Temperature changes of pulp chamber during in vitro laser welding of orthodontic attachments.
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ABSTRACT:
SUBMITTER: Isman E
PROVIDER: S-EPMC3914460 | biostudies-other | 2014
REPOSITORIES: biostudies-other
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Project description:The aim of this in vitro study was to compare the temperature rises in the pulp chamber and time spent with different techniques for orthodontic resin adhesive removal.Adhesive removal was performed in 20 extracted human maxillary second premolars with five techniques: high-speed tungsten carbide burs with water-cooling (BurH-cool) and without cooling (BurH), low-speed carbide burs (BurL), low-speed aluminum-oxide discs (DiscL), and low-speed fiberglass burs (BurFGL). Pulp chamber temperature was measured with a thermocouple probe and time spent was recorded with a digital stopwatch. Comparisons of temperature rise and time between the techniques were performed with Analysis of variance and Tukey's Honestly test. Correlation between variables was investigated with Pearson's correlation coefficient.Temperature rise and time were statistically different between techniques and showed a positive correlation between them (r=0.826) (P<0.01). BurH-cool provoked the lowest temperature rise and BurFGL the highest (P<0.01). Temperature rises were higher with DiscL than with BurH and BurL (P<0.01), which showed no statistical differences between them (P>0.05). The fastest technique was BurH-cool followed by BurL, BurH, DiscL and BurFGL (P<0.01).BurH-cool, BurH and BurL are safe adhesive removal techniques, whereas DiscL and BurFGL may damage pulp tissues. Time spent on adhesive removal has direct effect on temperature rise in the pulp chamber.
| S-EPMC5527211 | biostudies-other
Project description:IntroductionAn increase in the temperature of the pulp chamber occurs during polymerisation of all types of light-curing resin-containing restorative materials, due to both the exothermic reaction of the material and the energy absorbed during the curing process. Increase in temperature of the pulp chamber of primary teeth during the curing process or the thermal conductivity properties of coloured compomers (CCs) have not yet been investigated in detail. The aim of the present study was to investigate the increase in pulpal temperature in primary teeth during curing of CCs.Materials and methodsA Class-II cavity was prepared on the extracted primary mandibular second molar. Pulpal microcirculation of the tooth was performed using an experimental mechanism. The study included 15 groups and 10 experiments in each. Seven different CCs: pink, blue, gold, silver, orange, lemon, green, respectively from two different manufacturers (Groups 1-7: Twinky Star; VOCO, Cuxhaven, Germany. Groups 8-14: Nova Rainbow; IMICRYL, Konya, Turkey.) and a tooth-CC (Group 15: Dyract XP; DENTSPLY, Weybridge, UK.) were applied in prepared cavity. In all groups the compomers were light cured for 40 s. Intrapulpal temperature changes (Δt) in 20th and 40th second were recorded. In Group-15 the Δt values in 10th second were also recorded as per the manufacturer's instructions. The Kruskal-Wallis test and the Mann-Whitney-U test were used for statistical analyses.ResultsAt the end of 40-s irradiation time, the orange, lemon and green colours of Nova Rainbow resulted in significantly lower Δt values than the same colours of Twinky Star (p = 0.0001), and silver, blue, lemon, green, orange, and pink CCs of Nova Rainbow and the blue and silver shades of Twinky Star demonstrated lower Δt values than the reported critical temperature increase (5.5 °C).ConclusionAn increase in the irradiation time consequently led to an increase in the intrapulpal temperature. Therefore, manufacturers should focus on production of new CCs with shorter polimerization time.
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Project description:This article presents the results of steel-sheet lap-joint-welding using laser beam radiation. The use of a laser beam and keyhole effect for deep material penetration in lap joint welding was presented. Thermodynamic mechanism of laser welding is related to material properties and process parameters. Estimation of welding parameters and joint properties' analysis was performed through numerical simulation. The article presents a possibility of modeling laser lap-joint welding by using Simufact Welding software based on Marc solver and thermo-mechanical solution. Numerical calculation was performed for surface and conical volumetric heat sources simulating laser absorption and keyhole effect during steel sheet welding. Thermo-mechanical results of fusion zone (FZ), heat-affected zone (HAZ) and phase transformations calculated in numerical simulation were analyzed. The welding parameters for partial sealed joint penetration dedicated for gas piping installations were estimated from the numerical analysis. Low-carbon constructional steel was used for numerical and experimental analyses. A trial joint based on the estimated parameters was prepared by using a CO2 laser. Numerical and experimental results in the form of hardness distributions and weld geometry were compared. Metallographic analysis of the obtained weld was presented, including crystallographic structures and inclusions in the cross section of the joint.
| S-EPMC7287657 | biostudies-literature
Project description:ObjectiveTo evaluate the effectiveness of diode laser gingivectomy as an adjunct to nonsurgical periodontal treatment in the management of periodontal health among patients receiving fixed orthodontic appliance therapy (FOAT).Materials and methodsThirty patients undergoing FOAT with gingival enlargement were block randomized into two treatment groups. The test group received diode laser gingivectomy (940-nm diode laser, ezlase, Biolase Technology Inc) as an adjunct to nonsurgical periodontal treatment. The control group received nonsurgical periodontal treatment only. For both groups, five periodontal parameters were assessed at baseline, 1 month, 3 months, and 6 months: Plaque Index, Gingival Index, bleeding on probing, probing pocket depth, and Gingival Overgrowth Index. Intra- and intergroup variations in the periodontal parameters were determined over time.ResultsBoth groups showed statistically significant improvements in periodontal health over the study period (P < .05). However, significant improvements in periodontal health were evident earlier among the test group subjects (P < .05). The magnitude of improvement in periodontal health compared to baseline was greater in the test group than in the control group for Gingival Overgrowth Index at 1 month (P < .001) and 3 months (P < .05), Gingival Index at 3 months (P < .05) and 6 months (P < .05), and probing pocket depth at 1 month (P < .05).ConclusionsNonsurgical periodontal management with or without the adjunct use of lasers can be effective in the management of gingival health problems among patients receiving FOAT. The adjunctive use of lasers can produce an earlier and greater improvement in gingival health.
| S-EPMC8805525 | biostudies-literature
Project description:To biologically explain why the orthodontic treatment does not induce pulp necrosis and calcific metamorphosis of the pulp, this paper presents explanations based on pulp physiology, microscopy and pathology, and especially the cell and tissue phenomena that characterize the induced tooth movement. The final reflections are as follows: 1) the orthodontic movement does not induce pulp necrosis or calcific metamorphosis of the pulp; 2) there is no literature or experimental and clinical models to demonstrate or minimally evidence pulp alterations induced by orthodontic movement; 3) when pulp necrosis or calcific metamorphosis of the pulp is diagnosed during orthodontic treatment or soon after removal of orthodontic appliances, its etiology should be assigned to concussion dental trauma, rather than to orthodontic treatment; 4) the two pulp disorders that cause tooth discoloration in apparently healthy teeth are the aseptic pulp necrosis and calcific metamorphosis of the pulp, both only induced by dental trauma; 5) the concussion dental trauma still requires many clinical and laboratory studies with pertinent experimental models, to increasingly explain its effects on the periodontal and pulp tissues.
| S-EPMC6150703 | biostudies-other
Project description:BackgroundOrthodontic treatment is widely used to treat malocclusion. However, the influence of treatment on the oral microbiome remains unclear. In this study, we investigated salivary microbial changes in patients undergoing orthodontic treatment.MethodsIn total, 19 orthodontic patients participated in this study. Saliva samples were collected at the following three timepoints: before (T0) and 3 months (T1) and 6 months (T2) after the placement of orthodontic appliances. High-throughput sequencing was performed based on the 16S rRNA gene V4 region.ResultsThe phyla of Proteobacteria, Bacteroidetes, Firmicutes, Actinobacteria and Fusobacteria were predominant. Observed Species, Chao1 and ACE, which represent α diversity, were significantly decreased at T1 and subsequently increased at T2. In addition, the β diversity at T1 based on the Bray-Curtis distances differed from T0 and T2. The relative abundances of Prevotella, Porphyromonas and Peptostreptococcus were decreased with treatment, whereas those of Capnocytophaga and Neisseria exhibited the opposite results. In total, 385 of 410 operational taxonomic units were shared at T0, T1 and T2. The co-occurrence networks with hub nodes at T1 were the most complex.ConclusionOrthodontic treatment temporarily affected the saliva microbial community. This dynamic alteration in species did not induce deterioration in oral health. Oral hygiene instructions were necessary and should be emphasized during each visit. Further studies with longer observation periods and more participants are required.
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Project description:An in vitro gastrointestinal digestion model was applied to investigate the effect of digestion on the phenolic compounds and antioxidant capacity of Artocarpus heterophyllus Lam. (jackfruit) pulp. The total phenol content (TPC) was determined using Folin-Ciocalteu method, and the antioxidant activities were evaluated by DPPH and ABTS assays. Phenolic compounds were analyzed using ultra-performance liquid chromatography coupled with electrospray ionization, followed by quadrupole time-of-flight mass spectrometry (UPLC-ESI-Q-TOF-MS/MS). The results showed that TPC was significantly higher after gastric digestion. Thirty phenolic compounds (hydroxybenzoic acids and derivatives, hydroxycinnamic acids and derivatives, and flavonoids) were identified. The antioxidant activities of the digested samples varied with the TPC, and there was a correlation between antioxidant activity and TPC. The present study implies that gastrointestinal digestion may improve TPC and increase the amount of free phenolic compounds, mainly related to changes in pH value and digestive enzymes.
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