Evaluation of zinc-oxide nanocoating on the characteristics and antibacterial behavior of nickel-titanium alloy.

OBJECTIVE: To investigate the effect of ZnO nanocoating on mechanical properties of NiTi orthodontic wires and antibacterial activity. METHODS: 0.016 x 0.022-in NiTi orthodontic wires were coated with ZnO nanoparticles using an electrochemical deposition method with three electrodes system in 0.1M Zn(NO3)2. Mechanical properties and frictional resistance of the coated wires were investigated using an universal testing machine. Antibacterial effect of ZnO coating was also investigated. RESULTS: A stable adhered ZnO nanocoating on NiTi wires was obtained. The coated wires have a significant antibacterial activity against S. aureus, S. pyogens and E. coli, and a reduction of frictional forces by 34%. CONCLUSION: ZnO nanocoating may improve the antibacterial effects of NiTi wires and reduce the frictional resistance. Coating may be implanted in orthodontic practice for faster and safer treatment.

Evaluation of zinc-oxide nanocoating on the characteristics and antibacterial behavior of nickel-titanium alloy

ABSTRACT Objective: To investigate the effect of ZnO nanocoating on mechanical properties of NiTi orthodontic wires and antibacterial activity. Methods: 0.016 x 0.022-in NiTi orthodontic wires were coated with ZnO nanoparticles using an electrochemical deposition method with three electrodes system in 0.1M Zn(NO3)2. Mechanical properties and frictional resistance of the coated wires were investigated using an universal testing machine. Antibacterial effect of ZnO coating was also investigated. Results: A stable adhered ZnO nanocoating on NiTi wires was obtained. The coated wires have a significant antibacterial activity against S. aureus, S. pyogens and E. coli, and a reduction of frictional forces by 34%. Conclusion: ZnO nanocoating may improve the antibacterial effects of NiTi wires and reduce the frictional resistance. Coating may be implanted in orthodontic practice for faster and safer treatment.

RESUMO Objetivos: Avaliar o efeito do nanorrevestimento de óxido de zinco (ZnO) sobre as propriedades mecânicas e propriedades antibacterianas de fios ortodônticos de NiTi. Métodos: Fios 0,016" x 0,022" de NiTi foram revestidos com nanopartículas de ZnO por meio de um método de deposição eletroquímica com um sistema de três eletrodos a 0,1M Zn(NO3)2. Uma máquina universal de testes foi utilizada para avaliar as propriedades mecânicas e a resistência friccional dos fios revestidos. Além disso, também foram analisadas as propriedades antibacterianas do revestimento de ZnO. Resultados: Obteve-se uma aderência estável das nanopartículas de ZnO sobre os fios NiTi. Os fios revestidos apresentaram atividade antibacteriana significativa contra S. aureus, S. pyogens e E. coli, e apresentaram uma redução de 34% na força de atrito. Conclusão: O revestimento com nanopartículas de óxido de zinco pode melhorar as propriedades antibacterianas e reduzir a resistência friccional dos fios de NiTi. Assim, o revestimento dos fios pode ser utilizado na Ortodontia visando tratamentos mais rápidos e seguros.

Evaluation of color changes of white spot lesions treated with three different treatment approaches: an in-vitro study.

OBJECTIVE: To qualitatively and quantitatively assess the color changes effect and the color stability of the resin infiltrant on white spot lesions (WSLs), in comparison with nano-hydroxyapatite (nano-HA) toothpaste and microabrasion. METHODS: WSLs were artificially created on sixty human premolars enamel surfaces and randomly assigned to equal four groups (n = 15 each): nano-HA toothpaste, microabrasion (Opalusture), resin infiltrant (Icon) treatment, or artificial saliva (control group). The color change (ΔE) of each specimen was measured by dental spectrophotometer (Vita Easyshade) at different time points: baseline, after WSLs' creation, after application of treatments, one month, three and six months after treatments application. RESULTS: The ΔE value did not differ significantly for the four groups at baseline measurement before treatment (p> 0.05). Icon resin infiltrant improved the color of WSLs significantly immediately after its application, giving the lowest ΔE value (3.00 ± 0.59), when compared to other treatments (p< 0.001). There were no significant changes in ΔE (p> 0.05) for all groups during the follow up intervals (one month, three and six months after treatments application). CONCLUSION: Resin infiltrant can improve the color of WSLs and restore the natural appearance of enamel better than nano-HA toothpaste and microabrasion.

Evaluation of color changes of white spot lesions treated with three different treatment approaches: an in-vitro study

ABSTRACT Objective: To qualitatively and quantitatively assess the color changes effect and the color stability of the resin infiltrant on white spot lesions (WSLs), in comparison with nano-hydroxyapatite (nano-HA) toothpaste and microabrasion. Methods: WSLs were artificially created on sixty human premolars enamel surfaces and randomly assigned to equal four groups (n = 15 each): nano-HA toothpaste, microabrasion (Opalusture), resin infiltrant (Icon) treatment, or artificial saliva (control group). The color change (ΔE) of each specimen was measured by dental spectrophotometer (Vita Easyshade) at different time points: baseline, after WSLs' creation, after application of treatments, one month, three and six months after treatments application. Results: The ΔE value did not differ significantly for the four groups at baseline measurement before treatment (p> 0.05). Icon resin infiltrant improved the color of WSLs significantly immediately after its application, giving the lowest ΔE value (3.00 ± 0.59), when compared to other treatments (p< 0.001). There were no significant changes in ΔE (p> 0.05) for all groups during the follow up intervals (one month, three and six months after treatments application). Conclusion: Resin infiltrant can improve the color of WSLs and restore the natural appearance of enamel better than nano-HA toothpaste and microabrasion.

RESUMO Objetivo: avaliar qualitativamente e quantitativamente os efeitos nas mudanças e estabilidade da cor de lesões de mancha branca (LMBs), após tratamento com infiltração de resina, em comparação aos tratamentos com pasta de dentes com nanopartículas de hidroxiapatita (Nano-HA) e com microabrasão. Métodos: As LMBs foram criadas artificialmente em 60 superfícies de esmalte dentário de pré-molares humanos e aleatoriamente divididas em quatro grupos (n=15, cada): pasta de dentes Nano-HA, microabrasão (Opalusture), tratamento com infiltração de resina (Icon) e saliva artificial (grupo controle). A mudança de cor (ΔE) de cada espécime foi aferida com um espectrofotômetro odontológico (Vita Easyshade) em diferentes tempos: início do estudo, após a criação das LMBs, após a aplicação dos tratamentos, um mês, três meses e seis meses após a aplicação dos tratamentos. Resultados: Os valores de ΔE não diferiram significativamente entre os quatro grupos ao início do estudo (p > 0,05). A infiltração com resina Icon melhorou significativamente a coloração das LMBs imediatamente após a sua aplicação, com o menor valor de ΔE (3,00 ± 0,59), quando comparada às outras modalidades de tratamento (p < 0,001). Não houve mudanças significativas nos valores de ΔE (p > 0,05) em qualquer um dos grupos durante os intervalos de acompanhamento (um mês, três meses e seis meses após a aplicação do tratamento). Conclusão: A infiltração de resina é capaz de melhorar a coloração das LMBs e restaurar a aparência natural do esmalte de forma superior à pasta de dentes com Nano-HA e à microabrasão.

Resistance of resin-infiltrated enamel to surface changes in response to acidic challenge.

OBJECTIVE: To investigate the ability of resin infiltration to protect demineralized enamel against acidic challenge. MATERIALS AND METHODS: Forty-five extracted healthy premolars were selected for the study, each of which was sectioned vertically into 2 halves, giving 90 specimens. Specimens were then divided into three groups, where specimens of group A were not decalcified (control), while those of groups B and C were either subjected to decalcification only, or decalcification followed by Icon resin infiltration, respectively. Each group was further divided into three subgroups, according to the type of storage medium (water, Coca-Cola, or Redbull). Evaluation parameters included color difference and surface roughness. Scanning electron microscope was used to evaluate enamel surface topography. Statistical analysis was performed by ANOVA followed by least significant difference test. RESULTS: Although Coca-Cola caused the highest color change and surface roughness among the studied specimens, yet, the resin-infiltrated enamel was more resistant to surface changes than the nonresin infiltrated enamel, even under acid attack. CONCLUSION: Resin infiltration has the ability to provide and maintain protection to the demineralized enamel against acidic attack. CLINICAL SIGNIFICANCE: Resin infiltration may be considered as a promising solution to restore esthetic of demineralized enamel following orthodontic treatment and to protect it against acidic beverages.

Effect of nanotechnology in self-etch bonding systems on the shear bond strength of stainless steel orthodontic brackets.

OBJECTIVE: To evaluate the effect of silica dioxide (SiO2) nanofillers in different bonding systems on shear bond strength (SBS) and mode of failure of orthodontic brackets at two experimental times. METHODS: Ninety-six intact premolars were divided into four groups: A) Conventional acid-etch and primer Transbond XT; B) Transbond Plus self-etch primer; and two self-etch bonding systems reinforced with silica dioxide nanofiller at different concentrations: C) Futurabond DC at 1%; D) Optibond All-in-One at 7%. Each group was allocated into two subgroups (n = 12) according to experimental time (12 and 24 hours). SBS test was performed using a universal testing machine. ARI scores were determined under a stereomicroscope. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to determine the size and distribution of nanofillers. One-way ANOVA was used to compare SBS followed by the post-hoc Tukey test. The chi-square test was used to evaluate ARI scores. RESULTS: Mean SBS of Futurabond DC and Optibond All-in-One were significantly lower than conventional system, and there were no significant differences between means SBS obtained with all self-etch bonding systems used in the study. Lower ARI scores were found for Futurabond DC and Optibond All-in-One. There was no significant difference of SBS and ARI obtained at either time points for all bonding systems. Relative homogeneous distribution of the fillers was observed with the bonding systems. CONCLUSION: Two nanofilled systems revealed the lowest bond strengths, but still clinically acceptable and less adhesive was left on enamel. It is advisable not to load the brackets immediately to the maximum.

Effect of nanotechnology in self-etch bonding systems on the shear bond strength of stainless steel orthodontic brackets

ABSTRACT Objective: To evaluate the effect of silica dioxide (SiO2) nanofillers in different bonding systems on shear bond strength (SBS) and mode of failure of orthodontic brackets at two experimental times. Methods: Ninety-six intact premolars were divided into four groups: A) Conventional acid-etch and primer Transbond XT; B) Transbond Plus self-etch primer; and two self-etch bonding systems reinforced with silica dioxide nanofiller at different concentrations: C) Futurabond DC at 1%; D) Optibond All-in-One at 7%. Each group was allocated into two subgroups (n = 12) according to experimental time (12 and 24 hours). SBS test was performed using a universal testing machine. ARI scores were determined under a stereomicroscope. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to determine the size and distribution of nanofillers. One-way ANOVA was used to compare SBS followed by the post-hoc Tukey test. The chi-square test was used to evaluate ARI scores. Results: Mean SBS of Futurabond DC and Optibond All-in-One were significantly lower than conventional system, and there were no significant differences between means SBS obtained with all self-etch bonding systems used in the study. Lower ARI scores were found for Futurabond DC and Optibond All-in-One. There was no significant difference of SBS and ARI obtained at either time points for all bonding systems. Relative homogeneous distribution of the fillers was observed with the bonding systems. Conclusion: Two nanofilled systems revealed the lowest bond strengths, but still clinically acceptable and less adhesive was left on enamel. It is advisable not to load the brackets immediately to the maximum.

RESUMO Objetivo: avaliar o efeito das nanopartículas de dióxido de silício (SiO2), presentes em diferentes sistemas adesivos, na resistência ao cisalhamento da colagem (RAC) e no modo de fratura de braquetes ortodônticos avaliados em dois momentos. Métodos: noventa e seis pré-molares intactos foram divididos em quatro grupos: A) condicionador ácido convencional e primer Transbond XT; B) primer autocondicionador Transbond Plus; e dois sistemas adesivos autocondicionantes reforçados com nanopartículas de dióxido de silício em diferentes concentrações, C) DC Futurabond a 1%; D) Optibond All-In-One a 7%. Cada grupo foi dividido em dois subgrupos (n = 12), de acordo com o tempo para realização do teste (12 e 24 horas). O teste da RAC foi realizado em uma máquina universal de ensaios. Os resultados do índice de adesivo remanescente foram determinados com um estereomicroscópio. Para determinar o tamanho e a distribuição das nanopartículas, utilizou-se microscopia eletrônica de varredura (MEV) e microscopia eletrônica de transmissão (MET). O ANOVA a um critério foi usado para comparar a RAC, seguido pelo teste post-hoc de Tukey. O teste qui-quadrado foi usado para avaliar os índices de adesivo remanescente. Resultados: a RAC média do Futurabond DC e do Optibond All-In-One foi menor do que a do sistema convencional, de forma estatisticamente significativa; e não houve diferença estatisticamente significativa entre os níveis médios de RAC obtidos nos sistemas adesivos autocondicionantes avaliados nesse estudo. Os menores índices de adesivo remanescente foram observados com o Futurabond DC e o Optibond All-In-One. Não houve, entre os sistemas adesivos, diferença significativa na RAC e nos índices de adesivo remanescente obtidos nos dois tempos de aplicação. Foi observada uma distribuição relativamente homogênea das partículas nos sistemas adesivos. Conclusão: os dois sistemas com nanopartículas demonstraram menor RAC, mas ainda aceitável e com o menor índice de adesivo remanescente no esmalte. É, assim, aconselhável não submeter os braquetes à carga máxima logo após a colagem.

Efficacy of a new sealant to prevent white spot lesions during fixed orthodontic treatment : A 12-month, single-center, randomized controlled clinical trial.

BACKGROUND AND OBJECTIVE: White spot lesions (WSLs) are an undesirable side effect of fixed orthodontic appliance therapy and are reported to occur in 2-96 % of orthodontic patients. In this study, the efficacy of a new sealant to prevent WSLs during fixed orthodontic treatment was compared to a control group that did not receive sealant. PATIENTS AND METHODS: For this 2-arm parallel-group randomized trial, 50 subjects aged 12-18 years (mean age 14.57 ± 2.04 years) were recruited from the orthodontics department at Mansoura University, Egypt. Eligibility criteria were no restorations, no active WSLs or caries, and adequate oral hygiene. Subjects were randomized in a 1:1 ratio to one of the two arms prior to undergoing fixed orthodontic treatment, namely a single application of SeLECT Defense™ sealant during the bracketing appointment or no sealant (control arm). Instructions and dentifrices for local home fluoridation regimen were identical in both groups. Oral hygiene was assessed using the Approximal Plaque Index (API) at specified time intervals. Dental photographs were taken for blinded WSLs assessment; inter- and intra-operator error were also calculated. Categorical data were tested using the χ 2 test, and a logistic regression model was adopted to detect associations between decalcification (WSLs), sealant application, and oral hygiene status. RESULTS: Only excellent or good oral hygiene were independent prognostic factors for preventing severe WSLs (p = 0.035). No significant effect on caries incidence was observed for the sealant. CONCLUSIONS: In combination with adequate oral hygiene SeLECT Defense™ helps to reduced the frequency of WSLs. However, the sealat showed no significant effect as sole preventive strategy.

Evaluation of stresses developed in different bracket-cement-enamel systems using finite element analysis with in vitro bond strength tests.

BACKGROUND: The purpose of this study was to determine the bond strength of different orthodontic bracket materials (ceramic, stainless steel, and titanium) as well as stresses developed in bracket-cement-enamel systems using finite element (FE) analysis. METHODS: One hundred and thirty-five extracted human caries-free upper central incisors were divided into three groups (n = 45/group) according to the type of orthodontic bracket materials (stainless steel, ceramic, and titanium). Each group was further subdivided into three subgroups (n = 15/group) according to the bond strength test loading mode (shear short side, shear long side, and tensile). After debonding, the fractured specimen was examined, and the adhesive remnant index (ARI) was determined. FE analysis models analyzed the stress distribution within the cement and enamel. Bond strengths were analyzed using ANOVA and Tukey's test, and the ARI scores were analyzed using chi-square (χ2) test. RESULTS: Shear loading at the short side of the bracket resulted in the highest bond strength and lowest maximum principal stress both on cement and enamel compared with the other loading modes (P < 0.05). Ceramic brackets presented with higher bond strength and lower maximum principal stress than metallic brackets (P < 0.05). There was a significant difference for ARI scores between the type of brackets (χ2 = 64.852, P < 0.001). CONCLUSION: The findings suggest that the manner of loading orthodontic brackets and the selection of orthodontic bracket materials affect the bond strength and stresses developed both on cement and enamel.

Effects of cyclic loading on the shear bond strength of metal orthodontic brackets bonded to resin composite veneer surface using different conditioning protocols.

BACKGROUND: The aim of this research is to evaluate cyclic (CSBS) and static shear bond strengths (SSBS) of metal orthodontic brackets bonded to composite laminates using different conditioning protocols. METHODS: A total of 80 direct nanofilled composite laminate veneers were prepared on permanent incisors and divided into four equal groups according to different surface treatments. In group 1, diamond bur was used. In group 2, microetcher (50-µm alumina particles) was utilized. In group 3, 38% phosphoric acid treatment for 60 s was done. In group 4 (control group), metal brackets were bonded to the untreated veneer surfaces using no-mix adhesive resin. SSBS testing was carried out for ten specimens, while CSBS testing was done for another ten specimens from each group. The data were subjected to analysis of variance and Scheffe post hoc test. The chi-square test was used to determine significant differences in the adhesive remnant index scores among different groups. RESULTS: Statistically significant difference was only found between SSBS of brackets bonded when surface treatment was done using the diamond bur, microetcher, and the phosphoric acid at P<0.05. With regard to CSBS, the use of bur treatment and microetching achieved the highest values; however, there was no significant difference between these two groups. With phosphoric acid, surface treatment achieved the lowest CSBS value; there was no significant difference between this group and the control group. The SSBS was significantly higher than CSBS in all groups. CONCLUSIONS: Roughening composite laminate veneers with either diamond bur or microetcher could be used successfully as an alternative to provide higher bond strength than phosphoric acid surface treatment. Cyclic loading significantly decreased bond strength.

Microleakage under orthodontic bands cemented with nano-hydroxyapatite-modified glass ionomer.

OBJECTIVES: To estimate the in vivo effect of nano-hydroxyapatite (HA) modification of banding glass-ionomer cement on microleakage under orthodontic bands. MATERIALS AND METHODS: Eighty noncarious premolars scheduled for extraction in 20 orthodontic patients were randomly divided into four groups. Grouping was based on the ratio of nano-HA (0%, 5%, 10%, 15% by weight) added to the luting glass-ionomer cement (GIC) Ketac-Cem, which was used for cementation of prefabricated micro-etched orthodontic bands. Dye penetration method was used for microleakage evaluation at the cement-band and cement-enamel interfaces. Statistical evaluation was performed with a Kruskal-Wallis test and a Mann-Whitney U-test, and a Bonferroni-adjusted significance level was calculated. RESULTS: Bands cemented with conventional GIC showed the highest microleakage scores in comparison to those cemented with nano-HA-modified GIC. No significant difference was found between teeth banded with 10% and 15% modified GIC. CONCLUSIONS: Modification of the banding GIC with 15% nano-HA revealed a positive effect on reducing microleakage around orthodontic bands.

In vivo effects of two acidic soft drinks on shear bond strength of metal orthodontic brackets with and without resin infiltration treatment.

OBJECTIVES: To evaluate the in vivo effects of two acidic soft drinks (Coca-Cola and Sprite) on the shear bond strength of metal orthodontic brackets with and without resin infiltration treatment. In addition, the enamel surface was evaluated, after debonding, using a scanning electron microscope. MATERIALS AND METHODS: Sixty noncarious maxillary premolars, scheduled for extraction in 30 orthodontic patients, were used. Patients were randomly divided into two groups according to the soft drink tested (Coca-Cola or Sprite). In each group, application of resin infiltration (Icon. DMG, Hamburg, Germany) was done on one side only before bonding of brackets. Patients were told to rinse their mouth with their respective soft drink at room temperature for 5 minutes, three times a day for 3 months. Shear bond strength was tested with a universal testing machine. After shearing test, a scanning electron microscope was used to evaluate enamel erosion. Statistical analysis was performed by twoway analysis of variance followed by the least significant difference test. RESULTS: The Coca-Cola group without resin infiltration showed the lowest resistance to shearing forces. Scanning electron micrographs of both groups after resin application showed a significant improvement compared with results without resin use, as the enamel appeared smoother and less erosive. CONCLUSION: Pretreatment with the infiltrating resin has proved to result in a significant improvement in shear bond strength, regardless of the type of soft drink consumed.

Twelve-month bracket failure rate with amorphous calcium phosphate bonding system.

The aim of the study was to compare the survival rate of orthodontic brackets over a 12-month period using amorphous calcium phosphate (ACP) bonding system with a conventional adhesive (CA). In 30 patients with a mean age of 15 years 7 months, one operator bonded 138 brackets with a split-mouth design, using a resin-based CA and ACP-containing adhesive. The survival rate of the brackets was estimated by Kaplan-Meier analysis. Bracket survival distributions with respect to bonding procedure, dental arch, type of tooth (incisor, canine, and premolar), and patients' gender were compared using the log-rank test. The bond failure interface was determined using the Adhesive Remnant Index (ARI). The bond failure rates of the CA and ACP-containing adhesive were 2.67 and 3.8 per cent, respectively. There was no significant difference between the failure rates of ACP and CA-bonded systems (P > 0.05). Survival rates did not show significant differences between the upper and lower dental arches (P > 0.05). Lower survival rates were found for canine and premolar teeth than incisors (P < 0.05). Bond failure rates were higher for males than females (P < 0.05). There was a significant difference for ARI scores between the adhesive materials (P = 0.028); more of the ACP-based adhesive was left on the tooth at debond. ACP-containing adhesive can be effectively used to bond orthodontic brackets and can serve as a practicable alternative to the conventional bonding adhesives.

Treatment of developing Class II Division 1 malocclusion with Jumper Twin Block.

UNLABELLED: The objective of this study was to determine dental and skeletal effects of the jumper twin block appliance in the treatment of developing Class II, Division I malocclusion. METHODS: 15 girls aged 9 to 11 years old with class II division 1 and samephysical maturation status were included in the study over one year. Cephalometric data and study models were analyzed statistically with Paired t-test. RESULTS: The jumper twin block had skeletal and dental effects. Stimulation of forward mandibular growth, backward displacement of the maxilla, significant increase in the anterior and posterior facial height, retroclination of the upper incisors, proclination of the lower incisors and significant improvement of the overjet and overbite had been found. CONCLUSIONS: The jumper twin block appliance with gradual bite advancement was effective in treatment of developing Class II division 1 malocclusion.

Effect of resin infiltration on white spot lesions after debonding orthodontic brackets.

PURPOSE: To evaluate the effect of application of a resin infiltration material on masking the white spot lesions (WSLs) after bracket removal. METHODS: 18 patients participated in this study and were divided into two groups of nine patients each; by a visual score based on the extent of demineralization, according to the classification of the WSLs. Group 1: Visible WSLs without surface disruption and Group 2: WSLs showed a roughened surface but not requiring restoration. Three successive photographs were taken for every patient; immediately after bracket removal, 1 week after oral hygiene measures and after Icon material application. The JPEG images were imported into image analysis software (Image J version 1.33u for Windows XP, US National Institutes of Health) which presented the images into histograms of gray scale from (0 to 255). Initial and final images were compared for percentage of WSLs masking area. RESULTS: For both groups, a statistically significant difference at P<0.05 was obtained as follows; for WSLs in Group 1, the means at gray scale for the initial and the final photographs were 126.091 +/- 13.452 and 221.268 +/- 9.350 respectively and they revealed significance by Wilcoxon's signed rank test = 0.038, P<0.05. For WSLs in Group 2, the means at gray scale for the initial and the final photographs were 95.585 +/- 20.973 and 155.612 +/- 31.203 respectively and they revealed significance by Wilcoxon's signed rank test = 0.029, P<0.05.

The use of different analgesics in orthodontic tooth movements.

OBJECTIVE: To provide a semi-quantitative assessment of the effect of different analgesics (celecoxib, ketorolac, and paracetamol) on tooth movement and bone resorption using immunohistochemical staining of matrix metalloproteinase-13 (MMP-13). MATERIALS AND METHODS: Forty white male rats (12-weeks old; body weight: 230-250 g) were divided into four groups (10 rats each) and were given the treatment once a day for 2 consecutive months. Group A (control group) rats were given the reverse osmosis water; group B rats were given 10 mg/kg celecoxib; group C rats were given 3 mg/kg ketorolac; and group D rats were given 150 mg/kg paracetamol. A precalibrated closed Sentalloy coil spring was placed inside each rat mouth to deliver a constant force of 50 cN. The magnitude of tooth movement was measured intraorally. After 2 months, the rats were sacrificed, and the sections were mounted on L-polylysine-coated glass slides. Slides from each specimen were stained with hematoxylin and eosin, and others were stained with MMP-13. Data were analyzed with the one-way analysis of variance (ANOVA). RESULTS: Celecoxib, ketorolac, and paracetamol groups showed tooth movement of 1.81 ± 0.43 mm, 1.13 ± 0.28 mm, and 1.08 ± 0.27 mm, respectively. The mean number of MMP-13-positive osteoclasts was highest in celecoxib-treated group followed by the control group and was decreased in the ketorolac and paracetamol groups. Comparing all groups to the control revealed significant differences (P < .05). CONCLUSION: Administration of celecoxib did not reduce bone resorption or interfere with tooth movement in rats compared to other analgesics tested (ketorolac and paracetamol).

Mechanical properties and surface characterization of translucent composite wire following topical fluoride treatment.

OBJECTIVE: To determine the effects of a fluoride prophylactic agent on the mechanical properties and surface quality of a preformed round translucent composite archwire while comparing it with nickel-titanium (Ni-Ti) and multistranded stainless steel wires. MATERIALS AND METHODS: The wires were immersed in an acidulated phosphate fluoride solution (APF) or in distilled water (control) for 1.5 hours at 37°C. Flexural modulus of elasticity (E) and yield strength (YS) of the wires were measured using a three-point bending test in a universal testing machine. The springback ratio (YS/E) was calculated for each wire. The influence of fluoride treatment on properties of the wires was statistically analyzed using Student's t-test at α  =  .05. Surface changes were observed with a scanning electron microscope. RESULTS: Fluoride treatment produced a statistically significant reduction in E, YS, and YS/E of the composite wire (P < .05). In addition, a significant decrease in E of Ni-Ti wire was found after exposure to fluoride, upon comparison with distilled water control treatment. On the other hand, no significant effect of fluoride treatment was found on YS and YS/E of Ni-Ti wire and on studied properties of the multistranded stainless steel wire (P > .05). Corrosive changes in surface topography were observed after exposure to the fluoride agent and were more pronounced with the composite wire. CONCLUSIONS: These results suggest that using a topical fluoride agent with translucent composite wire could decrease the mechanical properties and might damage the surface of the wire, potentially contributing to prolonged orthodontic treatment.

Intrusion of maxillary incisors by mini-screw anchorage of Angle Class II division 2 malocclusion cases.

OBJECTIVES: to evaluate the effects of the upper incisor teeth intrusion by mini-screw on the amount of overbite and on the dental and skeletal parameters of the jaws. MATERIAL AND METHODS: Ten patients were selected from the outpatient clinic of the Department of Orthodontics, Faculty of Dentistry, Mansoura University with Angle's Class II division 2 malocclusions. Ages ranged from 13 to 19 years with deep overbite of 4mm or more requiring intrusion of the maxillary incisors. Alignment of the upper and lower dental arches was done with a pre-adjusted edgewise technique, then a mini-screw as anchorage for the intrusion of the upper incisor segment was inserted for every patient below the anterior nasal spine connected to a utility arch wire. RESULTS: The overbite was corrected from 6 mm to 1.8 mm (p<.001) by upper incisor intrusion and the gummy smile was improved. No extrusion of upper first permanent molars was observed. CONCLUSIONS: The maxillary incisors were effectively intruded by using mini-screws as orthodontic anchorage. Good occlusion and facial esthetics were achieved with no counteractive movements in the molars.

Study of the effect of different surface treatments and surface roughness of veneered crowns on shear bond strength of ceramic brackets.

The orthodontist is often faced with the problem of bonding brackets to ceramic restorations. The purpose of this study was to find the most reliable method for bonding ceramic brackets onto ceramic crowns.

Dental age estimation in Egyptian children, comparison between two methods.

The need to estimate age of living individuals is becoming increasingly more important in both forensic science and clinical dentistry. The study of the morphological parameters of teeth on dental radiographs of adult humans is more reliable than most other methods for age estimation. Willems and Cameriere methods are newly presented methods. The aim of this work was to evaluate the applicability of using these methods for Egyptian children. Digitalized panoramas taken from 286 Egyptian children (134 boys, 152 girls) with age range from 5 to 16 years were analyzed. The seven left permanent mandibular teeth were evaluated using the two methods. The results of this research showed that dental age estimated by both methods was significantly correlated to real age. However, Willems method was slightly more accurate (98.62%) compared to Cameriere method (98.02%). Therefore, both methods can be recommended for practical application in clinical dentistry and forensic procedures on the Egyptian population.