpose of this study was to evaluate the effect of topical fluoride agents used for office or home treatments on the surface morphologic characteristics and composition of composite restoratives. MATERIAL AND METHODS: The fluorides used were Act, Phosflur, Gel II, Prevident, Stop, Butler APE, Nupro, and Omni Gel & Rinse. The composites tested were Brilliant DI, Heliomolar Ro, Herculite XRV, and P-50. The pH of the fluorides was measured as received and after dilution with water at a 1:3 volume ratio. The composites were subjected to the fluoride treatments until the total number of applications simulated the equivalent of 4 years under treatment. The changes induced on the surface morphologic features and composition of the restoratives were assessed by multiple internal reflectance Fourier transform infrared spectroscopy, scanning electron microscopy, and x-ray microanalysis. RESULTS: All fluorides showed an acidic pH that was not significantly changed after dilution, except Stop, which exhibited a significant pH reduction. All fluorides increased the amount of loosely bound water in the composite matrix. Butler APF gel was the most aggressive for Brilliant DI and Herculite XRV, leading to excessive surface degradation, porosity, destruction of the filler-matrix interface, filler dissolution, and debonding. A reduction in the extent of remaining C = C bonds was observed in Herculite XRV after Butler APF treatment; Phosflur, Gel II, and Prevident had a milder effect. Treatment of Brilliant Dl and Herculite XRV with Omni Gel & Rinse resulted in the formation of a stable precipitation layer rich in barium, phosphorus, tin, oxygen, and fluoride. P-50 was severely affected at the resin-matrix interface after Stop treatment, whereas Omni Gel & Rinse induced fewer surface changes. Heliomolar Ro was the least affected restorative regardless of the type of fluoride used.

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.

[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.

[In vitro study of the microleakage pattern around posterior composite resin restorations using a new dentin bonding agent]. / Ergasteriake melete tes oriakes mikrodieisdyses se apokatastaseis synthetes retines me ten parembole enos neou sygkolletikou paragonta.

A totally new product, by the name Scotchbond 2 (3M Co) appeared recently in the field of bonding agents. Grace to its improved formula, the manufacturers claim that both the bond strength and the sealing ability of the material, render it trustful for use in both anterior and posterior composite resin restorations. The purpose of this in vitro investigation was to determine the microleakage pattern around slot type cavities, restored with posterior composite resin (P-50, 3M Co) using two different generations of bonding agents. Two types of cavities were prepared in sound premolars extracted for orthodontic reasons. In the first group (10 teeth) the cervical wall was located in the enamel, above the cementoenamel junction and in the second group (10 teeth) the cervical wall was located below the CEJ. The enamel surrounding the cavity margins was etched using 37% orthophosphoric acid gel, rinsed and dried and the bonding agents were applied and cured according to the manufacturer s instructions. The posterior composite was condensed and light-cured incrementally, in three horizontal layers. The samples were thermocycled for 200 cycles of 4 minutes each between 4.37 and 60 degrees centigrade, covered with fingernail varnish and sticky wax and immersed in 0.5% basic fuchsin dye for 12 hours. The specimens were split in two halves longitudinally in a mesiodistal direction in a hard tissues microtome and the degree of dye penetration was evaluated using an optical microscope. According to the results obtained we come to the conclusions that: 1. The use of Scotchbond 2 minimized but did not eliminate the microleakage around posterior composite resin restorations, in both types of cavities.(ABSTRACT TRUNCATED AT 250 WORDS)

[Effect of bonding agents in the degree of microleakage around posterior composite resin restorations]. / E epidrase ton sygkrolletikon paragonton sto bathmo tes oriakes mikrodieisdyses se apokatastaseis me synthetes retines opisthion.

The purpose of this in vitro study was to examine, by the dye technique, the microleakage pattern of two posterior composite resin materials, alone or combined with three commercially available dentin bonding agents. Composite resins used were P-30 (3M) and Heliomolar (Vivadent). The bonding agents were Gluma (Bayer), Scotch-bond LC (3M) and Dentin Adhesit (Vivadent). MOD cavities were prepared on extracted posterior teeth with a 330 tungsten carbide bur, in an airtor handpiece. The gingival floor of the mesial surface was located in the enamel above the CEJ and the distal gingival floor in the cementum below the CEJ. Specimens were thermocycled between 4 degrees and 60 degrees C for fifty cycles of two minutes each and imbibed for 10 hours in a 2% basic fuchsin solution and split in two halves. According to the results we obtained we came to the conclusion that: Both composite resins exhibited significant microleakage when they were used alone, without bonding agent. The gingival floor of the mesial surface (located in the enamel) exhibited in most specimens, less microleakage than the distal one. The use of bonding agents decreased but not eliminated the microleakage at the gingival floor of the cavities.