Dry Enamel Research Articles

Use of laser for uncovering a mandibular retained tooth: case report

This clinical study aimed to describe a case of lower impacted canine to demonstrate the advantages of diode laser for crown exposure during orthodontic treatment. The patient received a surgical intervention by an infra-red diode laser to uncover a retained lower canine. The intervention did not need anesthetic injection and suture apposition, the patient did not refer pain, and the healing process was completed after a week. The diode laser was safe, fast, and easy to use, and the avoidance of bleeding was reached due to its excellent absorption by hemoglobin: this is particularly important considering that, for obtaining a strong adhesion, a bracket must be bonded in a dry enamel surface. The use of an infrared diode laser is a proper approach in the surgery of retained teeth during orthodontic treatment.

Influence of water and protein content on the creep behavior in dental enamel.

The creep behavior of untreated and deproteinized dental enamel in dry and wet state was analyzed by nanoindentation with a spherical tip. Additionally, the influence of the loading rate was investigated. Dry untreated and deproteinized dental enamel only showed minor creep over 100s and deproteinization did not affect the dry enamel's behavior significantly. With slower loading rates some creep already occurs during the loading period, such that the creep displacement during load hold is less than with faster loading rates. Wet untreated and deproteinized enamel showed significantly more creep compared to the dry samples. The differences between the untreated and deproteinized enamel were only minor but significant, revealing that water affects the creep behavior of biological materials such as enamel significantly. The proposed deformation mechanism of naturally porous enamel under compression is compaction of the HAP crystallites and fluid displacement within material underneath the indented area. STATEMENT OF SIGNIFICANCE: This study investigates the creep behavior of untreated and deproteinized dental enamel in dry and wet conditions. It is shown that while the protein content does not affect enamel's behavior significantly, the wet conditions lead to an increased creep in enamel. The proposed deformation mechanism of naturally porous enamel under compression is compaction of the HAP crystallites and fluid displacement within material underneath the indented area. Based on this observation a simple analytical model has been developed, aiming to deepen our understanding of the deformation behavior of biological materials.

INFLUÊNCIA DA MODIFICAÇÃO DA BASE DE COLAGEM E DA CONTAMINAÇÃO SALIVAR NA RESISTÊNCIA DE UNIÃO DE TUBOS ORTODÔNTICOS COLADOS AO ESMALTE HUMANO

The objective of this in vitro study was to assess and compare the shear bond strength of conventional and modified orthodontic tubes bonded to the surface of dry and saliva-contaminated enamel. The sample consisted of 40 human teeth, which were randomly divided into four groups according to attachment base and presence or absence of saliva contamination as follows: Group CB, conventional orthodontic tubes without salivary contamination; Group CB-S, conventional orthodontic tubes with salivary contamination; Groups BM, orthodontic tubes modified by welding a metal mesh to their base without salivary contamination; and Group BM-S, modified orthodontic tubes with salivary contamination. Shear bond strength test was performed in a universal testing machine and analysis of the adhesive remnant index (ARI) by optical microscopy. Two-way ANOVA was used, followed by Tukey’s test at a statistical significance level of 5%. The ARI results were analysed descriptively. There was statistically significant difference between the groups regarding the shear bond strength values, with conventional tubes presenting significantly higher values (P < 0.05). In addition, the presence of salivary contamination interfered negatively with the behaviour of conventional tubes only (P < 0.05). Shear bond strength was not improved by increasing the area of the orthodontic tubes. Moreover, salivary contamination influenced negatively the SBS values, but only when conventional tubes were used.

Observational Study Regarding Two Bonding Systems and the Challenges of Their Use in Orthodontics: An In Vitro Evaluation

The purpose of this in vitro study was to analyze and identify a methodology for the improvement of the shear bond strength of orthodontic brackets bonded with two orthodontic adhesive systems considered to be widely used, Transbond Plus Color Change with Transbond Plus Self-Etching Primer and Fuji Ortho LC with orthophosphoric acid under various enamel conditions: dry, moistened with water and moistened with saliva. The sample size included a group of 120 freshly extracted premolars distributed into six study groups, each one of 20 teeth. A universal testing machine was used to detach the brackets. We determined and compared the strength of the two studied adhesive systems used in different enamel surface conditions. The mean shear bond strength values in groups 1 (TPCC, TSEP, dry), 2 (TPCC, TSEP, water), 3 (TPCC, TSEP, saliva), 4 (Fuji Ortho LC, etched, dry enamel), 5 (Fuji Ortho LC, etched enamel, water) and 6 (Fuji Ortho LC, etched enamel, saliva) were 15.86, 12.31, 13.04, 15.27, 14.14 and 13.11 MPa, respectively. ANOVA test and Student’s t-test showed significant differences between groups. While clinically acceptable shear bond strengths were obtained for all six studied groups, a particular outcome that to the authors’ knowledge has not been documented elsewhere has been obtained: in case of water contamination, it is preferable to use Fuji Ortho LC instead of Transbond Plus.

A Novel Evaluation Method for Detecting Defects of the Bonded Orthodontic Bracket-Tooth Interface.

Background Orthodontic patients are at high risk to develop caries. This study is introducing a clinical method detecting interfacial defects between ceramic brackets and enamel utilizing optical coherent tomography in addition to using the nanoleakage expression in vitro test. Methods Transbond XT primer and moisture insensitive primer (MIP) were bonded to 75 human premolar enamel surfaces and divided into (XTD), (MIPD), and (MIPW) groups. The (XTD) and (MIPD) groups had ceramic brackets bonded to dry enamel surfaces using TransBond and moisture insensitive primers, respectively, while the (MIPW) samples were bonded to moist enamel using moisture insensitive primer. All specimens were examined under crosspolarization optical coherence tomography. Debonding forces of the brackets to 45 teeth (15 teeth/group). 30 bonded specimens (15 specimens/group) were cross-sectioned to detect the nanoleakage expression using scanning electron microscope equipped with energy-dispersive spectroscopy (SEM/EDS). The degree of conversion of the specimens in the experimental groups was tested using attenuated total reflectance Fourier transform infrared spectroscopy (FTIR/ATR). Results Optical coherence tomography detected the interfacial defects between the ceramic brackets and tooth structure. One way ANOVA showed that (XTD) and (MIPD) groups recorded significantly higher bond strength values and less nanoleakage expression when compared to MIPW (p > 0.05). Conclusions Optical coherence tomography can be utilized to detect interfacial adhesive-tooth defects. Dry enamel surfaces improve the quality of the enamel/primer interface (200 words).

Shear bond strength of APC Plus adhesive coated appliance system to enamel in wet and dry conditions: An in vitro study

It is claimed that a hydrophilic primer, called the moisture insensitive primer (MIP), can be used with both dry and wet enamel surfaces. This study sought to assess the shear bond strength (SBS) of APC Plus adhesive coated appliance system to enamel using MIP in wet and dry conditions. This in vitro experimental study evaluated 24 extracted maxillary premolars with intact buccal enamel. The teeth were randomly divided into two groups (n=12), and APC Plus premolar brackets were bonded to their buccal surface using moisture insensitive primer (MIP) under wet and dry enamel conditions. The SBS values were measured by a universal testing machine. The adhesive remnant index (ARI) score was also determined under a stereomicroscope. Data were analyzed using t-test and Mann-Whitney test at P<0.05 level of significance. The SBS in wet condition was significantly lower than that in dry condition (mean value of 18.37MPa versus 25.5MPa, P<0.001). The two groups had no significant difference regarding the ARI scores (P>0.05). However, in both groups, less adhesive was left on the tooth surface. This suggests that bond failure occurred at the adhesive-enamel interface. APC Plus adhesive coated appliance system in combination with hydrophilic MIP can be effective in clinical conditions with high risk of moisture contamination.

Bond strength of orthodontic adhesives to dry and saliva-moistened enamel – a comparative in vitro study

salivamoistened enamel. Design/methodology/approach: One hundred twenty stainless steel brackets were bonded to human mandibular third molars with six materials: Enlight LC® (Ormco Corp), Grengloo® (Ormco Corp), Light Bond® (Reliance Orthodontic Products), Charisma® (Heraeus Kulzer), SmartBond® (Gestenco), and Transbond XT® with MIP® primer (3M Unitek). One half of the specimens in each group (n=10) was bonded to dry enamel, while the other half to saliva-moistened enamel. Bond strength testing was performed with a wire loop loading technique after 30-min incubation in artificial saliva. Failure mode was evaluated using adhesive remaining index (ARI). Findings: No significant differences in bond strength to dry enamel were noted for all composite materials (p&gt;0.05). SmartBond exhibited significantly greater bond strength to moistened enamel (7.10 ± 1.47 MPa) and comparable with other composite materials to dry enamel. Composite materials demonstrated significantly reduced bond strength to saliva-moistened enamel (p&lt;0.001), except for Transbond MIP, whose bond strength was not significantly decreased by saliva contamination (p=0.089). There was not statistically significant difference between bond strength of SmartBond and Transbond to saliva contaminated enamel. A higher incidence of cohesive failures was noted for all materials. Research limitations/implications: Composite light-cured materials provide adequate bond strength to dry enamel. Cyanoacrylate adhesive provides sufficient bond strength only under moist conditions. Transbond XT+MIP has sufficient bond strength to either dry or saliva-moistened enamel. Practical implications: The study evaluated the bonding strength of orthodontic brackets, which is a critical parameter in orthodontics, especially in situations that do not allow for proper isolation from saliva, such as bonding to impacted teeth following surgical exposure. Originality/value: Bond strengths evaluated with loop loading technique in different study environments would help the orthodontist to choose the most effective adhesive for the specific clinical situation.

Influence of self-etch all-in-one adhesives on fissure sealant shear bond strength under contaminated enamel conditions.

To determine the influence of two all-in-one self-etching adhesive systems on shear bond strength of a fissure sealant applied under different enamel surface conditions. A total of 180 bovine enamel specimens were randomly distributed to nine experimental groups, defined by the combination of the sealant application technique (using phosphoric acid, or a self-etching water-based adhesive or a self-etching ethanol and water-based adhesive) and enamel surface conditions (dry enamel, saliva or water contaminated enamel). The specimens were submitted to thermocycling prior to the shear bond strength test. High shear bond strength mean values were obtained with the classic technique for dry enamel (31.47MPa), statistically similar values were obtained when the sealant was combined with a self-etching water-based adhesive, in dry enamel (32.36MPa), and when the sealant was combined with a self-etching water-based adhesive in water contaminated enamel (32.62MPa). Under enamel salivary contamination, the best results were achieved using a water-based adhesive (24.78MPa). In saliva contaminated enamel, the combination of a sealant with a water-based self-etching adhesive can maintain high and satisfactory values of bond strength.

Frictional coefficient during flossing of teeth

ObjectiveThis in-vitro study aimed to develop a technique to measure the frictional forces and determine the frictional coefficient (μ) associated with the rubbing of dental floss against teeth. Incorrect flossing technique and the etiology of grooves at the cementoenamel junction (CEJ) of proximal area of teeth has long been a controversial topic. We hypothesized that the μ between teeth surfaces and dental floss is affected by contact angulation. Materials and methodsTests were conducted using two different types of dental floss (waxed and unwaxed nylon) on different surfaces (enamel, dentine, smooth and rough glass rods) under different moisture conditions (dry and wet). The μ generated by performing C-shape flossing was measured, using the Capstan equation, at constant load (100g) over different flossing contact sliding angulations. In addition, the surface characteristics of intact and used nylon flosses were compared using a scanning electron microscope (SEM). ResultsThe mean μ was highest with a smooth glass rod (0.42±0.11), followed by rough glass rods (0.30±0.07), dry enamel (0.27±0.08), wet enamel (0.23±0.06), then dentine (0.18±0.04). Moreover, higher μ was associated with waxed floss when used against dry enamel, smooth and rough glass rods (P<0.001). At different moisture conditions, waxed floss demonstrated greater μ with dry surfaces (P<0.03). No association was found between μ and dental floss contact angulation. Both floss types showed deterioration after usage; although waxed type exhibited markedly greater deterioration when used on dry surfaces. In conclusion, the magnitude of the μ was found to be influenced by surface roughness, moisture condition, and independent of the contact angulation area during sliding of dental floss. SignificanceIt is important to consider the potential side effects of frictional forces on both tooth surface and dental floss during clinical application.

Nano-indentation of native phytoliths and dental tissues: implications for herbivore-plant combat and dental wear proxies

Tooth wear induced by abrasive particles is a key process affecting dental function and life expectancy in mammals. Abrasive particles may be plant endogenous opal phytoliths, exogene wind-blown quartz dust or rain borne mineral particles ingested by mammals. Nano-indentation hardness of abrasive particles and dental tissues is a significant yet not fully established parameter of this tribological system. We provide consistent nano-indentation hardness data for some of the major antagonists in the dental tribosystem (tooth enamel, tooth dentine and opaline phytoliths from silica controlled cultivation). All indentation data were gathered from native tissues under stable and controlled conditions and thus maximize comparability to natural systems. Here we show that native (hydrated) wild boar enamel exceeds any hardness measures known for dry herbivore tooth enamel by at least 3 GPa. The native tooth enamel is not necessarily softer then environmental quartz grit, although there is little overlap. The native hardness of the tooth enamel exceeds that of any silica phytolith hardness recently published. Further, we find that native reed phytoliths equal native suine dentine in hardness, but does not exceed native suine enamel. We also find that native suine enamel is significantly harder than dry enamel and dry phytoliths are harder than native phytoliths. Our data challenge the claim that the culprit of tooth wear may be the food we chew, but suggest instead that wear may relates more to exogenous than endogenous abrasives.

Evaluation of the Shear Bond Strength of Composite Resin to Wet and Dry Enamel Using Dentin Bonding Agents Containing Various Solvents.

Bonding of composite resin to dentin mandates a wet substrate whereas, enamel should be dry. This may not be easily achievable in intracoronal preparations where enamel and dentin are closely placed to each other. Therefore, Dentin Bonding Agents (DBA) are recommended for enamel and dentinal bonding, where enamel is also left moist. A research question was raised if the "enamel-only" preparations will also benefit from wet enamel bonding and contemporary DBA. The aim of this study was to compare the shear bond strengths of composite resin, bonded to dry and wet enamel using fifth generation DBA (etch and rinse system) containing various solvents such as ethanol/water, acetone and ethanol. The crowns of 120 maxillary premolars were split into buccal and lingual halves. They were randomly allocated into four groups of DBA: Group 1-water/ethanol based, Group 2-acetone based, Group 3-ethanol based, Group 4-universal bonding agent (control group). The buccal halves and lingual halves were bonded using the wet bonding and dry bonding technique respectively. After application of the DBAs and composite resin build up, shear bond strength testing was done. Group 1 (ethanol/water based ESPE 3M, Adper Single Bond) showed highest bond strength of (23.15 MPa) in dry enamel. Group 2 (acetone based Denstply, Prime and Bond NT, showed equal bond strength in wet and dry enamel condition (18.87 MPa and 18.02 MPa respectively). Dry enamel bonding and ethanol/water based etch and rinse DBA can be recommended for "enamel-only" tooth preparations.

Evaluation of micro leakage on etched enamel surface of premolars in total etch technique by applying single bond on dry and wet enamel

Evaluation of micro leakage on etched enamel surface of premolars in total etch technique by applying single bond on dry and wet enamel

Does hydroxyapatite nanoparticles' addition improve enamel esthetics after brackets' debonding ?

Objectives: To evaluate the effect of hydroxyapatite nanoparticles’ addition and determine the utility role of CO2 laser in improving esthetics of enamel surfaces after debonding. Methods: 90 extracted human premolars were used. 10 teeth were used as a control group. Trans bond Plus Self Etching Primer with Trans bond Supreme Low Viscosity Light Cure Adhesive, 3M/Unitek, was used to bond the orthodontic brackets (NU-EDGE.022 ROTH RX.TP Orthodontics) to the labial enamel surfaces. All specimens were stored in artificial saliva for 6 months. Orthodontic brackets were then removed using bracket removing pliers (Ortho Organizers, Carlsbad, USA).Residual composite removed by Sof-Lex finishing discs. The 80 teeth were divided randomly into 4 groups (n=20) according to the protocol of nanoparticles’ addition, 1) no nanoparticles were added, 2) nanoparticles suspended in water and rubbed on the dry enamel surface, 3) nanoparticles suspended in ethanol and rubbed on the etched enamel surface, and 4) nanoparticles suspended in bonding agent [Single Bond 2 adhesive (SB)] & rubbed on the etched enamel surface. Each group assigned into two subgroups (n=10) according to exposure to CO2 laser (9.6μm), where enamel of the first subgroup was irradiated at 3W; 20Hz; 4sec and 212J/cm2 while the other subgroup was not irradiated. The SE bonding agent was applied to the third group after its treatment. Specimens were tested for color changes using Quanta Environmental Scanning Electron Microscope. Data were statistically analyzed using two-way Analysis of Variance (ANOVA) and Tukey’s post-hoc test. Results: highest mean color value was found with no particles. There was no significant difference between group 1 and 2. There was no difference between groups 3 and 4; both showed the statistically significant lowest mean color values. Meanwhile, no significant effect was found between laser and non-laser subgroups. Conclusions: the addition of hydroxyapatite nanoparticles improved the enamel esthetics after brackets debonding.

Enamel Wetness Effects on Microshear Bond Strength of Different Bonding Agents (Adhesive Systems): An in vitro Comparative Evaluation Study.

The purpose of this study was to compare the effect of enamel wetness on microshear bond strength using different adhesive systems. To evaluate microshear bond strength of three bonding agents on dry enamel; to evaluate microshear bond strength of three bonding agents on wet enamel; and to compare microshear bond strength of three different bonding agents on dry and wet enamel. Sixty extracted noncarious human premolars were selected for this study. Flat enamel surfaces of approximately 3 mm were obtained by grinding the buccal surfaces of premolars with water-cooled diamond disks. This study evaluated one etch-and-rinse adhesive system (Single Bond 2) and two self-etching adhesive systems (Clearfil SE Bond and Xeno-V). The specimens were divided into two groups (n = 30). Group I (dry) was air-dried for 30 seconds and in group II (wet) surfaces were blotted with absorbent paper to remove excess water. These groups were further divided into six subgroups (n = 10) according to the adhesives used. The resin composite, Filtek Z 250, was bonded to flat enamel surfaces that had been treated with one of the adhesives, following the manufacturer's instructions. After being stored in water at 37°C for 24 hours, bonded specimens were stressed in universal testing machine (Fig. 3) at a crosshead speed of 1 mm/min. The data were evaluated with one-way and two-way analysis of variance (ANOVA), t-test, and Tukey's Multiple Post hoc tests (a = 0.05). The two-way ANOVA and Tukey's Multiple Post hoc tests showed significant differences among adhesive systems, but wetness did not influence microshear bond strength (p = 0.1762). The one-way ANOVA and t-test showed that the all-in-one adhesive (Xeno-V) was the only material influenced by the presence of water on the enamel surface. Xeno-V showed significantly higher microshear bond strength when the enamel was kept wet. Single Bond 2 adhesive showed significantly higher microshear bond strength as compared with Xeno-V adhesive but no significant difference when compared with Clearfil SE Bond adhesive in dry enamel. Single Bond 2 adhesive showed no significant difference in microshear bond strength as compared with self-etching adhesive systems (Clearfil SE Bond and Xeno-V), when the enamel was kept wet. From the findings of the results, it was concluded that self-etching adhesives were not negatively affected by the presence of water on the enamel surface. The all-in-one adhesive showed different behavior depending on whether the enamel surface was dry or wet. So the enamel surface should not be desiccated, when self-etching adhesives are used.

Comparación de fuerza de adhesión de dos sistemas ortodóncicos con afinidad a la humedad en dos condiciones de superficie del esmalte

The purpose of this study was to compare the shear bond strength of orthodontic brackets with two systems of hydrophilic adhesives: (I) a cyanoacrylate adhesive (Smarbond, International Gestenco) and (II) a composite system (Transbond XT and Transbond™ IPM) in two enamel conditions: dry and artificial saliva contaminated. Materials and methods100 extracted premolars were stored in distilled water at 4 degrees Celsius. The teeth were cleaned, polished, and convenience distributed into 5 groups: (1) composite resin in enamel under dry conditions, (2) cyanoacrylate adhesive in dry enamel condition, (3) composite resin in enamel condition contaminated with artificial saliva before the primer, (4) composite resin enamel condition contaminated with artificial saliva after the primer, and (5) cyanoacrylate adhesive in artificial saliva contaminated enamel condition. The results showed that the adhesive system Transbond XT™ and Transbond MIP obtained the highest values of resistance to debonding in the dry enamel surface. ConclusionsThe adhesive system Transbond XT™ and Transbond MIP I provide an adequate in vitro resistance to debonding in every enamel condition. The system based on cyanoacrylate adhesive Smartbond obtained proper values of resistance to debonding in dry enamel, however it obtained the lowest values in contaminated with enamel artificial saliva conditions, unsuitable for orthodontics, and even some samples were not cemented successfully in vitro under these conditions.

Comparison between the adhesion forces of two orthodontic systems with moisture affinity in two enamel surface conditions

The purpose of this study was to compare the shear bond strength of orthodontic brackets with two systems of hydrophilic adhesives: (I) a cyanoacrylate adhesive (Smartbond, International Gestenco) and (II) a composite system (Transbond XT and Transbond™ IPM) in two enamel conditions: dry and artificial saliva contaminated. Materials and methods100 extracted premolars were stored in distilled water at 4 degrees Celsius. The teeth were cleaned, polished, and convenience distributed into 5 groups: (1) composite resin in enamel under dry conditions, (2) cyanoacrylate adhesive in dry enamel condition, (3) composite resin in enamel condition contaminated with artificial saliva before the primer, (4) composite resin enamel condition contaminated with artificial saliva after the primer, and (5) cyanoacrylate adhesive in artificial saliva contaminated enamel condition. The results showed that the adhesive system Transbond XT™ and Transbond MIP obtained the highest values of resistance to debonding in the dry enamel surface. ConclusionsThe adhesive system Transbond XT™ and Transbond MIP I provide an adequate in vitro resistance to debonding in every enamel condition. The system based on cyanoacrylate adhesive Smartbond obtained proper values of resistance to debonding in dry enamel, however it obtained the lowest values in contaminated with enamel artificial saliva conditions, unsuitable for orthodontics, and even some samples were not cemented successfully in vitro under these conditions.

An Evaluation of Shear Bond Strength of Composite Resin to Enamel under Various Saliva Contaminated Conditions: An in vitro Study

ABSTRACT To produce good adhesion between composite resin and etched enamel surface, it is necessary to form a microscopi- cally intimate contact between them. Contaminants, like saliva, may interfere with such bonding. Salivary contamination may reduce the bond strength between composite resin and the enamel by 40 to 60%. Recent studies have suggested that only rewashing and drying of the etched and saliva contaminated enamel surface is sufficient in restoring bond strength to the normal ideal condition. Purpose To evaluate the effect of saliva contamination on the shear bond strength of composite resin to enamel by using different parameters. Materials and methods The highest mean shear bond strength of composite resin was obtained on the uncontami- nated enamel surface, and the lowest mean shear bond strength was obtained on the saliva contaminated moist enamel surface. Results The mean shear bond strength of composite resin to saliva contaminated, washed and air-dried enamel surface was less than the mean shear bond strength to the dry enamel surface. Conclusion This suggests that only rewashing of the saliva contaminated enamel surface is not enough in achieving bond strength equal to that of the uncontaminated enamel surface. How to cite this article Kale A, Kamra A, Kale Y, Khalikar S. An Evaluation of Shear Bond Strength of Composite Resin to Enamel under Various Saliva Contaminated Conditions: An in vitro Study. Int J Prosthodont Restor Dent 2014;4(4):101-104.

Effect of moisture, saliva, and blood contamination on the shear bond strength of brackets bonded with a conventional bonding system and self-etched bonding system

Background:The success of bonding brackets to enamel with resin bonding systems is negatively affected by contamination with oral fluids such as blood and saliva. The new self-etch primer systems combine conditioning and priming agents into a single application, making the procedure more cost effective.Objective:The purpose of the study was to investigate the effect of moisture, saliva and blood contamination on shear bond strength of orthodontic brackets bonded with conventional bonding system and self-etch bonding system.Materials and Methods:Each system was examined under four enamel surface conditions (dry, water, saliva, and blood), and 80 human teeth were divided into two groups with four subgroups each of 10 according to enamel surface condition. Group 1 used conventional bonding system and Group 2 used self-etched bonding system. Subgroups 1a and 2a under dry enamel surface conditions; Subgroups 1b and 2b under moist enamel surface condition; Subgroups 3a and 3b under saliva enamel surface condition and Subgroup 4a and 4b under blood enamel surface condition. Brackets were bonded, and all the samples were then submitted to a shear bond test with a universal testing machine with a cross head speed of 1mm/sec.Results:The results showed that the contamination reduced the shear bond strength of all groups. In self-etch bonding system water and saliva had significantly higher bond strength when compared to other groups.Conclusion:It was concluded that the blood contamination showed lowest bond strength from both bonding systems. Self-etch bonding system resulted in higher bond strength than conventional bonding system under all conditions except the dry enamel surface.

Effect of moisture on dental enamel in the interaction of two orthodontic bonding systems

The purpose of this study was to assess by means of scanning electron microscopy (SEM) the remaining adhesive interface after debonding orthodontic attachments bonded to bovine teeth with the use of hydrophilic and hydrophobic primers under different dental substrate moisture conditions. Twenty mandibular incisors were divided into four groups (n = 5). In Group I, bracket bonding was performed with Transbond MIP hydrophilic primer and Transbond XT adhesive paste applied to moist substrate, and in Group II a bonding system comprising Transbond XT hydrophobic primer and adhesive paste was applied to moist substrate. Brackets were bonded to the specimens in Groups III and IV using the same adhesive systems, but on dry dental enamel. The images were qualitatively assessed by SEM. The absence of moisture in etched enamel enabled better interaction between bonding materials and the adamantine structure. The hydrophobic primer achieved the worst micromechanical interlocking results when applied to a moist dental structure, whereas the hydrophilic system proved versatile, yielding acceptable results in moist conditions and excellent interaction in the absence of contamination. The authors assert that the best condition for the application of primers to dental enamel occurs in the absence of moisture.

Use of laser in orthodontics: applications and perspectives.

Laser technology got in these years a more and more important role in modern dentistry and, recently, also in orthodontics was proposed the utilization of laser devices. The aim of this work is to describe the utilization of this technology both in soft and hard oral tissues to improve orthodontic treatment. Several cases, with different wavelengths (532, 810, 980, 1064, 2940 and 10600 nm) and in different times of the treatment (before, during and after) are presented. All the cases reported showed, according to the literature, that the use of the laser related to orthodontic treatment offers several advantages when compared with conventional methods. In the soft tissues surgery it allows to reduce or eliminate the use of anesthetic injection, to avoid use of sutures and to bond bracket in dry enamel; associated with orthophosphoric acid, it gives a stronger adhesion of the brackets to the enamel and, in the case of porcelain brackets, it detaches them without damages; at low power (LLLT) it permits to control the pain of the first period after bonding and, by increasing the speed of teeth movement in the bone, reduces the time of the treatment.