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This preregistered ex vivo investigation examined the dentinal hybrid layer formation of a resinous infiltrant (Icon), with reference to both thickness (HLT) and homogeneity when combined with modified tunnel preparation (occlusal cavity only) and internal/external caries infiltration. The adhesives Syntac and Scotchbond MP were used as controls (Groups 1 and 3) or in combination with Icon (Groups 2 and 4). A split-tooth design using healthy third molars from 20 donors resulted in 20 prepared dentine cavities per experimental group. The cavity surfaces (n = 80) were etched (37% H 3 PO 4 ), rinsed, and air-dried. Rewetting with ethanol was followed by application of the respective primers. After labeling with fluorescent dyes, either Syntac Adhesive/Heliobond or Scotchbond MP Adhesive was used alone or supplemented with Icon. HLT, as evaluated by scanning electron microscopy, did not significantly differ (P > 0.05), and confocal laser scanning microscopy revealed homogeneously mixed/polymerized resin-dentine interdiffusion zones in all groups. Icon can be successfully integrated into an ethanol-wet dentine bonding strategy, and will result in compact and homogeneous hybrid layers of comparable thickness considered equivalent to the non-Icon controls, thus allowing for preservation of the tooth's marginal ridge and interdental space in the case of internal/external infiltration of proximal caries., (© 2024. The Author(s).)

Purpose: To investigate the possibility that ozone may have an adverse effect on the bond strength of orthodontic brackets and to determine the area of residual adhesive on teeth after the debonding of brackets., Methods: 60 extracted premolars teeth were used in this study. Resin coated APC brackets (3M) were bonded according to the manufacturers' instructions. Bonded teeth were randomly divided into two groups. The teeth in Group 1 were subjected to a 10-second dosage of ozone from the HealOzone unit (Kavo) after etching and to a further 10 seconds of ozone after bonding the brackets using a 5 mm delivery cup. Teeth in Group 2 were used as a control. Debonding was carried out using a testing instrument at a cross-head speed of 1 mm/minute., Results: The Mann-Whitney test revealed no significant differences in shear bond strength between the two groups (P = 0.337). The mean shear bond strength (11.66 MPa) of Group 1 (subjected to ozone) was not significantly different than the mean shear bond strength (10.88 MPa) of Group 2 (not subjected to ozone). A Pearson Chi-square test of the Adhesive Remnant Index (ARI) revealed no significant difference in residual adhesive among the groups tested.

Introduction: The purpose of this study was to evaluate 3-dimensionally the changes on tooth surfaces after debonding orthodontic brackets and after removing residual adhesive and finishing., Methods: Sixty premolars were randomly divided into 2 groups, and brackets were bonded according to the manufacturers' instructions. Two types of orthodontic adhesives were used: resin-modified glass ionomer cement (group 1) and resin-coated adhesive precoated brackets (group 2). The brackets were debonded on a testing machine at a cross-head speed of 1 mm per minute. Models were made of each tooth before bonding, after debonding, and after removal of residual adhesive. The models were scanned with a 3-dimensional laser scanning machine, and the scanned images were analyzed by using modified analytical software., Results: The Mann-Whitney test showed significant differences in adhesive thickness and enamel loss between the 2 groups (P <.001). The mean (+/- SD) thickness for group 1 was 31.2 microm (+/- 26.5 microm), and the mean (+/- SD) thickness for group 2 was 102.7 microm (+/- 79.71 microm). The means (+/- SD) for enamel losses after cleaning and finishing the enamel surfaces were 22.8 microm (+/- 17.67 microm) for group 1 and 50.5 microm (+/- 31.27 microm) for group 2., Conclusions: Adhesive thickness and enamel loss due to orthodontic procedures can successfully be measured in vitro by using 3-dimensional laser scanning technology.

Objectives: To evaluate masking effects of resin infiltration on labial white spot lesions (WSL), by comparing the latter with a remineralization approach (using hydroxyapatite and fluorides) and conventional oral care (using fluoride-free toothpaste). Method and materials: Fifteen patients with at least three WSL were enrolled for a within-person randomized controlled trial, thus allowing for intrapersonal comparisons. Each WSL per tooth in every patient was randomly assigned to one of the following groups. Group 1: lesions were resin-infiltrated with Icon (RI; DMG); Group 2: Remin Pro (RP; VOCO) was used as remineralizing agent; and Group 3 (control): affected teeth were brushed with Complete Care toothpaste (CC; Himalaya). RP and CC were applied by means of a polishing brush, using a low-speed handpiece (5 min), and these procedures were repeated chairside thrice daily for 7 consecutive days. Digital photographs were captured before and after lesion treatment under standardized conditions. The CIE L*a*b* color system was used to analyze the optical outcome, and intrapersonal color differences were statistically evaluated. Results: Compared to RP and CC, RI showed prompt and subjectively satisfactory color improvements, and this was primarily driven by L* and b* shifts. Statistical analysis of the objective color differences (ΔE*) between the three groups revealed significant differences for RI vs RP (P = .029), RI vs CC (P < .001), and RP vs CC (P = .001). Conclusion: Resin infiltration is considered a time-effective treatment option for esthetically camouflaging WSL, while RP and CC failed to improve lesion appearance and oral health in the current short-term trial. [ABSTRACT FROM AUTHOR]

Nanoparticles (NPs) are insoluble particles smaller than 100 nm in size. In order to prevent microbial adhesion or enamel demineralization in orthodontic therapy, two broad strategies have been used. These are incorporating certain NPs into orthodontic adhesives/cements or acrylic resins (nanofillers, silver, TiO2, SiO2, hydroxyapatite, fluorapatite, fluorohydroxyapatite) and coating surfaces of orthodontic appliances with NPs (i.e. coating bracket surfaces with a thin film of nitrogen-doped TiO2). Although the use of NPs in orthodontics can offer new possibilities, previous studies investigated the antimicrobial or physical characteristic over a short time span, i.e. 24 hours to a few weeks, and the limitations of in vitro studies should be recognized. Information on the long-term performance of orthodontic material using nanotechnology is lacking and necessitates further investigation and so do possible safety issues (toxicity), which can be related to the NP sizes. [ABSTRACT FROM AUTHOR]

Hydrogen peroxide (H2O2) is a powerful oxidising agent. It gives rise to agents known to be effective bleaching agents. The mechanisms of bleaching involve the degradation of the extracellular matrix and oxidation of chromophores located within enamel and dentin. However, H2O2 produces also local undesirable effects on tooth structures and oral mucosa. In clinical conditions, the daily low-level doses used to produce tooth whitening never generate general acute and sub-acute toxic effects. Genotoxicity and carcinogenicity only occur at concentrations that are never reached during dental treatments. Some transient adverse effects have been reported on the oral mucosa and the digestive tract if the product is swallowed. Local effects may occur on the oral mucosa and dental tissues during whitening, namely, pulp sensitivity, cervical resorption, release of selected components of dental restorative materials, and alteration of the enamel surface. Most of the local effects are dependent of the technique and concentration of the product so far used, but as the results of bleaching obtained are not stable, repeated treatments add to the adverse effects. The informed decision to administer or not and the control of bleaching effects should stand in the hand of dental surgeons and certainly not as it appears at present, as cosmetics sold without any restriction despite the potential health hazards of peroxides. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the possibility that ozone may have an adverse effect on the bond strength of orthodontic brackets and to determine the area of residual adhesive on teeth after the debonding of brackets. Methods: 60 extracted premolars teeth were used in this study. Resin coated APC brackets (3M) were bonded according to the manufacturers' instructions. Bonded teeth were randomly divided into two groups. The teeth in Group 1 were subjected to a 10-second dosage of ozone from the HealOzone unit (Kavo) after etching and to a further 10 seconds of ozone after bonding the brackets using a 5 mm delivery cup. Teeth in Group 2 were used as a control. Debonding was carried out using a testing instrument at a cross-head speed of 1 mm/minute. Results: The Mann-Whitney test revealed no significant differences in shear bond strength between the two groups (P= 0.337). The mean shear bond strength (11.66 MPa) of Group 1 (subjected to ozone) was not significantly different than the mean shear bond strength (10.88 MPa) of Group 2 (not subjected to ozone). A Pearson Chi-square test of the Adhesive Remnant Index (ARI) revealed no significant difference in residual adhesive among the groups tested. [ABSTRACT FROM AUTHOR]

Objectives: To monitor the electrical resistance of artificially demineralized enamel and root dentine after exposure to different fluoridated dentifrices and, using transversal microradiography, to quantify remineralization. Materials and methods: This in-vitro blind investigation used 20 extracted teeth (four groups of five each). Each group was exposed to one test dentifrice [Colgate PreviDent (5000 ppm F), Colgate Winterfresh gel (1100 ppm F), Fluocaril Bi-Fluoré (2500 ppm F) and placebo (without fluoride)] three times daily for three minutes for 4 weeks. In between exposure to the test dentifrices, teeth were stored in a saliva storage solution. An Electrical Caries Monitor measured the electrical resistance at baseline and during the four-week test period at weekly intervals. The measurements were log transformed and Duncan's multiple range test applied. Remineralization was quantified using transversal microradiography. Results: Log mean (SD) electronic carries monitor (ECM) measurements in enamel at baseline and after 4 weeks of exposure to the test dentifrices were 4.07(1.53) and 3.87(0.90) (Placebo-Fluocaril), 4.11(1.86) and 4.64(1.43) (Colgate Winterfresh gel), 4.81(0.9) and 4.21(1.20) (Fluocaril Bi-Fluoré), and 4.60(0.88) and 3.76(0.9) (Colgate PreviDent). Corresponding measurements in dentine were 2.13(0.89) and 3.06(0.87) (Placebo-Fluocaril), 1.87(0.63) and 2.88(1.32) (Colgate Winterfresh gel), 2.47(1.20) and 1.65(0.60) (Fluocaril), and 2.16(0.00), and 2.34(1.07) for Colgate PreviDent. Lesion depth (µm) after microradiography in enamel was 100.1 (Placebo), 50.6 (Colgate Winterfresh gel), and 110.2 (Fluocaril, and 97.1 (Colgate PreviDent), and corresponding values in dentine were 169.7, 154.8, 183.7, and 153.5. The correlation of ECM and microradiographic parameters was negative (p < 0.05). Conclusion: Exposure of artificially demineralized enamel and root dentine to fluoridated dentifrices and saliva storage solution resulted in remineralization as follows: Colgate Winterfresh > Colgate PreviDent > Placebo-Fluocaril > Fluocaril Bi-Fluoré. Remineralization in teeth of the Placebo dentifrice group may be attributed to the presence of calcium and phosphate ions in the saliva storage solution. [ABSTRACT FROM AUTHOR]