Background Risk of enamel damage that often accompanies ceramic brackets debonding raises the demand of finding an optimal method for debonding of them without adverse effects. Different techniques were proposed in an attempt to facilitate their debonding. Comparison of these techniques is crucial. The aim of this study was to evaluate and compare different techniques for debonding of ceramic brackets in terms of shear bond strength and adhesive remnant index. Materials and methods A total of 100 extracted premolars were randomly allocated into 5 groups. Ceramic brackets were then bonded to teeth using light cure composite resin. Among test groups; group I: served as control, group II: chemical aided debonding via peppermint oil, group III: ultrasonic aided debonding, group IV: diode laser aided debonding, and group V: Er:YAG laser aided debonding. Brackets were shear tested using universal testing machine followed by ARI assessment and evaluation of enamel microstructure was performed using scanning electron microscopy. Results A significantly lower shear bond strength was found in ultrasonic, diode, and Er:YAG laser groups. However, no significant difference was found in the chemical group. A significantly higher adhesive remnant index was found solely in Er:YAG laser group with minimal enamel microstructure alterations. Conclusions Er:YAG laser is a promising tool in debonding ceramic brackets. Ultrasonic and diode laser significantly reduced shear bond strength. Yet, adhesive remnant index in both groups revealed no difference. Chemical aided debonding had little effect and hence, it cannot be recommended without further development.

Background The purpose of this 2-arm-parallel split-mouth trial was to evaluate and compare the extent of possible root resorption using dentin phosphoprotein levels in gingival crevicular fluid between controlled continuous and intermittent orthodontic force groups. Materials and methods A sample of 16 maxillary first premolars from 8 patients requiring bilateral extractions of the upper first premolars as part of their orthodontic treatment were recruited. A buccally directed continuous force of 150 g, reactivated after 28 days, was applied to the upper first premolar on one side for 8 weeks. On the contralateral first premolar, a buccally directed intermittent force (21 days on, 7 days off) of the same magnitude was applied for the same period. Gingival crevicular fluid samples were collected at the beginning of the study, 1st, 3rd, 4th and 5th week, and at the end of the study to quantify and compare dentin phosphoprotein levels in both groups. Results Dentin phosphoprotein levels showed a higher concentration in the continuous force group than the intermittent force group in week 4 and 8 of sample collection; where the differences were statistically significant (95% CI 0.007–0.14; P < .04) and (95% CI 0.02–0.17; P < .04) respectively. No harm was observed. Conclusions Dentin phosphoprotein was found to be a useful early biomarker to detect and monitor root resorption, showing that the application of an intermittent orthodontic force caused less root resorption than a continuous force. Trial registration NCT04825665 ClinicalTrials.gov. Registered 1 April 2021—Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT04825665.

Objective:Objective: Objective: Objective: An in vitro study to evaluate the microleakage at the occlusal and gingival margins of both polycarbonate and metallic brackets bonded with light-cured resin modified glass ionomer cement versus light cured composite.Materials and Methods: Materials and Methods: Materials and Methods: Materials and Methods: 40 extracted sound premolars were divided into 2 groups. Group I was bonded with polycarbonate brackets (silkon M TM). 10 samples using light cure Fuji ortho (IA) and 10 samples using Trans bond XT (IB). Group II was bonded with metal brackets using both techniques (IIA&IIB). All samples were then subjected to thermo cycling. The root apices were sealed with sticky wax and the teeth were painted with 3 layers of nail polish leaving a 1mm window surrounding the bracket. Teeth were then immersed in 0.5% basic fuchsine dye solution for 24 hours at room temperature then washed under running water and sectioned longitudinally between the bracket wings into two halves using a low speed thin diamond disc under a stream of water. The extent of dye penetration was detected using a light stereomicroscope (x18 magnification) at both the occlusal and gingival areas of the brackets between both the enamel adhesive and the bracket adhesive interphases using soft imaging analysis. Descriptive statistics were computed as means and standard deviations of micro leakage values in different groups. Pooled micro leakage allowed the use of ANOVA, Tukey Volume 42 -December 2012 HSD test and the general linear model test at p<0.05. Significance level was set at 5%. Statistical analysis was done using SPSS version 17.Bar charts with Error bars were used for graphical presentation. Results:Results: Results: Results: The gingival side of all groups exhibited higher microleakage compared with the occlusal side for both adhesive interfaces. All bracket and adhesive combinations displayed statistically significant differences in microleakage between the enamel-adhesive and adhesive-bracket interfaces at the occlusal and gingival sides of the brackets. When the adhesive systems were compared, the Resin Modified Glass Ionomer cement (RMGIA) showed more microleakage than the light cured composite resin between the different interfaces. The polycarbonate brackets with the addition of ceramic fillers showed more microleakage than metallic brackets. Conclusion:Conclusion: Conclusion: Conclusion: The overall comparison of the bonding system used revealed that no combination was found to be superior in their microleakage inhibition property, and polycarbonate brackets even by addition of ceramic fillers seemed that it was still inferior to the metallic brackets in the microleakage inhibition property.

Objectives: This study was done to compare between the effectiveness of using highly filled and lightly filled sealants in preventing demineralization and resisting acid and abrasion through assessing enamel color change differences and sealant retention after induced challenges. Methods: 100 human premolars were collected and allocated into 2 groups. The buccal surfaces of the 1 st group were sealed with a 38% filled sealant (Opal ® Seal TM) and the 2 nd group with an 18 % filled one (PRO SEAL ®). Both groups were exposed to acidic and abrasive challenges. Enamel color changes were recorded spectrophotometrically at baseline (T0), after sealant application (T1), after first exposure to acidic challenge (T2), and after second exposure to acidic challenge and simulated toothbrushing (T3). Standardized photographs were taken for each tooth under ultraviolet light at baseline and at (T3). Teeth images were analyzed using computer software to estimate sealant coverage and fluorescence loss. Results: The best protection was seen in the Opal seal group after the 1 st acidic challenge (p=0.000) when compared with PRO SEAL. Greater sealant material loss (68.78% ± 15.54) and fluorescence loss (82.46% ± 11.04) were seen in the PRO SEAL group (p=0.000). Both sealants changed the original enamel color similarly and exceeded the clinically detectable threshold (∆E=3.7). Conclusion: Based on the results of this study; increasing the filler content strengthens the sealant, therefore, offering more protection against white spot lesions. Both sealants degrade with increasing the challenges. Both sealants change the initial enamel color similarly.

Objective: To compare different techniques for debonding of ceramic brackets in terms of adhesive remnant index (ARI).Material and methods: A sample of 100 extracted human premolars were randomly and equally allocated into 5 groups of 20. Thereafter, monocrystalline ceramic brackets were bonded to teeth using light cure composite resin. Among the 5 groups; group I: served as control, group II: chemical assisted debonding using peppermint oil, group III: ultrasonic assisted debonding, group IV: diode laser assisted debonding, and group V: Er: YAG laser assisted debonding. Brackets were then debonded using a universal testing machine, followed by ARI assessment. Results: A statistically significant higher ARI scores was found solely in Er:YAG laser assisted debonding. Yet, no significant difference was found with chemical, ultrasonic, and diode laser assisted debonding.Conclusion: Er:YAG laser could be effective for debonding of ceramic brackets. Hence, this method might be recommended to alleviate enamel damage.