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White spot lesions (WSLs) or decalcifications remain a common complication in orthodontic patients with poor oral hygiene. The purpose of this study was to compare attitudes regarding the development of WSLs among patients, parents, orthodontists and general dentists and improve prevention and treatment protocols through better communication. A survey was developed to evaluate and compare the current opinions of orthodontic patients (n=315), parents (n=279), orthodontists (n=305) and general dentists (n=191) regarding the significance, prevention and treatment of WSLs. All four groups indicated that WSLs did detract from the overall appearance of straight teeth. All four groups indicated that patients were the most responsible for the prevention of WSLs. All four groups indicated that the general dentist should be more responsible for the treatment of WSLs than the orthodontist. General dentists were significantly more likely to indicate that the orthodontist was most responsible for the prevention of WSLs (P <0.005).

The reported prevalence of decalcification in orthodontic patients varies from 2 to 96% mainly due to the lack of a standard examination technique. The aims of this study were: 1) to determine the prevalence of white spot lesions around brackets using visual examination and the DIAGNOdent; 2) to determine which teeth were the most susceptible to decalcification; and 3) to test the accuracy of the DIAGNOdent by comparing to the visual examination. The presence of white spot lesions was determined in two groups of patients who were 6 and 12 months into orthodontic treatment, respectively. The control group consisted of patients who were examined for white spot lesions immediately after having their braces placed on their teeth. The prevalence of white spot lesions was 38%, 46%, and 11% for the 6-month, 12-month, and control groups, respectively. There was a statistically significant correlation (r = 0.71) between the DIAGNOdent measurements and the visual examination.

Enamel damage and demineralisation are common complications associated with fixed orthodontic appliances. In particular, the clean-up of adhesive remnants after debonding is a recognised cause of enamel damage. Furthermore, fixed attachments offer retentive areas for accumulation of cariogenic bacteria leading to enamel demineralisation and formation of white spot lesions (WSLs). Bioactive glasses may be used to remove adhesives, preserving the integrity of the enamel surface, while also having the potential to induce enamel remineralisation, although their efficacy in both respects has received little attention. A systematic review evaluating the remineralisation potential of bioactive glasses was first undertaken. No prospective clinical studies were identified; however, a range of in vitro studies with heterogeneous designs were identified, largely providing encouraging results. A series of glasses was prepared with molar compositions similar to 45S5 (SylcTM; proprietary bioactive glass) but with constant fluoride, reduced silica and increased sodium and phosphate contents. These glasses were characterised in several tests and the most promising selected. This was designed with hardness lower than that of enamel and higher than orthodontic adhesives. Its effectiveness in terms of removal of composite- and glass ionomer- based orthodontic adhesives was evaluated against SylcTM and a tungsten carbide (TC) bur. This novel glass was subsequently used for remineralisation of artificially-induced orthodontic WSLs on extracted human teeth. The novel glass propelled via the air-abrasion system selectively removed adhesives without inducing tangible physical enamel damage compared to SylcTM and the conventional TC bur. It also remineralised WSLs with surface roughness and intensity of light backscattering similar to sound enamel. In addition, mineral deposits were detected on remineralised enamel surfaces; these acted as a protective layer on the enamel surface and improved its hardness. This layer was rich in calcium, phosphate, and fluoride; 19F MAS-NMR, confirmed the formation of fluorapatite. This is particularly beneficial since fluorapatite is more chemically stable than hydroxyapatite and has more resistance to acid attack. Hence, a promising bioactive glass has been developed.

Objectives: 1) To develop and investigate the bioactivities of a novel bioactive glass (BAG) composite designed as an orthodontic adhesive. 2) To investigate the preventive effect, and to test the bond strength of the adhesive. Methods: A novel, calcium and phosphate rich, and fluoride containing, bioactive glass (BAG) was prepared via the melt quench route and incorporated into an experimental resin to produce a light cured paste. The ratio of the resin to the powder was 20:80% respectively. The BAG powder was gradually replaced by a high fluoride and silica content glass (HSG) from 80%, to 60%, 50%, 40%, 25% and 0%. 90 disks (1.26mm thickness and 10mm diameter) were produced from each composition to be immersed in 3 solutions (demineralising artificial saliva pH=4 (AS4), remineralising artificial saliva pH=7 (AS7) and Tris buffer (TB) pH=7.3, 10 ml each. Measurements were taken at 10 time points (from 6 hours to 6 months) in 3 replicas in each solution. Ion release study was determined by ISE and ICP, and pH monitoring was conducted on the resulting solutions. Immersed disks were studied by FTIR, XRD, MAS-NMR and SEM for apatite formation. XMT were used to study the effects of this material on demineralisation/remineralisation in human enamel. Shear bond strength of the adhesive on bovine enamel were studied in different conditions using an Instron machine. Results: The pH increased with time for all the samples with BAG in all solutions and was linearly correlated to BAG loading. Ion release results revealed that the composite disks release up to 15ppm F-, 450ppm Ca2+ and 10ppm PO43- ions, and the release pattern is directly related to the immersion time, with the highest release found in AS4. FTIR spectra, XRD patterns and SEM images showed formation of apatite on all the BAG-resin disks, especially in AS4 and this increase with time. The MAS-NMR spectra indicated fluorapatite was also formed. The XMT studies showed that the novel material reduces demineralisation around the brackets by 80%. The shear bond strength of this novel material was comparable to that of Transbond XT. Conclusion: The novel BAG composites have significant long term releases of F-, Ca2+ and PO43- ions, especially in acidic conditions and form apatite (including FAP) in acidic and neutral solutions. This implies that the material has the potential as an orthodontic adhesive that can prevent white spot lesions around brackets.

OBJECTIVES: To compare the amount of fluoride, calcium and phosphate release and recharge of a fluoride containing bioactive glass composite to a conventional resin composite and a resin modified glass ionomer cement at different time points. Furthermore, bond strength of a fluoride containing bioactive glass composite, a conventional flowable composite, and a resin modified glass ionomer cement to metal orthodontic brackets was evaluated. METHODS: A fluoride containing bioactive glass (BG) was synthesized using a sol-gel method and mixed homogeneously with an unfilled resin. For ion release and recharge, resin modified glass ionomer (RMGIC), Photac Fil Quick Aplicap (3M/ESPE) and flowable composite (Control), Filtek Supreme Ultra (Kerr), were used for comparison. Disc shape samples were fabricated using custom aluminum mold (1 mm in thickness and 9 mm in diameter, (n=5 for each material) and stored in 15 mL deionized water at 37°C until the testing time. The amounts of fluoride, calcium, and phosphate ions released were evaluated at different time points: 1 hour, 24 hours, 2 days, 3 days, 4 days, 5 days 6 days and 7 days. At each time point, all of the storage solution was extracted, and 7.5 mL was used for fluoride release measurement and the remaining 7.5 mL for calcium and phosphate ion release measurements. After solution extraction, the samples were replaced in 15 mL fresh deionized water at 37°C until the next sampling time point. Ionic recharge was performed with 5% sodium fluoride varnish (FluoroDose, Centrix) and MI paste plus (GC) following the ion release-testing period. An ion meter with a Fluoride ionic selective electrode were used to determine fluoride concentration. A Microwave-Plasma Atomic Emission Spectrometer (MP-AES) was used to test the concentration of the calcium and phosphate. For the shear bond strength test, rectangular shaped ceramic samples with the dimensions of 2 mm x 12 mm x 14 mm (Vita Mark II, Vita) were fabricated. Standard edgewise-metal brackets (American Orthodontics) were bonded to the center of the ceramic samples using tested material (n=10 for each material). Excess material was removed, and the cementing materials were polymerized from each side for 20 seconds. Specimens were either stored in water for 24 hours at 37o C or went under thermocycling for 5000 cycles. After the storage period, the specimens were subjected to shear bond strength test using an Instron universal machine at a crosshead speed of 0.5mm/min. Loads to failure were recorded to calculate shear bond strength. Comparison of released/recharged ions and shear bond strength were done by ANOVA and Tukey-Kramer HSD (α = 0.05) using JMP Pro 13. RESULTS: RMGIC showed significantly higher fluoride release and recharge than BG composite and the control. BG showed significantly higher Ca and P ion release compared to RMGIC followed by composite. RMGIC and BG showed significant ion recharge capability compared to composite. For the shear bond strength, the control composite showed significantly higher shear bond strength than BG composite followed by RMGIC. Thermocycling significantly increase bond strength for RMGIC and control but not for BG composite. CONCLUSIONS: 1. A fluoride containing bioactive glass composite was fabricated that showed the ability of ion release and recharge. 2. There was a significant difference in the amount of ion release and recharge among tested materials at different time points. 3. Favorable fluoride, calcium and phosphate ion release and recharge of BG composite were maintained over the testing period. 4. BG composite showed favorable bond strength to orthodontic metal brackets. 5. Thermocycling had a significant influence in bond strength for the materials tested except for BG composite. / 2020-07-18T00:00:00Z

Orthodontic treatment may cause an increase in the rate of enamel decalcification on tooth surfaces, producing White Spot Lesions (WSL). Orthodontic patients are at a higher risk for decalcification because orthodontic appliances retain food debris which leads to increased plaque formation. Dental plaque, an oral biofilm formed by factors including genetics, diet, hygiene, and environment, contains acid producing bacterial strains with a predominance of Mutans Streptococcus (MS). MS and others metabolize oral carbohydrates during ingestion, the byproducts of which acidify the biofilm to begin a process of enamel decalcification and formation of WSL. This study tests if patients in orthodontic treatment at Temple University can be used as subjects for further longitudinal study of WSL risk factors. Twenty patients between the ages of ten to eighteen after three months or greater of treatment were enrolled to determine if duration of treatment, hygiene, sense of coherence, obesity, diet frequencies, age and gender correlated with development of WSL. Of these, age is positively correlated with the number of untreated decayed surfaces. WSL and plaque levels may negatively correlate with increased brushing frequency and duration, while flossing frequency demonstrated a statistically significant negative correlation. This population may be suitable for further study because of its high incidence of WSL (75%), however difficulty in enrollment and patient attrition necessitates that future studies be modified. / Oral Biology

Das Eingliedern festsitzender kieferorthopädischer Apparaturen macht das vorherige Anrauhen des Schmelzes notwendig. Das Ziel dieser Arbeit bestand darin zu ermitteln, ob ein zeit- und ausdehnungsbezogen überschüssiges kieferorthopädisches Ätzen des Schmelzes über die Fläche des zu befestigenden Brackets hinaus mit 30% Phosphorsäure zu einem erhöhten Risiko für White-Spot-Läsionen beitragen kann. Zusätzlich wurde getestet, inwieweit die Faktoren Zahnreinigung, Ätzdauer und Zeitdauer auf die mögliche Entstehung von White-Spot-Läsionen Einfluss nehmen. Für diese in-vitro-Studie wurden 90 extrahierte menschliche obere mittlere und seitliche Frontzähne verwendet. Die Zahnkronen mit einem Durchmesser von mindestens fünf mm wurden in Kunststoff eingebettet und mit Schleifpapier poliert. Es wurde jeweils eine Baseline-Messung mittels Quantitativer lichtinduzierter Fluoreszenz (QLF) durchgeführt, während der die Referenzbereiche für die nachfolgenden Messungen festgelegt wurden. Anschließend wurden die 90 Prüfkörper randomisiert in sechs Gruppen aufgeteilt. Drei Gruppen wurden täglich einer standardisierten Reinigung unterzogen und jeweils zu Versuchsbeginn 30 Sekunden, 15 Sekunden oder 0 Sekunden mit 30% Phosphorsäure angeätzt. Die Prüfkörper der anderen drei Gruppen wurden keiner Reinigung unterzogen und ebenfalls 30, 15 oder 0 Sekunden angeätzt. Während 42 aufeinanderfolgenden Tagen wurden alle Prüfkörper einem pH-Zyklus unterzogen: Die Demineralisation erfolgte für 60 Minuten. Hierauf folgte eine 120 minütige Remineralisation. Dieser Zyklus wurde drei Mal pro Tag durchgeführt. Nach dem letzten Zyklus wurden drei Gruppen mithilfe einer Zahnputzmaschine, die mit eingespannten Bürstenköpfen und einem Gemisch aus künstlichem Speichel und fluoridhaltiger Zahnpasta arbeitete, standardisiert gereinigt. Nach 2, 7, 14, 21 und 42 Tagen wurden die Fluoreszenzwerte der Schmelzoberflächen mittels QLF ermittelt. Bei der Auswertung der Messergebnisse zeigte sich ein signifikanter Einfluss  (p < 0,01) aller drei Faktoren (Reinigung, Ätzdauer, Versuchszeit) auf die Fluoreszenzwerte. Die Fläche der Demineralisation wurde nur durch die Ätzdauer signifikant beeinflusst. Der Einfluss der längeren Ätzdauer (30 Sekunden) verstärkte sich insbesondere bei den ungereinigten Prüfkörpern. Der DeltaQ-Wert wurde lediglich durch die verstrichene Versuchszeit in Kombination mit 30 sekündigem Ätzen signifikant beeinflusst (p < 0,02). Werden angeätzte Schmelzbereiche nicht von Bonding oder Bracket bedeckt, ist somit mit einer verstärkten Entstehung von White-Spot-Läsionen zu rechnen. Folglich ist bei der kieferorthopädischen Bracketbefestigung darauf zu achten, die Ätzfläche auf die Fläche des zu klebenden Brackets zu beschränken und Ätzzeiten von 15 Sekunden nicht zu überschreiten.

A white spot lesion (WSL) is defined as enamel porosity, which could be due to an enamel defect or an initial carious lesion. ICON® resin is a resin infiltrant that penetrates into the enamel porosity and seals the lesion, thus inhibiting the progression of caries. This method is micro-invasive; however, the resin is radiolucent and the clinician cannot detect the material using radiographs. In order to develop a radiopaque resin, understanding the pore size and pore structure in WSLs is helpful. Therefore, the aim of this study was to characterise: (1) the pore size and structure, (2) the incorporation of radiopaque agents into ICON® resin. Brunauer-Emmett-Teller (BET) and focused ion beam-scanning electron microscopy (FIB-SEM) were used to characterise the porosity in WSLs. The data showed the enamel prisms become more pronounced in the advanced areas of the WSLs and demineralisation occurs within or/and between the enamel prisms. The pore size could be as small as an enamel crystallite, 28x48nm. Nano-strontium hydroxyapatite (non-coated and coated) and strontium bioglass were made as radiopaque fillers and characterised using different techniques including fourier transform infrared spectroscopy (FTIR), BET, transmission electron microscopy (TEM), X-ray diffraction (XRD) and particle size measurements. The radiopaque fillers had micron-sized particles, which made them unsuitable for infiltration into WSLs despite their possible ability to remineralise the WSLs. Radiopaque monomers including bromine-methacrylate and tin-methacrylate were able to make ICON® resin radiopaque and they showed a similar viscosity, wettability and biocompatibility compared to ICON® resin. The X-ray microtomography (XMT) showed that the experimental radiopaque resins were able to infiltrate into the WSLs, artificial and natural lesions, and they could be detected using image subtraction. Backscattered electron (BSE) imaging after each step of application of materials showed that the etching pattern and etchant gel could be barriers for a successful infiltration of the resins into WSLs.

Purpose: This in vitro study evaluated the effectiveness of using a 37% phosphoric acid liquid etchant along with MI Paste Plus™ powered technology compared to using MI Paste Plus™ alone or to an artificially created saliva solution in decreasing the demineralization and enhancing the remineralization of artificial carious lesions created on extracted human teeth. The teeth were analyzed and compared using polarized light microscopy, quantitative light-induced fluorescence, and digital photography. Materials and Methods: One hundred three recently extracted non-carious human third molar teeth without observable white-spot lesions, decalcification, or dental fluorosis were selected for this twelve day study and randomly divided into four treatment groups as follows: Group 1 (Control) - Artificial saliva solution (27 teeth) Group 2 (MIP) - MI Paste Plus™ application for 30 minutes daily for 12 days (26 teeth) Group 3 (15MIP) - 15 second etch every third day and MI Paste Plus™ application for 30 minutes daily for 12 days (25 teeth) Group 4 (1MIP) - 1 minute etch on day one ONLY and application of MI Paste Plus™ for 30 minutes daily for 12 days (25 teeth). Results: Results of one<–>way ANOVA revealed there was a significant effect for the type of treatment on the lesion depth (p = 0.0027). The post-hoc Tukey-Kramer's test indicated there was a statistically significant difference between the two groups (15MIP and 1MIP) that incorporated an acid etch in combination with MI Paste Plus™ and the group with exposure to MI Paste Plus™ alone (MIP). In addition, results of one<–>way ANOVA showed that there was no statistically significant effect for type of treatment on the change in fluorescence (p = 0.1417) or the change in density (p = 0.1934). Conclusions: The results of the present study revealed there was a significant effect for the type of treatment on the lesion depth (p = 0.0027). However, the only significant difference found was between the two groups (15MIP and 1MIP) that incorporated an acid etch in combination with MI Paste Plus™ and the group with exposure to MI Paste Plus™ alone (MIP). Thus, daily applications of MI Paste Plus™, with or without an acid etch, did not produce a statistically significant difference in mean lesion depth when compared to the control (artificial saliva group). In addition, the results of the present study showed that there was no statistically significant effect for type of treatment on the change in fluorescence (p = 0.1417) or the change in density (p = 0.1934). Further research is needed to evaluate MI Paste Plus™ capability in prevention of demineralization and/or enhancement of remineralization by conducting randomized clinical trials.