INTRODUCTION:Digital technologies are playing an increasingly significant role in everyday university life, offering a broad spectrum of possibilities for enhancing teaching and learning. In contrast to orthodontic clinical practice, however, university-level courses for dental students continue to rely predominantly on analogue diagnostic methods. Thus, this study aimed to investigate whether the integration of digital media in teaching increases student motivation and whether comparable or improved diagnostic outcomes could be achieved. MATERIAL AND METHODS:In this hypothesis-generating study, 80 students assessed a cephalometric radiograph and a dental model both digitally and using traditional analog methods, with a 2-week interval between the sessions. Following the second session, participants completed a questionnaire evaluating their experiences with both approaches including their motivation associated with each learning method. Primary and secondary endpoints were summarized descriptively. Considering the cross-over design of the study, a linear mixed-effects regression analysis was performed to evaluate whether the digital and analog methods yielded comparable learning effects, as assessed by various parameters, including ANB. The model incorporated a random intercept for each participant. RESULTS:The assessment outcomes for both diagnostic tools were comparable across the two methods. Notably, the digital evaluations tended to deliver more accurate results and were completed in significantly less time. The questionnaire showed that the students were more enthusiastic using digital methods during university lessons. CONCLUSIONS:Students' subjective motivation in the field of orthodontics has increased significantly as a result of the digital analysis. The time saving was significant, which was mentioned in the evaluation as particularly positive. Students were able to achieve comparable or even better results when using the digital web tool to evaluate teleradiographic images and orthodontic models.

Introduction Orthodontic fixed retainers are often a predilection site for calculus build-up. However, standardized protocol for professional mechanical plaque removal (PMPR) does not yet exist that takes into account the slight weakening of the adhesive bond. Material and Methods In this in-vitro study, three cleaning protocols were evaluated: Group A: ultrasonic stainless-steel tip (Piezon PS, EMS Dental); Group B: Polyetheretherketone (PEEK) ultrasonic tip (PI Max, EMS Dental); and Group C: sonic cleaning (SiroTip S1, Sirona Dental Systems). These protocols were assigned artificial lower canine-to-canine segments with individual Twistflex retainers bonded (n = 10/group). Following artificial ageing of the adhesive bond, artificial calculus was applied and removed according to the respective cleaning protocol. After repeating twice, adhesive bond strengths were analysed. Results The Kruskal-Wallis test showed that the choice of instrumentation significantly influences the integrity of the adhesive bond (p = 0.036). Post-hoc pairwise comparisons revealed that Group A had significantly higher shear bond strength compared to Group C (p = 0.028). Conclusions This in-vitro study shows that the type of the PMPR system used has a significant influence on the shear bond strength of fixed retainers. Ultrasound-driven stainless-steel scalers appear to be more gentle than sonic-driven devices. Clinical relevance In clinical practice, the accidental debonding of retainer attachments during PMBR is a frequent complication. The present in-vitro study investigates whether specific cleaning modalities can minimize the risk of compromising the adhesive bonding. Specifically, different cleaning modalities (ultrasonic versus sonic) and various tip materials are evaluated and compared.

Additive manufacturing enables the fabrication of patient-specific zirconia devices with integrated surface features; however, the biological effects of meso-scale topographies remain insufficiently understood. This in vitro study evaluated the influence of defined meso-scale surface modifications on osteoblast behavior using Digital Light Processing (DLP)-fabricated 3Y tetragonal zirconia polycrystal (3Y-TZP) and 5Y partially stabilized zirconia (5Y-PSZ). Planar control specimens and surfaces incorporating regularly distributed columnar structures (height: 100 µm; width: 40 µm; center-to-center spacing: 80, 120, and 160 µm; Mod-80, Mod-120, Mod-160) were fabricated and characterized after sintering. Cytotoxicity was assessed by elution testing and showed cell viability >98% for all groups. Osteoblast adhesion and proliferation (hFOB 1.19) were quantified using metabolic assays. Meso-scale modifications significantly increased early cell adhesion compared to planar controls (p < 0.05), with the strongest effect observed for Mod-160. No significant differences in proliferation rates were detected between groups (p > 0.05). Osteogenic differentiation was evaluated by RT-qPCR (RUNX2, ALPL, COL1A1, BGLAP), revealing material- and geometry-dependent responses. On 3Y-TZP, meso-scale structures, particularly Mod-160, were associated with sustained upregulation of BGLAP, whereas 5Y-PSZ exhibited less pronounced effects. Within the limitations of this in vitro study, meso-scale surface structuring of additively manufactured zirconia enhances early osteoblast adhesion without affecting proliferation and may influence osteogenic differentiation in a material-dependent manner.

(1) Background: Zirconia (ZrO2) is increasingly used in dental implantology due to its biocompatibility and favorable mechanical and biological properties. While subtractive and stereolithographic additive manufacturing techniques are well established, the application of Fused Filament Fabrication (FFF) for zirconia-based dental implants remains largely unexplored. (2) Methods: Cylindrical ZrO2 specimens were fabricated using three different manufacturing techniques: milling (MIL), Digital Light Processing (DLP), and FFF. Surface topography was analyzed via white-light interferometry. Human fetal osteoblasts (hFOBs 1.19) were cultured on the specimens to evaluate cell adhesion after 4 and 24 h, proliferation for 4 days, cell surface coverage after 4 and 24 h, and osteogenic gene expression (RUNX2, ALPL, and BGLAP) after 24 h, 48 h, 7 days, and 14 days. (3) Results: The FFF samples exhibited significantly higher surface roughness than the MIL and DLP specimens. After 24 h, enhanced cell adhesion and the highest proliferation rates were observed on FFF surfaces. At 14 days, gene expression analysis revealed elevated expression of BGLAP on FFF surfaces, suggesting advanced osteogenic differentiation compared to MIL and DLP. (4) Conclusions: The inherent surface roughness of FFF-printed zirconia appears to promote osteogenic activity without additional surface treatment. These findings suggest that FFF may constitute a viable manufacturing method for the fabrication of customized zirconia components in dental implantology, warranting further investigations, particularly regarding their mechanical performance.

Objectives Orthodontic retainers should restrict physiological tooth mobility as little as possible. While this has been investigated for multistranded retainers, there is a lack of data for novel CAD/CAM retainers. To address this, the present study compared the restriction of physiological tooth mobility in multistranded retainers and different CAD/CAM retainers.Material/methods One group of multistranded (n = 8) and five groups of CAD/CAM retainers (nickel-titanium (NiTi), titanium grade 5 (Ti5), polyetheretherketone (PEEK), zirconia (ZrO2), and cobalt-chromium (CoCr); each n = 8) bonded from canine to canine were investigated for their influence on vertical and horizontal tooth mobility using an in vitro model of a lower arch in a universal testing machine. Load-deflection curves were determined and statistically analysed.Results All retainers restricted tooth mobility to varying extents. The retainers had less of an influence on vertical tooth mobility, with less of a difference between retainers (14%-38% restriction). In contrast, significant (P <= 0.05) differences were observed between retainers in the restriction of horizontal tooth mobility. ZrO2 retainers had the greatest impact, restricting horizontal tooth mobility by 82% (68 +/- 20 mu m/100N), followed by CoCr (75%, 94 +/- 26 mu m/100N) and PEEK (73%, 103 +/- 28 mu m/100N) CAD/CAM retainers, which had comparable effects on horizontal tooth mobility. Ti5 (54%, 175 +/- 66 mu m/100N) and NiTi (34%, 248 +/- 119 mu m/100N) CAD/CAM retainers had less of an influence on horizontal tooth mobility, and were comparable to multistranded retainers (44%, 211 +/- 77 mu m/100N).Limitations This is an in vitro study, so clinical studies are needed to draw clinical conclusions.Conclusions Multistranded and CAD/CAM retainers have different effects on tooth mobility in vitro. These effects should be further explored in future in vivo studies.

Zirconia is an attractive material for the manufacturing of oral implants and patient-individual barriers for guided bone regeneration. This study compared osteoblast behaviour on additive manufactured and milled 3-mol % yttria-stabilized tetragonal polycrystal zirconia (ZrO2).Two groups of samples (O5 x 2 mm) were manufactured by stereolithography (LithaCon 230, Lithoz, Vienna, Austria) and subsequently heat-treated and sintered. One group remained superficially unmodified (AM-ZrO2unmod.), while the other was polished according to DIN EN ISO 6872 standard using automated grinding (AMZrO2-pol.). For comparison, milled samples (e.max ZirCAD LT, Ivoclar Vivadent, Schaan, Liechtenstein) were sintered and polished similarly (Mil-ZrO2-pol.). Surface roughness was characterized using tactile profilometry. Adhesion, proliferation and coverage of human fetal osteoblasts (hFOB 1.19) as well as expression of osteogenic marker genes ALPL and RUNX2 were determined (and statistically compared using Kruskal-Wallis-analyses and Dunn's Post-hoc-tests).The surface roughness of AM-ZrO2-unmod. Was 45 times higher than that of the polished groups. No significant differences were detected between the three groups regarding cell adhesion and proliferation. With regard to cell coverage, AM-ZrO2-pol. Significantly outperformed the two other groups (p < 0.05). ALPL- and RUNX2mRNA expression was insignificantly superior for AM-ZrO2-unmod. Compared to the two other groups. Therefor no detrimental effect on osteoblast behaviour caused by the investigated, acrylic binder-based 3D printing workflow was observed.

Objectives: To evaluate the fit of zirconia veneers made by either 3D printing or milling.Methods: A typodont maxillary central incisor was prepared for a 0.5-mm-thick veneer and was reproduced 36 times from resin. Restorations were designed with a 20-mu m-wide marginal and a 60-mu m-wide internal cement gap, and were made from 3D-printed zirconia (LithaCon 3Y 210, Lithoz, n = 24) and milled zirconia (Cercon ht, DentsplySirona, n = 12). For milled zirconia, a drill compensation was needed to give the milling bur access to the intaglio surface. The restorations were cemented, cross-sectioned, and the cement gap size was analyzed by two raters. Inter-rater reliability was studied at 12 3D-printed veneers (intraclass correlation coefficient, ICC, mixed model, absolute agreement). Twelve remaining 3D-printed restorations were compared with 12 milled restorations regarding fit at three locations: marginally, labially, and at the incisal edge (Mann-Whitney U-tests, alpha<0.05).Results: Inter-rater reliability was excellent, with an ICC single-measure coefficient of 0.944 (95%-confidence interval: [0.907; 0.966]). Gap sizes (mean +/- SD / maximum) were 55 +/- 9 / 143 mu m at the margins, 68 +/- 14 / 130 mu m labially, and 78 +/- 19 / 176 mu m at the incisor edge for 3D-printed veneers. For milled veneers, gap sizes were 44 +/- 11 / 141 mu m at the margins, 85 +/- 19 / 171 mu m labially, and 391 +/- 26 / 477 mu m at the incisor edge. At the margins, the milled veneers outperformed the 3D-printed restorations (p = 0.011). The cement gap at the incisor edge was significantly smaller after 3D printing (p < 0.001).Conclusions: 3D-printed zirconia restorations showed clinically acceptable mean marginal gaps below 100 mu m. Because drill compensation could be omitted with 3D printing, the fit at the sharp incisal edge was significantly tighter than with milling. Clinical significance: The fit of 3D-printed ceramic anterior restorations meets clinical standards. In addition, 3D printing is associated with a greater geometrical freedom than milling. With regard to fit this feature allows tighter adaptation even after minimally invasive preparation.

During orthodontic tooth movement, mechanically induced remodeling occurs in the alveolar bone due to the action of orthodontic forces. The number of factors identified to be involved in mechanically induced bone remodeling is growing steadily. With the uncovering of the functions of neuronal guidance molecules (NGMs) for skeletal development as well as for bone homeostasis, NGMs are now also among the potentially significant factors for the regulation of bone remodeling during orthodontic tooth movement. This narrative review attempts to summarize the functions of NGMs in bone homeostasis and provides insight into the currently sparse literature on the functions of these molecules during orthodontic tooth movement. Presently, four families of NGMs are known: Netrins, Slits, Semaphorins, ephrins and Eph receptors. A search of electronic databases revealed roles in bone homeostasis for representatives from all four NGM families. Functions during orthodontic tooth movement, however, were only identified for Semaphorins, ephrins and Eph receptors. For these, crucial prerequisites for participation in the regulation of orthodontically induced bone remodeling, such as expression in cells of the periodontal ligament and in the alveolar bone, as well as mechanical inducibility, were shown, which suggests that the importance of NGMs in orthodontic tooth movement may be underappreciated to date and further research might be warranted.

Background: Induced tooth movement during orthodontic therapy requires mechano-induced bone remodeling. Besides various cytokines and growth-factors, neuronal guidance molecules gained attention for their roles in bone homeostasis and thus, potential roles during tooth movement. Several neuronal guidance molecules have been implicated in the regulation of bone remodeling. Amongst them, Semaphorin 3A is particular interesting as it concurrently induces osteoblast differentiation and disturbs osteoclast differentiation. Methods: Mechano-regulation of Sema3A and its receptors PlexinA1 and Neuropilin (RT-qPCR, WB) was evaluated by applying compressive and tension forces to primary human periodontal fibroblasts (hPDLF) and alveolar bone osteoblasts (hOB). The association of the transcription factor Osterix (SP7) and SEMA3A was studied by RT-qPCR. Mechanisms involved in SEMA3A-mediated osteoblast differentiation were assessed by Rac1GTPase pull-downs, β-catenin expression analyses (RT-qPCR) and nuclear translocation assays (IF). Osteogenic markers were analyzed by RT-qPCR. Results: SEMA3A, PLXNA1 and NRP1 were differentially regulated by tension or compressive forces in hPDLF. Osterix (SP7) displayed the same pattern of regulation. Recombinant Sema3A induced the activation of Rac1GTPase, the nuclear translocation of β-catenin and the expression of osteogenic marker genes. Conclusion: Sema3A, its receptors and Osterix are regulated by mechanical forces in hPDLF. SEMA3A upregulation was associated with Osterix (SP7) modulation. Sema3A-enhanced osteogenic marker gene expression in hOB might be dependent on a pathway involving Rac1GTPase and β-catenin. Thus, Semaphorin 3A might contribute to bone remodeling during induced tooth movement.

Purpose Surface sealants are widely used as a prevention strategy and are indicated for young patients with insufficient oral hygiene who also need plaque removal by professional tooth cleaning. The aim of this study was to evaluate discoloration of surface sealants by plaque disclosing solutions and to test to what extent this discoloration can be reduced again by professional tooth cleaning. Methods In all, 96 extracted lesion-free human teeth were randomly assigned to treatment with either Pro Seal® (PS; Opal Orthodontics, South Jordan, UT, USA) or Opal®Seal™ (OS; Reliance Orthodontic Products, Itasca, IL, USA). Color evaluations after application of the plaque disclosing solution Mira-2-Ton® (Hager & Werken, Duisburg, Germany) were performed using a clinical spectrophotometer. Staining and polishing were repeated once. Color differences (∆E) above 3.77 were regarded as clinically relevant. Results All sealants showed high, clinically relevant ∆E values after the first staining. Polishing led to significantly decreased ∆E values on PS-treated teeth; however, the median ∆E value remained above the clinically relevant threshold. Polishing on OS-treated teeth only slightly reduced ∆E values. After professional tooth cleaning both PS and OS showed clinically relevant ∆E values. Conclusion Surface sealants show clinically relevant discoloration after exposure to plaque disclosing solution under in vitro conditions. Such discolorations could not be removed by professional tooth cleaning. Thus, in clinical practice, plaque disclosing solutions might cause esthetic deficits in surface sealant-treated teeth. The impact of plaque disclosing solutions under clinical conditions (e.g., in the presence of saliva and by various aspects of a person’s nutrition) should be investigated in clinical studies.

Objectives The aim of this single-center randomized controlled trial (NCT03753256) was to assess orthodontic surface sealant layer thickness and integrity in vivo during a 12-month follow-up by optical coherence tomography (OCT). Materials and methods Using a split-mouth design, quadrants of 20 patients treated with fixed orthodontic appliances were included. Quadrants were randomly assigned to the sealants Pro Seal® (PS) or Opal® Seal™ (OS). OCT scans were performed immediately after the application of the sealants and after 3, 6, 9, and 12 months. Sealant layer thicknesses and their integrity were determined at 5 regions of interest (ROIs) known for high risks of demineralization. Sealant integrity loss was determined using a self-developed scale. Results A total of 16 patients successfully completed the study. The studied sealants showed significant differences in initial layer thickness. Mean layer thickness was significantly lower for PS (67.8 μm, (95% CI, 56.1–79.5)) than for OS (110.7 μm, (95% CI, 97.3–124.1)). Layer thickness loss was significant after 3 months for PS and after 6 months for OS. Sealant integrity was compromised in more than 50% of the ROIs already after 3 months for both sealants. Conclusions Patients treated with fixed orthodontic surface sealants lost the integrity of the protective layer in more than 50% of cases after 3 months, and the layer thickness of the sealants was significantly reduced after 3–6 months. Clinical relevance The protective effect against demineralization lesions of orthodontic sealants in patients treated with fixed appliances appears to be limited in time. Further preventive measures should be investigated. Trial registration ClinicalTrials.gov (NCT 03753256)

BACKGROUND:The integrity of orthodontic surface sealants after professional tooth cleaning (PTC) has previously only been evaluated in vitro. Recently, we have shown that optical coherence tomography (OCT) can successfully be used for the longitudinal assessments of sealant thickness in vitro and in vivo.OBJECTIVES:Thus, the aim of the present study was to assess the sealant thickness after PTC in vitro and in vivo by OCT.TRIAL DESIGN:Single-centre four-arm parallel-group randomized controlled trial.METHODS:Ninety-six extracted human teeth were randomly assigned to the surface sealants Pro Seal® (PS) and Opal® Seal™ (OS) and to PTC protocols: (1) polishing with brush and prophy paste (Cleanic®) or (2) erythritol air-polishing. Sealant thickness was assessed by OCT immediately after application (baseline), after thermocycling and after polishing for totals of 5, 10, 15, 30, 60, 90, and 120 seconds. Additionally, a clinical trial was conducted. Therefore, using a split-mouth design, quadrants of 20 patients and PTC protocols were randomized by an external randomization centre using computer generated tables to assign the surface sealants and PTC protocols. Sealant thicknesses were analysed at baseline, before and after PTC. Due to the optical properties of sealants, a complete blinding was not feasible.RESULTS:In vitro both sealants revealed significant layer thickness losses after both PTC protocols. PS lost 0.77 µm/s [95% CI (confidence interval): 0.67, 0.87] from air-polishing and 0.43 µm/s (95% CI: 0.37, 0.49) from polishing with brush while OS lost 0.44 µm/s (95% CI: 0.32, 0.55) from air-polishing and 0.79 µm/s (95% CI: 0.68, 0.89) from polishing with brush of layer thickness. Sealant thickness loss of was significantly higher after erythritol air-polishing for PS and after polishing with brush for OS. The results of a concurrent randomized controlled trial (RCT) were comparable to those achieved in the in vitro part of this study.LIMITATIONS:Long-term surface sealant abrasion should be validated by additional RCTs.CONCLUSIONS:For PTC on surface sealant treated teeth, low abrasive protocols should be used. Air-polishing should be avoided on PS protected teeth and polishing with brush on OS treated teeth.TRIAL REGISTRATION:ClinicalTrials.gov NCT03753256.

OBJECTIVES:Demineralizations such as white spot lesions are among the most prevalent side effects during orthodontic treatment. Fluorescence devices, including quantitative light-induced fluorescence (QLF), exploiting the intrinsic fluorescence of enamel and teeth and most recently optical coherence tomography (OCT) were introduced for early demineralization detection. In addition to near-infrared OCT scanning, multicolor modules allow for imaging with different laser wavelengths and the detection of reflective- and fluorescent light. The aim of this study was to evaluate a modified multicolor ophthalmic OCT device for the detection of early carious lesions in vitro and in vivo.MATERIALS AND METHODS:Twenty-seven extracted lesion free human teeth were randomly assigned to three different demineralization protocols. Carious lesion detection was performed using macrophotography, OCT, and reflectance/fluorescence imaging using green laser and blue laser light. In addition, teeth of 5 orthodontic patients were OCT scanned, and fluorescence imaging using blue laser light was performed to assess demineralization after orthodontic therapy.RESULTS:Both in vitro and in vivo, OCT allowed for precise determination of lesion depth and enamel loss. Fluorescence imaging using blue laser light was most sensitive for the detection of early demineralization in vitro and in vivo. However, established and severe demineralizations were also reliably detected by macrophotography in vitro and in vivo.CONCLUSION:Demineralization can be detected with high sensitivity using blue fluorescence imaging with multicolor OCT devices.CLINICAL RELEVANCE:In the future, OCT fluorescence imaging might be considered for longitudinal monitoring of dental hard tissue during orthodontic treatment in clinical trials.

Surface sealants are widely used in orthodontic practice to avoid enamel decalcifications in patients treated with fixed orthodontic appliances. While their clinical benefit was tested in several studies, their biocompatibility has been evaluated to a lesser extent. Therefore, the aim of this randomized prospective study was to evaluate possible adverse biological effects of three commonly used surface sealants and a bonding primer on gingival tissues by analysing cytokines in crevicular fluid of orthodontic patients after the application of surface sealants. A single centre parallel trial was conducted. Using a split-mouth design quadrants of 15 patients requiring orthodontic treatment with fixed appliances were randomized to one of three commonly used surface sealants (Pro Seal®, Opal®Seal™, Protecto®CaF2Nano) and a bonding primer (Transbond™ XT). Interleukin (IL)-8 and IL-10 levels in crevicular fluids of the individual quadrants were assessed at four different time points (before application, and at 30, 60 and 90 min after application). In all, 60 quadrants of 15 patients were randomized (Pro Seal® n = 15, Opal®Seal™ n = 15, Protecto®CaF2Nano n = 15, Transbond™ XT n = 15) and analysed. No significant changes for IL-8 or IL-10 levels in crevicular fluid after the application of surface sealants or bonding primer were detected. However, interpatient variability was high. No further clinical side effects were detected. Commonly used pre-bonding surface sealants (Pro Seal®, Opal®Seal™) do not appear to have a significant impact on inflammatory cytokines levels of crevicular fluid and do not appear to contribute to sensitization or hypersensitivity events.

Placement of composite resin restorations in deep subgingival cavities can damage surrounding soft tissues. In addition, commonly used resin-based composites (RBCs) might interfere with wound healing and periodontal health. To clarify cellular interactions with RBCs, we used an MTT assay to investigate adhesion of primary human gingival fibroblasts and human osteoblasts (hFOB 1.19) on five RBC materials with and without surface modifications (alumina blasting with 50- or 110-μm Al2O3). In addition, high-performance liquid chromatography (HPLC) was used to determine release of resin monomers from RBCs after 1 h, 1 day, and 7 days. As compared with tissue culture plastics (the control), cellular adhesion was significantly lower (P < 0.001) for human gingival fibroblasts and osteoblasts. Only minor, nonsignificant differences between individual RBCs were identified. HPLC analyses identified the release of three bifunctional methacrylates bisphenol A glycerolate dimethacrylate, triethylene glycol dimethacrylate, and diurethane dimethacrylate from RBCs and showed that monomer release increased between 1 h and 1 day but remained low. The present findings suggest that surface adhesion in the subgingival area is limited for the tested RBCs. Although residual monomer release was low for all tested RBCs, it might be sufficient to adversely affect cell adhesion.

Optical coherence tomography (OCT) is a clinical standard in ophthalmology. Currently, its application in dentistry is gaining increasing interest. In this study, we tested the possibility to use a modified commercially available spectral domain OCT (SD-OCT) to assess the layer thickness of orthodontic surface sealants.

IntroductionThe aim of this pilot study was to investigate psychological and biological changes after application of a surgery-first orthognathic treatment approach.MethodsA prospective cohort study of 9 patients (6 women and 3 men; mean age 26.7 years) suffering from skeletal Class II and III deformities was conducted. Skeletal changes from pre-to post-treatment were analyzed based on data acquired by use of cone-beam computed tomography (CBCT). Psychological changes were analyzed using the orthognathic quality of life (OQLQ) questionnaire, Sense of Coherence 29-item scale (SOC-29) and longitudinal day-to-day questionnaire. For biological evaluation, concentrations of IL-1 β, IL-6, TGF β 1-3, MMP-2 and VEGF were assessed in crevicular fluid by bead-based multiplex assays at one preoperative and various postoperative time points.ResultsA significant improvement (P = 0.015) in quality of life, as measured with the OQLQ, was observed between baseline and 3 months post-surgery. The most affected dimensions were: facial aesthetics (p = 0.022), oral function (p = 0.051) and social aspects (p = 0.057). Sense of coherence (SOC) significantly improved after treatment by 9 points (P = 0.029). Despite the significant improvement in OQLQ and SOC during the course of the study, the personal experience of appearance varied distinctly in course and intensity. In accordance with the temporal pattern of fracture healing, the analysis of crevicular fluid revealed an increase in pro-resorptive factors (IL-1 β, IL-6 and MMP-2) at early postoperative time points, while remodeling factors (members of the TGF-β superfamily) were detected at later postoperative time points.ConclusionsOrthognathic treatment using the surgery-first approach has a positive impact on patient's psychosocial status. Accelerated tooth movement after surgery might, to a certain extent, be due to elevated levels of bone remodeling factors with overlapping functions during fracture healing and tooth movement.

Root resorptions are common undesirable side effects of orthodontic treatment. In most patients, these defects are repaired by cementoblasts. However, in 1–5 % of patients, the repair fails. The repair mechanism is not well understood. Apoptosis of cementoblasts might contribute to an impaired repair of root resorptions induced by orthodontic forces.

PURPOSE:To evaluate the effects of aqueous storage on shear bond strength (SBS) and monomer release of fiberreinforced composites (FRCs).MATERIALS AND METHODS:Four unidirectional FRCs were tested, including one semi-interpenetrating polymer network (IPN) (ES, everStick) and three cross-linked polymer (CLP) FRCs (GT, GrandTec; TF, TenderFiber; DP, Dentapreg). The SBS of samples of original resin to fresh FRC with an intact oxygen inhibition layer (n = 30/group) and repair resin to FRC after surface treatment (n = 30/group) was evaluated after 6 and 12 months of storage in artificial saliva. Monomer release of polymerized resin-coated and uncoated FRCs was detected by high-performance liquid chromatography after immersion for 1 h, 1 day, and 7 days.RESULTS:After 6 months, a significant decrease in SBS was seen with ES-repair (p < 0.0001). After 12 months, significant decreases were seen with ES-original (p < 0.0001), ES-repair (p < 0.0001), and TF-repair (p = 0.0003). A significant reduction was also found for GT-original (p = 0.0254) and GT-repair (p = 0.0176). At 6 and 12 months, GT showed the highest SBS values, with DP-repair being statistically similar to GT at 12 months. For UDMA and bis- GMA, the greatest amounts of release were seen in uncoated specimens, followed by flowable resin-coated and viscous resin-coated specimens.CONCLUSION:Matrix composition, interfacial bonding, and resin coverage seem to account for differences in the aging behavior of FRCs. The semi-IPN material is likely to suffer most from the challenging oral conditions. CLP FRCs might be more stable over the long term. Coverage of FRCs with viscous resin is highly recommended to reduce residual monomer release.

Repair materials for extensive cervical root defects may come in direct contact with periodontal tissues. This in vitro study compared the effects of four calcium silicate cements (CSC), one resin-modified glass ionomer cement, and one glass carbomer cement on primary human gingival fibroblasts (HGF), alveolar osteoblasts (HAO), and a human osteoblast cell line (hFOB 1.19).