[Forensic dentistry for identity verification. A survey at the state police level]. / Verwendung von forensischer Zahnmedizin zur Identitätsfeststellung. Eine Befragung auf Ebene der Länderpolizei.

BACKGROUND: In Germany, the identification of unknown dead persons is the responsibility of the police. According to INTERPOL standards, primary (e.g., DNA, fingerprints, and teeth) and secondary (e.g., tattoos) characteristics are examined. Forensic dentistry is already used internationally as an efficient method. In this study, the approach of state police in Germany was analyzed. The methods used for identification, the role of forensic dentistry, the cooperation with dentists, and possible optimization approaches are investigated. METHODS: By means of a digital questionnaire, police officers competent in all federal states for the discovery of unknown dead bodies were asked about identification methods and specifically about the use of forensic dentistry. RESULTS: Eighty-five officers from at least 11 federal states participated in the survey. The procedure turned out to be department specific. In 72.6% of the cases, different characteristics are combined in the identification process, most frequently DNA with dental status (37.1%). DNA analysis is used most frequently. Of the respondents, 62.9% agreed that dental identification is used "often." The percentage of identifications using dental status is estimated to be 1.6-8.1%. For forensic dentistry, 19.4% have a fixed point of contact. A digital platform to contact dentists was estimated to be helpful by 56.5%. DISCUSSION: Forensic dentistry is currently still lagging behind DNA analysis, which could change through increasing digitalization if, for example, ante-mortem data are more reliably available and platforms for interdisciplinary exchange are created.

Impact of Dental Anxiety on Dental Care Routine and Oral-Health-Related Quality of Life in a German Adult Population-A Cross-Sectional Study.

The interaction between dental anxiety and the establishment of a consistent dental care routine has been an ongoing challenge. Unfortunately, there is limited available data concerning the detailed dental care practices of individuals with dental anxiety. Therefore, this study aims to explore how dental anxiety influences dental care habits and oral-health-related quality of life within an adult population. By utilizing the Dental Anxiety Scale (DAS) and the German Oral Health Impact Profile (OHIP-G5), we assessed their extent. To evaluate the differences, we performed analyses of variance (Anova), an independent t-test and rank correlation. The findings of this study unveil a significant correlation between elevated DAS scores and reduced frequency of tooth brushing; calculus removal and appointments for professional teeth cleaning. Interestingly; the use of dental floss and mouthwash solution as well as toothbrush hardness appeared to be not significantly affected by dental fear. Moreover, individuals with dental anxiety demonstrated a preference for manual toothbrushes over electric ones. In addition, higher DAS scores were found to be strongly associated with greater OHIP-G5 scores, thus leading to a substantial decline in overall oral health-related quality of life.

Influence of cold atmospheric-pressure-plasma in combination with different pretreatment methods on the pull-off tensile load in two-piece abutment-crowns: an in-vitro study.

BACKGROUND: In implant prosthetic dentistry, the adhesive connection of individualized ceramic crowns and prefabricated titanium bases leads to several benefits. However, the durability of the bonding could be a weak point and especially depends on sufficient surface pretreatment. Cold atmospheric-pressure plasma (CAP) is a pretreatment method that should improve the surface properties without physical damage. Thus, the purpose of this study was to investigate the influence of CAP treatment on pull-off tensile load in two-piece abutment crowns. METHODS: Eighty zirconia crowns and titanium bases were divided into eight groups (n = 10) according to their surface pretreatment prior to cementation with Panavia V5: no treatment (A); sandblasting (B); 10-MDP primer (C); sandblasting and primer (D); CAP (AP); sandblasting and CAP (BP); CAP and primer (CP); sandblasting, CAP and primer (DP). The specimens were thermocycled (5°/55°, 5000 cycles), and then the pull-off tensile load (TL) was measured. Statistical analyses were performed using three-way ANOVA with Tukey post-hoc and Fisher's exact tests. RESULTS: The results showed that the TL was highest in group D (p < 0.0001). Some combinations of different treatments led to effects that were greater than the sum of the individual effects. These effects were modified by interactions. Only in combination with primer, CAP treatment had a small but positive significant effect (group CP vs. C and CP vs. AP, p < 0.0001) which however did not come close to the strong interaction effect that resulted from the combination of sandblasting and primer. CONCLUSION: Within the limitations of this study, CAP treatment cannot be recommended in this specific field of indication due to its unreliable influence on TL in combination with other pretreatment methods.

Forensic Identification: Dental Scan Data Sets of the Palatal Fold Pairs as an Individual Feature in a Longitudinal Cohort Study.

The INTERPOL standard for the identification of unknown individuals includes the established primary characteristics of fingerprint, DNA, and teeth. Exposure to noxious agents such as fire and water often severely limits the availability of usable material such as fingerprints. In addition to teeth, the protected oral cavity also houses palatal fold pairs, which are the subject of this study to demonstrate individuality and consequently support identification. Material and Methods: In this cohort study, 105 participants' palates were scanned twice with a dental intraoral scanner (Omnicam SIRONA®) over a 3 month period and were then analyzed using a matching program. The intraindividual and interindividual differences were determined, and the mean values and standard deviations were calculated and presented. Results: The intraindividual differences are highly significantly lower than the interindividual differences (p < 0.0001). Conclusions: Within the limitations of this study, the results suggest that palatal rugae pairs can be considered a highly individual feature and could be considered an identification feature in a young and healthy population.

Effectiveness and Safety of Over-the-Counter Tooth-Whitening Agents Compared to Hydrogen Peroxide In Vitro.

(1) This study investigated the whitening effect, cytotoxicity and enamel surface alterations induced by different over-the-counter (OTC) bleaching agents in comparison to hydrogen peroxide. (2) Human teeth (n = 60) were randomly assigned into 6 groups (n = 10), stained with coffee solution for 7 d, followed by a whitening period of 7 d with either placebo, bromelain, sodium bicarbonate, sodium chlorite, PAP or hydrogen peroxide. Color measurements were performed with a spectrophotometer. Scanning electron micrographs (SEM) were taken to assess the enamel structure. Cytotoxicity of the tested substances was assessed based on the cell viability of primary human fibroblasts. (3) The application of all whitening gels resulted in a greater color difference of the enamel (ΔE) in comparison to the negative control. Hydrogen peroxide caused the greatest color difference. Bromelain and PAP treatment showed no enamel surface changes, in contrast to hydrogen peroxide treatment, which showed very mild interprismatic dissolution. Bromelain was the only non-cytotoxic agent. (4) The maximum effect achieved by all OTC bleaching agents was the removal of stains, whereas hydrogen peroxide was capable of further whitening the teeth. Bromelain treatment was neither cytotoxic, nor resulted in enamel surface alterations, and its whitening effect was less, yet still effective, compared to hydrogen peroxide.

Retentive Strength of CAD/CAM-Fabricated All-Ceramic Crowns Luted on Titanium Implant Abutments Using Different Ceramic Materials and Luting Agents: An In Vitro Study.

Objectives: This study aimed to determine the retentive strength of monolithic hybrid-all-ceramic crowns luted on titanium implant abutments. Material and Methods: In total, 450 crowns (75 each of Mark II, Empress CAD, e.max CAD, Suprinity, Enamic, Celtra Duo) were milled using a CAD/CAM system. The crowns were cemented onto sandblasted titanium implant abutments using five luting agents (Multilink Implant, Variolink II, RelyX Unicem, Fujicem, and Panavia 2.0). After thermocycling was performed (5000 cycles: 5−55 °C, 30-s dwell time), the crowns were removed using a universal testing machine. The location of luting-agent residue on the abutment and inner crown surfaces was evaluated. Analyses of variance (ANOVA) with the Bonferroni correction were performed to evaluate differences of retentive strength depending on the crown material and the kind of the luting agent. Results: The retentive strengths for the different ceramic materials were Vita Mark II: 652N-759N (SD:134N-146N), Empress CAD: 681N-822N (SD: 89N-146N), e.max CAD: 784N-1044N (SD: 109N-176N), Vita Enamic: 716N-1177N (SD: 132N-220N), Vita Suprinity: 867N-1488N (SD: 202N-278N), and Celtra Duo 772N-1335N (SD:151N-229N). After the removal trials, the visual documentation showed different adhesive residue location depending on the ceramic materials. Furthermore, the pull-off force was dependent on the choice of adhesives. No significant differences were found between different luting agents and the ceramic material Vita Mark II and Empress CAD. EmaxCAD showed significant differences with Unicem and FujiCem compared to Panavia, as did VitaSuprinity, VitaEnamic, and Celtra Duo (p < 0.001). Conclusions: The ceramic material used seems to influence the retentive strength and the use of certain luting agents results in a higher retentive strength for some ceramic materials.

Marginal and Internal Precision of Zirconia Four-Unit Fixed Partial Denture Frameworks Produced Using Four Milling Systems.

BACKGROUND: CAD/CAM systems enable the production of fixed partial dentures with small and reproducible internal and marginal gaps. PURPOSE: The purpose of this study was to evaluate the reproducibility of the marginal and internal adaptations of four-unit fixed partial denture frameworks produced using four CAD/CAM systems. MATERIALS AND METHODS: Prepared dies of a master model that simulated the loss of the first left molar were measured. Fifteen frameworks were manufactured using four CAD/CAM systems (A-D). The internal fit was determined by the replica technique, and the marginal gap was determined by microscopy. ANOVA was carried out to detect significant differences, and the Bonferroni adjustment was performed. The global level of significance was set at 5%. RESULTS: The mean gap size ranged from 84 to 132 µm (SD 43-71 µm). The CAD/CAM systems showed significant variance (p < 0.001), and system A (VHF) showed the smallest gaps. The smallest gaps for each system were in the molar part and in the marginal region of the frameworks (p < 0.001). CONCLUSIONS: The CAD/CAM systems showed significantly different gap sizes, particularly between premolars and molars and among the marginal, axial and occlusal regions. All of the systems are suitable for clinical application.

Does the Modification of the Apical Geometry of a Dental Implant Affect Its Primary Stability? A Comparative Ex Vivo Study.

(1) Background: Primary stability-one fundamental criterion for the success of dental implants-is influenced by implant geometry even if the effect of apical shape modifications on implant primary stability has not yet been examined. Therefore, the aim of the ex vivo study was to compare primary stability of implants differing in apically located screw threads (J-line) or a flat tip (K-line) only. (2) Methods: 28 implants of each group of the same diameter (4.3 mm) were randomly inserted into porcine bone blocks. The first group (9, 11 and 13 mm) was inserted into "hard", the second (11 mm) into "soft" bone, here using a normal and an undersized drilling protocol. Insertion torque (Ncm), Periotest® value, resonance frequency (implant stability coefficient, ISQ) and push-out force (N) were measured. (3) Results: In "hard" bone, primary stability increased with increasing length in both groups but it was significantly higher in J-line (p < 0.03). An undersized preparation of the implant bed in "soft" bone resulted in a significant increase in primary stability in both groups. Here, J-line also showed a significantly increased primary stability when compared to equally prepared K-line (insertion torque: 37 Ncm vs. 26 Ncm; Periotest®: -6.5 vs. -4.3; push-out force: 365 N vs. 329 N; p < 0.05 each). (4) Conclusions: Primary stability is significantly higher with increasing implant length and apically located screw threads as well as with undersized drilling protocols. When preparing the implant site and subsequently selecting the implant system, modifying factors such as implant geometry (also at the tip) should be taken into account.

The reproducibility of electronic color measurements of the marginal gingiva.

INTRODUCTION: This study evaluated the reproducibility of electronic color determination system evaluations of the marginal gingiva, which could be important for adhesive cervical fillings or prosthetic restorations that imitate the gingiva. MATERIAL AND METHODS: In 50 subjects, the L*, a*, and b* color coordinates were evaluated five times at a point in the marginal area of a central incisor using different electronic color determination systems: (SP) Shadepilot, (ES) Easyshade, (CE) Crystaleye, and (SV) X-Rite. The mean color difference (ΔE) and its standard deviation between the five measurements from each participant were calculated separately for each device. Further ICC for interdevice reliability was determined. RESULTS: The L*, a*, and b* color coordinates and ΔE values differed significantly among the systems (p < 0.001). Within each patient and measurement system, ΔE ranged from 1.4 to 3.2 (SD 1.1-2.5), L* from 2.6 to 5.7 (SD 2.6-5.7), a* from 11.9 to 21.3 (SD 3.6-3.9), and b* from 15.1 to 28.9 (SD 1.7-4.3). Interdevice reliability ranged between 0.675 and 0.807. CONCLUSIONS: Color determination of the marginal gingiva using the electronic tooth color determination systems tested herein showed limited reproducibility. The results obtained with the different measurement systems differed enormously. CLINICAL RELEVANCE: These results show that the electronic color measurement devices tested allow no high reproducible determination of color coordinates of the marginal gingiva.

Potential risk factors for early and late dental implant failure: a retrospective clinical study on 9080 implants.

BACKGROUND: The aim of this study was to analyze potential risk factors for early and late dental implant failure (DIF) in a clinical cohort trial. In a private practice, 9080 implants were inserted during a period of 10 years. In case of DIF, data were classified into early and late DIF and compared to each other in regard of gender, age, site of implantation, implant geometry, and patients' systemic diseases. RESULTS: Three hundred fifty-one implants failed within the observation period (survival rate: 96.13%). Early DIF occurred in 293 implants (83.48%) compared to late DIF in 58 implants (16.52%). Significant earlier DIF was seen in the mandible (OR = 3.729, p < 0.001)-especially in the posterior area-and in younger patients (p = 0.017), whereas an increased likelihood of late DIF was associated with maxillary implants (OR = 3.729, p < 0.001) and older patients. CONCLUSIONS: Early DIF is about twice as common as late DIF. Main risk factors for early DIF are implant location in the (posterior) mandible as well as younger age. On contrary, late DIF is rather associated with older patients, cancellous bone quality, and longer implants.

Novel Low-Twist Bast Fibre Yarns from Flax Tow for High-Performance Composite Applications.

The use of natural fibres for components subjected to higher mechanical requirements tends to be limited by the high price of high-quality semi-finished products. Therefore, the present study deals with the development of more cost-effective staple fibre yarns made from flax tow. In the subsequent processing stage, the yarns were processed into quasi-unidirectional (UD) fabrics. The results of the fibre characterisation along the process chain have shown that no significant mechanical fibre damage occurs after slivers' production. Fibres prepared from yarns and fabrics show comparable characteristics. The yarns were processed to composites by pultrusion to verify the reinforcement effect. The mechanical properties were comparable to those of composites made from a high-quality UD flax roving. The fabrics were industrially processed into composite laminates using a vacuum infusion and an autoclave injection process (vacuum injection method in an autoclave). While impact strength compared to a reference laminate based on the UD flax roving was achieved, tensile and flexural properties were not reached. An analysis showed that the staple fibre yarns in the fabric show an undulation, leading to a reorientation of the fibres and lower characteristic values, which show 86-92% of the laminate made from the flax roving. Hybrid laminates with outer glass and inner flax layers were manufactured for the intended development of a leaf spring for the bogie of a narrow-gauge railroad as a demonstrator. The hybrid composites display excellent mechanical properties and showed clear advantages over a pure glass fibre-reinforced composite in lightweight construction potential, particularly flexural stiffness.

Effects of ceramic layer thickness, cement color, and abutment tooth color on color reproduction of feldspathic veneers.

AIM: To optimize the esthetics of ceramic restorations, it is important to determine accurately the effects of various parameters on the final color of the restoration. However, there is a lack of information on what determines the color of translucent feldspathic veneers formed using ceramics such as Vita Mark II. The aim of this study was to evaluate the effects of the ceramic layer thickness, cement color, and abutment tooth color on the color of the feldspathic ceramic veneer restoration. MATERIAL AND METHODS: A total of 30 all-ceramic monolithic veneers (Vita Mark II) were fabricated using a CAD/CAM system. The crowns were divided into three groups of differing ceramic thickness (0.4-, 0.7-, and 1.0-mm thick). Each type of crown was seated on six different-colored abutment teeth (1M1 [reference], 1M2, 2M2, 3M2, 4M2, and 5M2) using seven different try-in paste colors. The color of the resulting restoration was evaluated using spectrophotometry with a spot-measurement device (Vita Easyshade Advance 4.0). Color data are expressed in CIE L*a*b* system coordinates, and color differences ΔE relative to the reference tooth were calculated and analyzed using one-way analysis of variance (ANOVA) with the Bonferroni post hoc test at α = 0.05. RESULTS: The color difference ΔE of the feldspathic all-ceramic veneer system was significantly affected by the thickness of the ceramic layer, the cement color, and the abutment tooth color (P < 0.05). The smallest values of ΔE compared with the reference color were found when try-in pastes shade -3 was used. As the thickness of the ceramic layer increased, a significant decrease in ΔE was found. As the color of the abutment tooth varied from light to dark, a significant increase was found in ΔE. CONCLUSION: The thickness of the ceramic layer, the cement color, and the abutment tooth color significantly affected the color of the resulting CAD/CAM feldspathic ceramic veneer restoration.

Preload, Coefficient of Friction, and Thread Friction in an Implant-Abutment-Screw Complex.

PURPOSE: To examine the screw preload, coefficient of friction (COF), and tightening torque needed to overcome the thread friction of an implant-abutment-screw complex. MATERIALS AND METHODS: In a customized load frame, 25 new implant-abutment-screw complexes including uncoated titanium alloy screws were torqued and untorqued 10 times each, applying 25 Ncm. RESULTS: Mean preload values decreased significantly from 209.8 N to 129.5 N according to the number of repetitions. The overall COF increased correspondingly. There was no comparable trend for the thread friction component. CONCLUSION: These results suggest that the application of a used implant-abutment-screw complex may be unfavorable for obtaining optimal screw preload.

Reliability of visual and instrumental color matching.

OBJECTIVE: The aim of this investigation was to evaluate intra-rater and inter-rater reliability of visual and instrumental shade matching. MATERIALS AND METHODS: Forty individuals with normal color perception participated in this study. The right maxillary central incisor of a teaching model was prepared and restored with 10 feldspathic all-ceramic crowns of different shades. A shade matching session consisted of the observer (rater) visually selecting the best match by using VITA classical A1-D4 (VC) and VITA Toothguide 3D Master (3D) shade guides and the VITA Easyshade Advance intraoral spectrophotometer (ES) to obtain both VC and 3D matches. Three shade matching sessions were held with 4 to 6 weeks between sessions. Intra-rater reliability was assessed based on the percentage of agreement for the three sessions for the same observer, whereas the inter-rater reliability was calculated as mean percentage of agreement between different observers. The Fleiss' Kappa statistical analysis was used to evaluate visual inter-rater reliability. RESULTS: The mean intra-rater reliability for the visual shade selection was 64(11) for VC and 48(10) for 3D. The corresponding ES values were 96(4) for both VC and 3D. The percentages of observers who matched the same shade with VC and 3D were 55(10) and 43(12), respectively, while corresponding ES values were 88(8) for VC and 92(4) for 3D. CONCLUSIONS: The results for visual shade matching exhibited a high to moderate level of inconsistency for both intra-rater and inter-rater comparisons. The VITA Easyshade Advance intraoral spectrophotometer exhibited significantly better reliability compared with visual shade selection. CLINICAL SIGNIFICANCE: This study evaluates the ability of observers to consistently match the same shade visually and with a dental spectrophotometer in different sessions. The intra-rater and inter-rater reliability (agreement of repeated shade matching) of visual and instrumental tooth color matching strongly suggest the use of color matching instruments as a supplementary tool in everyday dental practice to enhance the esthetic outcome.

Comparison of visual shade matching and electronic color measurement device.

OBJECTIVE: The objective of this study was to compare the performance of visual shade matching and spectrophotometric measurements. MATERIALS AND METHODS: A total of 100 observers matched pairs of corresponding shade tabs from two VITA classical A1-D4 shade guides. The tab identifiers on one shade guide were masked. Lack of visible color differences between the corresponding tabs was confirmed by means of an intraoral spectrophotometer. Means and standard deviations were calculated. Analysis of variance (ANOVA) (α = 0.05) with a Bonferroni correction was performed to detect significance of differences between groups. RESULTS: A total of 72.5% of tab pairs (or 11.6 tabs) were matched using the visual method, and 98.9% were matched using the spectrophotometer (P < 0.001). Female observers showed significantly better results than male observers (P = 0.027). Both genders showed the highest visual scores in group B, followed by groups C, A, and D. CONCLUSIONS: Instrumental shade-matching systems have the potential to improve color matching in dentistry. Results were influenced by gender. CLINICAL RELEVANCE: The dental spectrophotometer exhibited a significantly higher percentage of correct matches of corresponding shade tabs compared with conventional visual shade matching.

Primary Stability of Cylindrical and Conical Dental Implants in Relation to Insertion Torque-A Comparative Ex Vivo Evaluation.

INTRODUCTION: The aim of this ex vivo study was to investigate the influence of different insertion torques on primary stability of a conical and a cylindrical implant system. MATERIALS AND METHODS: Thirty-two dental implants (Astra Tech OsseoSpeed 5.0 S × 11 mm cylindrical [n = 16] and 5.0 × 11 mm conical [n = 16]) were inserted with 20, 30, 40, and 45 N·cm into fresh porcine bone of mixed trabecular-cortical quality. Before insertion, bone quality was assessed via cone beam tomography. After insertion, resonance frequency analysis was reported using the implant stability quotient (ISQ). Implant insertion depths were evaluated, and the implants were pushed out of the bone by force (measured in N). All experiments were done with n = 4 per group. RESULTS: The highest ISQ (mean 78.25 ± 2.9) and pushout values (mean 675 N ± 5.8) were measured for the cylindrical implant after insertion using 30 N·cm. The conical implant showed the highest primary stability by means of ISQ (mean 76.25 ± 2.2) and pushout force (mean 502.5 N ± 9.6) after an insertion torque of 40 N·cm. If more insertion force was used, primary stability was reduced in all cases. CONCLUSION: The data indicate that different forms of an implant system need different insertion torques to obtain an optimal primary stability. These results have to be verified clinically.

Polygonal Area of Prosthesis Support with Straight and Tilted Dental Implants in Edentulous Maxillae.

PURPOSE: The aim of this in vitro study was to assess the increase in the polygonal area of implant-retained prosthesis supports in edentulous maxillae with the use of tilted distal implants compared with the use of straight distal implants, using a variety of implant lengths. MATERIALS AND METHODS: A total of 25 DICOM datasets of atrophic edentulous maxillae were provided. Bone augmentations in the molar region had to be avoided. Two straight reference implants were virtually inserted in the anterior region. Two additional implants were placed far distally on both sides (4 groups: [1] straight, 12-mm length; [2] straight, 10 mm; [3] straight, 8 mm; [4] tilted, 12-16 mm). The resulting implant-supported polygon was measured for each of the 4 groups using three-dimensional planning software. RESULTS: The mean sagittal depth of the supported polygon in Group 1 was 9.9 mm (standard deviation [SD] 4.4) on the right and 10.2 mm (SD 4.4) on the left, and it was 33.7 mm (SD 5.8) in width. For Group 2, the mean sagittal depth was 11.5 mm (SD 5.0) on the right and 11.9 mm (SD 4.7) on the left, and the width was 35.2 mm (SD 5.6). The measurements for Group 3 were 13.8 mm (SD 4.9) deep on the right, 13.8 mm (SD 5.1) deep on the left, and 37.0 mm (SD 5.4) in width. For Group 4, the depth was 15.8 mm (SD 4.9) on the right and 16.4 mm (SD 5.8) on the left, and the width was 39.0 mm (SD 5.1). CONCLUSION: The area of implant-retained prosthesis support can be enlarged by the use of tilted implants (12 to 16 mm in length, 42 to 45 degrees) compared to the use of straight 8-mm implants (resulting increase: about 15%).

Fracture Strength of Monolithic All-Ceramic Crowns on Titanium Implant Abutments.

PURPOSE: The fracture strengths of all-ceramic crowns cemented on titanium implant abutments may vary depending on crown materials and luting agents. The purpose of this study was to examine differences in fracture strength among crowns cemented on implant abutments using crowns made of seven different monolithic ceramic materials and five different luting agents. MATERIALS AND METHODS: In total, 525 crowns (75 each of Vita Mark II, feldspathic ceramic [FSC]; Ivoclar Empress CAD, leucite-reinforced glass ceramic [LrGC]; Ivoclar e.max CAD, lithium disilicate [LiDS]; Vita Suprinity, presintered zirconia-reinforced lithium silicate ceramic [PSZirLS]; Vita Enamic, polymer-reinforced fine-structure feldspathic ceramic [PolyFSP], Lava Ultimate; resin nanoceramic [ResNC], Celtra Duo; fully crystallized zirconia-reinforced lithium silicate [FcZirLS]) were milled using a CAD/CAM system. The inner surfaces of the crowns were etched and silanized. Titanium implant abutments were fixed on implant analogs, and airborne-particle abrasion was used on their exterior specific adhesion surfaces (Al2O3, 50 µm). Then, the abutments were degreased and silanized. The crowns were cemented on the implant abutments using five luting agents (Multilink Implant, Variolink II, RelyX Unicem, GC FujiCEM, Panavia 2.0). After thermocycling for 5,000 cycles (5 to 55°C, 30 seconds dwell time), the crowns were subjected to fracture strength testing under static load using a universal testing machine. Statistical analyses were performed using analysis of variance (α = .0002) and the Bonferroni correction. RESULTS: No significant difference among the luting agents was found using the different all-ceramic materials. Ceramic materials LiDS, PSZirLS, PolyFSP, and ResNC showed significantly higher fracture strength values compared with FSC, FcZirLS, and LrGC. The PSZirLS especially showed significantly better results. CONCLUSION: Within the limitations of this study, fracture strength was not differentially affected by the various luting agents. However, the fracture strength was significantly higher for PSZirLS, PolyFSP, ResNC, and LiDS ceramics than for the FSP, LrGC, and the FcZirLS ceramic with all luting agents tested.

Dental color matching: A comparison between visual and instrumental methods.

The aim of this study was to compare the agreement rate (%) and color difference (ΔE*ab) of three dental color-measuring devices, with the visual shade identification. The tooth color were determined by two operators, which were advised to select a VITA classic shade tab in each other's agreement. The Shadepilot (SP), CrystalEye (CE) and ShadeVision (SV) were used to measure tooth color. Statistically analyses include agreement rate (%), color difference (ΔE*ab), McNemar test (p=0.05), Student's t-test (p=0.05) and Bland Altman scatterplots. The SP had an agreement of 56.3% with the visual shade determination, the CE 49.0% and SV 51.3%. ΔE*ab of the visually and instrumentally selected shade tabs and natural teeth were frequently above the threshold for acceptability. Comparing both methods, for SP ΔE*ab values differ in a range of clinical acceptability.

Influence of porcine-derived collagen matrix on endothelial progenitor cells: an in vitro study.

Porcine-derived collagen matrix (PDCM) has been reported as a promising alternative to autogenous soft tissue grafts in periodontal plastic surgery. The aim of this study was to analyze the influence of a novel PDCM on endothelial progenitor cells (EPC) in vitro. EPC were isolated from human peripheral blood, cultured and transferred on the PDCM (mucoderm®). Tissue culture polystyrene surface (TCPS) served as control. Cell viability of EPC on PDCM was measured by a MTT and PrestoBlue® assay. Migration ability was tested using a Boyden migration assay. A ToxiLight® assay was performed to analyze the influence of PDCM on adenylate kinase (ADK) release and apoptosis rate of EPC. Using the MTT assay, EPC cultured on PDCM demonstrated a significantly increased cell viability compared to the control group at days 3, 6 and 12 (p each <0.001). According to the PrestoBlue® assay, EPC showed a significant increase of cell viability compared to the control group at 48, 72, and 96 h (p each <0.001). In the Boyden migration assay, a significantly increased EPC migration ability could be observed after 3-12 days (p each ≤0.001). No significantly increased apoptosis rate of EPC on PDCM could be observed with exception after 96 h (p each >0.05). Overall, our results suggest a good biocompatibility of PDCM without any cytotoxic effects on EPC, which might support a rapid revascularization and therefore a sufficient ingrowth of the PDCM.