Josef Freudenthaler

Color stability of different composite resin materials

STATEMENT OF PROBLEMnData are needed to better predict the color stability of current composite resin materials.nnnPURPOSEnThe purpose of this study was to evaluate the impact of different storage solutions on the color stability of different composite resin materials.nnnMATERIAL AND METHODSnDifferent restorative and adhesive composite resin specimens (dual-polymerizing self-adhesive resin cement, autopolymerizing resin-based composite resin, dual-polymerizing resin-based composite resin, nanohybrid composite resin, and microhybrid composite resin) were fabricated and stored in red wine, black tea, chlorhexidine, sodium fluoride, tea tree oil, or distilled water for 4 weeks at 37°C. Color parameters were measured with a colorimeter before and after storage. Total color differences and specific coordinate differences were expressed as ΔE, ΔL, Δa, and Δb. A 2-way and 1-way analysis of variance (ANOVA) with Bonferroni adjustment for multiple comparisons were applied for statistical calculations (α=.05).nnnRESULTSnRed wine caused the most severe discoloration (ΔE >10), followed by black tea with perceptible (ΔE >2.6) to clinically unacceptable discoloration (ΔE >5.5). Colored mouth rinses discolored the materials to a lesser extent with clinically acceptable values. Dual-polymerizing resin adhesives showed a higher amount of discoloration.nnnCONCLUSIONSnCurrent restorative and adhesive composite resin materials discolor over time under the influence of different storage solutions. The composition related to the polymerizing mode seemed to be a causative factor.

Shear bond strength of fluoride-releasing orthodontic bonding and composite materials

Several fluoride-releasing bonding materials are available for orthodontic bracket placement. These are supposed to prevent white spot lesions during therapy. The objectives of this in vitro study were to evaluate the shear bond strength (SBS) and failure mode of a recently introduced fluoride-releasing adhesive, as well as the comparison with established orthodontic adhesives. Sixty bovine mandibular incisors were randomly allocated to three groups (n = 20): stainless steel brackets were bonded with Transbond Plus Color Change Adhesive, Transbond XT, or Light Bond. A universal testing machine was used to determine the SBS at a crosshead speed of 1 mm/minute. After debonding, the adhesive remnant index (ARI) was used to assess the adhesive remaining on the brackets. One-way analysis of variance comparing the three experimental groups showed no differences between the bonding systems for mean SBS (P = 0.27). ARI scores showed more residual adhesive on the teeth bonded with the Transbond systems (P < 0.01). As the fluoride-releasing bonding system provided sufficient mean bond strength in vitro (19.9 MPa), it may be used as an additional prophylactic measure in orthodontic therapy. However, the clinical effectiveness of its fluoride release may be questionable, as the amount of fluoride required from a bonding material to be caries preventive is still unknown.

Influence of surface conditioning on ceramic microstructure and bracket adhesion

The objective of this study was to investigate the influence of different conditioning procedures on various ceramic microstructures and bracket adhesion. Ceramic specimens (feldspathic, leucite, leucite-free, and fluorapatite) were mechanically conditioned (n = 20 per ceramic type) with conventional hydrofluoric acid (5 per cent HF; 60/30 seconds), buffered hydrofluoric acid (9.6 per cent BHF; 60/30 seconds), or sandblasting (Al(2)O(3)/SiO(2) particles). Silane coupling agents were added for chemical conditioning before bracket bonding. Bracket adhesion was calculated with a shear test in a universal testing machine. The bracket-composite-ceramic interface was further evaluated using the adhesive remnant index (ARI). One specimen of each ceramic/conditioning combination was subjected to qualitative electron microscopy investigation. One-way analysis of variance followed by Tukeys honestly significant difference test were applied for inferential statistics. Conditioning with conventional 5 per cent HF or sandblasting resulted in significantly (P < 0.001) higher bond strengths (mean values: 34.11 and 32.86 MPa, respectively) than with 9.6 per cent BHF (mean value: 12.49 MPa). Etching time or sandblasting particles had no statistical (P > 0.001) influence on bond strength. Higher ARI scores were found in the conventional 5 per cent HF and sandblasted groups, when compared with the 9.6 per cent BHF group. Microscopic examination of the conditioned ceramic surfaces showed that leucite and leucite-free ceramics differed most with respect to their surface roughness, though without an influence on shear bond strength (SBS; P < 0.001). Bracket adhesion was mostly influenced by the conditioning procedure itself. Sandblasted ceramic surfaces showed sufficient conditioning and bracket adhesion; however, the increased bracket adhesion was associated with a risk of ceramic surface damage.

Influence of different conditioning methods on immediate and delayed dentin sealing

STATEMENT OF PROBLEMnData are needed to evaluate the effect of various conditioning methods on immediate and delayed dentin sealing.nnnPURPOSEnThe purpose of this study was to test bond strength and surface configuration of immediate and delayed dentin sealing surfaces after applying different surface conditioning methods.nnnMATERIAL AND METHODSnA total of 96 premolars were allocated to the immediate and delayed groups. The groups differed in the timing of dentin sealing. The immediate-group specimens were sealed with a self-etching adhesive immediately after preparation. The delayed-group specimens were sealed before the final ceramic restoration bonding. Provisional restorations were cemented on immediate-group and delayed-group specimens for 1 week. Four conditioning methods were used: polishing with fluoride-free pumice paste, airborne-particle abrasion with silicoated aluminum oxide, glycin, or calcium carbonate. After 24-hour storage, the shear bond strength was tested. The fractured specimens were optically inspected with a stereomicroscope. An optical 3-dimensional surface analysis was performed for quantitative and qualitative evaluation. A 2-way ANOVA with post hoc Tukey honestly significant difference tests for significant effects was performed to investigate effects of the 2 factors, sealing and conditioning, and their interaction (α=.05).nnnRESULTSnTwo-way ANOVA found significant differences between the sealing and conditioning groups. The immediate group had significantly lower bond strengths than the delayed group. In all groups, surface polishing produced the highest bond strengths, and airborne-particle abrasion with calcium carbonate produced the lowest. Fracture analysis found more failures in the adhesive layers in the immediate groups and a prevalence of mixed failures in the delayed groups. The surface analysis found significant abrasion and roughness when airborne-particle abrasion with silicoated aluminum oxide was used for immediate and delayed dentin sealing surfaces.nnnCONCLUSIONSnPolishing and airborne-particle abrasion with silicoated aluminum oxide or glycin are efficient methods in conditioning immediate and delayed dentin sealing surfaces. Airborne-particle abrasion with silicoated aluminum oxide leaves significant surface alterations on both types of surfaces.

Rebonding performance of different ceramic brackets conditioned with a new silane coupling agent

The objective of this study was to investigate the rebonding effect of a new silane coupling agent on various ceramic brackets bonded to ceramic specimen. Different ceramic brackets (Fascination 2, Clarity SL, and In-OvationC) were assigned to three groups: rebonding with new silane coupling agent, rebonding with conventional silane coupling agent, or regular bonding as control (n = 16). Bracket adhesion was calculated with a shear test in a universal testing machine. The bracket-composite-ceramic interface was evaluated using the adhesive remnant index score. One-way analysis of variance was applied for inferential statistics. Rebonding with the new silane coupling agent resulted in high shear bond strengths (SBSs; mean values: 37.44-41.24 MPa) and ceramic specimen fractures. Rebonding with the conventional silane coupling agent resulted in significantly (P < 0.001) lower clinically adequate SBS (mean values: 20.20-29.92 MPa) with the least ceramic specimen fractures. Regularly bonded ceramic brackets resulted in clinically adequate to high SBS (mean values: 17.06-41.56 MPa) depending on their bracket base design. Rebonded ceramic brackets showed sufficient SBS to ceramic specimen surfaces. However, increased bracket adhesion was associated with a risk of ceramic specimen surface damage. Therefore, ceramic brackets rebonded with the new silane coupling should be debonded cautiously using alternative debonding methods.

Secular trends in the European male facial skull from the Migration Period to the present: a cephalometric study

Secular trends in the facial skull over three Central European samples spanning more than 13 centuries were examined. Data were 43 conventional cephalometric landmark points for samples dating from 680 to 830 AD (29 male Avars), from the mid-19th century (49 adult Hapsburg Monarchy males), and from the 20th century (54 living Austrian young adult males). Analyses by standard methods of geometric morphometrics demonstrated shape differences by data and by size, with a strong interaction of these with sample, in that group mean differences were different for small and large individuals (allometry is different from period to period). The oldest sample, from the Migration Period, exhibited allometric features that may possibly be Turkic. There are implications for the orthodontist interested in growth trends or growth predictions in ethnically mixed patient samples.

Impact of extracorporeal shockwave therapy on tooth mobility in adult orthodontic patients: a randomized single‐center placebo‐controlled clinical trial

AIMnThis RCT investigated the effect of non-invasive extracorporeal shockwaves on tooth mobility in orthodontic patients after active treatment.nnnMATERIALS AND METHODSnSeventy-two adult patients were included in the study. Immediately after active orthodontic treatment, patients were assigned to a treatment or a placebo group based on block randomization. The orthodontic patients were required to be otherwise healthy. The region of interest was the anterior portion of the mandible. The treatment group received a single shockwave treatment with 1000 impulses while the placebo group was treated with an acoustic sham. Tooth mobility was evaluated over a period of 6 months using a Periotest and manual testing. Pocket probing depths, bleeding on probing and the irregularity index were also assessed.nnnRESULTSnTooth mobility reduced significantly over 6 months in both groups, but shockwaves achieved significantly more rapid reduction on manual testing. Probing depth was significantly reduced while the irregularity index remained stable. Bleeding on probing was significantly reduced in the treatment group. No anti-inflammatory effect could be derived due to possible initial group differences.nnnCONCLUSIONSnThe mobility of teeth aligned by orthodontic treatment reduces over time. Shockwave treatment appeared to reduce tooth mobility more rapidly.

Impact of extracorporeal shock wave therapy (ESWT) on orthodontic tooth movement—a randomized clinical trial

ObjectivesThis randomized clinical trial investigated the effect of extracorporeal shock waves on the amount of orthodontic tooth movement and periodontal parameters.Material and methodsTwenty-six adult orthodontic patients participated in this clinical trial; all of them receiving lower second molar mesially directed movement. The fixed orthodontic device included superelastic coil springs (200xa0cN) and miniscrews as temporary anchorage device. The active treatment group received a single shock wave treatment with 1,000 impulses in the region of tooth movement. The placebo group was treated with deactivated shock wave applicator with an acoustic sham. The study period lasted 4xa0months with axa0monthly data exploration.ResultsNo statistically significant difference in posterior-anterior tooth movement between the treatment and placebo group was seen during observation period. Gender had no significant influence on tooth movement in either group. No significant difference occurred in mesio-distal tipping and rotation, but a significant difference (pu2009=u20090.035) in bucco-lingual tipping of the molars was found. Periodontal status of the patients (sulcus probing depth, gingival index) did not significantly differ in both groups. The plaque index showed a significant difference (pu2009=u20090.003).ConclusionsSingle application of extracorporeal shock wave treatment was associated neither with a statistically significant acceleration of tooth movement nor with an altered periodontal status in vivo.Clinical relevanceShock waves showed no harmful effects in the investigated area. Their clinical use for lithotripsy during orthodontic therapy might be permitted.

The Impact of Education on the Perception of Facial Profile Aesthetics and Treatment Need

BackgroundThe purpose of this study was to evaluate the influence of education on the perception of various male and female Caucasian profiles with respect to attractiveness and treatment need.MethodsFour hundred questionnaires were distributed among six groups of raters (nonacademic laymen, academic laymen, preclinical students, clinical students, orthodontists, and maxillofacial surgeons). Male and female profile images were altered digitally in the sagittal and vertical dimensions resulting in nine different male and female profiles. The raters had to assess the images according to attractiveness and treatment needs.ResultsThree hundred four questionnaires were completed in this study. Age and gender of the rater had no significant influence on the perception of profile attractiveness. The different groups of raters perceived the Class I normodivergent profiles as most attractive. Significant differences in the perception of attractiveness were seen between laymen, orthodontists, and maxillofacial surgeons. The orthodontists and maxillofacial surgeons reported treatment needs the most. The orthodontists were most sensitive in discerning profiles.ConclusionAttractive male and female profiles are recognizable by any rater. Education seemed to have a significant influence on facial profile perception and recommendation for treatment need of unattractive profiles. Professionals should be aware of their judgment discrepancy to laymen.Level of Evidence IIIThis journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Geometric morphometrics of different malocclusions in lateral skull radiographs

BackgroundTo evaluate the role of craniofacial shape in malocclusion by application of geometric morphometrics to a set of two-dimensional landmarks and semilandmarks obtained from lateral skull radiographs.MethodsCephalometric radiograph tracings of 88 untreated Caucasians (age range 7–39xa0years) were assigned to four groups according to their occlusion: neutrocclusion, distocclusion, mesiocclusion, and anterior open bite. The geometric morphometric shape analysis incorporated 66 landmarks and semilandmarks, which underwent generalized Procrustes analysis, between-groups principal component analysis, thin-plate spline deformation grid visualization, permutation tests, and receiver operating characteristic curves.ResultsThe position and shape of the mandible contributed to differences between the distocclusion and mesiocclusion groups, whereas the maxillary shape showed less variation. The growth-related shape alteration during adolescence was most pronounced in the mesiocclusion group and least pronounced in the neutrocclusion group. The open bite group was associated with an altered orientation of the mandibular body and the maxilla,xa0 showed the most hyperdivergent maxillomandibular pattern but was not anxa0own skeletal entity. Despite clear differences in mean shape across the four groups, the individual distribution of craniofacial shape overlapped between the groups without discrete clusters.ConclusionsCraniofacial shape was clearly associated with dental malocclusion and showed considerable variation. Geometric morphometrics was a powerful research tool but for diagnosing individual malocclusion standard cephalometric measurements including overjet and overbite were equally or more efficient than geometric morphometric descriptors.ZusammenfassungHintergrundUntersuchung der kraniofazialen Formvariation und ihrer Assoziation mit 4 Okklusionstypen mittels geometrisch-morphometrischer Analysen zweidimensionaler Messpunkte auf seitlichen Schädelröntgenbildern.MethodikUntersucht wurden Durchzeichnungen der Fernröntgenseitenbilder von 88 unbehandelten Europäern im Alter zwischen 7 und 39 Jahren, die anhand ihrer Verzahnung 4 Gruppen zugeteilt worden waren: Neutralokklusion, Distalokklusion, Mesialokklusion und anterior offener Biss. Die geometrische Morphometrie bezog 66 (Semi-)Landmarken ein, diese wurden einer Prokrustesanalyse und einer “between-groups principal component analysis” unterzogen, in einem Thin-Plate-Spline-Deformationsgitter visualisiert und mit Permutationstests und ROC (“receiver operating characteristic”)-Kurven evaluiert.ErgebnissePosition und Gestalt des Unterkiefers trugen zu den primären Unterschieden zwischen der Distal- und Mesialokklusionsgruppe bei. Die Form der Maxilla dagegen zeigte deutlich weniger Variation. Wachstumsbedingte Formveränderungen während der Adoleszenz waren in der Mesialokklusionsgruppe am stärksten, in der Neutralokklusionsgruppe am wenigsten ausgeprägt. In der Gruppe mit anterior offenem Biss fiel eine Umorientierung des Corpus mandibulae und der Maxilla bei maximal hyperdivergentem Muster auf, doch stelltexa0diese Gruppe keine eigene skelettale Entität dar. Trotz klarer Unterschiede zwischen den morphometrischen Durchschnittsformen der 4 Okklusionsgruppen überlappten die individuellen Formkonfigurationen zwischen den Gruppen, ohne dass Cluster beobachtet wurden.SchlussfolgerungIn der vorliegenden Studie bestanden eindeutige Verknüpfungen zwischen kraniofazialer Form und Okklusionstyp, sie unterlagen aber erheblicher Variation. Die geometrische Morphometrie hat sich als effektive Forschungsmethode bewährt. Für die individuelle Diagnose einer Malokklusion waren jedoch kephalometrische Standardmessungen einschließlich Overjet und Overbite gleich effizient oder sogar effizienter als geometrisch-morphometrische Deskriptoren.