Conventionally and digitally fabricated removable complete dentures: manufacturing accuracy, fracture resistance and repairability.

OBJECTIVES: Conventionally and digitally manufactured removable complete dentures with different dentition forms were examined for manufacturing accuracy (trueness, precision), fracture forces under torsional loading and subsequent repairability. METHODS: A total of 90 mandibular prostheses were manufactured. Ten were made using the injection molding technique and finished with prefabricated teeth. 40 bases each, were manufactured subtractively and additively. Digitally the prosthesis' dental arch was divided either into two quadrants or three sextants, or kept as full arch. Afterwards, ten additive and subtractive bases were finished with prefabricated teeth and ten of each with milled quadrants, sextants and full arches. After manufacturing, all specimens were rescanned for accuracy comparisons using the Root Mean Square (RMS). Lastly, all specimens were tested to failure under torsional loading. RESULTS: Conventionally manufactured dentures showed the greatest deviation in accuracy. The type of base manufacturing did not determine the fracture resistance of the prostheses. The dentition form had a significant influence. While prefabricated teeth (86.01 ± 19.76 N) and quadrants (77.89 ± 9.58 N) showed a low fracture resistance, sextants (139.12 ± 21.41 N) and full arches (141.05 ± 17.14 N) achieved the highest fracture forces. Subtractive bases with prefabricated teeth or quadrants were assessed to be repairable, digital dentures with full arch were assessed as not repairable. SIGNIFICANCE: The presented testing set-up is suitable to determine the fracture behavior of dentures rather than of standards. With the possibility of digital design and individual manufacturing, dentures' mechanical stability can be significantly increased, especially with suitable dentition forms.

Strengthening Emotional Development and Emotion Regulation in Childhood-As a Key Task in Early Childhood Education.

The following article deals with emotional development and the development of emotion regulation skills in children during early childhood education, focusing primarily on the importance of the early childhood teacher. Emotion regulation is important for success and wellbeing in further life. It is developed in interaction with parents as attachment figures. Teachers can also be important persons for the child in the context of bonding. This leads to the question of how early childhood teachers can support children learning to regulate their emotions. We analyze with the content analysis, four programs for promoting social and emotional skills that are currently used in Germany. The main question is if the programs include elements that increase teachers' skills in supporting the children in regulating their emotions. The categories to analyze the programs are derived from theories of teacher-child interaction. In addition to programs for promoting emotional and social development, we will discuss aspects of shaping interaction as essential elements in promoting emotion regulation. The conclusion outlines some key implications for educational practice and the importance of developing professional behavior for qualitative teacher-child interactions.

Rapid additive manufacturing of an obturator prosthesis with the use of an intraoral scanner: A dental technique.

A protocol for a completely digital manufacturing process for an obturator prosthesis is described. An intraoral scanner was used to capture the mandible and maxilla together with the sinus defect. The obturator base and the artificial teeth were created with a computer-aided design software program and manufactured by 3-dimensional printing. Stainless steel clasps provided the retention for the prosthesis.

Additive Manufacturing: A Comparative Analysis of Dimensional Accuracy and Skin Texture Reproduction of Auricular Prostheses Replicas.

PURPOSE: The use of computer-aided design/computer-aided manufacturing (CAD/CAM) and additive manufacturing in maxillofacial prosthetics has been widely acknowledged. Rapid prototyping can be considered for manufacturing of auricular prostheses. Therefore, so-called prostheses replicas can be fabricated by digital means. The objective of this study was to identify a superior additive manufacturing method to fabricate auricular prosthesis replicas (APRs) within a digital workflow. MATERIALS AND METHODS: Auricles of 23 healthy subjects (mean age of 37.8 years) were measured in vivo with respect to an anthropometrical protocol. Landmarks were volumized with fiducial balls for 3D scanning using a handheld structured light scanner. The 3D CAD dataset was postprocessed, and the same anthropometrical measurements were made in the CAD software with the digital lineal. Each CAD dataset was materialized using fused deposition modeling (FDM), selective laser sintering (SLS), and stereolithography (SL), constituting 53 APR samples. All distances between the landmarks were measured on the APRs. After the determination of the measurement error within the five data groups (in vivo, CAD, FDM, SLS, and SL), the mean values were compared using matched pairs method. To this, the in vivo and CAD dataset were set as references. Finally, the surface structure of the APRs was qualitatively evaluated with stereomicroscopy and profilometry to ascertain the level of skin detail reproduction. RESULTS: The anthropometrical approach showed drawbacks in measuring the protrusion of the ear's helix. The measurement error within all groups of measurements was calculated between 0.20 and 0.28 mm, implying a high reproducibility. The lowest mean differences of 53 produced APRs were found in FDM (0.43%) followed by SLS (0.54%) and SL (0.59%)--compared to in vivo, and again in FDM (0.20%) followed by SL (0.36%) and SLS (0.39%)--compared to CAD. None of these values exceed the threshold of clinical relevance (1.5%); however, the qualitative evaluation revealed slight shortcomings in skin reproduction for all methods: reproduction of skin details exceeding 0.192 mm in depth was feasible. CONCLUSION: FDM showed the superior dimensional accuracy and best skin surface reproduction. Moreover, digital acquisition and CAD postprocessing seem to play a more important role in the outcome than the additive manufacturing method used.

Comparison of prospective head motion correction with NMR field probes and an optical tracking system.

PURPOSE: The aim of this study was to compare prospective head motion correction and motion tracking abilities of two tracking systems: Active NMR field probes and a Moiré phase tracking camera system using an optical marker. METHODS: Both tracking systems were used simultaneously on human subjects. The prospective head motion correction was compared in an MP2RAGE and a gradient echo sequence. In addition, the motion tracking trajectories for three subjects were compared against each other and their correlation and deviations were analyzed. RESULTS: With both tracking systems motion artifacts were visibly reduced. The precision of the field probe system was on the order of 50 µm for translations and 0.03° for rotations while the camera's was approximately 5 µm and 0.007°. The comparison of the measured trajectories showed close correlation and an average absolute deviation below 500 µm and 0.5°. CONCLUSION: This study presents the first in vivo comparison between NMR field probes and Moiré phase tracking. For the gradient echo images, the field probes had a similar motion correction performance as the optical tracking system. For the MP2RAGE measurement, however, the camera yielded better results. Still, both tracking systems substantially decreased image artifacts in the presence of subject motion. Thus, the motion tracking modality should be chosen according to the specific requirements of the experiment while considering the desired image resolution, refresh rate, and head coil constraints.

Effect of surface modification of zirconia on cell adhesion, metabolic activity and proliferation of human osteoblasts.

Titanium dental implants with sandblasted and/or acid-etched surfaces have shown clinical superiority in comparison to their smooth, machined counterparts, and are now state of the art. Sandblasting of finished, sintered zirconia implants, however, will damage the surface structure and affect the mechanical properties. To improve osseointegration of zirconia dental implants without impairing the original mechanical strength by crack initiation and partial phase transformation from tetragonal to monoclinic, roughening of the zirconia surface by sandblasting before the final sintering step was employed. Impact of the treatments on cellular reactions of SAOS-2 human osteoblast-like cells was investigated. Sandblasting of Yttrium-stabilized zirconia (Y-TZP) with 120 µm and 250 µm Al2O3 enhanced average roughness (Sa) from 0.28 µm to 4.1 µm and 5.72 µm, respectively. Cell adhesion of SAOS-2 osteoblasts was enhanced up to 175% on sandblasted surfaces, compared to the machined zirconia reference (100%). Metabolic activity and proliferation in the logarithmic growth phase (24-48 h) were not significantly affected. Sample surface coverage by the cells after prolonged incubation (72 h) was markedly decreased on the roughened samples, indicating a shift towards increased differentiation on these surfaces. The approach investigated here to roughen zirconia implants by sandblasting before sintering shows potential to improve the clinical performance of ceramic dental implants.

Mandibular reconstruction with a prefabricated free vascularized fibula and implant-supported prosthesis based on fully three-dimensional virtual planning.

Because optimal reconstruction of maxillofacial defects requires functional rehabilitation, the current study demonstrates the successful secondary reconstruction of a large mandibular continuity defect using a fully digitally planned prefabricated free vascularized fibula with immediate implant-supported prosthodontic restoration. A 56-year-old man presented with a large mandibular continuity defect after resection of an enlarged squamous cell carcinoma arising from the floor of the mouth. For secondary reconstruction, the shape of the neomandible and implant position for support of the lower prosthesis were planned virtually. The combined cutting and drilling guide was printed in 3 dimensions. In a 2-step surgical approach, first, the implants were inserted into the fibula and covered with a split-thickness skin graft to form a neogingiva. In a second operation, the fibula was harvested, osteotomized, and fixed with the denture on the preinserted implants. The fibula was placed to its final position guided by the occlusion. Using three-dimensional virtual backward planning, it was feasible to perform a mandibular reconstruction with immediate prosthetic rehabilitation.

[Salter-harris fractures in dogs and cats considering problems in radiological reports--a retrospective analysis of 245 cases between 1997 and 2012]. / Salter-Harris-Frakturen bei Hund und Katze unter Berücksichtigung radiologischer Befundungsprobleme--eine retrospektive Auswertung von 245 Patienten aus den Jahren 1991-2012.

To identify typical trauma patterns or frequent radiological pitfalls that could help a radiologists in their daily routine, a retrospective study of Salter-Harris fractures in dogs and cats was performed. Radiographs obtained in the period 1991-2012 of 288 fractures in 245 patients with suspected injuries affecting growth plates in the appendicular skeleton were retrieved from the imaging archive. The femur was the bone most frequently affected (46.5%), followed by the humerus (19.8%), tibia (13.5%) and radius (11.8%). The distal growth plate was in all bones more often involved than the proximal growth plate (79.5% vs. 20.5%). The frequency of Salter-Harris fractures was 39.9% type I, 37.8% type II, 3.1% type III and 19.1% type IV. In dogs the most common physeal fracture was a type IV fracture of the of the distal femur. Radiographically, physeal fractures were recognized by at least two Roentgen signs, including change in opacity, displacement of the epiphysis or the Thurston-Holland sign. On the basis of the review, the original radiographic reports of 44/288 fractures were considered erroneous regarding the incorrect Salter Harris grouping. In 5/44 instances, the radiological examination had technical deficiencies that may have contributed to the errors, including 3 with oblique projections. Minimal variations in the projection was evident in the majority of reviewed cases. Measures to help optimize radiographic reports will be discussed.

Spontaneous re-eruption of a permanent maxillary central incisor after 15 years of ankylosis--a case report.

Intrusion injuries are considered among the most severe forms of dental trauma, potentially leading to ankylosis as a late consequence. In 1991, a 7-year-old boy suffered a traumatic intrusion leading to an infraposition of tooth 21 along with its immobility. Based on the clinical findings, including bright-sounding percussion testing, disappearance of the periodontal space and a failed attempt at orthodontic movement, a diagnosis of ankylosis was made. Following prosthetic restoration of the infrapositioned tooth, spontaneous re-eruption occurred 15 years later. With the help of a partial multibracket appliance, the tooth could be adjusted to occlusal level and was then restored to the patient's satisfaction. Radiographically, it was demonstrated that extrusion of the tooth had been accompanied by a significant gain in local alveolar bone volume. While a wait-and-see strategy cannot be recommended as a treatment option following ankylosis, considering that spontaneous re-eruption after several years is an extremely rare finding, elucidating the mechanisms at work in spontaneous re-eruption at a cellular level might create an opportunity for iatrogenic triggering of re-eruption, thus paving the way to new forms of therapy.

Application times for the single-step/double-mix technique for impression materials in clinical practice.

Hydrophilicity of unset impression materials underlies changes occurring during working time. Hence, the clinical application time when impression materials contact oral tissues after mixing may play a critical role in successful impressions. The aim of this study was to analyze the clinical time course of impression taking applying the single-step/double-mix technique. Application times of 86 impressions, comprising 265 prepared teeth and 46 implants, taken by 14 different clinicians at a university dental clinic were analyzed. The mean time from loading the impression tray until its final position in the patient's mouth (total application time) was 51.2 seconds; confidence intervals were 46.9 (lower limit) and 55.5 (upper limit). The number of registered teeth and implants did not influence the duration of impression taking. Related to wettability data, several polyvinyl siloxane impression materials show decreased hydrophilicity with respect to estimated application times. The authors suggest considering clinically relevant application times for impression taking in future in vitro studies on physicochemical characteristics of impression materials.

Tattoo inks contain polycyclic aromatic hydrocarbons that additionally generate deleterious singlet oxygen.

In the past years, tattoos have become very popular worldwide, and millions of people have tattoos with mainly black colours. Black tattoo inks are usually based on soot, are not regulated and may contain hazardous polycyclic aromatic hydrocarbons (PAHs). Part of PAHs possibly stay lifelong in skin, absorb UV radiation and generate singlet oxygen, which may affect skin integrity. Therefore, we analysed 19 commercially available tattoo inks using HPLC and mass spectrometry. The total concentrations of PAHs in the different inks ranged from 0.14 to 201 microg/g tattoo ink. Benz(a)pyrene was found in four ink samples at a mean concentration of 0.3 +/- 0.2 microg/g. We also found high concentrations of phenol ranging from 0.2 to 385 microg/g tattoo ink. PAHs partly show high quantum yields of singlet oxygen (Phi(Delta)) in the range from 0.18 to 0.85. We incubated keratinocytes with extracts of different inks. Subsequent UVA irradiation decreased the mitochondrial activity of cells when the extracts contained PAHs, which sufficiently absorb UVA and show simultaneously high Phi(Delta) value. Tattooing with black inks entails an injection of substantial amounts of phenol and PAHs into skin. Most of these PAHs are carcinogenic and may additionally generate deleterious singlet oxygen inside the dermis when skin is exposed to UVA (e.g. solar radiation).

Tattooing of skin results in transportation and light-induced decomposition of tattoo pigments--a first quantification in vivo using a mouse model.

Millions of people are tattooed with inks that contain azo pigments. The pigments contained in tattoo inks are manufactured for other uses with no established history of safe use in humans and are injected into the skin at high densities (2.5 mg/cm(2)). Tattoo pigments disseminate after tattooing throughout the human body and although some may photodecompose at the injection site by solar or laser light exposure, the extent of transport or photodecomposition under in vivo conditions remains currently unknown. We investigated the transport and photodecomposition of the widely used tattoo Pigment Red 22 (PR 22) following tattooing into SKH-1 mice. The pigment was extracted quantitatively at different times after tattooing. One day after tattooing, the pigment concentration was 186 microg/cm(2) skin. After 42 days, the amount of PR 22 in the skin has decreased by about 32% of the initial value. Exposure of the tattooed skin, 42 days after tattooing, to laser light reduced the amount of PR 22 by about 51% as compared to skin not exposed to laser light. A part of this reduction is as a result of photodecomposition of PR 22 as shown by the detection of corresponding hazardous aromatic amines. Irradiation with solar radiation simulator for 32 days caused a pigment reduction of about 60% and we again assume pigment decomposition in the skin. This study is the first quantitative estimate of the amount of tattoo pigments transported from the skin into the body or decomposed by solar or laser radiation.

[Promotion of resilience in institutions of early childhood education (kindergarten)--first results of a prevention project]. / Kinder Stärken! Resilienzförderung in der Kindertageseinrichtung.

This article focuses on first results of a prevention project dealing with the promotion of resilience in institutions of early childhood education (e.g. kindergarten). In four institutions with 278 children the early childhood educators are trained and the children themselves take part in a special training programme. Additionally the parents are given the chance to participate in special courses and individual counselling, while the institutions are involved in networks with other institutions, e.g. for educational guidance. The process and the effects of the programme are evaluated in a control group design by qualitative and quantitative (standardised tests) methods. After a first project stage of six months interim findings show a positive response in all target groups. There are significant positive results on the children of the treatment group in their self-concept and in their cognitive development.

Light-induced decomposition of indocyanine green.

PURPOSE: To investigate the light-induced decomposition of indocyanine green (ICG) and to test the cytotoxicity of light-induced ICG decomposition products. METHODS: ICG in solution was irradiated with laser light, solar light, or surgical endolight. The light-induced decomposition of ICG was analyzed by high-performance liquid chromatography (HPLC) and mass spectrometry. Porcine retinal pigment epithelial (RPE) cells were incubated with the light-induced decomposition products of ICG, and cell viability was measured by trypan blue exclusion assay. RESULTS: Independent of the light source used, singlet oxygen (photodynamic type 2 reaction) is generated by ICG leading to dioxetanes by [2+2]-cycloaddition of singlet oxygen. These dioxetanes thermally decompose into several carbonyl compounds. The decomposition products were identified by mass spectrometry. The decomposition of ICG was inhibited by adding sodium azide, a quencher of singlet oxygen. Incubation with ICG decomposition products significantly reduced the viability of RPE cells in contrast to control cells. CONCLUSIONS: ICG is decomposed by light within a self-sensitized photo oxidation. The decomposition products reduce the viability of RPE cells in vitro. The toxic effects of decomposed ICG should be further investigated under in vivo conditions.

Modern tattoos cause high concentrations of hazardous pigments in skin.

BACKGROUND: Modern tattoo colourants frequently consist of azo pigments that not only contain multiple impurities but also are originally produced for car paint and the dyeing of consumer goods. OBJECTIVE: In order to be able to assess the health risk of tattoos, it is important to determine the pigment concentration in human skin. METHODS: We tattooed excised pigskin and human skin with a common tattoo pigment (Pigment Red 22) under various conditions. After tattooing, we quantitatively extracted the pigment in order to determine the pigment concentration in skin. RESULTS: The concentration of pigments ranged from about 0.60 to 9.42 mg/cm(2) of tattooed skin (mean value 2.53 mg/cm(2)) depending upon the size of the pigment crystals, the pigment concentration applied to the skin surface, and the respective procedure of tattooing. CONCLUSION: In conclusion, high concentrations of colourants are injected into the skin during tattooing and based upon this quantification, a risk assessment of tattooing ought to be carried out.

Azo pigments and a basal cell carcinoma at the thumb.

Basal cell carcinoma is the most common malignant neoplasm of the skin, whereas the localization at the nail unit is very rare. We report the case of a 58-year-old patient with a periungual basal cell carcinoma at the thumb. The specific feature of the reported case is the frequent exposure to fishing baits that the patient had stained with an unknown colorant. The use of chromatography, mass spectrometry and infrared spectroscopy revealed the colorant as the azo pigment Solvent Red 8. Solvent Red 8 is a widespread synthetic azo pigment that is applied to stain consumer products. Compounds such as Solvent Red 8 can be cleaved to carcinogenic amines under, for example, light exposure, in particular after incorporation into the human body. As a result of the frequent skin contact to this azo pigment, this hazard compound might have induced the basal cell carcinoma in our patient.

Photochemical cleavage of a tattoo pigment by UVB radiation or natural sunlight.

BACKGROUND: Millions of people have at least one tattoo. Complex and light absorbing molecules are implanted in the skin. When tattooed skin receives UV radiation or natural sunlight, photochemical cleavage of the pigments may occur. As a first step, we dissolved pigments in a suitable solvent and analyzed them after light irradiation. METHODS: The widespread Pigment Red 22 was dissolved in different solvents. The solutions were irradiated with either UVB radiation (up to 8 h) or with natural sunlight (110 days). After irradiation, the solutions were analyzed by means of liquid chromatography and mass spectrometry. RESULTS: A clear cleavage of the pigment was detected in all solvents and the primary decomposition products were identified. In tetrahydrofuran and dioxane, the pigment concentration decreased significantly during UVB irradiation, whereas the pigment was completely destroyed during sunlight exposure. In chloroform and dichloromethane, the pigment concentration decreased slightly during UVB irradiation, whereas the pigment was almost completely destroyed during sunlight exposure. CONCLUSION: Since chloroform and dichloromethane do not affect the cleavage process, these solvents are optimal for such in vitro experiments. We have shown the cleavage of the tattoo pigment Red 22 when exposed to UVB radiation or natural sunlight. The decomposition products are hazardous showing a potential risk of being toxic or even carcinogenic. At present, a risk assessment is not feasible since the concentration of pigments and their decomposition products in skin are unknown.

Establishment of an extraction method for the recovery of tattoo pigments from human skin using HPLC diode array detector technology.

Tattooing is a widespread process of puncturing pigments into skin, whereas the resulting concentration inside the skin remains unknown. Many tattoo colorants are organic pigments, such as azo pigments, manufactured for other uses. To remove tattoos from skin, laser pulses at very high intensities are applied to the skin to destroy the tattoo pigments. Recent investigations have shown that several azo compounds are cleaved by laser light leading to potentially toxic or carcinogenic compounds. To assess the risk of tattooing and laser treatment of tattoos, the concentration of the pigments and their decomposition products in the skin must be determined. Therefore, an extraction method was established to determine the concentration of tattoo pigments and decomposition products quantitatively. The extraction of two widely used azo compounds, Pigment Red 22 and Pigment Red 9, and their laser-induced decomposition products, 2-methyl-5-nitroaniline, 4-nitrotoluene, 2,5-dichloraniline, and 1,4-dichlorobenzene, was accomplished using recovery experiments and HPLC-DAD technology. Despite the poor solubility of the pigments, a nearly complete recovery from aqueous suspension (> 92%) or lysed skin (> 94%) was achieved. The decomposition products were extracted from aqueous suspension or skin showing a recovery of up to 100%, except for the very volatile 1,4-DCB.

Singlet oxygen generation by UVA light exposure of endogenous photosensitizers.

UVA light (320-400 nm) has been shown to produce deleterious biological effects in tissue due to the generation of singlet oxygen by substances like flavins or urocanic acid. Riboflavin, flavin mononucleotide (FMN), flavin adenine dinucleotide (FAD), beta-nicotinamide adenine dinucleotide (NAD), and beta-nicotinamide adenine dinucleotide phosphate (NADP), urocanic acid, or cholesterol in solution were excited at 355 nm. Singlet oxygen was directly detected by time-resolved measurement of its luminescence at 1270 nm. NAD, NADP, and cholesterol showed no luminescence signal possibly due to the very low absorption coefficient at 355 nm. Singlet oxygen luminescence of urocanic acid was clearly detected but the signal was too weak to quantify a quantum yield. The quantum yield of singlet oxygen was precisely determined for riboflavin (PhiDelta = 0.54 +/- 0.07), FMN (PhiDelta = 0.51 +/- 0.07), and FAD (PhiDelta = 0.07 +/- 0.02). In aerated solution, riboflavin and FMN generate more singlet oxygen than exogenous photosensitizers such as Photofrin, which are applied in photodynamic therapy to kill cancer cells. With decreasing oxygen concentration, the quantum yield of singlet oxygen generation decreased, which must be considered when assessing the role of singlet oxygen at low oxygen concentrations (inside tissue).