Assessing AudaxCeph®'s cephalometric tracing technology versus a semi-automated approach for analyzing severe Class II and Class III skeletons.

OBJECTIVE: To evaluate the accuracy and precision of the AudaxCeph® fully automated software in identifying cephalometric landmarks on lateral cephalograms of Class II and Class III skeletal relationships, comparing its performance against experienced orthodontists using manual tracing within the same software environment. MATERIAL AND METHODS: Sixty cephalograms depicting severe Class II or Class III skeletal discrepancies were assessed by two board-certified orthodontists and AudaxCeph®'s artificial intelligence automatic tracing software. Among these, 40 cases were classified as Class II and 20 as Class III. An X-Y axis was established at the bottom left corner of each cephalogram, and subsequent X and Y coordinates for the landmarks were exported to Excel. Thirteen cephalometric landmarks were identified and used for comparing manual and automatic tracing methods, with no alteration of landmark positions post-tracing. Measures of the X coordinate, Y coordinate, and radial distance for each landmark were compared using t-tests for equivalence with a 2mm margin, both against AudaxCeph®'s positions and intra-operator reliability. RESULTS: Analysis revealed that while most operator measurements closely approximated AudaxCeph® values, discrepancies exceeding 2mm were notable at Gonion and Porion landmarks. Slight variability was noted in one instance during intra-examiner evaluation at the Gonion landmark. CONCLUSIONS: This study concludes that AudaxCeph®'s artificial intelligence-driven automatic tracing of cephalograms offers a reliable and accurate method for orthodontic treatment planning across various skeletal types and severities. On average, it exhibits minimal discrepancies exceeding 2mm compared to manual operators, with notable variations observed primarily at the Gonion and Porion landmarks. While AudaxCeph® is an acceptable tool for cephalometric landmark location, it's accuracy still require the practitioner to verify some less reliable landmark locations.

Shear bond strength of orthodontic brackets to single-shade composite surfaces: An in-vitro comparative study of different surface preparations.

PURPOSE: The primary objective of this study was to determine which single-shade composite surface yielded clinically acceptable shear bond strength (SBS) to metal orthodontics brackets. The secondary objectives were to identify the best composite surface treatment to enhance SBS and determine which surface treatment produced the least surface damage at debond. METHODS: Forty dental composite samples were selected from four different manufacturers (n=160) and grouped by manufacturer, one standard multi-shade dental system (FilTek™ Supreme Ultra) and three single-shade dental composites systems (OmniChroma®, SimpliShade™ and Venus® Diamond One). Each group of forty samples was randomly divided into four sub-groups (n=10). Each sub-group was identified by the surface treatment used, hydrofluoric acid (HFA), micro-etching (MIC), or phosphoric acid (PA). Shear bond strength testing and adhesive remnant index (ARI) were performed. Statistical analyses included Kruskal-Wallis, Wilcoxon rank-sum, and two-factorial ANOVA. RESULTS: OmniChroma® had statistically significant lower shear bond strength than the other composite materials tested. The control groups had statistically significant lower shear bond strength than Group 1/HFA (P<0.001) and Group 2/MIC (P<0.001). Group 1/HFA had the lowest distribution ARI score overall, while MIC had the highest ARI score distributions. CONCLUSIONS: The results of this in-vitro study found that all tested composite materials achieved clinically acceptable shear bond strengths. The utilization of micro-etching produced higher SBS. Significant Adhesive Remnant Index scores (< 0.001) were only found for OmniChroma® without any surface preparation.

Shear bond strength of orthodontic brackets bonded to high-translucent dental zirconia with different surface treatments: An in vitro study.

PURPOSE: The objective of this study was to compare the shear bond strengths of orthodontic brackets bonded to translucent dental zirconia samples which are anatomically accurate and treated with various surface treatments. METHODS: This in vitro study included 156 samples from 3 brands of high-translucent zirconia split into a control group and 4 surface treatment groups: 9.6% hydrofluoric acid etching, 50-micron aluminium oxide particle air abrasion, and 30-micron tribochemical silica coating (TBS) particle air abrasion with and without silane application. After surface treatment, all groups were primed with a 10-MDP primer and bonded to metal orthodontic brackets. Shear bond strength (SBS) was tested and results were compared between all groups. Data analysis consisted of a balanced two-factor factorial ANOVA, a Shapiro-Wilks test, and a non-parametric permutation test. The significance level was set at 0.05. RESULTS: Among all surface treatments, aluminium oxide particle abrasion produced significantly higher SBS (P≤0.002). Lava™ Plus zirconia samples had significantly higher SBS than Cercon® samples (P<0.0001). TBS surface treatment produced significantly higher SBS on Lava™ Plus samples than it did on the other zirconia brands (P=0.032). CONCLUSIONS: This study indicated that mechanical abrasion using aluminium oxide in combination with a 10-MDP primer creates a higher SBS to high-translucent zirconia than the bond created by tribochemical silica coating. Also, there was no significant difference in ARI regardless of zirconia brand or surface preparation.

An overview of current evaluation methods of postgraduate dental specialty residents.

PURPOSE: A lack of contemporary dental literature exists on evaluating dental residents in postgraduate education, with no standardized criteria or information on technology adoption. This study aims to understand current evaluation methods in dental residency programs and compare them to existing literature. METHODS: A survey with 22 questions was sent to program directors of 749 ADA/CODA (American Dental Association/Commission on Dental Accreditation)-accredited postgraduate dental residencies. The questions focused on evaluation frequency, faculty involvement, submission methods, and electronic software usage. RESULTS: The survey response rate was 30.2% (226 responses). Results show that 98% of program directors are involved in evaluations, but require more support from auxiliary faculty. Evaluations are typically submitted twice or four times a year, with 12% of programs wanting increased frequency. Face-to-face delivery of feedback is considered crucial. While desktop computers are widely used for evaluation submission, 55% of programs utilize mobile devices, which correlates with higher program director satisfaction. The most popular evaluation software includes New Innovations, MEd Hub, and Qualtrics. Overall, 86.96% of program directors are satisfied with current evaluation practices. Areas needing improvement are non-program director faculty involvement, resident response/feedback, and software navigation. CONCLUSION: This study found that a majority of program directors of the postgraduate dental education system are using electronic technology for their resident evaluation systems and are satisfied with their current mechanism of evaluation.

A survey of white spot lesion prevention and resolution in the US dental school curricula.

PURPOSE/OBJECTIVES: White spot lesions (WSLs) are opaque white lesions on smooth tooth surfaces as a result of demineralization. Proven methods of prevention and resolution of these lesions are available yet the incidence rate, especially in orthodontic patients, is still high. Perhaps the way dental schools are educating students on the topic is insufficient. The purpose of this study was to determine if and how predoctoral dental students are taught about the prevention and resolution of WSLs. METHODS: An electronic survey was developed and sent out to each of the 66 accredited dental schools in the United States and Puerto Rico. The survey consisted of 13 questions and inquired about whether the school includes instruction of WSLs in its predoctoral curriculum. If the school indicated instruction WSLs was in the predoctoral curriculum, further questions were asked pertaining to the content and method of the instruction. Demographic data was also gathered from each institution. RESULTS: Twenty-eight of the 66 schools responded for a 42% response rate. Eighty-two percent of schools indicated they were teaching about prevention of WSLs, while 50% indicated they were teaching about resolution, or treatment, of WSLs. The most commonly taught methods were patient education, over-the-counter fluoride mouthrinse, toothpaste, or gel, and high fluoride content toothpaste. CONCLUSION: The majority of responding dental schools are at least including some instruction of WSLs in the predoctoral curriculum. Many of the known prevention and treatment measures available, however, are not routinely taught.

Shear bond strength of adhesive precoated brackets: A comparative in vitro study.

OBJECTIVE: This study compared the shear bond strength of orthodontic precoated brackets from different manufacturers. METHODS: Sixty extracted human premolar teeth were divided into six groups (n=10). The groups were bonded with one of the following brackets: 3M™ Unitek Victory™ Series™ with APC, 3M™ Unitek Clarity™ Advanced Ceramic™ with APC, TP Nu-Edge® NX Cobalt-Chromium and TP In-Vu® ceramic Readi-Base® both with eXact® orthodontic adhesive, 3M™ Unitek Clarity Advanced Ceramic™ and 3M™ Unitek Victory™ Series™ both with Transbond™ XT Adhesive. Each group was tested for shear bond strength using a universal testing machine. Each sample was observed under a dissecting microscope and received an adhesive remnant index (ARI) score. Statistical analysis was performed using Tukey's Standardized Range (HSD) Test to make comparisons among all groups and a Wilcoxon rank-sum test to evaluate for pairwise comparisons between the groups. The P-values<0.05 were considered significant. RESULTS: The ceramic control was not statistically different from the metal control, 3M™ Victory™ APC™, TP In-Vu® ceramic eXact® or TP Nu-EDGE® eXact® in terms of shear bond strength (7.69±1.41MPa, 7.72±1.25MPa, 8.70±1.93MPa, 4.90±1.76MPa, 5.33±0.78MPa, respectively). However, it was statistically different from 3M™ Ceramic APC™ (10.29±2.78MPa). In terms of modulus, there were no statistical differences. TP's Nu-edge® had the lowest average ARI score, but was not statistically different when compared to the other groups. CONCLUSION: 3M™ Unitek's Ceramic APC had a statistically higher SBS than the non-precoated brackets and TP Orthodontics' precoated brackets. However, all SBS were 4.9 MPA or above, which is deemed clinically acceptable in terms of laboratory forces. There was no statistical difference between manufacturing companies or precoated vs. non-precoated modulus and ARI scores.

The prevalence of developmental dental and eruption anomalies assessed using panoramic radiographs: a retrospective study.

Developmental dental anomalies are a common finding in adolescent populations. The objective of this study was to utilize panoramic radiographs to determine the prevalence of dental anomalies and developmental disturbances in a heterogenous adolescent orthodontic patient population seeking care at a North American orthodontic residency program. A total of 1042 panoramic radiographs of 457 male and 585 female orthodontic patients aged 10 to 18 years were evaluated. Developmental and eruption anomalies were recorded and categorized, and chi-square and Fisher exact tests were used for statistical analysis. The evaluation revealed that 40.88% of patients had at least 1 anomalous finding. The most common finding overall was agenesis (12.00%), followed by deviations in eruption path (9.12%), delayed eruption (7.39%), and impaction (7.29%). There was no difference in the prevalence of having any anomalous finding or the prevalence of any specific category of anomalies based on the sex or Angle classification of the patients. Comparison of developmental dental anomalies in 3 age groups (10 to 12, 13 to 15, or 16 to 18 years) revealed no statistically significant difference in the overall prevalence of anomalous findings. Statistically significant differences for some specific categories of anomalies were explainable by correlating dental development with chronologic age, such as a greater frequency of blocked out teeth and eruption path deviation among patients aged 10 to 12 years. Black patients were found to have a significantly greater prevalence of impactions (P = 0.030), and Asian patients had a significantly greater prevalence of anomalies categorized as "other pathology," which could not be definitively diagnosed by panoramic radiograph alone (P = 0.007).

Formulation and characterization of experimental orthodontic adhesive containing antibacterial dimethacrylate DABCO monomers: An in vitro study.

OBJECTIVE: The purpose of the study was to investigate the antibacterial efficacy and mechanical properties of experimental orthodontic adhesives containing newly synthesized antibacterial dimethacrylate monomers with doubly charged 1,4-diazabicyclo[2.2.2]octane (DABCO) group (dication). METHODS: Experimental orthodontic adhesives were formulated using varying compositions of synthesized antibacterial dimethacrylate monomers containing DABCO dication, C16DC2DMA and BisC11DCDMA, replacing part of the control group, Transbond™XT. The concentrations of monomers tested were 5% C16DC2DMA, 10% C16DC2DMA, 5% BisC11DCDMA, and 10% BisC11DCDMA. The biofilm-inhibition effects of the experimental adhesives against Streptococcus mutans were tested. Brackets were then bonded to extracted human teeth utilizing the experimental adhesives in the bonding protocol. The shear bond strength and modulus of elasticity of the control and experimental groups were tested. The adhesive remnant index scores were recorded. RESULTS: The experimental adhesives containing 5% or 10% BisC11DCDMA and 10% C16DC2DMA showed significantly lower S. mutans colony forming units (CFU) than the control. Both BisC11DCDMA experimental groups displayed similar mechanical properties as compared to the control, although 10% C16DC2DMA showed a reduction in shear bond strength as compared to the control. For all experimental adhesives, the adhesive remnant index scores were not significantly different compared to the control. CONCLUSION: BisC11DCDMA is a novel antibacterial dimethacrylate monomer that exhibits the significant ability to inhibit bacterial growth while maintaining acceptable mechanical properties. When incorporated into orthodontic adhesives, this monomer may reduce the occurrence of white spot lesions around brackets in orthodontic patients.

Comparison of AudaxCeph®'s fully automated cephalometric tracing technology to a semi-automated approach by human examiners.

OBJECTIVE: To compare the reliability of cephalometric landmark identification by an automated tracing software based on convolutional neural networks to human tracers. MATERIALS AND METHODS: Sixty cephalograms were traced by two board-certified orthodontists and AudaxCeph®'s artificial intelligence software. The following thirteen landmarks were identified in each tracing: Sella, Nasion, A point, B point, Porion, Menton, Pogonion, Orbitale, Gonion, Upper Central Incisor Incisal Edge (U1 Tip), Upper Central Incisor Root Apex (U1 apex), Lower Central Incisor Incisal Edge (L1 Tip), Lower Central Incisor Root Apex (L1 apex). An x-y axis was positioned in the bottom left corner of each cephalogram, and the x- and y-coordinates for the landmarks were exported into Excel. Distributions of landmarks (X, Y, radial distance) were compared using t-tests of equivalence with a 2mm equivalence bound. These compared the AI position to the two orthodontists - and the orthodontists' reliability by comparing equivalence against each other. RESULTS: There was no statistical difference between the orthodontists and AudaxCeph®'s automatic tracing software except for the x- and y-dimension of Porion and the y-dimension of L1 apex. The two orthodontists had good intra-examiner reliability with no statistical difference found when comparing them. CONCLUSION: AudaxCeph®'s automated cephalometric tracing software is a good adjunctive tool to use when diagnosing and treatment planning orthodontic cases.

Quantifying the degree of white spot lesions on enamel caused by different commercial beverages using the Canary Caries Detection System: An in vitro study.

Background. The use of sports and energy drinks has drastically increased in the adolescent population. This population often is in orthodontic treatment, and the use of such drinks with poor oral hygiene promotes the development of white spot lesions (WSLs). Quantifying the degree of the lesion has been limited in the past. The hypothesis was that the Canary Caries Detection System could be used to quantify the degree of WSLs caused by different commercial beverages. Methods. A total of 105 extracted human premolars were divided into seven groups (n=15). Each group was tested in one of six beverages or a phosphate-buffered solution (control). The teeth were exposed to its beverage three times a day for 15 minutes for 28 days. Canary numbers and ambient light and fluorescent photographs were collected at baseline (T0 ) and on days 14 (T1 ) and 28 (T2 ). Results. The paired t test and one-way ANOVA found that T0 to T1 measurements were statistically significant (P<0.0015) and that T0 to T2 measurements were statistically significant (P<0.0001). Visually, the ambient light photographs and fluorescent photographs from T0 to T1 and T1 to T2 correlated with the increase in Canary numbers. Conclusion. This in vitro study revealed a statistically significant increase in the T0 to T1 Canary numbers and a statistically significant increase from T0 to T2 Canary numbers for all the test beverages. Changes in Canary numbers indicated significant changes in mineral density (i.e., demineralization) and development of WSLs on enamel after exposure to sports and energy beverages.

Comparison of Tie Wing Fracture Resistance of Differing Ceramic Brackets.

OBJECTIVE: The aim of this study was to compare the tie wing fracture resistance of 4 different manufacturers' ceramic brackets currently on the market. METHODS: The tie wings of ceramic brackets from 4 manufacturers were tested with 10 samples in each group. The brackets were Ormco Symetri, 3M Clarity, American Radiance Plus, and Dentsply Ovation S. The brackets were mounted and fixed in a universal testing machine. A stainless steel ligature wire was looped around a tie wing and the mean tensile strength was both tested and recorded. RESULTS: There was a significant overall difference in tensile strength among the 4 groups (P < .0001) with the 3M Clarity brackets having the highest MPa. When the groups were compared to each other, they also showed a significant difference in mean tensile strength with the exception being the American Radiance Plus and Ormco Symetri brackets. CONCLUSION: Test results concluded that the 3M Clarity brackets had the highest resistance to tie wing fracture, while the Dentsply Ovation S brackets had the lowest resistance.

A comparison of traditional orthodontic polishing systems with composite polishing systems following orthodontic debonding.

INTRODUCTION: At the completion of treatment, the orthodontic practitioner's goal is to effectively remove all traces of adhesive and return enamel to its initial state. With the advent of new polishing systems being released each year, there may be one product that is superior to others. AIM: The purpose of this study is to determine the efficacy of new polishing systems (in the last 5-10 years) used in general dentistry on enamel surface roughness following debond utilizing profilometery and scanning electron microscopy and compare them to established orthodontic polishing systems results. METHODS: Fifty-two mandibular incisors were randomly assigned to one of five test groups (N = 10) and two incisors (untreated enamel) were used for profilometer and scanning electron microscopy analysis at the end of testing. After bracket removal, the teeth were polished using traditional polishing products (Komet H48L bur, Reliance 'Renew' point) and newer polishing products (Coltene Spiral Composite Plus Polisher, Ultradent Jiffy Composite Polishing Spiral or 3M Sof-Lex™ Diamond Polishing System). The results were evaluated using a profilometer and scanning electron microscopy images. RESULTS: The results of a one-way analysis of variance (ANOVA) determined that the mean change in enamel surface roughness was not statistically different both in the traditional and novel groups. Tukey's Honestly Significant Difference (HSD) test found that there was no statistically significant difference in the change in enamel surface roughness between instrument groups. CONCLUSIONS: There was no statistically significant difference in enamel surface roughness after polishing between traditional orthodontic polishing systems and the selected novel polishing systems. SEM analysis revealed similar findings. This supports previous research suggesting that a wide variety of polishing systems or none at all, may be used to restore enamel smoothness after removal of orthodontic appliances.

Nickel and chromium ion release from coated and uncoated orthodontic archwires under different pH levels and exposure times.

OBJECTIVES: The purpose of this study was to determine and compare nickel and chromium ion release from traditional stainless steel and nickel titanium wires and newer esthetic archwires under different pH conditions, for different time intervals. METHODS: Ten pieces of 10-mm segments of five different orthodontic archwires were submerged in buffer solutions of pH 4.0, 5.5, and 7.0, for 4 and 13 weeks. The sample solutions were analyzed using ICP-MS. First, the results were analyzed by three-way ANOVA to determine any significant differences in metal concentration (ppb) between the different groups. Then, a post-hoc multiple pairwise comparison by Tukey's Studentized Range (HSD) Test was conducted to further compare the different materials and pH conditions. RESULTS: For nickel, uncoated NiTi had the highest nickel ion release (ppb), while AO Iconix had the lowest average nickel ion release, with a significant difference (p < 0.0001). The average nickel release increased with time and decreased with pH. For chromium, materials with uncoated stainless steel had the highest average chromium ion release, whereas AO Iconix had the lowest average chromium ion release, with a statistically significant difference (p < 0.0001). Chromium ion release increased with time and decreased with pH. CONCLUSIONS: There were significant differences in metal ion release between different pH conditions, materials, and time points. The metal ion release increased with increase in time and decrease in pH. Overall, the coated archwires showed less metal ion release than the uncoated wires.

Prevalence of Molar-Incisor Hypomineralization Within an Orthodontic Department in the United States.

Purpose: The purpose of this study was to determine the prevalence and severity of molar-incisor hypomineralization (MIH) by examining standard orthodontic intraoral photographs. Methods: A total of 690 patients were evaluated retrospectively for the presence or absence and extent of MIH using standardized assessment criteria. Results: Fourteen percent of all patients examined presented with MIH on at least one tooth. There was no significant difference in the presence of MIH when compared to age, race, or gender. MIH is most commonly presented on maxillary molars and maxillary central incisors as demarcated opacities with less than one-third of the tooth affected. More severe clinical status groups were associated with higher average age and were more commonly seen in molars than incisors. Conclusions: At 14 percent, the prevalence is reflective of the worldwide prevalence previously determined from other studies. MIH most commonly presents in its mildest form; however, older individuals tend to present with more severe forms, indicating that it continues to cause problems as patients age. Future studies should extend to further areas to continue to ascertain the extent and severity of this condition.

Comparison of tensile bond strength of new and rebonded Symetri Clear™ ceramic brackets with Transbond™ XT or BluGloo™, with or without surface treatment: An in vitro study.

OBJECTIVES: This study sought to determine the bond strength of the Symetri Clear™ bracket after rebonding (reused) for a second and third time. MATERIALS AND METHODS: Symetri Clear™ mandibular incisor brackets were bonded to bovine incisors and divided into six experimental groups. Two groups underwent tensile bond strength testing, and the remaining four groups were debonded using the manufacturer's recommended plier. Two groups were rebonded twice following surface preparation with Ortho SoloTM and two groups were rebonded twice without surface preparation. The rebonded brackets also underwent tensile bond strength testing after each rebonding event as well as receiving an Adhesive Remnant Index score. RESULTS: One-way ANOVA found a statistically significant difference in bond strength among the six groups (P<0.0001). Tukey's Studentized Range (HSD, honestly significant difference) Test found significant differences in tensile bond strength of groups which did not undergo surface preparation prior to rebonding. One-way ANOVA found a P-value of 0.2563 and thus no significant difference in ARI among the different groups. CONCLUSIONS: There was no significant difference in the tensile bond strength of Symetri ClearTM brackets initially bonded with either Transbond™ XT or BluGloo™ and no significant difference between the initial tensile bond strength and the first or second rebond tensile bond strength. Rebonding Symetri Clear™ brackets without surface treatment did show significantly reduced tensile bond strength.

In vitro comparison of shear bond strengths of ceramic orthodontic brackets with ceramic crowns using an aluminium oxide air abrasion etchant.

OBJECTIVE: The aim of this study was to determine if there are differences between the shear bond strengths of 3 types of ceramic brackets when bonded to different ceramic substrates using an aluminium oxide air abrasion etchant protocol. MATERIALS AND METHODS: Substrate groups consisting of thirty-six lithium disilicate (e.max® CAD) samples and thirty-six lithium silicate infused with zirconia (CELTRA® DUO) samples were fabricated to replicate the facial surface of a left maxillary central incisor. The surface of all samples was prepared with an aluminium oxide air abrasion etchant protocol. Each substrate group was split into three test groups (n=12). Each test group was bonded using a different brand of ceramic orthodontic bracket. Shear bond strength (SBS) testing was conducted and the mean SBS values for each group were calculated and recorded in MPa. An Adhesive Resin Index (ARI) score was also assigned to each sample to assess the location of bond failure. RESULTS: Mean SBS of the e.max® CAD groups were significantly less than the CELTRA® DUO groups. Symetri brackets showed significantly higher shear bond strengths to both substrates than both of the other brackets tested. ARI scores of the e.max® CAD groups were significantly less than the CELTRA® DUO groups. CONCLUSION: The Symetri bracket was the only bracket that was effective for both substrates (mean SBS>6mPa). The Etch Master protocol does not appear effective for e.max® CAD.

Formulation and characterization of antibacterial orthodontic adhesive.

OBJECTIVE: The objective of this study was to formulate experimental orthodontic bracket adhesives and test their mechanical properties, fluoride release and antibacterial activity. METHODS: Four experimental antibacterial orthodontic bracket adhesives were prepared with different compositions of synthesized antibacterial monomers replacing total 5% of dental monomers in the control Transbond XT (3M): 5%C11, 3.5%C11+1.5%C2, 5%C16, and 3.5%C16+1.5%C2. Transbond XT alone was used as control. These groups were used to bond premolar brackets to extracted premolars. Shear bond strength (SBS) was tested using an Instron machine. For antibacterial test, disk specimens (10mm diameter, 1mm thick, n=4) were fabricated and incubated with cultures of cariogenic Streptococcus mutans for 48h, and following gentle sonication, S. mutans biofilms in colony-forming-units (CFU) on the disks were enumerated by plating on agar medium. The data were analyzed using ANOVA and Tukey test (α=0.05). RESULTS: All experimental groups had similar shear bond strength (no significant difference) to the control. All experimental groups showed significant inhibitory effect against S. mutans biofilm formation, when compared to the control, but there was no significant difference between experimental groups. CONCLUSION: Antibacterial orthodontic adhesive can be fabricated to have similar mechanical properties but better caries-inhibitory effect than current adhesive.

Shear bond strength of orthodontic brackets bonded to a new all-ceramic crown composed of lithium silicate infused with zirconia: An in vitro comparative study.

AIM: This study sought to determine whether a clinically acceptable shear bond strength (SBS) of metal orthodontic brackets is achievable to CAD/CAM (Computer-Aided Design/Manufacturing) lithium silicate infused with zirconia and whether a chemical pre-treatment bonding protocol produced a higher shear bond strength. MATERIALS AND METHODS: Twenty lithium silicate infused with zirconia (CELTRA® DUO) samples, twenty zirconia samples, and twenty lithium disilicate samples were fabricated to replicate the facial surface of a mandibular left first molar. The samples were split into two test groups, one of which received a chemical pre-treatment protocol (hydrofluoric acid etch). Shear bond strength testing was conducted and the mean, maximum, minimal, and standard deviation SBS values for each were calculated and recorded in MPa. An Adhesive Resin Index (ARI) score was also assigned to each sample to assess the mode of bond failure. RESULTS: SBS of the lithium silicate infused with zirconia groups were significantly less than the chemically pre-treated lithium disilicate group, however both materials, when chemical pre-treatment protocol was used, were not statistically different than the enamel control. CONCLUSIONS: Orthodontic bonding to lithium silicate infused with zirconia yielded a weaker shear bond strength than bonding to traditional lithium disilicate, however, when the surface was pre-treated with hydrofluoric acid etch it provides a bond strength that is within an acceptable clinical range.

Formulation and characterization of antibacterial orthodontic adhesive

ABSTRACT Objective: The objective of this study was to formulate experimental orthodontic bracket adhesives and test their mechanical properties, fluoride release and antibacterial activity. Methods: Four experimental antibacterial orthodontic bracket adhesives were prepared with different compositions of synthesized antibacterial monomers replacing total 5% of dental monomers in the control Transbond XT (3M): 5%C11, 3.5%C11+1.5%C2, 5%C16, and 3.5%C16+1.5%C2. Transbond XT alone was used as control. These groups were used to bond premolar brackets to extracted premolars. Shear bond strength (SBS) was tested using an Instron machine. For antibacterial test, disk specimens (10mm diameter, 1mm thick, n=4) were fabricated and incubated with cultures of cariogenic Streptococcus mutans for 48h, and following gentle sonication, S. mutans biofilms in colony-forming-units (CFU) on the disks were enumerated by plating on agar medium. The data were analyzed using ANOVA and Tukey test (α=0.05). Results: All experimental groups had similar shear bond strength (no significant difference) to the control. All experimental groups showed significant inhibitory effect against S. mutans biofilm formation, when compared to the control, but there was no significant difference between experimental groups. Conclusion: Antibacterial orthodontic adhesive can be fabricated to have similar mechanical properties but better caries-inhibitory effect than current adhesive.

RESUMO Objetivo: o objetivo do presente estudo foi formular, experimentalmente, adesivos para colagem de braquetes ortodônticos e testar as suas propriedades mecânicas, sua liberação de flúor e sua atividade antibacteriana. Métodos: quatro adesivos ortodônticos antibacterianos foram preparados experimentalmente usando monômeros sintéticos antibacterianos com diferentes composições, substituindo-se 5% do monômero do grupo controle (Transbond XT, 3M) por: 5%C11; 3,5%C11 + 1,5%C2; 5%C16; ou 3,5%C16 + 1,5%C2. O Transbond XT original foi utilizado como controle. Esses diferentes adesivos foram usados para colar braquetes de pré-molares em pré-molares extraídos. A resistência da colagem ao cisalhamento (RCC) foi testada utilizando-se uma máquina Instron. Para os testes antibacterianos, amostras em formato de disco (10 mm de diâmetro, 1 mm de espessura, n = 4) foram fabricadas e incubadas por 48 horas com culturas cariogênicas de Streptococcus mutans. Após leve sonicação, os discos contendo os biofilmes de S. mutans em unidades formadoras de colônia (UFC) foram colocados em placas com meio de cultura ágar e numerados. Os dados foram analisados utilizando-se ANOVA e teste de Tukey (α?#8197;= 0,05). Resultados: todos os grupos experimentais apresentaram RCC semelhante (sem diferença significativa) ao grupo controle. Todos os grupos experimentais apresentaram significativo efeito inibitório contra a formação do biofilme de S. mutans, em comparação ao grupo controle, porém sem diferença significativa entre os grupos experimentais. Conclusão: adesivos ortodônticos antibacterianos podem ser produzidos para alcançar propriedades mecânicas semelhantes às dos adesivos atuais, porém com melhores efeitos inibitórios de cáries.

Effectiveness of Vanish XT in Reducing the Development of White Spot Lesions: An In Vitro Study.

PURPOSE: To evaluate the effectiveness of Vanish XT in preventing white spot lesions (WSLs) when placed around orthodontic brackets. The efficacy of Vanish XT was compared with that of Pro Seal, a commercially available product already proven in preventing demineralization. MATERIALS AND METHODS: Sixty extracted human canine teeth were divided into three groups (n = 20). The two experimental groups were treated with either Vanish XT or Pro Seal. A third group received no treatment (control). Ethidium bromide with DNA was added to and mixed with the products to produce fluorescence to verify retention of the experimental products. The teeth were submersed in a lactic acid solution for 32 days to create WSLs. All sample teeth were brushed twice daily with a non-fluoride toothpaste to evaluate retention of the experimental products. Photos were taken under fluorescence microscopy and white light at three time intervals. Demineralization was quantified utilizing computer software, and photos were analyzed to obtain values for percent surface area of demineralization and surface color change. RESULTS: Percent surface area of WSL data, both under white light conditions and fluorometric analysis, revealed a significant difference between Pro Seal and Vanish XT when compared with the control group. No significant differences were found between Pro Seal and Vanish XT treated teeth. Fluorescence evaluation revealed that both experimental products were largely removed by 32 days of brushing and acid exposure. CONCLUSION: Vanish XT is effective in preventing demineralization around orthodontic brackets. Its preventive efficacy is equivalent to that of Pro Seal.