Prospective, 1-year observational study of double-threaded tapered body dental implants with immediate loading.

STATEMENT OF PROBLEM: Unlike conventional loading protocols, the immediate loading of single implants has not been fully investigated. PURPOSE: The purpose of this study was to assess the prosthetic and esthetic periimplant mucosal outcomes of immediately restored dental implants during a 1-year follow-up. MATERIAL AND METHODS: Twenty participants meeting the established inclusion criteria received double-threaded, tapered body dental implants (SuperLine; Dentium). Implants were placed and stabilized at a minimum of 35 Ncm of torque and restored immediately after the surgery with interim restorations. These were replaced with definitive restorations 6 months after implant placement. Clinical measurements at each visit included resonance frequency analysis, the evaluation of the participants' oral health (gingival and plaque indices), and the esthetic outcome of the interim or definitive restoration. RESULTS: Implants placed in this clinical study had a 100% success rate. The oral health and esthetic outcomes were favorable for all participants. CONCLUSIONS: Double-threaded, tapered body dental implants that were placed and immediately restored with fixed interim prostheses and with definitive prostheses after 6 months remained stable and functional after 1 year.

Effect of gypsum separating media on the appearance of stone cast surfaces.

STATEMENT OF PROBLEM: Several well-known parameters influence the appearance of the denture base surface, including proper isolation of the dental stone. There is lack of data describing the influence of this parameter on the appearance of the denture base surface. PURPOSE: The purpose of this study was to evaluate the effectiveness of 2 dental stone separating media on the surface of the denture base. MATERIAL AND METHODS: A conventional flasking technique for fabricating a denture base was used. Twenty casts were poured with Type III yellow dental stone to produce 20 identical denture bases. Each cast was sectioned into halves. One half of the cast was treated with Al-Cote (control group) and the other half with Iso-K separating material. Once the denture base was finished, a single examiner, blinded to the experiment, visually compared the 2 surfaces of each cast (right and left part of the cast) under natural light to determine which surface was glossier. The McNemar test (.05 significance level) was used to compare the discordant pairs (20 discordant pairs). RESULTS: Two pairs (10%) were glossier than the Iso-K treatment, and 18 pairs (90%) within the Iso-K treatment were glossier than the treatment with Al-Cote. A statistically significant difference was found between the 2 treatments (P<.001). The odds ratio was 9.00, with a 95% confidence interval of 2.155 to 79.981. CONCLUSIONS: When used according to the manufacturer's instructions, denture surfaces treated with Iso-K appeared glossier than when treated with Al-Cote separating material.

Detection of Leachable Components from Conventional and Dental Bulk-Fill Resin Composites (High and Low Viscosity) Using Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) Method.

The aim of this study was to investigate leachable components (monomers) in high and low viscosity dental bulk-fill resin composites and conventional resin composite materials after polymerization. Six bulk-fill and six conventional dental resin composite materials were used in this study. The samples of each material (three sets of triplicates) were cured for 20 s with irradiance of 1200 mW/cm2 with a LED curing unit and immersed in a 75% ethanol solution at 37 °C. The eluates from each triplicate set were analyzed after 24 h, 7 days or 28 days using liquid chromatography coupled with triple quadrupole tandem mass spectrometry (LC-MS/MS). Detectable amounts of 2-Hydroxyethyl methacrylate (HEMA) were found in both Gradia materials and the amount observed across different time points was statistically different (p ˂ 0.05), with the amount in solution increasing for Gradia and decreasing for Gradia Direct flo. Bisphenol A diglycidildimethacrylate (BIS GMA) was found in Filtek and Tetric materials. Triethylene glycol dimethacrylate (TEGDMA) was detected in all materials. On the other hand, there were no statistically significant differences in the amounts of TEGDMA detected across different time points in either of the tested materials. Monomers HEMA, TEGDMA, 4-dimethylaminobenzoic acid ethyl ester (DMA BEE) and BIS GMA in bulk-fill and conventional composites (high and low viscosity) can be eluted after polymerization. The good selection of composite material and proper handling, the following of the manufacturer's instructions for polymerization and the use of finishing and polishing procedures may reduce the elution of the unpolymerized monomers> responsible for the possible allergic and genotoxic potential of dental resin composites.

Restoration using gingiva-colored ceramic and a ridge lap pontic with circumferential pressure: a clinical report.

Achieving an optimal esthetic result when replacing missing teeth with implant-supported restorations in the esthetic zone is a demanding surgical and restorative challenge. This clinical report describes the use of a cantilevered, cemented, implant-supported restoration with gingiva-colored ceramics and a circumferential pressure-ridge lap pontic to replace 2 incisors and the adjacent tissue.

In vitro assessment of human dentin wear resulting from toothbrushing.

It is well-recognized that toothbrushing is the most widely used method for daily oral hygiene maintenance. This in vitro study examines dentin surface wear resulting from the use of an oral hygiene device in a controlled oral condition. Powered toothbrushes produce less wear than manual brushes. However, depending on their design and applied forces, they can also produce varying levels of dentin wear.

Influence of curing mode intensities on cell culture cytotoxicity/genotoxicity.

PURPOSE: This study determined the cytotoxic/genotoxic effect of different curing modes on cell culture. METHODS: A thin layer of lymphocyte cultures was cured applying three different curing modes of Bluephase C8 LED curing unit. Cultures were exposed to light directly or through a layer (2 mm) of polymerized resin composite sample. Cells were analyzed using trypan blue exclusion test, acridine orange/ethidium bromide dyeing technique, and alkaline comet assay. RESULTS: Only low intensity mode after direct exposure significantly increased the number of nonviable lymphocytes detected using trypan blue. All curing procedures significantly increased the number of apoptotic lymphocytes regardless whether the exposure occurred directly or through the composite. Low intensity mode in direct exposure significantly elevated DNA migration compared to other curing modes. 1 hour after exposure significant increase in tail length and intensity for all modes and procedures was detected. However, DNA damage measured for cultures cured by low intensity mode was higher compared to the other two modes; thus, despite of curing light intensity, longer curing time leads to greater cytotoxicity/genotoxicity in cell culture.

Simulated tissue using a unique pontic design: a clinical report.

Unfavorable relationships between the residual edentulous ridge, pontic, and gingival papilla may compromise the definitive result of a restoration. Different procedures have been described and developed to improve the relationship between esthetics and functionally acceptable fixed partial dentures. This article describes a unique pontic design as well as the application of pressure during insertion of the pontic to achieve proper tissue displacement. Controlled pressure enhances the interdental papilla and creates the illusion of pontics emerging from the soft tissue, providing the restoration with a natural-looking effect.

Effects of Light Attenuation through Dental Tissues on Cure Depth of Composite Resins.

OBJECTIVE: Polymerization of light-cured resin-based materials is well documented; however, the intensity of the activating light can be reduced by passage through air, dental structure, or restoration compromising the physical properties of the restoration. The aim of this study was to evaluate the depth of cure of different light cured composite resins polymerized directly or transdental, through enamel and enamel/dentin tissues. MATERIAL AND METHODS: Five composite resins were selected for this experiment: SureFil SDR, Dentsply (SDR), Filtek Supreme Plus, 3M ESPE (FSP), Aelite LS, Bisco (ALS), Filtek LS, 3M ESPE (FLS), and TPH, Dentsply (TPH). Thirty specimens of each material were prepared with 2- or 4-mm thickness. The specimens were light-cured (Elipar 2500, 3M ESPE) for 40 sec using three different protocols: direct or transdental, through a disc of enamel with 1 mm of thickness, and a disc of enamel and dentin with 2 mm of thickness. Eight Vickers microhardness (VH) measurements were taken from each specimen, four on top and four on bottom surface (Micromet, Buehler, 100 g per 15 sec). Data was analyzed with ANOVA three-way, Tukey HSD post-hoc (α = .05). RESULTS: Bottom surfaces of specimens exhibited statistically significant lower Vickers microhardness than the top surfaces for all composite resin evaluated, regardless of the curing conditions, except for the SDR when direct light-cured. Transdental light curing through enamel/dentin layer, significantly decreased VH (P<0.05) on the bottom surface of all composite groups. CONCLUSION: The results of this study showed that light-curing attenuation of dental structures negatively affect the micro-hardness of composite resins.

Slumping during sculpturing of composite materials.

OBJECTIVES: This study investigated the slumping characteristics of four composite materials during sculpturing prior to their polymerization. METHODS: Four different composite materials were used to measure shape deformation due to slumping. Silicon impressions of the occlusal plane of three different molars were used as a mould for the composite samples. The surface of the samples was digitized with a laser scanner (400 slices, lateral resolution: 25 microm). Scans were made after 1-4 min. The 3D data sets were numerically superimposed with matching software and differences were calculated relative to the baseline measurement. RESULTS: The amount of surface deformation increases with increasing observation time. The average coefficient of variation was 0.2. The largest mean amount of slumping was observed for ELS with tooth mould 1 (150.0 microm), and for Clearfil Majesty with tooth mould 2 (98.3 microm) and mould 3 (42.8 microm). Miris 2 Dentin and Synergy D6 Enamel were rather similar and seem to exhibit little deformation. The slump flow of ELS and Clearfil Majesty was up to 400% higher than the formers. The deformation could be sorted in the following order "mould 3"<"mould 2"<"mould 1" for all materials and all observation time. There was a significant influence (p<0.05) of the three factors, time, mould and composite type (ANOVA). SIGNIFICANCE: This specific method provides a reproducible approach for the assessment of the handling characteristics of composite materials. The results can identify slumping differences and assist in collecting information about the feasibility of a material for certain indications.

Cytotoxicity of composite materials polymerized with LED curing units.

The proper intensity and illumination time of a curing light is of great importance for the complete polymerization of resin composites and long-lasting resin composite restorations. Inadequately cured resin composites can have a cytotoxic effect on pulp tissue by releasing unreacted monomers. This study determined whether there is any difference in cytotoxicity between composite materials illuminated with different curing modes of LED curing units. Thin layers of two composite materials were polymerized using three different modes of the Bluephase C8 LED curing unit: a high intensity mode (HIP-800 mW/cm2, 20 seconds), a soft-start mode (SOF-650 mW/cm2 first 5 seconds, 800 mW/cm2 next 25 seconds) and a low intensity mode (LOP-650 mW/cm2, 30 seconds). Lymphocyte cultures were treated with both polymerized and unpolymerized composites using one of the modes stated above. Cells were analyzed using the trypan blue exclusion test, the acridine orange/ethidium bromide dying technique and an alkaline comet assay. Significant cytotoxicity was observed for 120 mg of unpolymerized composites and those polymerized with the HIP polymerization mode. A significant level of DNA damage was detected for 120 mg of unpolymerized composites. However, curing via the LOP program exhibited the lowest genotoxicity. Longer curing time with lower intensity results in less cytotoxicity than shorter curing exposure using a higher intensity of light emitted from the curing light source.

Toxicology of Pre-heated Composites Polymerized Directly and Through CAD/CAM Overlay.

OBJECTIVES: The aim was to compare cytotoxicity/genotoxicity of pre-heated composites polymerized through CAD/CAM overlays on isolated human peripheral blood lymphocytes. MATERIAL AND METHODS: A microhybrid (Z100, 3M ESPE) and nanofilled composite (Filtek Supreme Ultra, 3M ESPE) were heated in a heating unit (Calset, AdDent Inc.) at different temperatures: 37 oC, 54 oC, and 68 oC. A small amount of heated composite was placed in a cylindrical mold (6mm diameter; 0.65mm thick), covered with a Mylar sheet, pressed and light-cured directly and through 2 mm thick CAD/CAM ceramic-reinforced polymer (CRP)(LAVA Ultimate, 3M ESPE) or CAD/CAM lithium disilicate ceramic (LDC)(e.max, Ivoclar/Vivadent) overlay. After curing, the specimens were immediately placed in a prepared lymphocyte cell culture. Cytotoxicity was assessed using a dye exclusion method by simultaneous staining with ethidium bromide and acridine orange, aimed to determine percentages of viable, apoptotic and necrotic cells. Genotoxicity was studied using alkaline comet assay. RESULTS: For Z100, the highest percentage of viable cells is recorded at T1 (93.7%) after direct light curing, followed by light curing through CRP (92.3%) and through LDC (91.7%T1,T3). For Filtek Supreme Ultra, the highest percentage of viable cells is recorded while curing through CRP (91.0% T2), followed by LDC (90% T1,T3) and direct light curing (88.7%T2). CONCLUSION: For both tested materials, preheating the procedure at T1 and T2 may be the procedure of choice. In terms of genotoxicity, preheating at T3 may not be suggested.

In Vitro Biocompatibility of Preheated Giomer and Microfilled-Hybrid Composite.

OBJECTIVE: The aim of this study was to evaluate cytotoxic potencies of two light cured composite materials after heating on different temperatures and cured directly and through CAD/CAM overlay. MATERIALS AND METHODS: Composite materials (microfilled-hybrid Gradia Direct Posterior and Beautifil II) were heated in a Calset warming unit at three different temperatures (T1:37°C, T2:54°C, T3:68°C). A small amount of heated composite material was placed in a round mold (diameter 6mm; 0.65mm thick), covered with Mylar sheet, pressed and polymerized with Bluephase LED unit. One group of samples were polymerized directly, and the other group through 2mm thick CAD/CAM ceramic-reinforced polymer (CRP) and CAD/CAM lithium disilicate ceramic (LDC) overlay for 20 and 40 seconds. The polymerized samples were placed immediately after curing in a lymphocyte cell culture. The viability of peripheral blood lymphocytes was evaluated using a dye exclusion technique by simultaneous staining with ethidium bromide and acridine orange. Quantitative assessments were made by determination of the percentage of viable, apoptotic and necrotic cells. The Pearson chi-square test was used for statistical analysis. RESULTS: In case of 20 seconds polymerization, the highest number of viable cells polymerization were recorded when materials were heated at 37°C (T1), while in case of 40 seconds polymerization, the highest number of viable cells were recorded when the materials were heated at 54°C (T2). The samples polymerized through CAD/CAM overlays showed less cytotoxicity than samples polymerized directly. CONCLUSION: Apart from composite material composition, the cell viability was also influenced by curing time, temperature of pre-heating and polymerization pattern.

Visualization of marginal integrity of resin-enamel interface by holographic interferometry.

This study determined whether it was possible to detect deformations and fractures in dental hard tissues or in composite material from internal stresses using double-exposure holographic interferometry. On the proximal side of eight intact human permanent premolars, a direct Class II cavity was prepared and restored with a self-etching adhesive (Clearfil SE Bond) and Tetric Ceram, a resin composite. In five of the specimens, Tetric Flow was used as an elastic layer. The samples were illuminated using a helium-neon laser beam, and the holograms of samples were recorded using Agfa 10E75 photographic plates. Hologram reconstructions were captured with an 8-bit monochrome CCD camera and qualitatively analyzed. Deformations and fractures appeared as fringe patterns on all interferograms, where the distribution of fringes provided location information, while the density of fringes gave the amplitude information. Greater fringe densities were observed in samples treated without a flowable composite.

Composite photopolymerization with diode laser.

Under clinical conditions, the time needed for the proper light curing of luting composites or the multi-incremental buildup of a large restoration with halogen curing units is quite extensive. Due to the development of high power curing devices, such as argon lasers and plasma arc lights and, in order to decrease curing time, halogen and LED devices have developed a high intensity polymerization mode. This study compared the degree of conversion using Fourier Transform Infrared Spectroscopy (FT-IR) of two composite materials: Tetric Ceram and Tetric EvoCeram polymerized with three polymerization modes (high, low and soft mode) of a Bluephase 16i LED curing unit and blue diode laser intensity of 50 mW on the output of the laser beam and 35 mW/cm2 on the resin composite sample. Descriptive statistic, t-test, ANOVA, Pearson Correlation and Tukey Post hoc tests were used for statistical analyses. The results show a higher degree of conversion for the polymerization of composite samples with all photopolymerization modes of the LED curing unit. However, there is no significant difference in the degree of conversion between the LED unit and 50-second polymerization with the blue diode laser. Tetric EvoCeram shows a lower degree of conversion regardless of the polymerization mode (or light source) used.

Prevalence of periodontal diseases in Zagreb population, Croatia, 14 years ago and today.

The aim of this study was to assess prevalence of periodontal diseases within Zagreb adult population in 2000. The sample comprised of 412 examinees of both sexes and all age groups. World Health Organization (WHO) methodology and Community Periodontal Index (CPI), (1997) were used. The data gained was statistically assorted and compared with the data from previously conducted research in 1986. Results showed relatively high prevalence of periodontal diseases. No healthy periodontium was recorded in the 45-and-above age group. Shallow periodontal pockets was registered in 12% of nineteen-year-olds, whereas this symptom was very evident in 45-54 age group (45.7%) and in older than 65 (48.2%). Over 90% of participants had insufficient oral hygiene and 80% required initial periodontal therapy. Approximately 20% needed complex periodontal treatment. Comparison of this data with the previous 1986 research showed improvement of periodontal status in up-to-44 age group due to more healthy persons and more subjects with the initial stages of disease. The possible reason for periodontal health improvement in the last 14 years, evident specially in younger age groups, were the effects of large preventive program measures conducted on schoolchildren in Croatia in 1980-ties and terminated in 1990-ties when the war in Croatia started. Following studies are needed to monitor whether deterioration in oral health will occur regarding to absence of organized preventive programs since 1990-ties.

Comparison of composite curing parameters: effects of light source and curing mode on conversion, temperature rise and polymerization shrinkage.

This study analyzed the degree of conversion, temperature increase and polymerization shrinkage of two hybrid composite materials polymerized with a halogen lamp using three illumination modes and a photopolymerization device based on blue light emitting diodes. The degree of conversion of Tetric Ceram (TC) (Ivoclar Vivadent) and Filtek Z 250 (F) (3M/ESPE) was measured by Fourier transformation infrared spectroscopy at the surface and 2-mm depth; temperature rise was measured by digital multimeter, and linear polymerization shrinkage was measured during cure by digital laser interferometry. Composite samples were illuminated by quartz-tungsten-halogen curing unit (QTH) (Astralis 7, Ivoclar Vivadent) under the following modes: "high power" (HH) 40 seconds at 750 mW/cm2, "low power" (HL) 40 seconds at 400 mW/cm2 and "pulse/soft-start" (HP) increasing from 150 to 400 mW/cm2 during 15 seconds followed by 25 seconds pulsating between 400 and 750 mW/cm2 in 2-second intervals and by light emitting diodes (LED) (Lux-o-Max, Akeda Dental) with emitted intensity 10 seconds at 50 mW/cm2 and 30 seconds at 150 mW/cm2. A significantly higher temperature increase was obtained for both materials using the HH curing mode of halogen light compared to the HP and HL modes and the LED curing unit after 40 seconds. Significantly lower temperature values after 10-second illumination were obtained when LED was used compared to all halogen modes. For all curing modes, there was no significant difference in temperature rise between 20 and 40 seconds of illumination. Results for the degree of conversion measurements show that there is a significant difference in the case of illumination of resin composite samples with LED at the surface and 2 mm depth. For polymerization shrinkage, lower values after 40 seconds were obtained using LED compared to QTH.

Esthetic reconstruction of teeth in patient with dentinogenesis imperfecta--a case report.

Dentinogenesis imperfecta (DI) is the result of a dominant genetic defect and affects both the deciduous and permanent dentitions. It is characterized by opalescent teeth composed of irregularly formed and undemineralized dentin which obliterates pulp chamber and root canal. DI can appear as a separate disorder or with osteogenesis imperfecta (OI). The teeth with DI show a grayish-blue to brown hue with dislodged enamel, dysplastic dentine with irregular dentinal tubules and interglobular dentine, short roots and pulpal obliteration, which all may lead to rapid and extensive attrition which require adequate crown reconstruction. The aim of this study was to show a reconstruction of frontal teeth in upper jaw with direct composite veneers in young adult patient with DI.

Measurement of linear polymerization contraction using digital laser interferometry.

Polymerization shrinkage is an unavoidable consequence of resin composite photopolymerization and is one of the most important factors in determining the clinical quality and durability of composite filling. Many different methods of measuring polymerization shrinkage are described in the literature. Digital laser interferometry is a method that enables direct observation of polymerization shrinkage in real time. This study used the digital holographic interferometry method to measure the linear polymerization contraction of composite materials: Tetric Ceram (Vivadent), Spectrum TPH (Dentsply) and Valux Plus (3M Dental Products) polymerized with three different curing modes of the Elipar Trilight (ESPE) halogen curing unit. The highest polymerization contraction was recorded by "standard mode" (ETS) (1.24 +/- 2.66% lin), and the lowest by "medium mode" (ETM) (0.40 +/- 0.41% lin) during 40 second illumination. The "exponentional mode" (ETE) showed the highest expansion during the first 10 seconds of illumination. Curing units with initial low intensity enable better inner adaptation of composite material, preventing the detachment of material from dentin during polymerization and avoiding the negative consequences of polymerization shrinkage.

Caries and oral hygiene in children in postwar Novi Travnik (Bosnia and Herzegovina) and Zabok (Croatia).

The study was performed in 1997 and involved school children between the age of 6 and 12 in Novi Travnik, Bosnia and Herzegovina (n = 203) and Zabok, Croatia (n = 132). OHI-S (Simplified Oral Hygiene Index by Green-Vermillion) and DMF (Decayed, Missing, Filled) index were used as main outcome measures. Prewar data were taken from the respective literature. The value of the DMF/dmf (PERMANENT/deciduous teeth) for six-year-olds in Novi Travnik of the period before the war was: d = 5.6, m = 0.4, f= 0.6 and D = 0.3, F = 0.1 and the average DMF index of twelve-year-olds for the same period were 6.5. The DMF/dmf index in 1997 in Novi Travnik was: d = 9.4+/-4.4; m = 0.7 +/-1.1; D = 1.9+/-1.2 and average DMF index of twelve-year-olds was 9.0+/-4.16. The DMF index of twelve-year-olds in Zabok in 1990 was 3.4 and 4.1+/-2.1 in 1997. Total DMF index for all the examined ages in 1997 for Zabok was 6.1+/-3.7 and for the examinees in Novi Travnik 10.5+/-4.1 (p<0.001). Similarly, the OHI-S in 1997 for Zabok was 1.0+/-0.7 whereas 1.7+/-0.7 (p<0.001) in Novi Travnik. In comparison to prewar data, DMF index in 1997 was considerably higher. Increase of DMF index was higher in Novi Travnik than in Zabok, which can be attributed to the war and wartime conditions.

Shrinkage evaluation of composite polymerized with LED units using laser interferometry.

OBJECTIVES: Composite resin materials shrink during polymerization regardless of curing unit or polymerization program used. However, different polymerization programs lead to different shrinkage percentages. The aim of this study was to evaluate linear polymerization shrinkage for five composite materials polymerized with curing modes of two LED curing units. METHOD AND MATERIALS: Bluephase C5 (500 mW/cm2, 20 seconds) and Bluephase C8 (high-power mode-800 mW/cm2, 20 seconds; and soft-start mode-650 mW/cm2 for the first 5 seconds, and 800 mW/cm2 for the next 15 seconds) (both curing units by Vivadent) were used for composite resin photopolymerization. The materials used were two fine-particle hybrid composite resins (Tetric Ceram and Artemis) and a nanohybrid composite (Tetric EvoCeram) of different shades (all by Vivadent). Polymerization shrinkage was recorded during each second of the polymerization process using laser interferometry. The results were analyzed by ANOVA, and Tukey post hoc test was used for finding significance levels. RESULTS: The highest shrinkage values were obtained in the case of composite polymerization using the high polymerization mode of Bluephase C8 curing unit (0.61% for Tetric EvoCeram A1 and A3 and 0.69% for Artemis A2), while the lowest results were observed with the soft-start mode of Bluephase C8 LED (0.48% for Artemis A2, 0.41% for Tetric Ceram A3, and 0.35% for Tetric EvoCeram A3.5) and Bluephase C5 curing unit (0.40% for Tetric Ceram A1 and 0.44% for Tetric EvoCeram A3.5). Artemis A2 showed the greatest overall sample dimension change, regardless of the light-curing source used. The initial expansion was recorded for all composite resins and curing modes during the first 4 to 9 seconds of illumination. CONCLUSION: Negative consequences of polymerization shrinkage and temperature rise can be diminished by applying a polymerization program with lower initial light intensity, which prolongs the pregel phase of the polymerization process.