Tooth Surface Roughness Research Articles

Comparison of the effect of sodium bicarbonate and glycine air polishing systems on tooth surface roughness: An atomic force microscopic analysis.

A variety of prophylactic materials are used in the dental office for the removal of stains and calculus. To evaluate tooth surface changes caused by the application of air abrasive powders (sodium bicarbonate, SBAP and glycine air powder, GPAP) along with scaling and root planing (SRP), under atomic force microscope (AFM) and to analyze the histological soft tissue changes caused by these agents, using light microscopy. This study was conducted in two phases: in vitro and in vivo. In the in vitro phase, hard tissue analysis was done under AFM following air powder polishing. Eighteen extracted teeth were chosen. SRP and tooth sectioning were carried out. Subsequently, each section of the tooth was mounted on a glass plate with self-cure acrylic resin and air polished using SBAP and GPAP. In the vivo phase, the soft tissue was analyzed under a light microscope for surface roughness. A biopsy specimen was taken from patients who had received phase I therapy, and flap surgery was planned using a modified Widman flap technique. This study compared surface changes in enamel and cementum, under AFM, as indicated by RA after SRP, SRP and SBAP, and SRP and GPAP; comparisons were then drawn across the three groups. The mean AFM values were 108.5 and 144.7, 102.7 and 81.7, and 95.6 and 7.4, at the crown and root, for SRP, SRP and SBAP, and SRP and GPAP interventions, respectively. GPAP was the least rough on soft tissues. SBAP and GPAP were better than hand instrumentation as indicated by AFM and histological section analysis.

In Vitro Effect of Acidic Challenges on the Physical Properties of Dental Prosthesis Artificial Teeth

Objective: To evaluate the effect of immersion and acid challenge with cola drink on color change ( Δ E), Vickers hardness (VHN) and surface roughness (Ra) of artificial acrylic resin teeth. Material and Methods: The artificial teeth were divided into 6 groups (n= 8): TC (Trilux/Control), BC (Biotone/Control), TAC (Trilux/Acid challenge), BAC (Biotone/Acid challenge), TI (Trilux/Immersion) and BI (Biotone/Immersion). The teeth were embedded in acrylic resin and the labial side was serially polished to provide appropriate flat surface. The samples of TC, BC, TI, BI groups were immersed in artificial saliva and cola drink (coke) for 7 days, respectively. The acid challenge was performed with immersion of samples in coke for 5 min, and subsequently immersion in artificial saliva for 2h. This cycle was repeated at 4 times/day, during 7 days. The tests of VHN, Δ E and Ra were analyzed before and after the challenge and immersion groups. Data was analyzed by ANOVA, Tukey and T test ( α = 0.05) . Results: There was no difference in Ra values between groups after treatments. However, there was a decrease in VHN for all groups. BI (19.2 ± 0.3) presented significantly lower hardness than BAC (19.5 ± 0.9) and BC (20.2 ± 0.5). Groups BI (2.18 ± 0.41) and TI (1.50 ± 0.43) had statistically higher Δ E compared to the other groups . Conclusion: The hardness of resin teeth decreased after acid challenges, but the roughness surface was not affected. The color was more affected by the times of exposure in cola beverage and remineralization in artificial saliva, which were associated to the material degradation.

Effect of acidic beverages on surface roughness and color stability of artificial teeth and acrylic resin.

PURPOSEThe aim was to evaluate the effect of four acidic beverages on the roughness (Ra) and color change (ΔEab) of two brands of artificial teeth and a heat-polymerized acrylic resin (HPAR) for use in a prosthetic base.MATERIALS AND METHODSAll materials were divided into 5 groups, according to the used acidic beverage (artificial saliva - control, red wine, orange juice, coke-based, and lemon juice-based soft drink). The immersion process was divided into two stages: T1 - immersion in the acidic solutions for 10 minutes for 14 days; T2 - after T1, the samples were immersed in grape juice for 14 days. The Ra of the samples was evaluated in a rugosimeter and the ΔEab in a spectrophotometer, before and after the immersions. The analysis of variance of one (ΔEab) and two factors (Ra) and Tukey were performed (α=.05).RESULTSThere was a statistical difference for roughness after immersion (T1) for Trilux and Tritone teeth, regardless of the acid solution. For Trilux teeth, all acid solutions increased Ra (P<.05). For Tritone teeth, only the coke-based soft drink did not statistically change Ra. Grape juice (T2) altered Ra only of artificial teeth (P<.05). The color was changed for all materials, after T1 and T2.CONCLUSIONIn general, the acidic solutions changed the Ra and ΔEab of HPAR and artificial teeth after T1. The grape juice altered the roughness only of the artificial teeth, promoting a clinically acceptable color change in the materials.

PENGARUH APLIKASI GEL THEOBROMINE TERHADAP KEKASARAN PERMUKAAN EMAIL GIGI DESIDUI PASCA DEMINERALISASI

Background: Caries is common problem found in children. Caries prevalences increased mainly in developing countries such as Indonesia. Theobromine is an alkaloid compound in metilxantin group which can be found in the cocoa bean. Theobromine is believed to prevent caries by restoring the rough surface of email as the result of demineralisation. This research is aimed to analyze the effect of theobromine gel on the surface roughness of deciduous teeth after demineralization. Method: It was laboratory experiments. Sample of research were 20 incisive cariesfree deciduous teeth. Samples divided into fve groups of treatments (concentration of gel theobromine 1%, 2%, 3%, 4%, and 5%). Each group consists of 4 samples. All samples were demineralized with 37% phosphoric acid for 60 seconds. Samples were immersed in artifcial saliva for 60 minutes in temperature 37⁰. Roughness examination before and after treatment was conducted using Surface Roughness Tester. Result: This experiment showed that surface roughness is decreasing after treated by fve different concentrations of theobromine. There is a signifcant difference compared to other treatments (p<0,05). Conclusion: Theobromine can be used as one of the caries preventive products. The effective concentration of gel theobromine to decrease surface roughness of teeth email is 5%.

Influence of different types of whitening tooth pastes on the tooth color, enamel surface roughness and enamel morphology of human teeth

Background: Tooth whitening usually includes the direct use of gels containing carbamide or hydrogen peroxide on the tooth enamel surface through a wide variety of products formulas. A generally new advancement in whitening of teeth uses the significant importance of the tooth color shift from yellow to blue in delivering a general enhancement in the observation of tooth whiteness. The aim of the current work was to measure the tooth whitening effects, surface roughness and enamel morphology of six different types of blue covarine-containing and blue covarine-free toothpastes using in vitro models. Methods: A total of 70 sound extracted human premolars were randomly and equally divided into seven groups, and each subjected to tooth brushing using different toothpastes. Tooth color and enamel surface roughness were measured before and after the brushing procedure using a white light interferometer, and scanning electron microscopy (SEM) was used to assess tooth surface after the procedure. Results: Toothpaste containing blue covarine resulted in the greatest improvement in tooth color amongst all groups as well as a statistically significant color difference when compared to blue covarine-free toothpaste. Furthermore, blue covarine-containing toothpaste resulted in fewer morphological changes to the enamel surface. This was confirmed with SEM images that showed smooth enamel surfaces with fine scratches. Conclusions: The results from the present study show that blue covarine containing toothpastes are reliable, effective in tooth whitening and produce less surface abrasion when compared to blue covarine-free toothpastes.

Influence of different types of whitening tooth pastes on the tooth color, enamel surface roughness and enamel morphology of human teeth.

Background: Tooth whitening usually includes the direct use of gels containing carbamide or hydrogen peroxide on the tooth enamel surface through a wide variety of products formulas. A generally new advancement in whitening of teeth uses the significant importance of the tooth color shift from yellow to blue in delivering a general enhancement in the observation of tooth whiteness. The aim of the current work was to measure the tooth whitening effects, surface roughness and enamel morphology of six different types of blue covarine-containing and blue covarine-free toothpastes using in vitro models. Methods: A total of 70 sound extracted human premolars were randomly and equally divided into seven groups, and each subjected to tooth brushing using different toothpastes. Tooth color and enamel surface roughness were measured before and after the brushing procedure using a white light interferometer, and scanning electron microscopy (SEM) was used to assess tooth surface after the procedure. Results: Toothpaste containing blue covarine resulted in the greatest improvement in tooth color amongst all groups as well as a statistically significant color difference when compared to blue covarine-free toothpaste. Furthermore, blue covarine-containing toothpaste resulted in fewer morphological changes to the enamel surface. This was confirmed with SEM images that showed smooth enamel surfaces with fine scratches. Conclusions: The results from the present study show that blue covarine containing toothpastes are reliable, effective in tooth whitening and produce less surface abrasion when compared to blue covarine-free toothpastes.

The accuracy of the prediction models for surface roughness and micro hardness of denture teeth.

The paper aimed to compare the performance of artificial neural network (ANN) model with the results of in vitro experiments. For these experiments, maxillary molars of four different denture teeth were subjected to tea, coffee, cola, cherry juice, distilled water. Vickers microhardness and surface roughness values were measured. Subsequently, ANN model for the prediction of microhardness and surface roughness of different denture teeth were examined. A back-propagation ANN has been used to develop a model relating to the amount of microhardness and surface roughness. The independent variables of the model are distilled water, tea, filtered coffee, cola, cherry juice, time and denture teeth. Microhardness and surface roughness were chosen as the dependent variables. According to the results, a neural network architecture having one input layer with ten neurons, two hidden layers with six neurons, one output layer with two neurons and an epoch size of 48 gives better prediction. Prediction models for dental materials could also be supportive for in vitro studies.

Conjugate approach for hypoid gears frictional loss comparison between different roughness patterns under mixed elastohydrodynamic lubrication regime

Abstract This paper compares the frictional loss of hypoid gears between three different tooth surface roughness patterns under the mixed elastohydrodynamic lubrication regime, namely the striated, the isotropic and the less roughed. Conjugate approach contact model for such purpose is proposed, which aids in determination of the parameters input for the lubrication model and construction of wanted tooth surface roughness patterns, by integrating the digital tooth surface technique, the conjugate approach teeth contact analysis and a particular contact search algorithm into a fully integrated contact model. The frictional losses are computed from the upper to the down boundary defined by the load share portion between the film and the asperity in the regime with the varying λ ratio by continuously adding the rotational speed on the geared system. The simulation finds that the frictional loss of the case striated is less than the case isotropic, and the case less roughed has the smallest frictional loss. It also finds that the rotational speed has a significant influence on the film thickness, on the load share, and thus on the frictional loss. Merits are exhibited with this integrated contact model, including good compatibility with lubrication model in passing data, good accuracy and less computation time.

Machining method of large-sized cylindrical worm gears with Niemann profiles using CNC machining center

In this paper, a machining method of large-sized cylindrical worm gears with Niemann profiles using a computer numerical control (CNC) machining center is proposed. For this study, the tooth contact pattern and transmission errors of large-sized worm gear pair with Niemann profiles are analyzed before machining of the worm and worm wheel. Next, the machining conditions of worm are determined calculating each offset distance between the worm axis and the center axis of the end mill, and then the worm is machined by swarf cutting that means machining by the side surface of the end mill. The tooth profiles of worm wheel are modeled using a 3D computer-aided design (3D-CAD) system based on the analyzed results and the worm wheel is machined by swarf cutting through a computer-aided manufacturing (CAM) process. Afterwards, the axial tooth profile of the machined worm, and the tooth surface deviations and surface roughness of the machined worm wheel are measured. Moreover, the experimental tooth contact pattern is compared with analyzed one. As a result, the validity of the proposed machining method of the large-sized worm gears with Niemann profiles using a CNC machining center was confirmed.

Dental Microwear Texture Analysis in Two Ruminants, Japanese Serow (Capricornis crispus) and Sika Deer (Cervus nippon), from Central Japan

Dental microwear texture analysis (DMTA) can be used to quantitatively evaluate tooth surface roughness and has been used to distinguish herbivorous ungulates according to interspecific dietary differences among grazers, browsers, and mixed feeders. Moreover, DMTA has been applied among local populations with intraspecific dietary variation. In general, the tooth surfaces of grazing species/populations are rough, whereas those of browsing species/populations are smooth. Whether DMTA can be used to detect dietary differences among sympatric species is of interest. In the present study, we aimed to use DMTA to explore interspecific differences in diet between two ruminants in Japan—the sika deer and Japanese serow in Nagano Prefecture. We found significant differences in surface roughness parameters between deer and serow. The tooth surfaces of the deer were more undulated with parallel scratches, whereas those of the serow were smoother with pits. These results indicate that the deer consumed abrasive graminoids more frequently than the serow, which is in accordance with previous dietary analyses. However, the two species did not segregate dichotomously but showed a huge overlap in DMTA parameters, implying dietary overlap. The present study shows the potential of DMTA to clarify the foraging ecology of sympatric ruminants from skeletal specimens.

An analytical method for surface roughness prediction in precision grinding of screw rotors

In the process of grinding, rubbing, plowing, and cutting occur successively between abrasive grains and workpiece material as the grinding depth increases. In precision grinding of the screw rotor, small grinding depth is generally introduced, which usually results in plowing. Therefore, it is essential to predict the surface roughness caused by plowing in order to make the process controllable. In this paper, an analytical method for predicting tooth surface roughness of the screw rotor in precision grinding has been proposed. This method takes the following factors into consideration, i.e., distribution law of the grain protrusion heights, variation of grinding depth, velocities and diameters of the screw rotor and grinding wheel at different contact points, and the dressing parameters of grinding wheel. A trajectory projection method has been employed to determine the groove depth and distribution left by the abrasive grains. With the proposed model, the distribution of roughness over the screw rotor tooth surface can be calculated. Verification experiments were conducted with several screw motors produced and surface roughness measured. The comparison results reveal a good agreement between predicted results and experimental results, showing the effectiveness of the proposed method. This study could shed light on the plowing phenomena in precision grinding and could provide great potential in achieving an effective control of the surface roughness.

Study on contact fatigue of a wind turbine gear pair considering surface roughness

Contact fatigue issues become more and more crucial in gear industry as they significantly affect the reliability and service life of associated mechanical systems such as wind turbine gearboxes. The contact fatigue behavior is mostly determined by the mechanical properties of materials and stress fields near the contact area, which is further influenced by the lubrication and surface roughness due to pressure fluctuations. In this study, a numerical model incorporating the lubrication state, tooth surface roughness, residual stress, and mechanical properties of the material is developed to determine the contact fatigue behavior of a megawatt level wind turbine carburized gear. The variations of the hardness and residual stress along the depth were characterized by the Vickers hardness measurement and X-ray diffraction test, respectively. The elastohydrodynamic lubrication theory was applied to predict the contact pressure distribution, highlighting the influence of the surface roughness that stemed from the original measurement through an optical profiler. The stress histories of the studied material points during a complete contact loading cycle were fast calculated using the discreteconcrete fast Fourier transformation (DC-FFT) method. Modified Dang Van diagrams under different working conditions were determined to estimate the contact fatigue failure risk. The effect of the root mean square (RMS) value of the surface roughness on the failure risk at critical material points were discussed in detail. Results revealed that the surface roughness significantly increases the contact fatigue failure risk within a shallow area, and the maximum risk appears near the surface.

A parametric analysis of the surface roughness of teeth shaped by a pinion shaper cutter and guidelines for choosing process parameters

A parametric mathematical model is presented, by which it is possible to determine the machined gear tooth surface topography cut by a pinion shaper cutter. Arbitrary internal or external helical gears designs can be considered, the gear and the shaper cutter must only share a basic rack design. The basic rack has here an elliptical fillet, as it allows fewer tool tooth numbers without the risk of undercut. The machined tooth surface is presented in three dimensions and by surface roughness parameters [Formula: see text], and [Formula: see text]. A novel method to choose cutting parameters and tool design is also presented.

Effects of oral prophylaxis methods on the surface roughness of tooth coloured restorative materials

Introduction: many new aesthetic restorative materials are used in clinical practice to obtain better polishability and wear resistance but their properties and the surface changes that occur after oral prophylaxis are still unknown. Aim of the study: The present study aimed to evaluate the effects of two oral prophylaxes on the surface roughness of three different brands of aesthetic restorative materials. Materials and methods: A total of 90 standardized specimens, were fabricated using a cylindrical plastic mold, 10 mm diameter × 2 mm depth, of three different restorative materials; resin modifiesd glassionomer (RMGIC) (Fuji Filling LC), bioactive ionic resin(Activa Bioactive) and nanofilled resin composite (Filtek™ Z350 XT) 30 specimens of each restorative material, All Specimens were polished with a series of aluminum oxide polishing discs (Sof-Lex). specimens of each restorative materials were randomly divided into three subgroups of 10 specimens according to the treatment it will receive. Group I received no treatment. Group II was polished with rubber cup and proKlene Prophylaxis Paste . Group III was polished with AIRFLOW® Prophylaxis. Surface roughness measurements were performed using ESEM (QUANTA 200, FEI CO., OR, USA), then, data were analyzed by two-way analysis of variance (ANOVA), and mean values were compared by Tukey’s honestly significant difference test (α = 0.05). Results: It was found that surface roughness values were changed significantly between the control, 1st and 2nd evaluations (p < 0.05) for each material and between the two prophylactic methods and control (p < 0.05), showing that the change in surface roughness depended on the type of restorative material and prophylactic treatment. Roughness was significantly higher after the pumice and rubber cup (p < 0.05).Conclusion: Prophylaxis using pumice and rubber cup showed significantly the highest surface roughness of restorative material. The nanofilled composite was the least to be affected.

Ratchetting–multiaxial fatigue damage analysis in gear rolling contact considering tooth surface roughness

Under the combined effect of the tooth surface roughness and heavy load condition, gear materials might experience both the fatigue damage and the ratchetting damage. An elastic-plastic finite element contact fatigue model is proposed considering the optically measured tooth surface roughness and the gear contact geometry. The kinematic hardening constitutive equation and the Jiang and Sehitoglu ratchetting-multiaxial fatigue model are applied, and the contribution of the ratchetting-fatigue damage in the mechanism of gear contact fatigue problems is discussed. Results reveal that the surface roughness can promote the emergence of ratchetting behavior within a very shallow area near surface. Furthermore, the effect of the normal load condition on the ratchetting-fatigue damage is also discussed.

A model to predict initiation and propagation of micro-pitting on tooth flanks of spur gears

Micro-pitting is an early-stage failure mode commonly found in gears. It leads to macro-pitting, spalling, and even tooth fracture failure, which cause destructive damage to gearboxes. A simulation model to predict the initiation and propagation of micro-pitting on tooth flanks of spur gears is presented. The model simulates the actual gear meshing process, considering the time-varying tooth profile. The contact pressure distribution, sliding velocities, rolling velocities, film thicknesses, and shear stresses along the contact line are accurately calculated. A new crack criterion is proposed to predict the initial crack position. A novel wear rate model was developed by considering the influence of crack density to predict the propagation of micro-pitting and the removal of material from the tooth flank. The results of experiments carried out for gear pairs with different tooth tip reliefs and surface roughness showed good agreement with the simulation results. This verified the model validity.

Remineralization effect of varnish on early tooth decay.

Enamel demineralizing can occur due to various conditions, while white spot can be formed as an early tooth decay lesion. If these are neglected, weakened tooth due to enamel demineralizing can become chipped or it can progress into tooth decay. The most commonly used remineralization material is fluoride varnish. This study investigated remineralization and the physical changes of the tooth surface with erosion by using three different types of fluoride varnish. The specimen was prepared by using the anterior tooth of cattle, and early decay lesion was produced by using artificial demineralizing solution. Fluoride varnish was applied to each demineralized surface by using GC, ivoclar, and 3 M products according to the instruction of the manufacturer. Meanwhile, the remineralization degree of the surface after application was identified by using Quantitative Light-induced Fluorescence Detection (QLF-D). In addition, surface roughness before and after application was measured and recorded as Ra values. The surface roughness showed the most decreased value in the 3 M product, while the QLF-D of the early decaying lesion showed remineralization effect in all three products. The 3 M product has the most decreased ΔFmax value. This study demonstrated changes in tooth surface roughness after fluoride varnish application and remineralizing effect of the most commonly used products. Among the three products, 3 M varnish product showed the most favorable results.

Analysis of Surface Roughness of Cold Roll-Beating Tooth

Surface roughness is a key measurement index of the surface quality of the cold roll-beating forming rack, which directly affects the contact conditions, fatigue strength, wear resistance and corrosion resistance of the gear parts when engaging. In view of the surface quality problem of cold roll-beating forming rack, the influence of process parameters on the surface roughness of the tooth wall is analyzed, and the mathematical calculation model of surface roughness is established. The forming test is carried out on the self-designed cold roll-beating equipment to measure the roughness of the sidewall of the forming rack, and the correctness of the calculation model is verified.

Influence of a mouthwash containing Casearia sylvestris on color alteration and surface roughness of tooth

Influence of a mouthwash containing <i>Casearia sylvestris</i> on color alteration and surface roughness of tooth

Dynamical modeling and experimental validation for tooth pitting and spalling in spur gears

Abstract Dynamical modeling of a gear system with faults has been an important research topic for understanding fault features and their associated fault vibration mechanisms. Due to the complicated structures and intricate interactions between the components of the gear system, the fault vibration features and corresponding vibration mechanisms due to tooth pitting and spalling remain mostly unknown. This paper proposes a novel spur gear dynamical model, validated by various experimental tests, to analytically investigate the effects of tooth pitting and spalling on the vibration responses of a gear transmission. The proposed dynamical model considers the effects of tooth surface roughness changes and geometric deviations due to pitting and spalling, and also incorporates Time Varying Mesh Stiffness (TVMS), a time-varying load sharing ratio, as well as dynamic tooth contact friction forces, friction moments and dynamic mesh damping ratios. The proposed gear dynamical model is validated by comparison with responses obtained from experimental test rig under different conditions. Comparisons indicate that the responses of the proposed dynamical model are consistent with experimental results, in both time and frequency domains under different rotation speeds and fault severity conditions.