International Poster Journal of Dentistry and Oral Medicine, 02/2005

Objectives: The aim of this study was to evaluate tensile bond strength of six different dentin adhesives (Excite, Admira Bond, Clearfil New Bond, AdheSE, Xeno III, Syntac) combined with the corresponding composite material on perfused dentin in vitro. Methods: Ninety freshly extracted molars, stored in saline for a maximum of fourteen days after extraction were included. All teeth were specially prepared allowing the simulation of dentin perfusion. Dentin specimens with a total thickness of 3.5 mm were obtained under standardized conditions. The specimens were randomly assigned to six experimental groups of fifteen samples each: Group A: Excite/ Tetric; group B: Admira Bond/ Admira; group C: Clearfil New Bond/ Clearfil Core; group D: AdheSE/ Tetric; group E: Xeno III/ Esthet X; group F: Syntac/ Tetric. Tensile bond strength was measured 15 minutes after application and light curing of the composite material (colour A2) using an universal testing machine. Results: For the six test series following tensile bond strengths were evaluated (mean value and standard deviation in MPa): group A: 4.74 (± 1.81), group B: 4.62 (± 1.21), group C: 4.68 (± 1.04), group D: 2.59 (± 0.79), group E: 6.90 (± 1.33); group F: 3.87 (± 0.94). Statistical analysis showed a significant influence of the used material combination on tensile bond strength (p Keywords: bond strength, adhesives, perfused dentin

Objectives: The study was performed to compare tensile bond strength obtained between composite and bone using a dentin bonding agent (Clearfil New Bond) after different pretreatments concerning surface roughening and etching times in vitro. Methods: Four mandibles of freshly sacrificed pigs were used to prepare twelve specimens each using trephane burs under constant water cooling. After preparation the surface was sanded. Fourty-eight bone specimens with a total thickness of 4.0 mm (± 0.5 mm) and a cortical layer of 1.5 mm (± 0.2 mm) were obtained under standardized conditions. Each twelve specimens were assigned to four experimental groups (Group A1: sandpaper 1000 (fine), etching 30 seconds; group A2: sandpaper 1000, etching 60 seconds; group B1: sandpaper 220 (rough) , etching 30 seconds, group B2: sandpaper 220, etching 60 seconds). Tensile bond strength of the dentin adhesive was measured 15 minutes after application and polymerization of the composite material (Clearfil Core) using an universal testing machine. Results: Following tensile bond strengths were evaluated (mean values and standard deviations, printed in MPa): Group A1: 4.54 (± 1.93); group A2: 4.25 (± 1.80); group B1: 2.34 (± 0.83); group B2: 0.67 (± 0.34). Statistical analysis showed a significant influence of the used pretreatment technique on tensile bond strength (p Keywords: bond strength, dentin bonding agent, bone, pretreatment

Introduction: For the making of individual milled or cast dental treatments pure titanium is increasingly proved regarding technical and clinical aspects. Nearly all restaurative indications can be covered by using titanium. Because of comparatively unfavourable mechanical values (low 0.2% yield strength, low elastic modulus, low fatigue strength) cast RPDs made of pure titanium are still critically discussed and their metal frameworks have to be stronger dimensioned. The usage of titanium alloys offer new aspects. Due to their advantageous elastic properties by concurrent high mechanical strength titanium alloys seem to be more suitable for making cast RPDs. Objectives: TiAl6Nb7 is examined regarding their usage for cast prosthodontic treatments. Therefore on one hand capability of moldfilling, elastic behaviour and weldability and on the other first clinical surveillances are presented. Material and Methods: Two different titanium alloys (TiAl6V4 and TiAl6Nb7) are cast and analysed by the so called outflow test regarding to Meyer. The elastic behaviour is tested using a static bending test of clasp-profiles made of pure titanium, a cobalt-based alloy and titanium alloy (TiAl6Nb7). Therefore values of maximum deflection and appendant force are taken. A first probational welding is done to verify the joining of pure titanium and titanium alloy and in-between titanium alloy. Results: Even though a high viscosity of its melting, TiAl6Nb7 shows a good castability. The elastic behaviour of the titanium alloy shows a good proportion of elastic plasticity and rigidity that is important for designing cast RPD's. Welding of titanium alloys is possible but further examinations have to be done. Conclusions: The titanium alloy TiAl6Nb7 can be recommended for clinical appliance and is an option for conventional model cast alloys. Keywords: Titanlegierung

Evaluation of changes of profile and surface after orthognatic surgery is of high significance for the patient. Different techniques have been described, most of them with low impact for the patient. Due to the lack of reliable reference points and levels comparison of pre- and postoperative images were often impossible. The aim of the study was to perform pre- and postoperative three-dimensional surface analysis of the face followed by calculation of slices and section analysis using a non-radiation optical system. Surface analyses of the patients\' faces were done before and six months after surgery using a measuring system with a projection for special light patterns and two CCD cameras. The digitised data were demonstrated as realistic three-dimensional colour pictures and processed in the computer. The evaluation includes pictures resulting from fusion of data, subtraction images and cross-section analysis. A total of 23 patients were evaluated with this technique. Changes were quantified dependant on their locations and compared with the preoperative planning. It was demonstrated that reference points and levels could be defined using an occlusion registration device. The results revealed reproducable statements concerning operation dependent changes of every single point of the surface. With the help of this technique it is possible to analyze acute swelling as well as long term changes of the profile after osteotomies of the jaws and displacement of fragments. Keywords: Optisches Messsystem, Profilometrie, Dysgnathie, Gesichtsweichteile

Objectives: To test the hypothesis that the application of rubber-dam increases the proximal contact strengths. Methods: 74 consecutive patients of our department without periodontitis, who needed a direct posterior composite restoration participated in this study. The proximal contact strengths (PCS) were electronically evaluated by measuring the frictional forces during the removal of a 50±5µm thick straight metal band. PCS were measured at the site next to the restoration (R) and at the corresponding contact of the contra-lateral quadrant (C), which was taken as control. Measurements were taken at baseline (R0/C0), after the application of the rubber-dam (R1/C1), after wedging (R2/C2), after the application of the restorative material (R3/C3), immediately after the removal of the rubberdam (R4/C4) and 10 minutes later (R5/C5). Differences over time were tested by ANOVA followed by the post hoc Scheffé-test and differences between test and control side by the Wilcoxon-test for paired samples (p=0.05). Results: PCS changed with time from 2.26±1.45N (R0) to 3.83±2.34N (R1), 2.68±2.38 N (R2), 3.54±1.87N (R3), 2.31±1.35N (R4) and 2.08±1.26N (R5; p Keywords: rubberdam, proximal contact

Objectives: To test the inter- and intra-examiner reliability of a recently developed instrument for measuring the proximal contact strength (Tooth Pressure Meter: TPM). To measure proximal contact strength, the frictional forces at removal of a straight 0.05 mm thick metal matrix band inserted between adjacent teeth were recorded. Custom-written software in Excel (MS Office) was used for the construction of diagrams relating the force (N) to seconds (s). Methods: Ten healthy adults with complete dentition and no signs of periodontitis or caries volunteered in this study. All contacts between the canine and the second molar were measured from mesial to distal either in the upper right and lower left or in the upper left and lower right quadrant. The order was randomly selected. Without any prior calibration, the investigators measured all contact strengths within one hour in alternate order two times (T1 and T2) each. The sequence of the investigators was randomly given as well. The standard deviations of the single measurements between the first and the second measurement separately for both investigators were taken as intra-examiner reliability, the standard deviations of the single measurements between the two examiners at the first and second measurement were taken as inter-examiner reliability. Results: The intra-examiner reliability was 0.33±0.28 N for one and 0.36±0.31 N for the other investigator (n.s.; Wilcoxon test for paired samples). The inter-examiner reliability at T1 was 0.47±0.42 N and at T2 0.36±0.35 N (p=0.04). Conclusions: It is concluded that the TPM produced reliable results. The reduction of the inter-examiner reliability between T1 and T2 indicates, that calibration is necessary to generate more reproducible results. Keywords: proximal contact strenth, tooth pressure meter

Introduction: No information is available which factors influence the cleaning efficacy of interdental brushes. Aim: To evaluate in vitro the cleaning efficacy of interdental brushes in different types of interdental spaces. Methods: Interdental brushes with diameters of 2, 3, 4 and 5 mm (Curaden AG) were tested in 8 pairs of extracted human molars combined to simulate two types (isosceles and equilateral) of interdental spaces with 4 sizes each. After coating the teeth with a dye to simulate plaque, digital images were taken from the proximal surfaces in a highly standardized setup. The teeth were repositioned and the proximal surfaces were cleaned in a reproducible manner. Post-brushing images were taken as before. After digital subtraction, the cleaned area was measured by pixel count. Percentage of cleaned surface area was taken as cleaning efficacy. Results: The cleaning efficacy was 10.1± 7.8% (2mm), 16.8± 9.6% (3mm), 23.0± 9.7 % (4mm) and 22.5± 7.8% (5mm) in equilateral interdental spaces. In isosceles the cleaning efficacy was 13.2± 5.1% (2mm), 20.0± 4.7% (3mm), 26.6± 7.7 % (4mm) and 25.9± 7.0% (5mm), respectively. The differences between the different types of interdental spaces were statistically significant (Wilcoxon test for paired samples, p Keywords: interdental brushes, interdental spaces, cleaning efficacy

The aim of the study was to evaluate the association between the oral self care behaviour and acute cerebral ischemia. Methods: 303 consecutive patients with acute ischemic stroke (T) and 300 representative population controls (C) matched for age, gender, ethnicity and area of residence underwent a clinical and radiographic dental examination. A questionnaire was used by trained interviewers in a face-to-face interview to investigate all known and/or suspected risk factors for stroke and periodontitis as well as their oral self care behaviour. Results: There was no statistically significant difference between the groups in terms of the use of toothbrushes and toothpastes, flosses and interdental brushes or mouthrinses. In a multivariate model with "Preceding Stroke" (OR 10.38; 95%-CI 4.39-24.54; p Keywords: oral self care, ischemic stroke

Recent years have brought a worldwide increase in cross-border migration due to a globalised economy. Illegal migration of adolescents and young adults very often leads to crime and/or prostitution. This trend has triggered a growing demand in forensic medicine to assess the age of adolescents and young adults in crime procedures. The individuals examined are non-nationals without valid identification documents who do not know their age or are suspected of not giving their age correctly. Keywords: forensic age estimation, skeletal age, forensic medicine, forensic odontology

Objectives: Beside many advantages composite fillings are leaning to gap formation. To avoid any gap, the incremental polymerization became standard in recent times. The objective of this study was to visualize the stress, generated by polymerisation shrinkage, in the material of a model-cavity by a photo-elastic method. So it should be possible to compare the mechanical stress in the model-cavity material induced by different filling methods. Methods: Realistic volumed cavities (V=112mm3, C=0.92) of photoactive resin were examined by red circular polarized light. The bulk-technique, the incremental-placement and a new technique, a small volume light-insert (V=8,6mm 3) with light-guiding properties which was pre-exposed in bulk-fillings, were examined and compared. A conventional micro hybrid resin (Arabesk TOP) and an experimental nano-composite were used. A halogen lamp (850mW/cm²), a plasma-lamp (570mW/cm²) and a blue solid state laser (488nm/16mW) were used for light induced polymerization. Results: The results offer the highest stress evaluation on bulk-techniques. The stress induced by incremental polymerization was reduced in comparison to bulk polymerization. The light-insert, as a new method, offers equivalent results like incremental-technique. The results were evaluated by a statistical test of Kolmogoroff-Smirnoff and showed significant differences between bulk / incremental and bulk / bulk with light-insert placement at a level of 1%. The substituted light sources showed no significant influence. Conclusions: The photo-elastic method allowed a comparison of the stress in cavity material induced by different filling- and processing techniques. It could prove that there is a stress reduction through incremental fillings and an equivalent effect of the light-insert. The function of this insert may be interpreted as an efficient three-dimensional soft-start technique. Keywords: polymerization, stress, composite, model cavity, araldit, shrinking